With the rapid development of laser cleaning technology, new directions and trends are emerging in the field.
Among them, laser composite cleaning technology is a direction with great potential and prospect: it can double or triple the cleaning efficiency on the basis of the same price.
1. What is compound laser cleaning
As we all know, in the high-end cleaning market, the efficiency of laser cleaning will be lower than that of traditional cleaning methods at the same cost.
For example, in the paint removal work of ship overhaul, the area of ship side paint is very large, some are cleaned by chemical cleaning, some are cleaned by high-pressure water, and many shipyards will propose to use laser cleaning, but the laser cleaning is limited by power, and the cleaning area of thick paint layer per unit time cannot meet the requirements of shipyards in terms of efficiency.
Of course, technically speaking, simply to improve efficiency, it can be achieved through simple superposition power;
However, after the power is increased in this way, the cost is also increased dozens or even hundreds of times, which has no cost performance.
This means that efficient ship laser cleaning can only stay in theory, but can not enter the industrial application.
At present, the power of foreign pure pulse laser can reach 5000W, but it is not imported into China due to the technical blockade.
The maximum power of domestic pulse laser is only 1000W, and 2000W pure pulse laser is still in the commissioning stage and is not stable in use.
The compound laser cleaning technology is to realize the efficiency of 1000W pure pulse laser cleaning machine by 4000W continuous + 500W pulse, and the efficiency of 2000W pulse cleaning machine by 6000W continuous + 1000W pulse.
On the basis of the same price, the cleaning efficiency will be increased by 2-3 times through process improvement.
The utility model has the advantages of improving the cleaning quality, increasing the cleaning efficiency, stabilizing the cleaning process, being suitable for the cleaning of highly reflective materials, and avoiding the disadvantages and shortcomings of single cleaning.
At present, there is no domestic laser pulse cleaning equipment with a maximum power of 2000W, so it can be said that there is no domestic laser pulse cleaning equipment with a maximum power of 6000W.
2. Principle of laser combined cleaning
The principle of laser composite cleaning mainly uses semiconductor continuous laser as heat conduction output to make the attachment to be cleaned absorb energy to produce gasification and plasma cloud, and form thermal expansion pressure between metal materials and attachments to reduce the bonding force between the two layers.
When the high-energy pulsed laser beam is output by the pulsed laser, the vibration shock wave will make the attachment with weak adhesion directly separate from the metal surface, so as to realize the rapid laser cleaning.
The application of this technology covers ships, auto repair, rubber molds, high-end machine tools, tracks and environmental protection.
It can remove resin, paint, oil stain, stain, dirt, rust, coating, coating and oxide layer on the surface of objects.
The advantage of laser combined cleaning technology is not only the superposition of two lasers, but also the utilization rate of energy is far greater than the simple addition of two heat sources.
In the laser cleaning of thick coating materials, due to the large output of single laser multi pulse energy and the high cost of high-power pulse laser, the laser cleaning of thick coating materials is limited.
The composite cleaning of pulse laser and semiconductor laser can quickly and effectively improve the cleaning quality, and the substrate is not easy to cause damage.
In the laser cleaning of high reflective materials such as aluminum alloy, a single laser has the problem of high reflectivity.
However, the combined cleaning of pulse laser and semiconductor laser increases the energy absorption rate of oxide layer on the metal surface due to the thermal conductivity transmission of semiconductor laser, so that the pulse laser beam can peel off the oxide layer faster, so as to improve the removal efficiency more effectively.
3. Practical application cases
The wheel set is the part of the rolling stock in contact with the steel rail, which is composed of the left and right wheels firmly pressed on the same axle.
The function of wheel set is to ensure the operation and steering of locomotive and vehicle on the steel rail, bear all static and dynamic loads from locomotive and vehicle, transfer them to the steel rail, and transfer the load caused by line irregularity to all parts of locomotive and vehicle.
For high-speed rail cars, the wheels and axles are made of carbon steel without alloy elements, which often becomes the cause of cracks and brittle fracture.
Therefore, the high-speed railway needs to be overhauled after running for a period of time.
Before maintenance, the coating on the wheel axle and spoke needs to be completely stripped off.
The coating is 150-250μm epoxy resin coating material.
The traditional method is to use steel wire brush for grinding.
Although this method can peel off the coating, it is very inefficient, and the labor intensity of operators is very high.
It will also damage the surface of wheel set, so as to affect the next flaw detection.
Laser cleaning technology can effectively remove the paint layer on the wheel set surface, but the efficiency is low.
In the case of thick coating, the cleaning speed is slow and has great limitations.
While the composite laser cleaning technology can control the cleaning time of each wheel set within 8 minutes, and the cleaning efficiency reaches Sa3 (the highest cleaning standard) without damaging the substrate.
4. Manufacturers of compound laser cleaning equipment
Due to the high requirements of the R & D team for the process technology and R & D difficulty required for composite laser cleaning, there are very few product manufacturers that can operate stably in the market. If you are interested in laser cleaning machine, you can contact us.