DIY UV exposure.

[lexter]

Hi!
I've got a wild idea of creating an UV pcb exposure machine. So, I have a number of questions:
1. Is it safe? (some say that UV light is seriously dangerous ... any real facts?)
2. Is there any info on the net available about driving UV lamps?

The links to the information would be more than enough ... made a "google research" on the net, didn't find anything useful ...

PS!

The reason for that project is the cost of the actual device ... in .fi it's around 500EUR for one-sided, way to much for my current hobby found ...

Thanx in advance ...

 

[kchriste]

I used an old tanning lamp once to erase 27C series eproms. It took a little long (3hrs) but it did work.

 

[Sceadwian]

UV lamps are just fluorescent tubes, so just choose a ballast that meats the drive needs of the specific tube you get. UV can be very dangerous, mostly to eyesight, but obviously tanning too much causes skin cancer so it's not so good for the skin either. Avoid directly looking at the tubes and shielding it as much as possible. Skin contact really requires a lot of power and time which you don't need to use for PCB exposure. You should be able to find UV safety glasses on the net pretty easily, but if you just build an enclosed cabinet there's no need to worry, short duration exposure isn't going to harm anything.

 

[monkeybiter]

you can buy cheap small uv tubes or even more expensive mercury vapour bulbs etc from pet supply shops. might have to check wavelength requirements though.

 

[mneary]

Looking at any intense light source is dangerous to your eyesight. Problem with UV (and IR) is that you (and your eyes) don't have the same reaction as with visible light, and you can easily overexpose your eyes without knowing it.

With this in mind, the rest should be common sense: treat it as an intense light source even if it doesn't look like one.

 

[Sceadwian]

Monkey.. UV tubes are mercury vapor bulbs, same thing. The only difference between UV tubes and common fluorescent light tubes is the phosphor coating on the inside of the tube which converts the UV into human visible light. UV tubes should therefore actually be cheaper than common fluorescent tubes because they don't have to pay for the phosphor coating. They're even easier to find nowadays because UV tubes are very popular in water purification products because the light spectra inactivates active biological compounds. (virii bacteria)

 

[lexter]

Well, the tubes are available in my favorite local electronic shop PARTCO. Basically, 1 tube costs smth like 10EUR, compared to the exposure unit price ... Well, found there one unit for ~250EUR, but still ... still ...

What about the cabinet for the bulbs? Is there any material, which would be preferable for it? Or is it just enough to have a wooden box covered with aluminum foil?

Thanx again!

 

[roar]

DIY UV exposure

Hello Lexter.

Get yourself a copy of the Silicon Chip magazine, November 2007 issue, for a great article on making your own UV lightbox with timer. This is an Australian produced periodical distributed nationally - e-mail them at silicon@siliconchip.com.au. for details of your local outlet.

Regards

 

[lexter]

Hello Lexter.

Get yourself a copy of the Silicon Chip magazine, November 2007 issue, for a great article on making your own UV lightbox with timer. This is an Australian produced periodical distributed nationally - e-mail them at silicon@siliconchip.com.au. for details of your local outlet.

Regards

Thanx! I'll try to find it as soon as possible!

 

[mvs sarma]

Check for a modern circuit using UV LEDs in Elektor May2006 magazine. there are definite reports of its GOOD performance and we will save lot of power.

 

[Speakerguy]

Is this just for PCB exposure? We always just set ours on top of a regular shoplight that was upside down and the regular fluorescents exposed it in a few minutes. You could also use Actinic bulbs meant for aquariums (fluorescent bulbs with major peak @ 420nm) or blacklights.

UV bulbs are dangerous. We were running some as a test experiment overnight in a work bay that had a crappy door w/holes on it. We put a cardboard box over it to shield the UV, but left an air gap for ventilaion. Came back the next day and there were tons of dead bugs under the box, including big stuff like moths. Cooked to death over their love of ligh.

 

[House0Fwax]

What about the cabinet for the bulbs?

How about adapting a scanner ?

 

[monkeybiter]

Sceadwian.. i use flourescent uv tubes for my reptiles. also available are uv bulbs that fit into an edison screw fitting [and are much more expensive]. are these just flourescent tubes physically reconfigured. along with ballast/starter etc. into a smaller package?

 

[lexter]

Well, I've heard that UV lamps are really dangerous, that's why actually asking here ...

The thing is that currently, I have a UV box & LPKF "PCB Plotter" (is it the correct word) in university, however going to graduate soon, so, would be nice to have smth available @ home as well. Sometimes, I'm using the pretty common toner transfer method at home, but it is really messy, when it comes to the bigger projects.

As for using the regular fluorescent lamps, is it really working solution? Or am I getting it wrong?

 

[johankj]

Check for a modern circuit using UV LEDs in Elektor May2006 magazine. there are definite reports of its GOOD performance and we will save lot of power.

I've built one of these, with UV-LEDs I bought of Ebay. It works really well. I use about 36 LEDs, and I can do europa cards with it. Exposure time in my unit is about 6-7 minutes. I haven't built a timer for it, I just unplug it. UV LEDs are not safe to look directly at, they will damage your eyes.

Edit: I works great!

 

[Sceadwian]

Depends on the photo resist lexter. Regular flourescent bulbs convert most of the UV to visable light in the phosphor but some still gets through. It is dangerous, but only if you do something silly as said like stare at the bulbs or not shield it and expose your skin to it for long periods of time. The biggest risk is that they don't look that bright because most of the light they're emitting isn't visable, but it will still damage the cells in your eyes just like a bright visable light will, thing is you won't even realize it until you can't see.

 

[mneary]

Well, I've heard that UV lamps are really dangerous,

You must have missed my earlier post. They are dangerous when misused, so don't misuse them.

 

[lexter]

Well, what about the shielding then? e.g. Silicon chip and similar magazines provide an idea of a wooden box. How safe is that? Or, say, wooden box covered with aluminum folio inside?
Basically, now I've got an idea of circuit for the whole thing in my mind, but the only one thing which I have to take care of is safety. h

 

[Nigel Goodwin]

UV is light, light doesn't pass through a wooden box - no problem.

 

[ericgibbs]

Well, what about the shielding then? e.g. Silicon chip and similar magazines provide an idea of a wooden box. How safe is that? Or, say, wooden box covered with aluminum folio inside?
Basically, now I've got an idea of circuit for the whole thing in my mind, but the only one thing which I have to take care of is safety. h

hi,
The aluminium foil lining the inside of the box is acting a simple light reflector in order to give improved light dispersion within the box, its purpose is not screening.

I have never heard of anyone being harmed by the radiation from a simple/low power UV pcb exposure light box.