tag:russell-davison.blog.co.uk,2009-11-10:/MokoFeed2009-11-10T05:30:37+01:00tag:russell-davison.blog.co.uk,2007-01-24:/2007/01/24/plastics_technology~1613352/russell-davison2007-01-24T14:58:05+01:002007-01-24T14:58:05+01:00<strong>INJECTION MOULDING<br> <br> </strong>Injection moulded parts can be produced with; ribs, varying thickness and good surface finishes using all thermoplastic materials.  The orientation of molecules and reinforcement occurs during the process.  High pressure, nonuniform polymer shrinkage and orientation can lead to warpage and shrinkage over ribs and bosses.  Warpage is most apparent with crystalline materials and with large, flat parts.  Methods of controlling these effects are described below.<br> <br> Plastic granules are softened during injection moulding and forced under pressure into a cold mould through small orifices or gates.  Pressure is maintained on the material after injection is complete so as to reduce shrinkage of the ribs and bosses as the material cools.  Pressure is higher at the gates because it will not transfer effectively through the compressible and rapidly cooling melt.  The additional packing pressure leads to a higher density of material near the gates and causes internal stresses.  These stresses tend to be partially relieved when the part is removed from the tool, resulting in warpage.<br> <br> The plastic melt must flow from the gates, through the narrow gap between cooled mould surfaces, to the edge of the tool.  The gap becomes narrower as the material flows because some of the melt solidifies at the mould surface.  The pressure, flow rate and distance between the mould faces must be great enough, and the material viscosity low enough, to fill the mould before the solidifying material closes off the flow path. For each material and part thickness, there is a maximum practical flow length from a gate.<br> <br> High pressures and narrow flow paths increase the orientation, which becomes greater as the gap freezes off.  Therefore, the orientation at the centre of the part wall is much higher than at the surface.  For the same reason, orientation is highest near the gates.  The gates should not be areas that are likely to suffer impact or other stresses, such as chemical attack.<br> <br> The maximum practical thickness of the part is about four millimetres.  Above this thickness, cooling time becomes excessive.  The minimum normal thickness for injection moulding is about one millimetre.  Below this level, the party cools before the tool is filled and orientation is excessive.<br> <br> The largest readily available injection moulding machines have a 3000 tonf clamping force, which restricts part size to about one cubic metre or less, for more difficult and filled materials. The flow length of the plastics from any one gate is limited to about 500mm with a 3mm wall thickness.    Therefore, multiple gates must be used for large parts. Gate design and position are very important for reducing part warpage and add to the complexity of the orientation effects.<br> <br> The surface finish of injected moulded parts replicates the mould surface as it cools in contact with the surface, except over ribs and bosses.  Part design must be aimed at keeping ribs and bosses away form the back side of visible surfaces, reducing material in the rib root.  With filled or reinforced materials, the surface tends to be dull shows flow marks.<br> <br> Cycle times vary from less than a minute to five minutes.  Injection moulding is the most useful thermoplastic processing method.  However, there are size limitations and a tendency towards warpage in flat parts.  Shrin<p> <small> <a href="http://russell-davison.blog.co.uk/2007/01/24/plastics_technology~1613352/#comments">Comments</a> </small> </p>tag:russell-davison.blog.co.uk,2006-10-31:/2006/10/31/venture_opportunity_screening~1281010/russell-davison2006-10-31T13:23:40+01:002006-10-31T13:23:40+01:00I originally wrote this article, “Venture opportunity screening” in November 2003.<br><br>An opportunity has been screened for the export of handcrafted goods from Singapore and the venture appears attractive. New technology and new business processes are used by the venture to provide small retailers of antiques clocks, gifts, handicrafts and home décor with handcrafted goods from Asia by 15 Kg air parcels, delivered in 7 days. The average value of each consignment is S$800 and credit card payment, with order, gives UK retailers 4 weeks to 7 weeks credit with the card company, whilst the venture is assured payment by VISA and Mastercard monthly. Direct mail and telemarketing are used to create and penetrate the market and bilingual staff are close to Asian suppliers and possess superior customer service skills.<br><br>A quick screening of the new venture identifies the potential market of small UK retailers and the gross margin is estimated to be 50%. The competitive advantages identified are identified as low fixed costs, control over costs, location and people advantages. The value created is 10% profit after tax and an IPO exit mechanism is foreseen after 3 years.<br><br>The opportunity concept takes advantage of the recent halving of prices for Transpacific freight and international call costs in the last couple of years and new techniques for receiving assured payment from international customers. The new venture strategy is to penetrate 10% of the market of UK retailers who sell antiques, clocks, gifts, handicrafts and home décor.<br><br>The market profile is of reachable customers who seek product variety. The competition is fragmented and market sizes are estimated as S$20M, S$80M and S$100M in the UK, US and Europe, respectively. The venture economics profile is of low capital requirements and favourable free cash flow characteristics. The time to break even is 15 months. The IPO exit mechanism is estimated to harvest S$2M for the founder in three years. The venture provides a good fit with the goals of the founder and a bilingual team will be created within the first 2 years of operation. Strategic differentiation from the competition is by superior customer service, use of technology, pricing and product quality. The market entry strategy is to create customer awareness that it is now possible to quickly receive quality Asian goods in small quantities at a competitive price from the newly formed company.<br><br>The reasons for making the company believe that the idea is an opportunity are concerned with the main components of customer need, premium pricing, underlying value creation proposition, market niche and product mix. Small UK retailers need a variety of high value products to differentiate themselves from the larger UK retailers and to compensate for their lower lever of sales activity. They are required to purchase goods in modest volumes from wholesalers and UK manufacturers to realize wholesale discounts and are prepared to pay a premium to reduce their investment in inventory. The new venture has an underlying value creation proposition of supplying UK retailers direct in more frequent, smaller volumes to reduce inventory and to take advantage of lower freight costs and international telemarketing call costs. The marker niche of UK retailers selling antiques, clocks, gifts, handicrafts and home décor is chosen to avoid dealing with the end-user consumer, whose average order value would be unlikely to exceed S$100, unacceptably increasing the administration costs. The product mix is carefully chosen to include only those items whose sales price to weight ratio is high, to ensure low air parcel distribution costs (as a percentage of the selling price%<p> <small> <a href="http://russell-davison.blog.co.uk/2006/10/31/venture_opportunity_screening~1281010/#comments">Comments</a> </small> </p>tag:russell-davison.blog.co.uk,2006-10-27:/2006/10/27/small_enterprises~1267544/russell-davison2006-10-27T14:41:18+02:002006-10-27T14:41:18+02:00I originally wrote this article, “Small enterprises” in October 2003<br><br><span>CASE STUDY : BURT’S BEES</span><br><br>An opportunity is defined as consisting of an idea and other components. The following enterprise case study allows comparison with other companies in the industry and shows little investment, small market share, low wages and low productivity for Burt’s Bees. It is explained that the company's success is due to it's uniqueness, Roxanne's qualities, her family, marketing and resource management. The company should keep to it's plan of producing in North Carolina to allow the value of the company to continue to grow, prior to harvesting. According to Timmons and Spinelli (2003:106):<br><br>“Roxanne Quimby sat in the president's office of Burt's Bees newly relocated manufacturing facility in Raleigh, North Carolina. She was surrounded by unpacked boxes and silence from the unmoving machines with no one there to operate them. Quimby looked around and asked herself, "Why did I do this?" She felt lonely and missed Maine, Burt's Bees' previous home. Quimby had founded and built Burt's Bees, a manufacturer of beeswax-based personal care products and handmade crafts, in central Maine and wasn’t convinced she shouldn't move it back there. She explained:<br><br>“When we got to North Carolina, we were totally alone. I realized how much of the business existed in the minds of the Maine employees. There, everyone had their mark on the process. That was all lost when we left Maine in 1994. I just kept thinking 'Why did I move Burt's Bees?' I thought I would pick the company up and move it and everything would be the same. Nothing was the same except that I was still working 20-hour days.”<br><br>Quimby had profound doubts about this move to North Carolina and was seriously considering moving back to Maine. She needed to make a decision quickly because Burt's Bees was in the process of hiring new employees and purchasing a great deal of manufacturing equipment. If she pulled out now, losses could be minimized and she could hire back each of the 44 employees she had left back in Maine, since none of them had found new jobs yet. On the other hand, it would be hard to ignore all the reasons she had decided to leave Maine in the first place. If she moved Burt's Bees back, she would face the same problems that inspired this move. In Maine, Burt's Bees would probably never grow over $3 million in sales, and Quimby felt it had potential for much more.”<br><br><span>The difference between an idea and an opportunity</span><br><br>An opportunity consists of a market, timing, resources, networks and an idea. An idea is a component, or part, of an opportunity. An idea is of academic interest only when, judged in isolation and is inert, until combined with the other factors to create an opportunity.<br><br>Idea creation is the entrepreneur’s first step to realizing a favourable opportunity. An idea needn't be owned by the entrepreneur and could be regarded as a tool. It could be licensed from another company or establishment. An idea must interact with other components to create an opportunity, but many ideas need to assessed till the right one is chosen to become part of an opportunity. It might be a great innovation or may simply be a more effective way of doing something. Insight or exploration may generate an idea or it may be accidentally stumbled upon.<br><br>Opportunity construction is the next step in the entrepreneurial process where the idea is positioned in the real <p> <small> <a href="http://russell-davison.blog.co.uk/2006/10/27/small_enterprises~1267544/#comments">Comments</a> </small> </p>tag:russell-davison.blog.co.uk,2006-10-24:/2006/10/24/swot_analysis~1257749/russell-davison2006-10-24T20:47:54+02:002006-10-24T20:47:54+02:00 <p>I originally wrote this article, “SWOT analysis” in February 2004.</p> <p><span>SUMMARY</span></p> <p>A case study by Nairn and Strickland (2003) of the Élan Boat Company is used to identify the strengths and weaknesses of the company and the opportunities and threats within the external environment of the company. According to Nairn and Strickland,</p> <p>“Ben Favret, professional water-skier, World Champion, V.S. Champion, and Pro-Tour champion, was resting on the dock after a slalom training run one afternoon when a call came through on his cell phone. Jay Blossman, his high school tennis partner and now politician, was on the other end. Out of the blue, Jay announced to Ben that he was buying American Skier, the competition ski boat company owned by financially troubled American Performance Marine. Ben instantly knew that Jay had found himself a great boat and suspected that he was getting a great deal in buying the company, but he also realized that while Jay was an excellent tennis player, Jay lacked the necessary insider knowledge about building, marketing, and selling ski boats. Excited and eager to be involved in this rare opportunity, Ben was on the next flight to New Orleans to meet Jay and look into the situation.</p> <p>As Ben took the tour of the American Performance Marine plant in Kentwood, Louisiana, he learned that the company had recently filed for bankruptcy. Ben concluded that with his firsthand knowledge of the waterskiing industry and the boatbuilding capabilities that lay before him in the Kentwood plant, he and Jay ought to be able to resurrect the ailing company. With all the enthusiasm and high hopes of an entrepreneur entering the industry of a sport he loves, Ben Favret dove headfirst into building ski boats. In keeping with this excitement and attitude, Ben renamed the company Élan Boats. The word Élan means ‘vigorous spirit and enthusiasm‘.”</p> <p>The purpose of this report is to identify the firm's key capabilities and trends within the macro environment to develop a clear strategy for the Élan Boat Company.</p> <p>The Basic Design School Model is the strategic framework for the analysis. External and internal appraisals are carried out. Key success factors within the external environment and the distinctive competencies of Élan are identified.</p> <p>Opportunities exist for Élan if water sports receive greater publicity and because the profitability and customer service of the market leaders is unsatisfactory. . The success of the company is threatened by a declining market (which is highly cyclical), the competition's established dealer networks, a poor powered watercraft safety record and suppliers locked into the industry leaders.</p> <p>Élan's strengths are it's brand names of 'American Skier' and 'Ben Favret'. The company's weaknesses are its projected profitability and liquidity.</p> <p>The seven conclusions and recommendations of this report are:</p> <p>(1) Consider changing the position of the new plant, in 2004, from Covington to a location within the Great Lakes area, where demand is highest.</p> <p>(2) Investigate rationalization of the company's product range with a view to reducing the product line from eight to one, two or three variants.</p> <p>(3) Raise manufacturing efficiency and lower overhead costs to increase gross margins from 30% to 40% and net profit from between 1% and 5% to 10%.</p> <p>(4) Increase the liquidity of the company to allow for depressed sales until an economic upturn in the U.S. economy. </p> <p> <small> <a href="http://russell-davison.blog.co.uk/2006/10/24/swot_analysis~1257749/#comments">Comments</a> </small> </p>tag:russell-davison.blog.co.uk,2006-10-15:/2006/10/15/managerial_control~1223172/russell-davison2006-10-15T11:24:09+02:002006-10-15T11:24:09+02:00I originally wrote this article, &ldquo;Managerial control&rdquo; in July 2003.<br><br>A group of my friends have what you believe to be the opportunity of a lifetime.<br><br>They graduate this year and the father of one of my friends has asked two of them if they would like to buy the air-conditioning business he founded and operated for thirty years. It has been a very lucrative business for him; today he is a millionaire several times over. They are aware his firm is the leader in its field in their area and they see the possibility of expanding because many new homes are being built locally.<br><br>My friend's father will finance the buyout through a loan, to be paid off over the next ten years. Both of my friends have some degree of expertise in the heating and air-conditioning field since they have both worked for my friend&rsquo;s father during university vacation times. My friend&rsquo;s father has also agreed to be a consultant to the two of them for the first year or so if they need his advice.<br><br>The business has almost 60 well-qualified employees, a large inventory, 40 service trucks in excellent condition and a well established list of clients. At the same time the return on investment has been lower than average for the past three years, labour costs are very high, and the company has attracted only a few new clients during the past two years. In addition they have some indication that the firm is not carrying the most up-to-date heating or air conditioning equipment and the four large structures used to house showrooms and service centres are in need of refurbishment.<br><br>My friends are discussing the possibility of buying the firm. In considering the situation I reviewed the control forms and processes that I would use to ensure effective control over the operation.<br><br>I outlined the control issues and potential problems that I considered relevant to this case. I recommended control processes to be put into place to ensure the continued success of the business. Using my knowledge of the concepts and classification of controls, I applied these concepts of control to their particular situation.<br><br>The proposed purchase, by my friends, of the air-conditioning business raises many issues that are discussed. I've identified ten potential problems with the acquisition. Half of the potential problems are controllable and I propose four control process models to reduce the risk of business failure. <br><br><span>Issues</span><br><br>Organizational control of the air-conditioning business is required if my friends are to be successful in this venture. Daft (2003, p. 654) defines organizational control as the 'systematic process through which managers regulate organizational activities to make them consistent with expectations established in plans, targets and standards of performance.' The importance of control is evidenced by the fact that it is one of the four basic management functions - planning, organizing, leading, controlling, as explained by Robbins, Bergman, Stagg and Coulter (2003). Controlling is required throughout the depth of the organization (strategic, tactical and operational) and the breadth of the organization (financial, operations, information and people).