Scott,

PEM fasteners that might be used for printed circuit boards have two
"attributes".  When pressed into an unplated hole they show what appears to
be measling.  When pressed into a plated hole they tend to rip the plating
out of the hole.  Neither of these is a happy situation.

We use standard swage standoffs with a Cambridge Automatic AE2000 press.
http://www.cambridgeautomatic.com/  I have special die sets for the
different lengths, but most use the same top "roll" die.  My operators are
the ones to change the tooling and usually the only problem they find is
that I haven't done my periodic maintenance to lubricate the ram shaft.

If the die set you are using is not correctly formed or is a flat you will
get cracking.  Also these standoffs come in different sizes for different
thickness boards.  Our standard board thickness' are 0.062" and 0.090".

The nice thing about the Cambridge Automatic system is that the machine
controls the "stop point" by using a NOT valve which detects the lack of air
returning from the ram.  When this point is reached it reverses and opens
up.  With this feature I can, for example, use the same die set for both
1/4" and 3/8" long standoffs using the same machine setup.

Regards,

Phil Nutting
Manufacturing Engineer
Kaiser Systems, Inc.
High Voltage Power Supplies That Work(tm)
126 Sohier Road
Beverly, MA 01915
ph: 978-922-9300
fx: 978-922-8374
www.kaisersystems.com
[log in to unmask]


-----Original Message-----
From: Rougeux, Scott [mailto:[log in to unmask]]
Sent: Thursday, March 29, 2001 12:04 PM
To: [log in to unmask]
Subject: [TN] Stndoffs


Good Morning,

Does anyone know of a supplier for standoffs were the standoffs are indexed.
We are currently using a press to insert them. The press flares over the
bottom of the standoff...Due to the multiple sizes of standoffs we use
repeatability becomes an issue. If the setup is incorrect the standoffs can
crack or break at the base causing them to be loose. I was wondering if
anyone was aware of a standoff that may be index or stepped...sort of like a
pem nut. This way we could just press them into the board without have the
concern with the flare.

Thanks in advance.

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