Relationships of tool wear characteristics to cutting mechanics, chip formation, and surface quality in ultra-precision fly cutting

Although the occurrence of tool wear can affect cutting forces, cutting chip morphologies, and machined surface quality in ultra-precision fly cutting (UPFC), there has been no research in this area due to the complex cutting mechanism of UPFC. The theoretical and experimental research described in this paper was therefore conducted to explore tool wear characteristics in UPFC and their relationship to cutting forces, cutting chip morphologies, and machined surface quality. Results from the study reveal that tool wear characteristics in UPFC include cutting edge fractures, workpiece material welding, wear land formation, sub-wear land formation, and micro-grooves. The cutting edge fractures lead to the formation of ridges on both the cutting chips and machined surface; the material welding increases the thrust force, crushes cutting chips, and deteriorates the machined surface quality; and the formation of wear land on the cutting edge makes the machined surface burred and fuzzy, and the micro-grooves leave some traces on the machined surface. By analyzing the captured cutting force, it is found that the progress of tool wear in UPFC can increase the cutting force and its power spectral density at the natural frequency of the dynamometer. Findings from the research provide rich insight into the relationships of tool wear characteristics to cutting forces, chip formation, and machined surface quality in intermittent cutting processes.