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 | 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 12:31:16 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
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 | Thu Aug 20 13:01:40 EDT 2009 | bman
When I've seen white strands in the solder on SMT boards, it's been fibers from stencil wipes that stuck to the stencil, then transfered to the board when it was printed. I'm not sure why this would only happen with fine pitch components though.
Electronics Forum | Thu Aug 13 16:46:13 EDT 2009 | snsmt
Hello Everyone, I have noticed that everytime that we have ran a PCB with fine pitch components (or even 0603s), there are little white strands on the leads or on top of the components. It occurs on both lead and lead free solder. We usually soak
Electronics Forum | Fri Aug 14 08:01:25 EDT 2009 | davef
So, in order to understand your issue better, please * Tell us more about your process [eg, process flow, machine setting, measured temperatures, etc] * Tell us more about your materials [eg, board, paste, etc] * Describe the extent of the problem [e
Electronics Forum | Fri Aug 28 05:07:59 EDT 2009 | sachu_70
Do you clean the stencil manually or using the automated under-stencil cleaner on your Printer (recommended)? 1. Ensure that stencil wipes are lint-free and soaked sufficiently with solvent before use. 2. If your printer supports automated cleaning
Electronics Forum | Thu Oct 28 11:50:11 EDT 2010 | phase1
We are having a little trouble with what appears to be a crystalization between our fine pitch parts. The problem appears after a a thourough wash of the pcb when dry. It looks like lead wiskers/haze between the joints.We are using water soluable lea
Electronics Forum | Thu Jun 16 00:24:29 EDT 2005 | mskler
Hi everybody, Can some body tell me that what stencil thicknes is required for the 16mil QFP. I am getting bridging as well as dry at QFP pins. What type of solder 1. Viscocity 2. mesh size 3. flux contents Should be used for this type
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