<br><br>As part of the control process, they need systems to measure and compare actual performance. This will allow them to take corrective action if performance deviations are found. They should only control processes which will contribute to the success of their business. One method of selecting these particular processes is by resourc<p> <small> <a href="http://russell-davison.blog.co.uk/2006/10/15/managerial_control~1223172/#comments">Comments</a> </small> </p>tag:russell-davison.blog.co.uk,2006-10-12:/2006/10/12/virtual_team_working~1212130/russell-davison2006-10-12T08:01:42+02:002006-10-12T08:01:42+02:00I originally wrote this article, “Virtual team working” in June 2003. Robbins et al (2003, p.4) define an organisation as being "a deliberate arrangement of people to accomplish some specific purpose." If the people working together within the organisation are separated by distance and/or time then the organisation type can be described as being 'virtual’. It is uncommon to find a fully virtual organisation. Virtual teams however, operating within an organisation, are commonplace and their growth in numbers raises many management issues. <strong>Organisation</strong> The virtual workplace has the potential to allow team members to be more effective by matching work times to when people are likely to be at their best. Greater efficiency can be realized by removing time wasted commuting to, and from, a traditional workplace. Mintzberg's interpersonal, informational and decisional management roles within the virtual workplace may be very different to that of a traditional organisation. Anderson and Shane (2002) report that some virtual teams use shared leadership. They also suggest that having only one team leader can slow decision making. Knowledge management, as an informational role, is a key component of management in virtual organisations according to Witzel (2002). When evaluating the technical, interpersonal and conceptual skills required for a successful virtual team, Adres (2002) quotes various researchers as stating that interpersonal skills are most important. This is because the lack of physical proximity between team members reduces the number of communication channels available and can lead to an increase in 'noise'. It could be argued that contributions from Peters (1992) could be considered as worthy of being added to the works of recognized general administrative theorists like Henri Fayol and Max Weber in predicting that "information networks will be decisive to relative future competitiveness”. However, no, universally accepted approach is yet available for the management of the virtual workplace. Taylor (2001) describes the challenges faced by labour unions in coping with fragmented labour markets in virtual workplaces and introduces the concept of 'e-picketing' by virtual workers as a new form of protest. Globalisation is seen by Hagen (1999) and many other authors as being a major force in the rise of numbers of virtual workplaces. Workforce diversity is created by the employment of minorities and mobility-impaired people who may otherwise experience difficulties in being accepted by certain traditional organisations. Additional diversity is provided by the fact that people of different countries, nationalities, religion or culture may be part of the same virtual team. There are certain dimensions of the successful virtual organisational culture that have common characteristics. High team orientation, low aggressiveness and high innovation and risk taking are important. Conner (2003) suggests that organisations will no doubt have to foster proactive employee behaviour in terms of selection, socialization and policies that encourage individual initiative. <strong>External and internal environments</strong> The interface between the external environment and a virtual organisation can be quite different from that of a traditional organisation. Many virtual organisations extensively utilize outsourcing, strategic alliances and similar partnerships to realize their goals, according to Fitzpatrick and Burke (2001). Walters and Buchanan (2001) believe that more cooperation among competitors, suppliers and customers makes it harder to determine where one company ends and another begi<p> <small> <a href="http://russell-davison.blog.co.uk/2006/10/12/virtual_team_working~1212130/#comments">Comments</a> </small> </p>tag:russell-davison.blog.co.uk,2006-09-30:/2006/09/30/customer_relationship_management~1175445/russell-davison2006-09-30T18:51:50+02:002006-09-30T18:57:37+02:00 <p>I originally wrote this article, “Customer relationship management” in November 2003. A systematic process is used to prepare a comprehensive proposal to a sponsor for approval to implement a Customer Relationship Management (CRM) System in an organisation. The proposed system introduces a new information system and improves organisational productivity. The sponsor is a financial institution. The information system supports the strategic goals of the organisation where it will be implemented. A systematic approach was followed to identify the opportunity and the choice of proposed system is justified. A feasibility study for the system is proposed, including system investigation and the preparation of functional specifications for the intended system (from a managerial viewpoint) and a system implementation plan is given.</p> <p><strong>SUMMARY</strong></p> <p>An investment is proposed for the implementation of a customer relationship management (CRM) system within the client company over a six month period. It is the optimum solution to the client’s problem of how to achieve their sales revenue growth requirement for the next five years.</p> <p>The proposed system has a good fit with the six strategic goals of their business. In particular, it meets the need to secure lifelong customers who buy the most profitable products using the client’s unique service.</p> <p>The problem of achieving sales revenue growth is solved using a systems approach. First, we established that the problem has the four components of; creating customer awareness, encouraging sales, maintaining repeat custom and deciding upon the marketing mix.</p> <p>Six alternative solutions to the problem are appraised. Mass marketing, CRM, local distributors, local sales representatives, advertising and the internet are considered. These possible solutions are evaluated againstthe definedproblem, cost, time and the degree of fit in supporting the business goals.</p> <p>The optimum solution is a CRM system to focus the marketing and sales efforts in the right direction. It is envisaged that the system will help to attract, retain and get customers to spend more with the company. Using a relational database, the system will be used to co-ordinate the direct mail and telemarketing campaigns.</p> <p>A feasibility study is required during the systems analysis and conceptual design phase to ensure that it meets the requirements for data; warehousing,extraction, management, mining, analysis and query. Implementation of the project will proceed only upon a favourable outcome from the feasibility study.</p> <p>Project implementation is in nine stages. The critical stage is that of training staff in system adoption, data mining, use of technology and in how to get system support.<br> <strong><br> INTRODUCTION</strong></p> <p>The client company is a new business venture formed to utilize an opportunity to satisfy a UK demand for Asian products exported from Singapore by air parcel. The target market is small British retailers who already sell antiques, clocks, gifts, handicrafts and home decor. They compete by having product variety, and very few currently sell handcrafted goods from Asia. Their present offerings are either locally made expensively machined products or poor quality imports from wholesale warehouses. The client company offers good quality, high value, low weight, hand-made Asian products by 7 day delivery air parcel for payment by credit card.</p> <p><strong>STRATEGIC GOALS OF THE ORGANIZATION</strong></p> <p>The client company has six strategic goals, and they are:</p> <p>Annual export sales of S$2M in 5 years and 10% net profit after tax - The client company will acquire 500 lifelong European retail outlet customers. The average order </p> <p> <small> <a href="http://russell-davison.blog.co.uk/2006/09/30/customer_relationship_management~1175445/#comments">Comments</a> </small> </p>tag:russell-davison.blog.co.uk,2006-09-30:/2006/09/30/customer_relationship_management~1175425/russell-davison2006-09-30T18:48:39+02:002006-09-30T18:55:34+02:00 <p>I originally wrote this article, &ldquo;Customer relationship management&rdquo; in November 2003. A systematic process is used to prepare a comprehensive proposal to a sponsor for approval to implement a Customer Relationship Management (CRM) System in an organisation. The proposed system introduces a new information system and improves organisational productivity. The sponsor is a financial institution. The information system supports the strategic goals of the organisation where it will be implemented. A systematic approach was followed to identify the opportunity and the choice of proposed system is justified. A feasibility study for the system is proposed, including system investigation and the preparation of functional specifications for the intended system (from a managerial viewpoint) and a system implementation plan is given.</p> <p> SUMMARY</p> <p> An investment is proposed for the implementation of a customer relationship management (CRM) system within the client company over a six month period. It is the optimum solution to the client&rsquo;s problem of how to achieve their sales revenue growth requirement for the next five years.</p> <p> The proposed system has a good fit with the six strategic goals of their business. In particular, it meets the need to secure lifelong customers who buy the most profitable products using the client&rsquo;s unique service.</p> <p> The problem of achieving sales revenue growth is solved using a systems approach. First, we established that the problem has the four components of; creating customer awareness, encouraging sales, maintaining repeat custom and deciding upon the marketing mix.</p> <p> Six alternative solutions to the problem are appraised. Mass marketing, CRM, local distributors, local sales representatives, advertising and the internet are considered. These possible solutions are evaluated againstthe definedproblem, cost, time and the degree of fit in supporting the business goals.</p> <p> The optimum solution is a CRM system to focus the marketing and sales efforts in the right direction. It is envisaged that the system will help to attract, retain and get customers to spend more with the company. Using a relational database, the system will be used to co-ordinate the direct mail and telemarketing campaigns.</p> <p> A feasibility study is required during the systems analysis and conceptual design phase to ensure that it meets the requirements for data; warehousing,extraction, management, mining, analysis and query. Implementation of the project will proceed only upon a favourable outcome from the feasibility study.</p> <p> Project implementation is in nine stages. The critical stage is that of training staff in system adoption, data mining, use of technology and in how to get system support.</p> <p> INTRODUCTION</p> <p> The client company is a new business venture formed to utilize an opportunity to satisfy a UK demand for Asian products exported from Singapore by air parcel. The target market is small British retailers who already sell antiques, clocks, gifts, handicrafts and home decor. They compete by having product variety, and very few currently sell handcrafted goods from Asia. Their present offerings are either locally made expensively machined products or poor quality imports from wholesale warehouses. The client company offers good quality, high value, low weight, hand-made Asian products by 7 day delivery air parcel for payment by credit card.</p> <p> STRATEGIC GOALS OF THE ORGANIZATION</p> <p> The client company has six strategic goals, and they are: Annual export sales of S$2M in 5 years and 10% net profit after tax - The client company will acquire 500 lifelong European retail outlet customers. The average order </p> <p> <small> <a href="http://russell-davison.blog.co.uk/2006/09/30/customer_relationship_management~1175425/#comments">Comments</a> </small> </p>tag:russell-davison.blog.co.uk,2006-09-29:/2006/09/29/enterprise_resource_planning~1170886/russell-davison2006-09-29T07:55:57+02:002006-09-29T08:07:36+02:00I originally wrote this article, &ldquo;Enterprise Resource Planning&rdquo; in October 2003 when I analysed the Fast Food Industry&rsquo;s business models using the competitive forces and value chain analysis models.  I explained that an Enterprise Resource Planning System would provide a good solution to McDonald&rsquo;s challenges.  The critical success factors driving technological were identified and reasons for the failure of information systems, within the fast food industry, were given.  The managerial, organisational and technology factors that caused these problems were explained.  The role and impact of alternative information systems development projects were evaluated in terms of the future strategic directions to be taken by McDonald&rsquo;s and Burger King.  The undertaking of risk evaluations are recommended with each project.  Finally, I recommended an approach to prevent the negative impact of technology upon the people concerned, including the financial performance of the stock.<br> <strong><br> BUSINESS MODEL ANALYSIS</strong><br> <strong><br> Competitive forces model</strong><br> <br> The competitive forces within the fast food Industry can be analyzed using Michael Porter's competitive forces model, described by O'Brien (2003<img src="/img/smilies/icon_razz.gif" alt=":p" class="middle" border="0">.42). These forces are the bargaining powers of customers and suppliers, competitor rivalry, new entrant threats and the threat of substitutes.<br> <br> Customer bargaining power is high and created by fast food outlets being located in close proximity to each other. Prices are readily displayed, giving the customer a real choice of which outlet to buy from.<br> <br> Supplier bargaining power is low because of the concentration of suppliers and the availability of substitute suppliers.<br> <br> Competitor rivalry is high because it is difficult for fast food companies to distinguish themselves from their competitors, so the challenge has intensified.<br> <br> The threat of new entrants is caused by the relatively low entry barriers into the fast food business. MOS Burger and Wendy's are examples of new entrants.<br> <br> The threat of substitute fast food products is affected by trends, such as increased health consciousness, and cost changes.<br> <br> Using Michael Porter's above model; competitive strategies of cost leadership, differentiation, innovation, growth, alliances and other tactics are used in the fast food industry to counter the actions of the above competitive forces.<br> <br> A cost leadership strategy used by fast food companies requires efficient facilities, cost reduction programs and tight cost control by a structured organization with defined responsibilities.<br> <br> An example of a differentiation strategy is that used by McDonald's to distinguish it's products and services from Burger King, etc. by introducing wholesome foods, re-introducing hostesses to carry trays and exploiting the Ronald McDonald mascot for the brand experience.<br> <br> Innovative strategies employed by fast food companies include; operating units in non-traditional markets, dual branding, food science experimentation and test marketing of new products to adjust to the consumer's changing food tastes. For example, on 8th October 2003, McDonald's appointed a Director of Worldwide Nutrition to help guide McDonald's nutrition and active lifestyle initiatives, McDonald's (2003c).<br> <br> The growth strategies of a fast foo<p> <small> <a href="http://russell-davison.blog.co.uk/2006/09/29/enterprise_resource_planning~1170886/#comments">Comments</a> </small> </p>tag:russell-davison.blog.co.uk,2006-09-28:/2006/09/28/online_retail~1167671/russell-davison2006-09-28T08:40:42+02:002006-09-28T08:40:42+02:00I originally wrote this article, &ldquo;Online retail&ldquo; in April 2003.  The effectiveness of the marketing and operations management of Amazon.com are discussed and changes are suggested to improve the management of these functions.<br> <br> Introduction<br> <br> Amazon.com is an international business with operations in Asia, Europe and the US.  Using the latest internet technology, the company trades in goods online and provides services to other companies. Amazon.com owns several patents based upon internet technology.  'Amazon.com Reports Second Profit Ever' (2003) describes how the company's revenue for 2002 was $1.43 billion, up 28% from 2001's figures and annual sales for 2003 are expected to increase by 15 percent upon sales for 2002. Net income for the company in the last quarter of 2002 was $2.7 million, down 48 per cent from the same period in 2001. A $40.6 million exchange rate loss in the euro contributed to this fall as Amazon's $2.15 million borrowings are in this currency.  However, euro fluctuations in 2001 gained the company $16.3 million.<br> <br> International sites in Japan, Germany, France, UK and Canada provided the company with the largest growth during 2002.  The annual revenue for each international site increased by more than 60% in 2002. This created a 76 per cent annual increase for the international business, outside the US, to $461.4 million.<br> <br> The company was founded in 1995 by Jeff Bezos and Schepp (2002) describes how Jeff attributes continuous improvements in computer and internet technology as being key to the success of his operations. According to Moore's Law, a doubling of speed in computing technology takes place every year. Lower prices, faster delivery and new web-site features have been achieved by Amazon as a result of this.