A Comparison of Rapid Fabrication Methods for Sheet Metal Forming Dies

Abstract

The need for rapid, low-cost die fabrication and modification methods is greater than ever in the sheet metal forming sector of industry. Consequently, three fabrication methods, suitable for rapid die development schemes, are being compared experimentally based on cost, lead-time, shape resolution and flexibility issues. The candidate methods include CNC-machining a solid billet of material (standard method), assembling and clamping an array of profiled-edge laminations (PEL), and configuring and clamping a matrix of closely-packed pins (discrete die). A matched-set of forming dies was made using each of the candidate fabrication methods for stamping an FEA-verified benchmark part out of steel sheet. Based on the stamping experiments, a PEL die is shown to be similar to CNC-machined dies except that most tooling accessibility problems are eliminated, die geometry limitations are reduced and faster fabrication is possible for harder tool materials. When compared with CNC-machined dies, the discrete die method limits part shape fidelity, maximum forming loads, die geometry and blankholder incorporation. However, the discrete die method excels over the other two methods in terms of lower cost and faster fabrication time. The results of this study make a strong case for the sheet metal forming sector of industry to actively implement the PEL and discrete die methods in their manufacturing operations.