Problems of multi-step forming sheet metal process design

Abstract

This paper describes a numerical simulation of the deep-drawing process of the multi-operational forming of a compressor cover and its optimization by FEM simulation. Several modified tools were tested by simulation and optimized tool shapes from the point of view of minimum number of operations and optimum thickness changes of the sheet at each stage of metal forming were found. The application of FEM into the metal forming processes is a powerful tool for more economical design and reducing costly trial-and-error processes.

Introduction

A significant improvement can be achieved in process planning and tool design by applying software tools that can realistically simulate material forming processes. More accurate and more realistic simulation in metal forming processes can be performed using the finite element method (FEM). FEM-simulation and -optimization are increasingly important tools for the development of a new or improved known sheet metal forming processes [1], [2], [3], [4], [5], [6]. In view of the needs to minimize production costs, to increase environmental protection and to manufacture products of a defined standard quality, present long and complex processes should be shortened as much as possible.

This paper presents the application of the MARC package to the solution of the industrial problem of the multiple forming of the compressor cover. The traditional methods used by the stamping tool design section of industry did not give good results. The main problem was producing the joggles of the compressor cover necessary to clamping springs (Fig. 1). The producer of the stamping drawpieces factory Hydral in Wroclaw could not solve the problem by deep drawing. The factory uses temporary expensive welding technology for joining the joggles to the cover. Employing process modelling by FEM simulations, the author was able to analyse and optimize the multi-operational deep drawing of the joggle in the compressor cover.

Finally, the tool shapes ensuring the minimum number of operations and optimum thickness changes of the sheet at each stage of metal forming were found.