Phil,

Assuming that you can change the design at this stage, you have three basic choices. If you cannot change the design, go directly to the "Null Option"

1. No coat option. Mask the connector and coat the rest of the board. 
Depending on environment, the conformal coatings purpose is to keep the board clean. 
If the connector area is not subject to much dirt, not coating around and under it may be an option.

2. RTV seal. Seal the area around and under the connector with a bead of moisture cure RTV. The coating can be done before RTV with a mask operation as above. If performed after RTV seal, the conformal coating might be changed to Type SR.

3. Change the connector. Many connector series designed for use in high reliability or harsh environment systems have a version with sealed pins to prevent wicking of conformal coat.

And there is always the "null option"..... subcontract the assembly to somebody else to deal with the situation caused by the lack of a proper concurrent design process.

Steve Mikell
[log in to unmask]

> ----- Original Message -----
> From: "Crepeau, Phil (Space Technology)" <[log in to unmask]>
> To: [log in to unmask]
> Subject: [TN] conformal coat masking
> Date:         Wed, 5 Apr 2006 13:41:40 -0700
> 
> 
> hi,
> 
> we are using several qss-050-01-l-d samtec surface mount connectors on a
> printed wiring assembly that is conformal coated with a choice of either
> an ar or a pur material.  the connector pin/header interface is not
> sealed, so the conformal coating that must go under this connector has
> an easy path to wick up the leads and contaminate the mating surfaces of
> the connector.  what to do?
> 
> thanks,
> 
> phil
>




-- 
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