• Author Author: tonyboubady
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TI and Würth Elektronik LED RoadTest+ - Circuit Crafting - 8/10

tonyboubady

Update: I am working on the soldering WE's SMD LEDs with my tricks and ideas. You know what? it really looks cool and works great...but... I don't think I can do the thermal protection with the board I have etched, it seems super hard and as well the amount of LEDs with thermal holes seems almost snap off point of the board, too close and board is getting weak...My design could work with professional PCB with 3 layers. I am going to finish this project up for demonstration purpose only...will update on next post...

 

Hello, here I am again with some update image

 

I have managed to finish the etching process today, successfully... and I am happy about it. I started with printing my circuit design with laser print and I am not using any glossy paper, it was a quite a story that I can't take laser print with glossy paper here, so I have figured out a way to do it with regular A4 paper and some tricks image

 

This is my successful toner transfer to copper clad board...

 

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I had to do some adjustment with permanent marker pen (Sharpie), yeah! that's how we call it here in India.

 

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Now it's time to etch the board with Ferric Chloride - FeCl3 ... and this is the result.

 

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It's not the perfect one but it does the job...

 

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I am happy about the result... even less than half a millimetre space has been etched, really cool... the next process is soldering the SMD LEDs, WOW!!! but I have some IDEA to do it without using hot air gun, soldier paste with oven etc etc... image. I will post my process in next coming days.

  • in reply to tonyboubady

    Hi Antony,

     

    Exactly, you can try to replicate things with what you have access to, such as fill with solder as suggests instead of using copper pegs, and using heatsink compound instead of SIL-PAD, and you will be ok to run at a lower current even if 350mA is not possible. Just usual physics applies, so try to make as much contact as possible using metal (solder or otherwise) or other thermal conductors between the LED and the heatsink, avoid even the tiniest of air gaps, and keep the heatsink large and screwed to the PCB.

  • in reply to shabaz

    Cool, that PowerPeg and SIL-PAD things are something new I have learned from you today... but it's all about what I can buy and access to... so I will try my best with what I have...

  • in reply to tomaja

    Hi

    Interesting idea, it may be possible, if it is filled with solder from the underside somehow and then flipped over and sanded/polished flat. There is a product which would have been suitable too, called the PowerPeg, which is like a copper plug that can be soldered and the attached using a screw to a heatsink. But that needs some practise too, so basically Antony may need to experiment.

    Once it is flat, there are also other interesting products, like very thin sheet material (e.g. SIL-PAD) which can take up small imperfections, but it would be pricey on a large area maybe, so perhaps usual heatsink compound is the way to go.

  • in reply to dougw

    Nice resources, thank you...Yes, I have to learn a lot...I have doubts about the maximum current flow of my design too, my copper clad thickness is too thin and I have gradual 1.016 mm trace width, But anyhow I will proceed with this image ...and yes, I will take your advice and test my LEDs as you said...