Fans on Stepper Motors

Ahhhh!!! I feel dumb, well, never mind. The one in the video is next level x 2 anyway. :crazy_face:

An earlier post in @kwledbetter 's thread did have fans:

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True, didn’t see that. :smiley: So maybe you linked to the wrong post @ScrapheapInd :stuck_out_tongue: You don’t have to feel dumb any more. :smiley:

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Vindication!!!

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V1 has the politest disagreements on the Internet.

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Ya i was trying to trick everyone. No really i just took them off for now as the motors are not even warm but i have only done minures long prints. Once i get into hours i may reassess.

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I’ve installed fan’s on mine, although I come from a place of zero CNC experience… and haven’t even started producing any chips yet.

I saw and read comments about steppers skipping, thermal shutdown and melting PLA, much of which has now been explained to me as unlikely. However, before that I decided to take advantage of my control board having multiple fan outputs, and run the wiring from the beginning. I’m also planning to enclose the work area, so wanted to preempt any issues given the minor cost increase.

I agree with you. While I am not going to do fans at the moment, I will run some spares out to each motor for whatever may come up in the future.

That because none of us RTFM :slight_smile:

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Mainly, it’s because we can never find a decent second for a duel… Everyone assumes we’re talking endstops, and by the time the whole dual/duel kerfuffle is straightened out, we’ve forgotten what we were arguing about. That, and it’s expensive to get everyone to New Jersey (everything’s legal in New Jersey).

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And we would all have our guns disassembled for the newest mods anyway.

I have seen heatsinks and fans mounted on steppers in the past and have a couple comments.
Steppers are made of steel which is not a great thermal conductor. If you put a heatsink at one end of the motor, it isn’t likely to do much for the temperature at the other end. The thing that causes heat in the motors is current in the coils of wire inside the motor and those wires are not particularly well coupled to the steel stator plates that the heatsink/fan would be trying to cool (usually at one end of the motor). If you set the drivers so they don’t exceed the motor’s rated current (normal practice is to set it a bit lower to keep noise and vibration down), the motors should not overheat.

For these reasons, I don’t think either a heatsink or fan will do much to prevent motors from overheating. I’d really like to see images from a thermal camera showing a motor before and after heatsink/fan are added. That would convince me that it is worthwhile.

I would not use printed PLA to make a stepper motor mount (or anything else that has any chance of being exposed to even moderate heat, including the possibility of the machine being left inside a car or truck that happens to get parked in the sun). PLA softens and deforms at low temperatures. It is not for use in anything that you want to last.

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Does running steppers with higher voltage power adapter (e.g 24v instead of 12v, or higher even if board’s motor voltage, and stepper voltage allows) enable the same torque with less current, resulting in less heat being dissipated by the steppers? i.e. boost voltage to max allowed before figuring out if fans should be added?

Higher supply voltage will consume less current from the supply, but the current to the motors will be the same, so motor heat and max torque are the same.

I designed a fan shroud for my primo’s z-motor… was 75C during summer without it, dropped to 55C with it (yes I still use PETG):

https://www.printables.com/model/322140-stepper-motor-cooling-fan-nema-17

You will generally get more motor heat when you up supply voltage. Not so much from the i^2r in the coils, but from dB/dt losses in the ferrous stator (Lenz effect). Even if the peak i and v going to the motor is roughly the same, a higher input voltage reduces the rise/fall time of motor voltage and current (it’s how we get the extra RPM out of it), which unfortunately also increases dB/dt losses and adds to heating.

I honestly was hoping I would have cooler motors after going to 48V, but it turned out to be the exact opposite. Fortunately it was within spec to fix with just one 40mm fan (X/Y motors stay around 55C without fans).

[edit: Probably goes without saying that my setup is far from stock, but I figure I should mention I did not need fans at all when running 12V, even with PLA mounts.]

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Interesting! Thanks for that insight!

Mark, I know you are not new here. This is very common here.

Pla gets plasticy around 65C, IIRC. For that reason, the MPCNC and LR motors should be kept under 50C (that is the rule of thumb).

I know your machines push things to the extreme. But PLA can very safely hold a stepper motor.

Man, I hope so! :grimacing:

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15C is a little close for my taste. I have seen quite a few reddit/forum posts from people who used PLA fittings to hold the t-slot frames of their 3D printers together, as well as motor mounts, etc., report that they took the printer to a friend’s house or a maker faire and left it in the car for a while and came back to find it hopelessly distorted.

I have used ABS for motor mounts and belt clamps with no problems, and would probably trust PETG more than PLA for either of those tasks. I used ABS in Arrakis, but those motors barely get above room temperature. When I built UMMD I used rectangular aluminum tubing to make motor mounts for the XY stage. Very rigid, cheap, fast, and easy, and maybe even transfers some heat away from the motors (one end, anyway). All you really need to make them is a drill press, a hole saw, and either a band saw or a hack saw. I mill the cut ends to make them look pretty but it isn’t necessary.

You do know this site is for the Mostly Printed CNC, right? Where thousands of people have been mounting motors with PLA for seven years?

Yes, leaving it in a car or under a tarp can be a problem. But that has nothing to do with the motors.

Since we switched to control boards like the rambo and skr, the current settings are controller by preconfigured firmware and it is not a common problem. You will find examples in the forums. But it is not a common issue.

15C is the difference between 60F and freezing.

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