Development of a step drill for minimization of delamination and uncut in drilling carbon fiber reinforced plastics (CFRP)

摘要

A step drill is developed to minimize delamination and uncut fiber in machining carbon fiber reinforced plastics (CFRP), which consists of two parts, a core part and a step part. The core part is designed to minimize the thrust force by controlling core diameter. The step part is designed to remove the delamination generated by core part without 2nd delamination, which consists of step angle. The effect of feed rate and spindle speed on the performance of drilling also investigated. To remove the uncut fibers properly, the higher rake angle of step part is applied. By measurement of thrust force, it is found that the delamination can be reduce when smaller thrust force is generated. As a result, a step drill is designed for less generation of delamination and uncut fiber for drilling T700 3K CFRP.