Extruder "stuttering" when printing raft


#21

Thank you for your replies. I can give a short update to my problem.

After I wrote my last post, I sliced and saved my model again, cleaned the extruder wheel, the build plate and did every possible maintenance. I assembled the extruder stepper again and tried to print my model. To my surprise it seemed to work at this point.

After approx. 6 hours of printing my problem was back. While stuttering I checked that the roll is spinning easy, I twisted the cable again, everything without effect. I even additionally pushed the filament by hand, but the extruder did not stop stuttering at some points. The only thing I recognized was, that the extruder was quite hot.

Is it possible that there occur problems with single phases of the stepper due to increasing resistance because of the heat?


#22

Hi Laurent,

Thank you for your hint. Unfortunately I think, that the bed level is not the reason. I had a maximum difference of +0.1 at the center. And when my problem occured again, the print was already 4-5cm high. 😉

Luckily it is the printer at work and not my own M200. :slight_smile:

Oliver


#23

Indeed, it can't be that.

About heat, my extruder stepper motor and the extruder itself become hot during the print, sometimes more than 60°C. If hotter, around 80°C, then it is just to high for the stepper motor and it would be damaged. Moreover, other users experienced similar issues as yours and solved them using a cooling system, mounted on the extruder.


#24

*Deleted* due to reading comprehension problems :wub: on my part.


#25

Thank you! I guess I will either give the cooling system a try or buy a new extruder stepper. :wink:

Sorry for the reading comprehension issues, but english is not my mother tongue, so it may be hard to understand at some points.


#26

Thank you for your replies. I can give a short update to my problem.

After I wrote my last post, I sliced and saved my model again, cleaned the extruder wheel, the build plate and did every possible maintenance. I assembled the extruder stepper again and tried to print my model. To my surprise it seemed to work at this point.

After approx. 6 hours of printing my problem was back. While stuttering I checked that the roll is spinning easy, I twisted the cable again, everything without effect. I even additionally pushed the filament by hand, but the extruder did not stop stuttering at some points. The only thing I recognized was, that the extruder was quite hot.

Is it possible that there occur problems with single phases of the stepper due to increasing resistance because of the heat?

You might want to check if heater and thermocouple are OK/tightly screwed. The tiny screws holding them in the heatblock tend to get loose every now and then. They are somewhat hidden, so it's an easy to miss problem. Try pulling (very gently) them out of their sockets by their wires. If they move, retighten the screws - again, gently - the thermocouple is especially sensitive.

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#27

You might want to check if heater and thermocouple are OK/tightly screwed. The tiny screws holding them in the heatblock tend to get loose every now and then. They are somewhat hidden, so it's an easy to miss problem. Try pulling (very gently) them out of their sockets by their wires. If they move, retighten the screws - again, gently - the thermocouple is especially sensitive.

attachicon.gifIMG_4742.JPG

I will also pay attention on this in the future. For now it´s also not the reason, because I did tighten them, when i assembled the hot end after cleaning.

I guess I will check if it prints well with Z-Hips on monday, because it did before. The problems started with Z-Ultrat spool. But it was not a new one and also worked fine for some prints before.


#28

I have this same skipping issue too. I cleaned the hotend and nozzle pretty well (at least I think) so I assume both are heating up to the proper temperature. I don't have a thermometer to measure the hotend and nozzle to check, yet.

Very interesting about the temperature of the stepper motor...mine is warm as well. Any one know the recommended operating temp of those suckers? Anyways, when I push the filament going into the extruder, it is fine.


#29

I have this same skipping issue too. I cleaned the hotend and nozzle pretty well (at least I think) so I assume both are heating up to the proper temperature. I don't have a thermometer to measure the hotend and nozzle to check, yet.

Very interesting about the temperature of the stepper motor...mine is warm as well. Any one know the recommended operating temp of those suckers? Anyways, when I push the filament going into the extruder, it is fine.

It's normal for the motor to be warm, around 50ºC. Steppers generate more heat when sitting idle and "locked" than when turning.


#30

I also wanted to quickly state that my extrudder skipping also occurs in the air as well (ie when you are loading a new filament). So there is another point for air-skipping. 

The best example I have of this is when I choose the "load a new filament" option twice in a row (in air) and it still studders on the second cycle. I will try and post a video maybe...? I am pretty new to the forum so I don't quite know if I can do that


#31

I also wanted to quickly state that my extrudder skipping also occurs in the air as well (ie when you are loading a new filament). So there is another point for air-skipping. 

The best example I have of this is when I choose the "load a new filament" option twice in a row (in air) and it still studders on the second cycle. I will try and post a video maybe...? I am pretty new to the forum so I don't quite know if I can do that

Well a video is always a good idea, many foreign language writers here, confusion with descriptions does happen often.