<br> <br> International marketing business strategies<br> <br> Amazon's SEC report &lsquo;Annual Report Persuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 For the fiscal year ended December 31,2002' (2003) includes their mission statement, &ldquo;We seek to offer Earth's Biggest Selection and to be Earth's most customer-centric company, where customers can find and discover anything they might want to buy online. We have designed our Web sites to allow millions of new, used and collectible products to be sold by us and by other businesses and individuals worldwide. A product on our Web sites may be listed for sale simultaneously by several different sellers. For instance, a product may be offered by us, by a participant in our Merchants@ program and by a business or individual selling a new, used or collectible version of the product through Amazon Marketplace, zShops or Auctions. We also offer certain e-commerce services to other businesses through our Merchant.com and Syndicated Stores programs." The expansion of Amazon's product and service range appears to be getting to a stage where either the company should consolidate its position within the market or split up the company. There is a danger that customers and management will find it hard to focus and identify with the aims of a company with such a diverse product I services mix.<br> <br> Cost leadership is the international business strategy adopted by Amazon.  Additionally, the company also adopts a strategy which attempts to differentiate its products and services from that of its competitors. The product range is greater than that of high street book sellers. Promotion of Amazon's products is online rather than in-<p> <small> <a href="http://russell-davison.blog.co.uk/2006/09/28/online_retail~1167671/#comments">Comments</a> </small> </p>tag:russell-davison.blog.co.uk,2006-09-27:/2006/09/27/international_business~1164608/russell-davison2006-09-27T10:13:40+02:002006-09-27T10:13:40+02:00 <p>I originally wrote this article, “International business” in March 2003.</p> <p><strong>Reasons for international business growth</strong></p> <p>'Marriott to double Wi-Fi coverage' by Junnarkar (2003) is a good example of the reasons for international business growth. The article reports upon a strategic alliance between Intel and Marriott to provide high speed internet wireless access in the US, Canada and Europe. It shows how market expansion, competitive forces, technological changes and social changes create international business growth needs for both Intel and Marriott.</p> <p>Junnarker (2003) quotes a Marriott vice president as saying, 'High speed internet access is one of the most common requests at our worldwide reservations department.' The article notes that 'many hotspots offer free access, but security concerns often keep business travellers from tapping into the network.' Marriott, with Intel, will expand into the market of providing secure high speed internet access for business travellers. The article also describes how Intel is working with companies such as Marriott to 'verify wireless compatibility.' This approach is essential. The service is being tested in a smaller market to identify product improvements, prior to further market expansion.</p> <p>Competitive forces influence Marriott's decision to enter this new market because, according to the article, 'customers are selecting hotels based on it's [high speed internet access] availability.' Junnarker (2003) also reports on competition to Intel from T-mobile, Cisco and Connexion. The Intel and Marriott strategic alliance will combat these competitive forces. Additionally, the article reports that 'as hot spots proliferate in cafes, hotels, airport lounges and city neighbourhoods, companies from various industries have been seeking ways to provide Wi-Fi services to business travellers. This could mean a drop in Marriott's revenues derived from business communications unless the company also provides the same service.</p> <p>This particular international business growth has only been made possible because of technological changes. Commercially available equipment that utilise wireless network services have only been on the market in the last few years. Telecommunication advancements have made broadband hubs more readily available in diverse locations. Portable computers and hand held devices are now produced, or easily be adapted, to utilise wireless network technology. Business e-mail security systems, once reliant upon land based telephone line country hubs, are now adapted to provide security with web based systems.</p> <p>Social changes also create the need for wireless networks to be made available to the business traveller. The businessman replaced office to hotel communication by fax with e-mail through hotel room telephone lines. A disadvantage of this technique is that large documents and files can take a long time to download. Additionally, the businessman has to conduct all communications in his personal room so that call charges can be billed. This compromises business discussions between travellers in hotel conference rooms and lounges. This change of attitude is reported by Junnarker (2003), 'High-speed access is increasingly available at work and at home, and business travellers aren't willing to compromise a fast connection when they travel. '</p> <p>The timing for this strategic alliance between Intel and Marriott is explained by the accelerating competitive forces at the moment, together with social and technological changes.<br> <strong><br> Foreign direct investment</strong></p> <p>'Cadence to invest $50m' (2003) is a good example of foreign direct investment. The article repor </p> <p> <small> <a href="http://russell-davison.blog.co.uk/2006/09/27/international_business~1164608/#comments">Comments</a> </small> </p>tag:russell-davison.blog.co.uk,2006-09-26:/2006/09/26/new_product_launch~1163457/russell-davison2006-09-26T21:18:13+02:002006-09-26T21:18:13+02:00I originally wrote this article, &ldquo;New product launch&rdquo; in April 2003 when I was asked to spearhead the development of a new product.<br><br><strong>Summary</strong><br><br>There is a customer need for an effective household lizard destroyer. An innovative electrostatic device has been developed and will be launched on 1st July at five retail outlets in Singapore. The company has low fixed costs, low market exit costs and a positive cash flow forecast after product introduction. As the company is new, it has no reputation and promotion is limited to passing trade at five store locations. Opportunities exist for product diversification for the extermination of other household pests. Threats remain from a depressed market caused by economic downturn and raw material supply from China is a concern. A market-penetration pricing objective is chosen. Cost estimation, competitor's prices and the company's ROI objective dictate a selling price of S$28.99 per unit. An action programme of pre-launch tasks has been produced. The marketing budget clearly forecasts that the product should be deleted after 2 years when it is in the decline period of its life cycle and demand has fallen. Sales, financial and personnel controls procedures will be adopted.<br><br><strong>Product life cycle</strong><br><br>The four stages of the product life cycle for the <em>LizaKilla</em>^TM in Singapore&rsquo;s home country market are estimated to be 3 months introduction, 6 months growth, 2 years maturity and 4 years of decline. Although risky and expensive, we choose to gain a pioneer advantage by being first into the market with our electrostatic lizard terminator. Our quality product uses new technology and our company will benefit from the brand awareness of being first to enter the market. We expect to add new design features to the existing product at the latter end of the growth stage to sustain market growth. Our advertising, promotion and pricing will be modified during the maturity stage and the product will be deleted from our range at the latter end of the decline stage.<br><br><strong>Market evaluation</strong><br><br>The market for the <em>LizaKilla</em>^TM is currently latent. Customers need an efficient method of ridding their premises of house lizards but no highly effective product is currently available. Two surveys of 100 home owners each in Jurong, Holland Village and 20 business owners throughout the island show that 70% would be interested in buying our new product if it was economic to buy, maintenance free and was more successful that current methods. We expect competitors to enter the market as it grows and we will defend our share of the market through introducing product innovations. As competition becomes more fierce during the maturity stage of the market, our modified advertising, promotion and pricing will maintain our position as market leader. As the market becomes saturated and demand declines, we will dispose of the product when profits become unattractive.<br><br><strong>Challenges</strong><br><br>We face many challenges with our launch of <em>LizaKilla</em>^TM but we have taken steps to mitigate our risks associated with bad market information, product performance, costs and competition.<br><br><strong>Ideas</strong><br><br>Our idea for this new product came from the need of customers who were dismayed with the ineffective traditional method of house lizard extermination. We used several creativity techniques to provide a short list of six alternative product designs. The electrostatic device was chosen in preference to our other alternatives of ultrasonic, mechanical, electrical and chemical device ideas.<br><br><strong>Concept to strategy</strong><br><br>Over the last few months, we've developed several <em>LizaKilla</em>^TM prototypes and tested them at various locations throughout Singapore. Prototype MKT01 was the most effective but was not economic to manufacture. Prototype MKT02 suffered from spurious discharges which reduced battery life. The most economic prototype was MKT04, but the structure of this model was no<p> <small> <a href="http://russell-davison.blog.co.uk/2006/09/26/new_product_launch~1163457/#comments">Comments</a> </small> </p>tag:russell-davison.blog.co.uk,2006-09-24:/2006/09/24/marketing_management~1155663/russell-davison2006-09-24T13:21:10+02:002006-09-24T13:21:10+02:00 <p><br> I originally wrote this article, "Marketing management" in March 2003 when Mickey Bakshi, the owner of Hide & Chic Luggage sought my advice.<br> <br> September 2001:<br> <br> Mickey Bakshi was planning the opening of his new store in Parramatta, Sydney, for October 4, 2001. Mickey had worked in the luggage business for over 10 years; he had started with a stall at the Sydney Markets and over the years had established good contacts with suppliers and wholesalers. When he heard about the new Riverbank Shopping Centre being developed in Parramatta he decided the time was right to open his own store.<br> <br> Mickey's vision was for a specialised luggage store offering good quality at value-for-money prices. Apart from Grace Bros and David Jones there was no specialised luggage store in the west of Sydney. The concept of a store specialising in luggage and briefcases had been successful in Sydney city. Mickey checked out other shopping centres in the Sydney metropolitan area, before settling on the Riverbank, Parramatta.<br> <br> He chose the catchy name "Hide & Chic Luggage" for his store. His luggage range included well-known brands: Samsonite, Antler, Paklite and Hedgrain as well as some cheaper unbranded lines. He also offered complementary products: leather briefcases, and small leather goods such as wallets and purses.<br> <br> Parramatta was the third largest CBD in Australia. The Riverside Centre was close to the CBD and would house 50 stores. Around 30% of the stores were already trading, the rest would open over the next 3 to 4 months. Mickey selected his location carefully, finally settling on a site close to Country Road, Bed BathNTable, and David Jones Foodchain, which he believed would ensure passing customers.<br> <br> Riverside was being marketed by the developers as an 'up-market' shopping centre, supported by a $2 million promotional spend spread over the next 12 months. Mickey had placed advertisements in the local paper to create awareness of his new store.<br> <br> October 2001:<br> <br> Reviewing performance week by week following the opening, Mickey was becoming increasingly concerned. His worst fears were being realised; world events through September and the collapse of Ansett Airlines in Australia were having a serious impact on sales. Luggage sales were virtually non-existent, wallets had been his main seller but these alone would not bring in enough turnover or profit.<br> <br> Asmorestores in thecentre opened, customertraffic was beginning to build up; the lunchtime period was especially busy with workers from nearby offices. Mickey believed his prime target market was women aged 25-39 but men were also visiting the store.<br> <br> Mickey decided to extend his product line to include sports bags and other casual bags to counter the falling demand for luggage, and with the Christmas trading season looming. He found he was often having to give a discount to attract customers; he couldn't afford to spend any more on promotion.<br> <br> October 2002:<br> <br> Mickey's business had survived - just. Luggage sales had slowly picked up but were still well below his forecast, and he had continued to stock the sports bags and casual bags to boost sales. He was breaking even, mainly because the landlord had agreed to reduce his rent.<br> <br> Occupancy of the shopping centre had not achieved forecast levels and David Jones had announced the Parramatta Foodchain would close in the next few months. David Jones launched its first Foodchain outlet in Brighton, Melbourne in November 2000, and followed with stores at Hawthorn and St Kilda in Mel </p> <p> <small> <a href="http://russell-davison.blog.co.uk/2006/09/24/marketing_management~1155663/#comments">Comments</a> </small> </p>tag:russell-davison.blog.co.uk,2006-09-21:/2006/09/21/entrepreneur_interview~1146692/russell-davison2006-09-21T11:28:15+02:002006-09-21T11:28:15+02:00I originally wrote this article, “Entrepreneur interview” in July 2003. I interviewed Robin, the owner of a small travel business, in July 2003. It was an enjoyable experience and we discussed the business generally, business turning points, human resources, marketing, IT, owner skills and outside sources. <strong>The business</strong> Insight Vacations (Singapore) Pvt Ltd is a small enterprise located in the Suntec City area of Singapore. It operates within the travel industry. Robin runs the business and he is a wholesaler of holiday tours. Products are supplied to Robin by TIC (The Travel Corporation) and he retails them to travel agents. The company also reaches out to other countries in Asia, through agency agreements, to enable the sale of TIC products beyond Singapore. There are twenty employees of the company and the business was established in 1987. Belat (2000) succinctly describes Robin's products by quoting an employee as saying that "Insight Vacations offers unforgettable good memories like seeing the sunset over San Marco , Venice from your gondola, mixing with locals at a late night cafe in Champs Elysee, soaring above Swiss mountains in a cable car to the summit of Mt. Pilatus". TTC produces several branded products and Robin markets three of them, from Singapore, to travel agents in Asia. They are Busabout, Contiki Holidays and Insight Vacations. Busabout is a flexible "hop-on / hop-off" style coach transport network for independent travellers. Contiki Holidays are for 18 to 35 year olds. They are guided tours throughout the world, using all forms of transportation. Insight Vacations are worldwide coach tours. They incorporate centrally located hotels, sightseeing inclusions and quality transportation. The travel industry has undergone many changes in the last decade and will continue to do so at an ever increasing pace. Mergers and acquisitions of travel companies have created large global operators able to undercut the prices of smaller enterprises. Some of the smaller companies, having been in existence for half a century, have either ceased trading or have been acquired by larger companies. Low market entry costs have seen businesses come and go, particularly in the last five years. The definition and roles of supplier, wholesaler, retailer and customer continue to overlap and are being re-moulded within the travel industry. Suppliers, like airlines, now sell direct to the end-user, cutting out the travel agent. Supplier commissions to travel agents have been reduced or capped. Technology has accelerated this change through the use of the internet. Customers are even now able to offer a price that they are willing to pay for a travel service, via the internet, and providers can bid for custom at auctions. In addition to the internal changes taking place within the travel industry, external factors have impacted heavily in the last five years. Many of these external forces have been without precedence and have caused havoc within the tourism industry. Global recession, regional financial crisis, war, terrorism and disease have all created unique challenges within the last five years. These events have affected the travel sector of business more than any other industry. Monthly revenue declines of between 50% and 90% have been experienced by companies during this period. The year 2003 has been most difficult for Robin and Insight Vacations (S) Pvt Ltd. The International Herald Tribune (2003) quotes Lian Chia Liang at J.P. Morgan Chase in Singapore as saying that the [Singapore] economy would not grow any faster than 0.9 percent in 2003. This is consistent with the government%<p> <small> <a href="http://russell-davison.blog.co.uk/2006/09/21/entrepreneur_interview~1146692/#comments">Comments</a> </small> </p>tag:russell-davison.blog.co.uk,2006-09-20:/2006/09/20/entrepreneur_interviews~1144763/russell-davison2006-09-20T18:39:12+02:002006-09-20T18:39:12+02:00I originally wrote this article, “Entrepreneur interviews” in April 2004. I interviewed two entrepreneurs during Spring 2004. They were both ethnic minorities and owned the same type of business, but one was a female entrepreneur and the other was a male entrepreneur. The interviewees were asked questions regarding (a) entrepreneurial growth, (b) female entrepreneurs, and (c) ethnic entrepreneurs. The purpose of the interviews was to compare and contrast the two different people and to see how well their characteristics and experiences matched those published in entrepreneurial literature. Entrepreneurial growth plans for both interviewees contrasted each other. However, both entrepreneurs closely matched the findings of previous researchers. The female entrepreneur demonstrated caution, whereas the male entrepreneur displayed enthusiastic plans for growth; some of which had come to fruition. The male ethnic entrepreneur didn't conform to the literature view that ethnic entrepreneurs are more satisfied with lower wages than non-ethnic entrepreneurs. The female entrepreneur's approach to risk-taking and experience with support and role conflicts, closely followed the literature view. She had good support from her spouse, was a conservative risk-taker and the satisfaction she received from running her business had a positive impact on her family life. This contrasted with the male entrepreneur receiving support from friends, taking moderate risks and spending only half the week nights with his spouse and family. The interviewee responses to questions associated with ethnic minority entrepreneurs demonstrated that the passage of time, in a market of non-ethnic customers, erodes the ethnic minority characteristics, e.g. low wage acceptability, internal financing. In a period of within (say) a decade, the ethnic minority entrepreneur may absorb the culture of the host country, if working outside of the ethnic community. Both interviewees broadly conformed to the views of the entrepreneurial literature regarding ethnic minorities. They both started businesses in the service sector and they both chose a profession that they had prior experience in. However, whilst the literature supports the view that ethnic minority finance for start-up is usually internally sourced, only the female entrepreneur was self-funded. <strong> Introduction</strong> I interviewed two entrepreneurs during April 2004. The topics of discussion were limited to entrepreneurial growth, female entrepreneurs and ethnic entrepreneurs. Both entrepreneurs owned beauty salons and were ethnic minorities. Amy was female and was a hairdresser in Singapore. Cedric was in Malaysia. Amy was originally from Malaysia, but had settled with her husband in Singapore a few years ago. She had run a small beauty parlour, for almost 2 years, within a condominium block and had a staff of three. Cedric emigrated from Syria in 1984 and started his business 20 years ago. He had 30 employees and leased 2 retail units to provide his service of hairdressing, massage and spa therapy. <strong> Entrepreneurial growth</strong> The two entrepreneurs were asked the two questions of how they viewed the growth of their business and what their thoughts were on retaining business earnings versus making personal financial withdrawals. Both entrepreneurs had very different attitudes to growth. <strong>Growth plan</strong> Amy leased a small (200 square feet) unit from a condominium owner. She had been in business for almost 2 years. Her immediate goal was to increase the utilization of her current resources of space and labour. She had no immediate plans to grow t<p> <small> <a href="http://russell-davison.blog.co.uk/2006/09/20/entrepreneur_interviews~1144763/#comments">Comments</a> </small> </p>tag:russell-davison.blog.co.uk,2006-09-19:/2006/09/19/concepts_of_entrepreneurship~1140472/russell-davison2006-09-19T13:42:52+02:002006-09-19T13:42:52+02:00I originally wrote this article, &ldquo;Concepts of entrepreneurship&rdquo; in March 2004.<br> <br> Entrepreneur traits, creativity, innovation, business planning and growth management are five of the main concepts of entrepreneurship. Lists of characteristics common to entrepreneurs have been published by many authors but others suggest that previous experiences are more important. Entrepreneurial creativity requires a paradigm shift and there are many techniques available to help the entrepreneur to see things in a different perspective, to come up with new ideas. Innovation involves implementing newly created ideas and the process can be classified as invention, extension, duplication and synthesis. Strategic planning is used to assess the entrepreneur's position in external/internal environments, identify key success factors/competencies and to implement a strategy. Finally, the issue of growth management requires the entrepreneur to settle on what size of company he is happy with, how much direct control is afforded to him and how entrepreneurial spirit can be retained in a growing business.<br> <br> <strong>ENTREPRENEUR TRAITS</strong><br> <br> Many authors have published lists of characteristics that they consider to be displayed by entrepreneurs. Cunningham and Lischeron (1991) have grouped these contributions into six schools of thought. They classify these as the; "Great Person", Psychological, Classical, Management, Leadership and Intrapreneurship schools of thought.<br> <br> <strong>"Great person"</strong> - Born entrepreneurs, e.g. Fords, Rockefeller, Trump.<br> <strong>Psychological -</strong> Entrepreneurial personality, behaviour developed over time.<br> <strong>Classical - </strong>Entrepreneurial key factors are innovation and creativity.<br> <strong>Management - </strong>Entrepreneurs can be developed or trained in the classroom.<br> <strong>Leadership - </strong>Attract people to support a vision and transform it into reality.<br> <strong>Intrapreneurship - </strong>Encouraging people to work in semi-autonomous units.<br> <br> However, much criticism is levelled at these theories because many of the characteristics are not unique to entrepreneurs and can be found in successful managers and executives. Liles (1974:43) proposes that "certain kinds of experiences and situational conditions - rather than personality or ego - are the major determinants of whether or not an individual becomes an entrepreneur" and Bailey (2003) questions whether entrepreneurs possess different characteristics or whether they are merely products of unique situational factors. This view is also supported by O'Neile (1989), who affirms that the entrepreneur is a "product of his historical and environmental circumstances." The choice to become an entrepreneur must be influenced by events that led to the decision, claims Brockhaus and Horwitz (1986). They suggest that previous experience has an effect. These previous experiences could be positive, such as role models and education, or they could be negative displacements. Refugees and migrants may choose entrepreneurship if gaining employment is difficult. Job dissatisfaction or job loss may be other stimuli to select entrepreneurship.<br> <br> <strong>CREATIVITY</strong><br> <br> Entrepreneurship can be partly described as a combination of creativity followed by innovation, where creativity is the act of 'thinking' new things, coming up with ideas and innovation is &#<p> <small> <a href="http://russell-davison.blog.co.uk/2006/09/19/concepts_of_entrepreneurship~1140472/#comments">Comments</a> </small> </p>tag:russell-davison.blog.co.uk,2006-09-10:/2006/09/10/control_valve_seismic_analysis~1112612/russell-davison2006-09-10T11:12:50+02:002006-09-18T14:51:34+02:00 <p><img src="http://i9.tinypic.com/44s19jb.jpg" alt="Russell Davison" title="Russell Davison">I was asked to carry out this 16&rdquo; angle control valve seismic analysis for one of the world&rsquo;s leading engineering companies.</p> <p><strong>1.0 Summary of findings</p> <p>2.0 Introduction</p> <p>3.0 Identification of susceptible features to be analysed</p> <p>3.1 Body studs</p> <p>3.2 Area behind outlet flange</p> <p>4.0 Identification of operational loads </p> <p>4.1 Pressure of the line fluid</p> <p>4.2 Tightening of the body stud nuts</p> <p>4.3 Mass of the valve, actuator and bonnet</p> <p>5.0 Calculations</p> <p>5.1.0 Stresses imposed on the body studs by the action of operating loads and seismic acceleration, along the horizontal axis<br>5.1.1 Stresses caused by the hydrostatic end thrust or gasket seating<br>5.1.2 Bending stress due to the actuator<br>5.1.3 Bending stress due to the bonnet<br>5.1.4 Bending stress due to the body<br>5.1.5 Direct stress due to the actuator weight<br>5.1.6 Direct stress due to the bonnet weight<br>5.1.7 Direct stress due to the body weight<br>5.1.8 Direct stress due to the actuator thrust<br>5.1.9 Summation of stresses</p> <p>5.2.0 Stresses imposed on the body studs by the action of operating loads and seismic acceleration, along the vertical axis<br>5.2.1 Stresses caused by the hydrostatic end thrust or gasket seating<br>5.2.2 Direct stress caused by the body under the influence of acceleration due to gravity plus seismic effects<br>5.2.3 Direct stress caused by the actuator under the influence of acceleration due to gravity plus seismic effects<br>5.2.4 Direct stress caused by the bonnet under the influence of acceleration due to gravity plus seismic effects<br>5.2.5 Direct stress due to the actuator thrust<br>5.2.6 Summation of stresses</p> <p>5.3.0 Stresses imposed on the area behind the outlet flange by the action of operating loads and seismic acceleration along the horizontal axis<br>5.3.1 Longitudinal stress caused by the internal pressure<br>5.3.2 Bending stress due to the actuator<br>5.3.3 Bending stress due to the bonnet<br>5.3.4 Bending stress due to the body<br>5.3.5 Direct stress due to the actuator weight<br>5.3.6 Direct stress due to the bonnet weight<br>5.3.7 Direct stress due to the body weight<br>5.3.8 Direct stress due to the actuator thrust<br>5.3.9 Summation of stresses</p> <p>5.4.0 Stresses imposed on the area behind the outlet flange by the action of operatingloads and seismic acceleration along the vertical axis<br>5.4.1 Longitudinal stress caused by the Internal pressure<br>5.4.2 Direct stress caused by the body under the influence of gravity and seismic effects<br>5.4.3 Direct stress caused by the bonnet under the influence of gravity and seismic effects<br>5.4.4 Direct stress caused by the actuator under the influence of gravity and seismic effects<br>5.4.5 Direct stress due to the actuator thrust<br>5.4.6 Summation of stresses</p> <p>6.0 Results</p> <p>1.0 Summary of findings</strong> </p> <p>The 16" angle control valve will perform it's intended duty during an earthquake having a seismic acceleration of 0.81g in the horizontal direction, and during an earthquake having a seismic acceleration of 0.81g in the vertical direction. There will be no rupture of the valve body nor failure of the studs at the valve body/ bonnet joint.</p> <p><strong>2.</strong> </p> <p> <small> <a href="http://russell-davison.blog.co.uk/2006/09/10/control_valve_seismic_analysis~1112612/#comments">Comments</a> </small> </p>tag:russell-davison.blog.co.uk,2006-08-05:/2006/08/05/case_study_magazine_system_for_robot_ass~1015513/russell-davison2006-08-05T12:04:40+02:002006-08-26T12:12:47+02:00 <p>This is a design proposal that I was asked to carry out for a Swedish world leading manufacturer of compressors, generators, construction and mining equipment, industrial tools and assembly systems. They required a magazine system to present end-pieces for the pre-assembly of pneumatic cylinders.<br><img src="http://i1.tinypic.com/23qxpcl.jpg" alt="Russell Davison" title="Russell Davison" align="middle"><br>The second stage for the robot assembly of pneumatic cylinders involves the sub-assembly of end-pieces and half-pistons. End-pieces need to be handled by a magazine system because they are too large for conventional vibratory feeders.  A magazine system is required at the pre-production facilities that is a scaled-down version of the future production system, within budget limitations.  The cost of the system is split between the fixed cost for the transfer of parts to the robot and the variable cost of end-piece storage.  The variable storage cost is proportional to the capacity of the magazine system. There is also an indirect labour cost for the filling and transport of magazines, in addition to the equipment material cost. The prototype can have the same transfer device as the production model, but with a smaller capacity.</p> <p><strong>MAGAZINE FILLING</strong></p> <p>The only economical method of magazine loading is to fill them at the point of final manufacture. This is because the time taken to insert a part into a magazine can approach the time taken to insert it into the part-built assembly.  Nevertheless, end-pieces have to be transported from manufacture to assembly and magazines are the best way of doing this, whilst also giving protection to the surface finish.</p> <p><strong>MAGAZINE CAPACITY</strong></p> <p>The capacity of the magazine is as large as possible to achieve the minimum number of journeys from manufacturing to assembly during the shift.  If demand for each cylinder diameter is equal then the magazine must contain in excess of sixty parts for a refill only once a shift.  A single vertical stack magazine would be in excess of three metres high. It is therefore proposed that a number of units should be combined to form one magazine. Three magazines of twenty end-pieces seems reasonable.<br><strong><br>PROPOSED SYSTEM</strong></p> <p>The system shown is one method of end-piece distribution. The illustration shows one magazine to store one style of end-piece.  The production version for the Swedish manufacturing plant would have three magazines per end-piece, each behind the another. </p> <p> <small> <a href="http://russell-davison.blog.co.uk/2006/08/05/case_study_magazine_system_for_robot_ass~1015513/#comments">Comments</a> </small> </p>tag:russell-davison.blog.co.uk,2006-06-30:/2006/06/30/software_aid_to_product_design_for_robot~922645/russell-davison2006-06-30T09:37:16+02:002006-06-30T09:37:16+02:00 <p>I originally presented this article, "A Software Aid to Product Design for Robot Assembly", as a guest speaker at an <strong>I.Mech.E. Congress on Automotive Technology</strong> ...</p> <p><strong>INTRODUCTION</strong></p> <p>Original work by industrial researchers into classifying and coding parts for automatic parts handling, more than 30 years ago, led to considerations of good design features for automatic handling. Further research work resulted in a classification and coding system for manual handling, manual insertion and automatic insertion. This work culminated in the production of assembly system designer guidelines and these were later converted to computer software package to help product designers in the Design for Assembly process. With the increasing interest in the use of industrial robots for assembly, an obvious extension to the work on product design was the development of appropriate classification and coding systems for assembly robots and the translation of this into a user friendly computer based system.</p> <p><strong>PRODUCT DESIGN FEATURES FOR VARIOUS FORMS OF ASSEMBLY</strong></p> <p>There are inherent design rules for all forms of assembly and these are independent of the assembly process being used. There are other rules which are process dependent. The more important considerations are:</p> <p>Number of Parts:- For all forms of assembly, reducing the part count, through considering the potential redundancy of every part, leads to a reduction in assembly and component manufacturing costs.</p> <p>Parts Handling:- A further example of a common design requirement is for parts handling where, although manual handling is completely different to automatic handling, both benefit from an increase in the symmetry of a part. Similarly, both methods cannot easily accommodate minor asymmetrical features, nesting and tangling parts, very small or large parts, etc. As a result of this commonality, features which allow a part to be automatically handled easily are invariably useful for manual assembly and, in general terms, unless there is a significant manufacturing cost penalty, parts can always be designed for automatic handling.</p> <p>Parts Insertion:- The requirements for the various types of assembly vary significantly for some insertion operations. For manual handling, the emphasis is on access and sighting. For automatic assembly, the main features are alignment, ease of insertion and stability after insertion. An additional potential problem is the direction of insertion for robotic assembly. For fastening operations, regardless of assembly method, the most economic operations use integral fasteners and the most expensive require threaded fasteners.</p> <p>Parts Gripping:- In manual and automatic assembly (ignoring the features already mentioned related to size), gripping doesn’t create technological or economic problems. In robotic assembly, however, gripping features can be very significant and parts should be designed so that the least number of different grippers are required. This reduces costs and often reduces non-productive assembly time.</p> <p>Assembly sequence:- The optimum sequence of assembly is very much dependent upon the type of assembly. For single worker assembly, the sequence of assembly is not important and it’s often determined by operator preference. In manual line assembly, sequence is controlled by line balancing considerations. In automatic assembly, sequence is related to the basic logic of the equipment and is controlled by the quality and, under some circumstances, the cost of the parts to be assembled. The sequence of assembly is determined by gripper requirements in single station robotic assembly, where the emphasis is on reducing significant non-productive time, such as either gripper changing or turret indexing.</p> <p><strong>ASSEMBLY ALTERNATIVES</strong></p> <p>In manual assembly, the two categories are single worker and line, with many variations incorporating features of both methods. It is generally not too difficult to identify the most appropriate form of assembly.</p> <p>For automatic assembly, the choice of equipment is limited and selection is based on the number of parts, cost and component quality. Again, it is not difficult to identify the most appropriate equipment.