
Researchers create rollerball-pen ink to draw circuits - ph0rque
http://www.physorg.com/news/2011-06-rollerball-pen-ink-circuits.html
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NonEUCitizen
Conductive pens are already available and used for circuit board repair (I
think resistance is too high for long traces), e.g.:

    
    
      http://www.circuitspecialists.com/8420-p.html
    

If you check the PCB forums, people are always toying with the idea of hooking
these up to a plotter for DIY circuit boards without needing etching
chemicals.

Presumably these researchers have come up with a better one (probably more
consistent flow).

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ajdecon
A big part of this is the more consistent flow, yes. Two of the major factors
in the ink design were balancing the viscous properties of the ink (mildly
shear-thinning, iirc) with the need to keep the silver nanoparticle
concentration as high as possible.

(Disclaimer: I am a former member of the Lewis group, but didn't work on this
project myself.)

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NonEUCitizen
Do you know if they are also much more cost effective than existing pens ?

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ajdecon
No idea, as no commercial-scale production has been attempted. This is all
still lab-scale.

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jws
It appears to handle reasonable amounts of current, it can drive an LED over
about 10" of trace in the LED grid example. That example also has cross overs,
though they don't mention it in the article.

I wonder how they bond the components to the traces. Is setting them on fresh
ink sufficient?

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ajdecon
I used to work in the lab in question, though nowhere near this project. (And
I'm ridiculously proud of my colleagues right now. :D )

To answer your question, setting the components on fresh ink is often
sufficient but not always. IIRC, components were often put in place and then
"drawn over" a second time with the pen, or small beads of ink were put in
place.

I saw cross-overs demonstrated simply using normal white-out (!) after the
first trace was dry, but I no longer have access to a journal subscription so
I'll have to bug my colleagues for a copy before I know if that is what was
used in the publication.

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regomodo
This has given me an idea: an etch resist pen in a plotter-like setup. It's
about time I use the steppers i pulled out of old Epson printer and use up
some of my copper-clad boards.

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ChuckMcM
This struck me as non-novel since the CircuitWorks pens have been around for a
while. But the ability to write on a flexible medium and bend it etc is the
news here.

There are a number of uses for something like this, if its economical. I hope
they can commercialize it.

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gcb
Nothing that couldn't be done with 30's era conductive paint.

granted you have to use a small brush to apply...

...and i still think "soldering" leds to a piece of paper is ... wrong.

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sn
There's already the paper-based mobius circuit:
<http://www.evilmadscientist.com/article.php/mobiuscircuit>

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hammmatt
This seems awesome. They neglect to mention how to power any circuits and what
components you could and how. If this could be perfected though, Electrical
Engineers would slowly take over the world... with circuits....

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andrewflnr
They already did.

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hammmatt
:) It's nice to hear we are appreciated.

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andrewflnr
Great, now they just need to stock compatible napkins in bars. "hey, I've got
this idea... Look, it works!"

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NonEUCitizen
Always carry a few LEDs and resistors in your pocket!

