Electronics Forum | Wed Jan 17 10:14:37 EST 2007 | slthomas
2-3mm would seem close enough to affect the air flow and I was thinking it could be displacing the qfn. However, if you ran a failed board back through reflow and it was functional after that, I'd put my money on insufficient reflow. I suppose it's
Electronics Forum | Fri Jan 19 13:31:14 EST 2007 | lit51
Is the failure just out of tolerance or is it non functioning? For tolerance problem, compare the x-rays of the good and bad units. It will take a very high resolution x-ray to spot the differences. Changes in capacitance values can occur based on
Electronics Forum | Mon Feb 21 08:39:10 EST 2005 | pemnut
There are so many variables to this. It could be paste, pad size, contaminated components-pads, placement speed, component thickness being wrong in the program, dropping parts into the paste instead of placing them, component recognition ploblems. Is
Electronics Forum | Thu Jun 13 03:15:01 EDT 2002 | jkhiew
Hi Jax, After component placement, all melf diodes being checked & found no touching each other. Unfortunately, after reflow those MELFs are shorted.
Electronics Forum | Wed Feb 16 17:38:17 EST 2005 | russ
have you checked the registration of the component prior to reflow? If this is good, why don't you take another P/N (0805)that is okay and place of few of them in the trouble spots and see what happens.
Electronics Forum | Mon Mar 04 13:13:52 EST 2019 | scotceltic
What temperature spec are people using in the industry to make sure an electronic component is SMT reflow compatible ? Ex. I have some parts that I want to possibly process as Pin in Paste but am not sure what temperature ratings the plastic will m
Electronics Forum | Thu Nov 11 19:07:39 EST 1999 | Gary Kemp
We are having a continuing problem with 0603 chip capacitors not centering themselves on the pads during the reflow process, causing an open condition at one end. Does anyone know what can be done to alleviate this? Thanks much. Gary
Electronics Forum | Wed Jun 12 22:35:03 EDT 2002 | jkhiew
We had alot of problem with melf diode short together after reflow soldering. The clearance is about 0.8mm & we used "v" shaped opening . PLease comment !
Electronics Forum | Fri Jan 12 00:59:04 EST 2007 | Guest
Your evaluation results confirms that Real Chunks is right on thermal mass absorption of the shield, that probably brought cold spots during reflow . I agree with his suggesttions as well.
Electronics Forum | Fri Jan 12 02:11:32 EST 2007 | aj
All, I ran a failed board back thru reflow with shields removed and it works fine. I think that tells me something ? Thanks all who contributed to the thread. aj...
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