Electronics Forum | Fri Feb 17 11:01:47 EST 2006 | amol_kane
with lead-free solders, one would expect to find less instances of tombstoning. this is because SAC alloys are not eutectic and melt over a range of temp (usually 217-220 deg C) instead of at a single temperature. therefore the forces due to solder s
Electronics Forum | Fri Mar 03 14:40:22 EST 2006 | amol_kane
i think a more important issue here would be the reduction ratio. as LF solders have a higher surface tension, they do not flow as well as their leaded counterparts. therefore the stencil design may have to be changed (hence a new stencil) if the red
Electronics Forum | Thu Jun 01 16:30:05 EDT 2006 | slthomas
Just wondering if anyone knows this off the top of there head. I might be able to figure out the math based on surface tension (this is 63/37 so the data is out there) but I REALLY do not want to put that kind of effort into this. :/ Editing to clar
Electronics Forum | Tue Jun 06 15:45:18 EDT 2006 | slthomas
Yep. What I'm really looking for is the minimum radius of curvature for 63/37, which is a function of it's surface tension. It's physical properties issue, not an agency issue. I've seen some references that I have interpreted to mean that it's some
Electronics Forum | Thu Jun 08 03:40:32 EDT 2006 | aj
Hi, I use convection reflow and both top & bottom settings are the same. Is the part too heavy to rely on surface tension? there is an equation that can determine this (aswell as real test i.e. part falling off) We have some SIM Card holders on bot
Electronics Forum | Tue Sep 12 22:34:33 EDT 2006 | davef
Bob: Did you know that soldering equipment suppliers make these things that they call 'rework equipment'? This equipment employ these wacky pieces of metal, sized to each particular component, called 'nozzles'. Manufacturing companies use this rewo
Electronics Forum | Wed Sep 13 08:57:34 EDT 2006 | russ
yep, steve is right, it was kind of a joke but I have attached nuts and bolts to QFPs when it was deemed that a lot of components needed to be removed from some assemblies in a quick amount of time. Fit just means that it will fit onto part. thought
Electronics Forum | Fri May 18 10:56:09 EDT 2007 | patrickbruneel
Hi smtnetters, I�m looking for reference material preferably graph�s displaying the viscosity and surface tension vs. temperature for standard Sn63 Pb37 alloy. Plenty of reference material is available on pure metals but can�t find anything on the
Electronics Forum | Mon Aug 13 10:00:18 EDT 2007 | ed_faranda
Might want to check to see if the weight of your part has increased. If it has increased, you may not have enough surface tension to hold the part on the board. I am assuming you already checked that the component isn't getting hit by something in
Electronics Forum | Tue Jan 15 08:50:07 EST 2008 | ck_the_flip
Based on past, actual, hands-on experience, I have found that the PCB mask finish makes a HUGE difference in solder-balling. Glossy has different surface tension and peelback characteristics than matte finish (ie glossy sucks). http://circuitsassem
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