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Old 15-11-2009, 08:39 PM
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kinetic (Steve)
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One Off PCB making at home

Hi,
I thought I'd just post some details about the success I have
had making Printed Circuit Boards (PCBs) at home.
Over probably 25-30 years I have made my own PCBs from
projects in EA and Silicon Chip magazines, producing one-offs.
I have tried just about all methods...the Positive resist photo-art,
Neg Resist, direct artwork and etch (decals and pen), but never
had much success with Toner Transfer method.
Many good articles describe it. Here are 2 good ones:
http://gilmore2.chem.northwestern.ed...garbz2_prj.php
http://www.fullnet.com/~tomg/gooteepc.htm

Anyway, my attempts years ago with Toner Transfer method
always were touch and go....I could never rely on fine details
to reproduce...SMD definite no-go...and even DIL ICs sometimes
had tracks joined and fine lines with pinholes etc.

Well my need to produce a quick, accurate one off a few weeks back
made me retry the TT method.

The success all comes down to the choice of printer paper as the
above links stress several times.

I thought I'd be smart and try normal A4.....pinholes, tracks lifted.NFG.
I then tried tracer paper A4......same..
Then I tried some good quality photo printer paper for bubblejets.
I used Kodak Picture Paper cat # 835 0613 on a HP laserjet (toner)
printer.
Outstanding success....the artwork was reproduced intact and etched
the best I have EVER etched an artwork...including with Riston processes.
I am so impressed with how faithfully it worked that I am confident
it would work with dual layer stuff and SMD.

I tried several re-tries so that I could demonstrate it wasn't a fluke.

The links above seem to infer that the method is not really for a
fine detailed project, but I now have every confidence that it is.

Attached is a board for my Stepper motor-focuser project.

I will try to do a step-by-step post with hopefully every method
I used if anyone is interested. Without wanting to duplicate the above
links, I may as well record what worked for me because it was so successful.


Steve
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Last edited by kinetic; 15-11-2009 at 09:57 PM.
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Old 15-11-2009, 08:53 PM
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This looks good.

I never succeded with TT.. however, plot (or laser print) on tracing paper (or even better, plastic foil for printers) in combination with boards with photopositive resist always gave excellent results.
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Old 16-11-2009, 07:39 PM
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That's as good as a bought one.

Thanks for the tip.
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Old 16-11-2009, 07:43 PM
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I have been messing around with putting a polymer layer on the cladding then etch the polymer off with Laser ,then Ferric chloride. Seems to work well.
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Old 16-11-2009, 09:29 PM
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Hi folks

About 2 years ago I was asked to investigate a method of printing a PCB layout directly onto the PCB laminate using an inkjet printer. A new $99 inkjet printer was stripped down and modified so that an A4-sized laminate could feed through on a flat tray. The modifications to the printer were relatively easy to do and the results were quite good.

Once the layer was printed, the laminate was baked in a low temperature oven to cure and harden the ink. This method can be used for 2-layer PCBs, so at this point the laminate can be returned to the printer to apply the 2nd layer on the flip side, if required, and baked again.

The PCB was then etched in Ferric Chloride. The document is a little too big to include here, but I would be happy to submit it for inclusion in the Projects and Articles section if there is any interest.

Cheers
John
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Old 16-11-2009, 09:42 PM
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Me again...

Just to give you an idea of the inkjet method, follow this link http://www.cnczone.com/forums/showthread.php?t=30951.

This is the article that I used to guide me originally.

John
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Old 17-11-2009, 05:45 AM
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Hi John, this is very interesting .. Please post your method, I will appreciate it very much :-)
I have tried this couple of years back, I still have this printer partly disassembled (Epson Stylus color 580, it has a piezoelectric printing head, and separate ink cartridges that could be reset via software ).. one day I may finish this project...
However, not every printer is suitable for modification, nor is every ink cartridge.. Sometimes there is necessary to fool the printer controller in thinking the paper is inside and moving, and some guys even added a separate controller to supply encoded pulses to do this.
Many cartridges have controller built in, they are not refillable and once they are emptied or replaced with a curable variety, they must be reset with special gadget (available for some types on ebay i think).
Some inks won't cure (the good ones are die-based, and apparently yellow one from Epson behaves the best when baked.)

