Laser technology has a wide range of applications in many fields, such as industrial manufacturing, medicine, military, scientific exploration, business, entertainment and so on. In the 1970s and 1980s, lasers started to be used to clean the surfaces of artworks in various countries. Subsequent attempts to use for cultural relics surface debris cleaning, generally in the stone cultural relics with more. At present, many countries such as France, the United States, Britain, Greece, Italy, etc. have used laser technology in the restoration of cultural relics.
How Laser Cleaning Technology Works?
Laser cleaning machine is the use of high-energy laser beam irradiation object surface. Surface dirt, rust spots or coatings are instantly vaporized or stripped away. This results in a clean process. Lasers typically consist of three parts: a resonator, a light generator and a cooler.
The principle of operation: the laser emits a monochromatic strong, highly concentrated energy and in a single direction of the light emitted. Then connect to the laser head via the resonator lead arm or fiber optic cable and adjust the laser head to complete the cleaning. Because the laser is monochromatic and directional light radiation is very good. Therefore, it is possible to focus the beam by means of a combination of mirrors, concentrating the beam into a small area or region. Correct control of the laser beam will show the cleaning effect.
How Lasers Clean Stone Artifacts?
Because the surface of the stone artifacts dirt and stone is a combination of weak chemical and physical forces. Weak chemical forces include hydrogen bonding and bonding energy formed by charge transfer. Physical forces include van der Waals forces (electrostatic, induced and dispersive effects) and capillary forces.
In addition, stone is more difficult to clean than other materials because of the large number of micropores that exist in natural stone. The capillary force of the microporous space not only makes the various bonding between the dirt and the stone, but also the bonding force. At the same time, its wrapping effect also makes it difficult to play a role in a variety of cleaning forces.
When a laser beam hits the surface of an object, it can have at least three effects. First, it will produce mechanical resonance phenomenon on the solid surface, so that the surface layer or condensate broken off. Secondly, it will make the surface layer of dirt by the expansion and overcome the base material on the dirt particles adsorption and detach from the surface of the object. Third, in an instant so that the dirt molecules evaporate, vaporize or decompose.
Laser cleaner is the use of laser pulse vibration, thermal expansion of particles, molecular photodecomposition or phase transition of the three roles. As well as the joint action to overcome the dirt and the substrate material surface of the bonding force, so that the dirt from the surface of the object to achieve the purpose of cleaning.
