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5.3.2 Utilization of tools and techniques As part of a concurrent engineering framework, four formal methods, FMEA, QFD, DFA/DFM and DOE, have been identi®ed as complementing concurrent engineering working and their application in general shortens the total product development time (Norell, 1992; Poolton and Barclay, 1996). Although methods like QFD and Taguchi's Robust Design have been stated to yield good results by users in Japan and the USA, surveys have shown that their utilization is not as high as might be expected (Araujo et al., 1996). Possible reasons for this are: . Companies unaware of their existence . Companies unaware of the quality related bene®ts that may accrue from their use . There are dierences in companies and/or their products that reduce their useful- ness under certain circumstances . Eective utilization requires experienced or trained sta who may not be available in some companies. The popularity of some of the key tools and techniques mentioned is shown in Figure 5.10, taken from two dierent surveys of UK companies. The importance of FMEA, DFM and DFA is apparent, although the survey conducted in 1994 did not ask for the usage of DFM or DFA. Equally, the 1996 survey did not include Poka Yoke. The minor popularity of techniques such as QFD, DOE and Robust % of companies using a particular technique Survey (Booker, 1994) Technique 90 80 70 60 50 40 30 20 10 0 FMEA DFM DFA QFD POKA YOKE FTA DOE ROBUST DESIGN SPC Figure 5.10 Percentage of UK companies surveyed using a particular tool or technique (Araujo et al., 1996; Booker, 1994) Tools and techniques in product development 265 Design is a re¯ection on the comments made earlier. The popularity of SPC is shown for comparison to gauge the philosophies of `o-line' and `on-line' quality. 5.3.3 The integration of tools and techniques in the product development process To achieve successful concurrent engineering design, one needs an integrated frame- work, a well-organized design team, and adequate tools and techniques (Jin et al., 1995). Some companies in various countries have had great success in improving the quality and reliability of manufactured products by applying tools and tech- niques. However, without a proper understanding of the underlying processes they will not blend together to give an eective sequence of actions (Andersson, 1994). It is possible and quite common to perform them individually, but it is their joint use that gives the greatest value, through the increased co-operation from their use in cross-functional teams (Norell and Andersson, 1996). When a single technique is employed only local life-cycle cost minimization is achieved. If the global life-cycle cost is to be minimized, a number of techniques have to be applied (Watson et al., 1996). In this case, tools and techniques shouldn't compete with each other, but be complementary in the product development process. The correct positioning of the various o-line tools and techniques in the product development process, therefore, becomes an important consideration in their eective usage. Patterns of application have been proposed by a number of workers over several years (Brown et al., 1989; Jakobsen, 1993; Norell, 1993) and the importance of concurrency has been highlighted as a critical factor in their use (Poolton and Barclay, 1996). Before setting about the task of developing such a model, the product development process requires de®nition along with an indication of its key stages, this is so the appropriate tools and techniques can be applied (Booker et al., 1997). In the approach presented here in Figure 5.11, the product development phases are activities generally de®ned in the automotive industry (Clark and Fujimoto, 1991). QFD Phase 1 is used to understand and quantify the importance of customer needs and requirements, and to support the de®nition of product and process requirements. The FMEA process is used to explore any potential failure modes, their likely Occurrence, Severity and Detectability. DFA/DFM techniques are used to minimize part count, facilitate ease of assembly and project component manufacturing and assembly costs, and are primarily aimed at cost reduction. To be eective, we see the need for CA, which comes under the heading of CAPRA or CApabilty and PRobabilistic Design Analysis, to be integrated into the early stages of design too, if it is to have its full impact. This will require the designer to de®ne acceptable system performance more precisely than is presently the case. Design information from other techniques such as FMEA are crucial in this connection, as discussed in Chapter 1. CA is employed to provide a measure of potential process capability in manufacture and assembly, and to ensure robustness against failure and its associated failure costs. When used in conjunction with DFA/DFM, CA helps to assure the right part count and design of the assembly so that the required level of conformance can be achieved at the lowest cost. The integrated application 266 Effective product development of FMEA, DFA/DFM and CA has many bene®ts including common data sharing and assembly sequence declaration. The outputs of FMEA and CA in terms of critical characteristics and any potential out of tolerance problems focuses attention on those areas where DOE is needed. The