Why Laser Cleaning Can Do No Harm to the Surface Of the Material？

When it comes to lasers, most people think of the indestructible high-energy laser beam. If it is used for cleaning, the first thing everyone considers is whether the high-energy laser will damage the surface of the material.

HANTENCNC briefly introduces the principle of pulse laser cleaning without damaging the surface of the material.

1. The high-energy pulsed beam is absorbed by the contaminants on the surface of the substrate.

2. The absorption of large energy causes a rapidly expanding plasma (a highly ionized unstable gas) to be formed around the pollutant, generating a shock wave, which turns the pollutant into fragments and is removed.

3. Although energy-absorbing pollutants have a higher temperature, they will leave the surface of the material at a high speed under the action of the formed shock wave, taking away most of the heat, and only a very small amount of heat is absorbed by the material through conduction and removed. Although the surface of the contaminated material will receive laser irradiation again, the metal has a very low absorption rate of laser light in this waveband, and most of the laser light is reflected, so the material will not rise significantly. The thicker the material, the surface will heat up. The smaller the effect.

4.To change the structure of steel materials, the corresponding phase transition temperature needs to be reached. To form a surface hardening effect, for conventional carbon steel, it must be heated to at least 860℃, and it needs to be kept for a certain period of time. If the martensite structure is to form a tempering effect, at least it must be kept at about 200°C for a certain period of time. The actual laser cleaning is completed in an instant. It is this feature that makes laser cleaning can effectively avoid changes in the mechanical properties or hardness of metal materials. Reasonable control of process parameters can achieve non-destructive cleaning of mirror molds.