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January 1997

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Subject:
From:
[log in to unmask] (Jack Crawford)
Date:
Tue, 21 Jan 1997 15:13:04 -0500
Content-Type:
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Following is additional information from the EMPF HelpLine in Indianapolis,
prepared by Jim Moffit, IPC-A-610 Master Instructor and member of the 610
Technical Committee:

"Lifted pads are mentioned by IPC-A-610, but not were you would expect.
The only reference is found in the Mechanical Assembly section (see Figures
2-65 & 2-66) where any land lifted in excess of 75% is a nonconforming
defect (Classes 1 & 2) and any lifted land is a defect for Class 3.  In
using the criteria of A-610 be careful to differentiate between a
functional and non-functional land area as the criteria is different.  The
next revision of 610 (presently in-process) will expand and redefine the
lifted land criteria.  The ANSI/J-STD-001 defines a lifted land as a defect
if the land is lifted more than the thickness of the land material.  Note
that basic lifted land criteria are also identified in IPC-A-600
(Acceptability of Printed Boards) which says "Nonconforming defect (Class
1, 2, 3) - Lifted land as received.  No lift allowed from the laminate
surface plane to the bottom surface at the end of the copper land, whether
or not resin appears on the copper land."  Be advised that the criteria of
A-600 should be applied only to brand new (unsoldered) pwb's and that
(depending on Z-axis Tce) some degradation and lifting of lands can be
anticipated during the assembly soldering process, that is why the
J-STD-001 has a more liberal criteria.    Regards, Jim Moffitt/EMPF"
>
>
>At 03:27 PM 1/14/97 -0500, you wrote:
>>>Resent-Date: Tue, 14 Jan 1997 03:05:53 -0800
>>>Resent-Sender: [log in to unmask]
>>>Old-Return-Path: <[log in to unmask]>
>>>Date: Tue, 14 Jan 1997 10:52:18 +0200 (IST)
>>>From: Yakov Steinberg <[log in to unmask]>
>>>To: [log in to unmask]
>>>Subject: lifed pads
>>>Resent-From: [log in to unmask]
>>>X-Mailing-List: <[log in to unmask]> archive/latest/9179
>>>X-Loop: [log in to unmask]
>>>Precedence: list
>>>Resent-Sender: [log in to unmask]
>>>
>>>Fellow Technetters:
>>>
>>>What is the "rule" regarding lifted pads on multilayer boards?  We have
>>>always scrapped them.  A subcontractor recently returned a few of our
>>>boards which had lifted pads.  We follow IPC-A-610B class II.  The subject
>>>is not mentioned.
>>>
>>>
>>>Comments are appreciated.
>>>
>>>Ellen Berkman
>>>Excalibur Systems

***ALL NEW EMPF PHONE NUMBERS***

Jack Crawford, HelpLine Coordinator
Electronics Mfg. Productivity Facility
****NEW--317.655.3688
****FAX  317-655-3699
714 N Senate Ave, Suite 100
Indianapolis IN  46202-3112
VISIT OUR HOME PAGE AT: http://www.empf.org
[log in to unmask]


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