Electronics Forum | Wed Sep 29 22:50:57 EDT 1999 | Dave F
| Hi All, | Any one experince BGA-chipset warp about 10-15mil after removing | from PCB? | FYI, the rework temperature for preheat was 170C from room | temperature about 30 seconds, & BGA was removed at temperature | between 190-200C. | Thankyou.
Electronics Forum | Fri Aug 28 15:39:14 EDT 1998 | smd
Does anyone know about the ANSI/IPC PCB warpage standard? What is the best way to determine weather boards are warped or not? What equipment works best? Or, is there a general rule of thumb that is also compliant with the standard? I would like to he
Electronics Forum | Fri Aug 28 16:24:56 EDT 1998 | Dave F
| Does anyone know about the ANSI/IPC PCB warpage standard? What is the best way to determine weather boards are warped or not? What equipment works best? Or, is there a general rule of thumb that is also compliant with the standard? I would like to
Electronics Forum | Thu Jun 25 13:00:41 EDT 1998 | Bill D.
I have a 2-up panel measuring about 8" x 8" with a score for depanel throuch the middle. I see warping after reflow of the panel (bending in/about score line). The board is not framed (i.e., supported) during SMT reflow other than on the conveyor thr
Electronics Forum | Fri Jun 26 09:35:46 EDT 1998 | David S.
| I have a 2-up panel measuring about 8" x 8" with a score for depanel throuch the middle. I see warping after reflow of the panel (bending in/about score line). The board is not framed (i.e., supported) during SMT reflow other than on the conveyor t
Electronics Forum | Tue Jun 30 12:06:04 EDT 1998 | Michael Fogel
| | I have a 2-up panel measuring about 8" x 8" with a score for depanel throuch the middle. I see warping after reflow of the panel (bending in/about score line). The board is not framed (i.e., supported) during SMT reflow other than on the conveyor
Electronics Forum | Mon Aug 04 17:35:08 EDT 2003 | Dean
If you lay a flat edge on the PBGA, it is visibly warped? How much of a warp? 0.001, 0.010, 0.050 what? What is your pcb temperature just prior to entering the spike process (zone or step or what ever you call it)? Is it between 165 and 175 C?
Electronics Forum | Wed Aug 10 13:31:05 EDT 2005 | patrickbruneel
Joseph, In addition to my previous post The reason why the cracks are most visible at the transformer location is due to the weight of the transformer. The stress on the boards is the highest because the weight of the transformer will warp the board
Electronics Forum | Thu Sep 15 11:16:20 EDT 2005 | pjc
Thanks Steve, good point about warped boards, which are common with doube-sided reflow. Centerboard support helps minimize on reflow. We did do modification to the workboard holders to ensure boards are secured. The boards where small enough that war
Electronics Forum | Mon Mar 13 22:29:50 EST 2006 | davef
Warp depends on: * How close the board gets to its Tg during the reflow cycle (the closer you get to the Tg the worse the warp gets) * Amount of copper on each side and the balance between the two * Thickness of the board * Overall length x width * T