Brand new (<1week) stock TAZ5 X-axis stepper getting VERY hot


Very excited to be here, now that I am the proud owner of a Taz5.

I’ve been set up and printing for a couple of days now, and everything is going pretty well… Still trying to get it really dialed in, but prints are looking pretty great already.

My only issue so far is that I’m noticing my X-axis stepper is getting very hot… IR thermometer says almost 60 deg. celsius. The others all seem to be running from 20-30 degrees celsius.

On my other printer (older model printrbot simple) there was a pot on the electronics you could adjust for each stepper when this started to happen. Is there something similar on the TAZ?

I have some 40mm heatsinks which might help, but I’d really like to fix the problem so the motor doesn’t burn out in a year if possible.


Thats a normal temperature for the stepper, no need to change something. They are ratet for 80°C, see the datasheet here.

The Rambo boad has digital potentiometers, you can change the current when you edit the settings in the firmware and flash it. Of course this will reduce the torque…

A heatsink zip-tied to the top of the motor wouldn’t hurt as long as it doesn’t impede movement.

I’m with piercet, its probably not necessary. If the printer is enclosed, or you print at a higher speed the heat could become an issue.

Best bet is to just buy a spare KYSAN NEMA 17 motor or two…

Okay cool sounds good. Thanks!


did changing the stepper resolve your issue?

We’re having a very similar issue with our 11 months new TAZ4 now.

The extruder/feed stepper overheats (reaches 91°C) after 10 to 15 minutes of printing time.
Then the filament-feed stops moving or only moves very sporadically. Everything else continues on as if nothing had happened,
but no more filament get’s extruded. Obviously prints are getting ruined.

I cleaned and tested the big cogwheel for resistance, but did not encounter any.
I ran a print with the filament removed, the filament tension mount relaxed in order to reduce any resistance the stepper might encounter. Still overheated.
Then I tried attaching a big passive heatsink. That bought as an extra minute but did not really solve the problem.

Thus my original question: Did exchanging the stepper solve your issue? Or was it something else?

My first impulse would have been to reduce the amperage feeding the extruder, but the TAZ4 Electronics don’t seem to allow any adjustments, so I left them alone.

Any Suggestions for what we could try to fix / further debug the problem?

As a electrician who has worked with industrial motors and such, the 90C is not a concern, except for the grease in the motor bearings. Generally speaking the cooler the motor runs the longer the grease lubricates without failing. Really high temperature applications require a special grease.

That’s an interesting piece of information to know. Thanks. :slight_smile:
It could very well be the reason our extruder motor fails repeatedly as soon as it goes above 90°C.

At this time however I’m not looking to exchange the grease in the motor, but rather to find out why
it overheats (when nobody else seems to have this problem) and then FIX the problem.

First thing I’d like to try is to replace the stepper with another one of the exact same model.
Turns out however, that exact model is not so easy to get except from Lulzbot’s Shop,
and I just ordered a bunch of stuff from them. So now, ordering just the motors, the shipping expenses
I just thought I saved on, would exceed the cost of the motor. *grml

Thus I’d like to get some input on what else I could try, instead of replacing the stepper.

You could try adding heatsink to help dissipate the heat. They are best position at the top of the motor, but that obviously can’t happen for the Y or Z motors… it can for the X motor.

Jup, I tried that on Sunday. Sorry I forgot to mention that.
It helped, but bought at most an extra 5 minutes of printing, so not nearly enough. Maybe with an added fan, but that’s still not fixing the problem just mitigating the symptoms.

Al right! We fixed it!

Finally had some time to take a look again and of course it turned out to be the obvious problem after all.
My original estimate of what constitutes “no resistance” was too optimistic.

Someone ever so slightly tightened the M10 nut of the bolt conveying the filament which has the big cog on it’s other side.
The result being, that the washer pressed on the bearing and put the brakes on the extruder motor, causing it to overheat.

Still took us an hour to find it and only after completely taking the extruder apart.
The moral :slight_smile: Don’t tighten screws that look loose, when they are supposed to have a bit of clearance. (and tightening them does nothing for accuracy)

Or so we thought. Unfortunately we were wrong and the stepper is still getting hot.
Moved to since we are now investigating the digital potentiometer and the firmware current limiting.