Buildplate/P.head stops extruder keeps pumping!

Hi there everyone. I’ve got an issue with some of my prints where the print head starts making a loud clunking noise while traveling back towards stepper motor, then stops. Meanwhile the extruder is still pumping out the filament and the build plate carries on as if nothing was wrong.
Occasionally the situation is reversed, plate stops and head carries on. Either way, the stopped component’s stepper is off and that component can be easily moved back and forth by hand.
This is intermittent and appears to be only on large parts, but not always.
I’m designing in Fusion and slicing with Cura. I’ve redrawn parts and re sliced multiple times, reoriented on the build plate, printed slower, etc.
Printing a small part now which did the same thing last night and again this morning when sliced on it’s side, but so far is printing fine standing up on end.
Any ideas?

Thanks in advance,

are the motors really hot when this happens?it sounds like a slicer problem until you say the motors can freely move by hand which indicates they have no power


Hi Glenn. I’m not sure about temps. Didn’t think to check at the time. I will be bringing my IR temp gun home from work this week and will check them while running good to get a baseline and then if/when it jigs out again. The print I started this morning (the one that stopped on me twice yest while printing horizontal) is still going now, vertically. I will re slice it horizontally once this print is done and try it again with all these setting and see what I get.

Don’t worry too much about the thermometer for the steppers. If you can’t hold your finger on it it is too hot. it is odd that a filament would extrude and stop and start again. I had it happen because of over heating / slicer the direction Glenn is pushing. I agree that is a possibility. In the effort to look at other possibilities, could the filament being snagged on something? Or could the filament holder be jamming at a certain level? Did you try a different slicer?

Hi Kitedemon. The extruder appears to be working fine. It isn’t stopping, either the x-axis print head stops or the y-axis build plate stops while the other carries on like all is well and continuing to extrude plastic back and forth, making the long mess that you see in the picture. I only have Cura at the moment but am going to get something else to try that.
Something seems to be shutting down one of the stepper motors mid print, without affecting the rest of the operation.
Thanks for your time with this.

The stepper motors drivers on the controller board have an built-in thermal protection system. Usually when the drivers over heat, it’s reflected in excessively hot stepper motors, but the stepper motors do not have a built-in thermometer so there’s no way the controller can actually know they are overheating.

In extreme cases, a stepper motor can overheat to the point where thermal expansion will cause it to seize internally, but then it won’t turn freely. If it’s turning freely afterward, that indicates the power has been cut off and the guilty party is the stepper controller on the controller board.

Two possibilities come immediately to mind:

  1. Has the heat sink on the stepper controller chip fallen off? That does happen, particularly if the adhesive was weak in the first place, but you indicated that it happens to more than one axis, randomly and it’s unlikely that more than one heat sink fell off unless the printer was dropped, sooo…

  2. Given multiple random failures, I’d be taking a good hard look at the controller cooling fan in the case. My guess is it’s either blocked, or otherwise failed.

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ewww! that’s a good one the BTT fans are no good for sure and my chipset fan was the first to go on my B1.
Here it is

there is also one perpendicular to the indicated on that goes through the side of the case that also can be bad (bottom of the photo)

OP check belt tension and the movement of the Axis. make sure everything is correct. It is a simple thing if a belt is slipping when there is a bit of load.

I have had a stepper over heat melt the casing around it, It was hot very very hot, too hot to touch. I replaced it and the extruder in my case started to behave. It would stop dead and do nothing when it was too hot.

The fact you are getting a line looks to me like the bed is not moving. The x axis seems ok.

I’d check the belts on the bed before I took the main board or steppers apart. If it is a new printer do not disassemble it so you void the warranty. The manufacturers need to take responsibility for shoddy work that 3d printers are plagued with.

Good morning to you all. WOW, thank-you for the replies, and I apologize for the delayed response. First off, I just finished a 14 hr print that jigged out on me within an hour twice before!! And guess what? It’s approx. 15* cooler and far less humidity than the days when I had problems.

I think Legomaniac is on to something. At start up, there is a bad bearing/bushing noise coming from the fan on the side of the case and I planned to change that soon. the noise goes away within a minute and I assumed all was ok. I was unaware that there is a second fan just inside the case that may actually be making that noise. So, will definitely be getting a replacement for that.

To Kitedemon, you’re absolutely correct, in that situation it was the bed that stopped, but as I mentioned it is occasionally the x-axis that goes. this thing likes to spread the misery around!!
I have checked belt tension and all seems ok. I have check for any “gear lash” between pulleys and belts, seems ok. And again, just finished running this thing for nearly 24 hrs and no issues.

As far as warranty goes, I’m not sure about that. I’ll check with my Dad when he got it and what the situation is there. he hasn’t had it very long so I’m sure it is still valid now that I have it. that may be a problem. We’ll see.

So I’m just finishing up modifications to the part pictured above and will try and print today while I’m around to keep an eye on it and pull the pin if necessary. Fingers crossed, wish me luck and again, thank you all very much for your time and experience with these things.


If you think the board is over heating a temp trial solution could be just placing a fan pointed at the vents.

…Or take it to your Ex’s house and let the icy gaze cool it down.

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LOL I am lucky my ex (s) all talk to me on the regular. We get along very well. No icy gaze. lol.

Good morning to all.

Well, 15 hrs and still going fine. Appears temps may be the problem. Also, I fought off impatience and slowed the print down a bit from speed settings I was printing other parts at.

I’m still married but occasionally get the icy gaze, which is laser focused on me and not so much at the printer. Maybe I should do something stupid and stand beside the printer!!!

Thanks again

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