Influence of a micropatterned insert on characteristics of the tool-workpiece interface in a hard turning process

A micropatterned insert leads to decreases in cutting force, the coefficient of friction, and tool wear. This study prepared a pattern on the tool rake surface using layer-by-layer electrical discharge machining. Hard turning was investigated by measuring the cutting forces and chip morphologies. Friction was calculated by modeling continuous and saw-chip formation with various feed rates and surface velocities. Tool wear was measured using the increase in the material removal rate. The micropatterned insert decreased the force by 2.7 ∼ 10.9% compared with the non-patterned insert because the friction was reduced by 9.5 ∼ 34.5% with decreases in the feed rate and surface velocity. In comparison, the flank wear improved by 9.7 ∼ 11.4% for the micropatterned insert compared with the non-patterned insert as the surface velocity decreased. Air gaps on the micropatterned insert cause the friction reduction due to additional shear deformation, escaping wear particles into apertures, reducing the contact area of the tool-chip, and uniform contact stress.