On 28 August 2011 16:00, Brian May <bri...@do-precision.com> wrote: > I would like to add a C-Axis. (I already > have it built and attached). Basically, when wanting to do live tooling > work, the C-Axis stepper motor engages on the spindle driving the spindle > instead of the spindle motor. When the lathe is turning parts the C-Axis > motor disengages. There is an encoder attached to the spindle so I can keep > track of its location.
With a good enough spindle drive you might not actually need the stepper. I did an experiment with a very old VFD and a conventional 3-phase motor and it nearly worked. I think with a modern flux-vector drive it might work properly. What is the minimum spindle speed your drive supports? (what type of drive is it?) If your drive is capable of zero-speed torque then it just becomes a case of unhooking the spindle speed command from motion.spindle-speed and re-connecting it to the output of a C-axis PID control. This is all reasonably easy in HAL. (you probably need an M-code to switch modes) -- atp "Torque wrenches are for the obedience of fools and the guidance of wise men" ------------------------------------------------------------------------------ EMC VNX: the world's simplest storage, starting under $10K The only unified storage solution that offers unified management Up to 160% more powerful than alternatives and 25% more efficient. Guaranteed. http://p.sf.net/sfu/emc-vnx-dev2dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