process capability requirements for component characteristics determined by CA are used to support the supplier development process. In the approach, new designs of `bought-in' parts such as castings, plastic mouldings and assembly work are discussed with process capability requirements as the ®rst priority. Where a potential problem with the tolerance on a characteristic has been identi®ed, this Figure 5.11 Effective placement of tools and techniques in the product development process Tools and techniques in product development 267 will be discussed and examined with the supplier. The supplier will be encouraged to provide evidence that they can meet the capability requirements or otherwise by refer- ence to performance on similar part characteristics. The approach is supported by the application of SPC in the factory and the encouragement and facilitation of work- force involvement in a process of continuous improvement. The so-called Q7 tools and techniques, Cause and Eect Diagrams, Pareto Analysis, etc. (Bicheno, 1994; Dale and McQuater, 1998; Straker, 1995), are applic- able to any stage of the product development process. Indeed they support the working of some of the techniques mentioned, for example using a Pareto chart for prioritizing the potential risks in terms of the RPN index for a design as determined in FMEA (see Appendix III). A particular diculty in-product development is to properly and eciently tie in reliability prediction methods with the design process so as to gain maximum return on investment (Klit et al., 1993). Businesses need to develop economical and timely methods for obtaining the information needed to meet overall reliability goals at each step of the product design and development process (Meeker and Hamada, 1995). Also under the CAPRA heading is the design for reliability methodology, CAPRAstress, described in Chapter 4 of this book. Data relevant to CA is applied here also, therefore CAPRAstress should ideally be performed at the end of this phase of the product development process, as capability knowledge and knowledge of the service conditions accumulates, together with qualitative data already available from an FMEA. A proposed product development process that facilitates designing capable and reliable products has been outlined above. It must be stressed that the product development process itself will not produce quality products, and consideration of many issues are crucial to success, such as company strategy, management structure, commitment, sucient resources, communication, and most importantly pro®cient engineering practices, such as the following. 5.4 Supporting issues in effective product development Tools and techniques can enhance the success of a product, but alone they will not solve all product development issues (Jenkins et al., 1997a). Any implementation of tools and techniques within the product development process must take the following into account if the outcome is to be eective at all: . Team approach to engineering design . The company's quality philosophy . Adequate Product Design Speci®cation (PDS) . Assessment of external supplier quality . Adequate number of design solutions . Adequate design reviews . Adequate con®guration control of product design and processes issues . Adequate Research and Development (RandD) should be completed before com- mencement of the project. Several of these issues will be discussed in detail next. 268 Effective product development 5.4.1 Team approach to engineering design Even with the aid of tools and techniques, engineering is still a task that requires creative solutions (Urban and Hauser, 1993). Companies recognizing the importance of product development have searched to resolve this problem, with most opting for some kind of `team approach', involving a multitude of persons supposedly providing the necessary breadth of experience in order to obtain `production friendly products'. Research (Urban and Hauser, 1993) has shown that teams produce better engineer- ing solutions. Team sizes should be kept to three or four for best performance; however, up to nine or ten can work eectively together (BS 7000, 1997; Straker, 1995). The use of multi-functional teams also enables concurrent engineering, since all the team members are aware of the eect of their functional input to the project on other areas, as discussed earlier. The team are able to plan activities that may be carried out in parallel. While sometimes obtaining reasonable results, this approach often faces a number of obstacles (Towner, 1994): . Assembling the persons with the relevant experience . Lack of formal structure. Typically such meetings tend to be unstructured and often ad hoc attacks on various `pet' themes . The location of the persons required in the team can also present problems. Not only are designers and production engineers found in dierent functional depart- ments, but they can frequently be on dierent sites and are in the case of sub- contractors in dierent companies. In addition, the chances are that the expertise in the team will only cover the primary activities of the business and hence opportunity to exploit any bene®ts from alterna- tive processes may be lost. The ideal concurrent engineering scenario would involve a single product development team whose co-location would enable close communica- tion and mutual understanding between team members (McCord and Eppinger, 1993). An important way of encouraging multi-functional team working, however, is to use tools and techniques that provide structured ways of achieving important objectives, such as (Parker, 1997): . Understanding what the customer wants . Design products for ease of manufacture and assembly . Making sure products and processes are safe . Improving process capabilities. Furthermore, in order more eectively to create quality, the people involved must be empowered to make changes in the products and processes they are involved with (Kolarik, 1995). 