Analysis of drilled holes on Carbon Fibre material with X-ray Computed Tomography

This paper presents the methodology used to investigate numerous drilled holes that have been produced on Carbon Fibre Reinforced Polymers (CFRP) under different parameters. Due to the nature of CFRP, machining processes may cause severe damage such as delamination, which will affect the service life of the parts. The delicate matrix orientation of CFRP determines their properties. These delaminated regions are often inaccessible because they are formed throughout the distance of the machined area and they are usually studied with the help of destructive methods that may destroy some of the investigated defects. X-ray Computed Tomography (CT) can provide precise data of such defects non-destructively. The utilisation of CT allows the identification and examination of all defects and can analyse them automatically, consequently reducing human error. The developed method allows optimum dimensional measurements to be obtained with an automated analysis of image processing. The results of the analysis investigate the inner faults that are common with drilling in CFRP, the deviation of the radius and circularity throughout the hole. In addition, the distance between the actual and intended centre is calculated. The proposed method with the application of CT provides significant, previously unreachable data that can benefit the selection of a machining process.