An investigation on the performance of bio-mimicked rake surface structured tool during machining of hard-to-cut materials

Abstract

The current work seeks to improve the machining characteristics of tool by generation of various geometrical structures on cemented carbide tool's rake face. A total of three different structures: (a) bio-mimicked micro-crescent structure, (b) micro-dimple structure, and (c) micro-groove structure, are generated using laser micro-machining technique on rake surface of tool. Dry turning tests were performed using the structured tool and conventional tool during cutting of AISI 420 workpiece material. The effect of various geometrical textures on chip-tool contact area, surface roughness, cutting force, morphology of chip and residual stress have been compared with respect to conventional tool. Results indicate that crescent-shaped bio-mimicked structured tool indicated better cutting performance in decreasing contact area of chip-tool by 43.6%, tangential force by 15.38%, feed force by 20.22%, and average surface roughness by 8.81% relative to the conventional tool. The machined surface of structured tool also indicated lower generation of residual stress of 419.3 MPa in cutting direction and 316.9 MPa in feed direction relative to 608.3 MPa in cutting and 375.5 MPa in feed direction using conventional tool machined surface. Segmented chips were produced during all machining conditions, and crescent-shaped structured tool indicated least chip reduction coefficient of 1.08 compared to 1.57 in the case of conventional tool. The results of the current study are very essential for expanding the application of bio-mimicked structured cutting tools for cutting different hard to machine materials.