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PRUSA edition heat break easily jam/clog with PLA  

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bobstro
(@bobstro)
Illustrious Member
RE: PRUSA edition heat break easily jam/clog with PLA
Posted by: Czaro

[...] Performing all the steps in accordance with the instructions and applying thermal paste only for one end of heat break I managed to finish my print without any problems.

[...] I recommend replacing this paste whenever there are clogging problems appear again.

We had a similar spate of "heat creep" and "extruder clicking" posts last year as many parts of the world moved into ever-hotter summers. There was a huge spike last year after the Prusa Lack enclosure blog entry was published in April and happy new owners tried using them in hotter months. A bunch of issues have been linked:

  • General "extruder motor heat".
  • Over-zealous speeds exceeding maximum volumetric rate of E3D V6 hotend, causing skips & jams.
  • Over-zealous use of enclosures to print low-temp PLA without proper cooling.
  • Excessive retractions contributing to extruder motor heat.
  • Increasing temps to increase flow due to extruder motor heat.
  • Excessive extruder idler tension.
  • Poorly aligned filament feed path.
  • Fan covers and gee-gaws interfering with airflow.
  • Filament dust filters jamming filament feed.
  • Filament feed path adding friction and tension.
  • Lack of thermal paste between heat sink and heatbreak. (The big "aha" of Summer 2018.)
  • And lately -- the Prusa custom heatbreak with 2.2mm throat intended to fix MMU issues. (The big "aha" of Summer 2019.)

The causes of excessive heat are varied, and many people have declared victory once they found a solution that worked in their circumstance. The main thing to keep in mind is that the E3D V6 hotend is air cooled, and rated to work in ambient temperatures up to 40C. Exceed that for any one of a myriad of issues, and you are likely to encounter skips and jams. By rectifying one or more of these contributing factors, it's very likely you can get below the threshold at which problems occur. Just keep this list in mind if you encounter the problem again as months get hotter.

In short: Anything that contributes to heat that can't be vented away from the hotend (rated to 40C ambient) impedes air cooling efficiency. There are so many related factors that a problem with any one can cause a variety of feedbacks and problems. I'm willing to put money on the number of these posts declining rapidly once we're out of the summer months. I've compiled some notes on the topic here.

My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Napsal : 28/07/2019 8:52 pm
lindharin se líbí
Protoncek
(@protoncek)
Reputable Member
RE: PRUSA edition heat break easily jam/clog with PLA
Posted by: Tim
Peter -- The heat break jam is totally and completely unrelated to the extruder motor temperature.

Wrong!  It's quite related! Motor temperature becomes quite hot (enough for PLA to get soft), consequently motor shaft becomes hot and as a result both gears which pull filament become hot, too. And when printing is such that very small amount of PLA flows through (it goes forward just a tiny, and back, forward a bit again, back...) PLA gets melted because of that too high temperature. I've had same problems and a fan on the motor eliminated all jams.

Napsal : 29/07/2019 7:10 am
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(@)
Illustrious Member
RE: PRUSA edition heat break easily jam/clog with PLA
Posted by: Protoncek
Posted by: Tim
Peter -- The heat break jam is totally and completely unrelated to the extruder motor temperature.

Wrong!  It's quite related! Motor temperature becomes quite hot (enough for PLA to get soft), consequently motor shaft becomes hot and as a result both gears which pull filament become hot, too. And when printing is such that very small amount of PLA flows through (it goes forward just a tiny, and back, forward a bit again, back...) PLA gets melted because of that too high temperature. I've had same problems and a fan on the motor eliminated all jams.

Totally different failure mechanism ... my motor never gets hot enough to soften PLA yet I had severe lower heat break jams that have 100% vanished with the E3d heat break.  Motor and models and AC settings are the same, no enclosure, either.  Only thing different is the heat break.

And there is a gent currently fighting the heat break jam and he is printing PC ... here's his unloaded filament tip: no evidence of anything happening up at the gears, all the action is at the bottom of the heat break.

lol. 

