Building a UV PCB exposure box?

Hello,

Ideas please?

A small professional UV box with two 8W tubes will cost about £100, and is, professionally made and neat and tidy. I'm wondering if for sake of ease it would be easier to just go out and buy one?

I've seen the UV "fly killer," tubes on eBay for say £10, which are mentioned in a few of the tutorials online. Ballasts I have at home somewhere. Would need a neat little case, cut glass, switches, bits bobs, and time.

This is all purely for making the odd PCB so nothing commercial. There's also those little UV nail boxes for curing the plastic, they're only about £20 although I wonder about even coverage with those, and if indeed it is the right type of UV?

Circular tubes? U-shaped tubes? Straight tubes? Little 9W dual parallel tubes?

I'm just wondering in the end if it would be easier to just buy one, although that's not really in keeping with the spirit of diy.

Many thanks for any input, I'm just looking for ideas and opinons really. I'd also be half tempted to put in regular tubes too so that it can be used as a light box.

Friendly regards,

Alison

ps. There's this one at Rapid for £110 in a little kit;

Reply to
Aly
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Greetings,

Just an alternative, but you said inputs are welcome :-)

You could print the pcb-layout on a laser printer using this "glossy photo paper" eg "EPSON Photo Quality Glossy Paper type: SO41126".

Next you take a normal _CLEAN_ pcb - not the photo sensitive type - put the paper on it and then simply ironing it on will transfer the layout to the pcb.

Etchy - Etchy - Etchy and you have your pcb. As long as you keep the tracks / spacings > 25 mils you should be ok.

It is cheaper than buying the above mentioned kit but produces it bit more coarse pcbs.

One more alternative is

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They produce a Euro-card for you for $ 56 including P&P.

Chees RaceMouse

Reply to
RaceMouse

"Aly" schreef in bericht news: snipped-for-privacy@bt.com...

The DIY spirit found a real cheap method some years ago. Use an obsolete face tanner and an old scanner. An example can be found on

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Although the text is Dutch, the pictures tell the story. I build one this way. Bought scanner and tanner for less then $15,-- on a flee market. The only extras were some pieces of scrapwood, some wire, two screws and piece of hot melt glue. Works like a charm. Two minutes exposure is enough to get perfect PCBs.

You only must make sure that your positives are pitchblack. My printer, although perfect in normal printing, does not make the artwork black enough. I have to stack two sheets to block the UV.

petrus bitbyter

Reply to
petrus bitbyter

You need _quartz_ glass to pass all UV. Apart from this issue, all the mechanical needs are satisfied by taking an old scanner and removing the innards; put the UV tubes and reflector inside where the scan mechanism used to go, and put your PCB on the glass, then close the lid.

Not advisable. If you're building a UV box, you should interlock it so that the tubes cannot come on while the lid is open. There are fun ways of going blind, and dumb ways... stick to the fun ways.

Reply to
larwe

Fly killer tubes are the correct type, but you should be able to get them cheaper than £10 e.g.

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Microwave oven timers are perfect for UV exposure units, especially the ones that go 'ping'

Reply to
Mike Harrison

Not for PCB exposure you don't. Normal glass is fine,

The type of UV tube used for PCB exposure are not particularly hazardous ( unlike the germicidal ones used in UV erasers).

Reply to
Mike Harrison

unlike the germicidal

What wavelength is required? I assumed they were the same.

Reply to
larwe

_Quartz_ glass? I was told so very often. But the glas of scanner is apparently good enough.

Face tanners have no lid. So the need for an interlock will not be that strong. Nevertheless you should not look into the light. If you want to tan your face with it, you need to keep your eyes closed. The light can do serious damage to your eyes.

petrus bitbyter

Reply to
petrus bitbyter

Are scanner glasses usually quartz glass? I have an old scanner here now....

Reply to
Coyoteboy

( unlike the germicidal

There's some germicidal ones on eBay at the moment for any budding EPROM eraser builders.

I'm following this thread with interest :-) I think I'm going to buy one of the ready made boxes. Flea/car boot sales round here have been taken over by commercial companies and health and safety. :-( We're in the UK afterall where the kids aren't even allowed to play football anymore. Frankly I'm amazed they let people handle PCB chemicals even, heaven forbid, they might burn a hole in their trousers.

Here's the eBay link (it may be CR/LF wrapped);

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Reply to
Aly

Thank you to those who are replying. I'm following with interest.

At the moment I'm swaying towards the £100 for sake of ease. Oh, printer, photo inkjet, transparances, Brother DCP-340CW apparently 1200x6000dpi... we'll see about that.

:-) Aly

Aly :-)

Reply to
Aly

is,

it

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I built one using two UV tubes in standard 12" fluorescent fittings, with a box made from MDF and a sheet of glass. It cost me about 20 GBP.

Leon

Reply to
Leon

You don't need quartz, ordinary window glass is transparent to the long-wave UV used for PCB exposure. The light isn't particularly hazardous.

Leon

Reply to
Leon

er,

I use an HP 5940 printer with JetStar premium film, results are excellent.

Leon

Reply to
Leon

I don't use the photo method much anymore, but for many years I did it wifh a UV tanning floodlamp in one of those clamp-on utility lights with a spun aluminum reflector. I'd lay the PCB on a piece of plywood on the floor, with the artwork taped over it and a sheet of ordinary window glass on top to make sure everything was flat. The tanning light was clamped to the back of a chair so it was 2-3 feet from the work, and pointing straight down at the center of the board.

True, that plain glass probably blocked some UV, but so what? The tanning flood puts out a ton of it, and you don't really want a super-short exposure here. Several minutes is fine, since it gives you some room to adjust exposure times.

Best regards,

Bob Masta D A Q A R T A Data AcQuisition And Real-Time Analysis

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Scope, Spectrum, Spectrogram, Signal Generator Science with your sound card!

Reply to
Bob Masta

It depends on the UV wavelength required for this application, I assumed it was rather short-wave. Below 170nm or so quartz glass is really necessary. Germicidal lamps have a quartz envelope.

Reply to
larwe

unlike the germicidal

I think germicidal ones are something like 254nm

There are 3 types of commonly available UV fluorescent - easily distinguishged by their appearance : Clear glass : germicidal/eprom eraser. Dangerous. Black/dark violet : theatrical/disco - not very good for PCBs White : fly killer/PCB UV exposure

Reply to
Mike Harrison

What nM are we talking about for photoresist exposure?

I'm looking at UV LEDs on eBay at the moment. 150mcd, about 400nM.

Search for inside the brackets. ( UV "LEDs" ) to weed out the other stuff.

Reply to
Aly

Not sure they have the intensity needed for etching, youd probably need hundreds of them lol. That said they're fairly cheap.

Reply to
Coyoteboy

UV LEDs can work, Elektor mag. had a design a few months ago.

Leon

Reply to
Leon

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