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Chapter 6
with Vaseline they considerably reduced the number of paint stains on the atomizer. When the laboratory was questioned on the subject, it explained the phenomenon but was unable to suggest a simulation that could lead to new, practical solutions. The designers therefore came to this conclusion: “We have to try. We have to build a prototype.” A few years earlier, ideas took shape in the workshop first before they were tested; the designer developed the prototype and tested it himself. His expertise was based on this ability to create extremely short test-error loops between the drawing board and prototype testing. Nowadays, the development of prototypes is, to a great extent, contracted out. It has also become more complex. The design-development-test loop is longer. Nevertheless, it is still one of the outstanding features of this design office. The designer and the subcontractor in charge of developing the prototype are in almost continuous contact. Moreover, the designers are familiar with manufacturing processes. The Specific Status of Prototypes The prototypes, once they are back from the manufacturer’s plant, do not follow standard part acceptance procedures. The “quality control” technicians who are supposed to check that they are compliant with plans merely set them aside for the design office. Besides, quality control is all the more difficult because the plans available to the controller are not up to date, as changes made during development are validated with the design office by telephone and are not added to the plans. Prototypes are modified many times during development. Therefore, thanks to time considerations, trust, and habit, the procedure defined by the company for the acceptance of orders is bypassed. Technicians are, moreover, remarkably impatient when they are waiting for a prototype. As soon as it arrives, they will not rest until they have tested it to validate their theories. When a part arrives, they hunt down all the elements needed to put the prototype together: they take standard parts from the shop and tools from their co-workers; they go into offices and workshops to find what they want. They assemble the prototype in the laboratory and on the test bench. They check, first of all, that “it works.” You can see the apprehension on their faces as they set the spindle up on the test bench. Seemingly relaxed glances and smiles betray their nervousness. Then they ask the laboratory technicians to carry out more advanced validation tests. These tests are a fundamental part of the design process. Their purpose is to qualify and validate theoretical technological solutions. They