High speed end milling of cobalt chromium molybdenum alloy using solid carbide tool under MQL condition

Abstract

Cobalt chrome molybdenum (CoCrMo) alloy is among the biomedical materials which is considered difficult to cut materials due to their combination of high strength, high toughness, high wear resistance, and poor thermal conductivity. In this study, high speed end milling (HSEM) was performed experimentally to access the machinability of CoCrMo alloy using solid coated and uncoated tools at different cutting speeds of 125, 140 and 155 m/min under the minimum quantity lubricant (MQL) strategy. The axial and radial depth of cut were kept constant 4 mm and 1.5 mm respectively throughout the machining tests. The tool wear, tool life and tool wear mechanism were recorded and analyzed accordingly. It was observed that higher cutting speed significantly reduces the tool life due to rapid tool wear. Coated carbide tool performed better than uncoated carbide tool in terms of tool life for every cutting speed. It was also found that chipping, adhesion and cracks were the dominant wear mechanisms occurred on the cutting edge when high speed end milling of CoCrMo biomedical material.