Devil_H@ck

Hi,

I made a tutorial about how to make PCBs with UV light, I thought it might interest you all.
Here's the URL: http://members.lycos.nl/anthonyvh/index.php?page=pcb

zachtheterrible

That's a good tutorial. I've always thought that you make PCB's a lot simpler. I thought that you buy some copper foil that sticks to the board, then cut it w/ a razor blade. I know it wouldn't be as precise n everything, but it would work. Is there such a thing?

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DigiTan

Very good tutorial! I've made a couple UV circuitboards recently and I was suprised by the level of detail you can get from them. (Enough detail to work with most SMT parts.) I had some trouble with my ink jet transparencies due to blotting, so I took a paper copy of my traces to Office Max and they did an excellent laser transparency for less than $1 (U.S.). It's an excellent way to build a PCB! :wink:

Nigel Goodwin

There used to be, back in the 1970's - presumably it flopped and I've never seen it since - a free sample was given away in Practical Electronics, along with a project that used it.

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Devil_H@ck

Thanks all !

I think you can make boards for just about any SMD part, except maybe BGA's, I don't know what their "pin" spacing is, altough it can't be all that much smaller than TSSOP.

I used to go to a store too at first, but it's more expensive, and I find that the ink on laser printer transparencies gets lose when you accidentally scratch it, which is not the case with inkjet transparencies.

pandaemonium

Good tutor. Heres a few points you might want to try/add.

1. Instead of using tape to secure the two transparencies together, you can put a few drops of water between the two sheets, this insures that the sheets are perfectly mated and it is easier to align the two sheets. I used to use tape but had problems with shadows/blurred lines. I don't know how ink jet ink reacts to water though, I use a laserjet.

2. Make sure there are no burrs on the edge of the cut printed circuit board, file or sand the edges. If there are edges, the transparencies won't mate to the PCB surface properly and may result in shadowed/blurred lines around the edges.

3. UV lamps are not needed, I use a standard florescent lamp with an exposure time of 12 minutes.

4. Sanding to remove the resist is not necessary. A 0000 grade steel wool can be used (careful, some brands have oil in them!) or use a solvent or place the board back in the resist developer. If you wish, the resist does not need to be removed at all, it acts as a flux and can be soldered to directly.

Thanks for the tutor, I was thinking of writing one myself but I never could find the time!

StupidDum

I've tried to make a few pieces of PCB, but all failed. haha.
I dont have a pre-coated board, I had to spray the syntitizer on the board. That is the most troublesome, problematic stage. I gotta do it in dark, thats why I not able to see if the spray is even throughout the surface. After that, I have to wait long hours for it to dry, but I cant tell how long it takes, because I can't see it, I can't touch it.

grrr_arrghh

what do you mean by "standard florescent lamp". Do you mean the sort of lights that you use in kitchens (strip lights)?

Thanks

Tim

Devil_H@ck

It might work without one, but I highly recommend them. The UV reactive stuff on the PCB is, as the name suggests only reactive to UV light. While it might work with standard lamp, UV lamps will be a lot quicker and probably more accurate. Sunlight works to, I did it with sunlight in the beginning, but results aren't really good. It's almost impossible to know the exposure time, because the sun's intensity is different every day/hour.