What are the contributions of laser in the field of cleaning

What are the contributions of laser in the field of cleaning

As a world-recognized manufacturing power, China has made great progress and great achievements in industrialization. At the same time, it also caused serious environmental degradation and industrial pollution. In recent years, China's environmental protection regulations have become more stringent, leading to the closure of some enterprises for rectification. A full-scale environmental storm has brought some shocks to the economy, and changing the traditional polluting production model is the key. With the advancement of technology, people gradually explore various technologies that are conducive to environmental protection, and laser cleaning technology is one of them. Laser cleaning technology is a newly applied workpiece surface cleaning technology in the past ten years. It is gradually replacing traditional cleaning technology in many fields with its own advantages and irreplaceability.

Traditional cleaning methods include mechanical cleaning, chemical cleaning and ultrasonic cleaning. Mechanical cleaning methods use mechanical means such as scraping, wiping, brushing, and sandblasting to remove surface dirt. The wet chemical cleaning method uses organic cleaning agents to remove surface deposits by spraying, spraying, soaking or high-frequency vibration. The ultrasonic cleaning method is to put the parts to be treated into the cleaning agent, and use the vibration effect generated by ultrasonic waves to remove the dirt. At present, these three cleaning methods still occupy a dominant position in my country's cleaning market, but they all produce pollutants to varying degrees, and their applications are greatly limited under the requirements of environmental protection and high precision.

Laser cleaning technology refers to the use of high-energy and high-frequency laser beams to irradiate the surface of the workpiece to instantly evaporate or peel off the dirt, rust spots or coatings on the surface, and quickly and effectively remove the attachments or coatings on the surface of the cleaned object, thereby realizing a clean laser process. Laser has the characteristics of high directivity, monochromaticity, high coherence and high brightness. By focusing lenses and Q-switching, the energy can be concentrated to a very small spatial and temporal scale. From the breakdown method, there are four laser cleaning methods:

Laser dry cleaning, that is, decontamination by direct radiation of pulsed laser;

Laser + liquid film method, that is, deposit a layer of liquid film on the surface of the substrate first, and then decontaminate it with laser radiation; when the laser is irradiated on the liquid film, the liquid film is rapidly heated to produce explosive vaporization, and the explosion shock wave causes dirt on the surface of the substrate loose. And with the shock wave flying away from the surface of the object to be treated, to achieve the purpose of decontamination.

The method of laser + noble gas, that is, when the laser is irradiated, the noble gas is blown to the surface of the substrate. When the dirt is peeled off the surface, it will be blown off the surface by the gas immediately, avoiding the re-contamination and oxidation of the surface;

After removing the dirt with a laser, clean it with a non-corrosive chemical method.

At present, due to the development of my country's high-end manufacturing industry and the continuous improvement of environmental protection requirements, the traditional cleaning technology (chemical method and mechanical polishing method) is far from meeting the needs of my country's industrial production, and the backwardness of cleaning technology restricts the normal operation of some important industries in my country. production and operations. Therefore, with the rapid development of China's high-end manufacturing industry, as a representative of green and efficient manufacturing, laser cleaning technology has a broad market scale.

Compared with traditional cleaning methods, laser cleaning is a "green" cleaning method with unparalleled advantages: no chemical reagents or cleaning solutions are required, and the cleaned waste is basically solid powder, small in size and easy to store , adsorption recovery, no photochemical reaction, no noise and environmental pollution, while not harming the health of operators, easy to achieve automatic control, and remote control of cleaning.

Wide application of laser cleaning in various fields

1. Mold cleaning.

The invention can realize the non-contact cleaning of the mold, is very safe for the surface of the mold, can ensure the accuracy, can clean the sub-micron dirt particles that cannot be removed by the traditional cleaning method, and realizes truly pollution-free, efficient and high-quality cleaning.

Precision disinfection and cleaning in the precision instrument industry. The precision machinery industry often requires chemical removal of esters and mineral oils used for lubricating and corrosion-resistant parts, and chemical cleaning often leaves residues. Laser degreasing can completely remove esters and mineral oils without damaging the surface of the part. The laser promotes the explosive gasification of the thin oxide layer on the surface of the part, creating a shock wave that removes dirt, rather than mechanically.

