Electronics Forum | Tue Sep 14 16:23:54 EDT 2004 | dan
What is your cure time for the mask?
Electronics Forum | Wed Sep 15 22:43:24 EDT 2004 | davef
Just to help convince those on the fence that we don't know dip: 2221A, 4.5.1 tells you the vias have to be tented on both sides.
Electronics Forum | Wed Sep 15 22:52:58 EDT 2004 | pdeuel
We had same problem. Solder balls appeared on top side of board and led to damaged second side stencles. We worked around problem by running blank boards thru oven and inspecting and removing solder before processing boards with parts.
Electronics Forum | Thu Sep 16 15:01:13 EDT 2004 | russ
You may want to either open up the bottom of the vias so they will not "volcano". Or you will want to seal both sides. It never works having one side of the vias masked and the other open with HASL. Russ
Electronics Forum | Sat Sep 18 08:26:10 EDT 2004 | davef
Carol: If you would have problems both covering the via and keeping mask from the BGA pads, maybe you via are too close to the pads. Maybe some of the IPC pad design guidelines would help.
Electronics Forum | Thu Sep 16 18:59:14 EDT 2004 | Carol
Thanks Everyone, the information was very useful. We use 7095 as a bible. A-610 6.5.3 doesn't allow for any solder balls not entrapped/attached etc. so we will look again at plugging/tenting both ends of the via. We ran into the problem of the mask
Electronics Forum | Tue Sep 14 14:52:22 EDT 2004 | Carol
During processing, the solder in the vias reflows and forms solder balls. PCBs have solder in random PBGA vias from the board manufacturer.The manufacturer says this is a result of the HASL process and is unavoidable. We use HASL finish, multilayer,
Electronics Forum | Tue Sep 14 19:47:16 EDT 2004 | davef
use something other than HASL. "The rest of the world seems to be processing with no problems..." [Hello!!! Earth to Carol. This is a test.] Things you are considering could be more trouble than they�re worth. "1) Reduce via hole size" [If you re
Electronics Forum | Mon May 18 08:18:53 EDT 2020 | derekjeter
I think it concerns peeling electrostatic potential,and it will get lower throwing rate.
Electronics Forum | Wed May 31 21:33:52 EDT 2006 | jacksaria
Hello jbrower, Thank you for the feedback. Actually, our main problems is the pick and throw. Whats your suggestion how to control the pick and throw?What are the factors that affecting pick and throw?How to reduce the sources of variance at each st
