Taguchi Method Based Process Space for Optimal Surface Topography by Finish Hard Milling

Abstract

Hard milling has a potential to replace finish grinding in manufacturing dies and molds. Surface finish is one key surface integrity parameter to justify the use of hard milling. In this study, a Taguchi design-of-experiment based finish milling hardened AISI H13 tool steel (50±1 HRc) with physical vapor deposition (PVD) (Ti, Al) N–TiN-coated end mill was conducted to investigate the optimal surface topography and roughness. A kinematic model of the cutting tool loci was developed to investigate the formation mechanism of the surface texture and correlate the simulated surface textures with the measured ones. The milled 3D surface topography and anisotropic roughness in the feed and step-over directions were thoroughly characterized and analyzed. The milled surface roughness Ra of less than 0.1 μm in the feed direction and 0.15 μm in the step-over direction has shown that hard milling is capable of replacing grinding as a finish or semifinish process. Furthermore, the process parameter spaces for the desired surface properties were indentified via the surface contour maps.