Electronics Forum | Wed May 29 14:42:53 EDT 2002 | jaltland
I have another question about bga's and stencils. We were told by a manufacturer to use .012 square apertures for .009 dia balls. The original pick & place and reflow goes pretty well (over 95% good), however when we have to select components on th
Electronics Forum | Wed Dec 14 23:32:19 EST 2005 | jhernan9
Hi, I'm having a lot of problems with BGA's shorts, we are using 0.005" stencil aperture 1 to 1 (0.014)", the paste is centre (I can not measured the height)was verified using electronic microscopie, the placement is centre (I'm using local fiducials
Electronics Forum | Tue Sep 14 02:46:17 EDT 2010 | grahamcooper22
Hi Gani, Looking at the pictures in the report it looks as if there is a thin coating of solder on the pcb pad....but it looks like the BGA sphere was barely in contact with the pad. This could be caused by insufficient solder paste on this pad...may
Electronics Forum | Mon Aug 17 02:50:44 EDT 1998 | Bob Willis
| Have an SRT w/preheat, 18 layer board all copper, 456 BGA needs to be removed and replaced. The manufacturer is Chip Express and during reflow it warps up or down. Causing either opens or shorts on the corners. I was using gel flux with multiple
Electronics Forum | Fri Jan 17 15:36:23 EST 2003 | davef
How do 0.5 mm pads on the board help paste release from the stencil? Paste release from the stencil is a function of: * Paste * Printer operation * Stencil design You have no obligation to made your stencil apertures the same size as the pads on yo
Electronics Forum | Wed Sep 22 21:23:03 EDT 1999 | se
| | I've had some trouble pasting a test board for a MicroBGA trial. Most of the paste remains in the stencil apertures. | | The stencil is 6 mil thick, laser cut and electo-polished. | | The apertures are 12 mil in diameter with 20 mil pitch. | | We
Electronics Forum | Thu Sep 23 12:47:48 EDT 1999 | Earl Moon
| | | I've had some trouble pasting a test board for a MicroBGA trial. Most of the paste remains in the stencil apertures. | | | The stencil is 6 mil thick, laser cut and electo-polished. | | | The apertures are 12 mil in diameter with 20 mil pitch.
Electronics Forum | Thu Jul 17 08:17:50 EDT 2008 | edmaya33
5 mil stencil.instead of round, use diamond aperture. RSS profile @ 215�C peak temp on balls(Sn/Pb), with a total of 3.5 minutes profile lenght.Ramp rate at 1.7�C/sec from ambient to 160�C. Consider also good cooling system on reflow. If rework proc
Electronics Forum | Tue Sep 14 14:07:45 EDT 2010 | grahamcooper22
Hi Gani, HASL is normally very good for solderability providing there is a good consistent coating of HASL on the pcb pad. But it is not unusual to have a very thin coating of HASL on the pad and this is poor for solderability. You then have tin/copp
Electronics Forum | Wed Mar 18 11:27:24 EDT 2020 | slthomas
I am about to order a stencil and I can already see that I'm going to have issues. I'm hoping someone has a recipe for this scenario that we haven't tried yet. The parts are 16 mil pitch bga's, the pads are NSMD (10 mil dia. with 12.6 mil mask open
