INTERNATIONAL CONFERENCE ON ENGINEERING DESIGN ICED 01 GLASGOW, AUGUST 21-23, 2001 INNOVATION IN THE TENSION OF CHANGE AND REUSE

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1 INTERNATIONAL CONFERENCE ON ENGINEERING DESIGN ICED 01 GLASGOW, AUGUST 21-23, 2001 INNOVATION IN THE TENSION OF CHANGE AND REUSE Manuel Gerst, Claudia Eckert, John Clarkson and Prof Udo Lindemann Keywords: Drivers of innovation, Psychology of creativity, Innovation methods 1 Introduction Most new products in engineering are designed by modification from existing products for sound economical reasons. Yet most discussions of innovation in the literature take a totally fresh look at the design problem. This paper investigates the vital role of core-requirements in identifying suitable areas of innovation and analyses how innovation can be integrated with design by modification. It proposes a combination in a two stage approach where techniques are used to identify a set of starting-requirements and to map out the solution space. An analysis of the possible changes to the existing product and their impact is used to reduce the number of possible solutions and to carry out a trade-off between fulfilling requirements and the impact the changes will have on the product. 2 Innovation All companies must innovate to maintain competitive advantage. In practise the majority of all new products are designed by modification from existing products, reusing product properties, functionality, solution principles, parts and components. This paper addresses the fundamental question that all companies must address: How can we know what can be changed and what should be reused? 2.1 Traditional views on innovation Common models of innovation processes distinguish between technology push, where new technical developments allow the generation of a new product for which a market needs to found, and market pull, where companies tend to understand innovation as a new or reinforced market-oriented way of thinking. Methods like Quality Function Deployment (QFD) or Target Costing support this way of thinking, by translating customer requirements into technical product characteristics with appropriate parameter values and associated allowable costs. Innovation is driven by the aim to increase customer satisfactions by meeting requirements better and to maximise profit through meeting customer requirements in a more economical way. These methods largely leave the considerations of technical realisation aside. They create a possibility for technical innovation while making the risk hard to estimate. Established creativity methods, such as brain storming or method [1] are aimed at the development of new product ideas. These methods aim explicitly to free the designer from the bias of past designs. They enable designers to generate many new ideas, which later need to be carefully evaluated. In this situation, designers are rarely short of ideas, but many of them

2 are not appropriate for realisation later in the design process. A successful idea is one that leads to a working prototype and ultimately a production model which performs well in the market place. In industry development rarely aims at totally new products, more often focusing on the improvement of existing products to meet new customer requirements. Rather then designing a new product, designers mostly modify some components or subsystems of an existing product while leaving others intact. 2.2 Stable balance between requirements and product properties A product that has been successfully introduced into the market can be seen as a stabile balance between its properties and its requirements. If new core-requirements for the system arise, all requirements have to be redefined, which in turn leads to changes to the product and the system is thrown out of balance (see Figure 1). In complex products designers rarely understand all the implications of a change to the product: Propagation of changes to product. A change to one part of the product can affect many other parts. The cumulative effect of several changes is especially hard to predict [2], and hence the likely costs of change are in turn hard to predict. In the extreme, change may give rise to further money- and time-consuming changes, or a decrease in the quality of the product [3]. Effects on buyers behaviour. The market can find radical changes (innovation) difficult and might show an ambivalent reaction. A previously used concept has a higher credibility for the consumers, because they feel that the idea is proven. This view is justifiable as new innovations are often brought to the market without being fully tested and customers are inconvenienced when they fail, are recalled or changed. Amount of Innovation Changes to the system? Technical System A2 B2 Changes to requirements? New stable balance Productplanning A1 B1 C1 D1 t Figure 1. Stable balance of states Innovation is found in the constant tension between change and reuse. Why should something that works be changed? One reason could be in reaction to another change. Designers must be aware of the implication of a possible change or a possible reuse. The reuse of existing solutions, components, manufacturing techniques and equipment makes sound economical

