Coating Paint Removel By Laser Cleaning Machine

Coating Paint Removel By Laser Cleaning Machine

The process of laser cleaning depends 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 contamination layer. Its physical principle can be summarized as follows:

a) The beam emitted by the laser is absorbed by the contamination layer on the surface to be treated.

b) The absorption of large energy forms a rapidly expanding plasma (highly ionized unstable gas), which produces shock waves.

c) The shock wave breaks the contaminants into fragments and is ejected.

d) The light pulse width must be short enough to avoid heat build-up that would damage the treated surface.

e) Experiments show that plasma is generated on the metal surface when there are oxides on the metal surface.

Plasma is only generated at energy densities above a threshold, which depends on the contamination or oxide layers being removed. This threshold effect is important for effective cleaning while keeping the substrate material safe. There is also a second threshold for the emergence of plasma. If the energy density exceeds this threshold, the substrate material will be destroyed. In order to carry out effective cleaning under the premise of ensuring the safety of the substrate 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.

Each laser pulse removes a certain thickness of contamination layer. If the contamination layer is thicker, multiple pulses are required for cleaning. The number of pulses required to clean a surface depends on the degree of contamination of the surface. An important consequence of the two thresholds is the self-control of the cleaning. Light pulses with an fluence above the first threshold will reject the contaminants until they reach the substrate material. However, since its energy density is below the damage threshold of the substrate material, the substrate will not be damaged.