Technical Study On Laser Cleaning Process Of Epoxy Resin Paint On Aluminum Alloy Surface

Compared with the traditional method of paint removal,the laser cleaning techniques have the advantages of no direct contact,environmental friendly,high cleaning efficiency and low operating cost,which makes laser cleaning have great development in the field of paint removal.The laser ablation is one method to remove the paint,and the substrate will be damaged during the ablation.The thermal stress is another method to remove the paint,but this method is still in the experimental verification phase.Aluminum alloy is widely used in aviation,construction and automobiles due to its huge output and unique properties.The research of paint removal on aluminum alloy surface is of great significance,and also has good reference in the removal of paint on other metal surfaces.In this thesis,the removing process of the epoxy resin paint on aluminum alloy surface with thermal stress is studied.The simulation code and experimental results are discussed in this thesis.Firstly,the theoretical basis of laser cleaning based on the interaction between light and substance is analyzed,and the theoretical code of epoxy resin paint on aluminum alloy surface is established.Combined the theoretical model,heat conduction equation and physical properties of the material,the temperature distribution of the model is simulated under the actual environment.The theoretical cleaning threshold is obtained by considering the thermal stress caused by laser irradiation and the adhesion force between the substrate and the paint.The laser paint removal experimental platform consisting of a fiber laser,a beam control part,a sample platform and computer terminal is established,and the laser cleaning process of epoxy resin paint on aluminum alloy surface is studied.The actual cleaning threshold of 0.255 J/cm2 is obtained by the experiment with the overlap of 0%,which is consistent with the simulation threshold of 0.240 J/cm2.In order to verify the applicability of the model,the cleaning process of epoxy resin paint on the iron metal substrate is tested.It is found that the actual cleaning threshold of the iron substrate is 0.238 J/cm2,which is consistent with the simulation result of 0.233 J/cm2.The influence of cleaning effect with the laser fluence,pulse repetition rate,pulse duration,scanning speed and scanning step is studied with microscopy and image processing technology,and the optimization of process parameters is obtained on the removal of epoxy paint on aluminum alloy surface.Compared with laser ablation,the cleaning method used in this thesis has a higher cleaning speed,lower cleaning threshold and no damage on substrate,which has potential application value for efficient and non-destructive removal of aluminum alloy surface paint.