The photo material used on PCBs is designed to accept what is known as "actinious " light, with a wavelength of appx 370-380 nM. Although other light sources as e.g. sun light will or may work, you are best off with buying specialy deisgned lamp sources. A tip- light bulbs sold as disco black lights will also work...
Ok!
Check my UV page (you may need altavista to translate)
The 4 lamps cost me 35€.
I think it's cheap making PCB's with UV lamps...
Check my UV page (you may need altavista to translate)
The 4 lamps cost me 35€.
I think it's cheap making PCB's with UV lamps...
AuroraB said:
These lamps will NOT, I repeat, NOT work! Save yourself the trouble of going back to the store to ask your money back.Black lights emit UV-B light if I remember correctly, the UV light needed for PCB boards is UV-A.
Lamps that can be used for this are lamps from a tanning device.
This is probably the cheapest way to get good lamps. Just go to a recycling store and buy yourself a tanner (correct word?).
I bought myself a tanner with 6 UV lamps in it for only 5€! It works great and it's so big that if I wanted to I could make PCB's of 1.5m * 50 cm
.
8 minutes
about 5 years ago I took a photographic densitometric step tablet and used it to measure the optimal exposure -- for my light box (which also serves as a light table for examining negatives) it turned out to be 8 minutes
developing is a little trickier -- if you are using NaOH you should play around with various time and temperature combinations -- if you are using a less polar developing agent it becomes less critical. in the U.S. I have used drain cleaner when (Drano) when I ran out of NaOH.
you can do the developing using a red safelight -- then examine the board under white light turned on for a few seconds. if you are using NaOH wear rubber gloves.
about 5 years ago I took a photographic densitometric step tablet and used it to measure the optimal exposure -- for my light box (which also serves as a light table for examining negatives) it turned out to be 8 minutes
developing is a little trickier -- if you are using NaOH you should play around with various time and temperature combinations -- if you are using a less polar developing agent it becomes less critical. in the U.S. I have used drain cleaner when (Drano) when I ran out of NaOH.
you can do the developing using a red safelight -- then examine the board under white light turned on for a few seconds. if you are using NaOH wear rubber gloves.
The presensitized posative process PCB sold by PartsExpress will form a nice image with just an ordinard 100W bulb hung in cheap relector about 12 inches above the board. Exposure time 7- imutes. With boards larger than 5in x 5in it works better to hang the lamp a bit higher and expose a bit longer. Use an inverse square calculation to estimate the time when hanging higher.
I've done enough boards this way that i've lost count.
I've done enough boards this way that i've lost count.
I just recently got a flourescent daylight bulb. It fits in a normal light bulb socket and is rated at 23W. It is very bright, like you can face it towards the opposite wall and still read a book no problem. The last board I made I mounted the light 7 inches above the board and exposed for 6 minutes, but I overexposed it. I'm not sure if it was due to too much exposure time or the fact that my crappy ink jet printer didn't get the transparency mask dark enough. I think its the latter. I've tried to run the transparency through the printer a few times, but often it doesn't line up correctly and totally ruins it. Unfortunately as far as making boards goes, I've never had much luck although I've done a few correctly. I've wasted so much money, but I see no other option. Hopefully I'll develop a technique that works, because my next board will be a double sided one too.
Pete
Pete
cm961 said:
Good to hear, maybe I won't need to buy UV tubes then. BTW,
we don't regularly have the daylight bulb here. I asked in a local
shop and they had made a special order from the US for a photo
lab, but they didn't find them good, so they stuck to the tubes.
I was about to tell you to run the mask through the printer
several times, Slone recommends that, but many inkjet printers
are crappy. You might consider getting BW laser printer, then
there will most likely be no need to run it several times. There
are som cheap, althoug somewhat crappy laser printers, but
they will probably do the job. I used to have a cheap OKI. It printed
very well, but had no internal proccessor, so it hogged down
my PC. Not much of the problem for an occasional PCB. Eventually
it started to give me probelms with paper feed and printout
quality, so I got a more expensive printer, a Brother, which still has never
let med down for the three or four years I've had it. Ah yes, it
is so fast compared to my OKI, so when I think I can go away and
brew a cup of coffee while it is printing out a thick manual or
something, I usully won't be finished with the brewing until
it starts beeping cause it's out of paper.
. Still, something like
the OKI might do if you don't use it too heavily for other printing
too.
Disco black lights does not emit UV-B, - or should not - at least...
UV-B is hazardous and should be avoided, almost at all cost..
50 cm tubes are in the market in Scandinavia, called TLA-15 by Osram, but- I wil check the number tomorrow at work, and repost.
2 of those in a ordinary 50 cm lamp does the job, even one for PCBs up to 10-15 cm wide.
