Dynamic characterization of tool-chip contact area and chip form

Abstract

This study proposes an experimental data processing technique integrating micro-CT scanning and high-speed imaging to clarify the causes of irregular chip shape and its relationship with the tool-chip contact area. The technique includes extending the chip formation definition to include the torsional zone, analyzing irregular helical chips geometrically, and reconstructing the spatial posture of the chip. The study shows that chip form irregularities result from the clamping effect of the tool and workpiece on the free end of the chip, which changes the chip deformation in the torsional zone. No significant correlation is found between this irregularity and the tool-chip contact area. The angle between the tool-chip separation line and the chip flow velocity remains relatively stable. Microscopic morphological analysis reveals that the abrupt change of chip shape is caused by a sudden change in the chip-workpiece friction direction, which triggers plastic accumulation and significantly affects chip formation in the torsional zone, causing the chip to detach from the clamping effect and undergo severe deformation. The study concludes that the clamping effect plays a critical role in chip formation and provides an estimation of the geometric features of the tool-chip contact area, offering valuable data for dynamic cutting process modeling and process optimization.