Development of NCLR's 1-kW XeCl laser

et al. 2005

Appl. Phys. A

After the development of a novel XeCl excimer laser with a nearly diffraction-limited beam and 175 ns pulse length, research was done on different industrial applications of this laser. Hole drilling, one of these applications, was studied extensively. A better understanding of the drilling process is necessary to optimise the drilling efficiency and to control the quality of the holes. A shadowgraphic imaging technique was used for studying the removal of material from the hole and the absorption of the laser beam by this removed material. Images were made at successive times both during and after the laser pulse.In drilling of thin foils, it was shown that the material was ejected mainly after the laser pulse. A comparison of different materials showed that the drilling process should be optimised for each material independently. Furthermore, the plume was found to be not fully transparent for processing materials with a strong absorption line at or near the laser wavelength. The correlation between material and drilling speed suggests improved energy transfer and improved melt ejection for the materials with this absorption.

Section: Introductionmentioning

confidence: 99%

Shadowgraphic imaging of material removal during laser drilling with a long pulse excimer laser

Schoonderbeek

et al. 2005

Appl. Phys. A

“…A novel 1 kW XeCl excimer laser ͑ϭ308 nm͒ with a pulse energy of 1 J and a repetition rate of 1000 Hz has been developed by Nederlands Centrum voor Laser Research. 3 A unique feature of this excimer laser is its excellent beam quality, 4 which is nearly diffraction limited. This excellent beam quality originates from the long optical pulse length and enables usage of the entire beam instead of using mask projection techniques.…”

Section: Introductionmentioning

confidence: 99%

The influence of the pulse length on the drilling of metals with an excimer laser

Schoonderbeek

Journal of Laser Applications

et al. 2004

Self Cite

Articles you may be interested inStudy of laser beam propagation in microholes and the effect on femtosecond laser micromachining Laser parameters, which significantly influence laser-material interaction processes, are the wavelength, the energy, and the power density. Additionally, there are parameters, like the pulse length, which also strongly influence processing speed and quality. Studies where different types of lasers have been used indicate that long pulses are beneficial for processing speed. However, when different types of laser systems are used to study the effect of the pulse length, a direct comparison of the results is difficult because the use of different lasers involves a simultaneous variation of other parameters ͑e.g., wavelength͒ as well. In this study a technique of pulse length variation is used in which the pulse length is the only varied parameter and thus enables the desired direct comparison. Pulses with different lengths are sliced out of pulses of a long pulse XeCl excimer laser, keeping all other laser parameters unchanged. Results are shown of hole drilling experiments in 125 m nickel, 25 m aluminum, and 125 m aluminum foil with pulse lengths between 9 and 150 ns. The influence of the pulse length on material processing is discussed in connection with energy and power of the pulses. The experiments show that both for pulses with the same energy and the same power long pulses remove more material than short pulses and, moreover, long pulses can yield higher quality of the drilled holes.

“…Therefore the average power of this laser is 1 kW. 1 Special are the long optical pulse length of 150 to 200 ns and the excellent beam quality (nearly diffraction limited). 2 The latter enables focussing of the entire beam without using mask projection techniques.…”

Section: Introductionmentioning

confidence: 99%

High-speed drilling of metals with a long-pulse XeCl excimer laser

Schoonderbeek¹,

et al. 2002

SPIE Proceedings

Studies of the influence of pulse length on material processing with different lasers have shown that a long pulse is beneficial for processing speed. In this paper a technique of pulse length variation is used in which the pulse length is the only varied parameter. Pulses between 5 and 150 ns length are sliced out of the 175 ns pulse of a long pulse excimer laser. The beam quality for each sliced pulse length is similar. In this paper the results are shown of hole drilling experiments in 125 µm aluminium foil with pulses of 10 and 100 ns length. The influence of the pulse length on material processing is discussed in relationship with equal energy and equal power density of the pulses. This study shows that in both cases long pulses remove more material than short pulses.