Fabrication of high-quality microflexures using micromilling techniques

Abstract

This research focuses on the feasibility of using micromilling as a process for fabricating the flexural body of mesoscale nanopositioners. A desire to fabricate non-silicon microflexures for more favorable material properties and flexural responses has led MIT's Precision Compliant Systems lab to investigate the use of various metals in the design of mesoscale six-axis HexFlex nanopositioners. Micromilling is being sought as an alternative method of manufacturing HexFlex flexural bodies due to its inherent process and material flexibility. Cutting forces were approximated (and verified using FEM and previously-measured results) in order to select cutting parameters that would avoid tool failure and ensure workpiece integrity. Several HexFlex devices were successfully micromilled from various aluminum alloys. Total machining time, including setup and tool changes, was around 1.5 hours per part. The integrity of each part was verified using optical microscopy and white-light interferometry to inspect for any microcracks or otherwise unfavorable by-products of the milling process. Ultimately, it was shown that micromilling is a feasible process for manufacturing low-volume to-spec mesoscale nanopositioners (±3 [mu]m) with surface roughnesses of less than 0.300 [mu]m. Process improvements are suggested based on observations before and during the machining process.