The Following is a text-only cut-and-paste from our De-warping Procedure for anyone
interested:  I apologize to the person requesting this information.  I inadvertantly deleted his
email before getting his address.

DEWARP PROCEDURE
De-warping shall be accomplished using the Press Area oven as the primary tool. If it is
unavailable, the Screening Area oven may be used as a backup.
All de-warping must be coordinated with the Press Area operators to ensure that press
schedule is not compromised. If there is a conflict of order priority, the final decision will be
made by the Process Owner.
STACKUP PANELS
Place the Oven Shelves no lower than the 4th slot from the bottom to prevent them from
coming too close to the heating elements.
Stack panels to be de-warped (maximum 4 high), using the following configuration.
DO NOT PLACE ANY WEIGHT ON TOP OF STACK!
BAKE THE STACKUP
If using Press Area oven, preheat to 325°F.
If using Screening Area oven, preheat and verify oven setting of 300°F.
Place stack-up inside preheated oven.
Bake for (4) hours.
After (4) hours, shut down oven.
Allow panels to cool slowly inside oven with doors closed, to below 120°F. before removing
them from the oven. IT IS EXTREMELY IMPORTANT THAT PANELS COOL SLOWLY!
Remove panels from oven.
RE-MEASURE FOR BOW AND TWIST
Re-measure for Bow and Twist using the criteria in the previous instructions.
Fill out a Discrepancy Report to MRB any panels that do not meet the bow and twist
criteria.
Complete the Log Sheet and indicate how many panels were MRB (scrapped) AFTER
de-warping.
MARKING DEWARPED PANELS THAT HAVE MET THE CRITERIA
Using an electric engraver, scribe a ¼" letter "W" within a ½ inch of one of the
auto-insertion holes (not slots) on the carrier frame.
Mark the letter "W: on the Circuit 1 side only.
Do not make any marks on the actual PCB (part). Mark the carriers, only.


Fred J. Paul, Staff Engineer, PCB Operations
FLUKE Corporation, P.O. Box 9090, Everett, WA 98206
VOICE:  425 356 5734    FAX:  425 356 6070, [log in to unmask]

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