The purpose of pre-cleaning before metal welding is to remove the oxide layer, rust layer and oil stains on the metal surface, which is an important measure to prevent the formation of pores and slag inclusions. Now the commonly used methods are chemical cleaning and mechanical cleaning, and these two methods have their own advantages and disadvantages. Mechanical grinding can easily cause damage to the workpiece, and it is difficult to deal with complex surface processing. It also has high noise pollution and high work intensity of workers. Chemical cleaning is not suitable for local cleaning, which is easy to cause environmental pollution.

　　Metal welding is cleaned before because oil, rust, water, paint, oxide skin, dust and other debris on the metal can cause welding defects, such as pores, slag inclusions, unfused, etc., so it should be cleaned.

　　In the face of pre-welding treatment, the traditional treatment is to use grinding or potion, which can damage the substrate or cause some environmental pollution. The laser cleaner is an environmentally friendly device. During use, there are no other consumables and no waste, so it will not cause pollution to the environment.

　　Laser cleaning has the following advantages:

　　1. Green cleaning: without the use of any chemicals, the cleaned waste is solid and harmless powder, which can completely solve the problem of environmental pollution caused by chemical cleaning.

　　2. Non-destructive cleaning: non-abrasive, non-contact, and no damage to the substrate during cleaning.

　　3. Low-cost cleaning: The equipment consumes very little power during operation.

　　4. Precision and precision cleaning: It is possible to perform precision and precision cleaning on designated areas.

　　5. Automated cleaning: It can be equipped with automated equipment to achieve automated cleaning.

　　The efficient, fast and non-contact cleaning method of laser cleaning is consistent with the development direction of China's industrial green environmental protection. In the fields of rails, ships, automobiles, military equipment, etc., laser cleaning can effectively improve the quality of welding before and after welding, and has broad development prospects.