Prediction of surface topography for the five-axis bull-nose end milling of directional plexiglass considering tool runout and dynamic displacement

Five-axis CNC bull-nose milling is potentially used in the machining of directional plexiglass due to its high machining efficiency and suitability for machining curved surfaces. During the milling process, factors such as tool geometry, feed rate, tool runout, and vibration displacement can directly affect the surface topography of the machined parts, which in turn affects the serviceability of the parts. To investigate the generation mechanism of surface topography and select the machining parameters more rationally, a surface topography prediction model for the five-axis bull-nose end milling considering tool runout and dynamic displacement is established. Firstly, a five-axis bull-nose end milling cutting force calculation model considering a multi-regenerative effect is established. Further, the milling dynamics equation considering multi-modes is set up, and the tool vibration displacement is calculated by the Euler method. Then, to accurately predict the surface topography, the gained vibration displacements are integrated into discrete positions of the cutter edges considering tool runout, and milling surface topography is predicted by the Z-map method. Finally, a series of predicted simulation examples and milling experiments are conducted, and the effect of tool runout, vibration displacement, and machining parameters on surface topography is analyzed. The results show that the simulation examples are in good agreement with the milling experiments.