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Discussion Groups | Comp.Arch.Embedded | Building a UV PCB exposure box?

There are 34 messages in this thread.

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Re: Building a UV PCB exposure box? - 2007-04-06 09:54:00

"Aly" <,s...@sliuflky4iuhdf.erl> wrote in message
news:Y...@bt.com...
> Hello,
>
<SNIP>
>

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 :-)



Re: Building a UV PCB exposure box? - Leon - 2007-04-06 09:55:00

On 6 Apr, 11:05, "Aly" <,shfskf...@sliuflky4iuhdf.erl> wrote:
> 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;
>
> <http://www.rapidonline.com/searchresults.aspx?style=0&kw=34-0690>

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




Re: Building a UV PCB exposure box? - Leon - 2007-04-06 09:57:00

On 6 Apr, 12:03, "larwe" <zwsdot...@gmail.com> wrote:
> On Apr 6, 6:05 am, "Aly" <,shfskf...@sliuflky4iuhdf.erl> wrote:
>
> > somewhere.  Would need a neat little case, cut glass, switches, bits bobs,
>
> 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.
>
> > 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.
>
> 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.


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



Re: Building a UV PCB exposure box? - Leon - 2007-04-06 10:00:00

On 6 Apr, 14:54, "Aly" <,shfskf...@sliuflky4iuhdf.erl> wrote:
> "Aly" <,shfskf...@sliuflky4iuhdf.erl> wrote in message
>
> news:Y...@bt.com...
>
> > Hello,
>
> <SNIP>
>
> 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 :-)

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

Leon




Re: Building a UV PCB exposure box? - Bob Masta - 2007-04-06 10:13:00

On Fri, 6 Apr 2007 11:05:04 +0100, "Aly"
<,s...@sliuflky4iuhdf.erl> wrote:

>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.
>

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
           www.daqarta.com
Scope, Spectrum, Spectrogram, Signal Generator
    Science with your sound card!

Re: Building a UV PCB exposure box? - larwe - 2007-04-06 10:31:00

On Apr 6, 9:09 am, "petrus bitbyter"
<pieterkraltlaatdit...@enditookhccnet.nl> wrote:

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

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.


Re: Building a UV PCB exposure box? - Mike Harrison - 2007-04-06 10:36:00

On 6 Apr 2007 05:32:44 -0700, "larwe" <z...@gmail.com> wrote:

>On Apr 6, 8:28 am, Mike Harrison <m...@whitewing.co.uk> wrote:
>
>> The type of UV tube used for PCB exposure are not particularly hazardous ( unlike the germicidal
>> ones used in UV erasers).
>
>What wavelength is required? I assumed they were the same.

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
 

Re: Building a UV PCB exposure box? - 2007-04-06 11:49:00

"Aly" <,s...@sliuflky4iuhdf.erl> wrote in message
news:Y...@bt.com...
> Hello,
>

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.



Re: Building a UV PCB exposure box? - Coyoteboy - 2007-04-06 12:36:00

"Aly" <,s...@sliuflky4iuhdf.erl> wrote in message 
news:U...@bt.com...
> "Aly" <,s...@sliuflky4iuhdf.erl> wrote in message
> news:Y...@bt.com...
>> Hello,
>>
>
> 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.
>

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



Re: Building a UV PCB exposure box? - Leon - 2007-04-06 13:03:00

On 6 Apr, 16:49, "Aly" <,shfskf...@sliuflky4iuhdf.erl> wrote:
> "Aly" <,shfskf...@sliuflky4iuhdf.erl> wrote in message
>
> news:Y...@bt.com...
>
> > Hello,
>
> 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.

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

Leon




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