In the fields of modern industrial manufacturing and precision maintenance, the demand for efficient, environmentally friendly and non-destructive cleaning is becoming increasingly urgent. Traditional cleaning methods such as chemical solvents, sandblasting or mechanical grinding often come with problems such as environmental pollution, substrate damage or low efficiency. At this point, a revolutionary technology - laser cleaning, with its unique "eraser of light" feature, is bringing about a disruptive change to surface cleaning. What on earth can it erase? Let's find out.
Laser cleaning technology is an advanced cleaning technique that uses high-energy laser beams to irradiate the surface of objects, causing impurities, contaminants or coatings to evaporate or peel off rapidly through optical and thermal effects. When a laser beam is directed onto the surface of an object, the laser energy is absorbed and exerts a thermal effect on the pollutant within a very short period of time, causing the surface temperature of the pollutant to rise, leading to its evaporation, decomposition or stripping.
The following are several types of laser cleaning:
1. Laser dry cleaning
The workpiece is directly cleaned by pulsed laser irradiation, causing the contaminants on the substrate or surface to absorb energy and increase in temperature, resulting in thermal expansion or thermal vibration of the substrate, and thus separating the two. This process can be roughly divided into two situations: one is that surface contaminants absorb laser expansion; Another type is that the substrate absorbs laser to generate thermal vibration. This method does not require the use of additional chemical reagents or liquid media, and thus is called "dry".
2. Laser wet cleaning
Before the pulsed laser irradiates the workpiece to be washed, a liquid film is pre-coated on the surface first. Under the action of laser, the temperature of the liquid film rises rapidly and vaporizes. At the moment of vaporization, shock waves are generated, acting on the pollutant particles and causing them to fall off from the substrate. This method requires that the substrate and the liquid film do not react, thus limiting the range of applicable materials.
3. Laser plasma shock wave cleaning
During the laser irradiation process, it breaks through the air medium to generate spherical plasma shock waves. The shock waves act on the surface of the substrate to be cleaned and release energy to remove contaminants. Since the laser does not act directly on the substrate, it will not cause damage to the substrate. This technology can clean particulate contaminants with diameters of tens of nanometers and is not limited by the wavelength of the laser.
4. Laser + inert gas-assisted cleaning
While the laser is radiating, inert gases (such as argon or nitrogen) are blown towards the surface of the substrate. When dirt is stripped off the surface, it will be immediately blown away by gas to prevent the surface from being re-contaminated and oxidized. This method helps to improve the cleaning efficiency and ensure the surface quality after cleaning
Laser can clean the following materials:
Stubborn oxides and rust
Rust: The iron oxide on the surface of steel is one of the most effective targets for laser cleaning. Whether it is rust on large ships, bridge steel structures, heavy machinery, or precision bearings and molds, lasers can efficiently remove it, restore the original color of the metal, and provide a perfect base for subsequent anti-corrosion treatments (such as spraying and electroplating).
Non-ferrous metal oxide layers: The oxide film on the surface of aluminum alloys and the oxide layer (black spots, green rust) on copper materials can also be precisely removed, and are widely used in aerospace components, heat sinks, electronic components and other fields.
Oil stains, grease and chemical residues
All kinds of organic pollutants such as lubricating oils, cutting fluids, anti-rust oils and fingerprints are rapidly decomposed and volatilized under the action of lasers. This is crucial for surfaces that require absolute cleanliness, such as engine parts, precision gears, and semiconductor wafers.
Various coatings and plating layers
Paints and coatings: Old paint for aircraft skins, ship paint, coatings for automotive parts, exterior wall coatings for buildings, etc. Laser can peel off layer by layer or as a whole, with efficiency far exceeding traditional grinding, and there is no dust hazard.
Electroplating layer/thermal spray coating: When local repair or removal of poor coatings (such as chromium, nickel, zinc) is required, laser can achieve precise and targeted removal without damaging the underlying substrate.
Polymer coatings: such as insulating varnish, rubber coatings, etc.
Metal processing residues
Welding residues: welding slag, spatter, and oxide color (the colored oxide layer after TIG/TIG welding) are the challenges in post-welding treatment. Laser cleaning can instantly remove these flaws, enhance the quality and aesthetic appearance of weld seams, and is an ideal choice for post-treatment of high-end welding, such as pressure vessels and nuclear facility pipelines.
Release agent/mold release agent: The mold release agent remaining on the mold or workpiece after casting or molding can be thoroughly removed by laser, ensuring the quality of subsequent processes (such as bonding and spraying).
Sintering residue: In powder metallurgy or 3D printed metal parts, remove unmelted metal powder particles.
Particulate pollutants and attachments:
Dust, carbon deposits, loose particles and other substances adhering to the surface of metals or non-metals can be easily blown clean by laser. It is often used for cleaning optical lenses, precision instruments and the surfaces of artworks.
Restoration of cultural relics
For the protection of historical buildings, sculptures and artworks, laser cleaning can precisely remove surface deposits without damaging the base material, making it an important tool for cultural relic conservation
Laser cleaning, this intangible "eraser of light", with its precise, efficient, environmentally friendly and non-destructive characteristics, is redefining the concept of "cleaning" in an unprecedented way. From thick industrial rust to delicate cultural relic dust, from stubborn aircraft skin paint to precise electronic component oil stains, its all-powerful cleaning ability is profoundly transforming the face of numerous industries. With the continuous advancement of technology and the constant optimization of costs, laser cleaning is bound to become an indispensable core technology in high-end manufacturing, green maintenance and cultural heritage protection, making "as clean as new" a reality in a smarter and more sustainable way.