Thanks Chris…for both the information and one of the most apropos example of autocorrect I have ever seen.
"The spinach is turning in x-direction the carnage in z” I think this will be my new signature line ;-) -Tom > On Feb 7, 2018, at 2:35 PM, Chris Albertson <albertson.ch...@gmail.com> wrote: > > The G33 says to do a synchronized move. This is physically impossible. > The Z axis has some limit on it's ability to go from zero speed to the > commanded speed. So the controller is reducing the spindle speed so as to > match the ability of the z-axis motor. > > ALL multi-axis moves are this way. You see it best on a milling machine > where perhaps the z-axis is also the slowest. Say you are milling a 45 > degree ramp that climbs upward to the left. The X motor would have to slow > to match the max speed of the z motor. > > When a lathe cuts threads it is in real-life cutting a ramp. The spinach is > turning in x-direction the carnage in z. You can only cut as fast as the > slowest motor can move. And nether of the motors has infinite acceleration. > > On Tue, Jan 30, 2018 at 2:42 PM, <tom-...@bgp.nu> wrote: > >> We have CSS on and are threading with a G33 on our Emco lathe and we are >> seeing the spindle decelerating during the cut. Seems like the spindle >> speed should be fairly steady at a given X location during a G33 and what >> it seems like is that the spindle is still decelerating to speed while it’s >> in the cut rather than before the cut. >> >> We are rapid-ing (G0 in Z) out of the part at the center of the part (X=0) >> and so CSS spins the spindle up to full speed as I’d expect (*) but it >> appears that our spindle is still decelerating to speed as the next >> threading pass is happening. We read that G33 will wait for >> spindle-at-speed before looking for the index pulse. But our >> spindle-at-speed signal seems to be high during the full cycle once the >> spindle speeds up the first time. It seems like spindle-at-speed should go >> low after rapiding out of the part as it moves to it’s next X location and >> decelerates to it’s next speed at the cutting diameter. Or are we >> misunderstanding spindle-at-speed when CSS is in effect? >> >> >> (*) Is it normal that a G0 move also triggers CSS to spin up (or down)? >> Seems like the trajectory planner would know where the next cutting move is >> and not adjust the spindle speed until it needs to. In our case we are >> rapiding out of the part at X=0 and the spindle speeds up when it doesn’t >> really need to. >> >> -Tom >> >> >> ------------------------------------------------------------ >> ------------------ >> Check out the vibrant tech community on one of the world's most >> engaging tech sites, Slashdot.org! http://sdm.link/slashdot >> _______________________________________________ >> Emc-users mailing list >> Emc-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/emc-users >> > > > > -- > > Chris Albertson > Redondo Beach, California > ------------------------------------------------------------------------------ > Check out the vibrant tech community on one of the world's most > engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
