Technical Study On Paint Removal Of Remanufacturing Parts By Wet Shot Peening Cleaning

Recycling and remanufacturing end-of-life products are important means to achieve sustainable manufacturing,which can greatly reduce energy consumption and environmental pollution in the production process.Remanufacturing cleaning is a particularly essential procedure,and the cleaning quality affects the subsequent detection and repair process directly.Greeness and high efficiency of cleaning process are the main challenge of remanufacturing cleaning technology.Wet shot peening technology is a combination of dry shot peening and water jet.It is widely used in remanufacturing cleaning because of its advantages of friendly environment,low cleaning cost and high cleaning efficiency.In this paper,wet shot peening technology was studied to remove the paint contaminant on the surface of remanufactured parts.The main research work was summarized as follows:Firstly,the controlled experimental study was carried out on the effect of wet shot peening technology.The experimental phenomena was analyzed and the mechanism of removing paint by wet shot peening was explained by the existing theory.Based on the research results of the research group,the material,micro morphology and the combination of the paint on the surface of the parts and the matrix were analyzed.The experimental samples were prepared by spraying acrylic polyurethane paint on Q345C,which is a common material of engineering machinery.An experimental platform was built to carry out the contrrolled experiments of dry,wet shot peening and pure water jet cleaning.The differences in the cleaning ability,cleaning efficiency and the influence of cleaning process on the surface of the substrate by different technologies were analyzed in order to explore the characteristics of wet shot peening technology.Based on the experimental results and the existing theories,the mechanism of removing paint layer by wet shot peening was explained.The impact and grinding action of shot peening as well as the impact of water jet and the crack generation and expansion caused by water wedge are the main reasons for the removal of paint layer.Then,based on the orthogonal experiment method,the wet shot peening process parameters of Q345C material surface paint cleaning removal effect were studied.Both the cleaning efficiency and the effect of cleaning on the surface of substrate were considered.The best combination of process parameters including water pressure of power source,abrasive feed rate condition and cleaning stand-off distance was obtained.The results showed that the water pressure of power source has the greatest influence on the cleaning effect,while the impact of wet shot peening jet on the surface of the substrate after cleaning has little difference under different parameter combinations.The experimental results provide a parameter guidance for enterprises to carry out the industrial application of wet shot peening technology.Finally,in order to explore the change law of flow field within the wet shot peening nozzle and study the motion characteristic parameters of the wet shot peening jet,the FLUENT software was used to simulate the flow field inside the nozzle.The three-phase motion law of air,water and shot peening in the nozzle under different water pressure of power source was obtained.The data of simulation results were extracted,and the functional relationship between water and shot peening velocity as well as water pressure of power source was fitted linearly.Through the conversion method,the numerical difference between the actual velocity and the simulation velocity was compared,and the accuracy of the simulation results was verified.Through the establishment of nozzle models with different structures for simulation,the position and angle parameters of shot peening and air inlet pipe were optimized,and the better nozzle structure for remanufacturing cleaning was obtained.