Electronics Forum | Sat Feb 26 20:44:46 EST 2005 | siverts
Some of the QFN's have/has? (sorry for the grammatics but I live in Sweden) a "ground pad" underneath the center of the body. Some of the manufactories have made a specification of how much solder fillet that needs to be covered on the center pad [f
Electronics Forum | Mon Feb 28 12:01:30 EST 2005 | Bob R.
We use QFNs in automotive products and have done a good bit of experimenting with pad designs, paste patterns, stencil thickness, and thermal via patterns. All of them have an effect on assembly and thermal cycle reliability. There is not a yes or
Electronics Forum | Mon Feb 28 11:31:08 EST 2005 | russ
This sounds a lot like a profile that is killing flux activity prior to wave immersion. What is your topside preheat temp just prior to hitting the wave? What type of preheat do you have, convection or radiant? Are you using a chip/turbulent wave
Electronics Forum | Sun Mar 06 20:08:38 EST 2005 | mrduckmann2000
Davef, You have a good question. If we had perfect design engineers out there that would use the proper component spacing and not put SMT parts between and around thru-hole parts - glue and wave would work perfectly. I have done this with great su
Electronics Forum | Mon Mar 07 10:14:31 EST 2005 | jmedernach
Cellular and PDA architectures employ this technology all the time. You have to be careful with your board supplier as well as with your plugging approach. Leave the via unplugged, I guarantee voids in the solder joint. That leaves us with, "how d
Electronics Forum | Sun Mar 13 23:30:59 EST 2005 | VS
After reflow AOI makes sense because it has the highest coverage of the defects. Problems like tombstone, lifted pins, open solder joints, some shorts and insufficient solder you will not find before oven. I would also not agree with the statement th
Electronics Forum | Mon Mar 21 07:25:12 EST 2005 | cyber_wolf
We have lab sink in our SMT area that we use for washing off stencils and hand tools that are contaminated with solder paste. The sink has a float in it and when the water level reaches a certain point it pumps the main basin out through a filter th
Electronics Forum | Tue Mar 22 06:08:45 EST 2005 | Grant
Hi, We used to manually profile by comparing logged temp numbers and matching the paste profile. But we got a KIC and it's software was so much better we got a good reduction in rework and we have almost no first run faults now. I would recommend on
Electronics Forum | Tue Mar 22 07:39:05 EST 2005 | davef
There is no standard. This is a relative test. If you wish to do tests of this kind, we suggest to pay attention to the following points: * Shear strength of soft solder depends on the deformation speed applied. The faster the material is deformed t
Electronics Forum | Wed Mar 30 20:06:07 EST 2005 | Sue PH
Ken, I run a Triber and have a manual. This machine was bought used and came to this company before I did. It looks like the manual is a copy and someone wrote Treiber 700B-16F on the front page. I don't know if this is the same machine as yours o
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