An investigation on surface finishing in ultra-precision raster milling of aluminum alloy 6061

Abstract

The technology of ultra-precision machining with single crystal diamond tool produces advanced components with a higher dimensional accuracy and a better surface quality. This article develops a three-dimensional surface topography simulation model for ultra-precision raster milling process by considering the effect of cutting parameters, tool geometry and tool interference as well as the tool–workpiece relative movement on surface generation. Based on the developed surface topography simulation model, a prediction model for the surface roughness in ultra-precision raster milling is built. The effects of depth of cut and surface topography on the cutting-induced heat generation in ultra-precision milling of aluminum alloy 6061 are investigated. Experiment is conducted to verify the developed surface topography simulation model by raster milling of aluminum alloy 6061 under different feed rates and depths of cut. The experimental results show that the surface topography simulation model can properly simulate the surface profile in the raster milling process and the predicted surface roughness agrees well with the measured results of the machined workpiece. Heat generation in horizontal cutting is less than that in vertical cutting and a larger depth of cut generates more heat on the machined workpiece. The cutting-induced heat generates precipitate on the machined aluminum alloy 6061 which results in a worse surface finish in ultra-precision raster milling.