Electronics Forum | Fri Sep 10 14:32:49 EDT 1999 | John Thorup
| We have a product, with various PWBs, with over 600 parts each one (We are a low Volume/high mix company with an average component placement per PCB between 250 to 300 parts). This PWBs have 7 to 10, 20 mils pitch parts. We are having problems with
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 Jul 24 17:47:16 EDT 2000 | John Thorup
Hello Nick I'm not aware of any published 1:1 footprints. couple of options: Topline dummy show and tell display cards. $$ I believe. Since there aren't that many different pitches, get one of each and glue those puppies to a card. Could be new, dea
Electronics Forum | Sat Dec 11 12:15:21 EST 1999 | Steve Thomas
We have a pretty challenging board (2-up panel, 15"x20", 48 20mil pitch QFP 100's and 2 25mil QFP128) that gives us LOTS of lead bridging on the 20 mil parts. There is typically very poor wetting on these parts also, and some joints just flat aren't
Electronics Forum | Mon Dec 13 05:43:27 EST 1999 | Wolfgang Busko
Hi Steve, 20 mil pitch shouldn�t be that problem nowadays. In your case bridging and poor wetting seem to go hand in hand. For the poor wetting try to eliminate it by using different paste (higher activated) and work on your profile. Coplanarity also
Electronics Forum | Mon Sep 20 17:26:22 EDT 1999 | Earl Moon
| I've had some trouble pasting a test board for a MicroBGA trial. Most of the paste remains in the stencil apertures. | The stencil is 6 mil thick, laser cut and electo-polished. | The apertures are 12 mil in diameter with 20 mil pitch. | We are usi
Electronics Forum | Tue Aug 17 10:41:13 EDT 1999 | Steve A
Wayne, Sounds like a gasketing problem. When the horizontal apertures are bleeding but not the vertical apertures. Could be poor underside support, HASL miniscus issues, masking or plugging issues, but what many people do not account for is that t
Electronics Forum | Wed Feb 25 02:33:52 EST 1998 | Scott McKee
| | Stencil Opening | | Looking for spec or any info to specify stencil opening for TSOP48 20mil that will consider also thickens and direction of printing, if applicable | Ron, | Use a six mil foil thickness for your stencil. Go one to one with yo
Electronics Forum | Thu Apr 26 20:18:45 EDT 2007 | hegemon
For what it is worth, we are purchasing a dispensing system including a Robotic Arm, Positive Displacement Valve (as opposed to volumetric displacement) and Controller. We have purchased this unit for doing lead free 20 mil dots at 30 mil pitch in s
Electronics Forum | Wed Jul 09 14:47:39 EDT 2014 | deanm
I'm looking for a typical SMT placement defect rate from others in the field so I can judge whether or not we are in an acceptable range. If I give you a board with 200 components (0603, 0805, SOICs, 20mil MSOPs, tantalums, DPAKs and a few 20mil fin
