In this paper, we present an approach to recognize symmetries of sheet-metal parts at different manufacturing stages. We show, by recognizing that the part is symmetrical, that the planning complexity for processes in sheet-metal production can be greatly reduced. This paper is motivated by the fact that a significant percentage of sheet-metal parts are symmetrical. We have studied over 200 industrial parts and over 40% of them are symmetrical. Examples from sheet-metal nesting (layout), bending, stacking, decomposition and assembly planning are discussed.

C.-H. Wang and D. A. Bourne, ``Using Symmetry to Reduce Planning Complexity:A Caes Study on Sheet Metal Production'' to appear in ASME Design for Manufacturing Conference (ASME97-DETC), Sacramento, 1997.