Electronics Forum | Tue Aug 17 13:36:17 EDT 2010 | hegemon
Since you have home plated the apts and done solder reduction, I would take a look at your soldering profile. We have run into this before when running no-clean and found that reducing the initial ramp rate to the flux activation was a help in the
Electronics Forum | Thu Mar 11 03:03:26 EST 2010 | grahamcooper22
Hi , Looking at your photo....can I also see a hole in the middle of the joint on the chip component ? Maybe its not just a problem with th ejoint son diodes ? Did you also get mid chip solder balls on chips? If so, I'd almost guarantee the pcb has t
Electronics Forum | Thu Feb 08 12:02:15 EST 2001 | slthomas
After reading the variety of responses, I feel moved to ask if you're you talking about what are occasionally referred to as solder beads (mid-chip solder balls, attached to the waste line of your chip caps and resistors) or the solder balls that ten
Electronics Forum | Fri Jan 14 17:51:37 EST 2000 | Dave F
Dave: Two more things: 1. Let's go backwards, so what changed that suddenly you've realized that "piles of stencils" are causing solder ballig on chips? Are we speeding down the wrong road? Or is this something you lived with and now have decid
Electronics Forum | Mon Jan 17 08:09:05 EST 2000 | Mark Anderson
As stated previous, the following elements all have a effect on solder beading. Solder Paste, stencil apertures(reduction of home plate), stencil thickness, printing parameters, placement height, reflow preheat and soaking slope and dwell, manufactur
Electronics Forum | Wed Feb 16 09:19:22 EST 2000 | MARK ALDER
Please check Circuit Assembly March 1998, article "Solder balls and aperture shapes" and August 1999 "Guiding stencil design". They can be contacted at www.circuitassembly.com The main cause of mid chip solder balls is the volume of paste that is p
Electronics Forum | Mon Sep 19 09:16:24 EDT 2016 | markhoch
Hi Shriram, Are you saying that there is a trace running between the pads for this 0603 capacitor? If so, this design may be causing a gasketing issue between the stencil and the PCB. The uneven height prevents the stencil from sitting flat on the PC
Electronics Forum | Tue Feb 13 07:26:26 EST 2001 | doctord
Bill, I can give you suggestions. First and foremost. Print a board and look under a microscope. Are you printing exactly on the pads? If you print on the mask, no matter how good we got the profile, no matter what paste we would get solder balls. Mo
Electronics Forum | Fri Jan 14 16:58:20 EST 2000 | Dave F
Dave: You're probably correct about too much paste, given that your balling is congrigated near the center of the chips. Three things to consider: 1 Lower temperature profile @ front 3 zones 2 I've heard some stencil suppliers can plate addition
Electronics Forum | Fri Jan 14 17:24:08 EST 2000 | John Thorup
Yeah, it would be kind of expensive to replace all of your stencils but it's the only real answer. Be sure that all your new and replacement stencils have a home base or home plate shape for the passives. This reduces the paste volume near the cent
