Trim Die Damage and "self-Reconditioning" Effect on Trimmed Edge of Sheet Metal Blanks

Abstract

Tooling durability for advance high-strength steels has been investigated by Auto/Steel Partnership at an industrial site using AISI D2 die for trimming DP980 up to 100,000 hits. The topological characterization of the trimmed workpiece edges were measured by a laser confocal microscope that provided 3D surface geometries, and further analysed. It was found that, despite of initial portion of edge roughening and edge quality deterioration from the new trim die, in the majority portion of the trimming operation up to 100,000 hits the edge quality of the trimmed sheet metal edges show combined roughening and smoothing cycles, or called a "self-reconditioning" effect, with the edge quality to be within a stable roughness window. The non-even wear between two pieces of trim die pair and along the die cutting edge is observed and analysed. This finding leads to the need of better redefinition of trim die failure or trim die reconditioning criterion.