Filament continually clogging and getting stuck in extruder gears  

Re: Filament stuck and no idea how to remove it

Update: took apart the heater assembly and was able to remove the clog (I had to cut a little bit of the damaged PTFE tube but the filament still is able to load correctly). However, now when I try to calibrate my printer, the Z axis goes way too far down. During XYZ calibration the nozzle catches the paper and I power off as instructed if that is the case. When I tried just the Z calibration it was pressing so far down it was damaging the print bed. I've tried XYZ calibration twice and every time when it gets down to the paper and it's supposed to go the next calibration point it just keeps pressing harder and harder until I have to power off as it's pressing hard enough to damage something eventually, rubbing right through the paper.

Im curious where I should go from this point since my usual calibrations are now failing since removing the jam

EDIT: I followed the manual and lowered my Pinda sensor (this is the first time I've ever had to do this). Even though the bottom of the sensor doesn't look completely laying horizontal it seems to have done the trick. My only problem now is that since I've resumed printing I have had another occurrence of the filament getting wrapped around the extruder gears. Still printing with PLA (another color and brand from my initial blockage so I'm guessing my issue is more with blockage than specific filament problems). I'm feeling like this is caused by some sort of blockage that's making the filament back up. I've used an acupuncture needle to clear the nozzle when I initially took apart the heating element to remove the first clog, and I made sure there weren't any stray bits of filament remaining.

I have since loosened the screws with springs on them that hold the extruder gear hatch shut to see if that makes a difference. If anyone has had this issue of filament wrapping around the extruder gears please let me know how you solved it as I've just gotten 3 orders for multi-part products that I print and I don't want to have this issue re-occur when time is a factor.

EDIT: happened for a third time about 30 minutes into a print just now, silver prusa PLA backed up, caught in gears and stopped extruding during print. Picture is attached below

Thank you for any advice.

Re: Filament continually clogging and getting stuck in extruder gears

Austin,
I had the exact same problem, with the same silver PLA that came with the printer.
I was able to solve it loosening the spring loaded screws. I unscrew them to obtain the minimum possible force on the pulley.

Unluckly the filament sensor now does not work any more (N/A on the LCD ) , so be careful when trying to pull the stuck filament out!!

Good luck!

Re: Filament continually clogging and getting stuck in extruder gears

What version of the firmware are you using?

I'm seeing a lot of problems appearing in the forum that seems to indicate that the filament is getting soft at the gears.

See this thread for a lot of examples:

https://shop.prusa3d.com/forum/others-archive--f66/clicking-printhead-filament-stuck--t14916.html

Re: Filament continually clogging and getting stuck in extruder gears

Some of the symptoms are little like the ones I have had. I have had the nozzle hit the bed hard under the first calibration , adjusted the probe and got it running but have to adjust Z -1,25mm (have printed around 2-3weeks like that). Then I decided to adjust the probe so the Z adjustment was under the -1mm as it is described by Prusa. And again it hit the bed HARD , adjusted the probe a little and got around Z-0,88. But now i have trouble with clicking extruder.
I am starting to think that it might be something with the flat nozzle / bend heat break, maybe the filament is not allow to run as freely as it use to or a heat lost somewhere so the extruder motor try to push the filament out of a “cold” nozzle. (still need to check if the heater is lose in the heat block)

I have ordered new nozzle, heat break and PTFE tube, HOPE this work…

Re: Filament continually clogging and getting stuck in extruder gears

You could try my fix for this issue here: https://www.thingiverse.com/thing:2867249

I had the exact same issue so I reduced the spacing between the tube and bondtech gears to create a direct path. I also added heatsinks to the motor to try and remove some of the heat upstream.

Re: Filament continually clogging and getting stuck in extruder gears

Hi @zcubed,

Thanks for your files.

I printed and installed them and it seems to have improved the success rate of my prints but not solved the issue.

In case anyone stumbles here with the same problem I'm trying to keep a log of the issue in this forum thread:
https://shop.prusa3d.com/forum/others-archive--f66/clicking-printhead-filament-stuck--t14916.html

Re: Filament continually clogging and getting stuck in extruder gears

The heat break is bend.. I hope this is the reason 💡

Re: Filament continually clogging and getting stuck in extruder gears

Maybe i am little to fast on the trigger .. but I have made the first print without “clicking” (at normal speed and temperature) after I have replaced nozzle, heat brake and PTFE tube 🙂

Re: Filament continually clogging and getting stuck in extruder gears

Maybe i am little to fast on the trigger .. but I have made the first print without “clicking” (at normal speed and temperature) after I have replaced nozzle, heat brake and PTFE tube 🙂

WHOA.

