16 thoughts on “UV box for PCB exposure

  1. I built my own using a normal flourescent light (while it was in my ceiling), a ladder, a cardboard box, some tape, and a transparency with the circuit on it. It works quite nicely if you don’t accidently move it during exposure.

  2. #4:

    I don’t know if LEDs would be a good idea; not only would you need *hundreds* of them, but you may run into the problem where since the beams of the LEDs are very focused (compared to the diffuse nature of the flourescent tube) that you get strange polka dot type effects.

    Also; Flourescent lights are way more efficient than LEDs — see http://www.otherpower.com/otherpower_lighting.html

  3. #4:

    I don’t know if LEDs would be a good idea; not only would you need *hundreds* of them, but you may run into the problem where since the beams of the LEDs are very focused (compared to the diffuse nature of the flourescent tube) that you get strange polka dot type effects.

    Also; Flourescent lights are way more efficient than LEDs — see http://www.otherpower.com/otherpower_lighting.html

  4. You do not really need this if you live in a “sunny” area on this planet. During Summer in Taiwan, you need at least 15 and better not more than 45 seconds exposure – thanks to our sun. OK, you can not work at night and when it is raining, but in most cases you should be fine. I did this with layouts down to 0.2mm track width…

  5. Does this thing really need a microcontroller? What happened to a 555 timer & variable resistor?

    I built my PCB exposure unit using UV LEDs, because they were cheaper than fluorescent tubes. It pretty much works but the diffusion/polka dot issue is a hassle. I use a couple of layers of tracing paper spaced at different heights away from the LEDs in order to spread it out. I do think fluorescent tubes would probably be easier to work with.

  6. We wouldn’t do that big, but we already had a bunch of UV lamps – I think it’s a good idea to use them this way, isn’t it? Of cource it is enough to use one lamp or even sunshine – it is just matter of time.

  7. Bah, if you buy the right presensitized PCBs, you don’t even need a special UV exposure lamp. Look here:

    http://www.web-tronics.com/printed-circuit-board-supplies-positive-photo-resist-pre-sensitized-pcbs.html

    These photo resist pre-sensitized boards are so highly sensitive to UV that you can expose them to regular fluorescent bulbs and have them fully developed in 8 minutes or so. Plus, they are really cheap too!

    You can buy a regular fluorescent lamp fixture and bulbs for less than probably $20 down at Wal-Mart.

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