Electronics Forum | Tue Sep 10 07:24:13 EDT 2002 | John
I need teoretical info for theme "Matted surface vs solder ball". Is it right that some solder pastes decrease solder balling but give matted surface after reflow? That diference between these pastes and others? Are the matted surface worse solder b
Electronics Forum | Thu Jul 29 21:11:13 EDT 2004 | davef
Could be lots of things. With limited information about temperatures, solder alloy, and cleaning; we'll swing for the fence that you got these solder connections very hot. So hot that Pb oxide is dominating the solder joint surface instead of the
Electronics Forum | Wed Jul 28 17:34:27 EDT 2004 | Steve Stach
Hi Ralf, This discoloration may be re-oxidation. Fluxes are supposed to do three things (1) remove oxide, (2) promote wetting, and (3) protect surface from reoxidation. The solder paste possibly is not protecting from reoxidation. Best Regards, St
Electronics Forum | Wed Jan 16 20:06:09 EST 2002 | davef
No, not as such. Consider: * Using the IPC calculator [free at http://www.ipc.org]. It allows you to consider / assess the amount of solder when designing pads. * Reviewing IPC-7525 - Stencil Design Guidelines. It gives general aperture guidelines.
Electronics Forum | Wed Jan 16 15:22:29 EST 2002 | Terry Burnette
In his book titled "Manufacturing Techniques for Surface Mount Assemblies" author R.J. Klein Wassink describes the relationship between solder land dimensions, component lead coplanarity, board warpage, solder volumes, and solder paste flux wetting b
Electronics Forum | Wed Jun 14 08:08:56 EDT 2000 | Wolfgang Busko
Hi ji tae, we had a similar problem with QFPs 0,5 pitch processed by one subcontractor. The symptoms we noticed were: - the solderjointshape and wetting looked normal - the surface had a dull gray appearance - by pushing a lead sideways with a tweez
Electronics Forum | Thu Jun 27 17:32:35 EDT 2013 | tpost
We recently had a question come up regarding the amount of solder on a flat underside termination ( we referenced Flat Lug Lead in IPC 610). Judging by the photo you can see on the Left is a target solder joint, but on the right is one which had rewo
Electronics Forum | Mon Jul 01 12:37:38 EDT 2013 | tpost
I do have access to an X-ray but it is only 2-D and it just appears as a black solder joint, not to impressive.. The main question though if it is a reowked solder joint does it still need to show wetting on the lead or can it be covered with solder
Electronics Forum | Fri Apr 18 11:38:50 EDT 2008 | sueph
I have a small board with some chips and 2 connectors (1 large and 1 small) with gull wing leads. The large connector has some "disturbed" solder joints per my QA people. These joints are toward the ends of the connector, not toward the middle. Th
Electronics Forum | Mon Jul 01 13:19:55 EDT 2013 | emeto
I always look for a toe fillet if the design allows you to. Many times the pad design is close or exactly the size of the leads which makes people to touch it up right away. I told them hundred times not to but...Luckily I have 3D x-ray and I can tel
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