Losing steps
I am having trouble with my mill, it seems that I am losing steps. The mill is set up as follows...
1986 Hurco SM1 Stock ElectroCraft Servos and encoders, Larkin Viper 200 drives, Smoothstepper, CNC4PC C23 BOB, Dura Pulse GS3 VFD, Mach 3
I am using an indicator mounted in the spindle, I zero out the indicator on a bar clamped to the table parallel to the Y axis. I then make a G1 move in the X axis of -1.000" and then insert a 1" Jo block. With the feed rate set to 4 IPM the indicator reads .000. I then rezero my indicator on the Jo block, remove the block and make a g1 move in the X axis back to 0. The indicator will read -.0015. I did this 3 time at this feed rate and had the same results. When I increase the feed rate to 6 IPM, I get an indicator reading of .001 on th first negative X axis move, but it is off -.035" on the move back to 0. If I increase the feedrate to 10 IPM I get .006" on the negative move and .067" on the move back to 0. If I do a G0 move it is off almost .185" on the move back to 0, sometimes the axis will error(red light flashing)on the G0 move.
I've done some testing in the Y and Z axis and don't seem to have any issue, the indicator reads within .0005" both directions.
Any idea what might be happening?
Thanks
Tom
1986 Hurco SM1 Stock ElectroCraft Servos and encoders, Larkin Viper 200 drives, Smoothstepper, CNC4PC C23 BOB, Dura Pulse GS3 VFD, Mach 3