Experimental investigations for a simulative optimization of the cutting edge design of twist drills used in the machining of Inconel 718

Many of the properties that determine Inconel 718 for the use in high-temperature applications also make it hard to machine at the same time. In order to improve the drilling tools' life span by a modification of the flank face, finite element simulations have to be carried out that require precise input data from real machining experiments. In this work, investigations that examine the occurring mechanical loads alongside the tool's cutting edge were combined with analyses of the tool's contact zones. It could be shown how the distribution of mechanical loads differs along the cutting edge and how the occurring forces increase as larger parts of the cutting edge come into engagement. The experiments' results lead to the conclusion that the length of the tool-workpiece contact zone is linked to the applied feed rate and that material smearing occurs almost exclusively on the tool's rake face. The gathered results will later allow simulations to develop an optimized tool design implementing a new cutting edge geometry.