I imagine the printers that print on CD's are more suitable...

As I mentioned earlier, the best results I had was with pen plotter (flat bed) and tracing paper (because one-off is almost never one-off, almost every time more than one board is needed) and photo-resist on copper cladded PCB.
Nowadays, the problem is HPGL plotter driver: while DOS drivers from older DOS layout editor programs (like Autotrax) work perfectly, they are useless with today's software packages..
On the other hand, the windows legacy HPGL drivers are supplied but not supported and all they produce are clogged pens and ink-splattered pieces of paper (they were never good, the plot files they produced were not sorted. The third-party drivers available at some time for Protel were pretty expensive and they are not available these days, at least I do not know about them. I am still considering writing my own, it should not be too hard, the program only has to read PCB file (in text format) and extract info related to tracks and pads and then it has to send this to plotter..
If anyone else is interested for cooperation, I can provide all my first steps and hacks in this direction: so far I managed to plot the pads, un-interrupted tracks are currently being worked on.

The printouts on transparency or tracing paper are good in principle, however, sometimes because of bad transport mechanism (rubber wheels) the plot is shrunk or stretched in the direction of paper movement.. so the outcome is uncertain, especially for double-sided boards.

Last edited by bojan; 17-11-2009 at 07:42 AM.
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Old 17-11-2009, 06:34 AM
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I just use the positive photoresist these days
Quick cheap and simple.
To make the plot, i just use a bog std bubblejet to output
the trace on std white paper at 2x size
I then manually touch up bits if reqd,
then go off to OfficeWorks and get em to photocopy it onto
film at half size and high contrast.
Works perfectly, is relatively cheap and you get to keep
the film for multiple use if reqd.

Andrew
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Old 17-11-2009, 07:51 AM
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Quote:
Originally Posted by AndrewJ View Post
then go off to OfficeWorks and get em to photocopy it onto
film at half size and high contrast.
Andrew
Reminds me of good ol' days when we used to make templates by sticking tracks and pads (letraset) 4:1 on special paper with metal core (pagra).
Then the company photographer would take a reduced size photo on high contrast fine grain graphic film sheet (I wish I could get hold of couple of them) with camera big as a smallish room (he could stick in A1 size film).
Ah, those were the days..
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Old 17-11-2009, 08:45 AM
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Hi bojan

Your comments on the inkjet printing method are quite correct and I found that only some printers and inks were appropriate. I used an Epson C87. In particular, the ink needed to be the DuraBrite pigment-based type. Yes, I found that the yellow ink gave the best result. When baked it was quite a good resist.

I had to reset the ink cartridge chips to fool the printer into thinking that it had a full complement of the colour cartridges, when in fact I was using 4 yellow cartridges. So, I was able to obtain full coverage of the one colour at the print head. I found that if you chose any blend of the primary colours that it effected the ink viscosity and surface tension and the results were not as good due to pitting.

As you will see in the document, I moved the paper detector so that it was able to detect the laminate carrier.

To AndrewJ:

Yes, Andrew, I too used the positve photoresist method many times when I first started making PCBs at home. I used to print the layout onto transparency sheets on a laser printer and then UV-expose the laminate, then develop & etch. We also used a more formal process at my work place. It was quite a successful method. These days I have access to a PCB mill, so the days of chemical baths are long gone (thankfully). You just tranfer the Altium (Protel) file to the mill and press the button!

