Tools of Change

Abstract

This article discusses reconfigurable forming dies that increases the efficiency of small-lot production. Manufacturers have long desired single universal tools that could make many different shapes. Patents for reconfigurable “discrete-die” tooling—dies composed of movable elements such as pins or plates—date back nearly to the inception of the patent office. In forming large sheet metal parts, elastic springback can cause unacceptable part shape errors if the part is formed on a tool whose shape mirrors that of the finished part. Two approaches to tool shape correction have been developed for use with the reconfigurable tool. In one, an iterative technique calculates the correct die shape based on two initial guesses. In the other, a predictive technique uses finite element analysis to model and correct for elastic springback. Cost and benefit analysis has shown the attractiveness of reconfigurable tooling based on the initial investment alone. An even greater benefit could be realized through lowered assembly costs and shortened turnaround time for small production lots. Small-lot production shops are likely to profit by replacing fixed-shape forming tools with reconfigurable tools.