In the process of helical milling of carbon fiber reinforced polymer (CFRP)

defects such as delamination

tearing and burr at the hole making outlet are caused by excessive axial force produced by the end edge of the tool. In order to reduce the axial force in the helical milling of CFRP

the relationship between the tool end backlash angle and the undeformed chip was analyzed based on the kinematic principle

thus a method was proposed to make the center area with low cutting line speed not participate in the cutting. Furthermore

the condition that the tool center does not participate in cutting was deduced

and the shape of undeformed chip under different combination of end backlash angle and lead is simulated. Finally

the helical milling test was carried out on CFRP. The results show that by increasing the tool end backlash angle and reducing the lead

the center area of the end edge in the helical milling can do not participate in the cutting

so as to reduce the axial force in the helical milling of CFRP effectively.