The bonding force between dirt and stone surface is mainly physical force and weak chemical force. Weak chemical forces include hydrogen bonds and bond energy formed by charge transfer, and physical forces include van der Waals forces (including electrostatic, induced and dispersion effects) and capillary forces. The reason why stone is more difficult to clean than other hard surface materials is that due to the large number of micro-holes in natural stone, the capillary force of micro-pores not only enhances various binding forces between dirt and stone, but also has a wrapping effect. It also makes it difficult for various cleaning external forces to work.
One is to use the difference in the absorption coefficient of the laser energy of a certain wavelength between the substrate material and the dirt attached to the surface, so that the laser energy is fully absorbed by the attached dirt, so that it is thermally expanded or vaporized, and is driven by the vapor flow formed by the vaporization. The purpose of cleaning is achieved by separating from the matrix material. The requirement is that the absorption coefficient of the matrix material to the laser energy should be small, so that the matrix material will not be damaged. Therefore, the key to achieve safe and efficient cleaning is to choose the appropriate laser wavelength and control the energy density.
The other type is the cleaning of the absorption coefficient of the laser beam between the matrix material and the surface attachment, or the surface attachment will produce toxic substances after being heated, usually by using pulsed laser shock of higher frequency and power to be cleaned. The surface of the laser beam is converted into sound waves, and the sound waves return after hitting the middle and lower hard surfaces, and the returned part interferes with the incident sound waves generated by the laser, thereby generating high-energy resonant waves, causing tiny bursts of the scale layer, resulting in crushing and easy off the surface of the matrix material.
The above is the application of laser cleaning machine in the stone industry. Laser cleaning technology mainly uses laser beam to remove the attachments on the surface of the object to be cleaned at high speed and effectively. It saves time, labor and water, and is safe and reliable. It is widely applicable and easy to automatically control. Especially for the cleaning of stone surface fine structures such as stone carvings, stone carvings, various corners, and high-end stone materials such as ancient stone cultural relics, the advantages of laser cleaning technology are unmatched by many traditional cleaning processes.