1. After the electrophoresis paint coating attached to the wet coating film groove liquid is not cleaned, drying after the coating surface to produce spots, called dry paint or paint.
the reason:
A. The time between electrophoresis and post-wash is too long.
B, 0 cleaning is not complete, after electrophoresis water washing is not
the
.
C, electrophoresis tank liquid temperature is high.
prevention and control methods:
A, the time between the coated from the electrophoresis tank to 0 cleaning should be within 1min.
B, strengthen 0 washes, so that the coating cleaning completely, including control of washing pressure and water quality.
C, properly reduce the temperature of electrophoresis paint, usually controlled at 30 degrees C.
2. Coating plaque
substrate surface pollution, after electrophoresis coating, dry paint film surface still has visible markings or map marks, this electrophoresis paint film is called coating plaque, and the difference between water marks and paint film traces is that the coating surface is still flat.
the reason:
A. The water after phosphation is not sufficient (bad).
poor quality of washing after B and phosphation.
C, the previously treated surface is contaminated again, such as sewage dripping on the surface of the pretreated work surface.
prevention and control methods:
A, strictly control the quality of washing after phosphation, check the cleaning water and cleaning equipment.
B, strengthen the control of water washing after phosphation, fresh deionized water after cleaning drip hydropower guide should not be greater than 50us/cm.
C, prevent secondary contamination of the previously treated surface, and prevent dripping on the hanger.
3. Uneven paint, rough
after drying electrophoresis paint film surface gloss, uneven lubrication, there is yin and yang surface, the damage of this electrophoresis paint film is called paint uneven or paint rough, light gloss is not good or loss of light, paint film appearance is not plump, heavy feel is not good (with the hand feel rough feeling). If the paint film lubricated with light on a vertical surface (or below the horizontal level) during electrophoresis, the electrophoresis paint film on the horizontal surface is rough and ointmentless, which is called "L" and has a poor effect.
the reason:
A, the phosphate film on the surface of the coating is unearmed and too thick, usually controlled below 3um, phosphate after the water washing is not sufficient.
B, electrophoresis paint solid content is too low, electrophoresis paint has small coagulation, insoluble particles, electrophoresis paint filtration is not good.
C, electrophoresis paint is too high.
D, electrophoretic paint mixed with imperished matter, such as impurities such as impurities mixed in, electrophoretic paint conductivity is high.
the volume content in E, electrophoresis paint is too low.
F, the flow rate of electrophoresis paint around the coating is too low.
G, electrophoresis paint temperature is low.
prevention and control methods:
A, improve the quality of phosphate, choose a fine phosphate film, strengthen the water treatment after phosphation and washing water.
B, improve the solid content of electrophoresis paint, control its range specified in the indicators, strengthen the full filtration of electrophoresis paint, especially to remove the heavy particles that can easily sink.
C, reduce the amount of color paste to reduce the color ratio of electrophoresis paint.
D, discharge ultrafiltration liquid, increase deionized water, reduce the impurity ion content and conductivity in electrophoretic paint.
E, increase solvents, increase the content of organic solvents in electrophoresis paint.
the number of cycles and stirring force of electrophoresis paint during electrophoresis by using F.
G, the temperature of electrophoresis paint strictly controlled within the range of technical indicators.
4. Poor corrosion resistance (poor resistance to salt and fog)
causes:
A, phosphate film is too thin and uneven.
B, paint liquid in too many impurity ions, when accumulated mixed into the electrophoretic paint film.
C, electrophoresis paint thickness is not enough.
D, electrophoresis after washing water with more salt.
E, electrophoresis film curing is not complete.
prevention and control methods:
A, strictly control the quality of phosphate film.
B, discharge ultrafiltration liquid to remove impurity ions.
C, increase the thickness of the paint film, usually not less than 15um.
D, preferably washed with pure water, water conductivity control below 50um/cm.
E, control the baking time and temperature, to ensure that the paint film curing completely, the usual curing conditions are: 180 degrees C above / 30Min
