Analysis of high speed drilling AISI 304 under MQL condition through a novel tool wear measurement method and surface integrity studies

Abstract

Drilling of SS 304 under dry, flood, and MQL at a relatively high cutting speed of 90 m/min and feed of 525 mm/min is studied. A novel flank wear measurement method is developed for accurate measurement of total drill flank wear - as the sum of the conventional flank wear width and the material lost due to erosion of the cutting edges. Comprehensive surface integrity analysis for machining under such “high speed” – micro-hardness, local plastic deformation on the hole wall surface, surface roughness, and surface irregularities, exit burr - is reported for the first time. The presence of “piercing” type material removal near the drill exit is revealed for dry and flood machining. The tool life, cutting force, drilled hole diameter error, and chip morphology are also analyzed. MQL produces a machining performance often exceeding that of flood lubrication with respect to several machinability parameters considered in this study.