</p> <p>In single-station robotic assembly however, the selection of the most appropriate equipment is more difficult. There are many assembly robot types with different characteristics. Additionally, there are many parts handling possibilities and various gripper options. Although basic design for robotic assembly is essentially independent of the particular assembly cell configuration, both the product designer and system designer need some help to evaluate the performance and economics of alternative systems. Software applications have been developed for robotic assembly to serve both these functions.</p> <p>Firstly, the product design is analysed by investigating its operation sequence relationship, handling features, gripping features and its insertion features. The user is asked to configure a system by specifying the robot to be used. The cost and performance specification for three popular assembly robots is built into a robot data file and these can be increased by the user at any time. The software application determines the most appropriate assembly sequence, based on interdependencies and the type of robot to be used. It then evaluates various parts feeding options. These options are based on feeder characteristics built into the system and they can be increased to include new types of automatic feeders.</p> <p>The software application offers re-design possibilities to reduce the handling cost, where only expensive feeding methods can be used or when only manual handling is possible. If the robot type is unsuitable, due to lack of capability, then this is reported and the application user can either modify the robot data file, enhancing the robot specification, or select another robot. If the number of grippers required is excessive then various re-designs for easier gripping are proposed. The application also takes into account existing equipment utilisation. This is important because greater utilisation reduces the assembly cost.<br> <strong><br> CONCLUSIONS</strong></p> <p>The product and system design software application is a useful tool for evaluating robotic assembly. It can be modified and extended to reflect advancements in robots, feeders and grippers. It gives a quick evaluation of the suitability of a product’s design and determines the effect of changing assembly system parameters. These tasks could be done manually, using data sheets, but it is time consuming because of the large number of permutations of the various equipment types. </p> <p> <small> <a href="http://russell-davison.blog.co.uk/2006/06/30/software_aid_to_product_design_for_robot~922645/#comments">Comments</a> </small> </p>tag:russell-davison.blog.co.uk,2006-06-29:/2006/06/29/flexible_assembly_of_automotive_componen~920755/russell-davison2006-06-29T14:29:50+02:002006-06-29T14:29:50+02:00 <p>I originally presented this article, "The Flexible Assembly of Automotive Components", as a guest speaker at an <strong>I.Mech.E. Congress on Automotive Technology</strong> ...</p> <p>There is a requirement for a special kind of system to assemble products required in modest volumes with a degree of variety. A system which is as cost effective and efficient as hard automation, whilst providing the flexibility of manual assembly, is called a flexible assembly system. Within such a system, certain product parts may be required at a different rate to other parts. Some operations may require the flexibility and dexterity of a robot, or even manual labour. The resultant system would be a hybrid of many methods of assembly. This article recommends a technique to be used for the design of such a system, with the aid of a case study.</p> <p><strong>INTRODUCTION</strong></p> <p>The factory cost of a product is the addition of the manufacturing cost (e.g. casting, moulding, turning) and the assembly cost (e.g. manual, automatic, robotic). Industrial engineers continually seek new methods to reduce the factory cost of products. The current trend of exploiting cheap labour in developing nations, through “offshoring” creates a challenge for domestic manufacturers in the developed nations. Between 40 and 60 percent of the factory cost for many products is associated with the labour content. The majority of this cost is incurred during assembly. There are three reasons for this uneven split between labour costs in manufacturing and assembly.</p> <p>(i) Manufacturing operations are usually done by, or with the aid of, a machine, i.e. turning, milling, drilling, etc. The manufacturing systems designer does not have the wide choice of the assembly systems designer because some degree of mechanisation must be used. It is then a logical extension to further automate the manufacturing process to reduce labour costs.</p> <p>(ii) New processes have been developed which eliminate many manufacturing operations. Powder metallurgy is an example of such a process.</p> <p>(iii) Most products are designed to be assembled manually. This often means that components are of such a design that they cannot be handled by automatic feeders. Additionally, many assembly insertion operations are too complex to be automated.<br> <strong><br> THE DESIGN OF FLEXIBLE ASSEMBLY SYSTEMS</strong></p> <p>The assembly process has two constituent parts and these are; the handling of components and the insertion of components. The design features of a part must be examined to decide if it can be automatically handled automatically or if it must be handled manually or placed in magazines. Similarly, the insertion process must be analysed to decide what type of workhead is required.</p> <p>Various organisations have developed procedures that help the designer to estimate how easy it is to handle and orientate components by assigning a handling code to each part. The maximum feed rate and relative cost of the feeding method can then be estimated from this code. The parts which would require expensive automatic feeders or which could not be fed at the required feed rate can be identified. These parts must then be handled manually or in magazines/pallets. Additionally, certain parts cannot be handled automatically because they have other bad feeding qualities, e.g. they may be flexible or too light. The previously mentioned estimation systems also help the system designer to forecast the relative cost of the workhead required to insert a part into a part-built assembly. Those operations which require a complex path of insertion, or a large thrust, require more expensive workheads than for simpler operations. A list of parts (with their associated automated handling codes) and a list of operations (with their allocated automatic insertion codes) can be constructed from the preceding information.</p> <p>If the product parts are listed in order of increasing handling difficulty levels then the most economical method of feeding a part to the workhead can be determined. Parts with low handling difficulty levels are fed by conventional vibratory feeders and, as the difficulty level increases, specially designed feeders/magazines/pallets/manual handling are used. The relationship between the handling difficulty level and the type of feeder to be used depends upon the required return on investment for the equipment.</p> <p>The insertion operations can also be listed in order of insertion difficulty levels to determine the most economical method of insertion of a part into a part-built assembly. Greater difficulty levels can mean that the equipment is more expensive and, for assembly robots, more degrees of freedom are required for an insertion operation. If the difficulty level is too high then it’s necessary to employ manual workers for some operations.</p> <p>When an assembly system is designed for a new product, the cost of parts handling and insertion can be reduced through re-design of the product. It’s usually not viable for an existing product to be re-designed, because of the tooling modification cost in the manufacture of the parts. Inevitably, therefore, the most economical method of assembly is limited to the existing product design, without design efficiency improvements.</p> <p>The assembly handling and insertion codes determine which feeding method and insertion device are most appropriate for each part and operation. The part-built assembly has to be transported to each workstation between operations. This will either be synchronous or non-synchronous motion. Synchronous machines are generally less expensive than non-synchronous types, but they are limited by how many parts can be assembled on one machine. This is due to downtime and the space available.</p> <p>It is desirable to construct a product from as many sub-assemblies as possible to achieve a high overall efficiency of the assembly system. These sub-assemblies should be common to all product styles, within the family of products. The variety can then be created in the final assembly of the product. If this approach is adopted then sub-assemblies will be required at a rate which is enough to justify the use of automatic indexing machines having dedicated workheads. The output from these machines can then be sent to the final assembly line via free transfer lines, to create a buffer stock of sub-assemblies. The buffer stock is necessary to minimise the effect of any indexing machine downtime. </p> <p> <small> <a href="http://russell-davison.blog.co.uk/2006/06/29/flexible_assembly_of_automotive_componen~920755/#comments">Comments</a> </small> </p>tag:russell-davison.blog.co.uk,2006-06-28:/2006/06/28/case_study_robot_assembly_of_pneumatic_c~917981/russell-davison2006-06-28T13:04:10+02:002006-06-28T13:15:42+02:00 <p>This is a manufacturing study that I was asked to carry out for a Swedish world leading manufacturer of compressors, generators, construction and mining equipment, industrial tools and assembly systems. The company wanted to create a database of observed operation times for robot assembly tasks.</p> <p><strong>INTRODUCTION</strong></p> <p>The robot assembly of the pneumatic cylinder has been analyzed using the video taken recently. Activity times were related to the digital clock display on the video. The object of analyzing the assembly process was to create a data base. Information could be extracted from this database to evaluate the robot assembly of other products manufactured by the client.</p> <p><strong>PNEUMATIC CYLINDER ASSEMBLY</strong></p> <p>There are fifteen parts used in the assembly of the pneumatic cylinder and some of these are actually sub-assemblies. All the parts are presented to the robot on a pallet, with the exception of the screws. The cover screws and piston rod screws are automatically handled by vibratory linear feeders. The cycle time for the complete assembly is 166 seconds. This is substantially longer than predicted by academic estimation methods.</p> <p>The speed of the robot is set at 60 percent of the maximum. An electric current in excess of that tolerated by the drive motor circuitry, at 100 percent, makes this action necessary. This high power consumption, at start-up, is caused by the mass of the turret being approximately five times that of a conventional gripper. The robot manufacturer is replacing the relevant circuitry to allow full speed of the robot. Additionally, they have modified the feedback circuit to compensate for the larger mass. The robot programmer estimates that an increase in speed, from 60 percent to 100 percent, would provide a reduction in the cycle time of no more than 20 percent. The activity times obtained from the current analysis are used for the purpose of design for robotic assembly, and the evaluation of the client’s other products.</p> <p><strong>SYNTHESIS OF ROBOTIC ASSEMBLY TIMES</strong></p> <p>The time taken to assemble a part by the robot has four periods :</p> <p>1) The movement of the gripper from the previous assembly position to above the current part to be assembled.</p> <p>2) The picking up of the part.</p> <p>3) The movement of the part to above the place of insertion.</p> <p>4) The insertion, and subsequent release, of the part.</p> <p>The above time periods, when added together, make up the basic operation time for a single activity.</p> <p><strong>RESULTS OF THE STUDY</strong></p> <p>The total assembly time for the pneumatic cylinder is broken down into 54 steps to quantify the 4 constituent periods in each activity. The time study sheet is shown later in this article. From the time study sheet, a basic operation time of eight seconds is derived. It can be seen from the table that this basic operation time is equally divided between the four constituent periods. Notable deviations from the basic operation time are :</p> <p>End-piece - The end-piece is used to form a sub-assembly with the half -piston. There is no insertion time for this part because it is integrated with the half-piston.</p> <p>Cover Screw - There is a 50 percent increase in the basic operation time for this part. It is caused by the extra time involved with screw fastening and the transportation distance between the linear feeder and the work fixture.</p> <p>Piston Rod - A significant increase in the basic operation time for this part is due to the additional operation of 'knocking down' the piston rod after insertion. This is necessary because of the technique used to lift this part from the pallet.</p> <p>Piston Rod Screw - A 50 percent increase in the basic operation time is caused by the screw fastening operation and the transportation time from the linear feeder to the work fixture.</p> <p>Completed Cylinder - The gripper is in an adverse position from the previous operation and this increases the operation time.</p> <p><strong>PREDICTION OF CYCLE TIME FOR THE ROBOT ASSEMBLY OF THE PNEUMATIC CYLINDER</strong></p> <p>The cycle time for the robot assembly of the pneumatic cylinder is predicted by using a basic operation time, multiplied by a factor.</p> <p>assembly time = basic operation time * assembly process factor<br> where,<br> basic operation time = 8 seconds<br> assembly process factor = 1.0 for straightforward insertion<br> 1.5 for screw fastening operations<br> 1.5 for long parts requiring two insertions</p> <p>Using the above approximations, a cycle time of 164 seconds is predicted. This is within one percent of the actual time of 166 seconds. It is not suggested that such a simple method could always achieve this accuracy. However, in the present case, the predictions for 9 out of 10 parts are within plus/minus 1 sec.</p> <p>PART ACTUAL PREDICTED DEVIATION OUTSIDE<br> DESCRIPTION TIME TIME 1 SECOND<br> CYLINDER BARREL 7 8 NONE<br> END-PIECE 5 *4 * NONE<br> HALF-PISTON 7 8 NONE<br> COVER SCREW 48 48 NONE<br> PISTON ROD 13 12 NONE<br> HALF-PISTON 8 8 NONE<br> PIN ROD SCREW 12 12 NONE<br> END-PIECE 8 8 NONE<br> COVER SCREW 12 12 NONE<br> COMPLETED CYLINDER 10 8 2 SECONDS<br> 166 164<br> <strong>NOTE</strong></p> <p>The predicted time of 4 seconds for the end-piece allows for the fact that it is not inserted into the part-built assembly. This part forms a sub-assembly with the half-piston.</p> <p>There is a negligible amount of time lost due to gripper changing. The turret is indexed during movement from one operation to the next. A typical programming chart for a component is given at the end of this article and it shows that the basic assembly operation takes 8 program steps. Additional steps are required for screw fastening.</p> <p><strong>TIME STUDY FOR ROBOT ASSEMBLY OF PNEUMATIC CYLINDER</strong></p> <p>0:01 Gripper above cylinder barrel<br> 0:02 Pick up cylinder barrel<br> 0:05 Cylinder barrel above fixture<br> 0:07 Release cylinder barrel<br> 0:10 Gripper above end-piece<br> 0:14 Gripper above half-piston<br> 0:15 Insertion of end-pieces and half-piston completed<br> 0:17 Half-piston and end-piece above barrel<br> 0:19 Release half-piston<br> 0:21 Arm 2 above cover screw<br> 0:24 Pick up cover screw<br> 0:26 Cover screw above barrel<br> 0:34 Arm 2 above cover screw<br> 0:36 Pick up cover screw<br> 0:38 Cover screw above barrel<br> 0:46 Arm 2 above cover screw<br> 0:48 Pick up cover screw<br> 0:50 Cover screw above barrel<br> 0:58 Arm 2 above cover screw<br> 1:00 Pick up cover screw<br> 1:02 Cover screw above barrel<br> 1:09 Gripper above piston rod<br> 1:11 Pick up piston rod<br> 1:14 Piston rod above fixture<br> 1:20 Completion of piston rod assembly to cylinder<br> 1:22 Gripper above half-piston<br> 1:24 Pick up half-piston<br> 1:26 Half-piston above fixture<br> 1:28 Completion of half-piston assembly to barrel<br> 1:30 Gripper above piston rod screw<br> 1:32 Pick up piston rod screw<br> 1:35 Piston rod screw above fixture<br> 1:40 Completion of piston rod screw assembly to piston rod<br> 1:42 Gripper above end-piece<br> 1:44 Pick up end-piece<br> 1:46 End-piece above fixture<br> 1:48 Completion of end-piece assembly to barrel<br> 1:50 Gripper above cover screw<br> 1:52 Pick up cover screw<br> 1:55 Cover screw above barrel<br> 2:02 Gripper above cover screw<br> 2:04 Pick up cover screw<br> 2:07 Cover screw above barrel<br> 2:15 Gripper above cover screw<br> 2:17 Pick up cover screw<br> 2:19 Cover screw above barrel<br> 2:27 Gripper above cover screw<br> 2:29 Pick up cover screw<br> 2:32 Cover screw above barrel<br> 2:36 All cover screws inserted<br> 2:40 Gripper above barrel<br> 2:42 Pick up completed cylinder<br> 2:44 Completed cylinder above pallet<br> 2:46 Completed pneumatic cylinder in pallet</p> <p><strong>BASIC OPERATION TIME OF THE ROBOT</strong></p> <p> FROM PREVIOUS PICK MOVE TO INSERTION OPERATION<br> OPERATION UP PLACE OF AND TIME<br> TO ABOVE PART INSERTION RELEASE (SECONDS)<br> PART<br> 10) CYLINDER BARREL 1 1 3 2 007<br> 09) END-PIECE 3 2 0 0 005<br> 08) HALF-PISTON 2 1 2 2 007<br> 07) COVER SCREW 3 2 2 5 012<br> 07) COVER SCREW 3 2 2 5 012<br> 07) COVER SCREW 3 2 2 5 012<br> 07) COVER SCREW 3 2 2 5 012<br> 06) PISTON ROD 2 2 3 6 013<br> 05) HALF-PISTON 2 2 2 2 008<br> 04) PISTON ROD SCR 2 2 3 5 012<br> 03) END-PIECE 2 2 2 2 008<br> 02) COVER SCREW 3 2 2 5 012<br> 02) COVER SCREW 3 2 2 5 012<br> 02) COVER SCREW 3 2 2 5 012<br> 02) COVER SCREW 3 2 2 5 012<br> 01) COMPLETED CYLINDER 4 2 2 2 010<br> TOTAL 166<br> <img src="http://i5.tinypic.com/16094sj.jpg" alt="russelldavison001" title="russelldavison001"> </p> <p> <small> <a href="http://russell-davison.blog.co.uk/2006/06/28/case_study_robot_assembly_of_pneumatic_c~917981/#comments">Comments</a> </small> </p>tag:russell-davison.blog.co.uk,2006-06-27:/2006/06/27/case_study_robot_assembly_of_pneumatic_v~915124/russell-davison2006-06-27T12:35:17+02:002006-07-27T07:55:03+02:00 <p>This is a quick feasibility study that I was asked to carry out for a Swedish world leading manufacturer of compressors, generators, construction and mining equipment, industrial tools and assembly systems. They wanted a swift appraisal of the economics for the robot assembly of their pneumatic valves.