Tilt Motor Grinding

Hello. I have installed all hardware and did the first power up. Upon turning on the power button the Z axis did some homing as expected, no problem. Then the tilt motor started to grind so I powered it off immediately. There are no screws, plates or interfering parts. The shaft is aligned with the bracket. The shaft is screwed in completely to the bracket. It appears that the tilt motor shaft is forcing the hook to bottom out. It is even flexing the tilt motor mount plate a little. If I remove the hook, the tilt motor shaft will go up and come down. Successive power on and off without the hook and the tilt motor shaft gets higher each time. I have re-applied the latest firmware again, still same problem. All the electronics are hooked up correctly, checked and rechecked. Another thread said this noise is normal. Grinding in any machine is never normal or good. Something is wrong. Could the tilt motor be bad? How does it know where “home” is? Is there a hall effect sensor or shaft encoder used in this little motor? Does it have current sensing circuit to stop it when it senses the hook against the bottom of the slot? Is there a setting that determines the distance the shaft travels?

Video of grinding

Video of tilt motor with hook removed

As a recommendation to engineering. It would be a better design to mount the bearings to the chassis and use shaft collars screwed to the frame of the tilt platform. This would allow simple positioning to align tilt motor shaft to the bracket. Wherever my tilt platform sub-assembly was assembled, they stripped 3 out of 4 set screws in the bearings. After continued vibrations they will move laterally or induce slop into the precision of the printer. Bearing set screws are never used to keep parts in place on a shaft. Set screws in shaft collars should be used. A keyed shaft would work quite nicely as well and eliminate a few parts. Thanks for any assistance.

Thats normal tilt home is found by slippage in the motor screw.

Wow. Your motor s is louder and more concerning than mine. How can this be standard issue? I would have questioned one of my engineers ability with this design implementation. Does everyone’s make this noise at startup?

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The PM motor has no feedback for homing, so on startup they just run the motor up longer than it could ever be out of position and when the hook stops it the motor is skipping steps and that is what the noise is from.

Will this eventually wear out the internals of the motor?

Not that I’m aware of. Its not a mechanical slipping or anything like that.

My Moai 130 makes the same noise at power up. Very loud, sounds like something is going to break.
I question the comment that it’s not a mechanical slipping. that kind of noise definitely sounds like the result of a physical interference as opposed to some kind of electrical squeal, hum, or pop.

It is the tilt motor zeroing out. It is perfectly normal on all Moai printers.

Hello,
As mentioned, that is the printer homing the Z axis. It is set to go up for X amount of time to make sure the Z axis is all the way to the top and then stop. It is a normal process and no need for concern.