Differentiation sequence in the manufacturing process. Figures 2 and 3 show design charts for variety manufacturability of mi- crowave ovens. Figure 2 plots commonality against VVOC, a number derived from quality function deployment. Figure 3 plots commonal- ity against stages in the manufacturing line. The charts pinpoint weaknesses in a product line and guide the designers to improved modularization.
Ongoing work attempts to quantify more accurately the cost of providing variety.
The second perspective addresses both serviceability and reliability. During the design process, the engineer needs to break into priorities the serviceability in terms of functional importance. DFV Chart 2 Commonality versus manufacturing process sequence. Reliability versus maintenance trade-offs. Accessibility of components requiring service.