3 sense. It reduces design time, saves on development and testing costs, enables companies to reuse specific tooling and allows bulk ordering. Change might be necessary to maintain a competitive edge, not just for this product, but as part of an innovation strategy. 2.3 Our study This paper reports on ongoing collaborative work between Institute of Product Development at the Technische Universität München (TUM) and the Engineering Design Centre (EDC) at the University of Cambridge. Both groups have longstanding experience in innovation research [4, 5] and are researching change and customisation processes [2, 3, 6]. This paper draws in particular on process modelling and the findings of 20 interviews with engineers and engineering managers in an automotive company. 3 Innovation as a response to changed requirements Product innovation is driven by core-requirements that define the desired behaviour of the new product. In our case study the automotive company had developed 6 core-requirements for a new car through market research and internal discussion specifying for example the new car should be more sportive and have better handling. This wish list was broken down into technical core-requirements such increased acceleration by x %. Conventional design methods stress the importance of a full requirement analysis, but without having clearly specified core-requirements the designers are in danger of loosing sight of their goal and can t prioritise their requirement [7]. Borrowing the term from marketing, we define product strategy as the core-requirements and important technical and commercial requirements. In response to the product strategy designers can develop an innovation strategy, which identifies those product innovations that are desirable; and can re-evaluate other requirements in the light of the innovation strategy. 3.1 Identification of a set of starting-requirements A design process must begin with establishing a product strategy and is driven by it. Most fundamentally core-requirements aim to increase customer benefit by offering a more attractive product or to increase profits, for example by decreasing manufacturing costs or building up a new skill base in the company. Core-requirements are those that give a company an edge over its competitors and their fulfilment is vital to the company. Cost savings are core-requirements in most development projects, however cost increases can be justified by customer needs. Other core-requirements can be derived from the main reasons why a customer would buy the product (Purchase Promotion Factors). Further requirements can arise from the needs of a particular organisation, such as adequate use of internal resources. Core-customer requirements can be found through market or customer analysis as well as internal discussions. Customers rarely know the technical requirements that would encourage them to buy the product and don t understand long-term market and technological trends. Some companies use a Product inventory to look at the range and history of their products, identifying good and bad points, in order to find the factors that define the brand identity. Then can then use this information to evolve the brand in an appropriate way.

4 The product strategy includes not only those decisive requirements that make the customer buy a particular product, but also basic-requirements for the successful and safe use of the product. It also includes constraints on the core-requirements, such as limitations on the applied solution principles that stop the designers from scaling up existing designs without major changes to the fundamental design of the product. The distinction between core-requirements, basic-requirements and constraints are important in the development of an innovation strategy for a particular product and across the entire company (see Section 4). Typical requirements lists distinguish between compulsory must have requirements and optional nice to have requirements. However, it is often the optional requirements that form the starting point for the product strategy. From a customer s point of view the flip side of the purchase promotion factors are the purchase rejection factors. These stop the customer from buying a product. Hence such factors can be used to define the basic-requirements for the product. Without knowledge of the rejection factors, the product may not sell. However, they do not give the product a competitive advantage. Industrialists tell us that it is often easier to find out what customers do not want, than to find out what they really want and what makes them excited about the product. Further restrictions leading to basic-requirements can originate from the company itself, competitors or suppliers. They may arise because of technical, economical, legal, social or ecological reasons. Frequent sources of restrictions are companies or suppliers design or production processes, for example time pressure, cost pressure or standardisation as well as competitors patents. 3.2 Classification of requirements To identify a set of starting-requirements designers need to be able to prioritise requirements. This can be achieved, for example, through use of the following classification of requirements. Kano [8] differentiates between excitement-requirements, performancerequirements and basic-requirements, each reflecting different levels of customer satisfaction. Excitement-requirements lead to high customer satisfaction, since they are not expected and satisfied even when they are not completely met. Basic-requirements do not lead to high customer satisfaction as they are strongly expected (even though not explicitly) and their absence causes dissatisfaction. Performance-requirements range between excitement and basic-requirements and can best be expressed by the customer, reflecting the customers expectation of the product. To prioritise requirements we classify them by the way they affect solution generation (see Figure 2). In an extension to the Kano model, requirements can be classified as: vital requirements including excitement-requirements, which capture those features likely to gain unexpected customer satisfaction, identity-requirements, which maintain the identity of the brand, and core-requirements; important requirements are the Kano performance-requirements, which are expected by the customer; boundary requirements are basic-requirements and constraints, which need to be fulfilled to have a viable product.

