There are many different scales or combinations of scales on which manufacturability can be measured:
Binary measures. This is the most basic kind of manufacturability rating: it simply reports whether or not a given set of design attributes is manufacturable.
Qualitative measures. Here designs are given qualitative grades based on their manufacturability by a certain production process. For example, rating designs as ‘poor’, ‘average’, ‘good’ or ‘excellent’. Sometimes such measures are hard to interpret, or are subjective, so that in situations where the designer employs multiple manufacturability analysis tools (for example, one for machining and the other one for assembly) it becomes difficult to compare and combine the ratings from the two systems to obtain an overall rating.
Abstract quantitative. This type of scheme involves rating a design by assigning numerical ratings along some abstract scale. For example, each design attribute was assigned a manufacturability index between 1 and 2 and a total used to compare design alternatives. Just as with qualitative measuring schemes, it can be difficult to interpret such measures or to compare and combine them.
Time and cost. In general, a design’s manufacturability is a measure of the effort required to manufacture the part according to the design specifications. Since all manufacturing operations have measurable time and cost, these can be used as an underlying basis to form a suitable manufacturability rating. Ratings based on time and cost can easily be combined into an overall rating. Moreover, they present a realistic view of the difficulty in manufacturing a proposed design and can be used to aid management in making make-or-buy decisions. These measures may not be directly helpful for determining if the designer has achieved a satisfactory level of manufacturability in the design. To some extent, the target production time and cost can be used by the designer to help him in designing products that meet those targets.
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