Repairing a stepper motor? (Dead Z)

[thecadman99]

The Z stepper on my M2 has a problem. Whenever I send a command to the axis, or try to print, it simply grinds and shudders.
It does the same when connected to the Y controller so I'm sure its the motor and not the board.

It turns freely and smoothly when its not powered.

My question is can I repair it? I have a spare motor, but it is a standard shaft (not the long threaded shaft as on the Z).
Can the internals be swapped?

I should note that this motor has many, MANY hours of print time on it in the past year and a half.

Thanks for any advice.

[jimc]

Going off memory the z motor is smaller than the xand y. im no authority on steppers but they are very specific in voltage requirements so if the z is different i wouldnt even mess around with it. Just order the correct one from makergear. If your machine is older that had the z stepper that got really hot then that may explain the failure. If thats the case then the new stepper is different and there may be some firmware changes. Im really not sure. You had better just contact support on it.

[jsc]

If you are a handy DIY sort of fellow, you might find this link (and further related posts) of use: http://softsolder.com/2013/06/28/makerg ... ransplant/

[thecadman99]

Thanks Jim
Yeah, I just ordered the motor from Makergear.

The one that failed was on the older 12v model, and it did tend to get hot despite all the heatsinks I had on it.

I haven't had any problems so far with the newer 24v models.


Wow, I had just read that exact page JSC, if this motor dies an untimely death, I may give a slightly larger motor a go (with adjusted firmware).
Thanks guys

[jimc]

well mine is a 12/19v machine as well but my z stepper has always been ice cold. its the small one in ed's blog post. there was a change at one point though. we just had this discussion an month or two ago but i dont remember what that change was. maybe it was just the model # of the stepper or perhaps it was some voltage changes in the firmware. i dont recall. when you get you new motor it should run really cool.

[Tim]

I had the old motor on the 12V/19V setup; it got very hot, which correlates with the resistance across the terminals. If it gets hot, it's like the one reported by Ed Nisley in the softsolder.com article that was cited; if it runs cold, then it's the one they substituted after word got out that the high-resistance motor was not the right kind to use for the Z-stepper. Mine also died recently, with the same symptoms, so it looks like they really do have a very short lifetime. Mine lasted almost exactly two years with on-again, off-again printing. I think that upgrading to 24V with the same motor hastened its demise.

[thecadman99]

I bet our motors lasted almost the same number of hours Tim.
I had some time to tinker and after having a couple of extruder pinion gears wear down on me, I had the extra extruder motor and thought I'd give it a go as a Z motor.

I cut off the threaded rod from my broken Z motor (it was surprisingly soft and easy to cut with a rotary tool and heavy duty cutoff wheel).
I cut off the gear from an extruder motor, and ground a flat on the shaft.
Drew a connector with captive nuts, printed it up (on another printer of course) and put everything together.

I believe the extruder motor is only rated at 1a versus the 1.5a of the stock Z.

So far I've printed about 3 hours and the motor is barely warm. I lost a little Z, but I rarely print that tall anyhow.
I'll get it swapped out when my new motor gets here, but hey, if you're in a pinch to get a job done, it works.