Electronics Forum | Sat Jan 25 20:17:40 EST 2003 | ramanandkini
We are soldering a 8 pin TTL chip on to a CEM1 board that has a hot air level soldering. We use no clean soler paste for the reflow process. Now the customer wants us to clean since he is afraid of flux attracting the dust. We have some SMT LEDs that
Electronics Forum | Mon Mar 30 03:10:44 EST 1998 | Patrick Ng
Hi, We have encountered de-wetting issues with gold plated components( SMT LEDs ). The problem comes and go and we yet to locate the root cause ( process, component or solder paste etc ). The rest of the components on the boards are not having this
Electronics Forum | Wed Jul 09 11:58:03 EDT 2003 | sam
When we try another test by using less solder paste, we found under the microscope that the solder was actually stick on the LED gold surface, but not having good wetting. By this finding, we can basically conclude that it was poor solderability caus
Electronics Forum | Wed Nov 04 10:31:25 EST 2009 | vetteboy86
I'm not familiar with a puff off setting. I have tried some different things including release delay to shut the vacuum off before the nozzle lifts in the upward direction. I tried to minimally overstroke the part hoping the paste tension would over
Electronics Forum | Wed Sep 01 08:25:31 EDT 2010 | sachu_70
Tombstoning is a result of imbalanced force experiences by the device during reflow due to unequal behavious of the solder paste across all sides of the device. Could be due to many factors a few of this are: (1) Unequal solder mass distribution, (2)
Electronics Forum | Tue Nov 28 14:27:05 EST 2017 | emeto
Without the details I will tell you that you have too much paste. PCB Pad is probably way bigger than the contact lead surface of the part, you overprint, and in the oven this solder have nowhere to go and tilts your part. Check datasheet.Cutting sma
Electronics Forum | Fri May 13 22:24:47 EDT 2022 | glasscake
Try adding blow after mount before head up if your machine lets you. Make sure your placing the part into the solder paste as that will add some holding force as well. If your tips are spring loaded you can do some 0.5mm additional mounting height.
Electronics Forum | Wed Sep 26 11:17:38 EDT 2012 | garym4569
We have been having a solder paste reflow issue which results in the solder not wetting to the LED lead. The solder appears to create "puddles" on the pcb pad. I have attached AOI image for review. We have had the pads analyzed for contamination, w
Electronics Forum | Thu Mar 16 19:12:22 EDT 2017 | pzappella
Hi Rob, Thanks for the LED paper. I like the void area equations but I am puzzled, the paper did not say if the solder was a solder paste that would generate a lot of voids, or a fluxless preform or sinter material. The measured voiding level
Electronics Forum | Mon May 06 11:45:32 EDT 2019 | slthomas
There are quite a few papers out there on the subject. Just enter "SMT void reduction" into google or other search engine and take your pick. That said, slow ramp rates and paste volume reduction are a good place to start. Although I haven't tried i
