PERFORMANCE AND TOOL WEAR CHARACTERISTICS OF CUBIC BORON NITRIDE CUTTING TOOLS DURING HARD TURNING OF STEEL

Hard turning has been receiving increased attention because it offers many potential benefits over grinding. One of the requirements for the better utilization of the hard turning process is to get a better understanding about the wear trend and the influence of cutting parameters on tool wear. In this work, cutting experiments were carried out to investigate the tool-wear behavior of CBN cutting tools in turning hardened steels. Experiments were conducted at three varying cutting speeds and the surface roughness of the work piece at various stages of tool wear was measured. The experiments confirm the predominant role of tool flank wear land in controlling the surface roughness in hard turning. As wear land increases the roughness also gradually increases and from the results shows that Ra is less than 1μm at lower feed and depth of cut and all three cutting speed. The tool life index, for the specific tool material work piece combination, justifies high speed operation in hard turning.