Analysis of Peeled-off problem for Electro-plating and Powder coating parts

2021-09-14

Analysis of Peeled-off problem for Electro-plating and Powder coating parts

 
1. Causes lead to plating layers peeled off and preventive measures for Electro-plating parts:
 

 
1) The key to achieving good adhesion is to ensure an active metal surface sufficiently void of oils, oxides, alloying inclusions or heat treat scale. If pretreatment is not well done, the contaminations remained on metal surface will weak the adhesion.
 
Preventive measures: check every batch to make sure the removal of oil is thorough, the cleaning water is clean, the concentration of acid leaching solution is heavy as required and the etching time is enough.
 
2) It may be that the interruption of the current in the electroplating process causes the poor combination between the nickel layer and product, and this current interruption phenomenon may be caused by the poor conductivity of the hanging device. 
 
Preventive measures: daily check the hanging devices to make sure there is no damage.
 
3) When the brightener is added too much, the bonding force between plating layers is not good.
 
Preventive measures: daily check the electro-plating solution including brightener to be made according to standards.
 
4) PH value, electric current, temperature could also be the causes. 
 
Preventive measures: daily check the electro-plating solution and plating equipment.
 
2. Causes lead to incomplete and peeled-off coating and preventive measures for Powder coated parts:
     
 
1) Incomplete coating:
 
If the coating line is automatic, it could be the causes that the rotating speed of hanging devices and distance between parts and blowguns are too far or too close. The small positions inside the cavity cannot be completely covered with coating powder.
 
If the coating line is manual, workers didn't perform a qualified work.
 
Preventive measures: For automatic coating line, set up the proper rotating speed of hanging distance between parts and blowguns. For manual line, train the workers to work more careful and check every piece.
 
2) Peeled-off coating:
 
Mains causes could be Pretreatment insufficient, Drying time too short or temperature too low.
 
Preventive measures: Pretreatment to remove the contaminations must be thorough, such as oil, lubricant, oxides, alloying inclusions or heat treat scale.
Prolong the drying time or set up a higher drying temperature according to work instruction.