Investigation of Hole Quality on Drilling Carbon Composites with a ‘One Shot’ Drill Bit

Successful drilling of aerospace structures is very dependent on the quality of the holes produced. This paper investigates the relationship between drilling parameters and the quality of holes when drilling carbon composite using a ‘one shot’ drill. For the aerospace industry, where hole tolerances are very tight, an understanding of hole quality parameters is essential.

In this research, special attention is given to the effect of tool age and reaming time on the size of the hole, break outs and surface finish. The drilling process is divided into stages and the relation between the stages and quality of holes investigated. The findings from this paper can be used to minimise drilling defects corresponding to the age of the drill bit.