Help me make a PCB UV Exposure Box

[MCMC]

Hi all

Anybody making your a home "PCB UV Exposure Box" ?

I to plan make one, any sugestions or help about circuit or cabinet construction is welcom !!!

 

[FoxyRick]

pcb uv box

I spent quite some time making one. It took a while because I made a wooden case - I'm not good with wood!

Having finished it, I came across a perfect alternative case - an old scanner. If you can make do with a single-sided box, an old scanner case is absolutely ideal. The modern ones are a bit shallow. A nicely-fitting hinged lid is built in, as is a beautifully flat glass plate. Perfect size for 4 to 6 12-inch tubes and ballasts. I wish I had found it sooner... If you can get your hands on one (mine was free - faulty), use it.

Anyway, mine is a double-sided, 10mm MDF frame, hinged at the back and with all the ballasts and timer in tha bottom part. It weighs a bit, but is quite compact really. Exposure area is 28cm x 16cm with four tubes on each side. Exposure time is 10 minutes with microtrac presensitized board.

I chose 10mm MDF as it is easy to work and stiff enough not to bend and distort the glass plates. The whole case is made from this, screwed and glued together.

The best material for the 'glass' is 6mm acrylic (plexiglass, lexan); polycarbonate (perspex) is not as UV transparant. Some types of glass are better than others; standard window glass can be quite poor for UV use. Many people say it does not make much difference though. Glass might be easier to work with (if you get it cut to size) as it is stiffer than the acrylic and won't distort as much if the case is not perfect.

The most difficult and time-consuming part was making sure the two acrylic plates were perfectly flat and true to each other. The most vital part of making the PCB is getting the artwork perfectly flat to the board. Otherwise, the traces get blurred out and undercut. It took about 12 hours of gentle sanding of the MDF supports to get it just right. If you are making a single-sided unit, this is much easier as the foam-backed lid will take care of it.

The unit works perfectly; I can make boards for chips with 0.5mm pitch pins reliably. This is due to planning, attention to detail, patience and perseverence - not to my (lack of) woodworking skills! In other words, anyone can do it if I can.

The tubes are about 2cm from the 6mm acrylic plates. The inner is lined with tin foil. I have read about using a fine grill between the tubes and screen, with the effect of collimating the light so that undercutting of the tracks does not occure. I have not found this to be an issue though. Maybe when I need to make 0.25mm pitch traces(!)

I might make another when time permits, mainly for sake of even more compactness. I have in mind a vertical, cassette-loading unit. The board would be put into a simple, hinged, two-sided acrylic holder that is clamped shut. This is then inserted downwards into the UV unit, in simple guide rails, that has UV tubes either side. Should actually be easier to make, especially with regard to holding the artwork and board flat. I might even add rubber edges and a vacuum take-off to really get that artwork pressed onto the board.

Seriously, if you are making a single sided unit, find an old scanner. I you want more details about mine, ask and I might be able to draw you a sketch, although my drawing is worse than my woodwork.

I also built my own heated foam etching tank, interested???

Good luck with the build,

FoxyRick.

 

[leemarrow]

uv pcb exposure box

Hi,
if you understand italian language go to:
http://www.geocities.com/mrardj

 

[gam]

pcb uv light box

I built one out of wood also. Very simple, a small box with the top on hinges by the sides.

Two blacklight lamps are inside the box and a 3mm glass sheet resting on side supports about 2 cm below the top cover.

I have 0.5 mm tracks but only if there is dummy copper pour around it. Otherwise overetching occurs everytime. I am not sure wether this is from the exposure time or the chemicals or maybe the mask is not tightly pressed on the glass aspointed by foxy-rick.

I will need to do some more tests, trial and error is almost the only way to get your own working method in PCB .

I am interested in your heated etcher tank, thanks for sharing.

Regards,

Gam

 

[MCMC]

pcb uv exposure unit buy

FoxyRick and leemarrow its information is of great aid,

I have already a old scanner to modify it, but I want to build a for "double side" and doing it with base and plates in aluminum seemed to that of the photo

help on any circuit like timer and balast for lamps ?

 

[Cluricaun]

uv exposure boxes

Hi

I built a UV-box made of aluminium frame and thin stainless steel as top and bottom. Similar to this http://www.proma-technologie.com/deutsch/rundum_l/produkte/Chemie/pdf/vakuvbel1.pdf

As ballast I just used ordinary ones, there are special ones for Philips UV tubes, but I do not think it is neceserrry, try to find similar.

Here are some timers, none built by me yet but will try the last one.
http://www.geocities.com/b94_1999/exptimer.htm
http://www.geocities.com/b94_1999/progetti.htm
**broken link removed**

I have to come up with a clever design to align the two printouts for top and bottom layer, any suggestions welcome. Should be possible to align then placing the PCB between the two wothout any distorted image or scew.

How to connect the baluns in series or so are quite straight forward. Tell me if more info is needed and I try to help.

Cl

 

[MCMC]

uv exposure box ballast

hi Cluricaun

I have to come up with a clever design to align the two printouts for top and bottom layer, any suggestions welcome. Should be possible to align then placing the PCB between the two wothout any distorted image or scew.

use the following method to registry the 2 printouts

Your information is very usefull !!!

 

[jackrs]

uv exposure pcb

Hi MCMC !!!


Look at hxxp://www.electronics-lab.com/articles/index.html
(change xx to tt)

Go to iten .CB and you see some articles (projects) about UV exposure box to PCB.

Enjoy.

jackrs 8)

 

[bogdanm]

proma uv exposure

WRT the previous post, this is probably what you're looking for:

hxxp://www.electronics-lab.com/articles/uv_box_fluo/index.html

A quite complete project.

