xn58xn58 said:
Dear all,
I first time work with e-coating process. I hope anyone to provide me a process inspection plan, such as when to inspect, what stage to inspect, how frequent to inspect, what need to be inspected.etc.
Also, if you know the common drfects and root reasons, please also advise.
thank you very much.
If you have any contacts in automotive, they may be able to help. In a former life, I worked for a Tier 1 supplier to automotive. We first purchased, then e-coated internally weldments to automotive. Mazda had an excellent specification for e-coat testing.
I don't have access to a control plan anymore, but I can provide some from memory. First, your cleaning operations are critical. Temperature, dwell time, concentration of cleaner, cleanliness (conductivity) of rinse are a few.
In the coating process, total surface area to be coated, voltage (based on surface area), concentration, temperature, dwell time.
Bake process is basically time and temperature.
Some quality tests are salt spray corrosion, scratch test (test in heat zone areas if welded; use tape to test adhesion), visual (orange peel, color), thickness.
Coat rack design is critical. You need good conductivity to coat the correct thickness. If your parts are heavy, they can hang on the edge of a triangular cross-section hook. If they are light, there is atendency to float off when submerged, so you will need a springlike retainer. The hook/retainer will leave a mark, so these need to be located in a non-critical/visible area.