
Engineer creates a 3D metal printer prototype for $2 using electroplating - praptak
http://www.3ders.org/articles/20150301-low-cost-metal-3d-printing-made-possible-with-electroplating-technology-and-prototype.html
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dragontamer
> It is a 3-axis CNC machine combined with an electroplating head.

Erm... CNC Machines can cost thousands of dollars. I think this guy made a $2
attachment to a CNC Machine that then spits out copper.

Which is cool and all, but the headline doesn't seem right to me.

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tinco
Yes, and the very first picture shows that amongst the additions is an HP lab
power supply worth well over $200 second hand.

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vanderZwan
> high amount of energy required to 3D print a metal object

I'm very curious how the energy efficiency compares to other methods of
production. After reading this[0] article I've become highly suspicious of how
easily the energy footprint seems to be overlooked in maker cultures.

[0] [http://www.lowtechmagazine.com/2014/03/how-sustainable-is-
di...](http://www.lowtechmagazine.com/2014/03/how-sustainable-is-digital-
fabrication.html)

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koala_man
>That’s right, just $2. No zeros in sight!

Hmm, let me see if I can find those zeroes...

>his 3D metal printers could be sold for between $1,000 to $2,000

There they are!

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InclinedPlane
Which seems to be the universal price range for entry level 3d printers.

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woah
How long does it take?

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marcosdumay
Let's see.

Copper has valence 1, that means that one atom is deposed by each election
that flows on the system. A mol of copper has 63g, thus, for each 100,000C
that flows, there'll be 63g deposed. The video says it uses 100mA of power,
what makes it capable of deposing 63µg/s at most.

Serious galvanoplasty power supplies start at the 50A mark for a reason.

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tonyarkles
Doing a bit of in-my-head math... At 1A, that'd be about 50g/day.

I don't remember the voltage required for electroplating using CuSO4+acid, but
I remember it being low. I suppose it probably has to do with electrode
spacing too. As a guesstimate, let's go for 5 volts (which I have no idea of
the accuracy).

If we're stepping household 120V down to 5V, we've got a factor of 60
reduction. With a (big ass) buck converter, we can in theory get 15A*60 = 900A
= 900C/s out of a standard breaker. That works out to 49kg/day? That seems
ridiculously large. I'd love for someone to point out what I did wrong though.
I've assumed 100% efficiency everywhere, but even cutting it down to 10% still
results in ~5kg/day.

Edit: I'm sure it's an expensive power supply, but it's nice to see that I got
in the right ballpark: [http://www.americanplatingpower.com/reverse-pulse-
power-axd-...](http://www.americanplatingpower.com/reverse-pulse-power-axd-
compact-s.php)

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mschuster91
> With a (big ass) buck converter, we can in theory get 15A*60 = 900A = 900C/s
> out of a standard breaker

No way you're gonna run 900A through this little pencil - the temperatures at
contact point will act like a welding machine (uncontrollably
melt/vaporize)...

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Turing_Machine
Indeed. You can probably run a lot more than normal if you keep the tip
submerged and circulate the electrolyte, but you're not gonna run 900 amps
through it.

Some useful equations and numbers here:

[http://www.ami.ac.uk/courses/topics/0223_plate/index.html](http://www.ami.ac.uk/courses/topics/0223_plate/index.html)

