The discovery of laser cleaning technology was an unexpected process. In 1964, Dr. Xiao Luo, an American, inadvertently irradiated a piece of paper with a laser in the laboratory, and found that the laser could quickly remove the ink on the paper without damaging the paper, and put forward the concept of "laser erase" for the first time.
In 1969, the American Berdal used a pulsed laser to remove oxides on the surface of nickel, and studies showed that under the appropriate laser parameters, oxides and sulfides could be cleaned without damage to the metal surface, and the cleaning effect was excellent. After repeated tests, Professor Berdal found that in order to achieve a good cleaning effect, the selection of laser wavelength and the control of laser energy density are the key. Only a specific laser wavelength and a suitable laser energy density can achieve oxide removal without damaging the substrate. For the first time, Berdal proposed the concept of "laser cleaning".
It has been 59 years since the discovery of laser cleaning, and the development of the laser cleaning industry is still at the level of primary school students, far from being mature, and has not exerted its maximum power, the main reason is that the cost of laser cleaning is higher than that of traditional cleaning methods, and the market does not have much power to use it.
Laser cleaning was discovered by accident, people did not know its principle at that time, and for a long time, no one said its principle clearly, today we will analyze its principle.
At that time, the laser used by the American scientist Dr. Xiao was a semiconductor laser, with a laser wavelength of 1064nm, which is similar to the popular fiber laser, which is currently the most widely used laser, laser marking, laser welding, laser cutting all use fiber lasers, and even now laser rust removal, laser cleaning molds, laser cleaning oxide layers, plating, etc. The fiber laser mainly reacts to the conductor material, and the insulator material has only a very low absorption rate for it. Dr. Xiao accidentally irradiated the ink on the paper with a laser with a wavelength of 1064nm and was removed, but the paper was intact, because the raw material of the ink was graphite, which belongs to the conductor material, and it had a high laser absorption rate of this wavelength, and when the ink absorbed the laser energy, it instantly vaporized and disappeared, and the paper was an insulator material, which almost did not absorb the laser of this wavelength, so it was intact.
Therefore, laser cleaning is a method that uses the characteristics of different wavelengths of laser light to react to different materials to remove specific contaminants.