On Saturday 07 July 2007, Jack Ensor wrote: >I have successfully upgraded an antique Bandit CNC on a Bridgeport to >EMC2. I am using the Axis user interface. > >Some of you may recall earlier postings of mine describing the >difference between the x and y dro readout on my Bridgeport versus the >emc2 readout that would occur when running the demo file, axis.ngc. The >difference varied from +0.0800 to -0.1000 (usually much less than these >extremes). > >I finally found out what was causing this error by writing a g code file >that oscillated the axis under test between + 8 inches and - 8 inches at >a feedrate of 5 ipm. I began at a feedrate of 100% and gradually >decreased it until I discovered an instability between 1.6 ipm (20 >stepper rpm) and 2.0 ipm (25 stepper rpm) due to stepper motor >resonance. I wondered how the original system handled these resonances >- maybe it was set up so that the firmware wouldn't let it operate at >these speeds. I was able to cure this problem by fabricating dampers >for the x and y axes. The z axis already had a damper on it from the >original Bandit system. > >Even though no one suggested that my problem could be due to stepper >motor resonance, I am ever grateful for the help that has been provided >to get me going. I couldn't have done with out it. Thanks! > >Now all error has been eliminated and I now have a system ready to cut >metal! > >Jack Ensor > Great, Jack. Now, when you get a chance, draw up or describe those dampers please. I'm not actually losing/gaining steps but the noise at certain speeds tells me I'm not too far from doing that. The drivers I use are xylotex, and if I reset from 8 microsteps to 4, the effect is worsened considerably, to the point of stalls at quite reasonable speeds.
-- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) ... My pants just went on a wild rampage through a Long Island Bowling Alley!! ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