</p> <p><strong>INTRODUCTION</strong></p> <p>The client company has committed to capital investment in a two-armed robot for the assembly of its range of pneumatic cylinders at one of its Swedish manufacturing plants. The robot will not be fully utilised and another product is required to economically justify the installation.</p> <p>The manufacturing plant currently assembles two product families :</p> <p>1) Pneumatic cylinders<br> 2) Pneumatic valves</p> <p>The feasibility of assembling a model of pneumatic valve is investigated for the client company.<br> <strong><br> VOLUME REQUIREMENTS OF THE SPECIFIC PNEUMATIC VALVE MODEL</strong></p> <p>The pneumatic valve annual production volume is 30 000 units. The valve is currently assembled manually and the client company assumes that demand for the valve will increase to 40 000 within 2 years. Three workers are currently required for product assembly. The product has a total of 63 separate parts, of which, 31 are unique parts.</p> <p><strong>MANUAL ASSEMBLY</strong></p> <p><img src="http://i7.tinypic.com/212egj6.jpg" alt="Russell Davison" title="Russell Davison"><br> The manual assembly of the valve has been studied to create individual times for the 97 operations. The manual assembly worksheet, shown below, gives the sequence of operations and their corresponding operation times. The worksheet shows that the cycle time for the complete assembly is 389 seconds. One worker can assemble 11 786 valves in one year, with single shift working at a labour efficiency of 70 percent :</p> <p>225 working shifts per annum (single shift working)<br> = 5 940 000 working seconds per annum (440 minutes / shift)<br> = 4 158 000 working seconds per year at 70 percent labour efficiency<br> = 10 689 units assembled per annum. .</p> <p><strong>ROBOT ASSEMBLY</strong></p> <p>Certain assembly operations can be executed by the robot without a re-design of the pneumatic valve. The assembly sequence for the robot assembly is given at the end of this article and an estimate for the robot capital expenditure is :</p> <p>(a) Cost of the robot and controller = 50 000 euros.</p> <p>(b) Turret and eight grippers = 5 000 euros</p> <p>(c) Fixture number 32 = 3 000 euros, fixture number 33 = 2 000 euros, fixture number 34 = 2 000 euros, fixture number 35 = 3000 euros, fixture number 36 = 2 000 euros, fixture number 37 = 500 euros, fixture number 38 = 500 euros, fixture number 39 = 2 000 euros</p> <p>(d) Arm-2 0-ring tools (6 off), including tool holder = 1 800 euros. Arm-2 screwdriver bit and friction screwdriver bit = 200 euros.</p> <p>(e) Greasing station = 2 000 euros</p> <p>( f) Labelling station = 5 000 euros</p> <p>(g) Cleaning station = 2 000 euros</p> <p>(h) Eight vibratory linear feeders at 3 000 euros each = 24 000 euros</p> <p>Total = 105 000 euros</p> <p><strong>CYCLE TIME</strong></p> <p>It is estimated that the cycle time for the robot and manual assembly of the valve would be 456 seconds. Using this estimate, one robot can assemble 5210 valves in one year, with single shift working at a robot efficiency of 80 percent :</p> <p>225 working shifts per annum (single shift)<br> = 5 940 000 working seconds per annum (440 minutes/shift)<br> = 4 752 000 working seconds per year at 80% robot efficiency<br> = 10 421 units assembled per year (single shift)</p> <p>The robot can assemble approximately the same number of products per year as one worker, considering single shift working. However, certain operations (using the existing product design) must be executed manually.</p> <p><strong>ANNUAL COST SAVINGS</strong></p> <p>The annual cost saving of using the robot is one worker per year. If the annual cost of an operator is 50 000 euros per year (including taxes, social charges, pension contributions, overhead contribution, etc.) then the cost saving would be approximately 50 000 euros per year.</p> <p><strong>PAYBACK PERIOD</strong></p> <p>The payback period for using the robot is 2 years, for the assembly of 10 421 units per year. </p> <p><strong>VALVE SPECIFICATIONS</strong></p> <p>If the valve is to be re-designed then it must have the following performance characteristics :</p> <p>(a) It must achieve a flow rate of 2.2 litres per second for 10 000 000 cycles of operation, without leakage from port to port.</p> <p>(b) The upper sealing gasket must not drop off when the body sub-assembly is transported between operations.</p> <p>(c) The inner sleeve 0-rings must be stable during assembly of the inner sleeve sub-assembly to the valve body.</p> <p>(d) The activation time of the unit must be better than 0.02 seconds.</p> <p>(e) The operating air pressure for the double acting valve should be less than 1.2 kg/cm2 and less than 2.5 kg/cm2 for the spring return valve.</p> <p>(f) The customer should have the option of achieving flow rates between 0 and 50 percent of the maximum and between 50 and 100 percent of the maximum, using a convenient design feature.</p> <p><strong>RECOMMENDATIONS FOR A RADICAL RE-DESIGN OF THE PNEUMATIC VALVE TO REDUCE THE NUMBER OF PARTS IN THE ASSEMBLY</strong></p> <p>The following design changes are recommended to reduce the cost of the assembly of the pneumatic valve :</p> <p>(1) Eliminate the choke screw housing (6) by providing an internal thread in the valve body, where the choke screw housing sub-assembly is currently situated. This would involve the use of a choke screw and O-ring only, thus eliminating two parts. .</p> <p>(2) Eliminate the gasket (2) and top cover (23) by moulding the airway into the integral body and top cover. This would eliminate two parts but would require the bodies to be stocked in two styles to accommodate single acting and double acting valves.</p> <p>(3) Eliminate the piston sleeve (9) by reducing the bore of the body at this point so that the piston is guided by the body, instead of the sleeve.</p> <p>(4) Eliminate the three sleeves (9), (12), (14) and integrally mould the three sleeves as one part.</p> <p>(5) Eliminate the piston by integrally moulding it with the spool piece, for single acting valves.</p> <p>(6) Eliminate the spool piece O-rings / sealing rings and locate them on the spool piece sleeves.</p> <p>(7) Eliminate one end piece and integrate it with the valve body.</p> <p>(8) Eliminate the indicator and integrate it with the spool piece.</p> <p>(9) Eliminate the label and print it directly onto the valve. </p> <p>(10) Eliminate the cover screws and incorporate (a) a bayonet fitting or, (b) a screw thread between the body and end cover.</p> <p>(11) Eliminate the short spring by changing the following design features of the long springs :<br> (a) spring wire gauge<br> (b) number of turns per inch<br> (c) spring material<br> (d) external diameter of spring</p> <p><strong>CONSIDERATIONS FOR THE RE-DESIGN OF THE PNEUMATIC VALVE</strong></p> <p>There are many factors that must be considered when re-designing the pneumatic valve for assembly. The effect of changing one design feature of a part may have an effect on the design of the other parts. The performance of the valve can be reduced by adverse design changes, or there may be an increase in the manufacturing costs of the product parts, due to new tooling costs. A number of factors must be considered when the re-designed valve is being evaluated :</p> <p>(1) A capital investment has been made by the client company in mould tooling for the valve body. If other part features are to be integrated within the body, or if the body is to be split into more than one component, then there will be an investment required for the new mould tooling.</p> <p>(2) If the choke screw housing feature is to be integrated within the valve body then the body tooling modification cost, and the scrapped choke screw housing tooling cost, must be considered.</p> <p>(3) The assembly of the O-ring seals to the spool piece presents the problem of expanding the O-rings over the part and then allowing them to contract into the o-ring groove. The task can be simplified by re-designing the joints between the spool piece sleeves. Unfortunately, the current design of joints has been carefully chosen to avoid the possibility of an O-ring passing over a joint between two sleeves. It would be very difficult to achieve this same performance, so that the valve would operate for more than 3 000 000 cycles without a loss in performance.</p> <p>(4) The spool piece is surrounded by sleeves having a multitude of holes in them. It would be logical to eliminate the sleeves and to direct the flow of air from one port directly to another port. However, these sleeves are required to provide an even flow path around the spool piece to maintain the required flow rate. Larger ports could be moulded into the valve body, but this could cause the O-rings to be damaged as they passed over the ports.</p> <p>(5) The piston is guided by the piston sleeve. This piston guide design feature could be integrated within the valve body. The inside diameter of the piston guide must be such that the air pressure required to operate the valve is no greater than that already required. Additionally, it must still be possible to insert internal parts to the valve body. If the piston sleeve is integrated into one half of the body only, for spring return valves, then all of the parts associated with the spool piece can be inserted from one end of the of the valve. This option would, of course, require there to be two valve bodies for the product range.</p> <p>(6) The thrust from a new single spring must be such that it can overcome the action of the fluid pressure and the friction between the spool piece O-rings and the sleeves.</p> <p>(7) The sleeves are moulded as separate components because, as an integral part, it would be difficult to get the correct distribution of plastic in the mould. If the sleeve must be split for this reason then it would be advantageous to situate spool piece O-ring seals between the sleeves.</p> <p>(8) It must be impossible to inadvertently unscrew the choke screw out of the body. If the valve was to be re-designed so that the choke screw could be inserted into the body after assembly of the cover, or into a body with an integral top cover, difficulties may arise. If the choke screw can be inserted after the cover, or cover feature, then it could also be removed by screwing. The addition of a retaining part would be counter-productive and, therefore, a stamping operation would be more efficient. The tops of the choke screw holes would be deformed after insertion of the choke screw, thus retaining it.</p> <p>(9) During manual assembly of the spool piece sub-assembly to the valve body, special tools are required to assist the operator. The outside diameter of the sealing ring is much larger than the inside diameter of the spool piece sleeve. A special tool is required to contract the rings before insertion into the valve body. The operation is so complex that it may not be efficient to carry it out by a robot, in its current state of design.</p> <p>(10) The operation of inserting the spool piece sub-assembly into the valve body is so complex that it is not feasible for it to be done by the robot.</p> <p>(11) The piston and lip seal can only be inserted into the sleeve in one direction. This is because the lip of the seal has a larger diameter than the inside of the sleeve. The piston could be inserted in both directions if the seal was an O-ring.</p> <p>(12) If one of the end pieces were to be integrally moulded with the body then all parts could only be inserted into the body from one direction. The sealing of the indicator would create special problems. If the seal is inserted by the robot then it cannot be sufficiently located. Otherwise, the robot would not be able to assemble the seal. During movement of the indicator, the seal may be removed from its housing.</p> <p>(13) Integration of the top cover would make it impossible to change the routing of the signal air because the gasket would no longer be present.</p> <p>(14) The current pneumatic valve design currently has two springs to generate the required thrust.</p> <p>(15) The pin is required for the stability of the long spring, during operation.</p> <p>(16) For aesthetics, the top cover and end covers must be of aluminium, to give the impression of robustness to the product.</p> <p>(17) The dimensions of the inlet / outlet ports must be kept the same for compatibility with complimentary and substituted products.</p> <p><strong>MANUAL ASSEMBLY WORKSHEET</strong></p> <p>1 = Part identification number<br> 2 = Number of times that the operation is carried out consecutively<br> 3 = Two digit manual handling code<br> 4 = Manual handling time per part<br> 5 = Two-digit manual insertion code<br> 6 = Manual insertion time per part<br> 7 = Operation time in seconds (2) x [(4)+(6)]<br> 8 = Operation cost, centimes 0.4 x (7)<br> 9 = Figures for the estimation of the theoretical minimum number of parts</p> <p>_1 2 _3 ___4 _5 ___6 _____7 ___8 9<br> 23 1 30 01.95 00 01.5 003.45 01.38 1 PICK UP TOP COVER<br> 99 12.0 012.00 03.00 CLEAN THE TOP COVER<br> 30 1 88 06.35 33 05.0 011.35 04.54 PEEL OFF LABEL<br> 06 2 11 01.80 003.60 01.44 PICK CHOKE S. HOUSING<br> 05 2 03 01.69 30 02.0 007.38 02.95 PICK UP O-RING<br> 04 2 10 01.50 00 01.5 006.00 02.40 PICK UP CHOKE SCREW<br> AUTO. SCREW CHOKE<br> 07 2 03 01.69 30 02.0 007.38 02.95 PICK UP O-RING<br> 01 1 30 01.95 00 01.5 003.45 01.38 1 PICK UP VALVE BODY<br> 29 2 33 02.51 40 04.5 014.02 05.60 PICK UP BLANKING PC.<br> 01 1 98 09.00 009.00 03.60 TURN BODY UP/DOWN<br> 2 30 01.95 31 05.0 013.90 05.56 PICK UP CH. SCREW S/A<br> 02 1 38 03.34 43 07.5 010.84 04.34 INSERT GASKET<br> 1 02 02.5 002.50 01.00 INSERT COVER TO BODY<br> 19 1 10 01.50 001.50 00.60 PICK UP PISTON<br> 18 1 10 01.50 30 02.0 003.50 01.40 INS. LIP SEAL TO PISTON<br> PICK UP O-RING TOOL<br> 16 1 03 01.69 00 01.5 003.19 01.28 INSERT O-RING TO TOOL<br> 17 1 00 01.13 30 02.0 003.13 01.25 INS. SPOOL TO O-RING<br> PICK UP MIDDLE O-RING<br> 16 2 03 01.69 00 01.50 006.38 02.55 INS. O-RING TO TOOL<br> 17 2 00 01.13 30 02.00 006.26 02.50 INS. O-RING TO SPOOL<br> 15 3 03 01.69 44 08.50 030.57 12.23 SEAL RING TO SPOOL<br> 24 2 10 01.50 003.00 01.20 PICK UP INDICATOR<br> 20 2 03 01.69 30 02.00 007.38 02.95 INSERT O-RING TO IND.<br> 22 2 30 01.95 30 02.00 007.90 03.16 INSERT ENDPIECE<br> 09 2 10 01.50 003.00 01.20 PICK UP PISTON SLEEVE<br> 08 4 03 01.69 30 02.00 014.76 05.90 INS. 0-RING TO SLEEVE<br> 10 2 10 01.50 30 02.00 007.00 02.80 INS. SEAL TO SLEEVE<br> 12 2 10 01.50 30 02.00 007.00 02.80 INS. SEAL TO PISTON<br> PICK UP O-RING TOOL<br> 11 2 03 01.64 30 02.00 007.38 02.95 INS. O-RING TO SLEEVE<br> 1 10 01.50 00 01.50 003.00 01.20 SLEEVES TO FIXTURE<br> 14 1 00 01.13 001.13 00.45 PICK UP HALF SLEEVES<br> 13 1 03 01.69 30 02.00 003.69 INS. 0-RING TO HALF-SLV<br> 00 01.50 001.50 INSERT HALF PISTON<br> 1 00 01.13 001.13 PICK UP VALVE BODY<br> INS. TOOL TO VLV. BODY<br> 30 02.00 002.00 INSERT VALVE BODY<br> PICK UP O-RING TOOL<br> 13 1 03 01.69 30 02.00 003.69 INS. O-RING TO TOOL<br> 1 12 05.00 005.00 INS. O-RING TO VALVE<br> 1 10 01.50 30 02.00 003.50 INS. SLEEVE TO BODY<br> 1 10 01.50 30 02.00 003.50 INS. PISTON TO SLEEVE<br> 2 00 01.13 002.26 PICK UP END PIECE<br> 21 2 23 02.36 43 07.50 019.72 GASKET TO ENDPIECE<br> 2 02 02.50 005.00 ENDPIECE TO BODY<br> 25 8 11 01.80 00 01.50 026.40 INS. COVER SCREW<br> 8 92 05.00 040.00 16.00 FASTEN COV. SCREWS<br> 1 98 09.00 009.00 03.60 TURN VALVE BODY<br> 1 99 12.00 012.00 LUBRICATE VLV. BODY<br> PICK UP SPOOL TOOL<br> 1 00 01.13 31 05.00 006.13 PICK UP SPOOL PIECE<br> PUT TOOL DOWN<br> 26 1 00 01.13 02 02.50 003.63 INS. SPRING TO SPOOL<br> 27 1 00 01.13 02 02.50 003.63 INS. SPRING TO SPOOL<br> 28 1 10 01.50 02 02.50 004.00 INS. PIN TO SPRING<br> 1 00 01.13 00 01.50 002.63 INS. VALVE TO FIXTURE<br> 02 1 23 02.36 43 07.50 009.86 INS. GASKET TO BODY<br> 389.22</p> <p><strong>ASSEMBLY SEQUENCE FOR THE ROBOT ASSEMBLY OF THE PNEUMATIC VALVE, WITH MANUAL ASSISTANCE</strong></p> <p>Note - Operations marked with an asterisk (*) are carried out manually.</p> <p> (1) Pick up the cover (23) from the pallet and insert into fixture (32).<br> (2) Automatically clean the cover.<br> (3) Automatically feed and insert the label (30) to top cover.<br> *(4) Pick up the choke screw housing (6).<br> *(5) Pick up the O-ring seal (5) and insert onto choke screw housing.<br> *(6) Pick up the choke screw (4) and insert into the choke screw housing.<br> *(7) Fasten choke screw in choke screw housing by friction screwdriver.<br> *(8) Pick up O-ring seal (7) and insert into choke screw housing.<br> *(9) Pick up valve body (1).<br> *(10) Pick up gasket and assemble to valve body.<br> (11) Pick up valve body and insert into fixture (33).<br> (12) Automatically feed and insert the blanking piece (29) into the valve body.<br> (13) Rotate the body in the fixture by 180 degrees.<br> (14) Pick up the choke screw sub-assembly and insert into the valve body.<br> (15) Pick up the top cover and insert into the valve body.<br> (16) Automatically feed the piston (19) and insert into fixture (34).<br> (17) Automatically feed the lip-seal and insert into the piston.<br> *(18) Pick up O-ring tool.<br> *(19) Pick up O-ring (16) and insert onto O-ring tool.<br> *(20) Pick up spool piece (17) and insert into tool.<br> *(21) Insert O-ring into spool piece.<br> *(22) Pick up O-ring tool.<br> *(23) Pick up O-ring and insert into O-ring tool.<br> *(24) Pick up spool piece and insert into tool.<br> *(25) Insert O-ring into spool piece.<br> *(26) Pick up O-ring tool.<br> *(27) Pick up O-ring and insert into tool.<br> *(28) Insert O-ring into spool piece.<br> *(29) Pick up sealing ring (15) and insert onto spool piece.<br> *(30) Pick up end piece.<br> *(31) Pick up end piece gasket (21) and insert into end piece.<br> *(32) Insert end piece sub-assembly into magazine.<br> (33) Pick up end piece and insert into fixture (35).<br> (34) Automatically feed and pick up end piece O-ring (20) and insert end piece.<br> (35) Automatically feed and pick up indicator (24) and insert into end piece.<br> (36) Automatically feed the piston sleeve (9) and insert into fixture (36).<br> (37) Automatically feed the O-ring (8) and insert into piston sleeve.<br> (38) Automatically feed the lip-seal (10) and insert into piston sleeve.<br> (39) Automatically feed the sleeve (12) and insert into piston sleeve.