Managenment Of Pretreatment And Electrophoresis Coating In Tianjin Faw Xiali Co. Ltd

Pretreatment and electrophoresis play important parts in automobile body coating. Pretreatment plays a decisive part in the quality of the coat film; and it is the precondition for the paint to exert its function. Cathode electrophoresis coating process has multiple technical parameters. So it's hard to manage. It has been the key process for controlling the quality of the products all the time.First, introduction of process layout and mechanical of pretreatment and electrophoresis process of automobile body coating.1. process layout of pretreatment and electrophoresis process 2. mechanical of pretreatment and electrophoresis process Mechanical of degreasing, surface modulation, phosphating and cathode electrophoresis are simply introduced here.(1) All kinds of oil pollution on the car body not only hinders the forming of the phosphating film, but also affects the performance of the film. It must be cleaned before coating. The main way of degreasing includes solvent-type cleaning and alkaline cleaning.(2) Surface modulation process is expressed as using surface conditioning agent to form slightly and well-distributed and compact crystallized film. Colloidal Ti–phosphate is used as the main agent here nowadays.(3) In the phosphating process, metal surface is contacted with acid solution of dihydrogen phosphate to form a stable and insoluble metallic phosphate film.(4) Electrophoresis coating is an especial way of coating. In this process, conductive matter which is to be painted is dipped in the electrophoretic paint tank as the anode (or cathode). Cathode (or anode) is set in the tank. After electrifying them for a period of time, a well-distributed and water insoluble film is obtained on the matter. In this process, the action of electrophoresis, electrolyte, electrodeposite and electroosmosis cause the form of the film.Second, process management of Tianjin Faw Xiali Automobile Co. Ltd1. The main procedure of pretreatment process.2. main parameters in pretreatment process3. The main procedure of cathode electrophoresis process.4. main parameters in cathode electrophoresis processThird, application of environment friendly led-free electrophoresis paint1. transition of environment friendly led-free electrophoresis paintBy using the dynamic and the static mixing way, we can thoroughly know the variability of the parameter of the tank and the performance of the film, so to confirm the feasibility of mixing.2. the result of mixing jobMixing job was successfully done without disturbing the workshop's normal production. The performance of the newly electrophoresis film improves a lot. It has stronger suitability to the site. And it also has lower baking temperature and heating loss. This job lasts for four and a half months from the beginning to the entire replacement of the paint. As the two paints have similar components, and the same solvent systems, they are more likely to be dissolved by each other. Abnormal deposition and particles haven't appeared on the film. The transition of the paint improves the appearance of the film. The roughness of the film has been improved. And the film becomes more smooth and delicate. It also decreases the bake temperature of the film, which saves power obviously. Now, baking temperature has been decreased for 15 Centigrade. Film can be dried well. And still matches well with middle coating. Now it is managed totally according to the rule of paint TTK-100LF.Fourth, bacteria problem of cathode of new environment friendly led-free electrophoresis tankHalf a year after using the new paint, in the latest summer, the thickness of the primer coat began to decrease. We guessed that it must because that the bacteria appeared on the cathode and reduced the effective conductive area. The appearance of bacteria caused the resistance value increasing and accordingly the current became lower. At last the film became thinner.1.strategy for the bacteria problemAccording to the content of the bacteria in the tank, we together with technologist from Tianjin Yongfu Kansai Automotive Coatings Company, made a few measures to deal with it. First we used bactericide N-75 imported from Japan to disinfect the bacteria. Then we used hydrogen peroxide solution periodically. At the same time, we cleaned the circulating line regularly. Also we fixed an ultraviolet bactericidal equipment on the deionized water equipment.1.resultBy taking such measures, we got evidently good effects. The current value recovered to the normal value. The thickness of the film comes to the normal level. We reset the parameters to the normal, And the production goes regularly. We realized that we have lacked experiences when we began to use the new environment friendly led-free electrophoresis paint. Practice has proved that we must regard equipment management the same role as the process management. So we can get good coating quality.In this thesis, pretreatment and electrophoresis process is simply introduced. Meanwhile, combining with the practical production of the workshop of Tianjin Faw Xiali Co. Ltd, the defects of the primer often seen was analyzed and been given the remedy. The transition job of the new environment friendly led-free electrophoresis paint and the bacteria problem are analyzed in detail. Hope this can be helpful to the coating industry's progress and more environment-friend.