Analyzing the performance of self-developed cermet micro end mills in machining of TC4 alloy micro-grooves

Abstract

A Ti(C7N3)-based cermet micro end mills with a diameter of 0.5 mm has been developed and its cutting edge radius is ranging from 1.63 to 2.08 μm. The micro-cutting performance of cermet micro end mills has been evaluated by comparing their performance with commercial coated WC micro end mills (MXH230, NS Company, Japan) in dry slot milling of TC4 alloy. Tool damage, micro-milling forces, and surface quality of micro-grooves were analyzed exhaustively. It showed that the main wear mechanisms of cermet and coated WC micro-mills were dominated by micro chipping and adhesive wear. And flank wear and the tool coating failure were also found on coated WC micro end mills. The Peak-to-Valley (P-to-V) feed, normal and axial forces using cermet and coated WC micro-mills had a zig-zag pattern of increase with cutting distance. Micro-grooves milled by cermet micro end mills could achieve a higher surface quality with Ra around 92.6 nm and relatively smaller top burr compared with that manufactured by coated WC micro end mills during the whole machining, which was quite difference with the wrong combination of ceramic cutting tool and titanium alloys in macro machining. These results indicated that cermet micro end mills having 0.5 mm diameter were more suitable for micro-milling TC4 alloy than commercial coated WC micro end mills, indicated that the material of Ti(C7N3)-based cermet can be used to commercially fabricate micro end mills to machine TC4 alloy.