Edward,
In my opinion, it only works reliably using a
dry film soldermask laminator to apply the
striping resist.
We currently use a (very 'classic') DuPont product,
4200 series, thickness 3mils. It is not in
production anymore, so we must change soon.
I don't think type of resist is critical, but
vacuum sure is.
regards
Torben Østeraa
Printca AS
>>-----Original Message-----
>>From: edward Edward Szpruch [mailto:[log in to unmask]]
>>Sent: Wednesday, September 15, 1999 10:34 AM
>>To: [log in to unmask]
>>Subject: Re: [TN] Surface finishing -Reply
>>
>>
>>Hi Jac,
>>I am just wondering how your selective stripping is
>>working?Probably you are
>>using selective masking ( photoresist) to protect the areas
>>destignated for
>>reflow.What kind of photoresist are you using and what about
>>overlaping
>>between tin-lead stripped pattern and solder mask pattern?
>>In the past we made trials and we faced the following problems:
>>1) leaking of tin-lead stripping solution along lines.This
>>resulted non
>>clear boundary between the sections that were destignated for
>>reflow and
>>those destignated to be covered by solder mask.
>>2) as result of the previous,we got exposed copper ar the
>>boundary of the
>>"reflow side" and tin-lead on the "solder mask" side.
>>Regards
>>
>>Edward Szpruch
>>Eltek , Manager of Process Engineering
>>P.O.Box 159 ; 49101 Petah Tikva Israel
>>Tel ++972 3 9395050 , Fax ++972 3 9309581
>>e-mail [log in to unmask]
>>
>>> -----Original Message-----
>>> From: Jac Kroeker [SMTP:[log in to unmask]]
>>> Sent: ? ?????? 14 1999 22:08
>>> To: [log in to unmask]
>>> Subject: Re: [TN] Surface finishing -Reply
>>>
>>> Hi Ron and Phil;
>>> We do a selective tin lead strip. This allows us to put
>>solder mask on
>>> bare
>>> copper, eliminating the problem of the wrinkling mask. Plating the
>>> tin/lead
>>> also increases the control of the amount of tin/lead
>>remaining on the
>>> pads.
>>> Result - almost flat smd pads.
>>> Jac Kroeker
>>>
>>> At 08:57 AM 09/14/1999 -0700, you wrote:
>>> >Hi Phil,
>>> >I remember the days at Burroughs with the tin lead plate and
>>> >IR fuse. The only draw back to tin lead plate and fuse, is
>>> >that you are putting solder mask over the fused solder,
>>> >which has a tendancy to wrinkle and possibly flake off during
>>> >or after any subsequent soldering operation.
>>> >Ron Hayashi
>>> >
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