Need a bit of help.

[terry1956]

Hi, my mill as started to play up. When jogging the x axis, it starts moving in the correct direction,but if I press the jog button again, the machine moves in the wrong direction. And then no matter which direction I press it just moves one way. I think that there must be two wires touching, but before I start taking it all apart would like to hear from you. Anyone have the same problem and fixed it. Thanks,

[JAZZCNC]

This will 99% be that you have a loose or broken wire on the Direction terminal on the drive or at the controller.

[terry1956]

Thanks, just check wiring, looks ok, but now the machine moves. Ok one more question. How do you work out how fast the machine can move in each axis. Thanks

[JAZZCNC]

Thanks, just check wiring, looks ok, but now the machine moves. Ok one more question. How do you work out how fast the machine can move in each axis. Thanks

If you haven't found anything and now it works after moving wires etc then it's possibly a wire that is starting to break but not quite there yet. It will however 99.9% be one of the DIR wires, it's a common issue though usually, it's a loose connection rather than a broken wire.

Regards how fast each axis moves then all you can do is keep increasing the motor tuning and acceleration on each axis until the motor stalls, then back off 25% for a stable system or less if you want to push the edge.

[terry1956]

Thanks for help.

[Kitwn]

If you haven't found anything and now it works after moving wires etc then it's possibly a wire that is starting to break but not quite there yet. It will however 99.9% be one of the DIR wires, it's a common issue though usually, it's a loose connection rather than a broken wire.

Regards how fast each axis moves then all you can do is keep increasing the motor tuning and acceleration on each axis until the motor stalls, then back off 25% for a stable system or less if you want to push the edge.

Dean,
Does it make sense to set acceleration deliberately low to find the max speed, back off from there and then bring acceleration up afterwards?

[JAZZCNC]

Dean,
Does it make sense to set acceleration deliberately low to find the max speed, back off from there and then bring acceleration up afterwards?

Many ways to approach motor tuning but yes that's one way to do it, there's no right or wrong way. So long as you get the speed you are happy with and the system is stable then whatever works, works.!

[cropwell]

It doesn't have to be the DIR line that breaks. On my machine I have had the same problem with the Z axis and on the 3D printer the Y axis has failed twice causing distorted prints. The Y axis is the only one with a rapidly moving cable. The problem in both cases was a motor wire fatiguing at a connector. In both cases I have clamped the wires to remove movement at the connector (after replacing the cables).

I don't know why, but a faulty connection to a motor winding can make the stepper go in one direction intermittently.

Cheers,

Rob