Stuttering I do understand as an extruder gear that moves back and forth (or left and right) and this is most probably related to a broken ribbon cable!

The mods for cooling the extruder gear or filament path help prevent extrusion stops that are caused by pre heated filament loosing grip at the gear. this happens without any noticeable clicking on my machine (not anymore after the mod).

Clicking is caused by filament not getting thru the extruder for several reasons and is very noticeable (it just clicks at the extruder).

The OP was about stuttering, you talk about skipping now, who could tell what it is?


#32

"Clicking", "stuttering", and "skipping" are usually different words for the same thing, caused by the motor having insufficient torque to turn its shaft a complete step. Usually happens around twice per second and produces a distinct "clunk" or click. If it's more like a rapid "buzz", i.e. really fast stutter, then it's more likely to be an electrical issue (bad connection) than a mechanical blockage.

"Slipping" is a different issue, when the toothed wheel (feed gear) cannot grip the filament.

It's possible for the two issues to result from the same cause, e.g. blocked nozzle. Whether the filament will slip in the gear before the motor clicks depends on filament type etc.


#33

"Clicking", "stuttering", and "skipping" are different words for the same thing, caused by the motor having insufficient torque to turn its shaft a complete step.

I have a different opinion on this, same as with warping and shrinking for what I told being not the same but one causing the other.


#34

I have a different opinion on this, same as with warping and shrinking for what I told being not the same but one causing the other.

True, shrinkage is what causes warping! But stuttering does not cause clicking, or vice-versa :) Stuttering and clicking are two words for a specific symptomatic thing that happens, caused by mechanical blockage or electrical issue.


#35

True, shrinkage is what causes warping! But stuttering does not cause clicking, or vice-versa :) Stuttering and clicking are two words for a specific symptomatic thing that happens, caused by mechanical blockage or electrical issue.

We're together at the first issue already.  :)

And yes, Stuttering does not cause clicking, but no they are not the same in my opinion. Could be related to different understanding of the words in our languages.

Clicking is caused by the gear loosing the filament grip because of something else blocks further transportation of the filament thru the hot end.

This creates a clicking sound for every loose of tension like a guitar string is actuated.

A stuttering extruder just moves the gear left - right - left - right...

Just a visual thing, no clicking happens because filament moves with the gear until nagged off.


#36

Clicking is caused by the gear loosing the filament grip because of something else blocks further transportation of the filament thru the hot end.

This creates a clicking sound for every loose of tension like a guitar string is actuated.

Yeah, to clarify: I am getting clicking. The gear is not maintaining a grip on the filament while trying to push it through the hotend. I'm sorry for the confusion. I will probably grab some extra nozzles and see some better results. 


#37

Yeah, to clarify: I am getting clicking. The gear is not maintaining a grip on the filament while trying to push it through the hotend. I'm sorry for the confusion. I will probably grab some extra nozzles and see some better results. 

First try the easiest reason for that: Check and probably clean the gear!

There is a support document that shows how to do it.

If the gear is clean, change or clean nozzle and try again with Z-ABS, probably different spool, just to be sure.


#38

Yeah, to clarify: I am getting clicking. The gear is not maintaining a grip on the filament while trying to push it through the hotend. I'm sorry for the confusion. I will probably grab some extra nozzles and see some better results. 

So you're saying that when the click happens, the motor rotates forward (clockwise)?!? I don't think I've ever seen that - it happens so quickly that it's difficult to tell, but I've always thought it goes backwards, because the motor cannot complete its step. I will try to find time to take some high-speed video.

If the gear "loses its grip" on the filament, it pretty much has to mean that the filament gets stripped by the gear, which results in a small arc cut out of the filament and the motor turning with no clicking and no filament movement.


#39

So you're saying that when the click happens, the motor rotates forward (clockwise)?!? I don't think I've ever seen that - it happens so quickly that it's difficult to tell, but I've always thought it goes backwards, because the motor cannot complete its step. I will try to find time to take some high-speed video.

If the gear "loses its grip" on the filament, it pretty much has to mean that the filament gets stripped by the gear, which results in a small arc cut out of the filament and the motor turning with no clicking and no filament movement.

Well, probably your'e right here, it happens quick, maybe some more precise description / discussion is needed. :)

That what I call stuttering (just I) happens without force applied to the filament (e.g. no force from a blocked nozzle that prevents filament forward).

Just the extruders gear is moving between both directions and the filament also.

Clicking is a sound caused by filament or gear (or both) getting over a certain point where the extruder cannot hold the tension on trying to forward the filament.

Because it's happening quickly I cannot tell if it is caused by the filament slipping back from the gear, the gear getting some backlash or just the extruder recognizing the tension and stepping back to prevent damage (some printer have this, not the M200 i think).


#40

Yeah, I agree with both of you guys. Once I do a cleaning, I will take some video and report back.