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SMT, SOLDERING TIPS/TRICKS FOR FLEXIBLE PRINTED CIRCUIT BOAR
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SMT, SOLDERING TIPS/TRICKS FOR FLEXIBLE PRINTED CIRCUIT BOAR

by Sajeel on Thu May 03, 2018 12:28 pm

I have been working on a project for last one year and finding a better way to make this project happen without giving it up.

I am using neopixels SK6805_2427 LEDs to make a custom character shape flexible led panel. I had made its production from china in February, 2018. When I received the led panels and I tested, it was working fabulously and flawlessly but after 10 to 15 days, more than half of the leds was not working. This thing was observed in all panels. I had made 10 panels and all have the same issue. I am confuse now and I am feeling as this problem had come from manufacturing.

The approach which was used is this: it is a flexible double sided PCB with thickness of 2mm, copper layer of 1oz, polymide material was used. Led were kept very closed to each other. the consecutive distance between two leds is around 2mm. Reflow method was used for the soldering of leds.

I have also ordered two 8x8 Neo pixel based flexible led panel and also saw the eagle cad files of led panels here on AdaFruit. Its a great pleasure for me to asking my problem here on Adafruit forums and I came with very hope. Please help me in resolving this problem. I will provide my files and other things on request.

Enclosed: SK6805_2427 RGB LED DATASHEET

Thanks in advance!
Attachments
sk6805 2427 Datasheet.pdf
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Sajeel
 
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Re: SMT, SOLDERING TIPS/TRICKS FOR FLEXIBLE PRINTED CIRCUIT

by franklin97355 on Thu May 03, 2018 2:52 pm

I'm not clear on what you are asking. Have you tested the bad pixels to see if the problem lies with the soldering or bad pixels? Pixels are very susceptible to environmental conditions before and during assembly.

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Re: SMT, SOLDERING TIPS/TRICKS FOR FLEXIBLE PRINTED CIRCUIT

by Sajeel on Thu May 03, 2018 3:01 pm

I do not know how to check bad pixels. I had did testing of led panels myself and when I was testing all pixels was working accurately. Moreover, you are saying these leds are temperature susceptible, can you please more elaborate it.

However, the thickness of my led panels is just 2mm, very flexible, and FPC total size is just 6x6 inches. This FPC contains 670 leds. Does the problem is occurring because of high density of components and very thin FPC?

Thanks
Waiting for your reply.

Sajeel
 
Posts: 20
Joined: Thu May 03, 2018 11:56 am

Re: SMT, SOLDERING TIPS/TRICKS FOR FLEXIBLE PRINTED CIRCUIT

by franklin97355 on Thu May 03, 2018 3:18 pm

The problem may be the flexing of the PCB or bad parts or assembly. It's hard to say where the issue lies.

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Posts: 19244
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Location: Lacomb, OR.

Please be positive and constructive with your questions and comments.