5.4.2 Quality philosophy of the company It is quite possible for a company to be registered under BS EN ISO 9000 or QS 9000 and still be producing products which are defective and not to customer requirements. Supporting issues in effective product development 269 Product quality may not necessarily be better than that in a non-registered company. To some, especially small companies, registration is an unnecessary bureaucracy. However, to many it is a way of demonstrating, internationally, that the company takes quality seriously and has thought through its quality system. BS EN ISO 9000 registration is seen as a marketing advantage and a trade facilitator (Bicheno, 1994). However, it does reveal bottlenecks in the organization and in the handling of projects. The general opinion throughout companies surveyed is that once you are registered, as far as quality is concerned it made little or no dierence. In fact, recent articles on the quality standards will, in general, reveal an anti-trend. More speci®cally, the main criticisms are (McLachlan, 1996): . It is too expensive . It does not address the needs of small businesses . It is unduly biased towards manufacturing . Is it relevant? . You can still make and sell rubbish. Traditionalists say that you cannot write a standard to achieve quality. Quality depends on people doing their job properly having made sure that they know what their job is, that it has been correctly de®ned and that allowance has been made for continuous improvement as de®ned by TQM. In view of the above, BS EN ISO 9000 registration and TQM complement each other (McLachlan, 1996) and the quality movement has become a driver for change in product development (Rosenau and Moran, 1993). Creating an environment which complements successful product development also involves changing the culture of the organization and the core beliefs of the people who form it (Parnaby, 1995). BS EN ISO 9000 registration and TQM support this process. TQM aects three areas of the product development process (Rosenau and Moran, 1993): . Strategic ± external and internal management of processes . Cultural ± empowerment and teamwork . Technical ± thought of as a toolbox, techniques used to facilitate TQM and the product development process. TQM involves all the organizations, all the functions, the external suppliers, the external customers and involves the quality policy. Similarly, TQM cannot be achieved without good Quality Management Systems (QMS) which bring together all functions relevant to the product, providing policies, procedures and documenta- tion. The elements of a quality organization consist of these three mutually dependent items (Field and Swift, 1996): . The culture ± TQM . Registration (BS EN ISO 9000) . Quality Management Systems (QMS). The importance of TQM is now recognized nationally with the issue of two British Standards (BS 7850, 1992; BS 7850, 1994). However, while the advantages of TQM seem obvious, implementing TQM systems has not produced equally good results 270 Effective product development in all cases. Several researchers report that TQM programmes have produced improvements in quality, productivity and competitiveness in only 20 to 30% of the companies that have implemented such initiatives (Benson, 1993; Schonberger, 1992). 5.4.3 Product design speci®cations The PDS or design brief should be a de®nitive statement or instruction of what is required. It should de®ne all the requirements and constraints, for example standards and regulations that the designer has to observe, but should not impose design solutions. It should receive contributions from many sources and should evolve through a series of iterations (BS 7000, 1997). The PDS produced from the initial market analysis is the basic reference for the new product. The PDS is important since it encourages quality in up-front stages of new product design, and reference to the PDS, throughout the product development process, ensuring that a ®nal product is developed which will satisfy the customers' needs (Jenkins et al., 1997a). PDS is one of the key factors in successful quality engineering, since it clari®es the design objectives. Important items in its construction are shown in Figure 5.12 (Andersson, 1994). 