On Wed, 29 Apr 2015 09:33:39 -0400, Leon Fisk
wrote:
On Tue, 28 Apr 2015 21:21:56 -0500
Martin Eastburn wrote:
snip
Artificial arms, legs are being made with 3-D printers. It is dropping
the cost for more to have them.
A local article ran in our paper about this late last year:
http://www.mlive.com/news/grand-rapi...oler_gets.html
"CEDAR SPRING, MI - The robotics team from West Catholic High School
gave a 4-year-old Cedar Trails Elementary student the right hand she
never had on Thursday, Dec. 19.
"I'm going to paint them (nails) pink," said Harmony Taylor with a big
smile as she pulled on each finger of her customized Robohand and
strolled around the school media center, getting a feel for the device
and using it.
Using it, she easily picked up the gift bag from the West Catholic
students who made the device. It included a bottle of pink nail
polish..."
According to a government source, there were over 12,000 articles
published about AM/3D printing a few years ago. The number now is
higher. The general press has gone ga-ga over it.
Thus, some people are "disappointed" that it hasn't revolutionized
manufacturing. But the only people who would feel that way are people
who have no understanding of manufacturing technology. I didn't read
the original post in this thread so I don't know who is saying they're
"disappointed," but the only people to whom that applies are people
who don't know how things are made -- or people who let themselves get
sucked in by the gushy articles in the general press.
For the rest of us, it's pretty damned exciting, because it's not hard
to see where the low-hanging fruit is for AM. George pointed to a
number of things -- prototypes, casting patterns, and so on. I wrote
an article recently about Volvo Trucks making their production tools
out of 3D-printed ABS plastic. Custom prostheses, in both plastics and
metals (ceramics are coming soon, too), like your example, are being
made right now. It's revolutionizing prosthetic dentistry.
Where it gets really interesting for us is in the new AM processes for
metals. This is a story that's evolving from month to month. There are
several production applications in daily use, including the
often-cited example of fuel nozzles for aircraft turbines. These are
parts that can't be machined in one piece, and the traditional
multi-part assemblies are a sore spot for the manufacturers. With AM,
they make the whole thing as a single part. This suggests something
like what happened when EDM got involved in making aircraft parts.
They wanted deep,square holes. EDM gave it to them. They wanted lots
of other odd geometry. More EDM.
So the first metal AM applications are likely to be for things that
are difficult or impossible to machine. I wrote a piece on metals for
AM this month, and there is a perfect example illustrated in the
article. Take a look at this injection mold:
http://www.nxtbook.com/nxtbooks/fabs.../index.php#/18
Those cooling passages are built right in. They result in a mold that
can cycle 40% faster. So it's 40% more productive than a conventional,
machined mold.
There are a lot of other tooling applications coming along, and not
just for difficult-to-machine parts. Some of them are just for custom
tooling that you need this week, rather than two or three months from
now.
The limitations are several. A big one, right now, is the types of
metal that can be 3D printed. That injection mold is made of maraging
steel -- an odd choice for a mold, one might think, but it's explained
in the aricle.
What I'm watching for now is an evolution that will allow AM of D2,
A1, H13, and other tool steels. I don't think it will be long in
coming, based on what the manufacturers are saying. And companies like
NanoSteel and Oerlikon are developing special powders for AM that may
not be the same as traditional tool steels, but which give similar or
better performance.
So how one looks at AM depends on what one knows about existing
processes. It's exciting for those who know. It may be disappointing
for those who don't.
--
Ed Huntress