In recent years, with the enhancement of people's awareness of environmental protection, it has brought huge challenges to the development of the cleaning industry around the world. Various cleaning technologies that are conducive to environmental protection have emerged as the times require, and then laser cleaning equipment appeared.

1. Overview of laser cleaning machine

The so-called laser cleaning technology refers to the use of high-energy 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 effectively remove the surface attachments or surface coatings of the cleaning object at high speed, so as to achieve a clean process. . It is a new technology based on the interaction effect of laser and matter. Compared with traditional cleaning methods such as traditional mechanical cleaning method, chemical corrosion cleaning, liquid solid strong impact cleaning, and high-frequency ultrasonic cleaning, it has obvious advantages. It is efficient, fast, low cost, small thermal load and mechanical load on the substrate, non-destructive cleaning; recyclable waste, no environmental pollutants, safe and reliable, does not damage the operator's health certificate, can remove a variety of different thickness, different The sub-cleaning process of the coating of the components is easy to realize automatic control, and realize long-distance remote control cleaning, etc.

2. Principle and method of laser cleaner

Lasers are characterized by high directivity, monochromaticity, high coherence and high brightness. Through the focusing and Q-switching of the lens, the energy can be concentrated into a small spatial and temporal range. In the laser cleaning process, the following characteristics of the laser are mainly used:

1. The laser can achieve a high concentration of energy in time and space. The focused laser beam can generate a high temperature of several thousand degrees or even tens of thousands of degrees near the focus, causing the dirt to evaporate, vaporize or decompose instantly.

2. The divergence angle of the laser beam is small and the directionality is good. The laser beam can be collected into different diameters of light spots through the light-condensing system. Under the condition of the same laser energy, controlling the laser beam spots of different diameters can adjust the energy density of the laser and make the dirt expand by heat. When the expansion force 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-mentioned lasers to achieve the purpose of cleaning. According to the optical characteristics of the substrate to be cleaned and the dirt to be removed, the laser cleaning mechanism can be divided into two categories:

One is to use the cleaning substrate (also known as the parent body) and the surface attachment (dirt) to have a large difference in the absorption coefficient of a certain wavelength of laser energy. Most of the laser energy radiated to the surface is absorbed by the surface attachments, so it is heated or vaporized, or expands instantaneously, and is driven by the formed airflow to be separated from the surface of the object to achieve the purpose of cleaning. However, the substrate will not be damaged due to the extremely small absorption energy of the laser at this wavelength. For this type of laser cleaning, selecting the appropriate wavelength and controlling the laser energy is the key to achieving safe and efficient cleaning.

Another type of cleaning method is suitable for cleaning the substrate and surface attachments with little difference in the laser energy absorption coefficient, or the substrate is more sensitive to the acidic vapor formed by the heating of the coating, or the coating will produce toxic substances after heating. This type of method usually uses a high-power, high-repetition-rate pulsed laser to impact the surface to be cleaned, converting part of the beam into acoustic waves. After the sound wave hits the lower hard surface, the returning part interferes with the incident sound wave generated by the laser, generating high-energy waves, causing the coating to explode in a small range, the coating is pressed into powder, and then removed by a vacuum pump, the underlying substrate will not damage.