Principle of laser paint removal of aircraft skin
The principle of laser cleaning is to use the characteristics of laser beam, such as large energy density, controllable direction and strong convergence ability, to destroy the binding force between pollutants and matrix, or to make the pollutants directly gasify, so as to reduce the binding strength between pollutants and matrix, so as to achieve the effect of cleaning the work-piece surface. The schematic diagram of laser cleaning is shown in the figure. When the pollutant on the surface of the work-piece absorbs the laser energy, it quickly vaporizes or instantly expands to overcome the force between the pollutant and the substrate surface. Due to the increase of heating energy, the pollutant particles will vibrate and fall off from the substrate surface.
The whole process of laser cleaning can be divided into four stages, namely, laser vaporization and decomposition, laser stripping, thermal expansion of pollutant particles, vibration of substrate surface and pollutant separation.
Advantages of laser cleaning technology in aircraft skin paint stripping
The safety requirements of aircraft are almost strict. Therefore, whether production or maintenance, the improvement of each process, safety should be regarded as the primary factor!
In order to ensure the safety of the aircraft, the aircraft needs to be repainted every five years or so. In the process of aircraft maintenance, the paint on the surface of the aircraft must be removed. At the same time, the corrosion defects and fatigue cracks on the surface of the aircraft skin must be inspected to avoid flight accidents. Most importantly, in the process of removing the paint from the surface of aircraft skin, special attention should be paid to the paint removal process, which must ensure that the substrate will not be damaged.
The paint remover used in the past not only pollutes the environment, damages the health of operators, but also costs a lot. Compared with traditional processing methods, laser cleaning technology has many advantages, such as no pollution, no damage, no stress, easy to realize automation and so on. It is very safe to clean precision workpieces or parts, and can ensure its accuracy. It has a great application prospect in aircraft skin paint stripping in aerospace field.
Application of laser cleaning technology in aircraft skin paint stripping
In order to confirm whether the laser cleaning technology will affect the paint removal effect of aircraft skin, chihalo laboratory has taken samples from real aircraft skin and carried out paint removal by laser with repetition rate of 50KHz and energy density of 83j / cm2. The tensile test data after paint removal show that the strength failure of the sample will not be caused by laser irradiation.
In addition, chihalo used a continuous CO2 laser to remove the paint from the simulated aircraft skin sample. The laser power was 30W / mm2, and the old paint could be removed at a scanning speed of 400mm / min without damage to the substrate. Compared with the matrix, the tensile strength, fatigue strength and Vickers hardness of the aircraft skin after depainting have no change, but the corrosion resistance has increased; The higher the laser energy density is, the narrower the pulse width is, and the better the paint removal is. At present, the old paint layer with a thickness of 1 mm and an area of 36 M2 can be completely removed within 1 hour by laser cleaning, and the skin of a Boeing 737 can be completely removed within 48 hours.
In the application of laser cleaning technology, what should we pay attention to?
In the application of laser cleaning technology, we need to pay attention to the laser cleaning threshold of the object to be cleaned, select the appropriate laser wavelength, and then achieve the best cleaning effect. Laser cleaning can not only change the grain structure and orientation of the substrate surface without damaging the substrate surface, but also control the surface roughness of the substrate, so as to enhance the comprehensive performance of the substrate surface. The cleaning effect is mainly affected by the beam characteristics, the physical parameters of substrate and dirt materials, and the absorption capacity of dirt to the beam energy.
Chihalo, the biggest OEM Laser Cleaner Manufacturer