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Extruder motor quite hot  

New Member
Extruder motor quite hot

Dear all,

I just finished to assemble my MKS3+ and made the first prints with it - i am very happy with the results.

I observer however that the stepper motor of the extruder is quite hot (i have no IR thermometer but i can estimate its temperature as fairly above 70 C by comparison with the bed at 60 C). Also, by searching on the net, i found some people complaining that their extruder hot motor heats also the extruder gears making therefore the extrusion of PLA impossible after some hours...

So I have some questions to the community:

1. Do you experience the same high temperature on the extruder motor?

2. I spoke to the Prusa support (excellent support, by the way) and they told me there is no problem as the motors are designed to work up to 100 C. This is fine, but i still don't understand why it gets so hot. I also have a Prusa MINI, and its extruder is only warm during operation. Also for the MKS3+, all other motors are only warm, why only the extruder motor gets so hot?

3. Do you have any other comment regarding this point?

Thanks a lot, 

Happy printing!

Posted : 09/10/2021 9:19 pm
Honorable Member

Keep in mind, that extruder motor is directly above hot heatbed (that's not the case with Mini). Stepper motor gets warm by it's own, but in this case you additionally heat it up with 60C+ coming from below.

[Mini+] [MK3S+BEAR]...
Posted : 09/10/2021 10:23 pm
Illustrious Member
RE: Extruder motor quite hot

The more resistance is applied to the stepper, the warmer it becomes. Possibly the filament supply is blocked somewhere or the friction is too high. If you can't bring down the temperature at all, you can either cool passively or actively. I myself have mounted a Noctua fan (40x40x10mm) and was able to lower the temp. by about 15 degrees C..




Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen....
Posted : 09/10/2021 11:05 pm