Surface Integrity in Ultrahigh Speed Micromachining

A new ultrahigh speed micro-spindle was used for micro-milling and micro-grinding at speeds greater than 300,000 rpm. Micro-milling was performed on an aluminium alloy with micro-end-mills ranging in diameter from 50 to 300 μm. The dimensional accuracy of straight cuts made at different speeds, feed rates and depths of cut was measured. The edge quality improved and burr formation tendency decreased as surface speed and feed rate were increased. Micro-grinding was performed with diamond tools on ceramics used for preparation of dental restorations. The propensity for generation of machining-related damage, such as surface and subsurface microcracks, were greatly reduced by machining at ultrahigh speeds and high feed rates. Major advantage of ultrahigh speed machining is the improvement of surface integrity with respect to generation of burr-free and damage-free micro-machined parts.