Cheers
John
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Old 17-11-2009, 11:36 AM
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Gday John

Quote:
These days I have access to a PCB mill
Thats cheating

Andrew
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Old 17-11-2009, 12:39 PM
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Quote:
Originally Posted by Scorpius51 View Post
These days I have access to a PCB mill
Quote:
Originally Posted by AndrewJ View Post
Thats cheating

Andrew

And noisy and dusty.. (and I envy you )
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Old 17-11-2009, 09:17 PM
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Quote:
Originally Posted by bojan View Post
Reminds me of good ol' days when we used to make templates by sticking tracks and pads (letraset) 4:1 on special paper with metal core (pagra).
Then the company photographer would take a reduced size photo on high contrast fine grain graphic film sheet (I wish I could get hold of couple of them) with camera big as a smallish room (he could stick in A1 size film).
Ah, those were the days..
Oh yeah, I used to get paid huge money to do this, manually, WAY back, works of art they were, oh where is the ART these days
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Old 17-11-2009, 09:31 PM
AndrewJ
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Gday Freddy

Quote:
oh where is the ART these days
Its in "the eye of" photoshop, where else

Andrew
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Old 17-11-2009, 11:51 PM
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kinetic (Steve)
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Quote:
Originally Posted by AndrewJ View Post
I just use the positive photoresist these days
Quick cheap and simple.
To make the plot, i just use a bog std bubblejet to output
the trace on std white paper at 2x size
I then manually touch up bits if reqd,
then go off to OfficeWorks and get em to photocopy it onto
film at half size and high contrast.
Works perfectly, is relatively cheap and you get to keep
the film for multiple use if reqd.

Andrew
That used to be the main method for me too Andrew, but with
the need to make a one-off sometimes months or years apart
it usually meant a trip to Jaycar or DSE to stock up on
the essentials...(developer goes off in storage...need more
positive resist PCBs etc).

I would then get home...struggle to recall the optimum settings
and then proceed to use up half of the bloody new stock re-learning
those settings
UV light exposure....UV exposure when developer nearly depleted etc.
Does that ring a bell? Probably not if you're a high volume experimenter.

This method seems to be easily repeatable and has , so far, produced
great results every time.
Just have to jot down the details and maybe laminate it on an A4
printout and cable tie it to the FeCL bottle so I can find it in
another 12 months when I make the next one-off

Steve
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Old 18-11-2009, 07:28 AM
AndrewJ
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Gday Steve

Quote:
UV light exposure....UV exposure when developer nearly depleted etc.
Does that ring a bell?
Nup
I use Kinsten brand PCBs, so its just peel off protective cover and expose.
To expose, i sandwich the PCB between 2 glass sheets and go out in the sun. 10-15secs is all thats required.
( winter really stuffs up this method tho )

For developer, the Kinsten pack has an instruction manual
so you make a new brew every time.
IIRC, draino worked quite well as a backup to the "purchased" developer crystals.

Andrew
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Old 19-11-2009, 11:04 PM
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A few notes about the Toner Transfer Method:

Ok, so here is a detailed description of how this process works
for the benefit of making repeatable, one-off cheap PCBs.
Again, this process makes high detail artwork survive the etch
process faithfully, and therefore is a perfectly viable cheap method.
Not to take anything away from the pioneers of the idea who are mentioned
at the start of this thread.

1: Happy with the artwork?...I printed it out on a laserjet HP -5P
model using Kodak Picture Paper (for inkjet printers) A4 75sheets
cat #835 0613 (PIC 1)

2: I prepared a bare PCB with a light brush of a kitchen scour pad
with gentle strokes. (not steel wool because that can leave harsh scratches
that let etchant seep under resist material.)
Then, as per the supplied links, I gave the raw PCB a quick wipe with
paint thinner( or acetone) to make it as clean as possible.
Then I placed the printout carefully face-down on the PCB ready to iron
it on. (PIC 2)

3. Iron on highest setting, no steam...carefully put pressure over entire
area without sideways motion to avoid moving artwork initially.
Then the artwork 'glues' itself to the PCB allowing sideways motion
with the iron.
I found I could work the artwork using the tip of the iron (the hottest point)
and actually see the artwork appear through the bubblejet paper slightly.
(Pic 2 shows the artwork appearing after about 1 minute of ironing)

