Stepper motor making a weird noise

[GeorgeS]

Hi everyone,

I am converting a WM16 with the stock leadscrews until I can afford ball screws. The X and Y axis work fine, and the Z axis works fine moving up but when it moves down there is a horrible noise. I dont think it is skipping steps as it seems to be accurate but I dont want to damage any hardware (and its annoying). The noise is worse when it is moving slowly and gets better when I tighten the Z axis locking screws slightly, but then it struggles to move up. I'm thinking of getting a gas spring to take some of the load off the motor. I am running LinuxCNC.

Any help would be great.
Thanks

[Clive S]

The WM 18 has a gas spring in it, have you checked yours.

What size motors and what micro steps are you using have you put a belt reduction on the motors. I have done two conversions with the WM18 but used ball screws with nema 23 3.1Nm and linuxcnc

[GeorgeS]

Theres no gas spring that I can see on the machine or in the column.

I'm using 4nm nema 23 steppers with no belt reduction and half stepping.

[Clive S]

Theres no gas spring that I can see on the machine or in the column.

I'm using 4nm nema 23 steppers with no belt reduction and half stepping.

I think I would increase the stepping and adjust the scale accordingly. I would also put a reduction belt on the Z axis

[GeorgeS]

Thanks, I've changed to a higher step count and it seems to have worked. I'll probably add a belt drive at some point too.

[Neale]

Yes, a stepper motor using full or even half-steps sounds like marbles in a concrete mixer! However, torque falls off as the microstep count goes up so there is a balance to be struck. Around x8 or x10 seems to be generally agreed to be a good compromise between smoothness and loss of torque. As long as whatever you are using to drive it can cope with the pulse frequency, anyway.