I recently created a board with a bunch of SK6812MINIs on it but I can’t help but think that the footprint is wrong for reflow. After reflowing my board in my oven, almost all of the LEDs shifted randomly. The SK6812 has a funny asymmetric pad pattern on the bottom. I also think the extra long pads are causing issues when I reflow the board. I suppose it also might be due to the fact I used Chipquik low-temperature solder, but all of the other components came through just fine. This is a pain since I had to use a rework station to fix 192 LEDs. Fortunately, the LEDs seem to be immune to cooking with the low-temperature solder.
So, your suggestion is to remove it or perhaps mark it ‘hand solder’ based on your experience?
Sadly yes. I mostly fault the poor documentation for this device. The footprint documentation is pretty much useless with almost no dimensions given. I’ve already designed a next generation bboard where I’m switching to the WS2813B-Mini which is much better documented in addition to being much more robust against failure.
I also tried hand soldering with my iron when not all of the pins made a connection but I found that didn’t seem to work either. Perhaps it’s my soldering skills or the fact I used Chipquik bismuth solder paste so as to not overheat the LEDs. In the end, I used my rework station to reflow the solder and tweezers with the board powered on. The DOUT seems to be the hardest pin to get a good connection with. What was fun was each flex board has 96 LEDs. I don’t fault whoever provided the footprint.
Perhaps if the pads did not stick out so far it might work better. I may experiment with a test board to see if I can improve this. after my current projects settle down.
I also see that SnapEDA.com has a footprint for this device which looks like it may work better. I have found many useful footprints here as well as 3-D models (some of which I’ve paid for). Note that all SNAPEDA footprints, symbols and models are under a creative commons license.
This is what I made and used successfully (with reflow) a couple of years ago, vs what’s in the library (top):
A corresponding 3D model is in my 3D library:
Feel free to add it to the KiCad libs.
I’ve used some of the SK9822 with reasonably good success. I did use lead solder. The plastic material of the body is terrible. It melts easily, so had soldering is NOT a good idea. If you put the boards in an over, don’t burn them! Watch the time/temp profile and get them out quickly once the solder melts.
That’s why I used the bismuth solder. I set my rework station to 150C and the LEDs don’t seem to care. I have a hell of a time lining up all four connections though, especially the DOUT. I found it works best if they’re a little bit skewed.
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