Electronics Forum | Wed Dec 19 09:23:47 EST 2001 | davef
Bow & twist for bare boards and panels: IPC-A-610 1.5% for PTH only and 0.75% for SMT
Electronics Forum | Wed Dec 04 04:29:51 EST 2002 | CH
U might need to run the board on a reflow pallet with a clamper. This will help to solve the warpage problem on the PCB and connector.
Electronics Forum | Thu Mar 13 19:11:03 EST 2003 | Wes
Does a third solder reflow compromise component and solder reliability? We find that the only way to rework a particular BGA without warpage is to reflow the entire board.
Electronics Forum | Tue May 06 06:29:06 EDT 2003 | yukim
Hi, No, the layout is different, but both have chips located arallel and perpendicularly to the flow direction. And we do have defects in both orientation. What about the PCB warpage? Sometimes we find warped PCBs. Could this affect? Thanks, Yu.
Electronics Forum | Mon Aug 25 20:29:02 EDT 2003 | davef
For further discussion on the "being hosed by the physics": http://www.cooksonsemi.com/tech_art/pdfs/Controlling%20Warpage.pdf
Electronics Forum | Wed May 19 08:18:59 EDT 2004 | davef
Here�s our thinking on the subject: http://www.smtnet.com/forums/Index.cfm?CFApp=1&Message_ID=27586 For further discussion on the "being hosed by the physics": http://www.cooksonsemi.com/tech_art/pdfs/Controlling%20Warpage.pdf
Electronics Forum | Sun Aug 01 11:39:41 EDT 2004 | Andrew
I am seeing high rate of open joint at NexLev connector and also BGA warpage issue with 52 mm Hyper BGA.anyone has the same experience?
Electronics Forum | Fri Apr 08 04:48:34 EDT 2005 | vinitverma
7mils/inch is 0.7% and the IPC-A-610 calls for 0.75% (for SMT), so both are approx. the same. So there are no two methods in what you described. The 7mil/inch is also a percentage. Regards Vinit
Electronics Forum | Fri Apr 15 11:52:09 EDT 2005 | vikkaraja
Part is being pre rotated already and I also changed the nozzle size from 15mm to 17.5mm this morning. There is no board warpage at all and production is watching for it while an operator puts on a barcode label.
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.
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