120.000 LEDs - logistic nightmare - Page 1
Forum section: electronics / projects

author: Milentije
author_rank: Contributor
timestamp: November 04, 2019, 08:24:06 pm
content: Hello to you all!I have a project on horizon for which I will need ~120000 LEDs. A lot of custom dimensions 7 digit, 7 segment displays for outdoor use.I have very good experience with CreeC566(D) seriesof diodes (high brightness, decent viewing angle, acceptable price). Now I am looking for red ones. 120000 of them. When I combine stocks from mouser, digikey and farnell I don't get even close to needed amount.Do you have recommendations for cheaper LEDs which I can buy in needed quantities? Those from Cree are 0,094€ for 50k QTY. It would be nice if I could find something cheaper, but with similar specs. Ofcourse, something what I can buy in ~120000 Qty.TIA

author: DaJMasta
author_rank: Super Contributor
timestamp: November 04, 2019, 08:33:34 pm
content: Digikey is not a great place for that kind of quantity, and often isn't a great place for prices on optoelectronics. Find a manufacturer with a part you like and talk with them directly if possible.Also, you want to solder 120,000 through hole LEDs?! If you go surface mount, you halve assembly time for the parts even if done by hand, and if you do pick and place in a reflow oven, it's probably less than a tenth of the assembly time. Such a swap may require some redesign of diffusers and housings, but it's probably worth the trouble.

author: Milentije
author_rank: Contributor
timestamp: November 04, 2019, 09:12:22 pm
content: Thank you for your post.You are on point regarding assembly process and time.Any way, I have to contact manufacturers directly because of quantity.Still looking for suggestions from smarter and more experienced guys and girls.

author: tooki
author_rank: Super Contributor
timestamp: November 04, 2019, 10:04:01 pm
content: Would this perhaps be something better made out of something other than discrete LEDs?! I’d think that there’s a very good chance that using LED video wall panels or even LED strips could make more sense.

author: alanambrose
author_rank: Frequent Contributor
timestamp: November 05, 2019, 03:53:16 pm
content: The thing to realise is that nearly all opto products including LEDs, driver chips etc are made in the Far East - mostly China and Taiwan. Very few are made in the Western world. (High end opto stuff is made in Japan, but you don't want those.) So, that's where you need to go. Start with LCSC, Ali, Taobao etc to find some candidate parts #s and then iterate around searching for pricing. Extra bonus points if you find and talk to the actual manufacturer.Alan

author: boffin
author_rank: Unknown
timestamp: November 05, 2019, 04:12:08 pm
content: Quote from: Milentije on November 04, 2019, 08:24:06 pmContact Cree directly. At that sort of volume (and use case), there are minor colour and intensity variations, which from looking at the datasheet you'll likely want to specify

author: Syntax Error
author_rank: Frequent Contributor
timestamp: November 05, 2019, 05:53:32 pm
content: 120,000 multiplied by how many mA? That's 2 to 3KW so you'll need to budget for some robust power supplies. From the PDF, do you really want 240,000 through hole solder connections? Have you considered SMD packages? 1206 or 0805 sized LEDs will be just as bright as regular LED's, but cheaper to source and fabricate. And what are you going to fabricate them onto, PCBs or bus-bars? And how serviceable is this concept? What happens when you need to replace defective LEDs?For this quantity you might like to reach out to Kingbright (EU-German Office)https://kingbright-europe.de/products/But do you really need this many LEDs? Can the same brightness be obtained from fewer parts, such as Superflux Piranha LEDs or even white COB LEDs used in flood lights?As @tooki said, why not just use ready made LED strips? You can get them outdoor IP rated and, when purchased in bulk strips, work out at around $1 a meter.Think cheaper, brighter, easier, better.

author: coromonadalix
author_rank: Super Contributor
timestamp: November 05, 2019, 06:23:45 pm
content: You have some cob leds in rectangles forms, you could create your segments more easily, add some light diffusers and voila ?The cob are very powerful, not as strong as the cree ??

