A fundamental approach to establishing a rule base for the design of tools for pressworking

Abstract

Software is being developed for use in the design of tools for the multi-stage drawing of small cylindrical cups with some emphasis on cups with medium to large flanges often produced in progression tools; the software is also being used for the rapid estimation of the manufacturing and tooling costs. Attempts are being made to generate the rules from fundamental data on material properties such as the workhardening and plastic anisotropy and the limiting draw and redraw ratios rather than relying completely on data on safe diameter reductions normally elicitated from tool designers and obtained from standard tool design reference books. Computer models which take into account workhardening and planar anisotropy have been developed to estimate the drawing loads in the presence of ironing and to predict forming limits. This paper presents the theory involved in the development of the program for the first stage drawing of plain and flanged cylindrical cups with some results from use of the model.