Reserach On Laser Cleaning Technique Of Resin Matrix Composites Coating

Resin matrix composites are gaining industrial attention as their outstanding mechanical properties stand to satisfy market demand in a wide spectrum of industrial applications ranging from the fabrication of aircraft components and structures in the aerospace industry to prosthetics of artificial limbs in the medical sector.In this paper,the surface coating of resin matrix composites was studied by fiber laser.The cleaning effect of laser cleaning parameters on carbon fiber,single-layer epoxy coating and doublelayer polyurethane-epoxy coating were studied by single-factor and orthogonal experiments.The effects of temperature,surface roughness,cleaning number and cleaning order on the removal of resin coating were studied.With the help of SEM,XPS,XRD and other techniques,the surface morphology and composition distribution of coating after cleaning could be studied.The results showed that:The particles of carbon fiber surface could be removed by fiber laser.Compared with the surface morphology of carbon fiber treated at 400 ? for one hour,the surface of carbon fiber treated by laser cleaning was brighter and the residual particulate matter was less.When cleaning the surface of carbon fiber by laser cleaning,the cleaning distance,cleaning frequency,cleaning speed,cleaning power and other factors would affect the cleaning effect.In the process of resin coating cleaning,the CO2 laser could only remove part of the coating.In the use of laser fiber,it was found that the control laser cleaning parameters could make the coating successive and layer by layer ablation.However,the thickness of the coating would vary with the cleaning parameters.For the thinner single-layer epoxy coating,the coating composition and structure were relatively close.Under the appropriate laser parameters,the thickness of the coating was linearly related to the laser energy density.In the process of the removal of monolayer coating,the coating thickness reached the maximum at 5? due to the change of intermolecular force.In the study of 100?m doublelayer polyurethane-epoxy coating cleaning,it was found that laser cleaning could remove the coating and got the clean carbon fiber surface.The surface roughness of the original coating and the light absorption rate were small.After laser treatment,the surface roughness of the coating increased,and the optical absorption rate became larger.Although the total energy of laser was equal,the cleaning order would also result in different cleaning effect when two different parameters were used to clean.Using high energy and low energy sequential cleaning would cause the first high energy could not be fully absorbed by coating.But the sequential cleaning with low energy and high energy was helpful for the second high energy to be fully absorbed by the coarse coated surface.During the cleaning process of medium or low energy density parameter,the surface roughness of the coating decreased with the cleaning process.At the same time,with the increase of the thickness of resin cleaning and the cleaning by the same parameter,the coating removal thickness gradually decreased.The study showed that 100?m doublelayer polyurethane-epoxy coating was easier to remove than 30?m single-layer epoxy coating.After the doublelayer polyurethane-epoxy coating was removed,the carbon fiber surface was better,and the coating was removed more cleanly.The elements of the doublelayer polyurethane-epoxy coating on the surface and the cleaning of 68?m had little change,but the combination of each element had changed.