Tenison,
I am not experiencing the problem you are describing. We are also using a
Smartsonic Model 5000 cleaner with the 440-R detergent, and so far, I have
not seen any degradation to the stencils. The only issue I've seen is the
part number nameplates, which are glued on the frame, tend to fall off.
We are typically going about 3 weeks before changing the cleaning
solution, and we clean about 5-10 stencils per day, plus some misprint
boards. When we clean wave solder fixtures, we typically wait until just
before the cleaning solution is drained, to limit the flux nasties from
contaminating the solution. So far, the stencils are clean and no damage
has been observed. By the way, we are using tap water, due to cost
constraints.
Howard Watson
[log in to unmask]
Sent by: TechNet <[log in to unmask]>
02/20/01 09:24 AM
Please respond to "TechNet E-Mail Forum."; Please respond to Tenison_Stone
To: [log in to unmask]
cc:
Subject: Re: [TN] Stencils with glue releasing
Ahne,
1. We run the stencil cleaner at room temperature - maybe colder when
water is changed
2. we use smartsonic 440-R smt detergent made for the cleaner
3. We use a standard smartsonic ultrasonic stencil cleaner
4. Production told me they change the detergent when the boards are not
clean after the cleaning cycle is done.
I am not comfortable with this method. What does everyone recommend
for changing the cleaning solution?
Tenison Stone
"Ahne Oosterhof" <[log in to unmask]> on 02/20/2001 10:06:48 AM
Please respond to <[log in to unmask]>
To: "'TechNet E-Mail Forum.'" <[log in to unmask]>,
<[log in to unmask]>
cc:
Subject: RE: [TN] Stencils with glue releasing
Good morning Tenison,
We are in the business of making stencils and have learned a few things
about glue and how well it holds up.
The major reasons why glue may let go:
1) The cleaning temperature is too high. Most glues and epoxies used to
attach stencil plates to the mesh and mesh to the frame is chosen to
release
at temperatures over 140F. I suggest you try to keep your cleaner
temperature below 120F.
2) Using a cleaning solution that attacks glues and epoxies. Several
brands
of these materials will dissolve glues, especially when used at high
concentrations. Never use these materials at concentrations higher than
recommended by the manufacturer and try to stay well below them if
possible.
3) Ultrasonic cleaning ( and sometimes high pressure cleaning) may have an
impact on glue attachment and may cause a slow, progressive release of
some
glues.
4) Over time and use the solution in your tanks may change drastically due
to the addition of the residues you are removing from the stencils. Keep
track of the contents of the tanks.
Please give me a call to discuss your specific problem and how you can
resolve it.
Regards,
Ahne Oosterhof
A-Laser, Inc.
(503)641-9428
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of
[log in to unmask]
Sent: Tuesday, February 20, 2001 05:35
To: [log in to unmask]
Subject: [TN] Stencils with glue releasing
Hi everyone!
My problem today has to do with stencils for solder paste printing.
We are having a lot of problems with the glue releasing when we go to use
the stencil. Packing tape will hold through the end of the job. The
temperature is OK and the time in cleaner is acceptable according to the
stencil vendor.
We have checkout our stencil cleaner and the parameters on the various
printers.
We have had our stencil cleaner for many years and only had the problem in
the last year.'
We have had no luck with the problem and the stencil vendor is also
confused.
Has anyone had this problem before and found a solution?
Tenison Stone
Telex Communications
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