4. The PCB is very hot now and I dropped it into the kitchen sink filled with
warm water. After about a minute the backing of the bubblejet paper
can be carefully peeled off and it leaves behind the thin printout layer
still stuck to the PCB (PIC 3)

5. After very carefully rolling the printout layer with your thumb under water
you can remove all of the paper remnants until the artwork (toner) is left
intact.
Carefully inspect you have 'rolled' all of the paper off especially between IC
pads etc because if you leave ANY paper behind at this stage the etchant
will also leave that copper behind.
The toner survives fairly rough rubbing as long as it isn't scratched by a
fingernail etc.
PIC 4 shows the board ready to etch, alongside the original artwork
and a fully tested board.
Note as the pre-etch board dries off the tracks/ artwork take on a greyish
appearance. That is paper left on the toner/tracks.
That is perfectly ok....as long as it is not left on copper you want removed.

5. Etching.....(PIC 5) shows my small etching tank, fed with regulated
compressed air to speed up the process.
Pre-heating Ferric Chloride to above 30-40C also speeds it up.
Etching is complete in about 2-3 mins with good fresh FeCl.

6. All done....washed down, ready to use (PIC 6)

This method works!....bottom line is it works...reliably....minimal variables to
mess up success/failure....gotta be happy with that.

Steve
Attached Thumbnails
Click for full-size image (PCB_printout_laser.jpg)
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Click for full-size image (PCB_iron.jpg)
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Click for full-size image (PCB_kitchen_sink.jpg)
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Click for full-size image (PCB_ready_etch.jpg)
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Click for full-size image (PCB_etch.jpg)
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Click for full-size image (PCB_finished.jpg)
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Last edited by kinetic; 21-11-2009 at 06:13 AM. Reason: water was warm...not 'very warm'
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Old 20-11-2009, 06:31 AM
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wow Steve you have a nice etching tank with air bubbles :-)
I had access to this kind of tank at work 20 y ago.. when the pump stopped working one day (the type used in fishtanks) I simply let the board float on the ferrichloride solution surface, face down so to allow the whatever copper is turned into to fall down, this significantly shortened the etching time compared with the board laying face-on.

The alternative etching solution is H2O2 (30%) + HCl (conc) + water (1:1:1), much, much faster, couple of seconds (this can be controlled by amount of water added), the drawback is irritating gas released so this procedure is not for indoors. Also does not stain :-)

Anyway, nice and simple procedure you described here, I will try it on first occasion... I have a nice and compact PCB (Euro card format, 160x100mm) designed for Bartel's system for couple of years now (with heart-bit sensor) but the one I am using now (I made it on routing machine) is still working so, no real incentive to change it at the moment).
However, my EQ6 is in the queue to be bartelized one day.. so yes, I will have to do it one of these days :-)

Last edited by bojan; 20-11-2009 at 06:46 AM.
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Old 21-11-2009, 05:28 AM
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Thanks Bojan,

yes the etch tank I made years ago but the only downside is the
maximum board size it holds.

Air is delivered via a complex regulator system....a hose squeezed
with a G-clamp and a head tank of air from the compressor.

Etch takes only 3-5mins if the FeCl is above 30-40C so the air
flow doesn't change that much in that time.

Your board is on it's way. I will email you a layout etc so you're not
completely in the dark

The reliable process has now allowed me to think about a better
designed Bartels board as we discussed.
As you suggested , I think a series of daughter boards would be
a better approach.
There is always a negative though....When something works so
well it only adds to the long list of projects on the drawing board!
Isn't the ATM game fun!

Steve
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Old 22-11-2009, 04:27 PM
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kinetic (Steve)
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Here are some shots of SMD boards I made today using
the TT method. A rough LM335 test board.
The pattern shows an SO8 surface mount spacing.
Again, very fine line reproduction. Impressed!

The best part is when I can go from having the design on
screen....printout....etch in about 10 mins...sitting in
my hands ready to solder

Steve
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