Laser technology is now prevalent in various industries, and laser cleaning technology is no exception. With increasing environmental awareness, the use of lasers to replace traditional chemical cleaning methods is becoming more and more popular. Laser cleaning equipment relies on light pulses generated by a laser. The cleaning process is based on photophysical reactions resulting from the interaction between a high-intensity light beam, short-pulse laser, and the contaminant layer.
So, how does laser cleaning equipment remove paint? To understand how laser cleaning works for paint removal, it’s essential to first understand the cleaning mechanism of laser cleaning equipment.
Paint applied to a metal surface acts as a special type of plasma, protecting the metal from corrosion and oxidation. This plasma is only generated when the energy density exceeds a certain threshold. The specific threshold depends on the contaminant or oxide layer being removed. This threshold effect is crucial for effective cleaning while ensuring the safety of the underlying substrate material. A second threshold exists for plasma formation. If the energy density exceeds this second threshold, the substrate material will be damaged. To ensure effective cleaning without harming the base material, laser parameters must be carefully adjusted to keep the energy density of the light pulses strictly between these two thresholds.
Each laser pulse removes a certain thickness of the contaminant layer. If the paint layer is thick, multiple pulses are needed for complete removal. The number of pulses required to clean a surface depends on the degree of surface contamination. A significant result of these two thresholds is the self-limiting nature of the cleaning process. Light pulses with an energy density above the first threshold will continue to remove contaminants until the base material is reached. However, because the energy density is below the damage threshold of the base material, the substrate remains undamaged. This is a core principle of effective laser cleaning.
In summary, when using laser cleaning equipment to remove paint from metal surfaces, precise control of the thresholds is paramount. Effective laser cleaning is only achieved when the thresholds are set within the appropriate range. If the required threshold range cannot be achieved, it indicates that the laser cleaning equipment is not suitable for the specific task. This is one reason why laser cleaning equipment is not a universal solution. However, with continued advances in laser research and development, the capabilities of laser cleaning equipment are becoming increasingly powerful, and the goal of being able to clean almost anything may be achievable in the future.