Effect of workpiece material on surface roughness in ultraprecision raster milling

This article presents theoretical and experimental investigations into the effect of the workpiece material on surface roughness in ultraprecision raster milling (UPRM). The influence of material elastic recovery on chip thickness and surface generation in UPRM is studied. A holistic surface roughness prediction model is developed by considering the influences of cutting parameters, tool geometry and the material elastic recovery on surface generation. The experimental results show that the proposed surface roughness prediction model makes a more precise prediction by adding the elastic recovery rate as a material factor, and the presence of elastic recovery improves the surface finishing of the raster milled surface. The material effect on surface roughness decreases with the increasing of feed rate. The precipitates in the machining of aluminum alloy 6061 result in the generation of imperfection on the raster milled surface. The machining of aluminum bronze has the greatest influence on surface roughness among the three materials being cut, which is due to its high elastic recovery rate and hardness.