Comparison of conventional drilling and orbital drilling in machining carbon fibre reinforced plastics (CFRP)

Drilling of highly abrasive carbon fibre reinforced plastics for the aerospace industry requires a machining process with excellent bore quality, sufficient tool lifetime and simultaneously short cycle time. This paper presents a comparison between conventional and orbital drilling of heavy-to-cut unidirectional CFRP material with diamond coated tools. The material contains high fibre content and a polished-like surface at bore exit. Focus of the process comparison is on introduced workpiece damages, tool wear, bore diameter variances as well as cycle times. Three dimensional bore exit microscopy, micrographs and expansion tests with conical pin are used to evaluate the workpiece integrity.