Heatsink on extruder motor (running too hot)

[marvi]

Hey all, I'm fairly new to the M2, and I've noticed that the extruder motor tends to get very hot during long prints. Sometimes I can't touch it for more than a couple of seconds. I'm not sure if it's okay for them to get this hot, so I'm attaching a heatsink to the motor. I found a couple of heatsinks at the electronics scraps store and I'm cutting them to size. I've attached pictures of the options I'm considering.

My questions though are these:
1) Do I NEED a heatsink on the motor? Or is it normal for the extruder motor to get hot?
2) If I do attach the heatsinks, will their weight on the moving carriage affect the performance of the printer? Option-1 adds approximately 102 grams to the carriage, and option-2 adds 35.5 grams.
3) Is there another simpler solution out there?

All thoughts appreciated
Marvi

[willnewton]

I have never heard of the need to put a heatsink on any M2 stepper. You may only be fixing a symptom of a larger problem causing your overheating. Most of the time, it is too much current, a wiring issue, or perhaps a mechanical issue in your gearbox.

[jimc]

normal operating temp for an m2 extruder stepper is in the mid to upper 60c range. well within kysan's operating temps. while a heatsink wont hurt anything, its definitely not needed. many people here even run their m2 in semi heated enclosures with no issues.

[marvi]

Thanks willnewton and jimc, if people aren't having issues its probably me over-reacting, or a singular problem with my machine. I'll try attaching a thermometer and monitor the motor for a bit for a better idea of the situation.

[innkeeper]

Steppers run hot... there supposed to...it is normal.

unlike motors, steppers draw basiclyt he same current still or moving..
Most hybrid stepper motors are rated for an 80c teperature rise. some are just 80c
that is pretty darn hot...
personally i don't like to see them above 70c, just to have a safety margin.
if be very surprised if your stepper temperatures are anywhere near that though.

[insta]

Steppers run hot... there supposed to...it is normal.

unlike motors, steppers draw basiclyt he same current still or moving..
Most hybrid stepper motors are rated for an 80c teperature rise. some are just 80c
that is pretty darn hot...
personally i don't like to see them above 70c, just to have a safety margin.
if be very surprised if your stepper temperatures are anywhere near that though.

Mine are probably close to that after removing the extruder motor fans.

[innkeeper]

The rated current for these extruder steppers is 1.0A.
The heat rise as you increase current is very steep.
I have played with various current settings for the extruder stepper and currently keep mine set to .90A I have run it without issue for 4 spools of pla at .5a just as a test without problems. 90% of spec is a general rule of thumb that many follow. but by no means an absolute.

If your stepper is running that hot, id check this current setting first.
Likely, anything from 1.0A or lower is fine, and i say likely because of this:
The Current and voltage spec is really just the spec at which the stepper will give its rated torque etc... but typically the manufacturer will push the stepper to it's limits to spec the maximum torque. So its a good starting point for temperature control as well.
Can you cool them to get more out of them... sure, but remember the internal temperature of the magnet is what really matters.

overheating a stepper will permanently damage the magnets inside the stepper, the hotter it gets beyond its spec the more magnetism it looses and the lower the torque it can produce after that.
That is actually where the maximum temperatures come from in the spec for a stepper, it is the maximum spec for the magnets before they start permanently loosing magnetization. ... there are specialized very high temperature steppers, but they have magnets intended for those higher temperatures also.

hence why many set current to a maximum of 90% of spec. ... it provides a safety margin.

hope this helps