I have a 2016 shapeoko 3 xxl with an upgraded z-plus axis. I recently noticed the Z carriage seems to be stuttering when going along the X-Axis.
I took off each v-wheel individually and inspected for cracks and bearing issues, all seem fine. I tightened the eccentric nuts back up to where they can move the carriage if rolled, but not too tight.
The stuttering persists. It happens when cutting an air job too.
Could this be the X motor, or something to do with the bearings/rollers for the belt? (the belts were replaced when the z-plus was added, as were all the v-wheels and eccentric nuts).
I tried to capture it on video but the stutter can’t really be seen. You can feel it in the whole carriage as it moves on the X axis though.
Is all the motor wiring in good condition and all connectors secure?
Power down and remove both Y-axis belts, put a bit of tape on each Y-axis pulley so as to better see the rotation, then power up and connect to the machine and try to initialize — the machine should home the Z-axis as normal, then try to move both X- and Y-axes — the X-axis should home as normal, while the Y-axis motors should turn until they time out — do they turn evenly and in synch?
The X-axis is mechanically simpler, since it only has one motor and belt.
Remove the belt and the X-axis motor and check the condition of the belt and the pully and how it lines up with the idlers. Put a witness mark across the pulley and motor shaft (for future reference). Reassemble things, swapping the belt end-for-end if it was in good condition and test things.
I removed the belt and checked the pulley, which both seem fine. I swapped the belt ends and checked the pulley allen screws which were tight. No change after that. With the belt off though, it seems like the stuttering is still there. I backed off on the tension on the v-wheels a bit, and it seems like that actually helped a bit, definitely less stutter… I can still feel it though, and now I’m not sure I am remembering what “normal” should be like.
Bearings on the v-wheels are smooth and spin freely? Almost sounds like a bad bearing or something. No debris on the rails? The rails on mine usually get small chunks of debris stuck on them so I have to scrape them clean every so often. Can cause a stutter feel to the X axis.
Does this happen when you run a “simple” program, like cutting out a rectangle? Without knowing more, we can’t rule out that the gcode itself is the issue.
Yes, I could actually feel it happening with the belt disconnected moving it on the rails manually. It happens when jogging too.
These v-wheels were replaced when I upgraded the z-axis this year, I’m wondering if one of them may be failing and I’m missing it (I don’t see cracks and they spin freely, but I guess it could be warped or something).
It has been a while, but I think I pushed the bearings out of my v wheels and found black stuff (wheel material ?) inside. I also seem to remember that some of the wheels would spin easy (off themachine) until pressure was applied to them (on the machine), then you could detect roughness. Cleaning the inside of the wheels improved it.
Thanks for the suggestions. I inspected them again and they seem OK. If left the v-wheels slightly looser than what I would think is OK, and the stuttering seems greatly reduced. I think time will tell if one of them may be bad, or if I just had them way too tight.