Electronics Forum | Mon Dec 10 13:26:40 EST 2012 | dyoungquist
We are using our selective solder machine to solder a backplane with sixteen (16) 4x48 pin 0.080" connectors. Our first pass yield is about 85% meaning that 85% of the connectors come out with no bridges. Not quite as fine pitch as your connector a
Electronics Forum | Tue Sep 17 15:47:42 EDT 2002 | stepheno
Where I worked previously we had some boards with a couple 15 mil pitch parts. The first batch we got all had undersized pads. We had lots of bridging. We had less bridging with bigger pads. The ball size in the paste makes a bigger diffence regar
Electronics Forum | Tue Sep 17 15:03:33 EDT 2002 | ccross
I am working with fine pitch components (15-20 mil) and having soldering problems and would appreciate some opinions. 1) How much of an effect does pad size have on bridging? 2) How much of an effect does solder paste grain size have? What is the re
Electronics Forum | Fri Dec 07 13:31:09 EST 2012 | kenkay
We had a similar issue and it was fixed by trimming the connector so there was barely enough lead protrusion through the board to show a discernible lead. We had to get a special plate and small machine to cut the connectors, but we haven’t had a bri
Electronics Forum | Thu Sep 19 11:14:45 EDT 2002 | Jim M.
We had lots of problems with bridging on 15.8mm pitch, QFP17-160 at the start.The board was .032 thick, double sided-six boards to a panel. Here is the problems (not neccessarily in the biggest to little but as i remember them) and solutions that he
Electronics Forum | Wed Sep 18 18:41:17 EDT 2002 | davef
People have made good comments. Additional points are: * Your bridging is probably being caused by one or more of the following: [1] printing too much paste, [2] smearing the paste during placement or subsequent handling, or [3] paste slump during t
Electronics Forum | Wed Sep 18 12:35:56 EDT 2002 | stepheno
Fourth - > back to design of PCB. Are there solder dams of > mask between the pads? If yes, that helps. If > not, pay close attention to stencil aperture > width and be sure that the aperture deposits less > paste by 1-2 mils per pad, centered o
Electronics Forum | Tue Jan 08 09:23:18 EST 2013 | lock_2002
This is a question regarding soldermask between pins of fine pitch devices. The majority of our production designs end up with at least 2-3 mils of copper thickness on the external layers due to blind vias, wrap plating requirements, etc. Our curre
Electronics Forum | Thu Jun 16 08:31:15 EDT 2005 | jh0n!
The most part I have the most difficulty with is a 16mil QFN. We found that reducing stencil thickness to 4mil, and reducing aperatures for the IC by 20%, and setting local fiducials to the IC helped immensely. We used to get 75% or more bridged ou
Electronics Forum | Wed Sep 18 12:31:16 EDT 2002 | dragonslayr
My suggestion is to conduct a Design For Manufacturing (DFM)study on the assembly in question. Pay particular attention to the pad sizes, component lead dimensions and satisfy yourself that those two factors are correct. Given that pads match compone
