Precision Shearing Using Zero-Clearance Dies Equipped with Polycrystalline Diamond Tools

Abstract

Tab leads used as the terminals of laminated-type lithium-ion batteries are fabricated by cantilever-type shearing of aluminum sheet coils. There are several drawbacks in the shearing of tab leads owing to the effect of tool wear, such as an increase in burr height at the cut surface with increasing number of shearing passes. To solve this problem, we designed and fabricated a zero-clearance cantilever-type shearing die equipped with high-wear-resistance polycrystalline diamond (PCD) tools (a punch and a die) (Die 1). The die has a mechanism that can prevent the increase in the clearance of the punch and die during shearing. We also designed and fabricated a zero-clearance blanking die used for the precision blanking of foils (Die 2). The demand for foils as materials used for electronic devices has been expanding recently. Die 2 was fabricated by shaving the side of a powder-alloy die using a PCD punch. The results of a shearing experiment using Die 1 indicate that the height of burrs generated during the cantilever-type shearing of aluminum sheets can be suppressed to 5 µm or less. Moreover, the results of a blanking experiment of 20 µm-thick stainless-steel foils using Die 2 reveal that a high-precision cut surface can be obtained over the entire blanked contour.