Electronics Forum | Thu Aug 22 22:58:40 EDT 2002 | craigj
Are having problems with cheap paper phenolic pcbs that appear to have shrunk. That is they no longer match the stencil (stencil is correct). Some people seem to think this is normal, is there an industry standard out there that says what is reasonab
Electronics Forum | Sat Dec 08 14:11:47 EST 2012 | eniac
I don't know what is BOC (may be I know it by another name...), but: 1. Check placement coordinates by camera (if your mounter can do it) and tune it if they have a problems; 2. Check your stencil - it can be a mistake during stencil cutting (very sm
Electronics Forum | Thu Apr 11 19:12:11 EDT 2002 | djarvis
Sorry fellas -disagree. We only clean our stencils in the ultrasonic machine at the end of the run. If the same pcb is up the next day we clean them by hand. We use Electrolube SSS and the used rolls from the in line under stencil cleaner. Wipe the
Electronics Forum | Mon Feb 18 11:31:02 EST 2008 | davef
Print paste through the new stencil with a piece of mylar [or other clear plastic sheet about the thickness of paper] between the board and the stencil. Dispose of the mylar according to local practice after confirming proper aperturation of the sten
Electronics Forum | Tue Apr 10 08:37:36 EDT 2018 | davef
Hi Steve ... I found nothing in the manufacturers "paper" to help. Comments are: * I agree. No blobs. Solder on the thermal pad should me minimized. Too much solder will float the component. Old timers used to talk about 50-80% coverage. * If you'
Electronics Forum | Thu Sep 06 22:49:35 EDT 2018 | cmchoue
Dear davef, All of this are takling about how to improve release solder paste, Area ratio, aspect ratio...etc, but i want to learn the "When design BGA stencil which the safe air gap between solder paste in difference stencil thickness", this can he
Electronics Forum | Thu Sep 06 05:25:38 EDT 2018 | spoiltforchoice
I'm no expert but I think you will find the majority of discussions around BGA & good printing results focus on the PCB design and things like tented vias and pad definition. e.g https://macrofab.com/blog/bga-pad-creation-smd-nsmd/ After that, work
Electronics Forum | Thu Sep 06 11:24:56 EDT 2018 | davef
pdf "BGA Stencil design guideline for avoid bridge" As you would expect, Google found 40,000+ results in less than a second One of my favorites was Power Point Presentation by Greg Smith [gsmithATfctassembly.com] at FCT Assembly: "Improve SMT Assem
Electronics Forum | Thu Sep 06 03:43:00 EDT 2018 | cmchoue
Dear Experts, Have any paper or data talking about the design guideline for avoiding BGA solder bridge? I desire to know the rule(guideline)that compare difference stencil thickness and safe solder design distance (air gap) can avoid bridge.
Electronics Forum | Fri Sep 07 04:19:59 EDT 2018 | spoiltforchoice
You have lost me, its a stencil, you can change the aperture size, you can change the thickness and you can change the walls of the aperture. And all of those things will be in the papers anyone can find with a google. I have no clue what safe air g
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