Re: How to go from 2.5 D to real 3 D ??

Fred,

Let me get a little nit-picky here with definitions.

I see a significant distinction in terminology between DOING 3D
machining and a machine being RATED as having 3D capability.

A machine capable only of simultaneous 3 axis LINEAR moves can DO 3D
machining by creating the surface with short line segment moves.
That machine would be considered a 2.5D machine since it can only do
the 3 axis simultaneous moves as LINEAR. Even though it can cut
surfaces that would be considered 3D.

A machine RATED as 3D has to do circular interpolation with
simultaneous moves in all 3 axii. Quite a difference from just DOING
3D machining. (Helical interpolation, by itself, doesn't qualify a
machine as 3D since that's a special case).

That's the way it's been explained to me by machine tool salesmen.
Are these the current machine tool definitions?

Here's an example of how confusing the definitions can get. A few
years back, a customer of mine ordered three of the small Bridgeport
vertical CNC mills. The quotation from the dealer's salesman listed
them as 3D machines. After they were installed, it turned out they
would not do circular interpolation using the Z axis, only in X & Y.
Lawyer time!! I know the dealer made some sort of settlement to the
customer for misrepesenting the machines.


thanks,

Doug

--- In CAD_CAM_EDM_DRO@y..., "IMService" <imserv@v...> wrote:

(snip)

>
> The predominant application of 3 axis machining is for surfacing
molds and prototype parts, probably followed next by 3D sign making.
The basis of 3D machining is the ability to make 3 axis simultaneous
moves and it is absolutely not in any way related to whether or not
the machine is cutting arcs or lines. Most 3D surfacing is done with
huge files consisting of point to point moves that have been
compensated for the desired surface and the geometry of the tool that
will be used.
>
>
(snip)