In article ,
says...

Some time ago, there was a TV special about the re-encasement of the
Declaration of Independence, Constitution, and Bill of Rights.
It included a short clip of an amazing milling machine, whose head was
suspended over the workpiece on a set of what looks like hydraulic
rams. Since then, I've been trying to find more information about
this machine, and it's capabilities.

I finally found a small picture of it, and bumped it's size up 300%:
http://webpages.charter.net/dwarner2/MillingMachine.jpg

Does anyone have an idea who makes it?


Looks like it could be a hexapod. I believe Ingersoll was
working on this concept. I don't know if anything practical
has come of it yet.

Ned Simmons

Doug Warner wrote:

Some time ago, there was a TV special about the re-encasement of the
Declaration of Independence, Constitution, and Bill of Rights.
It included a short clip of an amazing milling machine, whose head was
suspended over the workpiece on a set of what looks like hydraulic
rams. Since then, I've been trying to find more information about
this machine, and it's capabilities.

I finally found a small picture of it, and bumped it's size up 300%:
http://webpages.charter.net/dwarner2/MillingMachine.jpg

Does anyone have an idea who makes it?

Some time ago, there was an article in Model Engineer about a machine
like that. The name "hexapod" comes to mind, though I don't know if
that was the ME machine or not. Anyway, if you google hexapod you get
about 62K hits, with http://www.hexapods.net/hexapod.htm being on top.
They show a platform controlled by six hydraulic cylinders, and if you
look at your picture, it looks like it could be the same arrangement.
For a quick look, see http://www.physikinstrumente.com/images/HexAnim6.gif.

A search for hexapod milling machine would find better info, I expect,
but that could get interesting enough to take the rest of the evening.

HTH,
Tove

As others have suggested, you saw a "hexapod". You can also search for
"parallel kinematic mechanisms" for (typically) more technical info.

I saw an Okuma PKM at a machinery show a couple of years ago. I actually got
to hang off the head (as a demonstration of its rigidity). The head was
indeed solid. The feeling was similar to haging off a rock face - absolutly
no movement.

Neat machine, and theory. See:

http://www.sme.org/cgi-bin/get-mag.p...005&ARTME&SME&

Regards,

Robin

"Doug Warner" wrote in message
...

Some time ago, there was a TV special about the re-encasement of the

Doug Warner wrote:
Some time ago, there was a TV special about the re-encasement of the
Declaration of Independence, Constitution, and Bill of Rights.
It included a short clip of an amazing milling machine, whose head was
suspended over the workpiece on a set of what looks like hydraulic
rams. Since then, I've been trying to find more information about
this machine, and it's capabilities.

I finally found a small picture of it, and bumped it's size up 300%:
http://webpages.charter.net/dwarner2/MillingMachine.jpg

Does anyone have an idea who makes it?

A page describing the building of the cases:
http://www.nist.gov/public_affairs/C...ncasements.htm
Yup, this was the Ingersoll hexapod (Stewart platform) machine
that was at the NIST machine shop for a few years. I missed seeing
it there when I recently visited the NIST shop, as it is out on loan to
another facility right now. There may be some more info at a NIST
web site somewhere, probably in the IMD or MEL pages. Try
http://www.mel.nist.gov/melhome.html

and here's an overall picture :
http://www.mel.nist.gov/galleryph/in...s/hexapod1.htm

Jon

"Doug Warner" wrote in message
...
I finally found a small picture of it, and bumped it's size up 300%:
http://webpages.charter.net/dwarner2/MillingMachine.jpg

Does anyone have an idea who makes it?

http://www.prsco.com/

--

SVL

Doug Warner wrote in
:

Some time ago, there was a TV special about the re-encasement of the
Declaration of Independence, Constitution, and Bill of Rights.
It included a short clip of an amazing milling machine, whose head was
suspended over the workpiece on a set of what looks like hydraulic
rams. Since then, I've been trying to find more information about
this machine, and it's capabilities.

I finally found a small picture of it, and bumped it's size up 300%:
http://webpages.charter.net/dwarner2/MillingMachine.jpg

Does anyone have an idea who makes it?

A page describing the building of the cases:
http://www.nist.gov/public_affairs/C...ncasements.htm

As others have said it's a hexapod. Actually it's an octahedral hexapod.
If you type that into Google you'll get a lot of hits and info. While the
kinematics and stiffness of the machine are interesting, the design
completly ignores Abbe's principal of measurement, which is fundamental
in machine tool design. The net result is that hexapods are not very
accurate, and AFAIK no builder has come up with a solution.

Honda Engineering built a horizontal machining center that used some of
the concepts of a hexapod design. I saw it at the JIMTOF show in Japan.
It has an M shaped frame with the spindle in the "V" in the middle of the
"M". The machine was absurdly fast and mezmerising to watch.

The machine is hard to describe, so here's a link.
http://www.mmsonline.com/articles/019905.html

Scroll down to the bottom of the page. It's one of the fastest machines
I've ever seen.

One of the advantages this machine has over a linear servo motor type
machine is that this thing had plenty of power. But again, since the
reference scales don't coincide with the axes, it's probably not very
accurate without a lot of mapping. It would probably make one hell of a
router though.

Here is a link to a site that discusses these and other machines and
robots with this type of design. http://www.parallemic.org/


--

Dan