Deformable sheet metal fixturing: Principles, algorithms, and simulations

Fixture design is an important consideration in all manufacturing operations. Central to this design is selecting and positioning the locating points. While substantial literature exists in this area, most of it is for prismatic or solid workpieces. This paper deals with sheet metal fixture design. An ''N-2-1'' locating principle has been proposed and verified to be valid for deformable sheet metal parts as compared to the widely accepted ''3-2-1'' principle for the rigid bodies. Based on the ''N-2-1'' principle, algorithms for optimal fixture design are presented using finite element analysis and nonlinear programming methods to find the best ''N'' locating points such that total deformation of the deformable sheet metal is minimized. A simulation package called OFixDesign is introduced and numerical example are presented to validate the ''N-2-1'' principle and optimal sheet metal fixture design approach.