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Pin-holing Problems in Nylon Coating on top of E-coating
Q. We are manufacturing steel components from OXF low carbon, high strength steel. The complete process cycle consists of: (1) stamp, (2) deburr, (3)e-coat &(4) apply a partial fluidize bed coat on one end of the part. The nylon coating exhibits massive "pin-holing". It appears to me that "gassing out" is occurring during the pre-heat stage of the nylon application and continues to do so while the nylon is curing from the heat of the metal.
I have discussed this situation with both the e-coater and the nylon coater to see if we can resolve the problem. However, the e-coater claims that he meets all the specification call-outs for the e-coat film and the problem is not from their source and, the nylon coater claims the same. Can anyone enlighten us to what may be occurring here? Does it appear to be an e-coating problem or a nylon coating problem?
P.S. We have taken complete lots of e-coated parts which could not be nylon coated without pin-holing and stress relieved them @ 375 °F for a couple of hours and then nylon coated with no problems.
Note: E-coating and nylon coating done by others. (P.Q.)
- Midland, Ontario, Canada.
2002
A. Dear Mr. Quesnelle,
It sounds to me that he E coat is not completely cured. Check with your supplier the conveyor speed and temp. settings of the oven. Make a time-temp graph (the E-coat supplier should have the equipment); and do not only measure the air-temp in the oven but also the temp of the coated piece.
Good luck,
Remmelt Bosklopper
- Enschede, The Netherlands
2002
Q. Dear sir
Could you please explain to me process of nylon coating. Why & where it is used?
Thanks,
marketing - India
June 3, 2008
A. Hi, Bhupinder. Nylon is a thermoplastic that can be applied to objects as a powder coating. The parts are preheated, put into a fluidized bed tank containing the nylon powder, then baked to fuse the powder into a continuous coating. Nylon coatings would be thicker and more expensive than thermoset powder coatings like polyester or epoxy.
But it takes a thousand "ifs, ands, & buts" to answer abstract questions about overall technologies, so books are written for the case where questions are very general, and there is no way to condense them to internet forum length. However, if you can tell us your own individual situation, including the particular parts you have in mind and the application, I think we can probably help you decide whether nylon powder coating is a good choice for them. Thanks!
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
June 3, 2008
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