APPLICATION OF LASER CLEANING IN PRE-WELDING PRETREATMENT

Laser welding is a relatively common and mature field in the application of laser technology. The development of China’s manufacturing industry makes my country’s demand for welding continue to grow and may become the next flashpoint. For laser welding, welding quality is of the utmost importance. The welding quality is not only related to the laser welding process, laser selection, welding material types, etc., but also has a direct relationship with the surface state of the welded material. Then, how to do the pretreatment before laser welding, as a new generation of laser technology family, laser cleaning will be on the stage to remove the pollutants before welding, and also provide an “ultra-clear and non-destructive” welding substrate.

Laser Cleaning Technology

Simply put, it is to use the high-frequency vibration generated by a certain wavelength of laser to shatter the attachments on the surface of the object; use the instantaneous high temperature generated by the laser to make the attachments peel off the surface of the substrate, so as to achieve the purpose of cleaning.
The objects of laser cleaning include the pollution layer, paint layer, rust layer, adhesion layer, etc. on the surface of any material. Its applications mainly include: mold cleaning, metal surface paint and solder joint removal, oxides, etc.

Application of Laser Cleaning in Pre-Welding Pretreatment

Different from traditional shot blasting, sandblasting, grinding and other cleaning processes, the efficient, fast and non-contact cleaning method of laser cleaning is consistent with the development direction of my country’s industrial green environmental protection. In steel rails, ships, automobiles, military equipment, etc., there are broad prospects for development in the fields of pre-welding cleaning, painting and cleaning.
Taking railway rails as an example, the surface corrosion of railway rails consists of a multi-component mixture consisting of paper labels, oxide skin, rust, paint, grease, and dust.

There are many problems with traditional grinding and cleaning

1. Deep grinding ensures cleanliness, but destroys the camber appearance of the rail surface.
2. Reduce the amount of grinding to ensure the camber appearance, but lead to serious rust residues.
3. Consuming a lot of grinding wheel consumables has caused dust pollution to the environment and serious harm to the health of workers.
4. Railway maintenance and repair work is heavy.

Using laser cleaning can avoid the above problems and has the following advantages

1. The cleaning light source can be adapted to the arc shape of the rail to minimize the damage of the substrate, the corrosion removal rate is greater than 99%, and the substrate damage is less than 0.01 mm.
2. Laser cleaning can achieve selective removal of pollutants, improve cleanliness, and protect substrates.
3. Green cleaning technology without consumables, eliminating dust pollution and greatly reducing cleaning costs.
4. Greatly improve cleaning quality, improve welding yield, rail welding strength and reliability, and eliminate potential safety hazards.
The laser welding market is broad, and the corresponding demand for pre-welding pretreatment will also increase. Laser cleaning technology can achieve pre-welding pre-treatment without damage to the substrate and without secondary pollution, and is a good helper to ensure welding quality.

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