I've been wondering if the heat break could be the cause of your guys issues, but I don't like saying "go spend money, when I'm just making guesses in the dark.".

Whoa.

I replaced mine becuase it was jamming up... and mine is not bent.

I was getting "clogs" that were not the nozzle, replaced basically everything the filament touched except the heatbreak, to no fix, so when I replaced the heatbreak it fixed it.

I was discussing the heatbreak with someone on the forums, and it seems like the MMU/MK3 heatbreak is... flawed.

Re: Filament continually clogging and getting stuck in extruder gears

But if it is flawed, why are more of us (including myself) not having any issues? I've got 720+ hours of print time on mine with 270 degree PETG, PLA, and TPU. No issues- never a clog.

Re: Filament continually clogging and getting stuck in extruder gears

But if it is flawed, why are more of us (including myself) not having any issues? I've got 720+ hours of print time on mine with 270 degree PETG, PLA, and TPU. No issues- never a clog.

I'm not sure. Coming from CNC machining background, I would guess there's something possibly up with the original machining. I do not have access to my old "lab" else I would cut my old heatbreak in half to investigate it myself. I will be asking E3D if they will investigate it, and send me the results. (I will meet the E3D guys @ ERRF2018)

My understanding of the MMU/MK3 heatbreak, (and I visually confirmed this looking into it) There is a "step" on the "top" of the heatbreak. I am unable to measure the ID at any of these points, without cutting it in half, and I do NOT have the proper equipment for doing it "cleanly", so I'm not going to do it.

But it goes from the 4mm ID for the PTFE tube, down to ~2.1 or 2.2mm. Eyeballing this here, so forgive my lack of accuracy. 😛 which goes from the PTFE tube, down to the "top" of the neck. (I think) It is hard to gauge distance looking down a ~2.1mm hole. There is a "step" that goes down to 1.9mm. This is specced by Prusa, and is NORMALLY ~2mm. In fact, I think this is the same diameter from top to bottom on a "normal" E3D V6 heatbreak. I am unsure on this though, as I do not own one to look at!

Anyway. I am unable to feed filament through my MMU/Mk3 E3D heatbreak "freely" as in, the 1.72-1.73mm filament is "touching" the heatbreak. You might say "Oh but yeah, that's because your filament isn't straight!"
My 1.9mm ID, Capricorn PTFE tube, *DOES* slide freely over my filament.

There is something smaller than 1.9mm ID in my hot end. In fact, I would go as far as to say, it could be a damaged drill, causing "micro burrs" on the ID. These micro-burrs are less relevant when new, however through "normal use" PLA will begin to carbonize in it. I specifically encountered my problem after printing with ABS rather hot. Almost as if the ABS broke my heat break. I know, you are gonna say "There's ABS stuck in there silly, that's what happend!" Yes. Let's play that game. That's why ABS jammed in there too!
I think the issue has SOMETHING to do with carbonization of the PLA. This really only happens at ABS/PC/Nylon temps though.

Feel free to say "It's not the heatbreak". But there's apparently a *LOT* of people "fixing" their mk2 MMUs, with "their original, old, MK2" heatbreak.
And honestly, the "last" time I tried to "manually" push filament through my hot end, was nearly impossible, it felt like there was a "jam". (eg, the nozzle was 75% clogged) My guess is that was the "heatbreak" grabbing the filament as it went through it.

I'm not realling blaming E3D, as it's a "non-standard" heatbreak. But the fact of the matter is, as big of a problem as the MK3's PSU is... (240watt heat bed+40watt nozzle, on a 240watt PSU anyone?)

You saying "I've printed 750 hours with no problems from my heatbreak" is like me saying "I've printed 7kg of filament, and who know how many hours, and my PSU still works like a charm. 95% of us have not had any PSU issues. Why are YOU having PSU issues, and the MAJORITY are not?"

Have you noticed how many people have "jams" and their "extruder motor runs hot?"

We are talking a HIGHER percentage of the "community" than the PSU problem.

My extruder did NOT run hot, until I started getting "jams". As long as I could do a print, with no "extended slow-downs" I could print ALL day. My motor was just getting hotter, and hotter though.

I always wondered "what are these guys doing to get their extruder so hot?"

Now I know. It also explains filament out the side of the extruder. It has NOTHING to do with the hot-end temp, or infill speed, they are having a quazi-jam in the heatbreak, and it's making their extruder motor STUPID hot, which is softening the plastic enough to cause MAJOR problem.

