Influence of processing parameters on micro-perforated with ultrashort pulses

摘要

In this work, ultra short laser pulses (110 fs, 1 kHz; up to 1.1 mJ/pulse) were used for micromachining steel samples. Processing with ultra-short laser pulses allowed achieving circular micro holes, with precise measurements and no significant chemical or mechanical disruption of adjacent areas. The helical drilling optics system by TGSW-Stuttgart is used to generate the holes. This system allowed producing high aspect ratio and complex structures with variable diameter throughout the hole. To did this, up to three processing parameters may be changed at the same time (beam rotation speed, angle and of the beam) and during the processing. We study the influence of the laser wavelength on the holes geometry. Specific optics for both the fundamental (λ = 790nm) and second harmonic wavelength (λ = 395nm) were used to microstructure steel, comparing the results. From the study we can conclude that there aren´t advantage when using the second harmonic. Weaknesses in the experimental device had been detected, to find the solution at this topics allow precisely evaluate the influence of wavelength