Fast support layout optimization

Abstract

Machining-fixture supports are used to increase workpiece rigidity. A critical problem of machining-fixture design is where to place a fixed number of supports in order to minimize workpiece deformation during machining. This paper presents the Fast Support Layout Optimization (FSLO) model. The objective of the FSLO model is to determine support locations that will minimize the maximum displacement-to-tolerance ratio of a set of workpiece features subject to a system of machining loads. The FSLO model utilizes a Finite Element Analysis (FEA) model to characterize workpiece stiffness. Solution of the FSLO model improves an existing support layout by systematically altering the boundary conditions applied to the FEA model. The FSLO model is unique in that its solution time is both very small and insensitive to the size of the FEA model, the sizes of machined features considered, and the sizes of the candidate regions of the supports. In addition to describing the formulation of the FSLO model, this paper describes a set of experiments that were used for its verification.