The front bearing is loose

[Gayatri]

Excuse me, I have a question for everyone.

I'm using a Nema17 stepper motor directly connected to a T8 leadscrew on the Z-axis of a DIY mini milling machine, without a leadscrew support. After three months, the front bearing of the motor has started to move axially.

Stepper motor bearings are designed to withstand radial loads and a small amount of axial force. The axial thrust of the leadscrew is directly applied, and the bearing can't handle it. Now the motor makes abnormal noise when idling.

The space is too tight to add a support. Is there any way to transfer the axial force to the machine frame? For example, could I add a thrust bearing at the end of the leadscrew and use a coupling to transmit torque but not axial force

Has anyone encountered the same problem as me? How did you solve it?

 

[telnar1236]

Excuse me, I have a question for everyone.

I'm using a Nema17 stepper motor directly connected to a T8 leadscrew on the Z-axis of a DIY mini milling machine, without a leadscrew support. After three months, the front bearing of the motor has started to move axially.

Stepper motor bearings are designed to withstand radial loads and a small amount of axial force. The axial thrust of the leadscrew is directly applied, and the bearing can't handle it. Now the motor makes abnormal noise when idling.

The space is too tight to add a support. Is there any way to transfer the axial force to the machine frame? For example, could I add a thrust bearing at the end of the leadscrew and use a coupling to transmit torque but not axial force

Has anyone encountered the same problem as me? How did you solve it?

I think you pretty much hit the nail on the head - if you have too much force for the motor to handle you need some way to absorb that force - you might not even need any kind of fancy coupling, just something a fair bit stiffer than the motor and motor mount

 

[Jerome01]

You're on the right track—a dedicated thrust bearing or bearing block is the proper way to take the axial load off the stepper motor. The coupling should only transmit torque while the Backing bearings handle the thrust, which will prevent further damage to the motor's front bearing and eliminate the axial movement that's causing the noise.