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Topic: Toner Transfer - My First Shield (Read 4654 times) previous topic - next topic

cr0sh

I guess I wasn't too far off the mark with the "slop" remark...hmm.

;)

I still want to try my glass-panel process for UV positive exposure PCB making; maybe this summer...?
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P18F4550

I admit this method is quick n dirty Cr0sh but the results work, this method would be useful for batch processing, i had though about the UV exposure method but there is the argument over whether UV Leds give out as much UV radiation as a black light tube, im looking to attach a drill head to my Roland plotter and get it to pre drill the holes before the heat transfer process making alignment much easier and effective, there are improvements to be made. Thinking on i could make an A4 Sized UV Led board and give your oven idea a go.

cr0sh

I was actually thinking for the UV exposure part using double-ended metal-halide bulbs, rather than LEDs. It would run hotter, so I would probably need fans, but there would be plenty of UV generated, and it would be easier to build than using an array of UV LEDs.

My method for transfer of the toner to the glass, if it works (it should, based on everything I've seen), would just allow the glass to be reused, whereas with using transparency "paper", it can get expensive; plus by being a hard material, if you set things up right with the glass, you could get nearly perfect alignment. The downside on the whole process is that it is much slower; it would not be something that would scale at all.

Now I am getting visions of how to homebrew a PCB resist plotter and I must stop...

:D
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P18F4550

I used to use the plotter to draw circuits straight on the board but it had issues, like the pen scratching the tracks and also the plotter was set for certain pen widths so it didn't draw pads very well, i've even tried spraying the boards matt black and using a laser fitted to plotter to burn off the paint, this actually worked but the beam was so narrow at the focal point it would take a week to make any sort of decent layout, for now im sticking to the paper, it's perfect for single sided boards, even smd layouts, just takes a bit of care when doing double sided

SpikedCola

I prefer the UV method (print onto a transparent sheet, line it up, slide a sensitized board inbetween, expose, develop), but the toner transfer method is also a popular way of creating PCBs

cr0sh

Quote
I prefer the UV method (print onto a transparent sheet, line it up, slide a sensitized board inbetween, expose, develop), but the toner transfer method is also a popular way of creating PCBs


The problem with transparency sheets is that they cost so much; if you make a mistake printing one out, you may not catch it until you've wasted some expensive plastic.

I've heard that parchment paper used in baking is a UV transparent and cheaper alternative; my wife uses it for baking all the time, so I know that it is inexpensive by the roll, but I am not sure what sizes you can get it in sheets (probably standard commericial baking pan sizes, I would presume), but you would probably have to trim it to fit it into a laser printer.

Which is why I thought up the possibility of using pieces of glass, and transferring the PCB pattern onto the glass using an oven; this is something already done by people who etch glass - they transfer their pattern to the glass using an oven, then etch the glass with their chemicals, then remove the toner resist afterward.

Using glass as the UV masks would allow reusability while being inexpensive (not too mention you could easily make "standard" sizes with alignment holes for the PCB for perfect front/back alignments), the only problem is that it introduces an extra step in the process. If there were a way to easily get the pattern printed directly on the glass, it would be ideal.

Which led to me thinking about plotting/ink-jetting industrial sharpie ink onto the glass directly...

:)
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Osgeld

#21
Mar 15, 2010, 05:36 pm Last Edit: Mar 15, 2010, 05:36 pm by Osgeld Reason: 1
Quote
If there were a way to easily get the pattern printed directly on the glass, it would be ideal.


well if you can print on glass it would probably be more ideal to print direct on the pcb, which yes you can do with some model printers and inks
http://arduino.cc/forum/index.php?action=unread;boards=2,3,4,5,67,6,7,8,9,10,11,66,12,13,15,14,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,86,87,89,1;ALL

P18F4550

I tried Ink jetting straight onto a board, the HP DJ 400 draws paper straight through the printer so no bending is involved, as stock it will only take .8mm boards and needs modding to take 1.6mm boards, the obsticle i came across is that the ink is water based and as the print head boils the water to get the droplets it didn't work with endorsing ink which is permenent but not water based

KenH

There is a guy who has a copper product that is a very thin sheet of copper with adhesive backed.  He has a special coating to coat the copper with allowing a standard lazer printer to print direct to copper.  The copper is then glued to a blank FR4 board before etching.  You have to be careful about soldering temperatures or the adhesive tends to lift.

Darn if I can remember the place now - If anyone is interested I'll try to find it.  I like toner transfer method best now.  Photo method I'm told works really good, but the coated copper PCB stuff was too expensive for me.

Ken H>

cr0sh

Quote
Photo method I'm told works really good, but the coated copper PCB stuff was too expensive for me.


If you go with the pre-coated PCB material, then yes, it is pretty expensive. What you can do, though, is get the positive resist material in powered form and mix it up with water, which is enough to coat many boards (regular PCB material), and it isn't really expensive.
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DeFex

#25
Mar 17, 2010, 04:50 pm Last Edit: Mar 17, 2010, 04:58 pm by DeFex Reason: 1
Just a hint, you can print to PDF with "dopdf" and then import it to photoshop or something with 1200 DPI, then when you print there are no jaggies (and you can edit the board some more with nicer text, and smoothing or what you like.)

here is one done with pulsar pro toner transfer/ hp laserjet and laminator
(http://4.bp.blogspot.com/_cmcUouqPLaA/S3m45iMqWLI/AAAAAAAAAFU/1n5XkrPR62U/s1600/board.jpg)

well done on the double sided as well, now i think i will have to give it a try on my next board, i spend way too long trying to be clever and getting single sided to work with minimum bridges :)

I still think someone should make laser sensitive CD shaped blank PCBs you could have a coating that gets burned by lightscribe, then you could make small (or larger with a hole in them :D) or round PCBs right in your rarely used CD/DVD burner!

P18F4550

Hi Defax,
The Jaggies are a result as you mentioned of low DPI, How do you scale pdf's, the last board I printed from pdf was out of scale, it was too small.

If I up the dpi at print time will that affect the scale or just make the layout smoother?
Your board looks smooth, no jaggies, and well designed, my first prefrence is for single sided, there is occations that call for double

DeFex

#27
Mar 18, 2010, 09:25 pm Last Edit: Mar 18, 2010, 09:25 pm by DeFex Reason: 1
well i "printed" it from expressPCB, the important thing is that when i import it, do not touch the dimensions at all, just change the DPI(when importing, not printing). then for me it just prints out the correct size.

however i do not have any idea if pcb wizard scales the PDF properly, i have never used that program.

frostin

I design my board in eagle then I take it from there and print it from gsview on transparency paper. The process I do takes a bit but uv can get way better results than transfer. The hardest part of toner transfer is making sure it gets heated evenly. Problems I had was some of the traces lifted off. So I built a uv light box (posted here on forums). I did a double sided pcb but I forgot I had to cut it with a dremel cause aviation shears cracked the board... I'm so used to using single sided and no dremel is needed because aviation shears work real well with them...

P18F4550

As a final footnote, this process seems to be working well now, better still Tesco have dropped the price of the glossy photo paper to under £2 for 20 sheets, im now using a heat Sealing http://www.grimsbymodelcentre.co.uk/public/content/Product.aspx?ProductID=223 , something aero modellers use for covering aircraft, it has no steam ducts and the hotplate is an even temp all over unlike a clothes iron, it heats up to 160 degrees C now i know that the ideal temp for toner is 190 degrees C but it seems to work ok and i figure i dont want to make the toner liquid just make it sticky so im sticking to 160, also just out of interest i tried toner transfering the silk screen artwork to the board after etching and im pleased with the results. i'll maybe post a pic.

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