Electrophoretic coating technical

Electrophoretic coating technology, also known as the electrodeposition coating. Is a method of film formation, application of waterborne coatings forelectrophoretic coating special, it is provided with a conductive (anode or cathode) coated objects immersed in the electrophoresis tank solution,electrode is arranged in the groove of the corresponding electrophoresis(anode or cathode), in between the two poles of DC electricity, in coatedarticles on precipitation of uniform, a method of coating and water insolublecoating.

(1) electrophoresis coating general metal surface, its technological process is:pre cleaning, degreasing, water washing, on-line, rust, water washing,neutralization, washing, water washing, phosphating, passivation,electrophoretic coating, trough cleaning, washing, drying, offline ultrafiltration.

(2) is the substrate and pretreatment coated on the electrophoretic coatinghas great effect. Castings generally blasting or shot peening derusting, to remove the surface dust with cotton yarn, 80# ~ 120# sandpaper to remove surface residual impurities such as steel. Iron and steel surface by degreasing and derusting treatment, high demands on the surface, phosphating and passivation surface treatment. Ferrous metal workpiece must be phosphatingat the anode electrophoresis paint film before, otherwise the worse corrosion resistance. Phosphating treatment, the general choice of zinc salt phosphating film, thickness of about 1 ~ 2 m, the requirements of the phosphating film is fine and uniform crystal.

(3) in the filtration system, generally use the single filter, the filter for bag type structure, the diameter of 25 to 75 M. Electrophoretic paint by vertical pump tofilter and filter. Considered from the factors change cycle and film quality,diameter of 50 mu m filter bags are the best, it can not only meet the filmquality requirements, and resolving the problem of blocking the filter bag.

(4) the size of system of circulating amount of electrophoresis coating, directly affect the quality of the bath stability and coating. Increase the recyclingamount, precipitation and bubble bath decreased; but the bath ageingaccelerates, the energy consumption increases, the stability of bath solutionvariation. The number of cycles the bath control 6 ~ 8 times /h is ideal, not onlyensure that the film quality, but also to ensure the stable operation of the bath.

(5) with the extension of production time, the impedance of the anodediaphragm will increase, the working voltage effective drop. Therefore, in the production should be based on the circumstances of the loss of voltage andgradually increase the high working voltage of power supply, to compensate for the voltage drop of the anode diaphragm.

(6) concentration of impurity ions into the workpiece ultrafiltration controlsystem, ensure the quality of coating. Should pay attention to in the operation of the system, once the system is running after the continuous operation, it is strictly prohibited to intermittent operation, in order to prevent the ultrafiltration membrane dry. Dried resin and paint adhesion in ultrafiltration membrane, can not be completely cleaned, will seriously affect the ultrafiltration membranepermeability and service life. Ultrafiltration membrane water rate with therunning time of a downward trend, work for 30 to 40 days should be cleaned again, to ensure that the ultrafiltration dip and rinse required ultrafiltration water.

(7) the production process of electrophoresis coating method is applicable to a large number of pipeline. The update cycle of electrophoresis tank solutionshould be within 3 months. With an annual output of 300000 copies of rimelectrophoresis production line as an example, the scientific management of the bath is very important, regular testing of various parameters on the bath,and according to the detection results of adjustment and replacement of the bath. Generally follow the following frequency measurement bath parameters: electrophoretic liquid, ultra filter and ultrafiltration cleaning fluid, Yin (Yang)polar circulation lotion, deionized cleaning solution pH, solids content andconductivity once a day; pigment / binder ratio, laboratory organic solventcontent, small cell test 2 times a week.

(8) on the film quality management, should always check the homogeneity offilm and film thickness, appearance should not have a pinhole, sagging,orange peel, wrinkles, physical and chemical indicators regularly check thecoating adhesion, corrosion resistance etc.. The inspection cycle according to the manufacturer's inspection standards, generally are required to test each batch.

Using electrophoresis painting equipment and water paint, marking a significant progress of coating industry.

The construction speed of coating electrophoresis quickly, and can realize the mechanization and automation of continuous operation, reducing the labor intensity, uniform paint film, strong adhesion, coating method on the general is not easy to apply to or coated with bad parts, as mentioned before thereinforcement plate welding joint can obtain a uniform flat, smooth film. Paintutilization rate of up to 90%-95%, the electrophoretic coating in water as solvent, has the advantages of incombustibility, non-toxic, convenient operation etc.. After electrophoresis after drying of the paint film, good adhesion, anti rust and its corrosion resistance, weather resistance and otherproperties are better than ordinary paint construction method and general.