Electronics Forum | Thu Mar 18 11:07:45 EDT 2010 | mun4o
hi, lately I have problem with smd leds.After reflow 2-4% of leds are broken.I think , that reason is bad storage of components, because in our stock the tape with leds have not Moisture Barrier Bags.My question is ,how you storage components, which
Electronics Forum | Thu Mar 18 14:33:46 EDT 2010 | jdumont
Is your peak reflow temp exceeding the LED spec? We store our SMT LED reels on the rack with the rest of the discreets and have never seen this issue...
Electronics Forum | Fri Mar 19 09:22:32 EDT 2010 | mun4o
Hi, most of them are MSL 3.There are MSL 4 and 2a.Most of defective LEDs are 3528 footprint.The thermoprofile is Ok??
Electronics Forum | Thu Mar 18 11:42:00 EDT 2010 | cellis
I would recommend doing a google search on smt dry box. There are several supplies of them. We supply them also from http://www.manncorp.com Thanks, Chris
Electronics Forum | Fri Mar 19 07:18:14 EDT 2010 | grahamcooper22
Hi, do you know if your LEDs are moisture sensitive ? And if so what MSL level ? Surprisingly it seems that not all are, but some seem really sensitive. I imagine the differences are down to the plastics used and the LED manufacturing processes. I a
Electronics Forum | Mon Mar 22 10:24:14 EDT 2010 | mun4o
Hi , I think that our problem is humidity, because when I use leds from new tape ( pack in MBB ) no any defects.After that, we put opened tape in our store.After 2-3 weeks I use the same tape with leds, and we have 2-3% defective leds.I make this tes
Electronics Forum | Fri Mar 19 13:18:03 EDT 2010 | deanm
Regarding your question about buying equipment to vacuum seal the MBBs, according to the IPC/JEDEC standard, "Full air evacuation is not needed or recommended; light air evacuation will reduce the packaging bulk and enhance carton packing. Excessive
Electronics Forum | Tue Mar 23 03:42:51 EDT 2010 | grahamcooper22
Hi, It is very important to follow IPC JEDEC 33 specification for storage and handing of all MSDs. In many instances defects caused by excess moisture in packages is not immediately evident (pcbs may pass final test) but when pcb has been in the fiel
Electronics Forum | Mon Mar 22 07:40:01 EDT 2010 | emanuel
Are you absolutely sure the problem is with the humidity? We had a problem with 3528 size leds, damaged by the pick and place nozzle because a 0.2mm mistake in the height measurement. Also, we found that several suppliers are using fake desiccant ba
Electronics Forum | Thu Mar 18 12:46:20 EDT 2010 | deanm
The standard J-STD-033B.1 addresses how to store moisture sensitive components. A dry box is a good, convenient way to store MSDs, but there are other methods to consider which are outlined in the standard. Are you sure that the problems are caused
