Chip volume and cutting force calculations in 5-axis CNC machining of free-form surfaces using flat-end mills

This paper presents two new methods and associated algorithms for numerically modeling chip geometry and calculating cutting force for parts with free-form surface during 5-axis CNC machining using a flat-end mill. Extending the computational geometry-based Alpha shape method that can only predict cutting chip geometry, a parallel slice local volume modeling approach has been added to predict cutting forces as well. To demonstrate the validity and capability of these new methods, simulation of the cutting and chip forming process of 5-axis CNC machining on a free-form surface has been carried out. Physical validation experiment in controlled conditions has been carried out on a 3-axis micro CNC machine with the two cutter rotation angles set to be zero. The predicted and measured cutting forces are in reasonably good agreement both in trend and magnitude. The presented chip volume and cutting force method can be used to perform cutting force estimation for generating optimal tool path and orientation during 5-axis milling. The method requires longer computational time than traditional analytical methods, but it supports the ultimate goal of chip volume modeling and calculation—accurate dynamics cutting force prediction.