Thermal Affected Zone Evolution and Material Removal Rate Regulation in CFRP Laser Cutting: An Experimental Study on Pulse Width Parameters

This study systematically investigates the influence of laser pulse duration on cutting efficiency, heat-affected zone (HAZ) formation, and mechanical integrity in CFRP laser cutting. Three distinct pulse-width lasers—picosecond, nanosecond, and quasi-continuous-wave (QCW)—are compared. Results show that pulse duration governs material removal mechanisms and HAZ extent: nanosecond laser achieves the smallest HAZ and minimal porosity; picosecond laser exhibits limited thermal accumulation due to low average power; QCW laser induces the largest HAZ (11.6 times that of nanosecond laser) and significant porosity. Cutting efficiency scales inversely with pulse width, with single-hole processing times of 480.4 s for picosecond laser-cut, 76.8 s for nanosecond laser-cut, and 4.028 s for QCW laser-cut, reflecting a transition from thermal ablation to mechanical spallation. Mechanical testing reveals that while tensile and flexural strengths vary by < 5% across laser types, damage morphology and failure modes differ significantly. In situ digital image correlation (DIC) and 3D CT imaging show that longitudinal plies fail via fiber pull-out, whereas transverse plies fail via interfacial debonding. QCW-laser-cut specimens exhibit more uniform strain distribution and higher damage tolerance. An optimized process parameter is proposed: nanosecond laser cutting at 200 W and 20 kHz achieves a HAZ of less than 50 µm and a cutting time of less than 80 s, offering the best balance between efficiency and quality.