On 07/21/2020 12:00 PM, Robert Ellenberg wrote:
Based on the videos and your descriptions of the behavior, you may be
running into a TP issue I've seen (in simulation) with very sluggish
spindles or very high spindle speeds. Here's what I think is going on:
1. The rigid tapping cycle allows a hard-coded 10 revolutions
<https://github.com/LinuxCNC/linuxcnc/blob/master/src/emc/tp/tc.c#L856>
of overtravel beyond the nominal bottom of the hole when reversing
direction.
2. The spindle starts reversing direction only after the Z axis has
reached the bottom, so the spindle has to be able to stop in 10 revolutions
to stay within the budgeted overtravel.
3. If the TP hits the end of the overtravel, it prematurely declares the
motion to be complete and stops following the spindle motion.
AND, so the guy who actually WROTE THE CODE explains what is
REALLY going on!
Yes, that explains at least the first video quite well.
Obviously, for rigid tapping, you need a spindle drive that
is capable of a pretty strong stop and reversal.
Jon
_______________________________________________
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users
