Re: [CAD_CAM_EDM_DRO] Digitizing arm

Exactly how the presidents were carved in the black hills only they used a
beam that pivoted on a point above and in back of the head for the X axis.

Hugh

----- Original Message -----
From: Rick Dulas <drspiff@...>
To: <CAD_CAM_EDM_DRO@egroups.com>
Sent: Tuesday, November 14, 2000 9:58 PM
Subject: Re: [CAD_CAM_EDM_DRO] Digitizing arm


> Howdy! This is an idea I've been fascinated with for a long time, but I
keep running up against the problem of tip offset. Somehow
> you have to keep the normal to the surface at all times, but it is soluble
since somebody is making money at it. <G> At the
> Auburn-Cord-Dusenburg Museum in Auburn Indiana, they have the clay model
that was used for the 812 Cord. While I could rhapsodize
> about the car, the method they used to loft the prints was way too cool.
>
> Picture a gantry on parallel tracks aligned with the long axis of the car.
The X is the movement along these tracks. The Y is the
> travel along the bridge of the gantry and the Z is a rod that is dropped
from the Y cradle down to the surface of the clay model.
> Very much like the CNC router that someone on the list has. It was
accurate enough in the 30's to go from a 1/12th scale clay model
> to full size plans with no mockup in between.
>
> How's that for agile manufacturing? <G> On a relatively small scale you
could use the guts out of a wide carriage dot matrix printer
> for the X & Y and a servo/encoder in the Z to drive some sort of sensor up
and down to sense the surface. Maybe an IR
> transmitter/receiver in relective mode, or a phonograph cartridge/needle,
or...
>
> Rick Dulas
>
> richard_damian@... wrote:
>
> > Anyone out there built a 3D digitizing arm? That is a 3-axis arm with
> > stylus that is used to trace a 3D object and supply coordinates in
3-space
> > for creating a Cad model. I have an old profile mill in my shop that
does
> > a similar thing - it mechanically feeds a milling head by tracing a 3D
> > shape.
> >
> > Just wondering, people are paying big bucks in Cad magazines for what
> > appears to be a couple of metal arms, 3 encoders, a sylus and some
> > software....
> >
> > Dick
> >
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>
> Welcome to CAD_CAM_EDM_DRO@...,an unmoderated list for the
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