The effects of cutting conditions on cutting temperature and hole quality in drilling of Inconel 718 using solid carbide drills

In this study, the drillability of Inconel 718 has been experimentally investigated under dry, wet, and cryogenic conditions. Drilling tests have been performed at a cutting speed of 15 m/min and a feed of 0.02 mm/rev using TiAlN coated and uncoated solid carbide drills. The effects of cooling/lubrication conditions and coating material on drillability of Inconel 718 are evaluated in terms of thrust force, torque, cutting temperature, hole quality, and tool wear. Experimental results show that cooling/lubrication conditions have significant effects on all performance criteria. Cryogenic cooling significantly reduces the cutting temperatures. Generally, cryogenic drilling exhibits better performance in terms of hole quality and surface integrity. However, it is found that cryogenic conditions increase the thrust force and significantly reduce the tool life due to excessive chippings. Good surface roughness and tool life are achieved under wet conditions. In addition, the use of the coating material also reduces the tool wear dramatically.