Gene Heskett wrote: >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. > > > Gene, I am using full step drive and am sure that micro-stepping could have been a solution. That would have meant that I would have to replace my drivers which are designed only for quadrature drive. I may do a magazine article on this solution and will let you know when that happens.
Jack Ensor I may do a magazine article on this solution. I'll let you know ------------------------------------------------------------------------- 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
