A critical review of the drilling of CFRP composites: Burr formation, characterisation and challenges

Burr is one of the main macro-geometrical types of damage concerning machined features of carbon fibre reinforced polymer (CFRP) composites. Even if it does usually not weaken the strength of composite materials, it is recommended to be removed. The deburring process often leads to significantly increased operation time and cost. In both the industry and academia, digital processing of optically captured images is the most common evaluation method for burr-characterisation. Nevertheless, there is no agreement on the measures and techniques of burr-evaluation in CFRPs. Recent key papers on burr formation, measurement and evaluation in CFRPs are reviewed in an attempt to standardise and classify burr characterisation related expertise. In this paper, burr formation mechanisms, burr measurement methods and burr parameters are critically reviewed, compared and discussed. The main advantages and disadvantages of burr measures are highlighted and their possible future applications and prospects are also considered. Furthermore, burr measures reviewed are compared and discussed based on an experimental data set. •Burr formation mechanisms are reviewed and discussed in CFRPs.•Challenges and solutions in digital image processing of burrs are introduced.•Burr-parameters are categorised, summarised and evaluated.•Burr-parameters are compared based on an experimental data set.