SEED Guides Selecting Manufacturing Processes < >

Consider the problem of a designer wanting to know which manufacturing process to specify for the manufacture of a tub shaped product of 2mm uniform thickness, 1m length and 0.5m in depth and width made from a thermoplastic with an annual production quantity of approximately 5,000.

The PRIMA selection matrix in Figure 6 shows that there are four processes considered economically viable given this level of detail.

These are:

• Injection moulding [2.1]
• Compression moulding [2.2]
• Vacuum forming [2.3]
• Blow moulding [2.4]

The designer would then proceed to each selected PRIMA comparing product requirements against relevant PRIMA data in detail. Figure 7 shows a summary of the important data for each process. After examination, vacuum forming would be chosen as it is suited to the manufacture of tub shaped parts of uniform thickness within the size range required. Vacuum forming is also relatively inexpensive compared with the other processes selected by the matrix. It has low to moderate tooling, equipment and labour costs, with a high production rate up to medium volumes making it very competitive.

In summary, the PRIMA selection matrix identifies the potential candidate processes, however, it is the PRIMAs themselves that guide final selection based on detailed technical data and economic requirements.