Re: Filament continually clogging and getting stuck in extruder gears

One thing I noticed when I pulled my hotend a part was that the heatsink was very lose on the heat break.
I'm wondering if the heatbreak gets so hot on the first layer and melt some filament in the heatbreak and then when the print fan starts on second layer it maybe cool down the heat break a little so the filament gets colder and don't flow as well. I know that this theory don't work on ABS as it usually does not have print fan on 😁

Re: Filament continually clogging and getting stuck in extruder gears

I'm not realling blaming E3D, as it's a "non-standard" heatbreak. But the fact of the matter is, as big of a problem as the MK3's PSU is... (240watt heat bed+40watt nozzle, on a 240watt PSU anyone?)

I‘m puzzled. You say the heatbreak in the MK3 is not a genuine E3D V6 heatbrake? What is it, a custom design made by E3D for Prusa? Or some 3rd party heatbrake?

Cheers

Pete

Re: Filament continually clogging and getting stuck in extruder gears

I‘m puzzled. You say the heatbreak in the MK3 is not a genuine E3D V6 heatbrake? What is it, a custom design made by E3D for Prusa? Or some 3rd party heatbrake?

Cheers

Pete

Semi-Custom fabricated by E3D.

https://wiki.e3d-online.com/images/0/09/V6-175-BREAK.pdf

That is the "typical" E3D V6 heat break. 100% stock. This would be FINE.

The "potential" design flaw on the Prusa MMU version (which is what the MK3 has)

Looking at that image of the Heat break, Just above the "neck" there is a "step" and from the "neck" down, is 1.9mm.

So it's 2.0mm ABOVE the "neck" and
1.9mm from the neck down.

This allows a VERY small "lip" on the filament, to cause a *JAM*

I think it also can get "carbon buildup" and kinda... "catches" filament. (or even burrs) Making it "harder" to push into the nozzle. (causing high temps on the extruder motor, and clicking sounds)
It also will cause under-extrusion. Basically it's a jam. Kinda.

This is a image of the Micro Swiss heatbreak. If you notice theirs is "smaller" towards the top of the heatbreak, and there's a "step" on the inside getting LARGER going towards the bottom.

This prevents the filament from ever "jamming" on the "forward" motion, and as long as the filament is "hot" you can always retract it over that step. (And if it's not, you can always push it forward to melt/heat it, given there's no step between the filament, and the heat)

My understanding of the MMU/Mk3 version, is they are the EXACT opposite concept, of the SwissTech.

Basically
Looking down hole from TOP of heat break, on E3D MMU one, you can see a "step" towards the bottom. This is what I think is causing the issues.

Looking UP the heatbreak, on the Micro Swiss, you can see a "step" towards the bottom. (the side you are looking in) They claim this makes it better.

Re: Filament continually clogging and getting stuck in extruder gears

Just to update everyone I ended up ordering a replacement v6 MK3 hotend from Prusa, and I noticed 2 differences in the one they shipped me and the one that originally came with my printer:

1: The wires for the Thermistor have a brass tubing extending from where they connect to the heat block. In the first hotend I received the wires just stuck directly into the hole where the thermistor is with nothing extending outside the hole. I'm thankful for this as when trying to repair my first hotend those wires are unprotected and their cloth-like insulation pulled back, exposing bare wiring and causing a short and several sparks, destroying the thermistor of my first hotend. I'm assuming this is some sort of protective barrel but it may be a part incorporated into the thermistor itself.

2: The heat break is red, while previously it was the natural silver color of the metal. I'm not sure what the purpose of the red coating is, but it works and I don't want to take it apart to find out exactly how that coating is applied

I ended up getting jams in the extruder again (like the ones I originally posted about) over the past few days but I just replaced the nozzle, (after a whole lot of effort removing the nozzle it shipped with, which was vastly over-tightened, just like the first shipped nozzle on my old hotend) and things seem to be working smoothly again.

Re: Filament continually clogging and getting stuck in extruder gears

But if it is flawed, why are more of us (including myself) not having any issues? I've got 720+ hours of print time on mine with 270 degree PETG, PLA, and TPU. No issues- never a clog.

I'm not sure. Coming from CNC machining background, I would guess there's something possibly up with the original machining. I do not have access to my old "lab" else I would cut my old heatbreak in half to investigate it myself. I will be asking E3D if they will investigate it, and send me the results. (I will meet the E3D guys @ ERRF2018)

My understanding of the MMU/MK3 heatbreak, (and I visually confirmed this looking into it) There is a "step" on the "top" of the heatbreak. I am unable to measure the ID at any of these points, without cutting it in half, and I do NOT have the proper equipment for doing it "cleanly", so I'm not going to do it.

