Effect of edge radius on forces, tool wear and surface integrity under edge radius dominated tool-chip contact conditions

Abstract

Cutting-edge micro-geometry is a crucial factor influencing chip formation and tool performance. This paper investigates the effects of varying cutting edge radius (36–70 µm) on machinability and chip morphology during finish turning Ti6Al4V. An increase in edge radius decreases the cutting to thrust force ratio and produces lower chip thickness due to the increase in plowing zone depth. The machining temperature for the 48 and 52 µm edge radius tools is lower compared to all other tools. At the initial stage, the edge prepared tools exhibit larger flank wear, whereas subsequent flank wears progression is slower for the prepared tools as compared to the sharp tool. BUE and premature chipping is reduced for larger edge radius tool due to better edge stability provided by cutting edge preparation. Beyond the 59 µm edge radius, the process force, machining temperature, tool wear, and surface roughness increased steeply due to the increase in the size of the plowing zone. In addition to cutting force and machining temperature data, surface roughness, tool wear measurements and XRD analysis show that a radius range of 50–55 µm results in optimum performance for finish turning Ti6Al4V.