Micro-orthogonal Cutting of Metals

Abstract

High speed micromilling with single point or multi-edge cutting tools of diameters smaller than 300 m is finding increasing applications for the production of small very precise metallic parts. Because of the small value of the ratios cutting depth to cutting edge radius and cutting depth to characteristic microstructural dimensions, one may expect that the extensive technological data base available for conventional metal cutting, may not directly transfer to micromilling and that size effects will influence the cutting pressures in micromilling as compared to those in macromilling. To address this issue, we have developed a micro-orthogonal cutting test facility in which chip thickness can be controlled to within a few microns and cutting forces can be measured. Using this facility, we are conducting a rather fundamental investigation of micro cutting processes to identify possible size effects. Besides measuring specific cutting pressures, we also aim at identifying mechanisms of chip formation and how they are affected by microstructure, fracture damage accumulation and microtool geometry. We intend to contrast these observations with observations made in macro orthogonal cutting of the same materials as those tested in micro orthogonal cutting. This paper will describe the test facility and present preliminary results obtained during micro-orthogonal cutting experiments.