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Fri, 4 Dec 1998 16:35:05 -0400 |
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J.J. MacKay Canada Limited |
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We use the Dow 1-2577 also, and have had success in reducing the cure
time by heating with humidity (as this is a moisture cure product).
As the cure time is greatly thickness dependent you should try the
process on a small number of boards first. If "bubbling" is present
then you may need to increase the air dry time.
The general process goes something like this:
- Dip - air dry approximately x hrs (depends on thickness)
- Oven cure @60C 50%RH for 1 hrs (or more, thickness dependent) Do not
use the 80C as suggested in the Dow Q1-2577 Specs.
- Stand 4 hours.
I would suggest talking to Kelly Wall at Dow Cornings Customer Support
tel: (517)496-6546, he was most helpful in our situation.
Good luck,
Brent
Benjamin G. Thomas wrote:
>
> We currently run a PCB coating system using Dow 1/2577 conformal
> coating.
> Our complete curing cycle runs 24hrs.
> I am looking for ways to decrease the curing time.
>
> I would greatly appreciate any suggestions.
>
> Here's some more information for reference:
> We use two application techniques:
> 1.) Hand Dipping (complete submersion)
> 2.) Dispensing with a PVA1000
> Total coating thickness required is approx. 50mils, PER our
> environmental requirements.
> Hand dipping requires 3 separate coats to achieve this thickness.
> PVA1000 dispensing only requires one coat, but each side still needs to
> be cured for 24hrs.
> PCBs are handled manually, and cured on drying racks in a hooded area
> with forced ventilation.
> Hand-dipped boards then go through a lengthy "unmasking" procedure to
> trim and remove excess coating.
>
> -Benjamin G. Thomas
>
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