Re: [CAD_CAM_EDM_DRO] Re: Profiling circle errors

> You guys are right, its generating linear moves. I changed the
> parameter in visualmill, same thing though. I will take this over to
> them and see what they say.

Hi,

In VisualMill there are at least two settings which affect circle output.
First, the setting in Preferences->Machining->Output arcs as linear segments
has to do with how the arc moves are generated.

Second, in the MOps, is a relation between the chord tolerance under the Cut
Parameters tab and the 'Cut Arc Fitting' under the Advanced Cut Parameters
tab. The chord tolerance should be less than the arc-fit tolerance for good
results. This primarily affects toolpaths from splines or 3D models.

For imported 3D models, the part faceting tolerance under
Preferences->Tolerances should be set to a value that fits the chord
tolerances you need.

Keep in mind that G02/G03 require flat arcs in a cartesian plane. If the
circle you drew is not flat (planar in the XY, YZ, XZ, or machining
coordinate system), G02/G03 output won't work. You can check for this by
looking at the g-code output for differing Z levels among the profile moves.

Have you tried a simple G02/G03 circle move from the operator interface of
Mach 2? That would help clarify whether your machine setup is giving you
problems, or soley a CAM issue. To my understanding, Mach 2 makes no use of
encoders for its' control loop. Hence that should have no effect.

The following code does a .500 radius circle clockwise, then
counter-clockwise, around a center of x0,y0. (in half circle segments)

N10 G00 X0.500 Y0.000
N20 G02 X-0.500 Y0.000 I-0.500 F15
N30 G02 X0.500 Y0.000 I0.500
N40 G03 X-0.500 Y0.000 I-0.500
N50 G03 X0.500 Y0.000 I0.500

HTH,

Keith