5 Purchase Promotion Factors Vital requirements New features Identity requirements Important requirements Purchase Rejection Factors Boundary requirements Basic requirements Constraints Figure 2. Classification of requirements (according to Kano-Model) As time passes requirements are increasingly taken for granted by the customers. For example, at first safety belts were excitement-requirements, then they become performancerequirements for all good cars and now they are basic-requirements, without which nobody would buy a car. Performance-requirements that have been maintained and updated over many years in company become identity-requirements. 4 Handling the risk of innovation An important question at the beginning of most design projects is to what extent innovation becomes necessary and how it should be applied. Figure 3 describes a procedure that can help designers to build up an innovation strategy by defining parts, components or product functions whose change becomes necessary and vital for further product success. Mapping out the solution space II Solution approaches Change propagation assessment Set of starting - requirements I III Technical impacts trade off I Economical impacts Figure 3. Requirement change cycle The selection of suitable areas of innovation in a product depends on the risk they carry. The risk must be assessed with regard to the effect of an innovation on the entire solution, the chance of changes propagating through the system, the effects of the changes on the design

6 and manufacturing process and the effects on the customers purchasing behaviour. Even though risks can be taken at the level of single components or parts, the total risk of the development project must remain manageable and commensurate with the effects of a possible failure. In the following section we describe a procedure showing how, starting from a set of requirements, necessary innovations can be identified and possible solutions evaluated according to their technical and economical impact (see Figure 3). 4.1 Mapping out the solution space To work out an innovation strategy it is important to map out the solution space that is available for the fulfilment of the core-requirements. From the core-requirements key parameters can be derived. This analysis establishes the degrees of freedom in the solution space and identifies a number of solution approaches [7]. A systematic analysis of the solution space is necessary since designers tend to be satisfied settling for the first solution that they find and are subject to fixation on old solutions [9, 10] even if they consciously try to innovate. Designers cope with the complexity of design by being example driven in their thinking style and discourse, which leads to more conservative designs [11]. An example from our case study is given in Figure 4. Better handling 1 Solution space Mid-engined car for better mass distribution! Long wheel-base to allocate all major masses within the wheel base! consistent solution approaches II More interesting Drive faster in curves 2 Have a very stiff tub! Level down load! Figure 3 Figure 4. Example for mapping out the solution space For each core-requirement designers need to establish its implications for the entire product. They have to analyse the relations between requirements and product characteristics. This includes the relationships between requirements and product characteristics that can be directly influenced, such as material, number of parts, dimensions, as well as the relationship of the product characteristics with each other. This analysis requires a vision of an optimal system (e.g. according to the laws of physics) and knowledge of the trade-offs that will need to be made between parts of the product. Only designers with great experience can make these assessments and have to be guided by their instincts, because the understanding of the connections is often tacit. While various design methods, such as QFD, can contribute to the understanding of these dependencies there are limitations to their applicability [12]. Therefore it is more important to bring teams of experts together to map out the solution space. Once the space of possible solutions has been found, individual solution approaches can be selected. This has to be an iterative and creative task, since conflicting requirements and product characteristics have to be identified. Solution characteristics must be weighed against

