The effects of support plate thickness on the drilling machinability of CFRP

When carbon fiber reinforced plastics (CFRP) are drilled, delamination damage occurs at the hole entry and exit. An important method to reduce delamination at the hole exit is using a support plate. Therefore, sustainable drilling of CFRP to reduce the delamination damage is promising for modern industries. In this study, the effect of drilling CFRP composite plates using support plates of different thicknesses on thrust force, delamination, and borehole surface quality was experimentally investigated. The results showed that the thrust force increased as the support plate thickness increased at low spindle speed, but the support plate thickness did not significantly affect the thrust force at high spindle speed. While severe delamination damage occurred at the hole exit in the tests without the use of support, delamination damage was significantly reduced in the case of using a support plate. On the other hand, the severity of the damages decreased as the support plate thickness increased, especially unless very high feed rates were chosen. Consequently, the thickness of the support plate considerably influences the damage formation and severeness of the damages is significantly reduced when a support plate with sufficient thickness is used.