Extruder motor getting hot while print paused
I was testing some flex filament. I think the root cause of the problem is the high temp of the extruder gears, not the filament route. If the Bontex gears get too hot the filament will stick anyway. So I thought that I will pause the print when the gears get around 60C. (starting at 25C room temp it took about an hour, the print went well until that) But after selecting Pause I was surprised that the motor was not cooling but getting even hotter. All the other motors are about 35C, but the extruder motor is 60C and slowly rising while I write this. The extruder is already cold. I don't think that this is good so. Can you measure your extruder motor temp in while in pause?
Re: Extruder motor getting hot while print paused
The holding current of the E axis motor, is the same as the running current.
That means that the motor draws ROUGHLY the same amount of power regardless of if it is turning or not.
When you pause the print, the motor is being "held" in place. That is why it will not cool down, as it's not actually "off".
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Re: Extruder motor getting hot while print paused
Yes, I know that the holding current is warming the motor. But what 's the point? Why hold the E so hard during pause? E axis at 70C, while the others are only 35C. If the print is resumed, the motor cools down to 60C. And anyway, 70C at 25C room temp is too much for the motor. In the summer with 35C room temp it will go over 80C. I don't think the magnets will love that.
Re: Extruder motor getting hot while print paused
Yes, I know that the holding current is warming the motor. But what 's the point? Why hold the E so hard during pause? E axis at 70C, while the others are only 35C. If the print is resumed, the motor cools down to 60C. And anyway, 70C at 25C room temp is too much for the motor. In the summer with 35C room temp it will go over 80C. I don't think the magnets will love that.
Re: Extruder motor getting hot while print paused
In the summer with 35C room temp it will go over 80C. I don't think the magnets will love that.
Don't do like I did, and leave the current up on the motor.
I was like "OH NOES, I think I left the extruder motor current too high! *sticks finger on it*
Hmmm how... *finger sizzles*
HOLY @*#*$#&@*&.
It was 96c when I got my first reading after turning the amperage down.
And I have it bolted to PLA. Gonna have to make sure that's OK once this 12 hour print finishes.
Hi, I'm Sean. I used to work on CNC machines.
I try to not make mistakes, but the decision is YOURS.
Please feel free to donate to my filament/maintance fund.
Re: Extruder motor getting hot while print paused
Yes, I know that the holding current is warming the motor. But what 's the point? Why hold the E so hard during pause? E axis at 70C, while the others are only 35C. If the print is resumed, the motor cools down to 60C. And anyway, 70C at 25C room temp is too much for the motor. In the summer with 35C room temp it will go over 80C. I don't think the magnets will love that.
As far as I can see, there is no special pause state. So the E value is still the same like for printing. Because you're not moving the head, motor gets warmer. If you have paused in an unlucky mid-step, you're drawing pretty high current in addition.
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Re: Extruder motor getting hot while print paused
Coming firmware will lower e current if I understand GitHub correctly. Latest pull request from XPila
Re: Extruder motor getting hot while print paused
Coming firmware will lower e current if I understand GitHub correctly. Latest pull request from XPila
His pull request is lowering the E-value by 28.5%. This should definitely cool down the stepper a little bit.
Just to be precise, you should still see a heat up during pausing the print.
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Re: Extruder motor getting hot while print paused
Great news. 28,5% less current gives about 50% less dissipation. Temperature will drop significantly and I hope that most of the flexible filament printing problems will disappear if the teflon tube is in good form and the gears are clean. Let's see. 🙂
Re: Extruder motor getting hot while print paused
I can confirm that the firmware update to version 3.2.0 has solved the problem, the extruder is not getting hot like before.
Flexible material printing is working great. 😀