Laser drilling is a laser processing technology that punches holes through a pulsed heat source with high power density and short stay (lower than laser cutting). Aperture formation can be achieved by single pulse or multiple pulses.
In the punching process, first use the punching mode to prepare small holes of sufficient size, so that the subsequent cutting process starts from here. The drilling or penetration process requires a repeatable pulsed laser beam with high peak power, and at the same time, it is realized with a high air pressure. After the workpiece is penetrated, the laser beam is cut by reducing the peak power or even changing to a pulseless mode.
Solid-state lasers have shorter wavelengths and can achieve high-intensity pulse output, so they are more suitable for laser drilling, such as Nd:YAG lasers, Nd:glass lasers and Nd:ruby lasers.
CO2 lasers are often used to open pores in non-metallic materials such as ceramics, composites, plastics or rubber. Laser drilling of metal materials requires a pulsed laser, and the beam focusing power density should be above 10^5 W/mm^2 (6.5 W/in.^2 × 10^7 W/in.^2).
Focusing of the laser beam
In laser drilling mode, a short focal length lens is required to focus the high peak power beam of the pulsed laser onto a spot on the order of 0.6 mm in diameter to achieve the power density level required for drilling.
Low divergence of the laser beam can be achieved by specific laser resonators. The beam diameter can be controlled by changing the aperture of the focusing device. Therefore, the aperture can be used to increase the energy density of the focused beam and improve the intensity distribution of the beam.
Advantages of laser drilling technology
Laser drilling has most of the advantages of laser cutting. It only needs to make the beam and the surface of the material form a certain angle to realize the intake and punching of the laser beam, which effectively avoids the occurrence of impact and fragmentation caused by structural interference during mechanical processing.
Other advantages of laser drilling
1. Short opening time
2. Strong automation adaptability
3. Can be used for penetrating processing of difficult-to-open materials
4. Compared with mechanical opening, there is no mechanical wear in any form between the opening process and the workpiece
Laser drilling is the earliest practical laser processing technology, and it is also one of the important application fields of laser processing. Laser drilling is mainly used for metal materials steel, platinum, molybdenum, tantalum, magnesium, germanium, silicon, light metal materials copper, zinc, aluminum, stainless steel, heat-resistant alloys, nickel matrix alloys, titanium gold, platinum, common carbide magnetic Materials and ceramic substrates, artificial gemstones, diamond films, ceramics, rubber, plastics, glass, etc. in non-metallic materials.