Mimi Patrick on wed 16 apr 08
Recently I had to have a crown done and it turned out to be a fascinating
process. First, the dentist took a digital picture of the tooth to be
crowned. That image was sent to a computer where he manipulated the image
with a three dimensional modeling program until he was satisfied with the
surfaces. Next a porcelain blank was loaded into another machine and the
new image was then sent to it. This machine has little diamond burrs on
robotic arms that come out and shapes the blank to match the image of the
crown. Water keeps the porcelain cool and the shaping process is completed
in about 4 minutes. The newly sculpted crown then goes into a very small
kiln after being coated with glaze. Firing takes about 20 minutes. One
hour later, the whole thing was done and I was on my way. Now that is
technology! I keep trying to visualize a carving machine like this on a
grand scale.
Mimi Patrick
Argenta Earth & Fire Co.
Snail Scott on thu 17 apr 08
:
> Date: Wed, 16 Apr 2008 06:55:49 -0700
> From: Mimi Patrick
> ...This machine has little diamond burrs on
> robotic arms that come out and shapes the blank to match the image of
> the
> crown... I keep trying to visualize a carving machine like this on a
> grand scale...
They do indeed exist. and are now being used to
do stone sculpture, sometimes from laser-scanned
3-D maquettes, and sometimes from purely digital
designs. The 'Digital Stone Project' in New Jersey
is one of the outfits that does this. It's basically a
five-axis milling machine. The grinding heads are
generally used to rough out the form to the basic
shape, but humans usually still do the final finishing.
Humans also have to take care of the undercuts
that didn't show in the laser scan or which the
cutting heads couldn't reach, Small details are
generally done by hand, too, when the size of the
detail is smaller than the big cutting heads. That
could also be done mechanically, I suppose, using
smaller cutters and a higher-resolution scan, but
the cost would probably escalate hugely.
-Snail
pdp1@EARTHLINK.NET on thu 17 apr 08
Hi Snail, all...
The Dies for our present abysmal and increasingly ridiculous looking coinage
are made by those means, while also going through several stages of
reduction from a bad and physically absurdly large design exemplar ( like a
'dinner plate' in size, if not a 'garbage can lid' in size ) , to a final
grotesque realization-result in actual size of the gruesome coin itself.
Apparently - design aesthetics aside - the execution is felt to be less
expensive or more satisfying to the pathology of bureaucracy than does
employing an actual able Engraver ( person ) to simply made the Dies
directly in their actual size, engraved the 'master' Dies directly, as had
been the method previously when our Coinage had been suburb.
Higher resolution scans, and smaller Tooling bits I do not believe cost any
different to utilize than the large clumsy 'roughing' ones. The expense is
merely for the Computerized Machine itself, and scales of detail in
operation or Tooling
options are merely what the Machine does according to it's programming
mode...far as I recall...
I have an old Book here somewhere 1912 I think, which is a survey of all the
design Prototypes for Coins, which had submitted to Congress for approval,
but which
were not approved, from I think 1784 to 1910. While the Coins which were
approved and Minted were of course very well done and lovely during that
period , the ones not-elected ( during the
period the Book covers, ) were also really excellent and interesting and
generally quite lovely, if different of course than what was done, in one
way or another.
So now, with all this sophisticated technology, we see an absurd sequence of
tedious successive reductions of truly bad and stupid in-every-way designs,
culminating
in a crude, 'play money' looking product full of round-bottom lines and poor
'shelf' kinds of relief and sodden if not crude attempts at 'referencing no
longer present detail...where, for so long, real,
actual serious, able Engravers created the Dies 'by hand' with truly superb
results in every aspect.
Oye...
Anyway...
"Crowns" indeed...
Phil
l v
----- Original Message -----
From: "Snail Scott"
> :
>
>> Date: Wed, 16 Apr 2008 06:55:49 -0700
>> From: Mimi Patrick
>> ...This machine has little diamond burrs on
>> robotic arms that come out and shapes the blank to match the image of
>> the
>> crown... I keep trying to visualize a carving machine like this on a
>> grand scale...
