Investigation of underwater laser drilling for brittle substrates

Laser Beam Machining, Laser Beam Hybrid Machining, and Micro-channels Applications and Fabrication Techniques

“…All such factual truths can be eliminated/improved by incorporating a water environment. The authors of [184] experimentally proved that during the array-hole drilling the hole-distance of even 1-2 mm can be achieved for brittle materials with crack free edges by using a 1 mm water layer above the work surface. Lu et al [11] investigated the mechanism behind the quality improvements by underwater laser drilling of various metal plates including copper, aluminum, iron, stainless steel with varying thickness.…”

Micro-dimple array fabricated on surface of Ti6Al4V with a masked laser ablation method in air and water

“…Zhu [25] and Dupont [26] confirmed that the shock pressure may highly enhance the ablation rate, but it has also been reported by Iwatani [27] that it produces mechanical stress that may cause substrate cracking in the heat affected zone. Secondly, most of the molten material ejection will be cooled down, dissolved, and consequently carried away by the water rather than sticking on the sample surface around the micro-dimple periphery as in air, because the heat conductivity of water is higher than air [28]. Thirdly, microvoid structures at the bottom are only generated in the water condition as shown in Fig.…”

An investigation of energy loss mechanisms in water-jet assisted underwater laser cutting process using an analytical model

“…Laser drilling, cutting, micromachining of brittle materials like glass, silicon wafer, silicon carbide, alumina, etc. carried out in water environment also reportedly have higher processing rates, efficient debris removal, better surface morphology and less thermal damages compared to that in air [3][4][5][6]. Besides its several advantages, this process has certain issues, like absorption of laser beam in water and scattering of laser light from the processing zone.…”