A wide variety of products are manufactured from raw materials that are in the form of sheets or plates. Once the product is designed, parts are unfolded or flattened into flat blanks, which are nested onto the raw material for cutting. Optimization of nesting and packing problems has been an active research field for many years, and many good algorithms have been created. These algorithms have a fundamental limitation, however, in that they assume the set of blanks to be nested is fixed. In this work we relax this assumption, and by linking a parametric CAD system, a part-unfolding module and a sheet-nesting module that all intercommunicate, nests are created which maintain the parametric dimensions of the assembled product. Given a nest of the set of required blanks, dimensions of the blanks are optimized for a particular objective, such as maximizing raw material utilization or minimizing total use of raw material, subject to assembly, part dimension, part and blank dimension constraints. Once optimized, these blank dimensions are returned to the CAD system to update the product model. Through the use of this system, a designer can simultaneously optimize all the dimensions within a product to minimize manufacturing costs early in the design phase while maintaining acceptable product performance. This paper will demonstrate a prototype of this DFM system, discuss issues such as performance improvement through randomized trials, and suggest how additional design objectives (e.g., strength to weight ratio, stiffness, etc.) can be integrated with the reduced manufacturing cost objective.

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