5.4.4 External supplier quality A key success factor for reducing the costs and lead times for vehicle manufacturers, for example, is the degree of integration of the suppliers within the product develop- ment process. This is seen as a natural extension to concurrent engineering principles (Wyatt et al., 1998). For many years, in engineering companies, a substantial pro- portion of the ®nished product, typically two thirds, consists of components or subassemblies produced by suppliers (Noori and Radford, 1995). An eective programme for product quality must, therefore, include a means of assuring supplier quality and reliability (Nelson, 1996). This means that the customer must get much closer to the supplier's operations. Many companies have failed to develop a supplier strategy and traditionally have used an almost gladiatorial and hostile approach to their suppliers, for example to drive them to impossibly low prices regardless of quality, or to terminate trading with those who fail to perform. Most buyers are only interested in price and delivery and not the quality of the supplier's goods and services. The more enlightened companies have now established a procurement strategy that controls the quality of a supplier, but does not take from a supplier the responsibility for their quality. The company collaborates with the supplier through the project ensuring standards are maintained. To eectively manage suppliers, a number of guidelines are proposed: . Choose suppliers who produce the required quality, not who oer the lowest price . Reduce the number of suppliers . Build up close working relationships Supporting issues in effective product development 271 Figure 5.12 Percentage of the companies applying a particular element in the PDS (adapted from Andersson, 1994) 272 Effective product development . Collaboration and mutual trust . Operational integration at all stages of design and production process. This approach has demonstrated a marked reduction in supplier prices, improved quality and delivery, and external customer satisfaction. The supplier must be regarded as part of the team and their full commitment to the project will ensure minimum inspection on receipt and the implementation of joint improvement pro- grammes. For example, the car manufacturer Nissan has been involved in a process to improve supplier quality and productivity. During a two year period they claim that 47% of their suppliers were producing 10 ppm or less, failing speci®cation (Green®eld, 1996). More on the bene®ts of the approach are discussed by Galt and Dale (1990) and Lloyd (1994). A company will typically categorize its suppliers according to their type of opera- tion, for example: . Fully design, develop and manufacture their own products . Manufacture major components from supplier designs . Manufacture simple components from third party designs. In every case the company may demand the supplier be registered to BS EN ISO 9000 or conform to their company requirements for the adequacy of their quality systems. However, as previously stated these registrations do not control the quality of the product itself. Any new suppliers must show evidence of their capability with other contracts before being awarded any orders. Any current supplier who fails to meet the standards may be removed from the bidding list. The quality assurance model represents quality system requirements for the purpose of a supplier demonstrating its capability (BS EN ISO 9001, 1994). Evaluating supplier capability at the produc- tion level involves two parts (Gryna, 1988): . Qualifying the supplier's design through evaluation of product samples . Qualifying the supplier's capability to meet quality requirements on production lots. The results from CA, described in Chapter 2, serve as a good basis for supplier dialogue very early in the development process. Problem areas in the design are systematically identi®ed and discussed openly with suppliers. The necessary process or design changes are then eectively communicated in order to meet the customer's requirements leading to a process capable design. In summary, an eective supplier development process should contain the follow- ing elements (Gryna, 1988): . De®ne a product and programme quality requirements . Evaluate alternative suppliers . Select suppliers . Conduct joint quality planning . Co-operate with the supplier during contact . Obtain proof of conformance . Certify quali®ed supplier . Conduct quality improvement programmes as required . Create and utilize supplier quality ratings. Supporting issues in effective product development 273 5.4.5 Design scheme generation Designing for quality methods have the objective of selecting the `technically perfect one' from a number of alternative solutions that have been arrived at systematically and not the ®rst satisfactory solution (Braunsperger, 1996). Developing more than one design scheme is therefore a key issue, the highest percentages of companies generating on average two design schemes at system level and three or greater sub- system schemes, as shown in Figure 5.13. In general, the more schemes generated, the more likely that an eective design solution can be isolated through the determined performance measures. The process of evaluating and comparing the design alternatives is an important mode of applica- tion of tools and techniques and replaces the aspect of exactitude which designers sometimes seek through their use. 5.4.6 Design reviews Design reviews are a formal procedure to establish the total understanding and acceptance of a design task. The purpose of reviews is to (Parker, 1997): . Monitor progress . Review quality . Identify issues . Ensure level of support . Grant permission to proceed early in the process. A design review must not consider cost and time scales; it forms a traceable record of technical decisions and current performance against requirements. Design reviews are a crucial part of product development and are an important factor in enhancing product performance (Dieter, 1986). They should also take place at the critical stages of the product development process (as highlighted in the industrial models of PIM and DMP). The participants at the design review generally include representatives 0 5 10 15 20 25 30 35 40 11to222to3>3 % of companies surveyed that generate a number of design schemes Number of design schemes System level Subsystem level Figure 5.13 Number of design schemes generated at system and subsystem level (Andersson, 1994) 274 Effective product development [...]