Laser Cleaning:Definition,Types,Advantages,5 Uses

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What is laser cleaning?

Laser cleaning or laser surface cleaning refers to the technique of utilizing the laser irradiation phenomenon for removing the impurities and contaminants off the surface of a material. The process of laser cooling involves the removal of a fine upper layer of the given material to get rid of the surface contaminants entirely.

Generally, the process of laser surface cleaning requires a very high power laser beam with very brief laser pulses.

laser cleaning
An industrial laser cleaning machine. Image source: Optola, Industrinė lazerinio valymo įranga, CC BY-SA 4.0

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How does laser cleaning work?

Laser cleaning involves the use of laser irradiation phenomenon for removing the impurities and contaminants off the surface of a material. A high power laser with brief laser pulses is selected for the process. The laser energy is directed to ablate the upper layer of the material. While some part of the contaminants and impurities vaporize after the ablation process, some remain as particulate dust. This dust can be then collected in the filtration system later. This ablation process is repeated till the required thickness of the upper layer of the material is removed.

What are the types of laser cleaning processes?

Laser cleaning processes can be divided into two distinct types:

Coating removal:

This type of laser surface cleaning, as the name suggests, refers to the removal of impurities and contaminants off the surface of a material with the help of lasers. In this process, the chemical and physical composition of the impurity layer is significantly different from that of the substrate. The organic material absorbs the laser light while the non-organic substrate does not get affected in any way. No mechanical, chemical, or physical change is observed on the substrate. Examples of application of this process include paint, rubber coating, and insulation.

Laser surface decontamination:

The process of laser surface decontamination involves the removal of contaminants and impurities present deep within the surface of the given material. This process physically removes the entire upper layer of the material. Examples of application of this process include removal of concrete radioactive layers with the help of laser scabbling technique.

Lasis
Laser ablation in a solution. image source: Sahehco, Lasis, CC BY-SA 4.0

What are the advantages of laser cleaning?

Advantages of laser surface cleaning are:

  • Laser surface cleaning is a non-contact process, which makes it extremely convenient for application.
  • Laser surface cleaning does not involve the use of abrasives or bad chemicals.
  • Laser surface cleaning does not produce any form of secondary waste.
  • Laser surface cleaning allows fine layer removal without compromising with the structure or shape of the material.
  • Laser surface cleaning does not produce any chemical, physical, or mechanical change in the substrate.
  • Laser surface cleaning can be conducted by machines and robots, eliminating the risk of workers being exposed to radiation.
  • Laser surface cleaning is a flexible technique.

What are the uses of laser cleaning?

  • Laser surface cleaning is used for several purposes nowadays. It is used in both macro-scale and large-scale industries for several cleaning purposes. Impurities like dust, paint, radioactive elements, etc. are removed by lasers.
  • In the electronic industry, laser surface cleaning is used for cleaning the contact areas of pads and plugs and also for removing the insulation from electrical cables.
  • In the rubber industry, lasers are used for cleaning the surface of rubber or tire molds. In certain materials use of chemicals are impossible for cleaning; laser cleaning proves to be useful for such materials.
  • The removal of paint layers from buildings, aircraft, ships, cars, etc. also involves the application of laser surface cleaning.
  • Fine cleaning in microchips is also performed by lasers. Laser surface cleaning is a common rust, oil, and grease removing method also.
Laser Ablation of Asteroid Like Sample
Ablation of an irregular surface by using lasers. Image source: Travis Brashears, Laser Ablation of Asteroid Like Sample, CC BY 4.0

What type of lasers are used for laser cleaning?

Generally, high-power optical lasers are used for laser surface cleaning. Fiber lasers produce and direct laser light by using a flexible medium that allows better and easier conveyance of the light beam to its required destination. The power output of optical Fiber-based lasers is higher than the other types of lasers. The high surface area to volume ratio of these laser variants provides a continual output power of kilowatt range along with efficient cooling. The optical fiber waveguide contributes to reducing the optical path distortion due to thermal issues. Optical fiber-based lasers generally have a more compact design compared to gas or solid-state lasers (of the same power output) and produce a diffraction-limited laser beam.

Apart from fiber-optic lasers, Nd:YAG lasers are also used for laser surface cleaning. Nd:YAG lasers are used for emitting light in the infrared range (near 946, 1064, 1120, 1320, and 1440 nm). Organic samples (surface impurities) are made up mostly of water and are capable of absorbing the IR frequency of light well.

Powerlite NdYAG 3
Nd: YAG (neodymium-doped yttrium aluminum garnet) laser. image source: Kkmurray, Powerlite NdYAG, CC BY 3.0

To know more about optical fiber lasers visit https://techiescience.com/fiber-lasers/

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