Hi Thad,

Good to hear from you on the net. In interpreting this requirement, I have always differentiated between thermal stressed and finished boards. I consider "after thermal stress" as having been previously submitted to a temperature of 500 degrees F.  I do not think anyone submits their printed circuit boards to that degree of stress except for testing purposes. Therefore, I conclusion has been that you should not see lifted lands on a section that has not been stressed and if you do see lifted lands after stress, it is not rejectable. The finished board would be represented by the unstressed section.

Just my two cents. I hope I've been looking at this correctly.

Ed Cosper
Director Quality Assurance and Engineering
Graphic Electronics Inc.
Tulsa, Ok

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From:  Thad McMillan[SMTP:[log in to unmask]]
Sent:  Tuesday, August 05, 1997 2:01 PM
To:  [log in to unmask]
Subject:  [TECHNET] FAB:  IPC-6012 & Lifted Lands

     I am confused at what the current IPC-6012 states regarding Lifted
     Lands:

     -------------------------

     Page 11:

     3.6.2.9 Lifted Lands  Lifted lands are allowed after thermal stress
     provided that the visual criteria of section 3.3.4 are met.


     Page 6:

     3.3.4 Lifted Lands The Finished board shall not exhibit any lifted
     lands

     -------------------------

     In the old IPC-RB-276 lifted lands was permitted after thermal stress.

     Is this an error in IPC-6012 or has there been a change in what is
     acceptable?

     I'd appreciate any feedback.

     Thanks,

     [log in to unmask]