Читать книгу Computer Aided Design and Manufacturing - Zhuming Bi - Страница 19

A manufacturing system is understood from the technological and economic perspectives. Technologically, a manufacturing system is to transform raw materials into final products via a set of operations. Economically, a manufacturing system is a process to add values to final products via a set of economic transactions associated with manufacturing processes. Making a profit is always a primary goal to entrepreneurs. The profit can be maximized in two ways: (i) to reduce costs on no value‐added activities and (ii) to increase the sale price by providing a corresponding value to the customer.

Engineering design plays a significant role in implementing these two strategies. Figure 1.7 shows the impact of the activities of design, manufacturing processes, raw materials, management, and marketing on the overall product costs. The impacts are measured by the percentages of overall product cost affected by the activities in a certain category. Even though the minimal percentage of the actual cost is related to the design activities, they mainly affect the overall product cost.

Figure 1.7 Significant impact of design activities on overall product cost.

In Figure 1.8, the value‐added chain smile curve by ITC (2019) shows the importance of design effectiveness on the possibility of added values of products in contrast to competitors. Business activities in a manufacturing system can be classified based on its involvement with hardware systems. The more dependence on hardware systems, the less chances a company gains in competitiveness on adding more values to products. Along with the product lifecycle, the more design activities are involved, the better the chances to gain competitiveness by adding more values of products than competitors.

Figure 1.8 Value‐added chain smile curve (IEC 2019; ITC 2019).

The importance of engineering design can also be reflected by the additional costs a company may spend to fix some defects and errors occurring to different phases of a product lifecycle. The first‐time correct is an idea goal to make highly diversified products and can only be achieved when CAD tools are capable of eliminating all of the design defects at the design stage. Figure 1.9 shows that, conventionally, the errors with a 75% fixing cost are made at the design stage of products, but the errors fixed at the manufacturing stage or later take around 80% of the fixed cost. It is clear that the earlier an error or defect is identified, the less cost is needed to fix it.

Figure 1.9 Relative costs to fix errors at different phases of product lifecycle.