Electronics Forum | Thu Sep 05 03:23:14 EDT 2002 | manic
Hi, I encountered a problem with pbga. One edge either warp downwards or upwards creating bridging or open. This pbga have fr4 at the bottom (compound molding at the top). The fr4 is bigger than the top compound by 3mm at each edge. Pls help. Than
Electronics Forum | Tue Sep 10 08:22:36 EDT 2002 | davef
I doubt that the interposer is FR4, it's more likely to be BT. Warp during reflow is a function of material a reflow recipe. Your ramp is too fast and is causing the interposer to bend like a potato chip.
Electronics Forum | Wed Sep 11 16:57:04 EDT 2002 | bigwop
I've seen this problem caused by the cool down. > On a 7 zone oven I made a profile to peak at zone > 5 to give some semblance of control to the cool > down. The component can develope a big delta T, > because of the difference of materials Che
Electronics Forum | Wed Sep 11 13:20:37 EDT 2002 | stepheno
I've seen this problem caused by the cool down. On a 7 zone oven I made a profile to peak at zone 5 to give some semblance of control to the cool down. The component can develope a big delta T, because of the difference of materials
Electronics Forum | Wed Sep 11 23:20:44 EDT 2002 | scottefiske
Profiles are absolutely the first course of action to validate. A few additional questions would be: * Moisture can cause warping as well, verify the manufacturers recommended handling procedures were followed. * Where is the suspect BGA located
Electronics Forum | Mon Feb 13 23:05:02 EST 2017 | swestheimer
I have been asked a very good question but have not been able to find a good answer. IPC for both PCB and PCBA refer to the X & Y dimensions to measure warp and twist but how would you determine the warp and twist for a round PCB or PCBA?
Electronics Forum | Tue Feb 14 22:20:10 EST 2017 | swestheimer
Hi Dave, Thank you for your inputs as they were good suggestions. I however let out one important detail and that this is IMS material and not glass reinforced so I think that there is more bending going on during processing than warping and twistin
Electronics Forum | Tue Feb 14 09:10:43 EST 2017 | davef
Assuming the traces run parallel and perpendicular to each other, I'd choose one direction the traces run as "x" and the other direction for "y." Then I'd pick a unique identifier on the board to insure proper orientation. Next, I'd measure warp and
Electronics Forum | Tue Jun 25 01:01:15 EDT 2002 | ianchan
Hi mates, has anyone ever done a DoE on the degree of warp PCB, after a SMT Reflow process? what were the findings and conclusion based on such a DoE? which were the critical (DoE) factors that influence the degree of warp PCB? any optimal reflow se
Electronics Forum | Wed Jun 26 08:53:32 EDT 2002 | davef
We have not done a DOE on board warping. Consider: * How close the board gets to its Tg during the reflow cycle * Amount of copper on each side and the balance between the two * Thickness of the board * Overall length x width * Time at temperature
