Effects of Tool Wear on Surface Integrity of Aluminum Alloy Machined in Ultra-Precision Cutting Process (2nd Report)

Abstract

Ultra-precision cutting of soft metals is mainly used for generating reflection surface of optical equipments. Accordingly roughness of machined surface is very important evaluation item in quality because the roughness affects performance of the optical equipments. Workpieces are actually machined with a worn diamond tool in machining shops whereas ultra-precision cutting with a single crystal diamond tool is well known as a machining method owing high quality finished surface to a sharp cutting edge of the tool. The purpose of this study is to find out the relation between tool wear and surface roughness machined with a worn tool in ultra-precision cutting process. Profile of a machined surface was measured at intervals of a fixed cutting distance, and profile curves in cutting and feed directions were investigated by using spectrum analysis. As a result of experiments and considerations, we reached the following results. (1) Cutting tool vibrations induced by tool flank wear increased roughness of machined surface in cutting direction and also increased roughness in feed direction. (2) Deterioration of copying of cutting edge shape decreased surface roughness in feed direction. (3) Surface roughness generated by tool vibrations exponentially increased with increase in flank wear of cutting edge generating finished surface.