I’m having an issue with Z wobble on my MPCNC Primo. When I grab the motor from above, it moves slightly back and forth, which indicates there’s some play.
Some details about my setup:
The tube is 25mm stainless steel, with a tolerance of ±0.2 mm.
The printed parts were made on a Bambu Lab, which is well calibrated, so I don’t think it’s a printing issue.
I’ve tried tightening and loosening all screws, and other adjustment methods, but the play is still there.
I’m considering making a part that wraps around the bearing, making it slightly larger so it touches the tube, but I’m not sure if that’s the best solution.
Has anyone experienced something similar or has suggestions to eliminate Z wobble? Any ideas would be very welcome!
Did you try tightening the core tension bolts. This is what adjusts the looseness in the core to rail clearance.
I THINK that on the LR4 they are the top two bolts (I only have an LR3, and on that model they are two of the lower bearing bolts). Use very small adjustments, 1/4 turn or less per try.
No, that’s about the worst solution. Please don’t do that.
If you have that problem, it can be fixed if you take the core clamps off, then tighten the screws that hold the bearings first and then screw them back on, so the reverse order from what the instructions tell you to do. That fixed it for me back in the day and this tip has helped at least three more.
Thanks a lot for the tip! I tried the method you suggested, and on top of that I slipped a screwdriver between the bearing and the clamp to push it further down. With the screwdriver in place, I tightened the screw and now it’s rock solid, zero play!
Sorry, let me rephrase - should the bearings in the clamps (as opposed to the ones holding the clamp to the core) be able to spin freely, or should the clamps create some degree of torque and if so how easy should it be to turn the bearings?
So once the clamps are tightened on the bearings, and they go back on the core and the rail, how freely should the clamp bearings move when they are in contact with the rail?
I ask because I keep getting wobbles unless the clamp bearing is basically unable to move unless the core is moving on the rail. It’s almost like there’s a razor thin margin to get no wobble and still be able to move.
