[HH] 3D printing

[markw at mohawksoft.com]

> Re: fragility: properly treated, both the MakerBot and the uPrint can make
> structurally useful things.  It's not steel, but it's pretty good - more
> so
> in compression than in tension, but there are many materials like that
> which are pretty widely used - concrete, for example.  I can stand on a
> 20mm x 20mm block printed on the MakerBot, and it won't break.  The
> strength of the output depends pretty directly on the care taken in
> calibration, however.  It took me several months to get mine
> well-calibrated, learning all the way.  Post-printing treatment of the
> parts can make them an order of magnitude or so stronger than they come
> out
> of the printer, as well.

Its not about that. What is the value proposition for device? Are other
forms of manufacture more cost effective? On the consumer level, would a
consumer ever recoup the cost of the unit?

>
> A CNC router is $130,000 or so; they're not novelties, and are often used
> to produce parts in the $50 range.

A CNC device is a perfect example. The CNC device takes cheap mild steel
and mills it to a precision part. The cost of the machine is amortized
over its life time and they (the CNC machine) last a long time.

The cost benefit analysis for a CNC device are a reduced cost of
manufacture of small batches of parts. Decreased engineering time (takes a
drawing and makes a usable part). Long time durable machinery. Steel needs
to be at between 2600 and 3000 degrees to pour. Everything in its path
needs to be able to handle that. A CNC machine mills the metal cold and
can be much cheaper than molds in lower volume.

The 3d printers to do not use "cheap" materials. They use expensive
plastic compounds when compared to commonly manufactured plastics. Plastic
is easier to mold than steel. Lower melting points and much less energy
needed to work with it.

There are similarities, I grant you, between these 3d printers and a CNC
machine, but they are completely different technologies with widely
different cost/value ratios. Steel is hard to work with and a CNC machine
reduces that cost. Plastic is cheaper and easier to manufacture, and the
3d printer (in its current form) can't provide any positive ROI.

> The CPU you're using probably cost less than $300, the machine used to
> make
> it cost more than $3 million.

Yes, and the computer I am using "pays for itself" because I do work on it
and I am paid for that work, more than the cost of the laptop. If you are
talking about "entertainment" that has a different cost/benefit model.

>
> Yes, expensive tools like that are hard to afford on your own.  If only
> there were some sort of organization you could join for $40 - $125 a month
> that had some of these expensive tools and kept acquiring more.  ;-)

The value proposition is still not viable.
>
> The CNC aluminum router that can handle a 4'x8' sheet of 1" aluminum
> should
> be coming online in a month or two, depending on the electrician's
> schedule.  Then we build the 12' hydraulic hexapod robot.  (No, I'm not
> kidding.  With a saddle.)

Now, that sounds cool.
>
> *
> Drew Van Zandt
> Artisan's Asylum Craft Lead, Electronics & Robotics
> Cam # US2010035593 (M:Liam Hopkins R: Bastian Rotgeld)
> Domain Coordinator, MA-003-D.  Masquerade aVST
> *
>