THE INFLUENCE OF THE NON-SYMMETRIC PUNCHING PROCESS PARAMETER ON THE HOLE SHAPE AND QUALITY OF A COMMERCIALLY PURE TITANIUM SHEET

Abstract

Recently, punching technology has become one of the promising manufacturing techniques for a thin metallic sheet. The processing parameters used in this technique have been recognized to influence the hole shape produced in the working materials. Therefore, it is important to understand the effect of the punching process parameters on the hole shape and quality over the manufactured materials. This study aims to determine the influence of the punching process on the non-symmetrical hole shape and quality over a commercially pure titanium sheet. The effect of punch speed on the punch force and the sheared surface is also studied, by applying the punch velocities of 10, 35 and 70 mm/s. The sheared surface of the hole was examined at its four different sides, namely K (straight), L (outer radius), N (inner radius) and M (straight). The results show uneven distribution of punch strength as detected at the affected region of the non-symmetrical hole. In addition, the punch force increased with the increase of punch speed. Meanwhile, the sheared surfaces on each side were apparently different. The burnish height on the side of the radius was found to be about 0.038 mm higher than that on the straight side. The burnish height on the radius side increases by 0.43 mm with the increasing punch speed from 10 to 70 mm/s. However, the increased punch velocity did not always increase the burr height. The work hardening that occurs on the straight side is smaller by about 15% than the radius side.