author: Syntax Error
author_rank: Frequent Contributor
timestamp: November 05, 2019, 09:45:58 pm
content: @Milentije I just had a thought, there is an alternative and that's electroluminescent sheet.It's EL wire in a glowing sheet. Used in applications from product stands to aircraft evacuation lighting, you can assemble the sheets into custom shapes. Colors are either native or filtered white light. This 'flat' light might be a better match to your concept? It's not a cheap technology, about 350 Euro a square meter, but how much would mounting thousands of LEDs cost? Just glancing at the specs for the inverters, the power consumption might be lower/greener too.This supplier is located in the UK:https://elpanelandtape.co.uk/el-panel/

author: Siwastaja
author_rank: Super Contributor
timestamp: November 06, 2019, 06:05:26 am
content: Assuming you are in Europe, one additional supplier would be Wurth Elektronic. AFAIK they don't have their own LED fabs, but do have their own brands of likely Chinese LEDs with quality control, and will happily deal with you directly.Yes, definitely go to SMD. Design a module, which is one PCB and can be cascaded. Automated SMD PCB assembly in China is freaking cheap and easily available nowadays. pcbshopper.com also lists assembly houses.With your massive installation, I can see it's easily hundreds of modules, driving unit cost down. I'm sure the cost of SMD ledsandfull SMD assembly will be less than the through hole LEDs alone, even without accounting for the work.The only thing you need to do then, is design and order the PCBs, assembled, then assemble the modules together.

author: Poe
author_rank: Frequent Contributor
timestamp: November 06, 2019, 08:35:32 pm
content: Just some food for thought...We recently stopped producing a product that had 344 LEDs. They were the neopixel type that fed serial data from one to the other. It only took one pixel for the entire string to fail.TheLED manufacturersaid their infant mortality rate was less than 1 out of 1000. We found that one assembly out of five (1 LED out of 1720 LEDs) would fail during test due to a bad LED. The 30-day return rate was one assembly out of four! The 60-day rate was one out of twenty.A different customer design uses 12k discrete LEDs. The claimed LED failure rate was better (1 out of 10k), but the customer would only tolerate two dead pixels per panel. Luckily the failure rate was much better (~1 out of 40k). Unfortunately, this still equated to extremely high rework after test and very high return rates.

author: james_s
author_rank: Super Contributor
timestamp: November 06, 2019, 09:15:14 pm
content: Quote from: Syntax Error on November 05, 2019, 09:45:58 pmEL strip is nowhere near as bright as LEDs and the lifetime is quite limited, stuff I've had with EL backlights deteriorated after a few thousand hours.

author: Apollyon25_
author_rank: Regular Contributor
timestamp: November 06, 2019, 10:52:33 pm
content: Many years ago I was involved with a company making LED video walls.In just a 200mm square module, we had 432 PTH discrete R, G and B LEDs mounted on one side of the board, and the ~1500 SMT drive electronics parts mounted on the other.Our first MP order was 2.5 million pieces of each colour so we talked to Nichia directly and got very good pricing. We used a local CM to assemble the PCBA's and they used glued SMT driver components and a wave soldering process.As noted above you will probably need to specify wavelength and intensity bins for the LEDs. Because we needed to meet D65 white standard at the time, we had to individually measure and correct for brightness and colour shift, dynamically.In another company using IR LEDs we used Osram LEDs and also had these binned. We used various mounting techniques from standard SMT on PCB/FPC, to COB and wire bonding to custom lead-frames.Feel free to PM if you have any more specific questions.

author: mengfei
author_rank: Regular Contributor
timestamp: November 07, 2019, 02:41:06 am
content: if china is an option they'll be glad to ship that you

author: poorchava
author_rank: Super Contributor
timestamp: November 07, 2019, 06:42:04 am
content: Quote from: Siwastaja on November 06, 2019, 06:05:26 amAllso, for WE stuff don't look at the prices on retail websites like DK or Mouser. The prices usually are 5x...10x of what they really are directly from WE. It's not some scam by distributors, but "corporate politics" and this is corroborated by WE FAEs to whom we have repeatedly ranted about this on every occasion.

author: rvalente
author_rank: Frequent Contributor
timestamp: November 14, 2019, 11:59:56 am
content: Contact everlight taiwan, they have great products. Used to work for a dist of them years ago.

author: Milentije
author_rank: Contributor
timestamp: November 19, 2019, 03:13:03 pm
content: Thank you all for your replays and discussion.I was "out of life" for the last ~15 days. Now, I can continue with this.