<br> (40) Automatically feed O-ring (11) and insert into sleeve.<br> (41) Pick up piston sleeve and sleeve and insert into fixture (37).<br> (42) Automatically feed middle sleeve O-ring (13).<br> (43) Automatically feed middle sleeve (12) and insert into O-ring.<br> (44) Insert middle sleeve and O-ring into sleeve.<br> (45) Pick up the body and insert onto sleeves.<br> *(46) Insert O-ring into valve body.<br> (47) Pick up sleeve and piston sleeve and insert into valve body.<br> (48) Pick up piston and insert into piston sleeve.<br> (49) Pick up end piece and insert into valve body.<br> (50) Automatically feed end piece screw and insert into valve body.<br> (51) Fasten end piece screw into valve body.<br> (52) Rotate the valve body by 180 degrees.<br> (53) Lubricate the valve.<br> (54) Insert spool piece tool into body.<br> (55) Insert spool piece into body.<br> (56) Remove spool piece tool.<br> (57) Automatically feed and insert long spring (26) into spool piece.<br> (58) Automatically feed and insert short spring (27) into spool piece.<br> (59) Automatically feed and insert pin (28) into spring.<br> (60) Repeat operations 49 to 51.<br> (61) Pick up the valve and place onto the test station.<br> (62) Pick up the gasket (3) and insert into the valve body. </p> <p> <small> <a href="http://russell-davison.blog.co.uk/2006/06/27/case_study_robot_assembly_of_pneumatic_v~915124/#comments">Comments</a> </small> </p>tag:russell-davison.blog.co.uk,2006-06-26:/2006/06/26/robot_parts_1~912142/russell-davison2006-06-26T10:31:11+02:002006-07-27T08:09:05+02:00 <p>I originally published this article under the title, “The Presentation of Parts for Robot Assembly” in the <strong>book “Advances in Manufacturing Technology”</strong>, Kogan Page, London, ISBN 1.85091.3951 ...</p> <p><img src="http://i7.tinypic.com/212erls.jpg" alt="Russell Davison" title="Russell Davison"><br> The presentation of parts for robot assembly involves the selection of the correct parts handling devices and it influences the robot degrees of freedom required. The design of appropriate feeders is discussed, with an emphasis on their flexibility. A classification system is described that allows parts to be categorised by their design features and physical properties. The performance of an automatic parts feeder is shown to depend upon the design of the part that is being handled. A selection procedure is described that enables the correct handling device and robot configuration to be chosen for a particular application. An expert system is shown to be the best method of acquiring design information about the handle-ability of a part. A software package that simplifies the selection of parts feeders and robot configurations is described. The importance of knowledge transfer between industrialists and researchers, in defining relevant handling devices, is discussed. The development of an enhanced CAD system is the subject of a further publication.</p> <p><strong>INTRODUCTION</strong></p> <p>The presentation of parts to a robot presents some of the most difficult problems in robot assembly. Single cell robot assembly systems may assemble a complete product consisting of several parts. These parts have to be presented to the robot at the correct rate and in a known orientation, or a limited number of known orientations. The rate of supply of parts to the robot cell is seldom a problem because cycle times are usually long. The orientation of the part, at the exit of the parts feeding device, is critical because this influences many other factors. The orientation of a particular design of part at the feeder exit can be predicted using knowledge of handling device design. Parts are classified according to size, geometry, etc. so that feeding device performance can be qualified. Using a standard parts coding system, feeder performance can be matched with that required for a particular design of part. The orientation of the part, at the exit of the automatic feeder, can be predicted and the need for extra robot degrees of freedom can be determined. The presentation of parts for robot assembly is a complex problem and it’s best carried out using a software application.</p> <p><strong>PARTS PRESENTATION TECHNIQUES</strong></p> <p>A multitude of automatic feeders are available to handle a wide variety of parts. However, only a small proportion of these automatic feeders are economically viable for robot assembly. For robot assembly, an automatic parts feeder must have a high general-purpose content and a low special-purpose content, so that the flexibility of the robot is not compromised by the inflexibility of its feeders. The vibratory linear feeder has a low cost special-purpose feed track that is mounted on a general-purpose drive unit and frame. The device is very flexible because changeover is effected by removing the current feed track and replacing it with a feed track for the next part. The vibratory bowl feeder consists of medium cost special-purpose tooling that is mounted around the periphery of a general-purpose bowl. The feeder is generally inflexible and the time associated with part changeover makes it unsuitable for many applications with small batch sizes. The horizontal pallet transfer system has low cost special-purpose pallets that move into, and out of, the work zone by a general-purpose transfer system. Flexibility is achieved by using different pallet configurations or by simply changing the pallet contents. The 'Hitachi' type feeder works on a similar principle to the vibratory bowl feeder, with the special-purpose tooling being replaced by a vision system. Within certain geometrical and size limitations, this device is highly flexible; using a vision system to identify part orientations. The programmable belt feeder uses special-purpose pushers and gates, activated by a vision system or sensors, mounted above a general-purpose belt. Product changeover is achieved by using a different vision system computer program or by replacing the pushers and gates. </p> <p> <small> <a href="http://russell-davison.blog.co.uk/2006/06/26/robot_parts_1~912142/#comments">Comments</a> </small> </p>tag:russell-davison.blog.co.uk,2006-06-25:/2006/06/25/robot_parts_2~909437/russell-davison2006-06-25T10:09:22+02:002006-07-27T08:10:28+02:00 <p><strong>PARTS CLASSIFICATION FOR FEEDING</strong></p> <p><img src="http://i7.tinypic.com/212hh7c.jpg" alt="Russell Davison" title="Russell Davison"><br> It’s important to be able to classify or describe the features of a part so that particular part shapes can be identified. Firstly, a part can be classified according to it's basic shape, i.e. rotational or non-rotational. Each rotational or non-rotational part has a certain aspect ratio that allows it to be classified as being a disc, short cylinder, long cylinder, flat, long or cubic. Secondly, the amount of symmetry that a part possesses can be quantified. The amount of symmetry is determined by defining how often an orientation is repeated when the part is rotated through three mutually perpendicular axes. Thirdly, the amount of symmetry that a part possesses can be identified. The asymmetrical feature or features are those that cause the part not to have symmetry about an axis or axes. Fourthly, the bulk properties of a part can be identified to estimate the loss in performance of those feeders which deliver parts from bulk random orientation. Properties such as overlapping, tangling, nesting or stickiness reduce the feed rate and may even prevent feeding, depending upon the magnitude of the adverse property. Lastly, the physical properties of a part can preclude it from being handled by certain automatic feeders. Other properties, such as abrasiveness or a delicate surface finish, may cause problems with different feeder designs.<br> <strong><br> PERFORMANCE OF FEEDING DEVICES</strong></p> <p>Each robot assembly handling device has its own performance characteristics. A given device is able to handle a limited number of parts within a certain size range and geometry class. The orientation efficiency of a feeder, for parts with no adverse physical properties, is unimportant for robot assembly because the relatively long cycle time means that the demand rate for parts is low. The orientation efficiency for automatic feeders which sort out parts with adverse physical properties from bulk random orientation can be extremely low or zero if the adverse physical property is severe. Parts with severe adverse physical properties cannot be sorted from bulk random orientation and other methods of handling must be chosen. A typical solution to this problem is to present the part on a horizontal pallet transfer system. These handling devices are loaded manually or, preferably at the point of manufacture, using pick and place devices.</p> <p> <small> <a href="http://russell-davison.blog.co.uk/2006/06/25/robot_parts_2~909437/#comments">Comments</a> </small> </p>tag:russell-davison.blog.co.uk,2006-06-24:/2006/06/24/robot_parts_3~907166/russell-davison2006-06-24T10:47:28+02:002006-06-24T10:47:28+02:00 <p><strong>ROBOT ASSEMBLY HANDLING CHARTS</strong></p> <p>The required attitude of a part, on insertion, influences the choice of handling device and it also affects the number of robot degrees of freedom required. A particular feeding device, if it can handle the part under consideration, may be able to present a part in only one unique orientation or it may be able to present the part in a number of unique orientations. The orientation(s) of the part at the feeder exit are determined by considering the design of orientation tooling that is required. For vision system controlled feeders, knowledge is required of whether or not the part's orientation can be deduced by the vision system. If the attitude of the part at the feeder exit is the same as that required for insertion then a minimum number of degrees of freedom are required from the robot arm. If the attitude of the part at the feeder exit is different from that required for insertion then extra degrees of freedom are required. Parts which need to be re-orientated from the horizontal to vertical position require an extra roll or pitch axis and parts which are required to be turned end-to-end need an extra yaw axis. Additionally, certain parts may require that final orientation from the feeder is accomplished using a robot with limited sensory capability to define the orientation. This is applicable to feeders which present the part in a limited number of known orientations. This knowledge can be collated to form a database from which it is possible to predict handling and dexterity requirements for the robot assembly system. Various organisations have created database software applications for this design process.</p> <p><strong>ROBOT ASSEMBLY HANDLING EXPERT SYSTEM<br> </strong><br> It must be possible to describe a part being analysed so that the most appropriate feeding device can be selected. A standard parts coding system is used to describe a part, as mentioned previously. The sequence of questions which are asked to describe the part is very important. The response to certain questions may create a need for further questions to fully describe the part. Alternatively, no further questions may be required. Additionally, a particular response to a question may dictate that only one handling device is appropriate, even before the part has been fully classified. Anybody using the 'selection of parts presentation device technique doesn’t want to be asked a lot of irrelevant questions and so a decision tree has to be developed to ask the minimum number of questions. Statements are presented in a structured format and these statements can be either true or untrue for a particular part. Branching forward only takes place when a particular statement is true, otherwise alternative questions are presented until a correct statement is chosen. Questions are structured so that if a particular set of statements are untrue then the previous true response to a statement must have been incorrect and that statement is once again presented to the user. By this method, the minimum number of questions are needed to classify a part in terms of its handling suitability.<br> <strong><br> PRODUCT AND SYSTEM DESIGN FOR ROBOT ASSEMBLY SOFTWARE</strong></p> <p>The presentation of parts for robot assembly is one section of a product and system design for robot assembly computer software application. It operates on eight screen pages. The first screen page allows the user to enter part numbers and descriptions to the application. The last three screen pages contain economic information and they provide the user with calculated information. The middle four screen pages are all concerned with defining the handling, and to some extent the insertion, requirements of the part under consideration. These four screen pages are displayed consecutively for each part and, when all the parts have been defined, the remaining three screen pages are displayed. In the handling section, the first screen page deals with adverse physical properties of the part. The second screen page deals with the geometrical symmetry features of the part. The third screen page deals with the geometrical asymmetry features of the part. The fourth screen page is used to define the insertion direction of the part and to determine if the part is potentially redundant. </p> <p> <small> <a href="http://russell-davison.blog.co.uk/2006/06/24/robot_parts_3~907166/#comments">Comments</a> </small> </p>tag:russell-davison.blog.co.uk,2006-06-23:/2006/06/23/robot_parts~904417/russell-davison2006-06-23T09:46:27+02:002006-06-23T09:49:13+02:00 <p><strong>DATA ACQUISITION FOR ROBOT ASSEMBLY SEMINAR</strong></p> <p>A series of product design for robot assembly seminars were held at a UK university. They were well attended and the object of these seminars was to encourage industrialists to analyse their products, using a product design for robot assembly computer software application. The results of these studies were then investigated by university staff so that handling, gripping and insertion requirements for robot assembly could be recommended. These seminars were funded by the ACME directorate as a means of forging closer links between universities and industry. The results of the studies also gave direction to future research work at the university in the field of robot assembly. Interested parties were given a copy of a computer software application. Industrial product data was stored in standard ASCII files and this was easily manipulated by staff at the university. Statistics were produced that indicated trends in parts geometry and the physical properties of parts. These statistics showed the relative importance of various pieces of assembly automation for a cross-section of industrial products and they gave indicators for future assembly hardware development.<br> <strong><br> FUTURE WORK</strong></p> <p>I strongly believe that industry will only demand products and services if there is a genuine need for either. For this reason, my direction is heavily influenced by the continuously changing needs of my clients. Product information (available to clients) and calculated information (demanded by clients) is monitored through my consultancy contracts. My approach to the presentation of parts for robot assembly is changed to best suit the needs of the majority of my current clients and future clients. The results of the previously mentioned data acquisition seminars influenced the range of handling devices included in the database. It was necessary to include other devices to cater for particular categories of parts, that were thought to exist in smaller numbers than in reality. The findings also affected the handling expert system format. The sequence of questions was altered so that the minimum amount of information was required for the majority of parts. Later, a consortium of six companies was being formed to interface the product design for robot assembly software with a conventional CAD system. The object of this work was to allow a product designer, using a CAD system, to have the benefit of product design for assembly running in the background, which only became active when adverse robotic assembly properties were evident.</p> <p><strong>CONCLUSIONS</strong></p> <p>The presentation of parts is a topic often neglected by those considering robot assembly and yet it accounts for the majority of the cost for an installation. It is important to be able to describe the features of a part by the use of a parts classification technique that is sufficiently comprehensive to fully describe the part, without involving undue effort, or understanding, from the user. Parts presentation devices for robot assembly should have a high general-purpose content and a low special-purpose content. The orientation of the part during insertion affects the choice of handling device and the number of robot degrees of freedom. The classification of a part for handling can be a tedious process and it is important to only define features that are relevant for the selection of handling devices. This is best achieved by using an expert system approach and decision trees. The complex process of handling device selection can be carried out by computer software applications, thus eliminating the need to manually carry out many iterative calculations. The types of handling devices which best suit the needs of industry can be chosen by asking current and potential industrial users to specify their particular handling requirements. Most of the information relating to the design features of products, for robot assembly, can be extracted from a CAD system database. </p> <p> <small> <a href="http://russell-davison.blog.co.uk/2006/06/23/robot_parts~904417/#comments">Comments</a> </small> </p>tag:russell-davison.blog.co.uk,2006-06-22:/2006/06/22/robot_assembly_1~901551/russell-davison2006-06-22T08:38:41+02:002006-07-27T08:12:08+02:00 <p>I originally presented this article, "Design for Robot Assembly", as a guest speaker at the UK's 2nd National Conference on Production Research ...