| Abstract [eng] |
Ceramics are a popular material used in many fields: medicine, the automotive industry, the electronics industry, and others. Ceramic processing commonly involves mechanical processes such as milling, drilling, and cutting. Unfortunately, mechanical processing has several drawbacks: tool wear, expensive tools required for material processing, and limited processing accuracy. Laser processing has been integrated into industrial processes for some time due to its ability to process various materials, including ceramics, while avoiding the drawbacks of mechanical processing. Femtosecond laser processing is a suitable technology for processing hard and brittle materials, such as aluminum oxide ceramics (alumina), ensuring high processing quality. However, the processing speed of femtosecond lasers is still behind other methods, limiting the technology's full integration into industrial applications. One way to increase the speed is to use a burst mode, where the femtosecond laser fires pulse trains at MHz or GHz frequencies. The aim of this study was to evaluate the impact of MHz/GHz burst modes on the ablation efficiency and speed of alumina ceramics. The study was conducted by varying the laser power, pulse overlap percentage, and burst modes. The results showed that GHz bursts are the most suitable for aluminum oxide processing. Due to the high repetition rate, the initial low-energy pulses in the burst heat the material and lower its damage threshold. When the damage threshold decreases to the energy of a single pulse in the burst, effective material ablation occurs. Thus, using GHz bursts, the ablation rate was increased from 6.39 mm³/min to 10.38 mm³/min, and the ablation efficiency was increased from 0.375 mm³/min*W to 0.877 mm³/min*W. |
