On Tue, 19 Jan 2021, Gene Heskett wrote:
It wasn't the last time I tested it Jon, and most of the recent conversations here are ignoreing the fact that every new stroke, starting from its resting position, regardless of whether its a G76 or you are "pecking" a G33.1 for rigid tapping, is a NEW sync action, and its here that diddling the the spindle speed affects both the accel time to get Z up to sync speed, so in addition to the spindle turning further at a higher speed, it also takes Z longer to get up to that higher speed and become phase locked. This combined change in the delay from 0 to locked is changing the phasing between the spindle and the tool at about 2x the change in spindle speed. And screwing up your thread.
As long as the sync can happen before the tool hits the metal that will be no error in the created thread (no phase error) regardless of when the speed change occurs. The only change will be where the thread starts. Once synced, this is basically identical to a mechanical lathe (when the half nut is engaged).
Peter Wallace Mesa Electronics _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
