Sliver Generation Reduction in Trimming of Aluminum Autobody Sheet

Abstract

Aluminum autobody sheets produce appreciable amounts of slivers during trimming operations when trimmed with dies conventionally designed for steel sheets. The slivers can be carried through downstream processes and cause damage to the surface of formed parts resulting in costly manual repair. This paper reports a systematic experimental study at both the macro- and micro-scale of the sliver generation problem with relation to cutting angle, clearance, and blade sharpness. It is concluded that slivers can be reduced or even eliminated by modifying the current trimming tools designed for steel sheets. The most striking finding is that the conventional wisdom of 0-degree cutting conditions generate the largest amount of slivers for aluminum alloy sheets. With proper cutting angles, trimming aluminum autobody sheets can actually be more robust than that for steel sheets—the clearances can be less restrictive and tools may require much less frequent sharpening. The microscopic investigation traced the origins of slivers and revealed the mechanisms of sliver generation. The paper demonstrates that the integration of material microstructure and mechanics is very beneficial for solving a significant manufacturing problem and can greatly improve the process of shearing aluminum alloy autobody sheet.