(1) Remelting pinholes appear in the paint film
Cause Analysis:
1) The amount of amine in the paint solution is too large, the pH value is too high,
2) Too much co-solvent,
3) The time from painting to washing is too long, and the speed of the conveyor belt is too slow.
Solution:
1) adjust the pH value,
2) Add paint with less co-solvent,
3) Shorten the residence time and speed up the transmission speed
(2) Bubble pinholes appear
Cause Analysis:
1) There are too many impurities in the paint liquid, and the conductivity is large.
2) High voltage, intense electrolytic reaction, too many bubbles,
3) The amount of solvent is too small,
4) The temperature of the paint liquid is too low, the air bubbles are not easy to discharge,
Approach:
1) Use cathode hood or ultrafiltration device to remove impurity ions,
2) By lowering the voltage,
3) Add an appropriate amount of co-solvent,
4) Control the temperature of the paint liquid to the specified range,
(3) Large pinholes appear
Cause Analysis:
1) The pigment-to-base ratio of the paint liquid is large,
2) Oil is mixed into the paint liquid or the pretreatment degreasing does not make the primer,
3) Coarse phosphate coating,
4) The voltage is too high,
5) The paint temperature is too high,
Approach:
1) Add paint with low frequency-to-base ratio,
2) Strengthen management, strict pretreatment before coating,
3) shorten the phosphating time, improve the residual quality,
4) Properly reduce the voltage,
5) Reduce the temperature of the paint solution,
(4) Orange peel appears
Original analysis:
1) The pigment-base ratio of the paint liquid is too small,
2) Impurity ions are mixed into the paint solution,
3) The low molecular weight resin in the paint solution increases,
4) The amount of mobile solvent is small,
5) The phosphating film is rough,
6) Incomplete washing after pretreatment,
7) The voltage is too high and the paint film is too thick.
Approach:
1) add new paint,
2) Use a cathode hood or an ultrafiltration device to remove impurities,
3) Strengthen paint inspection,
4) Appropriately increase the co-solvent,
5) Adjust the phosphating solution to ensure the quality of the phosphating film is qualified,
6) Extend the washing time,
7) Reduce the voltage appropriately,
(5) Peeling of paint film
Cause Analysis:
1) The leaching amount is too much during the electrodeposition of the phosphating film,
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 low molecular weight resin in the paint liquid increases,
6) The voltage is too low or too high,
7) The water washing pressure is too large after the current product,
Approach:
1) Strictly control the quality of phosphating film,
2) The cathode diaphragm removes impurity ions,
3) Adjust the color-base ratio,
4) Strictly control the quality of joining and sending,
5) Adjust the voltage,
6) Reduce the pressure of the flushing water,
There are other defects such as rough paint film, water marks, inconsistent gloss, poor adhesion, etc., and the treatment methods are basically the same.
