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green
Member
Username: green
Post Number: 10
Registered: 09-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, 20 October, 2007 - 03:34 pm: | 
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I want to have a go at making an A4 sized UV cured ink printer, for printing PCB designs direct onto copper laminated board and am looking for a source of an 'off the shelf' mechanism. |
grab
Frequent Contributor
Username: grab
Post Number: 583
Registered: 05-2005
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, 22 October, 2007 - 11:15 am: |
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You're going to want a few things.
(1) Plotter/driller. These can be home-brewed if you're good with things mechanical - check the web for details. I'd recommend making this an auto-driller too, because that is *the* big time-saver in PCB making, and it'll also help you for setting up your UV printer with double-sided boards (otherwise it'll be very hard to get the two sides registered). Buying off the shelf is possible, but will cost you around £1000, which is why there are so many people making their own!
(2) UV source with collimated plotter-pen attachment (including a shutter to block the UV when you don't want it exposing stuff)). Probably home-brewable - UV sources for these IIRC are usually tungsten lightbulbs, and fibre-optic cables are cheap and readily accessible these days. For the collimation bit, you might be able to nick the optics off a laser pointer. And for the shutter, you might be able to cannibalise an old 35mm camera.
(3) Software. If you've home-brewed this, you'll need something which will take an HPGL file and send commands to your plotter to draw the pattern.
(4) Special photo-resist, or more software. Most pre-coated boards you buy, the UV-exposed resist is what's dissolved in the developer. You'll need resist which works the other way, so only the UV-exposed bits are left behind. Alternatively you could use some software to produce a "negative" of your design, but that's not as simple as it sounds, and commercial software which does this (for PCBs produced using milling) is quite expensive.
Graham. |
grab
Frequent Contributor
Username: grab
Post Number: 584
Registered: 05-2005
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, 22 October, 2007 - 11:17 am: |
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Actually, I just had a thought. I wonder - is it possible yet to get a UV laser diode? If so, I wonder if you could butcher a laser printer and replace its laser diode with a UV one? Then use the printer's own tractor feed to pull the board through. Of course, registration for a double-sided board is going to be *very* hard, but maybe you could use two printer mechanisms bolted together? |
green
Valued Member
Username: green
Post Number: 15
Registered: 09-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, 22 October, 2007 - 01:57 pm: |
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Hi Graham,
1. I have 95% of a CNC milling / engraving / drilling machine already done and also the 5 amp, 50 volt stepper driver boards too. You can see it at ..... http://homepage.ntlworld.com/moonshadow/New_Folder/engraving1.htm
It appears that I stopped work on it in 2006 when I realised that milling wasn't the answer for making PCB's. So off I went on the UV cured ink idea (along with millions of others). I had intended to finish it as an engraving machine for front panels etc, and probably will when I run out of other things to do.
2. Originally I had thought to mount a flexible fiber optic light guide onto the print head, which would have left me with the need of a shutter to stop stray UV light curing the ink in the print head nozzles. Now I am wondering if I can cure the ink after the printout and get distance from the print head. I would also like to see a flush cycle at the end of each print. It really depends how well the ink adheres to the copper, without 'balling up' and turning tracks into dotted lines.
3. I am not thinking of a plotter, because it would be too slow for what I have in mind. A flatbed printer would be ideal, but not easy to find at a reasonable price. I am waiting on some replies from China at the moment. Using an off the shelf printer means that the driver already exist for it, but a bit of jiggery pokery is required to activate cleaning cycles, print table return and home etc, but that can be done in hardware.
4. In this case we are printing resin on the parts of the board we want to keep after etching. The only thing that concerns me is how easy it is going to be to remove the cured resin prior to soldering !. However printers have provision for several cartridges, so I am thinking about one for the resin, one for the board graphics, one for solder masking etc .... so perhaps there is a solution there. One UV ink manufacturer offered a joint deal, so perhaps that problem could be left to them along with print head modifications for the UV ink.
This is not a commercial application. I want to give the PCB's away free. Just a matter of interest, the trend seems to be not to use a board but print a 22 layer design direct onto any substrata. Print layer, print insulation, print layer etc. Thanks for the reply.
Green |
green
Valued Member
Username: green
Post Number: 16
Registered: 09-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, 22 October, 2007 - 05:22 pm: |
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UV laser light array.
http://www.ncix.com/products/index.php?sku=16729&vpn=MD5LEDUV&manufacture=Logisys%20Computer |
conundrum
Regular Contributor
Username: conundrum
Post Number: 26
Registered: 06-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, 28 October, 2007 - 10:11 am: |
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or strip one off a bluray (iirc 395nm, will work quite well even though its not quite UVA) for about £25 off Greedbay.
best diodes are the ones from Nichia, they own.
watch drive current as these beasties are very fragile and static sensitive, far more than red LDs, i recommend soldering a 10k resistor and 0.1uf capacitor across them while the antistatic pad is shorted, then (and only then) unshort it. This was recommended in Sam G's Laser FAQ.
regards, -A |
obiwan
Frequent Contributor
Username: obiwan
Post Number: 1984
Registered: 12-2005
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, 28 October, 2007 - 11:46 pm: |
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I'd like to see the end results of this project though.....
Do Not Hit The Fly That Lands On The Tigers Head.
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green
Valued Member
Username: green
Post Number: 17
Registered: 09-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, 07 November, 2007 - 06:14 pm: |
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http://www.uvps.com/product.asp?code=UV+LED+++C |
segu
Just joined
Username: segu
Post Number: 4
Registered: 07-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, 15 November, 2007 - 01:43 am: |
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green
look at
http://www.aplomb.nl/TechStuff/PCB_s/UVsource_PCB.html
below some words from that webpage, I think next time I will try that way.
