Electronics Forum | Mon Nov 13 14:58:56 EST 2017 | davef
Determine the origin of the solder * Sloppy paste printing technique * Lax stencil underside cleaning practices * Sloppy misprint cleaning practices * Poor part placement practices creating solder balls * Poor material control allowing solder p
Electronics Forum | Thu Mar 22 20:56:50 EDT 2018 | jacobidiego
Hi experts, I have some multiple and randomly missing components after reflow. PADs are seen in AOI as if the component was never there. I have seen no evidence of the chipmounters missing any components at all while populating the board. We don't ha
Electronics Forum | Fri Aug 20 10:44:40 EDT 1999 | k.t
| | Is there process by which one can do a double sided reflow (SMT on both sides) in one pass through the oven? | | | Probably not. I have heard people talk of it but never see it done and I wouldn't recommend it. | | Good luck | | Yes, it is d
Electronics Forum | Thu May 05 08:14:45 EDT 2011 | kahrpr
Where black pad exists, it is not a common problem. When I read it is totally random I doubt that. You have defiantly something going on that is unique with the process. It is either your board manufacturer or your solder paste or your profile. It c
Electronics Forum | Sun Mar 25 08:45:00 EDT 2018 | jacobidiego
Normally some random components of size 0604 or below and may be due to a thermal mass being close like a transformer or AC electrolytic caps. We tried changing fan speed, but this will change the thermal profile and avoid the thermal mass from bein
Electronics Forum | Fri Jun 03 04:16:27 EDT 2005 | Bryan She
Background: We use a thermal boards to setup/profiling the reflow oven for pilot run.and then daily verify the reflow profile with this thermal board.Now we phased into LF production,and the LF thermal board can only withstand 25~30 times reflow excu
Electronics Forum | Mon Nov 06 09:38:55 EST 2000 | Dean Stadem
We have seen this problem several times. It always goes back to pad solderability, very seldom does it have anything to do with ball size. If there is no evidence of wetting on that pad, but all of the other pads did solder, you need to ask yourself
Electronics Forum | Sun Dec 05 22:43:27 EST 1999 | dreamsniper
Charley, Though my reply is quite late, it might be a good info for you and i hope that this info could help or could provide you some views. Some companies practice at least 1 board gap, which means the length of the pcb you are currently loading,
Electronics Forum | Wed May 04 19:09:52 EDT 2005 | russ
Can you not just check the part when it is on line and being loaded into the machine? You should only need to check this once. Verify your setup to the bom and not your assembled boards to the BOM. Correct setup and program = correct boards. More
Electronics Forum | Thu Aug 13 14:10:01 EDT 2015 | markhoch
Hi Sam, I have a feeling that what you're trying to communicate is that your DPAK's are skewing off the pad during reflow. This is caused by a thermal "mismatch" where the solder paste on one side of the DPAK becomes molten before the other, then th
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