Why can laser be used for cleaning? What are the advantages
2024-11-12
There are various cleaning methods in the traditional cleaning industry, most of which are chemical agents and mechanical methods. After 2020, when my country's environmental protection regulations are becoming more and more stringent and people's environmental protection and safety awareness are increasing, the types of chemicals that can be used in industrial production cleaning will become fewer and fewer. How to find a cleaner and non-destructive cleaning method is a problem we have to consider. Laser cleaning has the characteristics of no grinding, non-contact, no thermal effect, and is suitable for objects of various materials. It is considered to be the most reliable and effective solution.
First, let's understand the nature of lasers. Simply put, lasers are no different from the light (visible and invisible light) that follows us like a shadow, except that lasers use resonant cavities to focus light in the same direction, and have simpler wavelengths, better coordination and other properties. Therefore, in theory, all wavelengths of light can be used to form lasers, but in fact, due to the limited number of media that can be excited, the laser light sources that can be 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 widely used in laser cleaning.
Academically speaking: laser ablation (scientific name for 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. At 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, the material can be ablated with a continuous wave laser beam. Deep ultraviolet excimer lasers are mainly used for photoablation. The laser wavelength used for photoablation is about 200 nm. The depth of absorption of laser energy and the amount of material removed by a single laser pulse depend on the optical properties of the material as well as the laser wavelength and pulse length. The total mass ablated from the target by each laser pulse is usually called the ablation rate. Laser radiation characteristics such as laser beam scanning speed and scanning line coverage can significantly affect the ablation process.
Compared with traditional cleaning methods such as mechanical friction cleaning, chemical corrosion cleaning, liquid solid strong impact cleaning, and high-frequency ultrasonic cleaning, laser cleaning has obvious advantages.
1. Laser cleaning is a "green" cleaning method that does not require the use of any chemical agents or cleaning fluids. The waste materials cleaned are basically solid powders with small size, easy to store and recyclable, which can easily solve the environmental pollution problems caused by chemical cleaning;
2. Traditional cleaning methods are often contact cleaning, which has mechanical force on the surface of the cleaning object, damaging the surface of the object or the cleaning medium is attached to the surface of the cleaned object and cannot be removed, resulting in secondary pollution. The non-abrasive and non-contact nature of laser cleaning solves these problems;
3. Lasers can be transmitted through optical fibers, and can be used in conjunction with manipulators and robots to easily achieve long-distance operation. They can clean parts that are difficult to reach with traditional methods, which can ensure the safety of personnel in some dangerous places;
4. Laser cleaning can remove various types of pollutants on the surface of various materials to achieve a cleanliness that cannot be achieved by conventional cleaning. It can also selectively clean pollutants on the surface of materials without damaging the surface of the materials;
5. Laser cleaning is efficient and saves time;
6. Although the initial one-time investment in purchasing a laser cleaning system is high, the cleaning system can be used stably for a long time, with low operating costs, and only electricity costs per hour.