Morphological Characteristics and Evaluation Indicators of CFRP Drilling Burrs Based on Polar Coordinate Mapping

doi:10.3901/JME.2025.07.167

Abstract

Abstract: Drilling is a common procedure in machining CFRP parts. The connection strength, assembly accuracy, and internal stress are directly influenced by the machining quality, which is crucial to the properties of the whole structure. However, due to the characteristic inhomogeneity and anisotropy of CFRP, fiber breakage and material removal during drilling is stochastic, which leads to prevalent burr defects around the holes and affects the processing quality. Thus, it is significant to recognize, evaluate, and control the burr defects of CFRP holes. In this study, CFRP hole image processing method based on polar mapping is proposed, where the effects of image panning, rotation, and zoom are excluded with the original features of the burr being retained so that the convenience of defect identification and evaluation has been improved. Then, a parametric evaluation method of the hole contour curve based on pseudo-spectrum is established, and the burr phenomenon was quantified by the pseudo-spectrum of the tangential vector direction angle function of the hole contour curve in the natural coordinate system. Finally, the proposed theory and method are verified by experiments. The results show that in the pseudo-spectrum of the contour curve, the peak frequency can reflect the size of the burr, the total power can reflect the overall number of burrs, the fiber cutting angle will affect the shape of the burrs during drilling, and the appropriate increase of the spindle speed and the reduction of the feed rate can effectively reduce the burr defects. The CFRP hole image processing method and burr evaluation index proposed in this study have considerable accuracy and effectiveness, and are expected to be applied to the online monitoring of CFRP component drilling process and other fields, so as to improve the reliability and convenience of hole quality analysis.

Key words: carbon fibre-reinforced polymer, burr, morphology, drilling, image processing

CLC Number:

TG156

LIANG Siyu, LIU Guangjun, CHEN Tao, HELIAN Bobo, WANG Yunfei. Morphological Characteristics and Evaluation Indicators of CFRP Drilling Burrs Based on Polar Coordinate Mapping[J]. Journal of Mechanical Engineering, 2025, 61(7): 167-180.

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