Experimental Study on Drilling High Aspect Ratio Micro-holes in CFRP Using Laser with Variable Angles of Incidence

doi:10.3901/JME.2025.21.427

Abstract

Abstract: Carbon fiber reinforced plastic (CFRP) composites possess exceptional properties such as high specific stiffness and strength, superior thermal stability, and excellent corrosion resistance, making them widely used in fields such as aerospace, medicine, and defense. However, the inherent differences in material characteristics between the fibers and the resin matrix in CFRP present significant challenges for conventional methods to effectively process high aspect ratio micro-holes. To address this issue, an ultrafast laser processing system with adjustable angles of incidence (AOI) is designed and constructed to investigate its capability in processing high aspect ratio micro-holes in CFRP. A comprehensive analysis is conducted to examine the influence of laser pulse energy, scanning speed, and AOI on the machining quality of CFRP micro-holes with a diameter of 200 μm and an aspect ratio of 10:1. The results indicate that laser pulse energy and scanning speed have a significant impact on the size of the heat-affected zone (HAZ) at the micro-hole entrance and exit, while AOI substantially affects the taper of the micro-holes. A spiral scanning strategy with variable AOI effectively addresses the issue of uneven energy distribution caused by changes in focal depth when using a fixed AOI, significantly reducing the taper of the micro-holes, and even enabling the fabrication of negative taper micro-holes. Furthermore, the implementation of appropriate trimming and cleaning strategies effectively reduces sidewall roughness, achieving a minimum surface roughness (Ra) of less than 0.8 μm. Finally, the effectiveness of optimized process parameters is validated by machining a 2×3 micro-hole array, demonstrating the tremendous potential of variable AOI laser processing in the fabrication of high aspect ratio CFRP micro-holes.

Key words: laser processing, CFRP, micro-holes, variable angles-of-incidence

CLC Number:

TN249

MA Yao, WANG Yuqi, XU Wenjun, CUI Jiarong, LI Jun, LUO Tao, ZHOU Wei. Experimental Study on Drilling High Aspect Ratio Micro-holes in CFRP Using Laser with Variable Angles of Incidence[J]. Journal of Mechanical Engineering, 2025, 61(21): 427-436.

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