Dynamic error detection and error source analysis for ultra-precision flycutting machine tools

摘要

The ultra-precision single point diamond flycutting is an effective way for finishing potassium dihydrogen phosphate (KDP) crystals. However, the dynamic performance and motion precision of the machine tool would introduce the errors and have an adverse effect on the surface quality of elements. In this study, a significant method is presented to trace error sources by combining monitoring the rotary errors and analyzing the machined surface. On the one hand, forward recursion method is adopted. Based on the online measuring platform, the radial error, axial error and inclination error of spindle rotation can be obtained. Through the Fourier transform algorithm, the frequency information in each direction is known. Furthermore, the waviness along the feed direction is identified, which is determined by the rotation fluctuation. On the other hand, a novel method for errors tracing is presented by a reverse thinking mode based on the surface topography. The wavelet analysis is carried out along the cutting direction, and the obvious waviness appears in the 4th layer, of which the dominant frequency is 594Hz. Through the knocking test for the spindle system, the waviness error along the cutting direction is determined as the modal vibration of the spindle system.