In the 1980s, the rapid development of the semiconductor industry put forward higher requirements for the cleaning technology of contaminated particles on the surface of silicon wafer masks. The key point is to overcome the great adsorption force between the contaminated particles and the substrate. Traditional chemical cleaning, mechanical cleaning, and ultrasonic cleaning methods cannot meet the needs, while laser cleaning can solve such pollution problems, and related research and applications have been rapidly developed. In 1987, there was the first patent application for laser cleaning.
 

After entering the 1990s, Zapka et al. successfully applied laser cleaning technology to semiconductor manufacturing processes, removing microparticles on the mask surface, and achieving the early application of laser cleaning technology in the industrial field. In 1995, researchers successfully achieved the cleaning of aircraft fuselage paint using a 2kW TEA-CO2 laser. After entering the 21st century, with the rapid development of Ultrashort pulse lasers, the research and application of laser cleaning technology at home and abroad has gradually increased, focusing on the cleaning of metal material surfaces. Typical applications abroad include aircraft body paint removal, mold surface oil stain removal, engine internal carbon deposition removal and joint surface cleaning before welding.

Steel is most widely used in industry, such as automobile welding, shipbuilding, painting, and turbine blade manufacturing. Laser cleaning technology can remove rust, paint, and dirt from the surface of steel components, thereby ensuring welding quality and painting effect. Laser cleaning technology was used to clean the surface of marine carbon steel plates before welding. The research results showed that the working speed of laser cleaning can be increased to 1000mm/min by increasing the average power or increasing the laser light source. The mechanism of laser ablation includes physical and chemical effects and elastic vibration effects.

With different laser energy density, the two effects have different degrees of influence on the cleaning mechanism. The damping oscillation propagation law of laser induced plasma shock wave in materials was found, and an online monitoring system for the laser cleaning process was established. The relationship between oxide removal degree, plasma luminous intensity, and sound wave duration was established. In addition to completely removing surface rust, laser can also form a very thin hardening layer on the surface of the substrate. The hardening layer can effectively improve the hardness of the carbon steel surface, play a surface strengthening role, and to some extent protect the carbon steel.

Laser cleaning technology can not only be applied to the surface cleaning of aluminum alloy before welding, but also to the surface treatment before aluminum alloy bonding. Similar studies have compared the effects of low-pressure plasma treatment and laser cleaning on the shear strength of adhesive joints. The results show that the average shear strength of laser cleaning samples is 19.35MPa, which is about 5MPa higher than that of plasma treatment.

When laser cleaning, it is necessary to select appropriate parameters such as laser wavelength, pulse width, and pulse frequency based on different cleaning objects. The vast majority of domestic and foreign research on laser cleaning of coatings and small particles has chosen nanosecond pulse fiber lasers with a wavelength of 1064nm. However, there is a significant difference in the laser pulse frequency between the two. The former has a pulse frequency of several thousand to several tens of kilohertz, and the surface roughness after cleaning can reach 1 μ The latter is concentrated in the range of a few hertz to several tens of hertz, with a removal rate of over 90%.

Domestic scholars have conducted research in the field of laser cleaning relatively late, coupled with the high cost of short pulse lasers themselves, which require higher cleaning efficiency to achieve high value in practical applications. Therefore, there are currently very few related applications. In recent years, some universities, research institutes, and enterprises in China have successively carried out research on the application of laser cleaning technology in the industrial field, and have also manufactured laser cleaning equipment.

The China Academy of Engineering Physics has carried out research on the removal of mold release agents for tire molds, paint removal of aircraft wings and radomes (composite materials) and tank armor, and rust removal of marine parts. Suzhou University has conducted research on rust removal of automotive volutes, track maintenance and dirt removal, and scale removal of insulating porcelain bottles.

The above summarizes the current research status of laser cleaning at home and abroad. In terms of theory and technology, although a large number of experiments have been carried out in the process research of laser cleaning both domestically and internationally, the theory and mechanism research of laser cleaning is still incomplete. Although relevant physical models have been established, these models still have significant limitations. In terms of practical application, there is a significant gap between China and foreign countries.

About HGTECH

HGTECH is the pioneer and leader of laser industrial application in China, and the authoritative provider of global laser processing solutions. We comprehensively layout the construction of laser intelligent equipment, measurement and automation production lines, and smart factories to provide an overall solution for intelligent manufacturing.

We deeply grasp the development trend of manufacturing industry, constantly enrich products and solutions, adhere to exploring the integration of automation, informatization, intelligence and manufacturing industry, and provide various industries with laser cutting systems, laser welding systems, laser marking series, laser texturing complete equipment, laser heat treatment systems, laser drilling machines, lasers and various supporting devices The overall plan for the construction of special laser processing equipment and plasma cutting equipment, as well as automatic production lines and smart factories.