Monitoring of in-process force coefficients and tool wear

Mechanistic modeling of the milling forces is described by a set of cutting and edge force coefficients that characterize the shearing and ploughing actions of the metal removal process. The force coefficients are traditionally calibrated under a series of dedicated milling experiments. However, due to the force coefficients’ process-dependency, such an approach can become cumbersome if the machining conditions deviate from those of the milling experiments. In this paper, a method for monitoring the in-process force coefficients is proposed for toolpaths that exhibit varying radial immersions or feed rates. The proposed methodology was experimentally validated, and it is demonstrated that the edge force coefficients can be used to estimate the tool's flank wear. In the absence of a force dynamometer, force coefficients as estimated under spindle current measurements were evaluated and also shown to be a viable solution for tool wear monitoring.