Re: [CAD_CAM_EDM_DRO] How to go from 2.5 D to real 3 D ??

tom.kay@... wrote:

> Hi All
>
> I am getting closer to running my 3 stepper motors for the first
> time, using Dan Mauch's 5 amp boards. Setting aside all the fine
> tuning etc, for the moment, I am most curious about cutting metal in
> real 3D using 3 steppers, or even a 4th axis (rotary table).
>
> I think I get the concept about what's 2.5 D and what's 3D. In 2.5 D,
> you do some x-y movements, then stop, lift the tool in the z axis,
> then stop, and do more x-y cutting. In 3D, all three axes can move at
> once. Or 4, if you have a rotary device.
>
> But how do you make the jump up to 3D? Right now, I can draw
> something in Corel Draw, save as a DXF file, convert to G-code, and
> away I go. My drawings are 2-D. I would REALLY prefer to stay with
> Corel Draw if I can (instead of AutoCad) but I'd like to try 3D. Do I
> have to draw differently, essentially a 3D drawing? Does anyone know
> if this can be done in Corel Draw?

I seriously doubt you can do this with corel draw. You don't have to
use AutoCad, there are loads of alternatives. I use Bobcad/CAM.
It has a somewhat quirky way of constructing 3-D objects, but it
can do it. There are other programs that can accept 3-D data in
DXF format (Bobcad does, in fact) but I doubt Corel Draw can do them.

> I am planning on buying Art's Master5, since I hate DOS, and it seems
> to operate smoothly, according to feedback about the software.
>
> Also, how does the G-code get generated for a real 3D operation? Are
> the files typically huge compared to 2D work?

Not necessarily. If you force it to remove huge amounts of metal with
tiny tools, then the files can become large. If you only remove a little
material with appropriatly sized tools, the files are not large at all.

Designing 3-D solids and then machining them on a 4-axis system
is not doable on any of the very low-cost systems like Bobcad/CAM.

Jon