The Design Process - Medical Device Design: Innovation from Concept to Market - page 30

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Information: adapt specification

Overall flow of project development

Figure 3.4
Design model adapted from Pahl and Beitz (2007).

of the regulatory bodies (like a glove). However we must still integrate with graphics
designers, product designers, etc. and as such we will also look at how to bring these into the
“engineering design family.”

3.2.1 Pahl and Beitz, and Pugh
Figure 3.4 illustrates Pahl and Beitz's 4 model for the design process (originally from the
1980s). It is nearly 30 years old and is starting to show its age. But, the basic concepts are still
worthy of investigation. This and the following model by Pugh are linear processes; that is,
they fundamentally assume that the process starts at one end and moves in a (roughly) straight
line to the final outcome.

Figure 3.4 illustrates an interpretation of the design model proposed by Pahl and Beitz. It is,
as described earlier, linear in approach. The very left end is the start of the process and this is
universally known as the need . There are some who call this the brief , but this is a term often
used by product designers. In essence they are both the same; they give a first description of
the concept.

The second phase concerns the development of the first main design document - the
specification. The third phase concerns developing a concept and an initial layout, leading to
the selection of a single front-runner. This in turn leads to the definitive layouts and finalizing
documentation.

4 Pahl and Beitz's text is in continual print - translated from the German original - and is in its third edition.