Thanks Doug and Phil,
The connectors do not need environmental sealing, I just need to figure out how to stop coating wicking on the pins.
Now sealing around the connectors just to liquid coating infiltration proof them will definitely apply a thicker layer on the joints and I wonder if this could be detrimental to the long term reliability. Am I right?
Regards,
Ioan Tempea, ing.
Ingénieur principal de fabrication / Senior Manufacturing Engineer
[signature002]<http://www.digico.cc/>
950 RUE BERGAR, LAVAL, QC, H7L 5A1<http://g.co/maps/2gh3f>
T+ 1 (450) 967-7100, EXT244
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Lauréat Dunamis 2012<http://digico.cc/dunamis-2012/>
Entreprise manufacturière / Gestion du capital humain
De : [log in to unmask] [mailto:[log in to unmask]]
Envoyé : January-21-13 10:00 AM
À : TechNet E-Mail Forum; Ioan Tempea
Objet : Re: [TN] Coating around connectors
Ioan,
I guess it depends on what your end use environment is. If it is a condensing humidity environment, or the possibility that condensed water will flow into the connector, then you would want the connectors permanently sealed off. Phil Kinner has given some good suggestions on dispensing quick cure masking materials, but then you need to remove those materials and that leaves some openings in the coating.
What I might suggest is using a benchtop dispensor, such as a PVA350, and dispense a UV cure adhesive/sealant around your connectors. You can quickly cure it, then coat up to that material or on it if you prefer, and you seal off the connector.
Doug Pauls
From: Ioan Tempea <[log in to unmask]<mailto:[log in to unmask]>>
To: <[log in to unmask]<mailto:[log in to unmask]>>
Date: 01/21/2013 07:07 AM
Subject: [TN] Coating around connectors
Sent by: TechNet <[log in to unmask]<mailto:[log in to unmask]>>
________________________________
Dear Technos,
Got a tough one now!
We apply 1B31S with our Asymtek selective coating machine and there are 8 difficult connectors, where coating infiltrates inside and on the pins. What can I do to prevent this from happening?
We've tried to manually lay down some non-diluted coating around the parts. Kinda stops infiltration, but it's long and manual, many bubbles in the coating layer. We've tried gel coating around the connectors, but it cracks, leaving a lot of room for infiltration. Not to mention that the closer the selective nozzle gets to connectors, the more prone we are to finding spots on the pins (it seems impossible to completely eliminate satellites when the nozzle head changes direction or at start-stop).
Ideally we would find something that can be dispensed around those connectors in a controlled manner (even if we need to buy some sort of table top dispensing machine) so that we seal them, followed by selective dispensing on the rest of the board. We really want zero or minimal manual work, as it's not repeatable.
Any suggestions?
Thanks,
Ioan Tempea, ing.
Ingénieur principal de fabrication / Senior Manufacturing Engineer
[signature002]<http://www.digico.cc/>
950 RUE BERGAR, LAVAL, QC, H7L 5A1<http://g.co/maps/2gh3f>
T+ 1 (450) 967-7100, EXT244
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[signature001] <http://www.facebook.com/pages/Digico/277076778479>
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Lauréat Dunamis 2012<http://digico.cc/dunamis-2012/>
Entreprise manufacturière / Gestion du capital humain
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