Pulsed lasers are usually used for surface cleaning. On the one hand, they differ in nominal power (usually from 50 to 1000W), but the energy of the pulse is also an important parameter. This must overcome the activation energy necessary to break the chemical bonds in the molecules of the material to be removed and to vaporize/sublimate it. The energy of the pulses for lasers of lower ranges is usually around 1 mJ. Such lasers are used, for example, for cleaning museum exhibits. The middle class of lasers has a pulse power of around 10 mJ. A higher category of lasers suitable for industrial applications has a pulse energy of even 100 mJ. In addition to the resonator itself, i.e. its own source of laser radiation, the optical apparatus, optical fiber, mirror system oscillating the laser beam onto the surface to be cleaned, etc. are very important. A quality pulsed laser with a lower power can be significantly more effective for cleaning than a cheap product with paper-sized power.

As with most electronic and optical devices, the difference between cheap products from the East and products from reputable manufacturers is both price and quality. Manufacturers from East Asia often use continuous radiation sources for cleaning lasers. With those, it is not possible to set basic parameters such as pulse energy, its length and frequency. Such lasers usually have a relatively high power, but it is not possible to adapt the parameters to the given cleaning process. It's basically like removing dirt with a hacksaw - it works, but the resulting surface matches it.

Yes, and very efficiently. Soot, flue gas and carbon very well absorb the light of the most commonly used wavelength of cleaning lasers 1064nm and very willingly change to gaseous form. Surfaces such as wood or painted surfaces can also be cleaned excellently with a laser. Lasers can be used to remove, for example, flue gases and soot from facades and walls, and to remove the consequences of a fire. Laser removal of exhaust fumes in engines and exhaust systems is also effective.

Laser cleaning is non-contact. As a rule, there is no damage to the cleaned surface, however, the correct setting of the laser parameters is important. E.g. for the cleaning of historical objects of high value, such a setup may take longer than the cleaning itself. Special care should be taken when cleaning wood and materials with low thermal conductivity . Secondary heating and subsequent expansion must be taken into account when cleaning metal objects. However, the risk of damage is minimal compared to other cleaning methods, e.g. there is practically no wear and tear when cleaning molds, even when cleaning is repeated many times . In the same way, polished, brushed or otherwise structured surfaces are not damaged. Laser cleaning is also very well used, for example, in the cleaning of steel surfaces in tokamaks and nuclear power plants , where the demands for surface preservation are extreme.

The price of laser cleaning is usually based on hourly rates. The purchase costs of cleaning lasers (for powerful devices for industrial applications in the order of many millions) are largely reflected in the price. On the other hand, laser cleaning does not pollute the surroundings, it is often not necessary to dismantle electrical connectors, bearings and other mechanical components, upholstery, etc. The resulting price of cleaning can thus often be lower than with other methods.

Surfaces made of various metals, steel, cast iron, stainless steel, aluminum, bronze , etc., are most often cleaned with a laser . Plated surfaces can also be cleaned with a laser. Here, it is necessary to set the appropriate parameters of the pulse laser to avoid damage, however, cleaning is also very effective here. They are very good at cleaning inorganic building materials such as bricks, concrete, stone and glass (even through glass) or paving . Cleaning wood is more complicated. It is necessary to take into account its low thermal conductivity and thermal stability, however, laser cleaning of wood is advantageous in a number of applications. For example, we tested the removal of fire-resistant varnishes, which are otherwise very difficult to sand. You can easily clean surfaces where different materials are next to each other, e.g. steel with duralumin (alternators, starters, pumps, generators). With a suitable setting, it is not necessary to dismantle and disassemble the cleaned objects, the sensitively set laser will not damage electrical connectors, guffers, bearings , etc.

Laser cleaning is based on the so-called laser ablation, when the vast majority of the removed material (usually more than 90%) goes into the gas phase, essentially evaporates. One of the basic advantages of laser cleaning is that there is no contamination of the surroundings with abrasive dust, as with blasting, or with liquid, as with pressure water washing. The laser can be used to clean interiors, facades or structures in public (due to health and safety, it is only necessary to avoid the risk of exposure to the laser beam), in the immediate vicinity of generators, hydraulic equipment, etc. An absolutely minimal amount of secondary waste is created, there is no spread of e.g. microplastics or particles from coatings containing heavy metals. Laser cleaning is very suitable for removing dirt near waterways and sources of drinking water .

A pulsed laser can be used to remove rust and other corrosion products very effectively, or most oxides and inorganic complexes of metals such as aluminum, copper, tin, titanium, etc. It is very easy to clean surfaces from grease with a laser, i.e. from different oils , from petroleum jelly , temporary anti-corrosion oils and waxes are quite often removed. The laser removes oil product residues very well. The laser-degreased surface is perfectly prepared, for example, for welding or for applying new paint. Another application of cleaning lasers is the removal of paints and varnishes , where the effectiveness is different, it is usually necessary to test the laser for the given application. Dark colors go better, colorless varnishes go relatively well. If safety rules are followed , paints containing heavy metals such as sulfur can be effectively removed. There are also a number of special industrial applications, we removed, for example, deposits formed by nickel and chromium carbides from glass tubes, inorganic deposits in furnaces, komaxite chambers, vacuum chambers, graphite, polyurethane (PUR) foam , polyamide (PA) surfaces from sliding bushings, etc. In combination with mechanical cleaning, we successfully tested the removal of fire-resistant varnishes . The laser can be used to decontaminate surfaces from biologically active substances such as drugs, or to remove dust in clean rooms.