Electronics Forum | Wed Mar 04 15:26:07 EST 2009 | clampron
Hi Jorge, Take a bare board and measure over the same pad. We have had similar issues with a higher deposition than the stencil thickness. In some cases, we have found that the top of the pad was higher than the solder mask. Our inspector uses the b
Electronics Forum | Tue Sep 22 10:29:18 EDT 2009 | stepheniii
To how many decimal places? Do you want to have a factor for different screen printer operators? There is no such formula and I doubt there ever will be one with any real accuracy. The stencil house might be able to tell you the total area of the
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 | Fri Jun 25 12:07:00 EDT 1999 | John Thorup
| | hello, | | | | has anyone tried dispensing solder paste in thru holes instead of waving or hand soldering. if so how did it work out for you. | | thanks for the input | | | | wayne | | | | | | | We have tried this mainly on thru hole connect
Electronics Forum | Fri May 21 15:50:41 EDT 1999 | John Thorup
We are running a number of boards with 8-10 25 mil PQFPs on board. Our process is mature with at least 3 years experiance and statistically few opens on the QFPs. Our beloved purchasing department has chased the almighty $ and changed FAB vendors
Electronics Forum | Mon Apr 12 15:52:12 EDT 2004 | wgaffubar
I am using Indium 92J type 4 solder paste due to a BGA site with .008" pads and stencil opening of .009" square and .005" stencil thickness. When I try the type 3 we get insuffecient print. The aspect ratio tells me that I should be using a type 4. T
Electronics Forum | Tue Jan 16 09:23:26 EST 2001 | P.Gerits
Hello, Standard way to calculate stencil design can be done as follows: A normal ratio of aperture width/stencil thickness = 1.5 for pitches below 650u A normal ratio of stencil aperture width against pad width = 0.8-0.9 (or stencil aperture 10%-20
Electronics Forum | Wed Feb 09 21:41:49 EST 2005 | Grant
Hi, We have been running the same stencils for about a year, 5 thou thick, 1-mm pitch BGA's and every-things been ok, but then suddenly over the last week, 2 different products have had paste release issues with the BGA. It's odd because nothings c
Electronics Forum | Fri Dec 01 12:02:15 EST 2000 | blnorman
I have over 10 years experience in aerospace materials, part of which was involved with vacuum casting inert propellant formulations. These propellants are in the range of 80 - 90% solids loaded with viscosities of 15 kP. I'm not sure where I could
Electronics Forum | Wed Apr 10 13:20:36 EDT 2002 | barryg
I am curious how you measure your printed paste thickness. We are considering doing the same. As it is now we assure we have squeegee pressure and speed controlled, have not actually measure the printed paste thickness.
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