RE: PRUSA edition heat break easily jam/clog with PLA
Couple additional thoughts. You checked the one gear, what about the second one? Does it sit correct on the shaft? Is the shaft still in correct place? Is it rotating freely?
If there are no issues with the gears, I would replace the nozzle if you haven't tried that yet.
I checked this again: it's in the right place (right in the middle) and alignment is ok. I cleaned it multiple times and is rotating freely.
I replaced the nozzle, pfte tube and heatbreak (stock E3D) in one go.
RE: PRUSA edition heat break easily jam/clog with PLA
It's very interesting. I understand that you get some back pressure and you could avoid that with some different slicer settings and/or different heatbreak. But I still place my bet around the gears. Usually they have enough force to eat completely through filament. Instead they are slipping through. There must be either bad contact or not enough pressure (between two gears).
Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram
RE: PRUSA edition heat break easily jam/clog with PLA
It's very interesting. I understand that you get some back pressure and you could avoid that with some different slicer settings and/or different heatbreak. But I still place my bet around the gears. Usually they have enough force to eat completely through filament. Instead they are slipping through. There must be either bad contact or not enough pressure.
The thing is: when I just got the printer I had the same issue with PLA. I then switched to NGEN and never had any issues.
I actually forgot about the problem. Now that I started using PLA again for my CNC I'm building, the problem pops up again. Can't print a thing for the moment.
I'm even wondering if I could fit a 3rd party extruder on my mk3 that doesn't have this problem.
RE: PRUSA edition heat break easily jam/clog with PLA
I would suggest to upgrade it to R3/R4 parts. The air flow was improved and if you have no MMU change the heatbreak like tim suggested. This should improve the PLA printing success a lot.
Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram
RE: PRUSA edition heat break easily jam/clog with PLA
It's very interesting. I understand that you get some back pressure and you could avoid that with some different slicer settings and/or different heatbreak. But I still place my bet around the gears. Usually they have enough force to eat completely through filament. Instead they are slipping through. There must be either bad contact or not enough pressure (between two gears).
Not ruling out filament drive issues. But the filament images have shown clean tooth marks, and an earlier image does show filament ground in half, so it does look like it is being pushed hard enough - at least in prior jams.
I'm thinking there is a heat problem causing the filament to swell in the heat break and it starts rubbing the walls to the point of jamming. Something new after the rebuild, or perhaps an older lingering problem like dust or fan issues. But the old filament images don't show the swelling, fan is at speed, so ... rebuild issue?
Jan - when you look at the old heat break, is there silver grease on the upper threads? And what is your room temp doing today?
And for grins: try printing that part but with nozzle temp set to a more normal 210c.
RE: PRUSA edition heat break easily jam/clog with PLA
look at the end of the day i love prusa and everything they stand for but the mk3 as many design flaws that are even acknowledge ive seen people pass the buck temp retraction settings blah blah blah ... u know if i take a typical gcode that was designed for the mk3s and simply load it up in my direct drive i3 mega s thats basically running stock everything besides the direct drive upgrade i have 0 issues with the same gcode explain to me how a printers that cost me £200 plus the direct drive upgrade as better results than the printer that cost £800 if u ask me prusa is the apple of 3d printers you are getting nothing that the others cant offer but your paying extra for the label and after 20 days + (480 hours) of printing on my prusa i still prefer my ever dependable i3mega by anycubic so much so that when i won a large contract that would require to expand my farm by atleast 10 printers i choose the i3 mega instead of prusa and price had nothign to do with the purchase just reliablility
RE: PRUSA edition heat break easily jam/clog with PLA
look at the end of the day i love prusa and everything they stand for but the mk3 as many design flaws that are even acknowledge ive seen people pass the buck temp retraction settings blah blah blah ... u know if i take a typical gcode that was designed for the mk3s and simply load it up in my direct drive i3 mega s thats basically running stock everything besides the direct drive upgrade i have 0 issues with the same gcode explain to me how a printers that cost me £200 plus the direct drive upgrade as better results than the printer that cost £800 if u ask me prusa is the apple of 3d printers you are getting nothing that the others cant offer but your paying extra for the label and after 20 days + (480 hours) of printing on my prusa i still prefer my ever dependable i3mega by anycubic so much so that when i won a large contract that would require to expand my farm by atleast 10 printers i choose the i3 mega instead of prusa and price had nothign to do with the purchase just reliablility
Well to be honest I'm starting to regret I bought the MK3. I simply can't reliably print PLA with it.
I retried printing at 215/210°C as suggested and my print succeeded. Yay! Until I tried the second print... clicking like hell again!
The strange thing is that the idle gear seems to be skipping back.
I really have no clue anymore what to try next (did the hw swap, tried printing at stock/higher temps, tried 50% speed,...). PLA just does not work.
My latest attempt:
RE: PRUSA edition heat break easily jam/clog with PLA
For what it's worth: did another test. I waited until the printer was completely cooled down. I vented the room, room temperature was 20°C.
Reloaded filament, started printing and while printing the brim the clicking began. What I noticed is that the shaft of the extruder stepper motor clearly skips back as well with every click. I thought it was only the idler gear somehow (due to gear teeth not touching).
