Gary WILTSCHECK < [log in to unmask] > said:

>Hi, I need help interpreting an IPC 610 specification!
>This is my first attempt at using the internet, so I'm anxious to see any
>response.

Well happy Thanksgiving and welcome to the superhighway.

>In IPC-A-610 rev B, section 9.1.9, page 95, under the section entitled
>"Solderless Wrap-Damaged Insulation & Termianls":
>
>For FIG 9-20, I feel there's a conflict between what's acceptable and what's a
>defect.  It says its a defect for Class 3 if the "base metal is exposed".
>However, just above that statement, listed Under Acceptable-Class 1,2,3 Item
>B, nicks, scrapes gouges, etc. are okay "not exceeding 25% of wire diameter".

That's in the last (top) turn. The way the tool works is such that the wire
will generally be abraded more on its end as it straightens. That last
couple of millimeters does not curl well between the bit and sleeve.

>I interpret this to mean the accept condition allows up to 25%, while the
>defect condition doesn't allow anything.  Am I missing something?

I would guess that they refer to exposed base metal on the post and/or wire
(class 3), excepting the top turn only. If the wire wrap bit is damaging
the wire plating, it is probably worn or burred. IPC does not specifically
prohibit any exposed base metal for class 1 and 2, but I can tell you if
the post corners have exposed (and possibly oxidized) corners then you
could have a reliability problem. The critical part of the connection is
where the corner of the post digs into the wire as the bit stretches the
wire around the sharp corner. This should produce a gas tight
metal-to-metal connection with the tensile strength of the wire keeping it
that way.

If you have good wire, and the right bit and sleeve in good condition, any
abraision to the wire is probably due to improper stripping.

Call Gardner-Denver and ask them for technical details, they will provide
workmanship standards from their files. BTW, "wire-wrap" is a
Gardner-Denver (Cooper Tools) trademark.

>I would appreciate any advice, by sending to me(Gary Wiltscheck at 3M, New Ulm,
>Minnesota) at:
>
>[log in to unmask]
>
>Thanks in advance!

Welcome, sir.

Jerry Cupples
Interphase Corporation
Dallas, TX