On 18 December, Paul wrote:
>> Can anyone refer me to a stencil vendor who provides "reusable frames".
>> I am referring to the type as to where you only need to buy replacement
>> foils, and not the not the rigid alum. frames.
>> My goal is to reduce the stencil cost that are passed along to my customers.
>> We are a "proto-type to med volume ass'y house" and we go through quite a few
>> stencils as new revisions of boards are generated.
Thank you,
Paul Peltier
SMT MANAGER
Paul,
I know what you are talking about, there's two manufacturers of custom frames
that you use to mount the foils that I've seen. The one that I know for sure is
available is what's called a "Quick-frame" sold by what used to be known as
Screen Manufacturing Technologies in Santa Clara, California, their phone number
is (408) 562-2033. They've recently been purchased by Alpha Metals, but I think
they still call themselves Screen Manufacturing Technologies until after the
first of the year.
SMT's frames are made with two of the parallel sides having a kind of cam
acuated type of tensioning mechanism that is tighten by a series of large screws
along the length of where the foil is placed. The frame is made for whatever
kind of printer you have, below is kinda' how a Fuji frame would look like:
__________________________________________________________
| ______________________________________________________ |
| |_ _| |
| | | | | |
| | |--------------------------------------------------| | |
| |0| Foil |0|<|---Tightening screw
| | | | | |
| |0| ||||| ||||| ||||| ||||| |0|<|---Tightening screw
| | | | | |
| |0| ||||| ||||| ||||| ||||| |0|<|---Tightening screw
| | | | | |
| |0|<-----------Foil Tensioning Mechanism------------>|0|<|---Tightening screw
| | | | | |
| |0| |0|<|---Tightening screw
| | |--------------------------------------------------| | |
| |_| |_| |
| |______________________________________________________| |
|__________________________________________________________|
|
|
"Quick-Frame"
The frame is pretty heavy-duty, I believe it's made of steel, but the one
negative thing that I've heard about it is that it only is providing the tension
at only two parallel sides of the foil. That's not a big deal if all you're
printing is some 50-mil pitch stuff, but if you're doing fine pitch, having
tension only on two sides causes the foil to not behave properly if you're doing
something like a controlled separation rate after the print stroke to improve
the print definition...it just don't act the same as having tension all around
all four sides like a polyester mesh does.
The other manufacturer of frames where you change the foils I saw down at
NEPCON West this past year. It's kind of a partnership type of deal with DEK.
It's called a "Vector Stencil" and it mounts into what's called a "Micro-Mount"
frame. The frame is based on the same principle as SMT's "Quick-Frame", BUT, it
applies tension from all four sides. It does it with a slick little pnuematic
type of system. You plug an air-hose into the frame, lay the foil down on this
type of jig, put the frame on top of it and step on a foot-pedal and it snatches
the foil and applies tension almost all at once. You pop off the air hose and
yer' ready to fly.
When I talked to the DEK people about it, the deal with the Vector stencil
and Micro-Mount frame, was that they were just then trying to get their foot in
the door here in the states. They're trying to license stencil vendors with the
rights to do the stencils and market the frames.
The last I heard UTZ and Photo-Stencil might be doing them now. The point
of contact for the Vector and Micro-Mount is a Martin Wyeth, he can be emailed
at: [log in to unmask] I even think DEK's Web page has something about it too,
it's at: WWW.DEK.COM
__\/__
. / ^ _ \ .
|\| (o)(o) |/|
#------.OOOo----oo----oOOO.-----#
# Steve Gregory #
# SMT Process Engineer #
# The SMT Centre Incorporated #
# [log in to unmask] #
#________________Oooo.__________#
.oooO ( )
( ) ) /
\ ( (_/
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