 

[MCMC]

uv exposure box pcb

hi all

a good photo in how to hookup a wiring of lamps, and some links !!!!

this is a video link in how to registry the sheet and a use of the uv exp box for double side pcb
hxxp://www.bungard.com/videos/bungard_hellas_engl_quartersif.mpg

hxxp://www.electricstuff.co.uk/pcbs.html
hxxp://www.users.bigpond.net.au/vk3yng/pcb/making_pcbs.htm
hxxp://www.atm-workshop.com/light-box.html
hxxp://www.thinktink.com/stack/volumes/voliii/equipment/uvlamp/uvlamp.htm
hxxp://www.thinktink.com/stack/volumes/voliii/equipment/uvlamp/uvhookup.htm

 

[FoxyRick]

exposure box

A note about ballasts and starters... and note that I am in the UK with 220V mains...

I bought ballasts from Farnell rated to run two 12 inch tubes and wired them according to the standard (shown in the ballast's datasheet) with the two tubes in series with the ballast and a starter across each tube.

The tubes just would not start, ever. I have been told (not checked it yet) that you need starters for 110V if doing this, not the normal (UK) ones which I assume are 220V. I have not seen this written anywhere, it may not be right, but my tubes certainly did not start when wired correctly according to the datasheet.

Check this before you buy if wiring tubes in series.

I solved the problem (after swearing a lot and thinking I needed a bigger case for eight ballasts) by removing one starter from each pair of tubes and inserting a 220nF X2 suppression capacitor instead. The tubes start OK now, but I'm not sure what this will do to the tube life.

A good reference for fluorescent tubes and drivers:

https://www.repairfaq.org/sam/flamp.htm

Cheers,
FoxyRick.

 

[flatulent]

uv exposure box timer

There is also the safety issue. Make sure that the light does not leak out of the box and come within your vision.

In the old days hobby people used the sun.

 

[Cluricaun]

made uv exposure case

Hi

Yes thats correct, I forgot to mention the starter issue. If connected in series you must use the starter intended for it, I use TLD 15W/05 from Philips and the started S10 4-65W from same company. I undestand that not all can get Philips but comapre tech data at Philips with products from other company ie Sylvania.

Issue is quite important here, it is not harmfull if accidentally look into the UV-A (365nm) but not a good idea to spend to much time in same room. The same tubes are often used ín food industry to atract insects, HV grid around the lamp kills them but in these occations the lamps are not placed right infront your eyes and many meters from where you normally are. So please make a proper box and do not look directly into the UV light, it is much better for your eyes. There are protection glasses but I think it is a little "overkill".

I do not know if it is openable:
hxxp://www.prismaecat.lighting.philips.com/LightSite/Whirlwind.aspx?eca=LEPPLG&cpf=SEEPSV&stg=ACT&lan=EN%20&ecu=LMP%7cPHL%7cEP&cnt_key=START+++%7cPHL%7c871150076499728+++&t=3&tree=0&scr_md=1111#

hxxp://www.prismaecat.lighting.philips.com/LightSite/Whirlwind.aspx?eca=LEPPLG&cpf=SEEPSV&stg=ACT&lan=EN+&ecu=LMP%7cPHL%7cEP&cnt_key=TLD8++++%7cPHL%7c871150070279140+++&t=3&tree=0&scr_md=1111#

Cluricaun

 

[kasamiko]

uv exposure box circuit operation

Can I use an ordinary DAYLIGHT Fluorescent lamp instead of specified UV/Blacklight lamp?? Do you think I can get the same results?? :?:
I used to exposed the pre-sensitized pcb under the SUN for 30 seconds and always get an excellent result.. 8O
You might ask.."Why bother to make the exposure box??" Simple, just in case the SUN might not SHINE someday..

 

[FoxyRick]

making a simple pcb uv exposure at home

I used to use a twin-tube caravan light with standard 12 inch fluorescent tubes - exposure time was about 15 minutes with cheap presensitized board held about 1cm away from the tubes. The lights always made my eyes ache though...

With regard to looking at the UV tubes, UV-A is OK for the usual PCB exposure times, UV-B will cause eyestrain (like snow blindness or welder's flash) after a while, UV-C causes cancer and blindness but is only used for EPROM erasing or killing germs in air/water. I have seen plans on the internet using UV-C tubes for PCB exposing - don't do this.

Cheers,
FoxyRick.

 

[checkmate]

making uv exposure for pcb at home

Seriously, if you are making a single sided unit, find an old scanner.

Hi, just want your opinion if standard scanner glass is ideal for uv exposure. I've built a unit from a faulty scanner, but havent quite tested it out yet.

 

[FoxyRick]

uv plexiglass box

Hi Checkmate,

Standard scanner glass is probably not "ideal", but if you are using UV tubes I imagine it would still work very well.

Standard window glass is designed to reduce the amount of UV light, I don't know if the same glass is used in scanners.

Even if it is the same, With the tubes and artwork so close, and the glass is only 3-4mm thick, it should be fine.

Many people I have talked to have just used normal glass with no problems (they didn't even know about it blocking UV).

My problem is that I tend to be a perfectionist, and waste endless hours getting an extra few percent performance. It doesn't usually matter in the real world...

Cheers,
FoxyRick.

 

[alphi]

pcb philips lamp uv

Anyone can suggest some home pcb making method?

 

[aslm]

blacklight pcb exposure

There has been several threads talking about making PCBs, one of the more informative is this on, i think:


Would also recomend this site:
https://www.electricstuff.co.uk/pcbs.html

Making my pcbs at home at the moment, reading electroda while waiting for UV to be done

regards Me

 

[siongboon]

uv pcb scanner box

website for reference....
**broken link removed**