Electronics Forum | Wed Dec 09 07:48:23 EST 1998 | EFData
Does anybody out there have any special insights into utilizing no clean paste in high frequency RF applications? I would imagine there may be some issues with solder balls that would affect functional test (Earl, do you have something for me here?)
Electronics Forum | Thu Jun 18 09:26:38 EDT 1998 | Maurice McClain
WHAT SHOULD THE RATIO BE OF STENCIL APERATURE TO PAD TO GET GOOD QUALITY RESULTS. BY THAT I MEAN, A MINIMM OF SOLDER BALLS, AND LITTLE TO NO BRIDGING, SHORTS, ETC.. RIGHT NOW WE ARE USING A 1:1 RATIO, BUT ARE INVESTIGATING REDUCING THE APERATURE S
Electronics Forum | Wed Nov 21 21:50:50 EST 2001 | Glenn Robertson
Tony, What you are seeing can occasionally be caused by gaps in the plating of the blind vias. If they are not "airtight" you can get moisture coming from the laminate that shows up as voids in the solder balls. You might check on the board sup
Electronics Forum | Tue Mar 05 22:34:27 EST 2002 | YoYo
You better be careful how you plug vias at screenprint - we currently have a customer that wants vias plugged, so we had a 2% aperature reduction so we would not have to much paste, I believe it should have been reduced more because some of the solde
Electronics Forum | Thu Jul 18 21:56:40 EDT 2002 | computer
Hi Dave, I read the same article as you. But that method leaves solder balls in via holes or traces of it remains on the boards. I am using ultrasonic with solvent for cleaning misprint boards. Apprarently, they have adverse affect to the en
Electronics Forum | Sat Sep 07 06:57:33 EDT 2002 | mk
I agree but, are there really heavy metals in this water? Our process is as follows. Print Paste Reflow Board (no components, water soluble paste only) Wash Board Same reflow profile for almost every order so no solder balling issues etc. Carbon an
Electronics Forum | Wed Jul 23 08:21:55 EDT 2003 | James
Here we go again. I tried changing paste and that did nothing. Literally solder balled up and flew to the next pad. What would be a short term fix to use up all baards with white tin. Is there a fix if the board house did not manufacturer the boards
Electronics Forum | Wed Mar 24 15:10:23 EST 2004 | davef
Without a proper picture, I'd reject the parts that you describe based on IPC-A-610, 7.2, which says words to the effect: Defect - Class 1,2,3 - Dirt and particulate matter on assembly, eg, dirt, lint, dross, metallic particles, etc. Absence or pres
Electronics Forum | Tue Apr 13 08:19:52 EDT 2004 | arcandspark
The PCB's we are seeing the voids on are made of some material called Thermount, not FR4. The pads are very easily pulled off if any touch up or rework is done. The voids I am seeing are (hugh) 50% to 75% of the Solder Ball volume. The last new batch
Electronics Forum | Wed Apr 28 12:10:14 EDT 2004 | paul_bmc
Are your solder balls after reflow a perfect sphere or are they oblong, like chushed. I know a heavy bga or incorrect reflow profile could cause bridging. Also too much flux paste. Sometimes what we do is brush the flux paste onto the pcb pads inst
