1 Topic by zeograd (edited by zeograd 2015-05-29 14:49:42)

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Topic: [SOLVED] Troubleshooting: stalled motor + motor engine pushed back

Hi,
  I'm still in my first hour(s) of extrusion to clean the pipe.

After a first run of 30minutes of extrusion, I resumed extruding today and the first 30 minutes were ok (180° using provided "cleaning" ABS pellets).

After that, I noticed that the hotend started to "wiggle" left and right slightly (2mm off median position, with a period of 20 seconds or so).
I checked my filastruder more closely at this point, trying to figure out whether it would "run in" and improve over time or not. Some minute later, the motor noise would go in the high pitch range and slowed down and stalled for a short amount of time before resuming.

I then kept my finger on the switch and stare at the motor, trying to find out whether it was a temporary situation or not. But some seconds later, the motor stalled again and the motor support started to move back.
I turned off the motor immediately and let the heater on for a couple extra minutes, to let the pressure off by the nozzle.

Related image gallery : http://imgur.com/a/CkqFQ

As I have seen some users damage their machine by doing the wrong thing and not asking beforehand on the forum, I prefer to ask for advices at this point.

My understanding is that the hotend wiggling was the first symptom and that the motor stalling and support moving back were consequences.
Since the wiggling happened after some time and not immediately, I'd tend to think that the auger + pipe alignment was initially good and that the addition of melted plastic/pellets caused some problems.
So, it might be that the temperature is too low at some point and clogging the pipe, thus impeding the auger movement and later increasing the pressure leading to increased motor load up to its limit (hence stalling).
It might also be a contaminated nozzle, but since I saw plastic out at what I thought a regular rate (not too sure, I was focusing on this) between the stallings, I'd say the nozzle seems free of debris.

What should I do at this point ? Try with higher temp, unmount nozzle for inspection, disassemble and reassemble part or whole of the machine ?

Thanks in advance,
Olivier

2 Reply by elmoret

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Re: [SOLVED] Troubleshooting: stalled motor + motor engine pushed back

The motor being pushed back means you did not follow the portion of the instructions about keeping the thrust bearing compressed during assembly.

Disassemble and re-mount.

Filastruder - the robust, inexpensive filament extruder
E3Dv6 All Metal Hotend - the premier 3D printing hotend

3 Reply by zeograd

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Re: [SOLVED] Troubleshooting: stalled motor + motor engine pushed back

Thanks for your answer.
I hadn't understood the "compressed thrust bearing" properly when assembling it initially (it was compressed when I positioned the main support but the auger could still be pushed further away from the nozzle; now I understand better).

To disassemble my filastruder up to the point where the pipe is cleaned and I can manually move the feedscrew to compress the thrust bearing (step 22 of documentation v1.1), I think I need to apply the nozzle changing procedure first.

But then, would you recommend to extract the still hot plastic manually (with pliers e.g.), by manipulating the feedscrew (once the collar, thrust bearing and spacer are removed, it might be pushed/pulled by hand I imagine) or soaking the whole into acetone and wait for it to dissolve plastic remains ?

Thanks again for your support,
Olivier

4 Reply by elmoret

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Re: [SOLVED] Troubleshooting: stalled motor + motor engine pushed back

Why do you need to remove the nozzle/melted plastic?

Filastruder - the robust, inexpensive filament extruder
E3Dv6 All Metal Hotend - the premier 3D printing hotend

5 Reply by zeograd

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Re: [SOLVED] Troubleshooting: stalled motor + motor engine pushed back

As I have messed the step 22, I wanted to be sure the feedscrew was in its extremum position by sliding it manually as I should have done.
Having melted plastic inside the pipe would prevent me from moving it.

Now, if we can assume that the pressure from operation already pushed the feedscrew in its most extreme position, I only have to reposition the 2 supports to make sure that the engine axis is in line with the feedscrew and the feedscrew can't push back on the engine. In this case, there is no need to remove the nozzle and plastic, of course.

What would you recommend ?

6 Reply by elmoret

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Re: [SOLVED] Troubleshooting: stalled motor + motor engine pushed back

Pressure from the plastic has already bottomed out the thrust bearing.

I recommend disassembly (remove the mounts from the base) and remounting, like I said above. smile

Filastruder - the robust, inexpensive filament extruder
E3Dv6 All Metal Hotend - the premier 3D printing hotend

7 Reply by zeograd

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Re: [SOLVED] Troubleshooting: stalled motor + motor engine pushed back

Understood, thanks for the clarification.

I'll do so and report.

8 Reply by zeograd (edited by zeograd 2015-05-29 13:42:08)

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Re: [SOLVED] Troubleshooting: stalled motor + motor engine pushed back

Indeed, moving the main support away from the engine to account for the feedscrew move when pushed away from the nozzle by the pressure did the trick.

I had to change the washer connecting the motor axis to the feedscrew adaptor. The old one was torn away and probably saved the rest of the machine : http://i.imgur.com/qn64FoY.jpg?1.

I have resumed the cleaning operation for several hours now and this issue looks fixed for me.
Thanks again for your support.

Olivier

PS: is there any way to flag the thread as "solved" ?

9 Reply by elmoret

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Re: [SOLVED] Troubleshooting: stalled motor + motor engine pushed back

Yes, that functionality is by design - it is a mechanical fuse.

I think you can edit the thread title to add [Solved].

Filastruder - the robust, inexpensive filament extruder
E3Dv6 All Metal Hotend - the premier 3D printing hotend