Investigation of drillability of Inconel 718

The aim of this study is to determine optimum drilling conditions for Inconel 718 drillability under dry cutting conditions. For this purpose when drilling Inconel 718 with coated and uncoated drills cutting parameters have been explained with graphics and pictures by analizing their effects on cutting forces, surface roughness, hole quality and chip formation. Drilling operation were performed on a CNC vertical machining center using uncoated, TiN and TiAlN coated carbide drills in dry cutting conditions. As a cutting paramaters, four cutting speeds (10, 12.5, 15, 17.5 m/min) and three different feed rates (0.05, 0.075, 0.1 mm/rev) have been used. Blind holes having 8 mm depth were drilled with 5 mm drills using this cutting parameters. Cutting forces, surface roughness, hole diameter and ovalibility were measured and the evaluated. By comparing the cutting tools according to these measurement. The best performance was obtained from uncoated cutting tools when drilling Inconel 718 under dry cutting conditions. On the other hand, the worst results were reached from TiAlN coated cutting tools. It was observed that cutting tools performance and hole quality decreased in the combinations of high cutting speed and feed rate.Key Words: Inconel 718, drilling, hole quality, surface roughness