2. Clean the rails.

At present, the cleaning before rail welding adopts grinding wheel and abrasive belt grinding type cleaning. The substrate is seriously damaged and the residual stress is serious. In addition, a large number of grinding wheel consumables are consumed every year, resulting in high cost and serious dust pollution to the environment. Laser cleaning can provide high-quality, high-efficiency green cleaning technology for my country's high-speed railway track laying production, solve the above problems, eliminate welding defects such as seamless rail holes and gray spots, and improve the stability and safety of my country's high-speed railway operations.

3. Aviation.

After a period of time, the surface of the aircraft needs to be repainted, but before painting, the original old paint needs to be completely removed. Chemical soak/wipe is the dominant paint removal method in the aerospace field. This method creates a large amount of chemical auxiliary waste and does not allow for topical maintenance and paint removal. This process is labor-intensive and harmful to health. Laser cleaning can achieve high-quality paint removal from aircraft skin surfaces and is easy to automate production. At present, this technology has been applied to the maintenance of some high-end models abroad.

4. Ship field.

At present, the prenatal cleaning of ships is mainly carried out by sandblasting, which has caused serious dust pollution to the surrounding environment, and has been gradually banned, resulting in production reduction or even suspension of ship production enterprises. Laser cleaning technology will provide a green and pollution-free cleaning solution for ship surface anti-corrosion spraying.

5. Military industry.

Laser cleaning technology is widely used in weapon repair. Using the laser cleaning system, rust and contaminants can be removed efficiently and quickly, the cleaning location can be selected, and cleaning automation can be realized. Using laser cleaning not only has higher cleanliness than chemical cleaning processes, but also has little damage to the surface of the object.

Many of the above fields belong to the pillar industries of the national economy, and the economic and social benefits generated by laser cleaning technology are very considerable. Using the existing laser technology conditions in our country, it is entirely possible to develop matching laser cleaning equipment and realize practicality and industrialization in a short time, which is also of great significance to promoting the development of high-tech industries.

The development status and prospect of laser cleaning industry

Laser cleaning technology has been promoted and applied in Europe for several years, and products are already available. However, my country has just started, mainly because the investment of laser equipment is expensive and the general application is still difficult. The research of laser cleaning technology and the development of equipment in China basically follow the development of foreign countries. Although some achievements have been made in a short period of time, there is still a big gap compared with foreign countries.

In 2010, the Laser Fusion Center of China Institute of Engineering Physics took the lead in developing laser cleaning equipment in China, and successfully applied it to Yungang Grottoes, stone walls, stone statues, murals and other cultural relics. In the next few years, the number of papers on laser cleaning technology in domestic scientific research institutions has gradually increased, and the industry's attention to laser cleaning technology has gradually increased. Many companies try to develop laser cleaning equipment.

At present, China's laser cleaning industry is mainly concentrated in the four major industrial zones of the Pearl River Delta, the Yangtze River Delta, Central China and the Bohai Rim. Representative companies include Dazu Laser, Minglei Laser, Innovation Laser, Wuhan China Sanjiang Institute of Aeronautics and Astronautics, Ruike Laser, Beijing Guo Ke Century, Jiangsu Zhongke Sixiang, Dina Laser, Anshan Yuzi Laser.

As a green and efficient cleaning technology, laser cleaning technology has significant economic benefits and broad market prospects. However, the research on laser cleaning in my country is not enough. If we can use the existing laser technology to develop supporting laser cleaning equipment and put it into production to realize industrialization, we believe that with the reduction of laser cost, laser cleaning technology will be gradually promoted. Technological innovation and substitution can reduce pollution sources from the source and truly promote the implementation of my country's environmental protection work.

As an advanced technology in laser manufacturing, laser cleaning technology has great potential for application value in industrial development. Vigorously developing laser cleaning technology has important strategic significance for greatly enhancing the international competitiveness of my country's high-end laser manufacturing technology and equipment, as well as economic and social development. The relevant departments of national science and technology and environmental protection should pay more attention.