This is my opinion... of course...

I believe the ideal hole diameter they were trying for in the IPC spec was
calculated with respect to solder wicking and the solder weld meniscus shape
and component lead retention in the hole during wave soldering. I don't
think they added compensation for auto insertion to that table. I do not
believe IPC was even thinking of making any allowances for any particular
Auto-insertion machine... each are different, Universal, Panasert, etc...
The tolerances and requirements of the insertion heads, and clinched lead
cutters are specific to the machine used... You would have to add the
tolerances of your machine of choice to the equation and design to those
criteria rather than the spec sited which does not take that compensation
into account.

Best regards,

Bill Brooks - KG6VVP
PCB Design Engineer, C.I.D.+, C.I.I.
Tel: (760)597-1500 Ext 3772 Fax: (760)597-1510
Datron World Communications, Inc.
_______________________________________
San Diego Chapter of the IPC Designers Council
Communications Officer, Web Manager
http://dcchapters.ipc.org/SanDiego/
http://pcbwizards.com

-----Original Message-----
From: Jon McDowell [mailto:[log in to unmask]]
Sent: Monday, February 13, 2006 2:58 PM
To: [log in to unmask]
Subject: [TN] Hole size specs

Technetters

I have a question for you

We are loading a component with a lead diameter of .032 +/-0.002 into a
hole that is .042 +/- 0.003.

On page 20 of IPC-2222 it states in tables 9-4 and 9-5 that with a
tolerance of +/-0.004 the max over sizing in respect to the lead
diameter (on the min side of tolerance) is +/-.023.  Can anyone explain
the reason behind these numbers.

We are using an Panasonic AVKII which call for the hole to be oversized
0.019 from the maximum lead tolerance.

Why would IPC and Panasonic specs not match, this puts us in a difficult
position.


Any help would be appreciated.

Thank You
Jon McDowell
Electronic Controls Co (ECCO)
833 W Diamond St
Boise Id 83705
P 208 395-8025




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