I will use an Epson Stylus Color 880 inkjet with overheadsheets to make the transparants
First step was gathering all the necessary stuff. More about that later.
As a UV-source I have two possibilities: a skin-tanner (LOL), or ..... UV-LED's
The spec's of these 5mm UV LED s
- Nominal current: 20 mA
- Voltage: Typ 3.60V DC
- Light power: Typ 2000mcd
- Light colour: UV 400-405nm
- Light angle: 15 degree ...... and that's why I think I need a diffusor of some kind
I started off with UV-LED's in a matrix of 4 * 6
Regards
segu  |
green
Valued Member
Username: green
Post Number: 19
Registered: 09-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, 15 November, 2007 - 10:10 am: |
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Hi Segu.
Thank you for the reply. Please let me explain where I am coming from. One day I was programming a PIC using Proton Basic and came to the conclusion that a child could do it. Unfortunately the child would not have access to a compiler, a development board, an RS232 converter etc., the cost of which would be far beyond the pocket money of a normal child. However I liked the idea and so decided to put together a book / CD to teach children about sensors, output devices and how to program a PIC to use them.
The main problem was to bring down the initial hardware costs to an affordable level. Logic says that the child could afford it only if it could acquire the software and hardware at a fraction of present prices. One way to do this would be to give the child all of the PCB boards free of charge. To cut costs further they would have to trim the boards and drill them. There only remained the problem of producing the blank boards cheap enough to give away. I decided that the answer was to print the PCB layouts direct onto copper clad board and then etch conventionally.
As the Dutch article points out normal solvent inks cannot be used because they take days to dry properly, without pre-heating the boards, which I did not want to do. Also the printed ink 'balls' up and turns printed tracks into dotted lines. This can be demonstrated by taping a bit of kitchen foil onto an A4 page and running it through an inkjet printer. So rather than use solvent inks I decided to look at UV cured resin inks .... which require a 'strong' UV source to cure the printed ink. Since the UV ink is a resin it is handling and acid proof. Some of the new ultrabrite inks may also work but either way, the application requires a flat bed printer. There is a video on You Tube that illustrates the basic flat bed printer.
http://www.youtube.com/watch?v=a14zELKPw8M
green |
segu
Just joined
Username: segu
Post Number: 5
Registered: 07-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, 15 November, 2007 - 03:45 pm: |
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Green
Maybe you checked that...
http://techref.massmind.org/techref/pcb/etch/directinkjetresist.htm
maybe help you, the article say 'cheaper' and 'precise' inkjet direct resist to copper
Regards
segu |
green
Valued Member
Username: green
Post Number: 20
Registered: 09-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, 15 November, 2007 - 04:16 pm: |
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Sequ,
Thanks again for the link. Yes I have looked at it earlier and have spent the last hour looking for an Epson C84 on EBAY. That and UV cured ink may be one solution. I am not too keen on Ultrabrite and a blowlamp . It would be nice to scrap the rollers too and use the paper feed to drive a flat bed table. I keep hoping that the real thing might come onto the market and save me the hassle of making one.
green |
terrym
Frequent Contributor
Username: terrym
Post Number: 527
Registered: 05-2005
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, 16 November, 2007 - 07:30 am: |
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I think I recall seeing something about the "real thing" somewhere recently. It may have printed conductive tracks on to insulating material directly - no etching at all.
TM |
green
Regular Contributor
Username: green
Post Number: 21
Registered: 09-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, 16 November, 2007 - 09:28 am: |
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A year ago one UV ink manufacturer told me that not only could they print 22 layers onto almost any surface, but that they had already started printing components, such as resistors and semiconductors, as well.
green |
dingbat
Member
Username: dingbat
Post Number: 10
Registered: 11-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, 27 November, 2007 - 05:50 pm: |
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Green, Hi there. What an amazing project . . . . er, but I wonder that you can make pcb's cheaper than a factory, I would suggest you get the project off the ground before investing a lot of time and effort into a side-show.
As I understand it your purpose is to let children program PICs. Put in "anyone" and I'm reaady to help!
If you are convinced children need to, then with the average child having a mobile phone by age 8, buying some of your kit isn't really an issue.
Picaxe uses a simple serial connection, so perhaps you should look at this.
If you concentrate on the project then the pcb-issue becomes irrelevant; your time is more valuable and making pcb's in quantity is difficult and very messy. Tinning, disposing of the chemicals - - - arrgh! |
green
Regular Contributor
Username: green
Post Number: 22
Registered: 09-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, 28 November, 2007 - 10:08 am: |
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Hi Dingbat,
Your points in order. One definition of an engineer is someone who can do for ten pence, what anyone else can do for a pound. I think the Chinese have taught us that lesson.
Yes I agree and decided to do the project write up first and I will worry about getting the PCB's made later. Perhaps by then I can by a UV printer off the shelf.
Ref para 2. Using lateral thinking, selling a course is not the only option, another is to give the whole thing away free. Last night I was looking at the African project to give every child a laptop. Looking closer to home, I think that any child here with engineering aspirations should be encouraged to pursue them. If they want to build robots and transformers, then so be it. Keeps them usefully employed if nothing else.
I decided to base the first book on the 16F877 because it was the only PIC with LVP that is allowed with the free version of the compiler. Besides which it is a lot easier to use than some of the smaller PIC's. The serial LCD and keypads also increase the number of available pins. I think interfacing is a large part of the project and I have included 20 different projects from the Blinking Led up to IR decoders etc.. I just need two hall effect devices to complete that part.
The software examples are largely written now and everything so far has been tested.
I decided I wanted lot's of illustrations and am doing the graphics at the moment. It is amusing because it is turning out to be the book I wish I could have bought years ago Hi!.
Green. |
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