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Author Topic: Extruder Stalling Problems  (Read 1630 times)

ccox

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Extruder Stalling Problems
« on: September 08, 2013, 10:20:34 PM »
One of my extruders (the one I haven't been using, of course) has a problem: it stalls while extruding.
I'm able to push the filament through with light force while the lever isn't locked - so the head is clear.  And while the lever isn't locked, the gear turns just fine. But once the lever is locked, the motor starts making clicking noises and not moving though part of the revolution (while working fine, and sounding just like the other extruder, through part as well).  Once it stops though, it won't start tuning again until I unlock the lever and let it turn about 1/4 rotation.

Yes, I checked the lock screw: it's tight.  Yes, I've cleaned out all debris from the drive gear.  Yes, I've turned the current up to max on that extruder (turn clockwise any farther, and it won't run at all).  Increasing the current helped, but it still stalls at some point.

Now I'm stuck: is the problem with the driver, the motor, the gear reduction, or something else I'm not thinking of?

Milo

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Re: Extruder Stalling Problems
« Reply #1 on: September 11, 2013, 12:57:59 PM »
This sounds exactly like the problem I've encountered since I switched to DiamondAge blue tint PLA.
I recorded a short video showing what is happening on the gear's end.
www.youtube.com/watch?v=7Yz6zi5i8PE

I don't think it was happening before I switched filament and I've tried upping temperatures, thinking maybe it was just too much back pressure, but that didn't help.
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whosawhatsis

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Re: Extruder Stalling Problems
« Reply #2 on: September 11, 2013, 10:11:18 PM »
Are you saying that the drive gear is always at the same position in its rotation (with the setscrew facing the same direction) when it stops turning?

ccox

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Re: Extruder Stalling Problems
« Reply #3 on: September 12, 2013, 02:41:08 AM »
Yes, when it stalls, the drive gear stops moving and the set screw stays in the same position.  At that time, the motor/gear reduction makes a grinding sound.
With the lock lever disengaged, it doesn't stall and continues to rotate (but doesn't feed filament so well).  And with the lock disengaged, I can gently push the filament to get extrusion - so it's not a clog.


The other extruder (with the same filament) works perfectly, keeps moving and never makes grinding sounds.

whosawhatsis

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Re: Extruder Stalling Problems
« Reply #4 on: September 14, 2013, 08:27:11 PM »
You're missing the point of my question. What I'm trying to ask is if the motor stalls with the gear in the same position each time, not whether it remains in the same position while it is stalled.

ccox

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Re: Extruder Stalling Problems
« Reply #5 on: September 15, 2013, 05:34:34 AM »
It does not stop in the same place each time.  But it seems to turn better with the lock lever unlocked.
And sometimes it won't even turn with the lock level unlocked.  (like right now - I'll try to post a video later)

I should also note that it is inconsistent - I was able to print for about 20 minutes today before it started stalling again.  But sometimes it stalls almost immediately.  It does not seem to be temperature related.

Each time it stops, I can still push filament through by hand (when unlocked, of course).

I think that means I'm looking at motor or driver issues.
« Last Edit: September 15, 2013, 05:38:05 AM by ccox »

whosawhatsis

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Re: Extruder Stalling Problems
« Reply #6 on: September 18, 2013, 07:33:08 PM »
Sounds that way. Have you tried swapping the driver with one of the others? Be sure to do this while the machine is powered-down.

ccox

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Re: Extruder Stalling Problems
« Reply #7 on: September 21, 2013, 05:04:37 AM »
Results don't make a lot of sense.

Swapping the drivers, the first extruder printed for about 15 minutes, then started stalling and sometimes going in reverse of what it should have been doing - but it wasn't as noisy and bad as before.
Swapping the drivers back (after being powered down for 5 minutes), the first extruder stalls from the start.

So it might be a heat/time related problem with the motor.
And the driver is definitely not right.
I'm starting to think that my first 2 minute print on this extruder was just luck.
And I'm really hoping it isn't something with the X3 board.

Good news is that the second extruder, with it's original driver, is working beautifully.
« Last Edit: September 21, 2013, 06:14:39 AM by ccox »

ccox

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Re: Extruder Stalling Problems
« Reply #8 on: September 21, 2013, 06:47:30 AM »
Interesting.
On the bad extruder motor, one side of the coils measures 4.2 ohms, and the other side measures 3.4 ohms.
The working extruder motor measures 4.1 and 4.2 ohms (DMM only reads down to 0.1 ohm, so that's within error).

Yes, I let everything cool down and disconnected them from the drivers...

Ah, even more interesting, just moving the filament or pressing on the bad extruder motor will change the lower coil resistance (between 3.8 and 3.0).
Moving the wiring harnesses does nothing to the bad coil.
Moving the wiring harnesses, filament and motor does nothing to the good coil.
The only good news is that the bad coil does not appear to be connected to the case.

So the bad extruder motor has an internal short in one coil that is mechanically (and most likely temperature) affected.
Odds are pretty good that trying to drive this has messed up the driver.

Dicey

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Re: Extruder Stalling Problems
« Reply #9 on: September 24, 2013, 06:04:36 PM »
I am also getting the same issue. Using Diamond Age PLA, Sapphire. I've had to result to stopping and clearing the head every few layers on a long run otherwise it will stall like in Milo's video. I've tried during a large extruder retract between layers hoping it might clear it up. But it seems the only thing that consistently fixes the issue is just manually pushing material through so that the hobbed gear can get a new length of filament to bite into. Really hoping this gets resolved as I'd like to be able to leave the machine running overnight.

whosawhatsis

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Re: Extruder Stalling Problems
« Reply #10 on: September 25, 2013, 12:30:49 AM »
What temperature are you running the Diamond Age filament at? Diamond Age filament is a different formula, and probably needs a lower temperature. We had a temperature for it with the previous extruder, but the new one needs different temperatures for some materials, and we haven't had a chance to do much testing with it since the new printbl batch (finally) came in.

whosawhatsis

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Re: Extruder Stalling Problems
« Reply #11 on: September 25, 2013, 12:33:42 AM »
Ccox, sounds like the motor and driver are bad. Send me an email to rich@deezmaker.com with your shipping info to arrange a replacement.

Dicey

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Re: Extruder Stalling Problems
« Reply #12 on: September 25, 2013, 04:13:44 PM »
I'm running it at about 190C per what I've seen as a recomendation.

whosawhatsis

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Re: Extruder Stalling Problems
« Reply #13 on: September 25, 2013, 07:10:49 PM »
Our old extruders ran Diamond Age PLA pretty nicely at 185-190C, but the new one has a shorter hot zone for better flow control, which has the side effect of requiring higher temperatures. 200-210C will probably work better.

Dicey

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Re: Extruder Stalling Problems
« Reply #14 on: September 25, 2013, 07:48:23 PM »
I've run it up to 210C before, but that still doesn't resolve the filament stripping.

 

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