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How to Increase DFT Paint Thickness in Cathodic Electrodeposition (CED) system?
← Ed. note: Readers, please describe the details of your own situation Huh? Why?
Q. What will be the DFT variation in aluminium as compared to sheet metal component when DFT related bath parameters are constant?
Mustafa khanQ. Head - Faridabad, Haryana
February 14, 2023
Q. I am Working In CED Paint shop. We are applying 250V at step 1 and 300V at step 2. But still coating thickness is <10µm (STD 18 ~ 22 µm)
*E-Coat Bath Parameters*
pH - 4.8
Conductivity - 1172µS/cm
NVM - 19.82%
Ash - 21.7%
anolyte conductivity - 1200 µS/cm.
Part - Galvanized
MEQ - 32.44
Bath Size = 68 cu. m.
permeate Flow = 20 L/min
*Coating Parameters*
Coating/Bath Temperature = 32 °C
Coating Time = 4 min
Soft Strat/Ramp-up Time = 30 sec
Step 1 Voltage = 280 V
Step 2 Voltage = 300 V
Area to be Coated - 118 sq.m
inside Area DFT < 6 µm
Outside area DFT < 10µm
Please help me How to increase DFT on E-Coat/CED components?
- Lahore, Pakistan
February 18, 2023
A. Hi Arslan.
I do not have any experience in this to be able to help you, but I note that dozens of readers have the opposite problem -- thickness greater than they want -- and Topic 23047 "How to reduce CED paint thickness?" will tell you what they had to do to decrease thickness. This may well tell you what you are doing which is limiting your thickness :-)
Luck & Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
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Q. Thickness problem: Is there any relation between thickness of CED coating & and anolyte conductivity?
Avinash VidhateDirector - Nashik, Maharashtra, India
2007
A. There is no relationship between CED film thickness and anolyte conductivity as long as your CED bath conductivity and anolyte conductivity is within the spec.
Anions (CH3COO-) are generated during CED process and it is moving to Anolyte system through semi permeable membrane at the anodes thereby the conductivity of anolyte increases and replenished with DI (maintained with in the spec between 400 - 400 microsiemens). If anolyte system is not removing the Anions then it will be remain in CED bath then the conductivity of bath slowly increases making a difference in film formation.
Please check paint supplier for Bath conductivity and Anolyte conductivity spec.
P.M.Saravanan
paint shop manager
Chennai, Tamilnadu, India
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Q. I am Working In CED Paint shop. We are applying 230 V and
pH - 5.82
Conductivity - 1452
NVM - 16.82
But DFT is coming in 5- 10 Micron. Please Tell me How to increase DFT on CED components?
CED Paint Shop - Faridabad Haryana
January 31, 2019
Q. Dear sir;
I am working CED line for past 8 years. I faced a lot of problems and I found solutions for them all, but now we are facing a new problem for past 2 years, and it's increasing gradually:
Low DFT --
Components are coated with less DFT (lower side) remaining sides are uncoated with zero dft (upper side) of same components.
Please someone give a solution for this problem.
Thanks all.
- CHENNAI TAMILNADU
March 27, 2021