Electronics Forum | Mon Mar 27 08:28:48 EST 2000 | Mark Alder
Dear Robert The reason for the bridging problem you are experiencing on your BGA's is due because of too much solder. The PCB pads need to be at least 15% larger than the sphere size of the BGA balls. If you are not using C4 (63/37) BGA spheres and
Electronics Forum | Fri Apr 20 11:05:23 EDT 2001 | gcs
Just a bullet! My results are, .005" stencil thickness should measure between .0055" - .006" if your pressure is correct, metal blades and snap-off is set up correctly. Do you have aperture reductions at the QFP locations "typicial industry standard
Electronics Forum | Wed Dec 15 10:47:57 EST 1999 | Christopher Lampron
I agree with Wolfgang. We are currently reducing appertures by approx. 10% even on the chip components. This still gives us an adequate fillet volume and very greatly reduces the probability of solder balling/beading. We generally refer to the manufa
Electronics Forum | Tue Nov 09 14:21:00 EST 2004 | Dreamsniper
Thanks Russ. When solder paste is applied, you can't see the pads. Because my aperture reduction is 5% - 10% of the pads. Pads are reduced by almost and up to 20% by the PWB Fab and the paste covers the pad. We cal align and inspect but very hard as
Electronics Forum | Mon Mar 21 12:02:09 EST 2005 | Rob
Hi Colin, Are you using the 1206 package with 4 elements or one of the higher density smaller packages? With the first type you can get them in both Convex or Concave terminations, with most of the solderability problems associated with using the C
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 | Tue Sep 21 04:00:27 EDT 1999 | Wolfgang Busko
| My stencil thickness is 6 mil and we got qfp's with fine pitch. | how many percent should i reduce my stencil aperture using a 6 mil stencil for 0.5 mm pitch and 0.4 mm pitch ? | | thanks | We use 6 mil lasercut stencils with 15% reduction and th
Electronics Forum | Tue Jun 02 15:01:57 EDT 2015 | tombstonesmt
What is the reduction in aperture size for your stencil versus pad? Or are they at 100%?
Electronics Forum | Thu Sep 30 06:47:51 EDT 1999 | park kyung sam
| My stencil thickness is 6 mil and we got qfp's with fine pitch. | how many percent should i reduce my stencil aperture using a 6 mil stencil for 0.5 mm pitch and 0.4 mm pitch ? | | thanks | we have placed 16 mil components for 3 years. why don't
Electronics Forum | Wed Feb 18 14:45:33 EST 2004 | Mauro Pinheiro
I'm looking for a shareware software that I could use for specifying stencils (we are stencil users not manufacturers). I would like to enter some preliminary spec in a software form, such as: the smallest pad geometry on pcb (possibly selected from
