Small X Y offset between jobs

[lithoss]

Hi all,

Been having a problem i can't seem to figure out on my own.

The machine runs beautifully during jobs, very precise, no problems. However, whenever a job finishes and returns to "home" (G0X0.0000Y0.0000), it's always off by 2-3mm in the X and Y axis. I cannot figure out why. So if i run the same job over and over, it's identical except it keeps slowly moving away in the X+ and Y+ direction.

Here's a simple g-code example i made for troubleshooting, but it happens on every job I run.

test5.zip

I've tried generating the code with Vectric Vcarve and Easel, same result.

I've ruled out router on/off m2/m3 interference (running it manually directly connected to AC the whole time has no effect). Not sure what else to try.

Any suggestions would be greatly appreciated.

Thanks!

[lithoss]

Upon some further experimentation, it seems like the system is losing/improperly executing the very first X or Y movement.

If I add a little X test run to the beginning of my g-code:
G91
G0X1.0000Y0.0000Z0
G0X-1.0000Y0.0000Z0
G90

All subsequent jobs will be off in the X direction, because the first G0X1.0000Y0.0000Z0 was not executed correctly.

If i instead add a little Y test run to the beginning of my g-code:
G91
G0X0.0000Y1.0000Z0
G0X0.0000Y-1.0000Z0
G90

All subsequent jobs will be off in the X direction, because the first G0X0.0000Y1.0000Z0 was not executed correctly.

I'm using STEPPERONLINE DM556T for the X and Y axis and one TB6600 for the Z axis.

[lithoss]

Disconnecting the Ena- to each of DM556T's so that they are always enabled with power on fixes the issue completely.

Is there any way to turn on the Ena- for the axis' a little bit earlier? My theory is that the DM556T's enable circuit takes a little bit longer to take effect than the TB6600's does?