In a message dated 2/23/99 9:42:59 AM Pacific Standard Time,
[log in to unmask] writes:

<< we are getting good gasketing.  We ended up with a squeegee speed
 of 1.5-1.6 in/s (or about 40mm/s)when we were printing boards with one
 20-mil QFP, among various other larger-spaced parts.  We had originally been
 at 0.6 in/s (about 15 mm/s)and having to wipe the stencil every five passes
 to get the stencil to release the paste on the QFP aperatures.  We then
 tried 1 in/s and finally 1.5 in/s.  At these speeds, the stencil had to be
 wiped once out of one hundred passes (for boards with more 20-mil parts I
 may slow it down).  Good enough for me, and the operator had no complaints.
 Now we are ready to run!  I  just wanted to thank everybody for this, and
 past, advice and let you know how it turned out!

 Ryan Jennens
 TelGen Corp.
  >>

Hey Ryan!

     Glad to see things working for you...but ya' know, when I read your
email, I have to admit a little confusion. I don't know if I'm the only one
who's ever been taught this, but I've always understood that the slower the
squeegee speed the better when it comes to printing fine pitch.

     Back when I first started using metal squeegees, I talked to a gentleman
named Mark Curtain who worked at Transition Automation to get his opinion on
how we should go about setting-up the printer to use them, if I needed to
change my stencil spec's, and stuff like that. I remember him telling me that
there was 3 things I needed remember about squeegee speeds; 1). The slower the
better, 2). The slower the better, and 3). The slower the better. (sounds like
he was trying to make a point, huh?)

     Don't get me wrong, I'm not about to question your success with what's
working for you, but I'm just trying to get a grip on why a faster squeegee
speed cuts down on the how often you'll need to clean your stencil. Do ya'
have any sort of theories why that would be? You know how us engineers
are...always questioning sumthin'...

Thanks Pardner!!

-Steve Gregory-

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