Micrometer-scale machining: tool fabrication and initial results

• Published in: Precision engineering Vol. 19; no. 2; pp. 180 - 186
• Main Authors: Vasile, Michael J., Friedrich, Craig R., Kikkeri, Bharath, McElhannon, Rob
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.10.1996; Elsevier Science
• Subjects: Applied sciences; Control systems; Exact sciences and technology; Fabrication; Geometry; Mechanical engineering. Machine design; micromachining; microtools; Milling machines; Numerical methods; Precision engineering; Precision engineering, watch making; ultraprecision; micromachining; microtools; ultraprecision; Manufacturing process; Milling cutter; Precision engineering; Micromachining; High precision; Ion beam; Methyl methacrylate polymer; Cutting tool; Miniaturization
• ISSN: 0141-6359; 1873-2372
• DOI: 10.1016/S0141-6359(96)00024-4

Conventional milling techniques scaled to ultrasmall dimensions have been used to machine polymethyl methacrylate (PMMA) with micrometer-sized milling tools. The object of this work is to achieve machining of a common material over dimensions exceeding 1 mm while holding submicrometer tolerances and micrometer size features. Fabricating the milling tools themselves was also an object of the study. A tool geometry for nominal 25 micrometer diameter cutting tools was found that cuts PMMA with submicrometer tolerances over trench lengths of 2 mm. The tool shape is a simple planar facet cut by focused ion beam milling on ground and polished 25 micrometer diameter steel tool blanks. Pairs of trenches 24 micrometers wide, 26 micrometers deep, 2.3 mm long, with a 14 micrometer separation were milled under various machining conditions. The results indicate that the limits of the machining process in terms of speed, pattern complexity, and tolerances have not been approached. This is the first demonstration of a generic method for microtool making by focused ion beam machining combined with ultraprecision numerically controlled milling. The method is shown to be capable of producing structures and geometries that are considered inaccessible by conventional materials removal techniques, and generally regarded as applications for deep X-ray lithography.