</p> <p><strong>SUMMARY</strong></p> <p>The design of products and systems for robot assembly requires a new approach to that used for manual and automatic assembly. Robot assembly is only effective if the robot’s flexibility is used to best advantage. Additionally, peripheral devices supporting the robot must also be adaptable to handle a wide variety of products and product parts. This is achieved by using equipment that is not designed specifically to handle a particular type of part with minor modifications to tooling, or the use of a different software application, the robot assembly system can be quickly adapted to assemble a different product or product style. By this method, robot assembly can be economically justifiable in many situations where it would otherwise have been precluded.</p> <p>This article discusses the development of robot assembly systems and describes how product design plays an important role in the design of the equipment.</p> <p><strong>INTRODUCTION</strong></p> <p>There are three categories of system used in product assembly. These are manual assembly, automatic assembly and robot assembly. Whilst assembly can be classified in this manner, it is not uncommon to find an assembly system consisting of two or all of these groups to form a hybrid system. Manual assembly systems account for the majority of applications. Automatic systems are used in situations where the demand is high and there is no, or limited, change in the product styles being assembled. Robots have yet to make a significant impact in the field of assembly. It’s difficult to technically justify the use of assembly robots as the operation time of programmable devices is longer than that of dedicated automatic equipment. The economic justification of assembly by robots is equally difficult due to the characteristically small batch sizes for which these systems are appropriate. This has the effect of increasing the handling and insertion costs of the product being assembled.</p> <p>Manual assembly is still used for more than ninety per cent of all assembly tasks. This is because many products are required in low volumes and with a high degree of variety. Robot assembly could account for more than fifty per cent of all assembly tasks if it could be made to be economic for much smaller annual production volumes. This could be achieved by assembling more than one family of products on one system. For this approach to be effective, two major conditions must be met. The proportion of re-usable, or general-purpose, equipment must be high and the time taken to re-configure the system for the assembly of the next product must be low.</p> <p><img src="http://i7.tinypic.com/212fmee.jpg" alt="Russell Davison" title="Russell Davison"><br> Using existing technology, the industrial applications where robots can readily be used have been filled. These applications include paint spraying, spot welding and materials handling. Only a very small proportion of existing robots are used for assembly.</p> <p>Robot assembly system equipment is either general-purpose or special-purpose. A robot assembly system should have a high proportion of general-purpose equipment and a low proportion of special-purpose equipment. The cost of a system, with a high proportion of general-purpose equipment, can be amortised by all the products that are being assembled by the robot. This is important when trying to economically justify the use of robot assembly for products required in low volumes. Under these conditions, many products or product styles, each with a low annual volume, can be grouped together and assembled on a single robot assembly station to obtain a high system utilisation. </p> <p> <small> <a href="http://russell-davison.blog.co.uk/2006/06/22/robot_assembly_1~901551/#comments">Comments</a> </small> </p>tag:russell-davison.blog.co.uk,2006-06-21:/2006/06/21/robot_assembly_2~899583/russell-davison2006-06-21T14:44:11+02:002006-06-21T14:44:11+02:00 <p><strong>THE HANDLING OF PARTS FOR ROBOT ASSEMBLY</strong></p> <p>Handling device selection for a particular part depends on the size and geometry of a part, as well as the rate at which the part is required. Each handling device has its own performance characteristics. This means that it is suitable for dealing with a limited range of parts. Small to medium sized parts, with features that can be seen in silhouette, can be handled by the most common of devices, the vibratory bowl feeder. Parts with no useful features for orientation purposes, or parts with adverse physical properties, are expensive to feed automatically and require special automatic feeding devices. These types of parts need to be re-designed to reduce their cost for automatic feeding. There are many properties of a part that would prevent it from being handled by vibratory bowl feeders, such as flexibility and stickiness. Parts with adverse properties such as these, and larger parts, must be handled by other feeding devices like magazine systems or pallet transfer systems.</p> <p>The multi-part linear vibratory linear feeder can deliver different parts to a robot assembly station. It consists of two straight and parallel vibratory orientating tracks on a common drive unit. The rejected parts fall into return tracks and are brought to the start of the orientating tracks by a reciprocating elevator. The tracks can be CNC machined from a database of designs that are identified by an automated handling code for a particular part. Only the orientating tracks are replaced to changeover this multi-part feeder to handle other part types. The vibratory drive unit and reciprocating elevator are completely re-usable and the cost of these devices is divided between the different part types. The orientating track for this multi-part feeder is straight and it is much less expensive to produce than the curved orientating track of a vibratory bowl feeder. Applications of this feeder are limited to parts which require orientating devices simple enough to be produced in one set-up on a horizontal machining centre.</p> <p>Gravity feed track magazines are simply short lengths of track which are loaded manually on-line or off-line. During off-line loading, a full magazine is substituted for a magazine when it becomes empty. These magazines are specifically designed for the particular type of part type and cannot easily be re-used for different types of parts. Although most of the gravity feed track magazine is special-purpose, the cost of these devices is relatively low. They are useful far feeding large parts and they provide an economic alternative to palletisation. Parts that are to be handled by this type of device must be stackable, for vertical magazines, and not susceptible to damage when the part is slid into position by the pusher.</p> <p>The pallet transfer system consists of a walking beam transfer device to load a paternoster, an unload paternoster, and pallets. Full pallets are elevated by the load paternoster and transferred to the robot working zone by the walking beam transfer device. Parts are picked from the pallet and the pallets are then indexed to present a new pallet of parts to the robot. Empty pallets are offloaded from the walking beam by an unload paternoster that produces a stack of empty pallets. Virtually all of the pallet transfer system is general-purpose, with only the vacuum-formed part retainers being specific to a particular component. Pallets are loaded by standard means. Filling of the pallets at the point of manufacture is a very economic way of loading parts, although the cycle time of most manufacturing operations makes it difficult to use this method of loading. Parts are positively held in position on the pallet by ensuring that they are sandwiched between the underside of one pallet and the top of the one beneath. </p> <p> <small> <a href="http://russell-davison.blog.co.uk/2006/06/21/robot_assembly_2~899583/#comments">Comments</a> </small> </p>tag:russell-davison.blog.co.uk,2006-06-20:/2006/06/20/robot_assembly_3~895985/russell-davison2006-06-20T09:21:46+02:002006-07-27T08:19:17+02:00 <p><strong>THE ORIENTATION OF PARTS FOR ROBOT ASSEMBLY</strong></p> <p><img src="http://i7.tinypic.com/212fz9u.jpg" alt="Russell Davison" title="Russell Davison"><br> An assembly robot will never have the dexterity or intelligence of its human counterpart. A manual worker is able to pick a part, in random orientation, from a storage bin and orientate it - ready for insertion. The human senses of sight and touch are used for this purpose. Whilst a manual worker can perform these tasks with comparative ease, a robot requires a large amount of computer processing power and many feedback devices to achieve any form of intelligence and, even then, the cycle time of the operation is so long as to make it uneconomic to use robots for bin picking. Automatic feeders for robot assembly must, therefore, present parts to the workhead in a known orientation, or in a limited number of known orientations. The attitude of the part on the feed track or pallet influences the number of robot degrees of freedom required. More degrees of freedom are required for those parts which are inserted in a different attitude to which they are presented. In the case of parts which cannot be presented in one known orientation, the final orientation must be carried out by a robot with extended capabilities. This involves sensing and part manipulation, to achieve the required insertion orientation.</p> <p><img src="http://i7.tinypic.com/212g2lh.jpg" alt="Russell Davison" title="Russell Davison"><br> The robot work envelope poses limitations on the automatic feeder types that can be used in robot assembly. Each part is presented to the workhhead at the end of a track or on a pallet. The space occupied by the material of these devices must also be considered when determining the maximum number of parts that can be fed to any one robot. Robots that<br> can only access parts in the vertical axis must have parts arranged so that they can all be seen in plan view at the part presentation points. Another problem arises when turret mounted grippers are used. The grippers can occupy a large volume in space and this makes the avoidance of collision very important. This situation can be investigated before the design of the robot assembly system is finalised. The complete assembly process can be studied using computer simulation and there are many three-dimensional graphic simulation packages available that can identify if a collision is likely to occur.</p> <p><strong>THE INSERTION OF PARTS FOR ROBOT ASSEMBLY</strong></p> <p>An insertion operation is defined as being the action whereby a part is added to a work fixture, another part, or part-built assembly. This may involve a simple vertical downwards motion where the part is added to the part-built assembly, without being immediately secured. Alternatively, it may be a complex motion, such as that required for the application of an<br> adhesive to a part. Each insertion process may require a different type of end effector and each process takes a certain amount of time to be executed. It’s possible to categorise each type of insertion process to define the type of end effector required and to estimate the time it would take to carry out the operation.</p> <p>The end effectors may be accessed by the robot arm in many ways. The design of end effector, and the method of mounting it onto the arm, influences both the cycle time of the process and the cost associated with the insertion of a particular part. The simplest, yet most expensive and time consuming, method of accessing an end effector, is to use an individual gripper, or tool, for each part or insertion process. The grippers and screwdrivers are stored in a rack within the work envelope of the robot arm. The relevant tool is picked from the rack, used for the insertion process, and then returned. The action of picking up the tool, and returning it, can often take longer than the insertion process itself. </p> <p>Another method of inserting many different designs of parts is to use a multi-functional gripper. Only one gripper with a multitude of faces is used, for the internal or external gripping of parts. The time involved with gripper changing is eliminated, but the design of the gripper is complex and other tools cannot be mounted onto the same unit. Problems may also occur because only one set of jaws is being used for the insertion of many parts. The gripper designer has to ensure that the gripping force is sufficient to hold the part and yet not too excessive as to cause damage to the part. The varying force requirements can be met by additional gripper sensing. This, of course, increases the cost of this design of end effector.</p> <p>The most efficient method of accessing a multitude of end effectors is to mount them onto an indexing turret. Between eight and twelve tools can be housed on one unit, depending on their size. Grippers, screwdrivers and other tools are mounted in a circle. This may be about a vertical, horizontal or inclined axis. The use of universal mounting plates, between the turret and the end effectors, allows interchange-ability of grippers and tools for product changeover. The time lost, due to gripper changing, is minimised because indexing of the turret occurs between movements to, and from, the parts feeders.</p> <p>Most products, or sub-assemblies, have many possible sequences of assembly and it is important to recognise the most appropriate sequence, particularly in robot assembly. In all forms of line assembly, where moving work carriers are employed, it is good practice to secure parts as soon as possible because subsequent work carrier movements may cause a<br> part to be displaced. This suggests certain precedences. If no movement of the part-built product occurs during assembly then the securing of parts is not important and a sequence of assembly can be chosen which involves a minimum number of gripper changes.</p> <p>Consideration also has to be given to the appropriate action needed when a malfunction occurs. The decision to scrap, rectify or dismantle depends on the; value of the part-built assembly, frequency of the malfunction, labour cost and sequence of assembly. In single station robot assembly, an overriding consideration is the cost of gripper changing. The optimal sequencing, linked with appropriate product design, can significantly reduce this cost. Computer software applications are available which, given the precedence constraints, identify the optimal sequence to minimise gripper changes. The cost of error recovery is important. The alternative actions need to be examined at each stage in the assembly build and the cost of these actions should be determined for all possible sequences. This activity is influenced by the chosen criteria of; minimum cost, maximum production or maximum profit.</p> <p> <small> <a href="http://russell-davison.blog.co.uk/2006/06/20/robot_assembly_3~895985/#comments">Comments</a> </small> </p>tag:russell-davison.blog.co.uk,2006-06-19:/2006/06/19/robot_assembly_4~892930/russell-davison2006-06-19T08:45:24+02:002006-07-27T08:20:33+02:00 <p><strong>PRODUCT DESIGN FOR ROBOT ASSEMBLY</strong></p> <p><img src="http://i7.tinypic.com/212fzwl.jpg" alt="Russell Davison" title="Russell Davison"><br> Three factors determine how easy it is to use an assembly robot for a product. Each product part should be examined with respect to these three important qualities. In order of priority, they are the; necessity of the part to be separate from those which have already been assembled; ease with which the part can be handled, and the ease with which the part can be inserted. By considering these factors in turn, the most economical design of product can be chosen for robot assembly. A measure of the assemble-ability of the product is the 'design efficiency', and this is related to the above factors.</p> <p>A part is considered to be necessarily separate from those previously assembled if one of four conditions apply to the part. Otherwise, it can be eliminated. Firstly, if the part or sub-assembly moves relative to its mating part during the normal function of the final assembly then it must be a separate part. Secondly, if the part or sub-assembly must be of a different material than its mating part (eg. for insulation, vibration damping) then it must be a separate part. Thirdly, if disassembly of the part or sub-assembly must be allowed for (e.g. servicing requirements, recycling) then it must be a separate part. Finally, if the part or sub-assembly, when combined with it’s mating part, would prevent the assembly of other separate parts (except where the part's only function is to fasten) then it must be a separate part.</p> <p>The majority of insertion processes take place along, or about, the vertical axis. If the action of insertion for a part is not in the vertical axis then the process should be analysed to see if the more complex insertion path is really necessary. If possible, it should be re-designed to take place in only one axis. The vertical axis is always the preferred axis because the weight the part acts in this direction and assists, not hinders, the operation. The robot cost is lower if insertion processes are kept simple. This is because complex operations need more robot degrees of freedom and each degree of freedom requires an individual pneumatic, hydraulic or DC servo motor which increases the cost of the equipment. Additionally, the potential profitability of the equipment is reduced because the cycle time of the operation will also be increased.</p> <p><strong>CONCLUSIONS</strong></p> <p>The use of assembly robots will increase in the future if the ancillary equipment, i.e. end effectors and parts feeders, are as flexible as the robot. The feeding devices should present the parts in a known orientation so that the dexterity required from the robot is low. The cycle time of the operation would be lowered and, consequently, the assembly rate increased. The flexibility of the feeders is ensured by using devices with a low special-purpose content. An indexing turret, used for gripper mounting, minimizes the time lost due to gripper changing. For any form of gripper mounting, the cycle time can be minimised by using a sequence of assembly which needs the least number of gripper changes. Operator involvement can be minimised by developing strategies which allow the robot to recover from error situations, without the assistance of manual labour. The cost of robot assembly can be minimised by designing the product for robot assembly. This involves using the minimum number of parts and ensuring that the parts can be easily handled and inserted. </p> <p> <small> <a href="http://russell-davison.blog.co.uk/2006/06/19/robot_assembly_4~892930/#comments">Comments</a> </small> </p>