Effect of Cutting-Edge Geometry on the Machinability of 316L Austenitic Steel

The paper focuses on the problem of selecting the correct tool geometry in high-speed milling of 316L stainless steel. Carbide milling cutters with two configurations of helix angle (40/42 degrees for tool#1 and 35/38 degrees for tool#2) with different cutting edge radiuses rn (i.e. 4 µm, 6 µm, 8 µm, 10 µm and 12 µm) were prepared and their impact on cutting force and roughness were analyzed. The obtained results revealed that the small changes in cutting edge radius rn have a significant effect on both cutting forces and surface roughness. In this context, irrespective to the type of the tool, increasing the cutting edge radius results in further cutting force. However, increasing the cutting edge radius shows different behavior on roughness while using different tool helix angles. For the tool#1, it was found that the surface roughness increases by increasing the cutting edge radius from 6 μm to 12 μm; while in the samples machined by tool #2, increase in cutting edge radius results in reduction of roughness. It was also found that irrespective to the values of cutting edge radius, the cutting force while using tool #1 is slightly less than the tool#2. In addition, the induced milling surface roughness of the samples machined by tool#2 is significantly less than the tool#1 where the mean value of Ra was reduced from 2.55 µm to 0.35 µm.