How does Mach Ramp?

[ssutton]

I have noticed over the course of time that my machine has a tendency to jerk, or maybe better said a lack of smoothness. I never seem to lose steps and the machine works fantastic when just cutting along, BUT, when i am cutting something with lots of tiny little lines like an arc that has been broken up into lots of tiny strait lines I begin to see the gantry become unstable and a noticeable amount of bounce becomes apparent.

I just noticed today that when I am approaching a soft limit and Mach begins to ramp down that the same exact bounce begins to occur. This makes me think that when Mach is accelerating or decelerating that it does it in discrete steps and not a linear ramp. If this is the case, can I change a setting that defines the amount of the step?

Thanks to all, without this group I would have never been able to have my machine running at all!

Scott

[RICH]

Scott,
You can work in exact stop or constant velocity ( CV).
Try the CV mode and you will see a difference in the machines smoothness.
Have a read about CV mode as there are some settings that come into play to avoid rounding of corners.

RICH

[Picengraver]

Scott,
Are you using micro-stepping?  Sounds like maybe your steppers may be getting into a resonant velocity range as they slow down.

Regards,
John Champlain