... order gives: 407, 4 15, 420 , 424 , 426 , 428 , 433, 433, 436, 438, 440, 4 42, 443, 444, 4 45, 447, 447, 449, 450 , 450 , 451 , 4 52 , 4 52 , 453 , 453 , 454 , 455 , 456 , 459 , 460, 4 62, 466, 466, 469, 470, 471, 4 72, 474, 477, 478, 480, 4 82, 483, 4 85, 490, 4 95, 496, 498, 5 02, 51 5 From equation 6, we can determine the optimum number of class intervals to be: k 1 3 :22 log10
N 1 3 :22 log10 50 % 6 The class width... at ÿ3 from the mean for the metal and the proportion of individuals that could be expected to have a strength greater than 50 0 MPa 4 82, 470, 469, 490, 471, 4 42, 480, 4 72, 453 , 450 , 4 15, 433, 420 , 459 , 424 , 444, 455 , 4 62, 4 95, 426 , 5 02, 447, 438, 436, 498, 474, 51 5, 483, 454 , 453 , 447, 4 85, 456 , 443, 449, 466, 4 45, 4 52 , 478, 407, 433, 466, 428 , 4 52 , 440, 450 , 460, 451 , 496, 477 Solution Sorting the... 3 :22 log10
N 1 3 :22 log10 50 % 6 The class width is given by equation 9 as: w max ÿ min 51 5 ÿ 407 18 k 6 The class limits become: minimum 407 4 15 18 4 25 4 25 18 443 443 18 461 461 18 479 479 18 497 maximum 51 5 28 3 28 4 Appendix I Table 1 Area under the cumulative Standard Normal Distribution (SND) ... bene®ts, in particular giving a reduction in the number of design changes and a reduction in the time it takes to bring the product to market Tools and techniques cannot be employed in isolation and the integration of several tools and techniques has been found to eectively support the process of designing capable and reliable products For example, an important aspect of the use of CA 27 6 Effective...Summary 27 5 Figure 5. 14 Techniques for redesigning products and processes (Huang, 1996) of all functions aecting quality as appropriate to the phase being reviewed (Dale and Oakland, 1994) Following the completion of a design review, it is usual for a ®nal report to be submitted to the responsible party to summarize the recommendations made and any modi®cations subsequently... expected frequency for the Normal distribution is given by: Nw
x ÿ 2 y p exp ÿ
15 2 2 2 28 1 28 2 Appendix I Figure 4 Properties of the Normal distribution where: y expected frequency Nw scaling factor (population, N, multiplied by the class width, w): If we plot a Normal distribution for an arbitrary mean and standard deviation, as shown in Figure 4, it can be shown that at Æ1 about... approximately 68 .27 % of the total, and at 2 , the area is 95. 45% of the total under the curve, and so on This property of the Normal distribution then becomes useful in estimating the proportion of individuals within prescribed limits The Standard Normal distribution The Normal distribution can be ®tted to a set of data by `standardizing' (i.e adjusting the mean to zero and rescaling the standard deviation... appropriate tools and techniques, and with the correct mindset, can create capable and reliable designs of high value to the company and customer Manufacturing businesses must strive to reduce the costs of failure using such approaches Appendix I Introductory statistics Statistical representation of data The random nature of most physical properties, such as dimensions, strength and loads, is well... not simply to replace, but to ®nd a new and better way of achieving the same function (Dieter, 1986) The elementary processes of redesign are shown in Figure 5. 14 5. 5 Summary This chapter has overviewed various product development models found in the literature and several of those employed by industry When designing a new product, it is essential to facilitate and drive the operation by an adequate... mid-range and fewer further out to either side Statisticians use the mean to identify the location of a set of data on the scale of measurement and the variance (or standard deviation) to measure the dispersion about the mean In a variable `x', " the symbols used to represent the mean are and x for a population and sample respectively The symbol for variance is V The symbols for standard deviation are and . gives: 407, 4 15, 420 , 424 , 426 , 428 , 433, 433, 436, 438, 440, 4 42, 443, 444, 4 45, 447, 447, 449, 450 , 450 , 451 , 4 52 , 4 52 , 453 , 453 , 454 , 455 , 456 , 459 , 460, 4 62, 466, 466, 469, 470, 471, 4 72, 474,. 424 , 444, 455 , 4 62, 4 95, 426 , 5 02, 447, 438, 436, 498, 474, 51 5, 483, 454 , 453 , 447, 4 85, 456 , 443, 449, 466, 4 45, 4 52 , 478, 407, 433, 466, 428 , 4 52 , 440, 450 , 460, 451 , 496, 477. Solution Sorting. and the proportion of individuals that could be expected to have a strength greater than 50 0 MPa. 4 82, 470, 469, 490, 471, 4 42, 480, 4 72, 453 , 450 , 4 15, 433, 420 , 459 , 424 , 444, 455 , 4 62, 4 95,
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