Electronics Forum | Mon Sep 24 18:00:58 EDT 2001 | jagman
Does anyone know the cause(s) of solder flowing through a via to the other side of board during reflow causing solder bumps on opposite side? Is this mainly a design issue or could it be process related? Any help is appreciated.
Electronics Forum | Mon Sep 24 20:33:34 EDT 2001 | davef
Assuming you're seeing this during wave solder, the via acts like a heat pipe conducting 450�F [or whatever] air to your solder balls. Check the fine SMTnet Archives for similar threads and perspective on the direction to take.
Electronics Forum | Tue Sep 25 12:49:58 EDT 2001 | Hussman
Been there - done that. Makes a mess on that 2nd reflow process- doesn't it!?!?!? This is caused by design. If the open via is located in the land area, it will flow thru the via and cause pumps on the opposite side. You can have your vias filled
Electronics Forum | Tue Sep 25 14:08:59 EDT 2001 | davef
Oooo, the solder on the pad and PGA ball is flowing during reflow down the via to the secondary side? Why didn�t you say so?? ;-) Why would you expect that gravity and capillary action wouldn�t force solder to flow down the solder plated via to the
Electronics Forum | Tue Dec 05 03:39:39 EST 2006 | pavel_murtishev
Good afternoon, Due to problems with power connector soldering I have to overprint paste on pads for this connector. Stencil thickness is 125um and I cannot make it thicker. Area ratio of chip resistor assemblies limits stencil thickness to 125um. R
Electronics Forum | Thu Mar 08 08:03:16 EST 2007 | ck_the_flip
ENig can vary in quality, but I've never seen an ENiG board that's been downright unsolderable. At a CM where I worked, I had to prove a QE wrong. He was flippin' out (*no offense*) about black pad, something commonly seen on ENig boards, so what I
Electronics Forum | Wed Dec 06 16:17:31 EST 2006 | Mario Scalzo, CSMTPE
Normally, we try to limit the over print of the paste to the width of the pad on both sides. If you are using 500um pad, then I wouldn't try over a 1500um aperture. Mario Scalzo, CSMTPE, Dartmouth 6 Sigma Green Belt Technical Support Engineer - Ind
Electronics Forum | Mon Mar 05 16:16:08 EST 2007 | Mark
Hello, We are having issue with one of the customer board. This is 10 layer PCB FR4 with black solder mask. Coating Ni/Au. Soldering leadfree. We are using 7 zones air reflow oven (zones top&bottom). We have bed solder flowing for this boards. T