Views: 0 Author: HanTenCNC Publish Time: 2021-10-17 Origin: Site
Laser cleaning technology uses high-frequency high-energy laser pulses to irradiate the surface of the workpiece. The coating layer can instantly absorb the focused laser energy, so that the oil, rust or coating on the surface can be evaporated or peeled off instantly, and the surface attachments or surface coating can be effectively removed at a high speed. The cleaning method is very short, and the laser pulse with a short action time will not damage the metal substrate under the appropriate parameters.
The cleaning process of pulsed Nd:YAG laser relies on the characteristics of the light pulse generated by the laser, based on the photophysical reaction caused by the interaction between the high-intensity beam, the short-pulse laser, and the pollution layer.
1. The beam emitted by the laser is absorbed by the pollution layer on the surface to be treated;
2. The absorption of large energy forms a rapidly expanding plasma (a highly ionized unstable gas), which produces shock waves;
3. The shock wave turns pollutants into fragments and is removed;
4. The light pulse width must be short enough to avoid heat accumulation that damages the surface to be processed;
5. Experiments show that when there are oxides on the metal surface, plasma is generated on the metal surface.
Plasma is only generated when the energy density is higher than the threshold, which depends on the contamination layer or oxide layer being removed. This threshold effect is very important for effective cleaning while ensuring the safety of the base material. There is a second threshold for the appearance of plasma. If the energy density exceeds this threshold, the base material will be destroyed. In order to perform effective cleaning under the premise of ensuring the safety of the base material, the laser parameters must be adjusted according to the situation so that the energy density of the light pulse is strictly between the two thresholds.
Nd: YAG devices have been widely used in material processing. In addition to laser drilling, welding, heat treatment, marking, writing, dynamic balancing and other processing applications, it can also be widely used in the field of micro processing. Especially the processing of large-scale integrated circuits has shown its unique advantages.