A general on-machine non-contact calibration method for milling cutter runout

Cutter runout is a very common phenomenon in the actual milling process. It always becomes an interference factor, which will cause the distortion of milling force waveform, the variation of milling stability pattern, and the deterioration of machined surface roughness. The paper presents a general on-machine non-contact calibration method for cutter runout, and systematically expounds its causes, types, and identification method. Firstly, a general geometric parameter representation model for the integral and inserted milling cutters is established. Then, three kinds of runout status, including the cutter rotation axis eccentricity, geometric axis eccentricity, and bottom edge eccentricity, are quantitatively described by seven independent parameters. Moreover, by using the eddy current sensor to non-contact measure the target length of the tooth with cutter running on the spindle, the changes of the actual cutting radius at different axial heights on different teeth are obtained. Combined with the numerical optimization method, the separated calibration of the above three types of cutter runout parameters are realized. Finally, a series of verification experiments are carried out for the integral and inserted milling cutters. Both the analysis results of the machined surface morphology and the comparison with the indirect measurement method show that the proposed method is accurate for calibrating the runout parameters. As an on-machine non-contact calibration method, it has a good applicability when dealing with different kinds of cutter, types of runout, and spindle speeds.