If I'm not able to fix this issue in the next couple of days I will do one of two things:
Buy this bondtech extruder: https://www.bondtech.se/en/product/prusa-i3-mk2-5-mk3-extruder-upgrade/
Or for a 150€ more buy an Anycubic I3 Mega .
Simply fed up with this.
RE: PRUSA edition heat break easily jam/clog with PLA
Jan - it just occurred to me you might have a motor or wire failure. If the extruder gear is jumping, but not really turning, a bad wire will cause this. Sometimes it connects, sometimes it doesn't, so you'll get a good print one time, bad prints the next: intermittent.
Try this - it's important to not move anything - so follow the instructions carefully.
Start a new print, and when it starts clicking: press the X button to reset the printer. Hopefully nothing moves as the printer resets..
Then use Settings:Temperature:Nozzle heat the nozzle to 210c. Once the nozzle is at temp, use Settings:Move Axis:E-Axis to extrude a few millimeters of filament. Does the extruder click? I am hoping it does.
Now, wiggle the extruder cable harness while extruding and see if the clicking changes or stops... I am hoping it does.
A bad cable - and they do break with lots of use - is an easy fix.
RE: PRUSA edition heat break easily jam/clog with PLA
What I see in all yours comments is exactly the issue I described in my first post of the topic (see the attached PDF in the post.)
The only fix is to replace the PRUSA heat break (with bottleneck) with an ORIGINAL E3D heat break (flat diameter) and keep the same measure of the internal diameters.
I received mine on Friday. I will install in the coming days.
RE: PRUSA edition heat break easily jam/clog with PLA
Jan - it just occurred to me you might have a motor or wire failure. If the extruder gear is jumping, but not really turning, a bad wire will cause this. Sometimes it connects, sometimes it doesn't, so you'll get a good print one time, bad prints the next: intermittent.
Try this - it's important to not move anything - so follow the instructions carefully.
Start a new print, and when it starts clicking: press the X button to reset the printer. Hopefully nothing moves as the printer resets..
Then use Settings:Temperature:Nozzle heat the nozzle to 210c. Once the nozzle is at temp, use Settings:Move Axis:E-Axis to extrude a few millimeters of filament. Does the extruder click? I am hoping it does.
Now, wiggle the extruder cable harness while extruding and see if the clicking changes or stops... I am hoping it does.
A bad cable - and they do break with lots of use - is an easy fix.
Another day, a new round of clicking... 🙁
I tried your suggestion: I stopped the print (using x button) while clicking, heated the nozzle and through settings I let the extruder extrude a bit: the clicking continued. Also when i was wiggling the cables. You can clearly see the stepper motor shaft skipping back. (I put a mark on the shaft using a pen).
I would have been very surprised if this would have been the cause of my problems: since I got the printer I have had problems printing PLA with the extruder clicking. I then switched to NGEN and never had any issues. Now that I want to use PLA again the same clicking occurs.
RE: PRUSA edition heat break easily jam/clog with PLA
Jan - it just occurred to me you might have a motor or wire failure. If the extruder gear is jumping, but not really turning, a bad wire will cause this. Sometimes it connects, sometimes it doesn't, so you'll get a good print one time, bad prints the next: intermittent.
Try this - it's important to not move anything - so follow the instructions carefully.
Start a new print, and when it starts clicking: press the X button to reset the printer. Hopefully nothing moves as the printer resets..
Then use Settings:Temperature:Nozzle heat the nozzle to 210c. Once the nozzle is at temp, use Settings:Move Axis:E-Axis to extrude a few millimeters of filament. Does the extruder click? I am hoping it does.
Now, wiggle the extruder cable harness while extruding and see if the clicking changes or stops... I am hoping it does.
A bad cable - and they do break with lots of use - is an easy fix.
Another day, a new round of clicking... 🙁
I tried your suggestion: I stopped the print (using x button) while clicking, heated the nozzle and through settings I let the extruder extrude a bit: the clicking continued. Also when i was wiggling the cables. You can clearly see the stepper motor shaft skipping back. (I put a mark on the shaft using a pen).
I would have been very surprised if this would have been the cause of my problems: since I got the printer I have had problems printing PLA with the extruder clicking. I then switched to NGEN and never had any issues. Now that I want to use PLA again the same clicking occurs.
RE: PRUSA edition heat break easily jam/clog with PLA
Jan - normally, when the extruder is clicking, it is because the motor is turning and grinding the filament down: each click due to the small teeth breaking loose another piece of filament. The important part here is that the motor is usually turning while this is happening, not stalling.
Try this one other test ... wait until it starts clicking again, then back the two tension screws out until they are loose. Then trying extruding manually. If the click stops when they are loose, then turn the screw in until you feel they just barely compress their springs. One turn past contact should be enough.
RE: PRUSA edition heat break easily jam/clog with PLA
Jan - normally, when the extruder is clicking, it is because the motor is turning and grinding the filament down: each click due to the small teeth breaking loose another piece of filament. The important part here is that the motor is usually turning while this is happening, not stalling.
