Electronics Forum | Tue Sep 01 20:36:05 EDT 1998 | Rin Or
| We are experiencing shorting on a BGA. The part has a 1mm pitch with a 196 I/O count. The problem seems to pop up without warning & disappear in the same manner. | Our pad design is .020" diameter pads with .025" solder resist diameter. The ce
Electronics Forum | Tue Sep 24 12:49:43 EDT 2002 | dragonslayr
Aperture reduction @ 5 mils thickness is your best bet. It may take several attempts to get just the right paste volume. What aperture reduction was specified to the stencil house for these specific LEDS? or was the stencil blindly produced using a
Electronics Forum | Wed Nov 02 04:28:58 EST 2005 | Simon
Hi James, I have worked in many SMT sites and this is not an uncommon practice. It is true that print deposit consistency will improve after the first few prints as the aperture walls become lubricated, but with modern stencils/paste and a well-desig
Electronics Forum | Tue Oct 03 16:40:28 EDT 2006 | slthomas
It's a consignment kit and we already have the parts. Otherwise I'd tell them to panelize the thing and we could build all 30 in one pass. I may be able find a 25 mil QFP on a stencil and hand print that one part if the apertures are long enough. D
Electronics Forum | Wed Dec 15 18:03:28 EST 2004 | russ
I have used both 4 and 5 mil stencils for 10 mil round apertures. We don't have volume measurement capability but we measure height and the 4 mil appeared to have more paste and better uniformity from a visual standpoint than the 5 mil. The unfortu
Electronics Forum | Wed Sep 27 13:45:35 EDT 2000 | Bill Schreiber
Dear Dreamsniper, A big hidden cost in any cleaning system is the cost of diminished production and rework. I assume you are cleaning the adhesive stencils manually since there is no equipment cost in your formula. Manual cleaning of adhesive sten
Electronics Forum | Thu Jan 31 15:13:20 EST 2008 | chef
You will need to develop your reflow profile which includes drilling a hole through the fab and into the ball for accurate temp measure. During profile/process development you will probably want 3D x-ray (consider contracting that out). Once in prod
Electronics Forum | Thu Mar 29 12:05:38 EDT 2007 | cecil
OK, just finished our prototype build. PWB 7.5" x 10" 16 layers smallest pitch 17mil smallest BGA pitch 30mil (round apertures) smallest component 0402 total of 1492 placements 5 mil stencil foil (invar) Had numerous PQFN packages that always gave
Electronics Forum | Thu May 24 08:55:25 EDT 2007 | ck_the_flip
Here's some quick things to look for: 1. Does your solder paste feel like concrete, does it roll-up into your squeegee blades, and stick to your stencil? If so, your problem is the solder paste. The mixture of powder and flux, or metal load is ou
Electronics Forum | Mon Apr 25 06:34:29 EDT 2016 | spoiltforchoice
I'm going to ask the obvious question first. Why can't you place the entire job the same day you paste it? Getting a sensible workflow is a far better method of improving productivity than experimenting with crazy solutions. I can see a gas atmosphe
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