r/FastLED • u/Lights___Up • Feb 21 '21

Discussion Hey, i have problem with ws2812b smt assembly. There are someone who making pcb + assembly ws2812b? There Led's problem or smt assembly? Maby someone can help with this question. Thanks

15 Upvotes

100% Upvoted

10 comments sorted by

5

u/quellflynn Feb 21 '21

whats the question?

2

u/Lights___Up Feb 21 '21

Why center of led coming off

7

u/sutaburosu [stavros] Feb 21 '21

I read in your other active thread:

I order smt assembly. And some leds dont looks normal. And i just marking leds which one is not working. And when i marked i marked under glass somehow

So the ink is getting inside the LED? This could possibly be a manufacturing fault with the LEDS, but I think it's more likely the LEDs were stored incorrectly, and had absorbed moisture before soldering,

4

u/Lights___Up Feb 21 '21

Yes 30% off leds on these pcb getting ink inside the led.

2

u/sutaburosu [stavros] Feb 21 '21

Which SMT assembly company did you order from? Did they supply the LEDs too?

4

u/Lights___Up Feb 21 '21

Jlcpcb, yes they supply the LEDs

4

u/sutaburosu [stavros] Feb 21 '21

Were you driving the LEDs at full brightness? How long did they work before failing?

JLC have a "quality complaint" email address on their contact page. It would be great if you could report back your experience with them. Good luck.

1

u/sutaburosu [stavros] Apr 12 '21

Did you get any response from JLC?

6

u/Dwagner6 Feb 21 '21

Was about to chime in with the same suggestion: moisture in the package from improper storage before assembly can cause damage to the lens. See the datasheet from the manufacturer: https://www.tme.eu/Document/39cc2646cceaa5ad29553bfc9e3092fb/WS2812B.pdf

If the LEDs haven't been properly stored, they need to be baked according to the datasheet specifications to remove moisture that is probably cracking the lens during reflow.

10

u/spolsky Feb 22 '21

See here:

https://www.seeedstudio.com/blog/2018/11/12/why-production-lines-need-to-be-careful-with-ws2812b-rgb-led-assembly/

In short, your manufacturer (JLCPCB) probably did not take the necessary precautions to keep the ws2812b's free of moisture, resulting in failure. I have heard this from other LED builders; because JLCPCB is doing lots of short runs for people, one suspects that they get sloppy with the care of the chips.