The Effects of the Drill Microgeometry on the Induced Thrust Force and Cutting Torque

Microgeometry plays a key role in the performance of a drilling tool. In the present study, the performance of two twist drills is being evaluated in terms of the generated cutting force and torque. Both tools are ø8 TiAlN coated, carbide two-flute drills, with a point angle of 140°, as well as with equal flute length. A plate of Al7075 served as the workpiece and a CNC machine was utilized to perform two sets of holes, one for each of the tools. Despite the fact that both tools are coated, with identical helix and point angles, they performed in a dissimilar manner due to their different cutting profile. In specific, the comparison revealed that the tool with the larger cutting lip performed better in both output data, yielding lower force and torque values up to 23.1% and 17.3% respectively.