>
>
> They do indeed exist. and are now being used to
> do stone sculpture, sometimes from laser-scanned
> 3-D maquettes, and sometimes from purely digital
> designs. The 'Digital Stone Project' in New Jersey
> is one of the outfits that does this. It's basically a
> five-axis milling machine. The grinding heads are
> generally used to rough out the form to the basic
> shape, but humans usually still do the final finishing.
> Humans also have to take care of the undercuts
> that didn't show in the laser scan or which the
> cutting heads couldn't reach, Small details are
> generally done by hand, too, when the size of the
> detail is smaller than the big cutting heads. That
> could also be done mechanically, I suppose, using
> smaller cutters and a higher-resolution scan, but
> the cost would probably escalate hugely.
>
> -Snail
Carl Finch on thu 17 apr 08
At 06:55 AM 4/16/2008, Mimi Patrick wrote:
>Recently I had to have a crown done and it turned out to be a fascinating
>process. First, the dentist took a digital picture of the tooth to be
>crowned. That image was sent to a computer where he manipulated the image
>with a three dimensional modeling program until he was satisfied with the
>surfaces. Next a porcelain blank was loaded into another machine and the
>new image was then sent to it. This machine has little diamond burrs on
>robotic arms that come out and shapes the blank to match the image of the
>crown. Water keeps the porcelain cool and the shaping process is completed
>in about 4 minutes. The newly sculpted crown then goes into a very small
>kiln after being coated with glaze. Firing takes about 20 minutes. One
>hour later, the whole thing was done and I was on my way. Now that is
>technology! I keep trying to visualize a carving machine like this on a
>grand scale.
Such machines "on a grand scale" have been around for over half a century!
They're called Numerically Controlled Machine Tools,
or simply NC.
What's new is the machine you describe, a micro, mini, scaled-down version
of the originals! Those originals were created=20
to machine single pieces of metal
the size of airplane wings. Actually, they *were* for airplane wings.
In order to get smooth machined surfaces it was necessary to control more=
than
just three axes (x, y, and z), and so additional=20
rotational control of the cutting head
was added (4- or 5-axis control). This also allowed undercutting.
As you might imagine, in these early days (computer-wise) programming was
a huge job--calculating all those thousands of tiny moves of milling cutters
through three dimensions, and maintaining a flat-ended cutter perpendicular
to the desired wing surface (so as not to leave a "scalloped" finish).
Eventually computer languages were created to describe the shapes and=
motions
required to describe the shape desired and the=20
cutter paths needed to machine it.
People who used these languages were, first of=20
all, highly skilled machinists and
were called "parts programmers."
With the advent of fast computers and computer graphics and the=
miniaturization
of the machine tools themselves, the manual parts programming can be=
eliminated
or at least reduced, so that--voil=E0--even your=20
dentist can manufacture your crown!
--Carl
in Medford, Oregon,
who hasn't had to pick spiral chips
of metal out of his soles for decades=20
Bobbie Fenton on thu 17 apr 08
Already is such an animal - but it reproduces copies in wood. Will copy anything then copies it in wood - really neat machine. Don't know if there's anything that does that in our craft yet.
Bobbie Fenton
Mimi Patrick wrote: Recently I had to have a crown done and it turned out to be a fascinating
process. First, the dentist took a digital picture of the tooth to be
crowned. That image was sent to a computer where he manipulated the image
with a three dimensional modeling program until he was satisfied with the
surfaces. Next a porcelain blank was loaded into another machine and the
new image was then sent to it. This machine has little diamond burrs on
robotic arms that come out and shapes the blank to match the image of the
crown. Water keeps the porcelain cool and the shaping process is completed
in about 4 minutes. The newly sculpted crown then goes into a very small
kiln after being coated with glaze. Firing takes about 20 minutes. One
hour later, the whole thing was done and I was on my way. Now that is
technology! I keep trying to visualize a carving machine like this on a
grand scale.
Mimi Patrick
Argenta Earth & Fire Co.
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