If by cogging, you are referring to the lack of torque by the presence of the lack of current to the motor, I would check the wires coming from the motor to see if there is any chafing, causing either shorting, or a connection issue. This happens on older motors due to the method of holding the wires steady using zip ties or other form that can cut the insulation of the wires. If you see this phenomenon only at specific locations on the axis, then wire chafing could be the culprit. But, can also be friction on the lead screw/anti-backlash nut.
Check the anti-backlash nut for any presence of oily debris. Remove this debris and re-lubricate the lead screw.
Check between the coupling at the motor shaft and the bearing that is positioned against the coupling. There should be a small outside diameter shim washer between the coupling and the inside race of the bearing. If there is no shim washer, then the coupling is rubbing against the outside race, causing friction, or binding.
If these methods do not work, please submit additional information on this FAQ page using the additional information button and a new solution will be submitted by us.
Thank you for your quick response. I found the Z-axis binding with the anti-backlash nut. What would you recommend to lubricate the anti-backlash nut and lead screw?
I would recommend using 3-in-1 oil to lubricate the lead screw and the anti-backlash nut. Don't worry about the material of the anti-backlash nut breaking down since it is made of Delrin, a plastic that can be exposed to lubricants and oils.
Click the link to respond:
My Z axis stepper is "cogging," new problem on an older machine, any solutions?