In recent years, nanosecond and picosecond lasers have demonstrated remarkable capabilities in the laser processing of metals with minimal thermal effects, high efficiency, and precision [1]. However, despite numerous advancements in ablation efficiency optimization [2-9], optimizing the cutting speed of thin sheets remains a challenge, even though recent theoretical progress has been reported [10]. Maximizing laser cutting speed is crucial for industrial applications, as it directly impacts manufacturing efficiency, energy consumption, and overall production costs.
This study aims to investigate the key factors influencing the laser cutting speed of thin metal sheets using nanosecond and picosecond pulses, including laser parameters and process optimization strategies. By systematically analyzing the effects of peak laser fluence controlled by focal positioning, we seek to establish optimal conditions for enhancing cutting speed. Additionally, a comparative analysis was conducted to determine the advantages and disadvantages of nanosecond versus picosecond lasers in cutting thin stainless-steel sheets. Laser irradiation with a central wavelength of 1064 nm, controllable pulse durations of 4.5 ns or 13 ps, and a repetition rate of 400 kHz was used in the experiments. We determined that the maximum cutting speeds were 28 mm/s for nanosecond pulses at an average laser power of 38 W and 14 mm/s for picosecond pulses at an average laser power of 44 W for stainless steel sheets with a thickness of 0.3 mm at certain optimal fluence values using a slightly defocused Gaussian beam. The beam size optimization theoretical approach was adopted from [10] to explain the experimental data. These results will be valuable for industries requiring high-precision microfabrication, such as electronics, automotive, and medical device manufacturing, where speed and accuracy are most critical.