Correlation between different cutting conditions,surface roughness and dimensional accuracy when ball end micro milling material measures with freeform surfaces

Abstract

Material measures are used to calibrate topography measuring instruments. Micro-milling is a suitable process for the manufacturing of areal material measures in particular of material measures featuring freeform surfaces. To improve their surface quality and to minimize their deviations from the target geometry, the cutting parameters feed per tooth respectively feed rate and spindle speed are examined in this study. Dependent on the varied parameters the deviation of the manufactured topography from its target geometry, the deviation to the nominal surface texture parameters and the short-wavelength roughness parameters are evaluated. Two different ball end micro-mills and two different target geometries are chosen to investigate whether the observed dependence on the varied parameters are valid independent from the tool and the target geometry. It is illustrated that the feed rate has a large influence on the dimensional accuracy: the dynamic properties of the axes are identified as reason for the decreasing amplitude with increasing feed rate. The spindle speed only influences the short wavelength roughness and has a minor influence on the surface quality.