High throughput and low surface roughness laser layer-by-layer milling using nanosecond (ns), picosecond (ps), and hybrid ns-ps pulses: A comparative study

Abstract

This paper reports a comparative study of ablation efficiency and quality using conventional nanosecond (ns), conventional picosecond (ps), and novel hybrid ns-ps irradiation modes. The aluminum alloy was machined using a laser with the traditional ns and ps pulses at various repetition rates. Also, the hybrid ns-ps irradiation regime was applied for the first time in laser milling. Laser fluence was optimized to ensure the efficient utilization of laser pulse energy for the maximal rate of material removal. For hybrid ns-ps, conventional ns, and conventional ps pulse processing regimes, direct comparisons of surface roughness of laser-milled cavities as well comparisons of ablation efficiencies with literature values were conducted. Experimental results coincided well with the theory of efficient ablation. The layer-by-layer efficient laser milling technique was applied for the fabrication of aluminum molds designed for LED diffusers.