Laser Cleaning Technology Principle and Application Analysis in High-End Manufacturing

Laser cleaning is a new surface treatment technology that has developed rapidly in recent years. Compared with traditional surface cleaning methods, laser cleaning offers advantages such as high cleanliness, high efficiency, low cost, no damage to components during cleaning, environmental friendliness, and safety and reliability. It has now been gradually applied in high-end manufacturing, as well as in the maintenance and servicing of precision products.

Laser cleaning is a new surface treatment technology that has developed rapidly in recent years. Compared with traditional surface cleaning methods, laser cleaning offers advantages such as high cleanliness, high efficiency, low cost, no damage to components during cleaning, environmental friendliness, and safety and reliability. It has now been gradually applied in high-end manufacturing, as well as in the maintenance and servicing of precision products.

In the high-end manufacturing industry, when industrial products are electroplating, phosphating, spraying, welding and assembling, in order to ensure the quality of the workpiece, it is necessary to remove the dirt, grease, dust, rust and other pollutants on the surface of the product. At present, the most commonly used surface cleaning method is Mechanical cleaning method and chemical cleaning method, with the increasingly strict requirements of environmental protection regulations in my country and the continuous development of precision and high-end products, traditional cleaning methods have been unable to meet the requirements of high surface cleanliness, high efficiency, low cost and high quality. Environmentally friendly cleaning requirements.

In order to meet the increasingly high surface cleaning needs of the high-end manufacturing industry, laser cleaning technology came into being. Laser cleaning technology is considered to be the most efficient cleaning technology due to its cleaning characteristics such as no force, no chemical reaction, no thermal effect and suitable for various materials. Reliable and most effective surface treatment technology.

2 The principle of laser cleaning technology

Laser cleaning technology mainly utilizes the following characteristics of lasers:

(1) The laser can achieve a high concentration of energy through the lens, and the focused laser beam can generate a high temperature of several thousand degrees or even tens of thousands of degrees at the focal point, causing the dirt to evaporate, vaporize or decompose instantly.

(2) The emission angle of the laser beam is small and the directionality is good, and the laser beam can be collected into light spots of different diameters through the light collecting system. Under the condition of the same laser beam energy, controlling the laser beam spots of different diameters can adjust the energy density of the laser. When the expansion force of the thermal expansion of the dirt is greater than the adsorption force of the dirt on the substrate, the dirt will be separated from the surface of the object.

(3) The laser beam can generate mechanical resonance by generating ultrasonic waves on the solid surface, so that the dirt can be broken and fallen off.

Laser cleaning technology utilizes the characteristics of the above laser to achieve the purpose of cleaning. According to the optical characteristics of the cleaned substrate and the removed dirt, the laser cleaning mechanism can be divided into two categories:

One is the cleaning method in which the absorption coefficient of the laser energy of a certain wavelength is greatly different between the cleaned base material and the surface attachment. In this case, the laser should select the wavelength with the largest absorption coefficient of the surface attachments. When the laser of this wavelength is radiated to the surface of the base metal, most of the laser energy is absorbed by the surface attachments, the attachments expand instantly when heated, and the adhesion drops sharply and automatically falls off. Or vaporize and evaporate, so as to achieve the purpose of cleaning.

The other type is the cleaning method in which the laser energy absorption coefficient of the cleaned base material and the surface attachments is not much different, or the surface attachments will form acid vapors when heated, or the surface attachments will produce toxic substances when heated. This type of method usually uses a high-power and high-repetition-rate pulsed laser to impact the surface of the base metal to be cleaned, so that part of the beam is converted into sound waves. After the sound waves hit the underlying hard surface, the returned part interferes with the incident sound waves generated by the laser, resulting in The high-energy wave causes a small-scale explosion of the surface attachments, the attachments are pressed into powder, and then removed by the vacuum pump, while the underlying base metal will not be damaged.

3 Advantages of laser cleaning technology

Compared with traditional mechanical cleaning methods and chemical cleaning methods, laser cleaning technology has the following advantages:

(1) Effect advantage: The traditional cleaning method is contact cleaning, which has disadvantages such as easy damage to the surface of objects, incomplete cleaning or secondary pollution of the cleaning medium. Laser cleaning can be cleaned with high cleanliness without damaging the surface of the object, and no dirt remains.

(2) Environmental advantages: Laser cleaning uses pulsed laser radiation for decontamination, does not use any solvent, does not produce additional substances, has no photochemical reaction, and avoids the noise generated by mechanical cleaning, which can easily solve the environmental pollution caused by chemical cleaning. question.

(3) Control advantages: The laser can be transmitted through the optical fiber, which is convenient for long-distance operation, and can clean the places that are difficult to reach or dangerous by traditional methods.

(4) Convenience advantage: Laser cleaning technology can remove various types of contaminants on the surface of various materials by selecting different laser powers and pulse frequencies to achieve high cleanliness, and can also selectively clean the surface of the base metal of pollutants.

 

(5) Cost advantage: Laser cleaning has fast speed, high efficiency and low operating cost, which can save a lot of time for assembly line production, and laser cleaning equipment is easy to automate operations, further improving production efficiency.

4 Application of laser cleaning in high-end manufacturing

4.1 Surface cleaning in the production process of high-end manufacturing

When high-end products are electroplating, phosphating, spraying, welding, and assembling, they must remove grease, dust, rust and other pollutants on the surface of the product, and use traditional chemical cleaning processes and mechanical cleaning processes to clean them, which is inconvenient to operate and takes time. Long time, low production efficiency, and mechanical cleaning is easy to damage the surface of the product, chemical cleaning is time-sensitive (after chemical cleaning, it is required to carry out the next work within 24 hours, otherwise it should be cleaned again). Using laser cleaning technology, all kinds of pollutants on the surface of products can be removed in real time, efficiently, quickly and selectively, and the cleanliness of laser cleaning is higher than that of traditional cleaning processes. At the same time, laser cleaning technology can also be used to remove rust and corrosion defects of various raw materials, parts and fixtures due to long-term storage or use.

 

4.2 Maintenance of high-end manufactured products

High-end manufactured products need to be maintained after a period of use or storage. The biggest workload is repainting and maintenance of the surface. Before painting, the original old paint needs to be completely removed. The current method is solvent cleaning and mechanical cleaning, which requires labor. High strength, low efficiency, and unclean cleaning. Solvents, gasoline, and alcohol endanger the health of employees and easily cause damage to the product surface. If laser cleaning technology is used, the old paint on the product surface can be efficiently and selectively cleaned. At the same time, the laser cleaning technology can selectively clean the surface of the parts that need to be repaired in the post-maintenance process of the product.