Laser ablation is the precise removal of coatings using a laser beam. When it comes into contact with the surface of the material, there is an exchange of energy, leading to the selective evaporation of various layers. Laser ablation works on the object's surface, removing material from it with minimal interference. Its level can be easily altered and regulated depending on the material, laser beam intensity, pulse length, and the wavelength of the used laser. At low laser flux, the material is heated by absorbed laser energy and evaporates or sublimates, while at high laser flux, the material is typically transformed into plasma. By choosing the power density, contaminants can be safely and precisely removed from almost any surface, including metal alloys, composites, ceramics, and even paper.
The simplest advantage of using laser ablation is the controlled removal of material from a solid surface. Very short laser pulses ensure the removal of the coating in a time frame so short that the surrounding material absorbs very little heat. An example of using this phenomenon is removing a wide range of materials such as heavy metals, paints, corrosion, grease, and industrial compounds.
Laser ablation is a much more cost-effective and environmentally friendly technique for removing coatings compared to any other abrasive or chemical methods. When using it, there's no need for abrasives, solvents, or chemicals. Compared to other types of laser cleaning processes, the fiber laser offers additional environmental benefits.
FLASER lasers offer ablation based on pulsed laser. This is an environmentally friendly process that is much gentler than the abrasive technique, and material heating is minimal.
When the laser beam contacts the material surface, there is an energy exchange between the used laser light and the material being cleaned. Laser ablation involves irradiating material surfaces with a laser pulse of appropriate energy density (power density) to selectively evaporate various layers.
A single laser radiation pulse in this device (200 W laser power) has a circular shape. Both this shape and the relatively large area hit by radiation in a single pulse allow for even power distribution. By adjusting parameters such as frequency, speed of laser beam scanning, and head feed, a uniform distribution of "spots" of successive pulses hitting one after the other can be achieved. This results in uniform cleaning of the entire surface.
Different parameter settings can achieve different effects. Laser parameters can be set so that individual pulses partially overlap (see Figure Variant B) or leave gaps between them (see Figure next to it; Variant A). Such cleaning (Variant A) leads to non-uniform development of the active surface in its microstructure. This cleaning method significantly enhances the preparedness of the cleaned surface for painting, welding, or gluing.
Laser cleaning is characterized by advantages that give this method an edge over other "traditional" cleaning and preparation methods for various surfaces. It is a method that is:
Non-invasive
There is no mechanical or chemical interaction with the cleaned substrate. Due to the advantages mentioned above, the laser cleaning method is successfully applied in heavy industry, electronics industry, aerospace industry (among others in aircraft repairs), as well as in the restoration of monuments in painting, sculpture, architecture, and technology.
Versatile
Cleaning metal, composites, and other plastics, ceramics, wood, stone, and others. There are situations where an object consists of various materials, and the application of previously used techniques becomes problematic because the different nature of each material necessitates the use of a different conservation technique.
Selective
Selective removal of individual layers from a specific surface. If the surface of an object is covered with several layers of coatings, we can successively uncover subsequent repaintings by setting the so-called threshold of laser ablation beforehand.
Environmentally Friendly
Elimination of harmful substances. The use of laser completely eliminates the formation of harmful substances, thereby reducing their destructive impact on the cleaned object. Furthermore, the laser ablation method (unlike the commonly used sandblasting method) is clean and dust-free, enabling its use practically in any conditions.