Published in：2018-09-14Views：416 Times
The traditional cleaning industry has a variety of cleaning methods, mostly using chemical and mechanical methods for cleaning. In China, environmental protection regulations are becoming more and more strict, people's awareness of environmental protection is increasing, and the types of chemicals that can be used in industrial production cleaning will become less and less.
How to find a cleaner, non-damaging cleaning method is a problem we have to consider. Laser cleaning has the characteristics of no grinding, non-contact, no heat effect and cleaning of objects suitable for various materials, and is considered to be a reliable and effective solution. At the same time, laser cleaning can solve problems that cannot be solved by traditional cleaning methods.
The physical principle of laser cleaning
The beam emitted by the laser is absorbed by the layer of contaminants on the surface to be treated. The absorption of large energy forms a rapidly expanding plasma (a highly ionized unstable gas) that produces a shock wave. The shock wave turns the contaminants into pieces and is rejected. Laser cleaning has five advantages over traditional cleaning methods such as mechanical friction cleaning, chemical corrosion cleaning, liquid solid impact cleaning, and high frequency cleaning:
Laser cleaning is a “green” cleaning method. It does not need to use any chemicals and cleaning liquid. The washed waste is basically solid powder, small in size, easy to store, recyclable, no photochemical reaction, no pollution. Environmental pollution problems caused by chemical cleaning can be easily solved. A blower can often solve the waste problem caused by cleaning.
The traditional cleaning method is often contact cleaning, which has mechanical force on the surface of the cleaning object. The surface of the damaged object or the cleaning medium adheres to the surface of the object to be cleaned, cannot be removed, and causes secondary pollution. No laser grinding or contacting and no heat effects do not damage the substrate, making these problems easy to solve.
The laser can be transmitted through optical fiber, and cooperates with the robot hand and the robot to easily realize long-distance operation and clean the parts that are difficult to reach by traditional methods.
Laser cleaning cleans all types of contaminants on the surface of various materials to the level of cleanliness that cannot be achieved with conventional cleaning. It is also possible to selectively clean contaminants on the surface of the material without damaging the surface of the material.
The laser cleaning speed is fast, the efficiency is high, and the time is saved. Although the laser cleaning system is purchased at a high level in the early stage, the cleaning system can be stably used for a long time, the running cost is low, and more importantly, the automatic operation can be conveniently realized.
Introduction to laser cleaning in various fields
Laser cleaning technology is a new cleaning technology that has developed rapidly in the past 10 years. It has gradually replaced traditional cleaning processes in many fields with its own advantages and irreplaceability. Laser cleaning can be used not only to clean organic contaminants, but also to clean inorganic materials, including metal rust, metal particles, dust, etc. Here are some practical applications. These technologies are very mature and have been widely used.
1. Mold cleaning
Every year, tire manufacturers manufacture hundreds of millions of tires. The cleaning of tire molds in the production process must be fast and reliable to save downtime. Conventional cleaning methods include sand blasting, carbon dioxide cleaning, etc., but these methods usually have to be cooled in a hot mold for several hours, then moved to a cleaning device for cleaning, which takes a long time to clean and easily impairs the accuracy of the mold. Solvents and noise can also cause environmental problems.
Laser cleaning method, because the laser can be transmitted by optical fiber, it is very flexible in use; since the laser cleaning method can use optical fiber connection to guide the light to the dead corner of the mold or the hard-to-clean part, it is convenient to use; No gasification, so it will not produce toxic gases, affecting the working environment.
The technology of laser cleaning tire molds has been widely used in the tire industry in Europe and the United States. Although the initial investment cost is high, the benefits obtained by saving standby time, avoiding mold damage and saving raw materials can be recovered.
2. Weaponry equipment cleaning
Laser cleaning technology is widely used in weapon maintenance. The laser cleaning system can quickly remove rust and contaminants, and can select the cleaning parts to automate the cleaning. It is cleaned with laser and has high cleanliness without damaging the surface of the object.
By setting different parameters, a dense oxide protective film or metal molten layer can be formed on the surface of the metal object to improve surface strength and corrosion resistance. Laser-cleared waste is basically non-contaminating to the environment, and can be operated remotely, reducing damage to the operator.
3. Aircraft old paint cleaning
Laser cleaning systems in Europe have been used in the aerospace industry. The surface of the aircraft is repainted after a period of time, but the original old paint needs to be removed before painting. Traditional mechanical paint removal methods can easily damage the metal surface of an aircraft.
4. Cleaning of building facades
With the rapid development of China's economy, more and more skyscrapers have been built, and the cleaning problem of the exterior walls of the building has become increasingly prominent. The laser cleaning system provides a solution to the cleaning of the external walls of buildings through optical fibers. Various pollutants on stone, metal and glass are cleaned and the cleaning efficiency is high. It can also clean black spots and stains on various stone materials in buildings.
5. Cleaning in the electronics industry
The electronics industry uses lasers to remove oxides: the electronics industry requires high-precision decontamination and is suitable for laser deoxidation. Before the board is soldered, the component pins must be de-oxidized to ensure electrical contact and do not damage the pins during the decontamination process.
6. De-ester cleaning in the precision instrument industry
The precision machinery industry often needs to remove esters and mineral oils used to lubricate and resist corrosion on parts, usually by chemical means, while chemical cleaning has residues. Laser deesterification removes esters and mineral oils without damaging the surface of the part. The removal of contaminants is done by shock waves, and the thin layer of oxide on the surface of the part is explosively vaporized to form a shock wave, resulting in the removal of dirt rather than mechanical interaction. Material deesterification is used for the cleaning of mechanical parts in the aerospace industry. Oil ester removal in mechanical part processing can also be done by laser cleaning.
7. Pipe cleaning in nuclear power plant reactor
The laser cleaning system is also used for cleaning pipelines in nuclear power plant reactors. It uses optical fiber to introduce high-power laser beam into the reactor to directly remove radioactive dust, and the cleaned material is easy to clean. And it is a long distance operation.
In summary, laser cleaning plays an important role in many fields, and in automotive manufacturing, semiconductor wafer cleaning, precision parts processing, military equipment cleaning, building exterior cleaning, heritage protection, circuit board cleaning, precision parts. Processing, manufacturing of liquid crystal displays, and removal of chewing gum have played an important role.
The application of laser cleaning in defense military equipment: such as various aircraft stripping and derusting, various ship equipment, various weapons and equipment derusting, various tank artillery derusting, various parts rust removal, etc., broad prospects The development trend has great potential. In particular, the advantages of environmental protection, convenience, and low-cost use of laser cleaning are new process technologies.