Electronics Forum | Thu Oct 26 08:59:56 EDT 2000 | Antonio A. Medina
Ok guys, I need help. Here's the deal. We're getting micro solder balls under discreets on the bottomside of the board. Here's my set up... MPM screener w/vacuum plate 6 mil metal screen with 90% circular (rounded) apertures 7 mil (measured) past
Electronics Forum | Fri Apr 29 14:16:16 EDT 2011 | ppcbs
Below is the long explanation. This defect is most commonly found with BGA components, but can arrise with all components. I see it happening more now with lead free boards that are being assembled with a no clean flux. Best short term remedy is t
Electronics Forum | Tue May 22 11:03:11 EDT 2007 | Michelle
We now have an AOI in our process after printing and have noticed that all the small aperatures are getting clogged by solder paste. Mainly on all fine pitch parts. We are using Kester ws R562 SN63/PB37 mesh -325+500 90% metal. It was manufactu
Electronics Forum | Wed Apr 21 11:33:20 EDT 2004 | tigerlordgm
As one of our small batch processes, we place BGAs on PCB without using solder paste. We apply tacky flux to a predetermined height on a pallet, "dip" the BGA into the tacky flux to wet the solder balls to the set height, and then use a BGA rework st
Electronics Forum | Tue Oct 14 11:34:04 EDT 2003 | Axl
As far as solder paste goes search no further! I have worked for some huge CM's as a Process Engineer and a lot of them have put thousands of hours of Engineering time and evaluation just to come up with the same answer every time. For no-clean it is
Electronics Forum | Fri Jul 06 13:44:15 EDT 2007 | shrek
Krikies! seems like a head-scratcher if I may say so me-self. I would say the other ogre is right, that surface finish will play a big factor in your solder joint's grain structure or how shiney 'tis. Non-HASL bearing finishes will typicaly exhibit
Electronics Forum | Wed Jan 07 00:18:14 EST 2009 | milanrit
Recently on one of my assemblies(sn/pb) I started seeing leaded BGA failure at functinal test for opens, but when I inspected them through 5DX and ERSA Scope it doesnt seem like there is any opens or insufficient and half no. of boards passed functio
Electronics Forum | Wed Oct 09 16:43:50 EDT 2002 | mjz289
Kester 256 has also worked tremendously well for us. We have soldered thousands of BGAs from 156 balls to 780 balls .8mm pitch with no solder problems (shorts,opens or voids) and no residue problems. Give it a try.
Electronics Forum | Fri Oct 28 07:31:37 EDT 2005 | avalancher
I have always encountered problems when using Kester (everything from bad solder to solder balls). I have profiled the boards to the extreme thinking it was my reflow recipie, but with no luck. I ended up going to AIM and I have never had a problem s
Electronics Forum | Wed Jan 31 17:04:22 EST 2001 | williamh
Hello all, I am having a problem with solder balls on chip resistors and chip capacitors. I have searched the archives and found some information concerning solder balls but have a couple more questions. 1. What is the realistic industry standard f
