Electronics Forum | Thu Oct 14 23:01:48 EDT 1999 | Dennis O'Donnell
With loaded boards, warpage can be removed by placing the assembly in a wave solder conveyor pallet as you would if you were going to wave solder the assembly. Place board and fixture in a Blue M forced air oven at 90 C for 30 minutes. Let cool to r
Electronics Forum | Thu Oct 14 20:42:07 EDT 1999 | Jeff Ferry
Grace, As deifned in IPC 7721 Procedure 3.2 Bow and Twist Repair "Bow and twist after soldering shall not exceed 1.5% for through hole PC boards and .75% for surface mount PC boards. The bow and twist shall not be sufficient to cause difficulties d
Electronics Forum | Thu Jan 21 15:24:18 EST 1999 | Terry Burnette
| I have received prototype PBGA (256 pins) devices from | Motorola (actual part number = KXPC850ZT50). These parts seemed very warped on the edges. When I put the part on a plain surface, it rocks quite a bit when I press lightly on a corner. I h
Electronics Forum | Fri Jul 30 17:20:09 EDT 2004 | Francois Monette
A couple of other potential issues are moisture/reflow related issues. This can include internal delaminations inside the component, potentially breaking or lifting the wirebonds. It may also induce warpage where the corners of the BGA will curl up.
Electronics Forum | Mon Jun 18 10:34:40 EDT 2007 | swag
If you are using a fixture/carrier in the oven, make sure that it is not too restrictive on the perimeter of the board/panel. A carrier intended to limit warpage can actually cause warpage if the expanding PCB material has no place to go during refl
Electronics Forum | Thu Jun 08 22:54:31 EDT 2006 | hunghung
Dear all, If a PCB board, 2 mils of core with 1oz copper at the top and bottom, is it a good board to be fabricated? will it be caused warpage during etching for inner layer process? if yes, what is the real factor caused to warpage? How to solve t
Electronics Forum | Mon May 22 09:13:12 EDT 2000 | Wolfgang Busko
Hi Sal, I don�t have the solution to your problems but my first thought is warpage. I�ve seen similar things caused by exessive warpage of PCBs 1,6mm thick sometimes and with 0,8mm and T-SOP 50% showed this symptom. Prebaking and a fixture to counte
Electronics Forum | Sun Jul 24 07:03:33 EDT 2005 | davef
Warpage problem causes * MLB constructions (not homogeneous or unbalanced - too resin rich or poor) * Supplier process capabilities (lamination cycles) * Material selections (usually cheap and dirty), etc.
Electronics Forum | Thu Jul 12 20:20:31 EDT 2007 | seankim10
I�m having problem with PCB with 16mil thickness due to warpage. the board convex up in the middle after 1st reflow. It seams the warpage is caused by CTE mismatch between PCB and multiple TSOP's, which are covering ~80% of the bottom side board area
Electronics Forum | Sat Apr 26 08:18:47 EDT 2008 | davef
Your warpage problem could be caused by change in: * Multilayer board construction (not homogeneous or unbalanced - too resin rich or poor) * Supplier process capabilities (lamination cycles) * Material selections (usually cheap and dirty), etc.
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