But it goes from the 4mm ID for the PTFE tube, down to ~2.1 or 2.2mm. Eyeballing this here, so forgive my lack of accuracy. 😛 which goes from the PTFE tube, down to the "top" of the neck. (I think) It is hard to gauge distance looking down a ~2.1mm hole. There is a "step" that goes down to 1.9mm. This is specced by Prusa, and is NORMALLY ~2mm. In fact, I think this is the same diameter from top to bottom on a "normal" E3D V6 heatbreak. I am unsure on this though, as I do not own one to look at!

Anyway. I am unable to feed filament through my MMU/Mk3 E3D heatbreak "freely" as in, the 1.72-1.73mm filament is "touching" the heatbreak. You might say "Oh but yeah, that's because your filament isn't straight!"
My 1.9mm ID, Capricorn PTFE tube, *DOES* slide freely over my filament.

There is something smaller than 1.9mm ID in my hot end. In fact, I would go as far as to say, it could be a damaged drill, causing "micro burrs" on the ID. These micro-burrs are less relevant when new, however through "normal use" PLA will begin to carbonize in it. I specifically encountered my problem after printing with ABS rather hot. Almost as if the ABS broke my heat break. I know, you are gonna say "There's ABS stuck in there silly, that's what happend!" Yes. Let's play that game. That's why ABS jammed in there too!
I think the issue has SOMETHING to do with carbonization of the PLA. This really only happens at ABS/PC/Nylon temps though.

Feel free to say "It's not the heatbreak". But there's apparently a *LOT* of people "fixing" their mk2 MMUs, with "their original, old, MK2" heatbreak.
And honestly, the "last" time I tried to "manually" push filament through my hot end, was nearly impossible, it felt like there was a "jam". (eg, the nozzle was 75% clogged) My guess is that was the "heatbreak" grabbing the filament as it went through it.

I'm not realling blaming E3D, as it's a "non-standard" heatbreak. But the fact of the matter is, as big of a problem as the MK3's PSU is... (240watt heat bed+40watt nozzle, on a 240watt PSU anyone?)

You saying "I've printed 750 hours with no problems from my heatbreak" is like me saying "I've printed 7kg of filament, and who know how many hours, and my PSU still works like a charm. 95% of us have not had any PSU issues. Why are YOU having PSU issues, and the MAJORITY are not?"

Have you noticed how many people have "jams" and their "extruder motor runs hot?"

We are talking a HIGHER percentage of the "community" than the PSU problem.

My extruder did NOT run hot, until I started getting "jams". As long as I could do a print, with no "extended slow-downs" I could print ALL day. My motor was just getting hotter, and hotter though.

I always wondered "what are these guys doing to get their extruder so hot?"

Now I know. It also explains filament out the side of the extruder. It has NOTHING to do with the hot-end temp, or infill speed, they are having a quazi-jam in the heatbreak, and it's making their extruder motor STUPID hot, which is softening the plastic enough to cause MAJOR problem.

I think your theory might be right. I just ordered the swiss heatbrake to have a go at it.

Re: Filament continually clogging and getting stuck in extruder gears

Just out of curiosity, has anyone tried replacing the stock PTFE tube that goes from the feeder gears down into the hotend with one made of Capricorn material?

I feel this would benefit form several effects.

1. The material has a natural(synthetic lol) lubricant that would allow for the material to slide better/easier in the tube into/through the heatbreak, and hotend.
2. The ID is smaller, and almost the exact size of your filament so it will have less of a chance to expand, and/or bind up in the tube (Especially helpful with flexible materials.
3. It has a higher temp range, and would help with the thermal barrier/protection in keeping the heat creep from reaching the filament in this section of the extruder yes?

Anyways, I am planning on doing this when I get mine (eventually lol).

I also plan on making my tube slightly longer, and with more of a ^ cut in it like on the Flexion extruders so that it fits tighter against the extruder gears, and less of a chance for the filament to escape when printing flexible material.

Re: Filament continually clogging and getting stuck in extruder gears

Not a realy scientific video but Joel also has a unit where he gets constant clogs.

Re: Filament continually clogging and getting stuck in extruder gears

Was the OP ever able to solve this to his satisfaction?

I suppose one could insert additional temperature sensors to monitor the temperature in different stages of the heating process. That might help diagnose the problem. It does seem like R&D that end-users shouldn't have to be doing though.

Would a stock E3D V6 fit and function within the Prusa I3 MK3 PETG parts, or would only the customized Prusa E3D V6 fit?