Extruder motor gets hot during print

[SouthSideofdaSky]

Hi all,

My extruder motor is getting pretty hot during prints. Roughly 45 minutes into a print this morning, the back (flat) surface of it was at a temperature where I could touch it, but wouldn't have wanted to keep my finger on it for more than a few seconds.

I just switched to the new V4 extruder, but I believe it was similar with the V3B. A year or so ago (when I was mostly printing ABS) the motor got hot enough that it caused the motor mount to fail over time (this was with the stock mount). So to combat that, I mounted my bed fan to blow on the back of the extruder motor (since I was printing ABS, it wasn't necessary to have a fan blowing on the part). But now I'm printing mostly PLA so I'd kinda like to have the bed fan available (To clarify, I observed the temperature above with the fan aimed at the part).

So my question is: How hot do other people's extruder motors get during prints? If mine is unusually hot, what should I do about it?

Update: I searched the forum and found this other thread: viewtopic.php?f=2&t=2385&p=13150 . In that thread, the general consensus seems to be that it might be normal to have the extruder motor get up to about 60 degrees Celsius, which is probably about what mine is getting to. But I guess I'm just looking for some more feedback still. Thanks!

[Jules]

Can't say that I've noticed mine getting hot, but I haven't really hung around to touch them much either.

I did put an extra dab of "X-TRA Heavy Duty Grease" in around the planetary gears when i had it pulled apart for the dual assembly. There's a really good write-up on it here:

viewtopic.php?f=7&t=2544&start=20

Might be something to check.

[sthone]

I don't even run the extruder fan anymore and my extruder motor hasn't burnt up yet so I wouldn't worry to much about it.

You could always slap some heat sinks on it if you wanted too. (I think I saw pictures of someone on the forum who did that.)

-Steve

[innkeeper]

most hybrid steppers spec out as 80C temperature rise.
so that is basically 80c above ambient temp...with ambient tenps allowed being u to 50c!
check it if you think its too hot, but i am doubtful its hot enough to damage it.

personally i try and keep them below 80c though technically you can go much higher before damage occurs.

damage at high heat can include damaging the magnets if they get over their working temps.. which permanently make them loose some magnetism, and reduces the strength of the stepper

[SouthSideofdaSky]

Thanks for the feedback everyone. It sounds like I have nothing to worry about. Maybe I'll open the motor and grease it up a little bit just to be sure.

[jimc]

nothing to worry about. mine has been running for 1000's of hours now at mid 60c.