非共轴螺旋后刀面微钻的五轴联动刃磨方法及其钻削性能研究

Drill point geometry is a most significant element for drilling performance and micro-hole quality. Non-coaxial helical drill point is characterized by a continuous helical flank surface, and its special geometry contributes to a better grinding efficiency and a superior drilling performance. The position equation of generating line of helical surface is obtained, and the mathematical model of contact line between helical drill flank and wheel is proposed. According to the motion of 6-axis CNC tool grinder, a 5-axis coordinated grinding method of helical drill flank is presented. Based on the relative motion of drill flute and wheel, a CNC grinding process of micro-drill flute is proposed. Then this grinding method is validated by fabricating the helical micro-drill. For the planar, conical and helical micro-drills with the same geometry parameters, the drilling experiments on austenitic stainless steel are conducted, and the drilling force and tool wear are measured and analyzed. The results show that the thrust force and flank wear of helical, conical drill point are smaller than that of planar drill point, and the chisel edge wear of helical drill point is smaller than that of planar, conical drill point. It is confirmed that the proposed grinding method is effective to fabricate the helical micro-drill with good drilling performance.