Try this one other test ... wait until it starts clicking again, then back the two tension screws out until they are loose. Then trying extruding manually. If the click stops when they are loose, then turn the screw in until you feel they just barely compress their springs. One turn past contact should be enough.
I tried this without success. What I also tried is this:
I backed the two screws out until they were loose and tensioned them again while trying to reload the filament. At a certain point the filament loaded and flowed from the nozzle. I then started a print: the skirt was barely being extruded so I tensioned the two screws one turn. The skirt was now printed ok, and the print went on to the brim. Then the clicking began as you can see in the video below (sorry for the lousy focus at the end, my old Amiga 500 is more in focus than anything else :-)). This time it was the filament that was skipping I think. I tensioned the screws a bit further, the clicking stopped and extrusion resumed. Then the filament clicking began again, I tensioned the screws some more but then I noticed the shaft of the stepper motor skipping back again. I don't have this on camera as it was impossible to film and tension the screws at the same time.
So no matter what I try: PLA does not print.
RE: PRUSA edition heat break easily jam/clog with PLA
I know this is PLA, but have you tried drying your filament? The problems you are having sound exactly like the issues I was having printing nylon, until I dried the filament. Nylon is way more hygroscopic than PLA, but maybe its worth a shot, especially since none of the other adjustments/changes seem to be impacting the behavior of your printer.
RE: PRUSA edition heat break easily jam/clog with PLA
have u tried taking your extruder apart ... then push the ptfe tube in while pulling the collet that secures it out ???? i heard some people badley assembled this particular thing and if the ptfe tube as slight verticle movement clicking and blocking is for a matter of when, when finished the collet should be pulled away from top of the heatsink buy about 3-4 mm and the ptfe tube will not move
RE: PRUSA edition heat break easily jam/clog with PLA
At least that initial clicking sounded like a normal filament skip and the motor was turning. Tension is a happy medium between just enough but not too much. When the screws are buried as yours were, the two drive gears can actually jam, causing motor stalls.
The tips of the two screws - on my printer - are about level with the door plastic. Some PLA needs a bit more, some PLA gets by a turn less.
The last place to examine is the actual nozzle temperature accuracy. It is possible your hot end is just not hot enough due to a failing thermistor; though more likely if you've been printing ABS or Nylon, but not unheard of printing PLA. .
First, make sure the thermistor set screw is snug (not tight or you can break the glass envelop inside). You'll need an ohm meter or DMM to test the part. Let things cool down to room temp, and have a accurate room thermometer nearby, disconnect the thermistor from the EINSY, and measure the resistance. At 25c the thermistor should read 100k +/-3% (97k-103k). If the room temp is a bit higher (30c), the resistance will be a bit lower (~85k). If the room temp is a bit lower (20c), the resistance will be a bit higher (~110k). note: it is best to use a 25c room temp: the 20c and 30c resistances I wrote down are educated guesses and may be wrong.
-42G is closest to MK3 thermistors.
ps: this is a silly question, but your two door tension screws do have the springs on them, right?
RE: PRUSA edition heat break easily jam/clog with PLA
At least that initial clicking sounded like a normal filament skip and the motor was turning. Tension is a happy medium between just enough but not too much. When the screws are buried as yours were, the two drive gears can actually jam, causing motor stalls.
The tips of the two screws - on my printer - are about level with the door plastic. Some PLA needs a bit more, some PLA gets by a turn less.
The last place to examine is the actual nozzle temperature accuracy. It is possible your hot end is just not hot enough due to a failing thermistor; though more likely if you've been printing ABS or Nylon, but not unheard of printing PLA. .
First, make sure the thermistor set screw is snug (not tight or you can break the glass envelop inside). You'll need an ohm meter or DMM to test the part. Let things cool down to room temp, and have a accurate room thermometer nearby, disconnect the thermistor from the EINSY, and measure the resistance. At 25c the thermistor should read 100k +/-3% (97k-103k). If the room temp is a bit higher (30c), the resistance will be a bit lower (~85k). If the room temp is a bit lower (20c), the resistance will be a bit higher (~110k). note: it is best to use a 25c room temp: the 20c and 30c resistances I wrote down are educated guesses and may be wrong.
-42G is closest to MK3 thermistors.
ps: this is a silly question, but your two door tension screws do have the springs on them, right?
@Willieam I tried a fresh PLA spool right out of the airtight packaging after the first problems arose.
@KarlDavis Yes, I took it apart again (several times actually). As stated before I replaced the heatbreak, pfte tube and nozzle in one go in an attempt to solve the clicking problem and clogs.
@Tim Tried three differents prints which all failed with different tension levels on the screws. No difference. Or the extruder clicks because of the filament, or because of the motor skipping back.
I tested the thermistor and that seems ok:
RE: PRUSA edition heat break easily jam/clog with PLA
the rod the the idler sits on is free moving but doesnt wobble ?
RE: PRUSA edition heat break easily jam/clog with PLA
the rod the the idler sits on is free moving but doesnt wobble ?
Yes, the idler shaft is in the middle, no wobble.