Hello guy,
I have no knowledge about the spot mask. Could you elaborate this method?
Best Regards,
Eric
On Tue, 19 Feb 2002 13:28:10 -0500, Guy Ramsey <[log in to unmask]> wrote:
>Have you considered temporary spot mask? It works okay for chip resistors
>and capacitors, SOT. Not too good for SOIC, stuff gets stuck under the
>little legs.
>
>> -----Original Message-----
>> From: TechNet [mailto:[log in to unmask]]On Behalf Of makshuwing
>> Sent: Tuesday, February 19, 2002 6:18 AM
>> To: [log in to unmask]
>> Subject: Re: [TN] High temperature solder wire
>>
>>
>> Hello Peter,
>>
>> Adhesive dispensing, chip placement, reflow(glue curing), manual
>> insertion, then wave soldering are our normal processes. After
>> reflow we sometimes find some mis-aligned chips or missing
>> components. The area of glue in contact with the surface of the
>> mis-aligned chip could be less than normal and the adhesion force
>> is insufficient to protect the chip from dropping off during
>> wave soldering. Therefore we want to use high temp solder to
>> solder the mis-aligned chips prior to wave soldering. We know
>> that we could detach the parts after reflow and hand solder the
>> parts after the wave soldering but we think adding hi-temp solder
>> is the simpliest way since there is no detachment process is involved.
>>
>> Eric
>> ----- Original Message -----
>> From: "Peter Barton" <[log in to unmask]>
>> To: <[log in to unmask]>
>> Sent: Tuesday, February 19, 2002 12:41 AM
>> Subject: Re: [TN] High temperature solder wire
>>
>>
>> > If you are going to the trouble to hand solder these parts on
>> why not fit
>> > them after the wave solder process and just tack them on,
>> applying a dab of
>> > rework flux first, then reflowing the solder that will be present on
the
>> > pads? Saves the difficulty of using high temp solder pre-wave, and
quite
>> > likely excessive solder on the joints post wave (the solder in your
bath
>> > will wet to the high temp. joints already made). I have seen a similar
>> > problem when tack soldering large multi way connectors with high temp.
>> > solder pre-wave.
>> >
>> > Regards,
>> >
>> > Peter Barton
>> >
>> > ===== Original Message from [log in to unmask] (TechNet E-Mail Forum.) at
>> > 18/02/02 13:40
>> > >Hi all,
>> > >
>> > >We are currently using adhesive to glue chips on PCB and then
>> run the board on reflow oven
>> > followed by wave soldering. After the reflow process we need to
>> rework some
>> > chips occasionally due to chip miss-alignment or missing. To do
>> the rework
>> > we have to remove the original glue, re-glue the chips and let
>> the board go
>> > through the reflow process again. Now we want to eliminate this loop by
>> > using hi-temp solder wire (melting point 268-302 degree C) to solder
the
>> > reworked chips without adhesive, then let the reworked board
>> directly go to
>> > wave soldering with solder pot temperature around 245 degree C.
>> > >
>> > >Has anyone using this method seen problems?
>> > >
>> > >Eric
>> >
>> >
>> > -----------------------------------------------------------------------
>> > Peter Barton
>> >
>> > ACW Technology Ltd
>> > Dinas Isaf West
>> > Tonypandy
>> > Mid Glamorgan. CF40 1XX Wales
>> >
>> > Tel: 01443 425200 Fax: 01443 436882
>> >
>> > International Tel : +44 1443 425200 Fax : +44 1443 436882
>> >
>> > E-mail: [log in to unmask] Website/URL: www.acw.co.uk
>> >
>> >
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>> >
>>
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Hello guy,
I have no knowledge about the spot mask. Could you elaborate this method?
Best Regards,
Eric
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