Is my Z-axis Nema Stepper motor fried/broken ?

Quote:

Originally Posted by Wao

Hello,

I have been using this OMNI 3 axis CNC for a few years without any problem, but suddenly the Z axis is acting funny.

I have no knowledge whatsoever in electronics or even basic electricity, I just know how to use my CAD/CAM softwares and this machine.

The Z axis is sometimes moving smoothly when controlled manually with the controller but will start to slow down and even stop with a sort of grinding sound. I have checked that the rails and screw are well greased. When using the faster speed with the manual controller it jams almost every time.

Also one green light is off on the driver for the Z, but two lights are on for the X and Y axis.

I just want to know if I just need to buy another Nema motor (Nema34 I think) and if it is doable for a dummy to replace or if it needs knowldge to calibrate or I don't know what...

I am in a region in Asia where it will be difficult to find a CNC tech, so I'm hoping to fix this with your help. This obviously happens when I really need to get some work done :)

I am uploading a video and a picture, but I had to put the video in a zip file because this website allows only very small files :( The quality of the video is bad but the sound should give knowledgeable people some hints. When it's smooth the sound is this sweet robotic sound but when it jams it starts to sound crunchy...

Any help appreciated !

Since you’ve already confirmed that the rails and screw are well greased,
you can also check if there’s any mechanical obstruction or misalignment in the Z-axis assembly.
Even a slight misalignment can cause jams at higher speeds.