7 each other, against basic-requirements and constraints to assess the adequacy of the solution approach. In the example given in Figure 4, it turned out that, because of the location of the engine, passengers had to be seated further forward and because of requiring a stiff tub, the frame had to be strengthened. As a consequence it became difficult to get into the car with a conventional door - a basic-requirement (purchase rejection factor). Identifying and solving these conflicts can lead to new solution approaches and innovation. In this example the car was designed with a novel door swinging upwards. 4.2 Evaluation of possible solutions Once a solution approach has been identified, the designers must select a suitable starting design and assess the changes that are required to this design. A careful assessment of the impact of these changes on other parts of the product gives a greater understanding of the problems involved and allows a rating of the possible solutions. This rating can also include a long-term view about planning updates to the product. The assessment of the implications of change is a two-stage process: Propagation of change to other parts of the product (II III): Clarkson et al. [6] assess the risk, in terms of likelihood and impact, of a change propagating from one system to another based on an a priori experience value captured from experts. Such an approach gives a first indication of likely change propagation. However, change propagation predication is tricky since the likelihood that change will propagate from one system to the next depends critically on the tolerance margins of key parameters linking these systems [2]. Kleedörfer proposes the estimation of change propagation by team discussion [3]. Change impacts to economical impacts (III IV): Typically only a small number of cost factors are considered to assess the impact of a change, while the consequences of a change in terms of design time, flexibility of the solution and quality of the product are not considered. A balanced analysis to select a solution approach should include all factors relevant to the business and not just cost [3]. 4.3 Trade-off between requirements and impacts Every new design solution will inevitably require a trade-off between fulfilling all requirements and the impact the changes will have on the product. Designers have two choices. They can reduce their requirements, assessing whether the violated requirements are vital, for example bringing out a less attractive car with a comfortable but conventional door. Alternatively, they can develop a new solution that does fulfil both vital and basicrequirements. However, the time and resources to do so are limited. In consequence most products are compromises. 5 Conclusions In industry most new products are developed by modifying existing ones. Innovation is therefore typically a change to a product. Before the design of a new product can begin designers need to carefully assess the requirements for a new solution. Innovation must be targeted where requirements make it necessary, keeping successful solution aspects unless they would have to be changed later as part of a long-term innovation strategy. We propose a two-stage strategy involving a mapping out of the possible solution space based on the

8 requirements and a selection of solution approaches based on an assessment of the impact of the change on other parts of the product, thus assuring the most economical solution. Acknowledgements The authors are grateful to the UK Engineering and Physical Sciences Research Council (EPSRC), GKN Westland Helicopters Ltd and Lotus Engineering for their support of this project. References [1] Gausemeier, J, Lindemann, U, Reinhart, G, Wiendahl, H-P (2000), Kooperatives Produktengineering, HNI, Paderborn. (HNI-Verlagsschriftenreihe; Bd. 79) [2] Eckert, C M, Clarkson, P J and Zanker W (2000), Customisation in Complex Engineering Domains, University of Cambridge, CUED/C-EDC/TR101. [3] Lindemann, U and Reichwald, R (1998), Integriertes Änderungsmanagement, Springer, Berlin. [4] Blessing, L T M and Yates, I R (1999), Design and development capabilities of small and medium sized enterprises in the UK: an analysis, in 12th International Conference on Engineering Design, Munich, Germany, 1, pp [5] Gerst, M, Seidemann, H and Kanitz, F (2000), Kooperatives Produktengineering. Strategische Produkt- und Prozessentwicklung, in: ZWF 95, no. 7-8, pp [6] Clarkson, P J, Simons, C S and Eckert, C M (2000), Change Propagation in the Design of Complex Products, in Engineering Design Conference 2000, Brunel University, UK, June, pp [7] Lindemann, U, Demers, M, Gerst, M and Wulf, J (2001), Lösungssuche mit Hilfe von Zielformulierungen, in: Konstruktion, n. 3. [8] Kano, N, Seraku, N, Takahashi, F, Tsuji, S (1984), Attractive Quality and Must be Quality, in: Journal of the Japanese Society for Quality and Control, 2(14): pp [9] Jansson, D G and Smith, S M (1991), Design Fixation, Design Studies, 12: pp3-11. [10] Purcell, A T and Gero, J S (1996), Design and other types of fixation, Design Studies, 17: pp [11] Eckert C M and Stacey M (2000), Sources of Inspiration: A Language of Design, Design Studies, 21(5): pp [12] Eiletz, R (1999), Zielkonfliktmanagement bei der Entwicklung komplexer Systeme am Beispiel PKW-Entwicklung, Shaker, Aachen. Dipl.-Ing. Manuel Gerst Institute for Product Development Technische Universität München Boltzmannstr. 15 D Garching Phone: Fax: gerst@pe.mw.tum.de