As a world recognized manufacturing power, China has made great strides and achievements on the road of industrialization. At the same time, it has also led to serious environmental degradation and industrial pollution. In recent years, China’s environmental protection laws and regulations have become more and more strict, resulting in some enterprises being shut down for rectification. The one size fits all environmental storm has some impact on the economy, and changing the traditional pollution production mode is the key. With the progress of technology, people have gradually explored various technologies conducive to environmental protection, and laser cleaning technology is one of them. Laser cleaning technology is a newly applied workpiece surface cleaning technology in recent ten years. It is gradually replacing the traditional cleaning technology in many fields with its own advantages and irreplaceable.
Traditional cleaning methods include mechanical cleaning, chemical cleaning and ultrasonic cleaning. Mechanical cleaning uses mechanical means such as scraping, wiping, brushing and sand blasting to remove surface dirt; Wet chemical cleaning method uses organic cleaning agent to remove surface attachments by spraying, drenching, soaking or high-frequency vibration; Ultrasonic cleaning method is to put the treated parts into the cleaning agent and remove the dirt by using the vibration effect produced by ultrasonic. At present, these three cleaning methods still occupy a dominant position in China’s cleaning market, but they will produce pollutants to varying degrees, and their application is 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 beam to irradiate the workpiece surface, so that the dirt, rust or coating on the surface can evaporate or peel off instantly, and effectively remove the attachment or surface coating on the surface of the cleaning object at high speed, so as to achieve a clean laser process. Laser is characterized by high directivity, monochromaticity, high coherence and high brightness. Through the focusing of the lens and Q-switch, the energy can be concentrated in a very small space and time range. In terms of methods, there are four laser cleaning methods:
1.Laser dry cleaning method, i.e. direct radiation decontamination by pulsed laser;
2.Laser + liquid film method, that is, first deposit a layer of liquid film on the substrate surface, and then decontaminate with laser radiation; When the laser irradiates the liquid film, the liquid film is heated rapidly, resulting in explosive vaporization, and the explosive shock wave loosens the dirt on the surface of the substrate. And fly away from the machined object surface with the shock wave to achieve the purpose of decontamination；
3.The method of laser + inert gas, that is, while laser radiation, inert gas is blown to the substrate surface. When the dirt is stripped from the surface, it will be blown away from the surface immediately by gas to avoid re pollution and oxidation of the surface;
4.After the dirt is loosened by laser, it is cleaned by non corrosive chemical method.
At present, due to the development of China’s high-end manufacturing industry and the continuous improvement of environmental protection requirements, Traditional cleaning technologies (chemical method and mechanical grinding method) are far from meeting the needs of China’s industrial production. The backwardness of cleaning technology restricts the normal production and operation of some important industries in China. Therefore, as a representative of green and efficient manufacturing, laser cleaning technology has a broad market scale under the rapid development of China’s high-end manufacturing industry.
Compared with traditional cleaning methods, laser cleaning is a “green” cleaning method, which has incomparable advantages: it does not need to use any chemical agent and cleaning solution, and the cleaned waste is basically solid powder, which has small volume, easy storage, adsorption and recovery, no photochemical reaction, no noise and environmental pollution, At the same time, it does not damage the health of operators, and is easy to realize automatic control and remote control cleaning.
