ABSTRACT
An integral part of design for manufacture is the early selection of material and process combinations for the manufacture of parts, which can then be ranked according to various criteria. Unfortunately, designers tend to conceive parts in terms of the processes and materials with which they are most familiar, and they may, as a consequence, exclude from consideration processes and process/material combinations that might have proved to be more economic. Opportunities for major manufacturing improvements may be lost through such limited selections of manufacturing processes and the associated materials in the early stages of product design. This can be well illustrated by the results of a survey of designers’ knowledge of manufacturing processes and materials carried out in Britain [1]. This survey covered a wide range of design offices in various sectors of industry. For manufacturing processes (Figure 2.1), more than half of those surveyed professed little or no knowledge of metal extrusion, two-third knew little about glass-reinforced molding, and over three quarters were uninformed about plastic extrusion, sintering, and the use of thermoset polymer fiber-reinforced sheet-molding compounds (SMC) and bulk-molding compounds (BMC). For less common processes, such as hot isostatic pressing, outsert molding, and superplastic forming, the percentage of designers claiming some process knowledge was only 6, 7, and 8, respectively. Similar results were found for materials, and Figure 2.2 illustrates designers’ knowledge about a range of polymeric materials. This again shows a surprising lack of familiarity with some commonly used materials. The overall implication of these findings is that because material and process combinations are likely to be chosen from those with which designers are most comfortable, the possibilities of using other processes that may be much more cost-effective may be missed.
