--- In DynoMotion@yahoogroups.com, Tom Kerekes <tk@...> wrote:
>
> Hi Mike,
>
> That is interesting.  What was the feed rate you were using?   What was your "Look Ahead" time setting?
>
> I think what is happening is that the arcs are being broken down into smaller arcs that do not take too long to execute.  This allows the Trajectory Planner to work on only the next few seconds of motion in case something like the FRO changes.  Also small arcs are executed as line segments if this can be performed without exceeding the collinear tolerance.  This allows microscopic arcs and line segments to be combined and formed into a smooth path.
>
> I did the math and a 6 inch diameter circle can be made with a 172 sided polygon where each side is 0.219 inches long without exceeding a 0.001 inch tolerance.  The "facets" have ~2 degree angles which might get "rounded" to form 1 degree angles.
>
> If you set the collinear tolerance to zero you are telling the Trajectory Planner that it must follow the GCode path exactly.  Which means that if there is a 1 micro inch square corner or zig-zag some place then the tool must come to an exact stop to perform that motion perfectly.  So you might observe what appears to be a jerky pause in what appears to be a smooth path.  Many CAD systems do such things due to numerical rounding.
>
> I would just reduce the Collinear Tolerance and Corner rounding to 0.0001.  Also maybe a facet angle of 0.25.  (zero is not a good idea here because that requires an infinite number of sides to make an angle).
>
>
> HTH
> Regards
> TK
>
>
> ________________________________
> From: michaelthomasn <michaelniksch@...>
> To: DynoMotion@yahoogroups.com
> Sent: Saturday, February 23, 2013 7:22 AM
> Subject: [DynoMotion] Trajectory Planner Settings
>
>
>  
> Hi Tom,
>
> I'm getting to use my mill a bit more lately, and I must say I'm very pleased with Kflop/SnapAmp Performance.
>
> I made a round piece yesterday that is 5.920 inches in diameter....but noticed it is faceted. It has roughly 290 facets. The part came out beautifully, and the facets are not a real concern.....but my CAM program is using G2/G3 arcs so I wasn't expecting to see any faceting.
>
> I read the tutorial about the corner rounding and facet angle, but it seems to be geared toward dealing with CAM that is outputting line segments instead of arcs.
>
> My trajectory planner settings are:
>
> Break Angle 10
> Collinear Tolerance .001
> Corner Rounding .003
> Facet Angle 1
>
> This is a pretty low speed machine that will always have G2/G3 arc code to use. What changes could I make to my above settings to remove the faceting on arcs?
>
> I'm suspecting I should change my facet angle and corner rounding to 0.....and maybe the collinear tolerance to a smaller number as well.
>
> My CAM system is Featurecam, and it has always seemed to be pretty smooth output on other mills I have used compared to other CAM systems....probably because of the arc feature.
>
> Mike
>

--- In DynoMotion@yahoogroups.com, "michaelthomasn" <michaelniksch@...> wrote:
>
> Tom,
>
> My feedrate was a brisk 4 ipm on the finish pass.....lol.
>
> Look ahead is set at 3 seconds.
>
> Mike
>
> --- In DynoMotion@yahoogroups.com, Tom Kerekes <tk@> wrote:
> >
> > Hi Mike,
> >
> > That is interesting.  What was the feed rate you were using?   What was your "Look Ahead" time setting?
> >
> > I think what is happening is that the arcs are being broken down into smaller arcs that do not take too long to execute.  This allows the Trajectory Planner to work on only the next few seconds of motion in case something like the FRO changes.  Also small arcs are executed as line segments if this can be performed without exceeding the collinear tolerance.  This allows microscopic arcs and line segments to be combined and formed into a smooth path.
> >
> > I did the math and a 6 inch diameter circle can be made with a 172 sided polygon where each side is 0.219 inches long without exceeding a 0.001 inch tolerance.  The "facets" have ~2 degree angles which might get "rounded" to form 1 degree angles.
> >
> > If you set the collinear tolerance to zero you are telling the Trajectory Planner that it must follow the GCode path exactly.  Which means that if there is a 1 micro inch square corner or zig-zag some place then the tool must come to an exact stop to perform that motion perfectly.  So you might observe what appears to be a jerky pause in what appears to be a smooth path.  Many CAD systems do such things due to numerical rounding.
> >
> > I would just reduce the Collinear Tolerance and Corner rounding to 0.0001.  Also maybe a facet angle of 0.25.  (zero is not a good idea here because that requires an infinite number of sides to make an angle).
> >
> >
> > HTH
> > Regards
> > TK
> >
> >
> > ________________________________
> > From: michaelthomasn <michaelniksch@>
> > To: DynoMotion@yahoogroups.com
> > Sent: Saturday, February 23, 2013 7:22 AM
> > Subject: [DynoMotion] Trajectory Planner Settings
> >
> >
> >  
> > Hi Tom,
> >
> > I'm getting to use my mill a bit more lately, and I must say I'm very pleased with Kflop/SnapAmp Performance.
> >
> > I made a round piece yesterday that is 5.920 inches in diameter....but noticed it is faceted. It has roughly 290 facets. The part came out beautifully, and the facets are not a real concern.....but my CAM program is using G2/G3 arcs so I wasn't expecting to see any faceting.
> >
> > I read the tutorial about the corner rounding and facet angle, but it seems to be geared toward dealing with CAM that is outputting line segments instead of arcs.
> >
> > My trajectory planner settings are:
> >
> > Break Angle 10
> > Collinear Tolerance .001
> > Corner Rounding .003
> > Facet Angle 1
> >
> > This is a pretty low speed machine that will always have G2/G3 arc code to use. What changes could I make to my above settings to remove the faceting on arcs?
> >
> > I'm suspecting I should change my facet angle and corner rounding to 0.....and maybe the collinear tolerance to a smaller number as well.
> >
> > My CAM system is Featurecam, and it has always seemed to be pretty smooth output on other mills I have used compared to other CAM systems....probably because of the arc feature.
> >
> > Mike
> >
>