Mechanism And Experiment Study Of Paint Layer Cleaning Based On Abrasive Water Jet Technology

Remanufacturing is an important means to realize the sustainable manufacturing. It plays an important role in promoting the development of circular economy. Remanufacturing cleaning is an important link in the remanufacturing, and it is the premise of remanufacturcd components for subsequent detection and repair. Remanufacturing cleaning quality directly determines the quality of repair, thus affecting the remanufacturing product life span. Remanufacturing cleaning technology is facing many challenges. In order to realize the green cleaning development goals, it’s necessary to improve cleaning efficiency, and it is also needed to reduce cleaning cost and reduce the pollution of the environment. Because of its many advantages of high cost and low efficiency, abrasive water jet cleaning has been widely used in remanufacturing. However, due to the lack of the mechanism of removal of the dirt on the abrasive water jet cleaning, we often need a large number of experiments to optimize the cleaning parameters for different cleaning objects. According to this situation, we study the removal mechanism in abrasive water jet cleaning for paint coating, which will provide a theoretical basis for the optimization of the cleaning parameters.We established a three-dimensional crack model for paint coating. In this model, there will form channel crack, lateral crack and interface crack in paint coating. Thus, the paint layer can be removed. We set up the experiment platform of single particle shotting, and make experiments to proving the formation of three-dimensional crack. Using the theory of stress wave propagation, we establish a model of the formation and extension of three-dimensional crack in paint coating. We make experiments with static hardness experimental head and single particle to verify time-properties of the formation of three-dimensional crack. We verify the formation and propagation of stress wave in the process of abrasive particle impact by an experiment of capturing the stress waves, which verify the formation of stress and based on the theory of wave propagation model of crack in the end. At the same time, we also study the plastic deformation damage and thermal damage of body under impact.We put forward the factors of abrasive water jet cleaning comprehensively. We studied the effect of five single factors, namely pressure, particle size, coating temperature, the thickness of the paint layer and the substrate, of three-dimensional crack formation in paint coating by the experiment of a single particle impact. We also study the damage to the substrate under different experimental conditions. All of this provide a theoretical basis for the optimizing of parameters in abrasive water jet cleaning.In order to improve the cleaning efficiency, we study a composite cleaning method in which we use abrasive water jet to cleaning the paint coating after it been pre-treated by SCCO2. There will form cracks in the paint coating after SCCO2 pre-treatment under the influence of bubble nucleation expansion effect and temperature effect of SCCO2. After the paint coating been pre-treated, we use single particle to impact it to investigate the formation of three-dimensional crack different pre-treatment condition. We also study the effect of different impact conditions on the removal of paint coating, which will provide a theoretical basis for the selection of parameters in abrasive water jet cleaning. In the end, we clean the paint coating using abrasive water jet cleaning method to study the effects of different pre-treatment conditions on the cleaning efficiency of composite cleaning method. At last,we get the optimal SCCO2 pre-treatment conditions.