Cleaning Process For Polyurthene Conformal Coating

There is none. Any solvent that attack PU will attack most other plastics.

Toluene will make it swell, but you still have to scrape it off. I've used selective mechanical removal, under a microscope, but I was dealing with very expensive boards.

Give us some real details, not just "what removes PU".

which type details do u want sir?

Are you removing all the coating? Why?

Can you selectively remove coating?

Have you asked the coating supplier for help? What is the coating name/number/supplier?

Did you apply the coating? How long has the coating been on the boards? How was it cured?

What have you tried so far?

What facilities do you have for rework?

That's enough for now.

i want remove at problem component&around that place for replacing the component.

yes.

humiseal is our supplier,they suggested one gel that is stripper 1063 gel.we r using p.u conformal coating.

yes,life time,it is cured at ambient temperature,

stripper 1063 gel,

presently fecilities r not there.we r searching..

There are more aggressive strippers, but they eat everything else, too.

I have no suggestions for you, unless you want to fly me to your facility to evaluate the process and make recommendations.

thanks for valuable feed back

Maybe these boards are better suited to total replacement rather than component-wise repair.

there is no Royal Road. This is a mechanically intensive task. Are these through hole or surface mount?

There is a hot air surface mount removal tool that I have used. It has shaped air nozzles for each type part, but you need to debride the coating for heat to penetrate and even then the coating might be in the underneath space and cements the flat bottom of the part down and heat takes time. The good thing, heat does soften urethane? Test on scrap boards, or use a service who have done this 100,000 times and have the tools, and know-how. these will help

conformal coating removal

ways and means

we are using through hole and surface mount components.thanks for u r feed back.

I have successfully used a French product sold as "DECAPEX" a paint remover based on dichloromethane for softening and removal even thermoset resins.

Unfortunately, printed circuit boards are manufactured with thermoset resins. They will be dissolved, too. The trick is removing the solvent at the right moment so you don't eat into the board. It isn't easy to do. Been there, done that.

Might help.

Years ago, in industry, I taught classes in the application of conformal coatings for a huge electronics company. All our stuff was high end military and aerospace hardware. We coated thousands of boards/week, all by manual spray and dip.

We didn't teach them how to remove cured coatings, as it was much too difficult to do without scrapping the board. That was only handled by specially trained technicians.

Sounds like the OP might want to send them out to a contract manufacturer who is skilled in removal.

Reading your NEPCON piece brought back memories. (Good find)

One thing in the article bears repeating. Burning PU coatings produces toxic fumes.

presently we apply the conformal coating with machine only.

We had to remove glass covers from diode arrays,

the manufacturer had changed the glue to a much better type - no one of the existing procedures would work.

If tried too aggressively the plastic IC-housing was dissolved.

Finally we burnt the glue with a finely tunable Nd-YAG laser.

Depending on the absorption characteristics of your conformal coating this may be suitable too, if you can burn off the coating and let intact the PCB.

RHABE

Not sure but have you tried dry ice blasting?