Re: cad to gcode and arcs

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Chris Brick" <cbrick@t...>
wrote:

> I got my plasma table up and running last night.
>
> I've been testing out some of the CAD/CAM packages for generating

gcode for letters and

> other intricate shapes.


> My question is, are there any packages that can do this conversion

to arc/circle from

> autocad or other drawings and which one would you recommend?
> Thanks,

Chris, Vector cam will directly import any arcs in DXF files, UNLESS
you have used the bulge type of entity. These may be problematic in
just about any cad-Cam system, depending on the age of the release
you are using. AutoDesk keeps changing the DXF (and Dwg) format to
attempt to retain competitive advantage. If you use a bezier or
similar curve type, the Vector 3D surfacing option will automatically
convert these splines to Nurbs curves.

If you have a cubic spline or even a Nurbs curve, converting it to G-
code will result in a series of interpolated linear G01 moves. The
splines ar enot directly supported in G-code. Vector has a
simplification function that fits arcs (within an arc-chordal
tolerance you set) to the curves.

Either way you end up with simplified G-code.

Next question, what kind of controller software are you using that
cannot cut a series of lines or a combination of arcs and lines with
equal ease? Most of the controller designers have been beat up so
bad over the last 2 or 3 years that most have stepped up to the plate
and implemented some kind of Continuous contouring or similar
trajectory planning that the drawing entity form does not affect the
cutting capability.

Fred Smith - IMService

Freshly back from the CNC area at NAMES Can you say YAHOO?