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August 1997

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Subject:
From:
Afri Singh <[log in to unmask]>
Reply To:
TechNet Mail Forum.
Date:
Fri, 15 Aug 1997 15:27:58 -0400
Content-Type:
TEXT/PLAIN
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TEXT/PLAIN (54 lines)
Hello Annie. We rep the ASI/coates mask and have gone up to 13 seconds on a
moving solder without any cracks/deterioration. This was with one coat. A
thick coat will protect it futher. You could have your supplier provide you
with a scrap board and run the same test on your oven    Afri

On Thu, 14 Aug 1997, annie laberge wrote:

> 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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