INVESTIGATION OF MICRO MILLING FORCES FOR ALUMINUM

摘要

An efficient micro manufacturing process is required to fabricate miniature components that meet customers' demands. Micro end milling offers a high rate of material removal while being able to create the same complex geometries seen in its macro counterpart. A great deal of knowledge about macro end milling has been collected over the years; however, this knowledge does not directly translate to the micro realm. This paper examines a method to predict the micro mechanical milling forces for aluminum workpieces. In micro milling operations, the critical chip thickness determines whether a chip will form or not. This can be translated into two cutting regimes, which are the shearing dominant cutting and plowing dominant regimes. The shearing dominant cutting regime is modeled as a conventional macro model by identifying appropriate cutting constants. The edge coefficients are found to be considerably smaller than results from macro milling operations. For the plowing dominant regime, the forces are empirically modeled based on experimental tests. Various experimental tests were performed to verify micro milling forces for Aluminum 7075. Measured high frequency vibrations correspond with the first and second modes of the micro tool for both shearing and plowing dominant regimes.