 

https://forum.prusa3d.com/forum/original-prusa-i3-mk3s-mk3-how-do-i-print-this-printing-help/new-to-polycarbonate-jams/

Napsal : 29/07/2019 7:54 am
Laura F Farrell
(@laura-f-farrell)
Trusted Member
RE: PRUSA edition heat break easily jam/clog with PLA

Yes... Only I have no issues with pure pc filament (in fairness its polymaker PC max) but do experience issues with blended filaments such as colorfabb pa-cf. But not low temperature filaments such as proto pasta metal blends... Its probably the combination of a high hotend temperature and hard blends that brings the issue.

Napsal : 29/07/2019 9:04 am
Feday
(@feday)
Active Member
RE: PRUSA edition heat break easily jam/clog with PLA

 

Totally different failure mechanism ... my motor never gets hot enough to soften PLA yet I had severe lower heat break jams that have 100% vanished with the E3d heat break.  Motor and models and AC settings are the same, no enclosure, either.  Only thing different is the heat break.

And there is a gent currently fighting the heat break jam and he is printing PC ... here's his unloaded filament tip: no evidence of anything happening up at the gears, all the action is at the bottom of the heat break.

I've replaced my heat break with the default one from E3d, even with the recent heatwave my room was 40C and while the extruder motor was very hot to the touch, it never got hot enough to cause any problems. Printing went just fine (there was some increased stringing but that was all).

My conclusion is that  a hot extruder motor won't case these jams.

Napsal : 29/07/2019 9:07 am
Protoncek
(@protoncek)
Reputable Member
RE: PRUSA edition heat break easily jam/clog with PLA
Posted by: Tim
 

Totally different failure mechanism ... my motor never gets hot enough to soften PLA yet I had severe lower heat break jams that have 100% vanished with the E3d heat break.  Motor and models and AC settings are the same, no enclosure, either.  Only thing different is the heat break.

 Well, in this case we have already TWO possible causes for filament jam... that's not good...

What exactly did you change with that one from e3d? Can you give a link?

Napsal : 29/07/2019 9:23 am
Benoit
(@benoit)
Active Member
RE: PRUSA edition heat break easily jam/clog with PLA

In my case the filament has increased diameter after the ptfe tube (it is ~ 2mm if i remember correctly) :

This is a sign that the heat came up from the hotend. Just to be on the safe side, i'll try adding a fan to the extruder motor anyway.

As bobstro mentioned there may be multiple source of jam (by the way, found your notes while searching for a solution, nice work, helped me a lot).

Napsal : 29/07/2019 11:42 am
RAH1
 RAH1
(@rah1)
Estimable Member
RE: PRUSA edition heat break easily jam/clog with PLA
Posted by: Protoncek
Posted by: Tim
 

Totally different failure mechanism ... my motor never gets hot enough to soften PLA yet I had severe lower heat break jams that have 100% vanished with the E3d heat break.  Motor and models and AC settings are the same, no enclosure, either.  Only thing different is the heat break.

 Well, in this case we have already TWO possible causes for filament jam... that's not good...

What exactly did you change with that one from e3d? Can you give a link?

Just read backwards through this topic.  Sources for the replacement are listed several times.  The Prusa heat break in the MK3S is 2.2mm @ the cold end and 2mm hot while the stock E3D heat break is 2mm straight.

RAH

 

I am the inveterate tinkerer. I can tink up most anything.

Napsal : 29/07/2019 11:44 am
bobstro
(@bobstro)
Illustrious Member
RE: PRUSA edition heat break easily jam/clog with PLA
Posted by: newwdles

[...] As bobstro mentioned there may be multiple source of jam (by the way, found your notes while searching for a solution, nice work, helped me a lot).

Glad it helped. As I noted, these issues are not new. What is new is the "aha, it's the heatbreak!" universal solution being applied to all cases this year. Last year it was "aha, we need thermal paste!" universal solution. Either may have helped in many situations.

