Dedicated drill design for reduction in burr and delamination during the drilling of composite materials

Abstract

In the drilling of composite materials such as carbon fiber reinforced plastic, burrs and delamination occur during machining. This study proposed a design of a drill tool with a shape that suppresses burrs and delamination during the drilling of composite materials. The tool shape (tip, groove, land, etc.) is determined, and a nick shape that cuts off chips and reduces heat generation is adopted. A finite element analysis and an experimental evaluation involving 4600 holes were conducted. The maximum errors in the hole diameter and roundness were 15 μm and 0.016, respectively. Further, the maximum burr height was observed to be 80 μm or less, and delamination was not observed in the experiment.