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August 1997

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Subject:
From:
annie laberge <[log in to unmask]>
Reply To:
TechNet Mail Forum.
Date:
Thu, 14 Aug 1997 16:49:39 -0400
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Regarding SMOBC, liquid photo, what would (in general) be the maximum
temperature and time a solder mask can hold before any deterioration occur
in a reflow oven?

Same question but for PCB built with  standard FR4 material, 6-8
layers...what is the MAXIMUM  temperature and time suggested in a reflow
oven for this type of PCB ?

Thank you in advance

ALaberge


At 02:03 PM 8/14/97 -0500, you wrote:
>John,
>
>Rather than looking for a different solder mask material you might want to
>change the board design to SMOBC (solder mask over bare copper).  If
>you change to SMOBC, the tin could not reflow & therefore cause the
>solder mask to bubble & lift.
>
>>>> JOHN OSULLIVAN
><[log in to unmask]> 08/14/97
04:49pm >>>
>  REGARDING           Solder mask material
>
>With regard to different solder mask material I'm interested in finding out if
>some solder mask materials have differnet thermal masking abilities.
>The reason I ask is because of a board I am wave soldering which has
>heavy
>copper layers internally, which forces me to pass the board through the
>preheat stage (and over wave) very slowly. The board was
>manufactured using
>all over tin/lead reflow. The tin/lead under the solder mask on large tracks
>are reflowing grosely and causing the soldermask to bubble/blister and
>crack
>off, failing the infamous 'tape test'.
>
>Any comments.
>
>Dennis Ostendorf
>aaeee2o @snds.com
>
>


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