I'm going to push back on the idea that the extruder motor and PLA softening are unrelated for the reason that softening PLA can increase friction which can cause the extruder motor to work harder. If airflow is not adequate, that's more heat staying in the general vicinity of the extruder, contributing to the feedback problem. If frequent retractions are in use, the non-Newtonian behavior of softening filament can also contribute. "Heat" isn't a quick fix problem. Many factors can contribute.

It's great that people are finding a solution that works in their specific situation, but we should stop suggesting that our hammer is the best tool for every job. Temp-related problems are best countered using a checklist, not just blindly applying one universal fix. Something that works in July temps may not be sufficient on its own for August temps. If my extruder motor is still running hotter than normal, I want to figure out all the reasons and fix those that I can.

My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Napsal : 29/07/2019 2:45 pm
bobstro
(@bobstro)
Illustrious Member
RE: PRUSA edition heat break easily jam/clog with PLA
Posted by: Protoncek
[...] Well, in this case we have already TWO possible causes for filament jam... that's not good...
There are many more than two, and most are not unique to Prusa printers. Spend some time in the Reddit 3D printing groups and you'll see a lot of these same topics come up for other printers.
 
Air cooled hotends in general are going to have issues as temperatures increase. The causes of temperature increases are many. Increased temperatures affect the cooling efficiency of air cooled systems such at the E3D V6 hotend. Softening PLA can cause a variety of symptoms. I'm all for quick fixes, but I do like to look at the problem in a systemic manner. "Getting it to work" is important, but understanding why the problem occurred in the 1st place and what the contributing factors are is much more useful.
 
I wonder if the heatbreak issue is exacerbated by using high de-retract speeds. I've set mine to 25mm/s (based on an excellent article by Michael Hackney) and am able to experiment with retraction speeds without introducing problems. This might explain why some people are able to use the Prusa heatbreak without problems while others suffer from it constantly.
My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Napsal : 29/07/2019 2:55 pm
Nikolai
(@nikolai)
Noble Member
RE: PRUSA edition heat break easily jam/clog with PLA

This thread evolved to "My car is broken and now I found the reason why. In case your car doesn't run anymore here is THE SOLUTION(TM)".

Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram

Napsal : 29/07/2019 5:20 pm
-- a bobstro se líbí
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(@)
Illustrious Member
RE: PRUSA edition heat break easily jam/clog with PLA

Now if we could get a similar thread going about ghosts in the mesh level firmware.  You'd think Prusa would take the time to ensure it worked at least 80% of the time since it is a major selling point for their hardware.  Pretty sure they introduced more errors with the magnetic compensation that doesn't seem to turn off because whoever was coding didn't understand PINDA thermal sensitivity.  You know: that old garbage in - garbage out data collection issue.

But I am ranting ... perhaps I'll need to get out my edn tools and create a real filament sensor that gives users real info... imagine a sensor that - in addition to on-off - monitors filament diameter and feeds that to the firmware for intra-layer extrusion compensation. 

Napsal : 29/07/2019 7:34 pm
Benoit
(@benoit)
Active Member
RE: PRUSA edition heat break easily jam/clog with PLA
Posted by: nikolai.r

This thread evolved to "My car is broken and now I found the reason why. In case your car doesn't run anymore here is THE SOLUTION(TM)".

Don't really see that, just a bunch of people trying to help each other. It's been almost 3 weeks since i'm trying to resolve this clogging issue so i'll take any leads.

I tried to lower the tension on the extruder idler as much as possible to reduce the motor heat, guess i reduced it too much ->  ptfe clogged in a minute. So in my case I don't think the heat from the motor is the culprit

Napsal : 29/07/2019 7:57 pm
Karl
 Karl
(@karl-3)
Active Member
RE: PRUSA edition heat break easily jam/clog with PLA
Posted by: Tim

Now if we could get a similar thread going about ghosts in the mesh level firmware.  You'd think Prusa would take the time to ensure it worked at least 80% of the time since it is a major selling point for their hardware.  Pretty sure they introduced more errors with the magnetic compensation that doesn't seem to turn off because whoever was coding didn't understand PINDA thermal sensitivity.  You know: that old garbage in - garbage out data collection issue.

