Where is the problem of pinholes in the paint film of electrophoresis technology?
Due to problems in the management of the production line, or deviations in measurement data or inaccurate parameters, it will affect the paint film of the coating workpiece, resulting in various defects in the electrophoretic paint film. However, the most common paint film defects are pinholes, watermarks, particles, shrinkage, abnormal adhesion, uneven color, and so on.
What is the pinhole of the paint film? Paint pinhole refers to the phenomenon of pinholes like pinpoints in the paint film on the surface of the workpiece after electrophoresis. There are three reasons for pinholes.
First, the reason for charging into the tank
1. There are air bubbles on the surface of the electrophoresis tank into the tank section, and the small surface velocity of the tank fluid circulation is low.
2. The surface of the workpiece is not wet enough to be electrophoretic painted.
3. For the climbing track coating production line, the chain speed may be too low, the voltage in the slot section is too high, and the electrolytic reaction is too strong;
4. The reason for the low ash content in the bath and the low content of cosolvent.
Second, the reason for paint film redissolution
1. The pH value of the bath is too low, which causes the paint film to dissolve.
2. The content of co-solvent in the bath is on the high side.
3. The washing after the electrophoresis process is not timely, or the waiting time for washing is too long.
4. The coated workpiece stays too long in the electrophoresis tank.
Third, bubbles cause
1. The electrophoretic voltage parameter is too high, too much electrolytic reaction leads to too many bubbles.
2. The temperature of the bath is too low, and the defoaming is not clean due to insufficient stirring of the bath.
3. The conductivity of the electrophoresis bath is high, and there are many impurities.
4. Low co-solvent content and excessive viscosity of the bath.
In addition to the above reasons, the pinhole phenomenon of the electrophoretic paint film can be caused by many other reasons. For example, the surface of the electrophoretic workpiece is caused by uneven conductivity or insufficient pre-treatment, which will cause pinhole phenomena under low voltage. Or the quality of the electrophoresis power supply is not stable and the output current waveform is unstable resulting in pinholes. Pinholes may also be caused by abnormal coating films caused by trace amounts of grease. Therefore, when you see the pinhole problem of the product, you must objectively and symptomatically analyze the problem to find an effective solution.
For more solutions to the disadvantages of electrophoretic paint films, please pay attention to our official website of electrophoretic paint luyzsw.com, or contact us by phone: 0755-89264486.