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CED paint entrapment, capillary action problem
Q. We manufacture automotive car wheels. After CED painting there is a paint entrapment which remains due to surface tension in the interference of the rim & disc. This entrapped paint gets baked and looks awkward & gets highlighted after top coat. Could you please suggest some solution to overcome this problem?
Mohankrishna G- Bhuj, Gujarat, India
June 15, 2009
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A. I think it is the problem of cleaning . Your internal disc areas area not getting cleaned properly. Try to check your spray nozzle conditions and spray pressure.
Manish Dhyani- New Delhi, India
A. Do you have a line where the pretreatment is a spray process only?
If yes (only if yes), then the crevice between the two shells welded together is probably not getting cleaned.
Unfortunately, E-coat is a dip process and when E-coat comes in contact with area that has not been cleaned and phosphated properly you will end up with undesired results.
Mohali, Punjab, India
A. This is related to capillary action more than the cleaning before CED. Set the nozzle spray to hit crevice areas and after post rinses apply air blow in flash off zone. Due to capillary action CED paint makes a path between Rim and disc which looks like some blockage.
Amit Singh- Jamshedpur, India
December 30, 2010
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