The micro-cutting performance of cermet and coated WC micro-mills in machining of TC4 alloy micro-grooves

Compared with commercial CrTiAlN-coated WC micro-mills, self-developed Ti(C7N3)-based cermet micro-mills were evaluated by milling of TC4 alloy micro-grooves. Tool damage, micro-milling forces, and surface quality of micro-grooves were analyzed to examine the cutting performance. The main wear mechanisms of cermet and WC micro-mills were dominated by micro-chipping, flank wear, built-up edge, and adhesive wear. Except for these failure modes, coated WC micro-mills had broken. The peak-to-valley (P-to-V) feed and normal forces using the coated WC micro-mills were much higher than cermet micro-mills. And micro-grooves milled by cermet and coated WC micro-mills achieved a good surface roughness. The top burrs were first found at the cutting distance of 12 mm using cermet micro-mills, but the top burrs appeared during the entire machining using coated WC micro-mills. These results indicated that cermet micro-mills were more suitable for micro-milling TC4 alloy than coated WC micro-mills.