Making a UV exposure box, Help with Bulbs please :) - Page 1
Forum section: electronics / projects

author: CpHarding
author_rank: Contributor
timestamp: April 18, 2012, 12:28:59 pm
content: Right, had the Idea of making a UV exposure unit, I've ripped apart an old 3 in 1 printer, and i'm using the scanner area as the case for this ( closing lid, and large ( A4) glass panel.)I ordered some bulbs off ebay, and suitable holders for them, thinking they would be the same as CFL's and all I would need to do is apply power. Seems I was wrong.http://www.ebay.co.uk/itm/160701358433?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649here are the bulbs.I'm not sure how to drive them. A dismantled CFL board managed to power a single bulb, but I couldn't find another CFL board that would work, and ideally I would want to use all 4 bulbs.Any ideas?ThanksChris

author: Spawn
author_rank: Frequent Contributor
timestamp: April 18, 2012, 12:56:36 pm
content: Those are PL or PL-C bulbs, they work same as a fluorescent bulbs and you need a ballast to make it work, some of them even needs a starters just like fluorescent bulbs.Why not get one of those old scanners (high ones from 90’s) and use UV fluorescent bulbs? Easier to make and more equal light.Here a idea with a lot photosHit F5 if pictures are small.

author: free_electron
author_rank: Super Contributor
timestamp: April 18, 2012, 01:40:42 pm
content: Not sure what the wavelength is of those. You need 450 nm for pcb's ... Aquarium lamps work fine....As for glass : bad idea. Glass blocks uv... Get a piece of lexan or plexiglass. Make sure it is the frosted white type. That way it acts as a diffuser.

author: CpHarding
author_rank: Contributor
timestamp: April 18, 2012, 02:08:08 pm
content: Quote from: Spawn on April 18, 2012, 12:56:36 pmAs there is only two terminals per bulb, I can't use a fluorescent starter ( as far as i'm aware). Is there a commercial ballast I could buy, or even a circuit diagram of how to create one available? Ideally I would like to use the bulbs i've got.Quote from: free_electron on April 18, 2012, 01:40:42 pmThese are designed for nail dryers apparently, which ( according to the electronics genius where I work) will work fine on PCB's. Good advice on the glass, I will have to experiment with what i've got, I do have some perspex kicking around if needed.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: April 18, 2012, 02:20:13 pm
content: Glass is fine for a PCB UV box - glass only blocks short-wave UV.Glass is better than plastic, as it's more rigid and less susceptible to scratches. Some plastics also go cloudy under prolonged UV.

author: Spawn
author_rank: Frequent Contributor
timestamp: April 18, 2012, 02:41:30 pm
content: Quote from: CpHarding on April 18, 2012, 02:08:08 pmStarter was just a exampleGoogle for a PL Ballast, there is some information on this pagehereThe bulbs you ordered are 365nm Wavelength but i am not sure if that is a problem, scanner glasses are good, a lot people use old scanners and never heard something wrong about it, i guess they would be coated or worked with something to let the scanning light get through it anyways.EDIT: Here some on Ebayhttp://www.ebay.com/sch/i.html?_nkw=pl+ballast+2p&_sacat=0&_sop=15&LH_PrefLoc=2&_odkw=pl+ballast&_osacat=0&_trksid=p3286.c0.m270.l1313

author: SeanB
author_rank: Super Contributor
timestamp: April 18, 2012, 03:46:57 pm
content: Those lamps have a built in glow starter, in the square box between the 2 pins.To drive them is simple, just go down to an electrical wholesaler and buy magnetic ballasts for them. If you live in an area with 110VAC mains, you need one 9W ballast per lamp. The lamp is wired in series with the ballast. Easy, as there are only 2 pins per ballast. For 220V areas you can do the same, using 9W ballsts one per lamp, wired the same way in series. A common thing in 220V areas is to place 2 lamps in series, and drive them with a 20W ballast in series with them. Saves 2 ballasts. This works because the lamps drop roughly 55VAC when running ( but have to be fed from a constant current source, as the voltage varies according to lamp temperature and age, but they are around 55VAC most of the time) and needs 90VAC to start, so 2 of them will start reliably on 220VAC, but not on 110VAC.

author: CpHarding
author_rank: Contributor
timestamp: April 18, 2012, 05:53:47 pm
content: Brilliant Thanks guys

author: wkb
author_rank: Super Contributor
timestamp: April 18, 2012, 07:09:14 pm
content: I went to the local 'recycling shop' and bought myself one of these UV-A "head tanning" thingies.For 5 bucks I had everything in one go: 5 UV-A TL tubes, starters, ballast, enclusure. Easy does it. A pieceof plexiglass to press the layout onto the PCB and off I wentI have a halfbacked plan to get an old flatbed scanner and move the tubes etc into that one. That would perfect things.

author: Spawn
author_rank: Frequent Contributor
timestamp: April 18, 2012, 07:45:36 pm
content: I got an original one specially made for this and to be honest a good self made one will work just good as mine.This is the model I got, with 4x 15W and the start button is red not black as the one in the picture

author: CpHarding
author_rank: Contributor
timestamp: April 19, 2012, 12:20:45 am
content: This is kinda a side project i'm working on as a break from revision, although I'll post some pictures when i'm done. finished my final year project report at Uni in an Electronic engineering degree todayjust three exams to revise for and i'm free! then I can devote more time to this project, oh and job hunting of course!

author: notsob
author_rank: Frequent Contributor
timestamp: July 07, 2012, 03:59:25 pm
content: I remember reading about a member using UV leds for exposure, - but had them on a 'raw' board. This complete project may be of interest.http://en.elektronicastynus.be/projects/81/

author: hlavac
author_rank: Frequent Contributor
timestamp: July 07, 2012, 10:11:13 pm
content: I got UV LEDsin my exposition box.

author: Zero999
author_rank: Super Contributor
timestamp: July 08, 2012, 10:01:52 am
content: Quote from: free_electron on April 18, 2012, 01:40:42 pmNo, 450nm is in the blue region of the spectrum. He's got the right wavelength, 365nm is perfect for PCB exposure.QuoteNo, glass doesn't block all UV wavelengths, only the shorter UVB to UVC end. Glass allows the longer 315nm to 380nm wavelengths required to develop PCBs though.Those tubes are perfect for the application, all he needs is a suitable ballast. If the mains voltage is 230V he could probably use just two ballasts and wire them as series pairs. They are much easier to wire than linear tubes because the starter is built-in so all they need is to be connected in series with the ballast.

author: ElektroQuark
author_rank: Unknown
timestamp: August 14, 2012, 03:31:15 pm
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