But I am ranting ... perhaps I'll need to get out my edn tools and create a real filament sensor that gives users real info... imagine a sensor that - in addition to on-off - monitors filament diameter and feeds that to the firmware for intra-layer extrusion compensation. 

I WOULD PAY MUCHO MONIES FOR SUCH A THING ! then prusa will copy it and everyone will think they invented it

 

This post was modified před 5 years by Karl
Napsal : 29/07/2019 8:21 pm
bobstro
(@bobstro)
Illustrious Member
RE: PRUSA edition heat break easily jam/clog with PLA
Posted by: Tim

Now if we could get a similar thread going about ghosts in the mesh level firmware.  [...]

What are the issues? I've seen discussions where it's not sufficient to overcome bad warping, but I'm doing fine with 0.4mm deviations. Have put off plans to do nylock leveling it's been so good with 7x7 enabled. 

I'm still stubbornly doing the PINDA warmup for each print, but more to warm the bed at this point. Is that a factor?

My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Napsal : 29/07/2019 9:28 pm
bobstro
(@bobstro)
Illustrious Member
RE: PRUSA edition heat break easily jam/clog with PLA
Posted by: karldavy149
[...] Prusa will copy it and everyone will think they invented it

Are you subscribed to DPT's YouTube channel by any chance?

That's how open source hardware works. Why do you think so many clones call themselves i3 or Prusa designs? Have you read up on JP's involvement in the reprap movement? He readily credits others but has also contributed a lot himself. Producing open source hardware does not require a vow of poverty. You're allowed to make money. 

My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Napsal : 29/07/2019 9:32 pm
CybrSage se líbí
Benoit
(@benoit)
Active Member
RE: PRUSA edition heat break easily jam/clog with PLA

Guys please stay in the subject, people come here because they need a solution to their clog, not to read debates about open source hardware or mesh bed leveling bugs.

Napsal : 30/07/2019 7:35 am
33edc se líbí
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(@)
Illustrious Member
RE: PRUSA edition heat break easily jam/clog with PLA
Posted by: newwdles

Guys please stay in the subject, people come here because they need a solution to their clog, not to read debates about open source hardware or mesh bed leveling bugs.

It is all interrelated.  A firmware issue in bed leveling can cause some of the problems being experienced here.

Napsal : 30/07/2019 8:14 am
Karl
 Karl
(@karl-3)
Active Member
RE: PRUSA edition heat break easily jam/clog with PLA
Posted by: bobstro
Posted by: karldavy149
[...] Prusa will copy it and everyone will think they invented it

Are you subscribed to DPT's YouTube channel by any chance?

That's how open source hardware works. Why do you think so many clones call themselves i3 or Prusa designs? Have you read up on JP's involvement in the reprap movement? He readily credits others but has also contributed a lot himself. Producing open source hardware does not require a vow of poverty. You're allowed to make money. 

i know he credits others but that doesnt stop the fanbois thinking he invented it ... and agree what he does, does push the boundaries of 3d printing he takes other peoples ideas mixes and blends enhances them into his own product... that is also one of the reasons we have the "clicking extruder" they try to much to soon and then other people copy the idea but if you ask me the prusa as more so as the potential for more things to go wrong and for many of us posting on this thread and many others scattered across 3d printing forums that is the case i3 mega flawless printing with tmc 2130 drivers installed total cost 1/3 of prusa ender 3 flawless printing with mainboard and driver upgrade total cost 1/3 of prusa chiron flawless printing with driver updates total cost 1/2 prusa but double the print size u see where im going with this ! they are "clones" with less but u get more because u dont have the hassle of all these systems and hardware communicating with each other that create potential issues

 

 

This post was modified před 5 years by Karl
Napsal : 30/07/2019 12:45 pm
Nikolai
(@nikolai)
Noble Member
RE: PRUSA edition heat break easily jam/clog with PLA

@karldavy149 Your text block is very hard to read. Feel free to open a new "rant" thread or use existing one. Would be nice to stay on topic here.

Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram

Napsal : 30/07/2019 2:02 pm
CybrSage se líbí
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