微小孔螺旋磨削加工磨粒切削特性研究

The helical grinding process is an effective method for fabricating micro-holes in difficult-to-machine materials. However, there is a scarcity of research on undeformed chip model that accounts for the weak rigidity of the tool. To address these issues, a kinematic analysis of helical grinding is carried out, establishing a model for undeformed chip thickness/height and cross-sectional area on the side edge, and analyzing the impact of tool deflection on undeformed chips. Employing image recognition techniques, the variation law of effective abrasive grains count on the bottom edge is obtained, defining the effective nominal number of cutting edges and establishing a model for the undeformed chip thickness of a single grain considering tool deflection. Based on these models, the cutting characteristics of abrasive grains at different positions on the tool are studied. It is found that there are pure bottom edge cutting grits, pure side edge cutting grits, and mixed cutting grits. The distribution range of pure bottom edge cutting grits, D_p, is defined; when the tool diameter is two-thirds or less of the target hole diameter, D_p equals zero, significantly reducing bottom edge chip bonding and optimizing grit cutting performance. Finally, micro-hole helical grinding experiments are conducted on high-volume SiC_p/Al and quenched TiC_p/Fe. The research findings provide theoretical guidance for cutting parameter selection and tool design in micro-hole helical grinding.