A review on laser drilling optimization technique: parameters, methods, and physical-field assistance

Laser processing has emerged as a pivotal technique for micro-hole fabrication owing to its exceptional efficiency and absence of tool wear. Nevertheless, certain imperfections persist in laser drilling. Consequently, this study presents a comprehensive analysis of the impact of laser processing parameters, methods, and physical field-assisted techniques on the quality and efficiency of laser drilling based on the characteristics desired for micro-holes. The findings reveal that selecting an appropriate laser wavelength and pulse width, coupled with meticulous adjustments to laser power, repetition frequency, and defocusing amount can enhance either processing efficiency or micro-holes quality; however, optimizing both aspects simultaneously remains challenging. By refining scanning strategies and implementing pulsed joint secondary repair approaches, heat accumulation is minimized while micro-holes quality is optimized; nevertheless, ensuring high processing efficiency poses difficulties. Ultrasonic assisted laser drilling enhances processing efficiency by facilitating the expulsion of molten materials, while magnetic field-assisted laser drilling improves processing efficiency by mitigating the attenuation of the laser caused by plasma clouds. Both techniques contribute to enhancing the quality of hole walls through their stirring effect. Water-based ultrasonic/magnetic field-assisted laser perforation combines heat dissipation and secondary flushing effects with ultrasonic/magnetic field assistance, resulting in superior micro-hole formation. Magnetic field-ultrasonic assisted laser perforation synergistically combines both effects. Furthermore, this study distinguishes between the promoting and inhibiting effects of rotating and static magnetic fields on molten metal flow, elucidating the impact of ultrasound and magnetic fields on molten metal from a melt dynamics perspective. Finally, we summarize the influence of each optimization method on micro-hole quality characteristics and processing efficiency while providing insights into future development trends.