PERFORMANCE STUDIES OF COATED TOOL INSERTS DURING HARD MACHINING

Abstract

The progress in manufacturing technologies has driven the need for enhanced cutting tool materials and coatings, capable of meeting the challenges of high-speed and high-precision machining of hard materials. This research aims to improve the performance and sustainability of cutting tools used in hard machining applications by developing, characterizing, and applying magnetron sputtered PVD coatings on ceramic cutting tool inserts. The primary objectives are to enhance the hardness, adhesion, and tribological properties of these coatings by strategically doping them with different elements, and to thoroughly assess the cutting performance of both coated and uncoated tools across various cutting parameters. Ceramic cutting tools are highly valued for their exceptional hardness and thermal stability. However, their performance can be greatly improved by applying advanced coatings. In this study, TiN and CrN thin films were deposited onto ceramic inserts using magnetron sputtering, a versatile physical vapor deposition (PVD) technique known for producing uniform and strongly adherent coatings. These coatings were then doped with specific elements to optimize their mechanical and tribological properties. TiN coating was doped with vanadium (V) to form TiVN coating and CrN coating was doped with titanium (Ti) to develop CrTiN coating onto SiAlON ceramic cutting tool inserts. The hardness and adhesion of the coatings were evaluated using nanoindentation and scratch tests, respectively, while Field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) were used to analyze the coating’s microstructure and phase composition. Furthermore, Energy dispersive X-ray spectroscopy (EDS) was utilized to validate the elemental composition of the coating present on the substrate.