Product design

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This article is part of the Bachelor design guide; the original version can be found at page 11.

What is product design?

Figure 1: The product: form, properties and functions^[1]

Products are artefacts conceived, produced, transacted and used by people because of their properties and the functions they can perform. Products are used by people because of the functions they fulfill and the solutions they bring to their problems. A product is a deliberately conceived artefact, planned and developed from the drawing board; product design is the process of devising and laying down the plans that are needed for the manufacturing of a product and how it should be used. These plans contain the shape and dimensions of the parts, the materials the parts are to be made of, the manufacturing techniques to be ap­plied and the way the parts are to be assembled into a complete product.

The product

A product is a material system, which is made by people for its properties. Because of these properties it can fulfil one or more functions. By fulfilling functions a product satisfies needs, and this gives people the possibility to realise one or more values.

Form

The geometrical and physico-chemical form that a product must have after the manufacturing process, is the design of the prod­uct.

Properties

Because of its form, a product has specific properties, such as weight, strength, hardness, colour etc. Each property tells us some­thing about the reaction the object will show if we bring it into a specific environment and use it in a specific way. In designing, one is especially interested in the properties, as these directly determine the functioning of the product. Designing is to give the product such a geometrical form that it has the desired properties, and consequently can perform the desired function.

Function

The function of a product is the intended and deliberately caused ability to bring about a transformation of a part of the environ­ment of the product. To realize a goal - a goal is a desired state - something must be changed in our environment. The natural process of change that affects this environment - including ourselves - should be adjusted by the product in a desired direction. Some processes should run differently than it would without the product; a coffee mill changes beans to coffee, a chair supports (prevents one from becoming tired), and a poster provides information (decreases uncertainty). Function is a general term. It refers to the purpose of a product, which is usually many-sided. We can therefore talk about the technical, the ergonomic, the aesthetic, the semantic, the business economic, the social and other functions of a product. The detailed description of the func­tions of a product in all its aspects leads to the design specification; this is the list of all the properties that the product should possess to achieve its function.

Product design as part of the product innovation process

Main article: Product innovation process

The product design process is often presented as part of the product innovation process. The product innovation process describes the activities starting with a strategic analysis, the product design process, the production development and the development of marketing plans. The interaction between the various activities of product innovation process is typically described in these types of models.

Product design described in phase models

Main article: Phase model

The product design process is described as a phase model: a process with various distinct phases (for example, a problem analysis phase and an idea generation phase). The phases correspond to different levels of abstraction of the product idea. These levels correspond to various forms in which a design in the making can be represented, such as the function struc­ture, the principal solution and the preliminary design.

Product design modelled as problem solving

Main article: Basic design cycle

In the third model, the product design process is described as a way of thinking. The design process is seen as a problem-solving model: distinct steps can be distinguished, which together form a cycle. This is called the basic design cycle. The basic design cycle is the most fundamental model of the design process.

Models of the product design process

The literature on product design contains a variety of models of describing and prescribing the design process. A model of design is a theoretical description of the activity of designing. There are three types of models, portraying different viewpoints on the process of designing. The three types of models do not oppose, but they supplement one another in explaining the product design process ^[1]:

1. Product design as part of the product innovation process learns us what aspects should be taken into account when designing new products.
2. The phase models of product design indicate what kinds of problems the product designer has to solve and what the best se­quence is therein.
3. The basic design cycle gives the logical sequence of steps in the problem-solving process within each phase of product designing.

Product design: a multi-disciplinary approach

Product design: concentric development

In the phase models of the product design process the interaction of product design, production development and marketing is not indicated. Commercial and manufacturing considerations are largely seen as constraints (established in the specification), within which the designer seeks the best possible form for the product. Product design is part of the development of a new busi­ness activity, called the product innovation process. Product innovation comprises the design of a product, plus the development of the plans for manufacturing, distribution, and the market approach. All these plans have to be properly attuned to one another. This also demands a phased approach, but with respect to the overall product innovation process. There can only be real interac­tion between development of these plans if the product development process is concentrically phased. In product design there are always alternatives. To find the best one, at least some of them have to be (partially) worked out. In view of the high costs and the uncertainty about the success, it is very important that the development of an unfruitful product idea be stopped as soon as possible. But, beforehand, it is not known whether an idea will be unsuccessful, nor because of what problem, for then one would not have begun with the development of that idea at all. This principal difficulty can only be over­come by dividing a product development project into a number of phases, and to pay attention in each phase to all aspects as much as possible; in the first phases broadly, in order to keep the development costs low, and in later phases increasingly more in depth. At the end of each phase it is to be decided whether an idea will be further worked out in the following phase, whether the phase will be repeated, or whether the idea will be rejected. This principle we have called ‘concentric development’. It is the most important methodological rule for product development; the product development process should be phased concentri­cally, both during product planning and strict development. Therefore the number of phases is rather arbitrary and different for each project. Each following phase augments the certainty that one is on the right track, but the remaining uncertainty as to the ultimate success of the product never disappears completely^[1].

Approaches to the product design process in Delft

Figure 2: Different viewpoints on the product design process at Industrial Design Engineering

At the Faculty of Industrial Design Engineering in Delft, a Bachelor student encounters four different viewpoints on the product design process. The first two, product design as part of the product innovation process and product described as a basic design cycle and as a phase model offer a more general and integral account of product design. Product design described as a form creation process and in the vision in product design model offer a more focussed and explicit account of product design. The fish trap model (form creation) and vision in product design are sometimes considered more of a method rather than a theory of product de­sign. Yet, their scope extends beyond what is considered a method in this design guide. The fish trap model and vision in product design offer a comprehensive view on only a part of the more integral descriptions provided in the product innovation process or the various phase models of the design process. Throughout the Bachelor curriculum a student will encounter these different viewpoints in the courses and course material. These viewpoints are presented in the books in the following list:

Product design as part of the product innovation process

Emphasis in this integral view is on the business activities that support the design of a new product, as described by prof. J. Buijs in his book Integrale Productontwikkeling^[2].

Product design described in the basic design cycle and a phase model of the product design process

Described by N. Roozenburg and J. Eekels in their book Product Design: Fundamentals and Methods^[1]. This integral view is primar­ily concerned with explaining how designers think, and describing the stages of a product design process.

Product design portrayed as a form creation process

Described in the fish trap model by W. Muller in his book Order and Meaning in Design^[3]. This view presents a view on design­ing as a form creation process. It also provides a method for systematically desigining a product form.

Product design described in the vision in product design model

VIP, developed by prof. P. Hekkert and prof. M. van Dijk ^[4][5], presents a different approach to product design, where the focus is more on the context of the interaction of the product with the user(s).

References

1. ↑ ^{1.0 1.1 1.2 1.3 1.4} Roozenburg N. and Eekels J. (1998) Product Design: Fundamentals and Methods, Wiley, Chichester, 2nd ed.
2. ↑ Buijs J. and Valkenburg R. (2003) Integrated New Product Development Lemma, Utrecht
3. ↑ Muller W. (2001) Order and Meaning in Design, Lemma, Utrecht.
4. ↑ Hekkert P. and van Dijk M. (2001) Designing from context: Foundations and Applications of the ViP approach, In: P. Lloyd and H. Christiaans (Eds.) Designing in Context: Proceedings of Design Thinking Research Symposium 5, DUP Science, Delft.
5. ↑ Lloyd P., Hekkert P. and van Dijk M. (2006) Vision in Product Design (VIP): The Warm Bath, Delft.