Most light sources, except discharge lamps, will have broad spectrum output,, and give some emission at the desired wavelength, but you are much better off with proper light sources.
The double or triple transparency prints work OK, but there is a product on the market called Laserstar, which does an excellent job as a carrier film for printers. However- this product looks and feels very much like the plastic drawing film used for tech drawing in the 70s and 80s before plotters became cheap...
Try an architects office or something, - this product must still be available..??
UV-B is hazardous and should be avoided, almost at all cost..
50 cm tubes are in the market in Scandinavia, called TLA-15 by Osram, but- I wil check the number tomorrow at work, and repost.
2 of those in a ordinary 50 cm lamp does the job, even one for PCBs up to 10-15 cm wide.
Most light sources, except discharge lamps, will have broad spectrum output,, and give some emission at the desired wavelength, but you are much better off with proper light sources.
The double or triple transparency prints work OK, but there is a product on the market called Laserstar, which does an excellent job as a carrier film for printers. However- this product looks and feels very much like the plastic drawing film used for tech drawing in the 70s and 80s before plotters became cheap...
Try an architects office or something, - this product must still be available..??
Blacklights
Blacklight fluo tubes are the right ones for the job.
You have two types - blacklight (BL - with white coating, looking like normal fluo tubes) and blacklight blues (BLB - with blue-violet glass used to block most of visible light) that are mostly referred as disco blacklights.
They have UV peaks at about 370nm, (if I remember correctly) and I'll try later to find some datasheets from Philips and NEC to prove that.
Presensitized pcbs are most sensitive to near-visible UV light, here's some links:
Bungard and
Injectorall
Maybe there are some types of photoresists that are more sensitive to other wavelenghts, but these ones (for home use) are happy when you light them with 350-400 nm.
I use cheap Chinese $2 BLB's, laser printed drafting paper (if that's what's known in Germany as Paus Papier - semitransparent waxy paper), some unknown brand of presensitized pcbs, exposure time 6-7 minutes and it works great - no problem with 10mil traces. (don't have a digicam to show the results)
Blacklight fluo tubes are the right ones for the job.
You have two types - blacklight (BL - with white coating, looking like normal fluo tubes) and blacklight blues (BLB - with blue-violet glass used to block most of visible light) that are mostly referred as disco blacklights.
They have UV peaks at about 370nm, (if I remember correctly) and I'll try later to find some datasheets from Philips and NEC to prove that.
Presensitized pcbs are most sensitive to near-visible UV light, here's some links:
Bungard and
Injectorall
Maybe there are some types of photoresists that are more sensitive to other wavelenghts, but these ones (for home use) are happy when you light them with 350-400 nm.
I use cheap Chinese $2 BLB's, laser printed drafting paper (if that's what's known in Germany as Paus Papier - semitransparent waxy paper), some unknown brand of presensitized pcbs, exposure time 6-7 minutes and it works great - no problem with 10mil traces. (don't have a digicam to show the results)
Thanks for all the replies.
Did a search last night regarding blacklight at the osram website.
(www.osram.com) I found this boulb: (Blacklight)
HQV 125W E27 12X1
You can find it under:
Catalogue/ Lamps for General Lighting/ Special Lamps/ UV-Lamps HQV lamps and black glass fluorescents
At osram.
You think this will work?
Did a search last night regarding blacklight at the osram website.
(www.osram.com) I found this boulb: (Blacklight)
HQV 125W E27 12X1
You can find it under:
Catalogue/ Lamps for General Lighting/ Special Lamps/ UV-Lamps HQV lamps and black glass fluorescents
At osram.
You think this will work?
If you want to buy lamps/ tubes for PCB this is what you need:
http://www.elfa.se/elfa/produkter/no/2013692.htm
Don't buy a black light tube or bulb.
This the complete unit, - a bit costly for hobby use...
http://www.elfa.se/elfa/produkter/no/162391.htm
I have been using units like these for 30 years....
Otherwise, - the part is TLD15W/05 ( or the smaller TL8W/05).
The 15W version fits any 50 cm norwegian lighting fixture.
2 of these in" standard dobbel kjøkkenlampe" does an excellent job!
http://www.elfa.se/elfa/produkter/no/2013692.htm
Don't buy a black light tube or bulb.
This the complete unit, - a bit costly for hobby use...
http://www.elfa.se/elfa/produkter/no/162391.htm
I have been using units like these for 30 years....
Otherwise, - the part is TLD15W/05 ( or the smaller TL8W/05).
The 15W version fits any 50 cm norwegian lighting fixture.
2 of these in" standard dobbel kjøkkenlampe" does an excellent job!
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