Bob,
Sometimes you want to protect IC's from the wave, connector openings,
and tooling holes as well.
Ken,
Are you using selective solder pallets? If not, that may be a
solution.
Another alternative that we use is polyimide tape. Of course this
isn't water soluble.
Also, there are silicon plugs that can be used for tooling holes.
It sounds like a tough problem. In addition to what you are looking
for, we are looking for a fast cure solder masking that is water
soluble. (Continuous flow is difficult to do if you must wait ten
minutes for the masking to cure.)
Thanks
Ryan Grant
Process Development Engineer
MCMS
(208) 898-1145
FAX (208) 898-2789
[log in to unmask]
>-----Original Message-----
>From: Lustig, Steven K.. [SMTP:[log in to unmask]]
>Sent: Wednesday, October 06, 1999 5:54 AM
>To: [log in to unmask]
>Subject: Re: [TN] Temporary Solder Mask
>
>Bob,
>
>I am neither Ken nor a Technet guru, but I'll give your question a shot
>anyway.
>
>Temporary solder mask is applied by the board assembler (not the board
>fabricator) to solderable areas (tin-lead coated areas, for example) of
>boards going through the wave that you do not to solder at this particular
>time. The solder mask is then removed after wave soldering to allow
>subsequent operations on those areas. For example, we have a connector that
>we hand solder in at a later stage (because it was easier due to other
>process issues) so we apply temporary solder mask to those PTHs. We also
>mask off SAT (select at test) resistor PTHs on that board, as well as a
>strip where we bond a part subsequently.
>
>I hope this clears things up.
>
>-Steve
>
>Steven K. Lustig
>Process Engineer
>EMS Technologies, Inc.
>Norcross, GA
>(770) 263-9200 x4714
>[log in to unmask]
>
>
>-----Original Message-----
>From: Bob Vanech [mailto:[log in to unmask]]
>Sent: Wednesday, October 06, 1999 7:22 AM
>To: [log in to unmask]
>Subject: Re: [TN] Temporary Solder Mask
>
>
> Ken or any other Technet guru..
> I am not a total novice in this business, but I
> don't understand where you would use a temp.
> soldermask. In all the application that I have been
> involved in, I worry about soldermask adhesion. Soooo,
> would someone explain so that I might become a little
> smarter before this old mind starts to head toward
> senility ??? Oh, am I already there?? Hey, thanks
> in advance. Have a great day.
> Regards,
> Bob Vanech Bob
> BVAN Enterprise
>> We have an application where we need to apply temporary solder mask prior
>> to a high temp bake in preperation for wave solder. These are polyimid
>> boards and we bake them at 125C for 12 hours prior to wave solder. We try
>> to wave solder them as soon as they cool to ambient so applying mask after
>> bake is out of the question.
>>
>> We have two different masks we currently use that are water-soluble.
>> Neither one comes off very well in the water wash and one of them leaves a
>> residue/stain due to the high temp bake.
>>
>> Do any of you have a source for a temporary solder mask that can hold up
>to
>> this temp/time and still be removed easily without residue (preferably
>with
>> water)?
>>
>>
>> Thank you,
>>
>> Ken Bloomquist
>> Sr. Principal Process Engineer
>> PRIMEX Aerospace Company
>> P.O. Box 97009
>> Redmond, WA 98073-9709
>> http://www.primextech.com
>>
>> Ph: 425-885-5000
>> FAX: 425-882-5786
>> [log in to unmask]
>>
>> Northcon/2000, Chairman of the Board
>> http://www.northcon.org
>>
>> Electronics Manufacturers Association (EMA), Vice President
>> http://www.ema-wa.org
>>
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