Micromilling of metal alloys with focused ion beam-fabricated tools

This work combines focused ion beam sputtering and ultra-precision machinin g as a first step in fabricating metal alloy microcomponents. Micro-end mil ls having similar to 25 mum diameters are made by sputtering cobalt M42 hig h-speed steel and C2 micrograin tungsten carbide tool blanks. A 20 keV focu sed gallium ion beam is used to define a number of cutting edges and tool e nd clearance. Cutting edge radii of curvature are less than or equal to 0.1 mum. Micro-end mill tools having 2, 4 and 5 cutting edges successfully mac hine millimeter long trenches in 6061-T4 aluminum, brass, 4340 steel and po lymethyl methacrylate. Machined trench widths are approximately equal to th e tool diameters, and surface roughnesses (R-a) at the bottom of micromachi ned features are similar to 200 nm. Microtools are robust and operate for m ore than 6 h without fracture. Results from ultra-precision machining alumi num alloy at feed rates as high as 50 mm/minute and an axial depth of 1.0 m um are included. (C) 2001 Elsevier Science Inc. All rights reserved.