Broken Stepper Motor Shaft

Hello, New to the forum… just picked up a Mini from amazon last week. Only printed about 10 small items so far. Well tonight on my first print about 3/4 way thru the print I started hearing a popping noise looked over at the print and it was ruined plastic piled up in same place making a mess. Got to looking and the X axis was not moving. Upon closer inspection noticed the shaft of the little motor was crooked and touching the frame. Noticed belt was loose. It appears the motor shaft has broken off. Has anyone else seen this happen before. I am thinking the belt must have been installed to tight and over stressed the little motor shaft. The printer is brand new so I hope I can get hold of Lulzbot Support tomorrow for info on what I need to do to get it repaired. Any suggestions appreciated…

Exactly once before. Call support, they will get you fixed up.

I’m guessing the bearing that positions the shaft went bad (or was missing to begin with). That usually means the motor is ruined though since the coils start rubbing together on the inside. You’ll probably need to replace the motor.

They will probably replace the printer.

Thanks for the replies. Talked with support this morning. Since I ordered it through Amazon I just did a return. Seems to be the quickest way. It’s only 7 days old to me…Thanks. At least I’m not the only one it’s happened to…(unfortunate for anyone of course) guessing the belt was probably just to tight.

Even the belt being to tight would not cause that problem. My guess bad bearing or shaft from day one.

I had the same issue with mine, also from Amazon. I called Lulzbot, they were very concerned, asked for part numbers and all that, but regretfully informed me I had to go through Amazon (it was less than 2 weeks old) a couple of calls to Amazon later and they shipped out a new one and processed a UPS pick up for the broke one.

Our TAZ 5’s X direction stepper motor shaft broke off, inside the motor, between the bearing and armature after only 3 weeks running. Support is sending out new motor, but in the meantime production on this machine is ‘dead in the water’. This is either a poor design choice, or an unreliable supplier. I have used steppers for over 30 years and NEVER experienced a motor failure, much less a shaft break. Anyone know of an equivalent motor from another, more reliable, mfgr?

There was another thread on the broken motors somewhere, and basically what seems to have happened is that the supplier who makes the motors that Lulzbot uses had a small batch go out without heat treatment, leading to a more brittle shaft. The motors aren’t visibly different than the 99% good ones out there until they break. It is an unfortunate issue, but it doesn’t seem to be a widespread one. the two people in this thread make 3 instances of it in the forum I have seen in total. Given how many 5 motor printers they have probably sold, thats not a horrible failure rate.

I wore a bearing out in my old AO-10x inside a stepper once. I was kind of proud of that.

This just happened to me today. Support said they’d send a new motor Monday (luckily we ordered directly from Lulzbot). It’s a real bummer this happened, now I’m going to be even more behind at work. Hopefully the new one we’re ordering won’t have the same issue.

This as also happened to mine. Unfortunately I was gifted mine from a coworker for doing some work for them. I called Lulzbot and i’m not covered under warranty. Now i’m stuck buying a new motor. Its unfortunate as i’m probably just going to sell this as i’m not going to hold onto something a manufacture won’t help with eventhough it clearly is a bad motor shaft. This printer is only 3 months old dated from the packing list.

The motors are inexpensive. You will likely get a better price if the machine is operational. It is probably worth springing for a new motor even if you are going to sell it.

The Mini is a nice little printer. You should keep it and play. :slight_smile:

Greetings all,

I just purchased my mini approximately 2.5 weeks ago. I must first say that support has been great. However, I am a bit frustrated as after two days of printing a belt snapped. Support was quick with sending me the new belt. I got the machine hooked back up, started printing and the print was going well. I heard a sound and suddenly the printer started printing thick layer of plastic on top of itself. I stopped the print, shut everything down, reloaded my project and began again. The hot end dove right into the bed and I came to realize that the x axis was not moving at all. I called support and was told that the stepper was bad and they sent me a new motor. My motor arrived about 3 or 4 days later. Before ejecting the bad motor I looked at the new one I had been sent. The chord coming off it was not nearly long enough to connect with the existing wire work. I wrote to tech that my wire coming out of the stepper of the new motor was only three and a quarter inches long. They verified that I had been sent the wrong configuration and that the Taz has a shorter wire connection. Now I am waiting for the second motor. I guess my big problem is that I think I will love this machine, but I am not happy that the 30 days I have to get a full refund have been used waiting on parts. I guess I just need reassurance that my investment was smart and that I cannot possibly get another bad x motor. I have thought about just scrapping the venture and getting a refund before my worst fears are confirmed and I am out 1350. Again, tech is always responsive and fast with getting back to me, and I have been told that 25 bad motors out of 50,000 isn’t bad–which is great when you think about it. Just not when you are the guy with the new machine with one of the 25 broken motors. I really want to stick this out but am just frustrated with my beginners luck. Anyways, thanks for listening. I guess I am comforted by the company of all of you with bad stepper motors too.

Years ago I worked as a electrian in a manufacturing plant. Sure they had QC but sometimes thousands of widgets that were defective slipped by and got to the customer. I can almost gurantee more than 40 or 50 motors were shipped. I love my Mini and had no problems other that user error. It’s a good machine, well designed and made. Hate to part with it but the toy box is getting full. :smiley:


Wow, what an amazing run of bad luck. HacDC has a Mini for months, and the machine itself has not had any problems whatsoever. In fact, the Mini is really the most robust printer out there, with its steel frame and automation.

Make that one more.

Shaft sheared clean off the Y-Axis stepper motor at the bearing and I didn’t catch it before the head went into the PEI and caused some pretty troughs therein. I intend to have more of these printers in the future with remote capability, so “fire and forget” is important to me.

I have a spare head I bought just to have around so am going to replace the stepper with that one and see if our friends at Aleph will be kind enough to send me a replacement motor and base.

In their defense, I must say that Aleph and their support and sales teams have been nothing but GREAT to work with. In my personal and professional opinion, support “makes or breaks” a product, and Aleph has been nothing but top-notch. I have Visited their facility in Loveland, Colorado and have spoken in person with their staff. They are a good group of folks that are genuinely interested in listening to customers and in finding root causes for failures in earnest anticipation of preventing them in the future.

I have no doubt they will step up as always.


Make that even one more. My Lulzbot mini always had issues moving about the Y-Axis, turned out the shaft was broken in the Y-Axis motor and it looks like it had been (glued, really?) together when it was installed. Just a few prints in, everything broke.

Add one more for the Taz 5. Just happened today, X-axis stopped moving, shaft off at an angle. Loosened the belt and the shaft and gear fell right out onto the floor. Planning on calling support ASAP to see what they say, got it at Christmas.

In a normal nema 17 motor assembly, a motor core is glued onto a high strength shaft with high temperature epoxy, which is less subject to loosening and shearing than a bolt or setscrew, or even a keyway. What seems to be happening with some of the motors from the taz 5 5.0mm nozzle and mini runs is a motor production batch that was made with unhardened shafts. Support should get you squared away. But the glue is supposed to be there.