On Sat, 6 Jul 2013 20:23:12 +0000 Chris Morley <chrisinnana...@hotmail.com> wrote:
> I guess it really comes down to at what performance machine does jerk > limitation show real benefits ? I would guess that almost all machines _we_ deal with would benefit from jerk limiting. A machine that might be able to get away without limiting jerk would be something where the moving parts had very little mass, like maybe a tiny plotter or a tiny gimbal. > And I still don't see why one would want to turn off jerk limiting > for some machine movements. Here's what I think Jon is talking about: When in a rigid tapping cycle, the Z axis is "slaved" to the rotational position of the spindle. The spindle will have its own characteristics of motion, but we don't always have tight servo control over them. For example, at the bottom of a tapped hole, the spindle must reverse, but it may come to a stop with a jerk due to high friction (you've probably experienced a tapping operation where the tap wants to move in small jerks rather than smoothly cutting). At this point the Z axis should probably be controlled with no limit on jerk (and maybe no acceleration limit either) so as to maintain the spindle-to-Z-axis position relationship which is critical since they are now _mechanically_ interlocked through the tap and it's threads in the workpiece. > Interesting discussion. Yes! Thanks, Matt ------------------------------------------------------------------------------ This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
