Like other construction methods, electrodeposition painting may also have one or another defect in the paint film due to improper construction operation control. The following table collects some paint film morbidity, causes and solutions that often occur in electrodeposition painting.
| paint film sick | cause | solution |
| Redissolve pinholes | 1. The amount of amine in the paint solution is too large, and the pH value is too high 2. The amount of co-solvent is too large 3. The time spent between painting and washing is too long, and the speed of the conveyor belt is too slow | 1. Add low-amine paint, remove excess amine with cathode cover, and adjust pH value of paint solution 2. Add paint with less amount of co-solvent 3. Shorten the time from painting to washing and speed up the conveying speed |
| Bubble pinhole | 1. There are too many impurity ions in the paint liquid, and the conductivity is large 2. The voltage is too high, the electrolytic reaction is intense, and there are too many bubbles 3. The amount of co-solvent is too low 4. The temperature of the paint liquid is too low, and the air bubbles are not easy to discharge | 1. The cathode diaphragm removes impurity ions 2. Appropriately reduce the electric ball 3. Appropriately add co-solvent 4. Strictly control the temperature of the paint liquid |
| stepped pinhole | 1. The ratio of resin to pigment is too large 2. If there is too little co-solvent, the bubbles in the paint liquid are difficult to disappear 3. The non-volatile content of the paint solution is too low 3. The surface of the object to be coated does not wet well with the paint solution, and the bubbles stagnate on the surface after the object to be coated is immersed in the paint solution 4. The voltage is too high 5. The speed of the conveyor belt is too slow | 1. Add paint with large pigment-to-base ratio 2. Appropriately add co-solvent 3. Increase the non-volatile content of the paint solution 4. Improve the surface pretreatment of the coated object 5. Reduce the voltage 6. Accelerate the conveying speed |
| large pinhole | 1. The pigment-base ratio of the paint liquid is large 2. Oil is mixed in the paint liquid 3. Incomplete pre-treatment degreasing 4. The phosphating film is too thin 5. The voltage is too high 6. The paint temperature is too high | 1. Add paint with low pigment-base ratio 2. Strict management to prevent oil from entering the tank 3. Strictly control the pre-treatment 4. Control the quality of phosphating film 5. Properly reduce the voltage 6. Reduce paint temperature |
| orange peel | 1. The ratio of the paint solution to the base ratio is too small 2. Impurity ions are mixed into the paint solution 3. Less co-solvent 4. The low molecular base resin in the paint solution increases 5. Rough phosphating film 6. Incomplete washing after pretreatment 7. The voltage is too high | 1. Add paint with high pigment-base ratio 2. The cathode diaphragm removes impurity ions 3. Appropriately add the amount of co-solvent 4. Strictly control the quality of electrophoretic paint 5. Improve surface treatment quality 6. Washing after pretreatment should be as complete as possible 7. Properly reduce the voltage |
| Water marks | 1. The pigment-to-base ratio of the paint liquid is too small 2. The amount of co-solvent is too large 3. The increase of low molecular weight resin in the paint solution 4. Inappropriate neutralizing dose 5. There are too many impurity ions in the paint solution 6. The pre-treatment phosphating film is too thin 7. Incomplete washing after pretreatment 8. The pre-drying time before entering the oven after painting is too short 9. The surface tension of the coating resin is too large | 1. Add paint with high pigment-base ratio 2. Add paint with small amount of co-solvent 3. Strictly control the quality of electrophoretic paint 4. Adjust the pH value 5. The anode diaphragm removes impurity ions 6. Strictly control the quality of phosphating film 7. Strictly control the quality of washing after pretreatment 8. Add pre-drying equipment (preheating) before entering the oven 9. Improve the surface tension of the paint film |
| Peeling paint film | 1. Excessive leaching during phosphating film electrodeposition 2. The phosphating film is too thick 3. There are too many impurity ions in the paint solution 4. Yan-base ratio is too small 5. The amount of low molecular resin in the paint liquid increases 6. The voltage is too high 7. Excessive washing pressure after electrodeposition painting | 1. Strictly control the quality of phosphating film 2. The cathode diaphragm removes impurity ions 3. Adjust the color-to-base ratio 4. Strictly control the quality of the added paint 5. Properly reduce the voltage 6. Reduce the washing water pressure |
| Rough paint film | 1. The amount of amine in the paint solution is too small 2. Coagulation of resin in the paint solution 3. There are too many impurity ions in the paint solution 4. There are many mechanical impurities mixed into the paint liquid 5. Pigment dispersion is not good 6. Uneven mixing 7. The temperature of the paint liquid or the object to be coated is too high | 1. Adjust the pH value of the paint solution 2. Improve the quality of paint 3. The cathode diaphragm removes impurity ions 4. Filter the electrodeposition paint solution to remove mechanical impurities 5. Before electrodeposition painting, it should be fully stirred; or the surface of the pigment should be pretreated 6. Fully stir before electrodeposition 7. Strictly control the construction temperature |
Yin and Yang sides (the gloss of the paint film on the same object is inconsistent ) | 1. The pigment-base ratio of the paint liquid is not appropriate, or the pigment dispersion is not good 2. The position of the object to be coated is inappropriate 3. The paint liquid is not stirred evenly 4. The geometric shape of the object to be coated is too complex, forming a power line shielding phenomenon | 1. Adjust the pigment-base ratio and stirring speed of the paint liquid 2. The position of the object to be coated should be as parallel as possible to the cathode 3. Adjust the stirring speed, it should not be too fast 4. According to the specific shape of the workpiece, the auxiliary cathode can be installed |
