For example, when there are sub-micron pollution particles on the surface of the workpiece, these particles tend to stick very tightly. Conventional cleaning methods cannot remove them. However, it is very effective to clean the surface of the workpiece with nano laser radiation. Also, because the laser cleans the workpiece without contact, it is very safe to clean the precision workpiece or its fine parts, and its accuracy can be ensured. Therefore, laser cleaning has unique advantages in the cleaning industry.
Why can laser be used for cleaning? Why does it not cause damage to the object being cleaned? First understand the nature of laser. To put it simply, lasers are no different from the shadowy light (visible light and invisible light) around us, except that the laser uses a resonant cavity to gather light in the same direction, and has a simpler wavelength, coordination, etc. The performance is better, so in theory all wavelengths of light can be used to form lasers, but in fact, it is limited by the fact that there are not many media that can be excited, so the laser light sources that can produce stable and suitable for industrial production are quite limited. The most widely used ones are probably Nd:YAG lasers, carbon dioxide lasers and excimer lasers. Since Nd: YAG laser can be transmitted through optical fiber and is more suitable for industrial applications, it is also used in laser cleaning.
Academically speaking: Laser ablation (the scientific name of laser cleaning) or photoablation is the process of removing material from a solid (or sometimes liquid) surface by irradiating it with a laser beam. At low laser flux, the material is heated by the absorbed laser energy and evaporates or sublimates. Under high laser flux, the material is usually converted to plasma. Generally, laser ablation refers to the removal of material with a pulsed laser, but if the laser intensity is high enough, a continuous wave laser beam can be used to ablate the material. Excimer lasers of deep ultraviolet light are mainly used for photoablation. The wavelength of the laser used for photoablation is about 200 nm. The depth of laser energy absorption and the amount of material removed by a single laser pulse depends on the optical properties of the material and the laser wavelength and pulse length. The total mass of each laser pulse ablated from the target is often referred to as the ablation rate. Laser radiation characteristics such as laser beam scanning speed and scanning line coverage will significantly affect the ablation process.
