Experiments on femtosecond laser micromachining of grooves in spring steel (65Mn) were performed with Ti:Sapphire
laser pulses of 5Ofs duration. The relationships between the dimensions of the grooves and the cutting parameters were
analyzed. A logarithmic dependence of the groove depth on laser fluence was observed with two regimes characterized
by different ablation rates and different thresholds. The groove depth was found to be inversely proportional to cutting
speed and proportional to the number of passes. A depth limit was found with decreasing cutting speed or increasing
number of passes. Cutting speed and the numbers of passes have little effect on the width of grooves. The
morphological of period surface structures and unevenness depth was observed using scanning electron microscope.
The result in the paper provides instructive guide for future research on three-dimension microstructures.
Laser forming of sheet is a forming technology of sheet without a die that the sheet is deformed by internal thermal stress induced by partially irradiation of a laser beam. In this paper, the bending behavior of common stainless steel 1Cr18Ni9Ti sheet is studied after being irradiated by straight line with a Nd:YAG pulse laser beam. The aim of the investigation is to find out the relationship of the bending angles with the pulse parameters of the laser. The experimental results show that higher width of pulse is advantageous to increase the bending angles if the total outer power and the rate of the pulse are constant. The bending angle increases as the rate of the pulse increase and begins to decrease at a certain processing parameters. And the bending angle firstly increases with the pulse energy increasing and begins to decrease at a certain processing parameters, as there is a certain pulse energy parameter resulting in a maximum bending angle for a certain material and processing parameters. The pulse energy is the most important factor influences the bending angles of pulse laser forming in the pulse parameters. By qualitative analysis of experimental result, the conclusion obtained may provide basis for theoretical investigation and possible industrial application of laser bending process in the future.
In this paper, the experiments of cutting titanium alloy sheet with Nd:YAG pulsed laser were carried out and the effects of the type of shielding gases, gas pressure and laser parameters on kerf width, surface quality and metamorphic layer thickness were studied. The results showed that compressed air is suitable for laser cutting of titanium alloy, the Argon gas does better, while Oxygen gas has undesirable effects; the metamorphic layer is thicker with compressed air as assisted gas in comparison to that with Argon gas; the kerf width increases as the power density, pulse frequency and pulse width increase; higher cutting speed can be applied and the cutting quality is improved when the pulse frequency is increased.