Electronics Forum | Wed Apr 27 07:16:40 EDT 2005 | jdumont
Thanks a lot guys. The part dims are in mm by the way. So last night i was looking at the .pcb file and saw that the pad size and stencil are both .013" while the ball on the BGA is .018" (sorry for switching from metric). Is this ok or can i have en
Electronics Forum | Fri Jan 17 09:38:20 EST 2003 | Grant Petty
Hi, We have a BGA that uses .4mm diameter PCB pads on the BGA itself, however we have decided to use .5mm pads on the PCB, to help paste release from the stencil. Is this a bad thing, having different size pads on the PCB compared to the BGA itself
Electronics Forum | Thu Jan 24 19:57:40 EST 2002 | davef
Are there formalized standards for the properties of solder balls? No Get IPC-7095 �Design & Assembly Process Implementation for BGA's�. General comments about array package solder balls are: * Ceramic packages use harder solder, like 90/10. * Pla
Electronics Forum | Tue Apr 13 14:14:59 EDT 2004 | russ
I have actually printed this same condition with type 3 paste Alpha WS709. I posted this for discussion and cannot remember what I called it. We did need to clean the stencil after every three prints. I did not check volume on these locations but
Electronics Forum | Thu Nov 09 23:01:34 EST 2006 | davef
Tin/lead alloys tend to oxidize very easily, affecting solderability. Use the largest particle sized paste possible, because as the particles decrease in size their total surface area per unit mass increases, effecting: * Demands on the flux increase
Electronics Forum | Wed Apr 14 08:15:18 EDT 2004 | arcandspark
We have tried other stencils with different size openings but this company will not allow us time or money to run any experiments to define stencil criteria and printer settings, its just run, run, run. They really dont care about post reflow yields.
Electronics Forum | Fri Feb 20 13:01:26 EST 2004 | Jay
First, it depends on the alloy composition of the solder. As you might know, eutectic Sn/Pb solder has the lowest melting point among available conventional solder systems. (except those based on Sn-In and Sn-Bi systems.) For example, 63Sn/37Pb - 183
Electronics Forum | Wed Apr 27 12:26:49 EDT 2005 | jdumont
Square you say? Wouldnt this give less paste deposition than a circle and basically reduce the standoff height the same as making the pad bigger? Would using a type 4 paste for this size stencil aperture (.013") be a good idea? Thanks JD
Electronics Forum | Fri Apr 29 07:09:10 EDT 2005 | jdumont
Really you think the 256 is the issue eh? I have some a sample of the type 4 powder size coming in hopefully today. Hopefully that will help, if not its back to the old solder eval drawing board. I love my job...
Electronics Forum | Wed Apr 27 02:22:08 EDT 2005 | grantp
Hi, There are a number of things you can try. You are already using 1:1 hole to pad ratio, and that's good as you need the size. I would try an electroform stencil as that will have a smooth side of the aperture and help paste release. Don't use c
