Jim,
Unless you are willing to spend a lot of money to test all these factors all you can say is yes to your
questions.
There is no definitive answer as to "how much" the coating has been "affected".
You have more than likely greatly exceeded the Tg of the coating. At that point all bets are off!
Trying to "certify" these boards without extensive testing would be risky at best.
David A. Douthit
manager
LoCan LLC
"Marsico, James" wrote:
> Thanks for the response, Dave, but could you elaborate? Will the
> permeability be affected? How about the Modulus? Will the TCE change?
>
> Jim Marsico
> Senior Engineer
> Production Engineering
> EDO Electronics Systems Group
> [log in to unmask] <mailto:[log in to unmask]>
> 631-595-5879
>
> -----Original Message-----
> From: David Douthit [SMTP:[log in to unmask]]
> Sent: Monday, January 28, 2002 7:49 PM
> To: [log in to unmask]
> Subject: Re: [TN] Conformal Coating
>
> Jim,
>
> You have chemically altered the polymer. It will no longer perform
> it's designed function.
>
> David A. Douthit
> Manager
> LoCan LLC
>
> "Marsico, James" wrote:
>
> > Help! Emergency!
> >
> > We have a completed assembly (top assembly with many boards,
> hybrids, etc.)
> > ready for shipment to our customer (space product). The last
> operation was
> > to ink mark a S/N. The ink is cured at 150 F for 2 hours. The
> assembly was
> > put in an oven at 150 C for two hours. After hours of reviewing
> all of the
> > materials and bill of material, component by component (component
> data,
> > supplier phone calls, etc.), the only item that is not rated for
> 150 C is
> > the polyurethane conformal coating, which turned yellow/brown in
> color. Can
> > anyone explain what actually happened to the coating and if it can
> be used
> > as is?
> >
> > Thanks,
> >
> > Jim Marsico
> > Senior Engineer
> > Production Engineering
> > EDO Electronics Systems Group
> > [log in to unmask] <mailto:[log in to unmask]>
> > 631-595-5879
> >
> >
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