I remember a Technical Paper published by Amp a long time ago 'Evaluation of
Pin Insertion Techniques to Reduce Board Damage'. If you can lay your hands
on that paper, all your questions should be answered.

From what I remember, square (actually rectangular) pin is not an option for
an .062" board. A minimum board thickness of .093" or better still, .125" is
needed.

Even then, the method consists of forcing rectangular pins into circular
holes and the pins stay in place by the static frictional force generated by
the interference. The hole diameters should be maintained within 0.002"
tolerance (higher costs - as are the stamping costs to close tolerances of
the pins). The troubles are aggravated by the presence of 'creep' of the
board material and the plated through hole with time and temperature.We are
not even talking hole rupture, yet, which is a high possibility considering
the sharp edges and corners of the posts and the human error element of
misalignment while staking the post into the hole!

All the above considerations make interference fit an unreliable process to
be recommended for a brand new design! For an ancient design already in
production for years, one would probably live with it....

That is the reason action pins and other compliant pins have come into
being.

Regards,
Lakshmi Dwivedula

(978) 256 6214

Mail to: [log in to unmask]
----- Original Message -----
From: "Nachbor, Suzanne (MN51)" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Monday, February 10, 2003 2:33 PM
Subject: [TN] Compliant pins in PWB's versus standard square pins


> > We have a new design where an engineer is looking at using square wire
> > wrap pins and press fitting them into a pwb to make the connection
instead
> > of a compliant pin press fit (similar to what is normally used in a
mother
> > board design).   The board will be 062 thick double sided. This pin may
> > also require a rework step which would remove it from the pwb and then
> > re-seat the pin.
> >
> > I'm concerned with this design proposal and the long term manufacturing
> > robustness and reliability.  There has to be some history of why we went
> > to compliant pin designs for press fitting into pwb's.   Can anyone
> > provide me some good data that shows me how reliable a square wire wrap
> > pin press fit into a pwb would be?  Is there some good history of why
> > compliant pins were selected for press fit applications?
> >
> > Suzanne Nachbor
> > Supplier Quality Engineer/Commodity Lead
> > Phone:  763-957-3923
> > Fax:  763-792-2486
> > e-mail:  [log in to unmask]
> >
>
> ---------------------------------------------------
> Technet Mail List provided as a free service by IPC using LISTSERV 1.8e
> To unsubscribe, send a message to [log in to unmask] with following text in
> the BODY (NOT the subject field): SIGNOFF Technet
> To temporarily halt or (re-start) delivery of Technet send e-mail to
[log in to unmask]: SET Technet NOMAIL or (MAIL)
> To receive ONE mailing per day of all the posts: send e-mail to
[log in to unmask]: SET Technet Digest
> Search the archives of previous posts at: http://listserv.ipc.org/archives
> Please visit IPC web site http://www.ipc.org/html/forum.htm for additional
> information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700
ext.5315
> -----------------------------------------------------
>

---------------------------------------------------
Technet Mail List provided as a free service by IPC using LISTSERV 1.8e
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/html/forum.htm for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
-----------------------------------------------------