Surface Variation Reduction for Face Milling Based on High-Definition Metrology

This paper develops a face milling planning method to reduce surface height variation based on the high definition metrology (HDM). HDM provides high-lateral resolution data over an area up to 300×300 mm². The measurement results on production engine head surfaces reveal a strong correlation between the surface height and the effective material removal rate (eMRR) along the cutting path. Such a correlation can be explained by a cutting force model which verifies that the surface variation is attributed to the axial cutting force variations, and the axial force is proportional to the eMRR. This paper proposes a machining algorithm that minimizes eMRR to reduce the cutting force variation by altering the feed rate and cutter path, thereby reducing the surface height variation. The varying feed approach can eliminate one surface pattern in the case study without significantly changing the cycle time. The optimized cutter path results in 25% reduction in zone flatness on the other surface pattern. This improvement demonstrates the potential of the eMRR based approach in attaining cost-effective high-precision machining. The method may also be extended to a wide range of face milling applications.