Date: Mon, 9 Jul 2012 12:34:40 -0400
Reply-To: David Beierl <dbeierl@ATTGLOBAL.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: David Beierl <dbeierl@ATTGLOBAL.NET>
Subject: Re: printing parts
In-Reply-To: <20120709104426.151NK.460711.imail@eastrmwml302>
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At 10:44 AM 7/9/2012, Dave Mcneely wrote:
>Actually, stuff I've read states explicitly that the process can
>print with metal alloys, plastics, other materials. But, what do I
>know? mcneely
There are many different processes, with wildly differing startup and
processing costs, materials, and results. The article that Scott
pointed to http://en.wikipedia.org/wiki/3D_Printer gives a good
beginning overview of the various techniques and applicable
materials, and you can search YouTube for videos of the different
techniques. Be aware that there's a video out there from NatGeo
showing the scanning and reproduction (in plaster) of a "Crescent"
wrench that is quite misleading as to details, and I'm ashamed of the
National Geographic Foundation.* They don't mention it in the video,
but the speed of that particular inkjet-type prototyping machine is
IIRC about one inch of depth per hour. But you can also see laser
sintering, drop deposition and other techniques. I think the
industrial machines probably start well upwards of $50k and go way up
from there; the hobby machines are under a grand or so but as far as
I know are limited to drop-deposition techniques which makes them
both crude and limited to things that melt at low temperatures.
*I also object to the probably unconsciously aggressive behavior of
the NatGeo "scientist" guy with the large wrench, who spends a lot of
time (seconds!) gently tapping his palm with the big end of it. I
imagine it only means that the only time he's seen such a wrench
before has been in a violent movie...
Martin's eos laser-sintering machine (tree starts at
http://www.eos.info/en/products/systems-equipment.html ) can
certainly make pistons if eos supply a suitable alloy powder for
it. And they do have an aluminum/silicon/magnesium alloy that might
be great. At present they'd be darn expensive pistons,
though. Volkswagen have already used it to make what must be the
ugliest (YMMV) shifter knob in known space from stainless steel, see
http://www.eos.info/en/applications/automotive/project-volkswagen.html
Martin, any idea what your lab would sell a thermostat housing for in
AlSi10Mg alloy? Or CoCr SP2 for that matter? Call it three ounces
of aluminum as a wild guess? And how long would it take to make one
given an original? Actual processing time, I mean. I'm guessing you
normally build the wax on the plaster articulation model, then scan
it, am I close? In that case assuming your machine is big enough,
you could start with the scan. Also, do you have a clue what the
eos setup cost?
The baby is just learning to crawl...it's reached the point of being
useful for luxury one-offs, expensive custom parts, medical implants,
aerospace components, other cost-no-object items or ones where
tooling would be very expensive and/or mechanical qualities aren't
very important. It's been used for a while for making prototype
models from plaster, like Detroit's clay cars in small (up to
milk-crate size, I think), and for polymers. Solid metals are newer.
I don't think (be nice if I'm wrong) it's going to be a lot of help
to your average Vanagonaut for a few years yet.
Science-fiction people might take a look at Neal Stephenson's _The
Diamond Age_. for some thoughts about where this could go. I reckon
you'll either love it or hate it - the book, that is. Stephenson is
many things. Concise is not one of them.
Yours,
David
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