Another heat creep jam problem  

Re: Another heat creep jam problem

I figured out what was wrong.

The pin for the idler wheel had been slightly of to one side and caused the idler to be pushed since it did not have good hold on both sides. This made the printing fail after some time due to slight grinding on the filament that made filament packing around the bondtech gear and less grip. This turned to clog after some time.

After I reseated the pin and put some small amount of epoxy on each end this never happened again. Not done any other changes to my printer and it still print without clog.

RE: Another heat creep jam problem

I'm sorry I felt the same way. The first weeks were perfect and great fun. Then suddenly problems started. At first I thought the nozzle was blocked, but the problem remained. I checked the idler, changed the PFTE tube, cleaned the hotend etc. So far nothing has worked continuously. Prints break off or are run without filament feeding. The print no longer sticks to the plate, causing massive clumping. I have read and tried the entries here in the forum. Unfortunately nothing worked. I am really sad and disappointed.

RE: Another heat creep jam problem

clean the build plate with soap and water using only clean paper towels and only handle the plate by the edges. then check your live Z. dirty build plate and too high a live Z are about the only causes of prints not staying on the plate

RE: Another heat creep jam problem

This may seem silly and irrelevant, but I was so intent on the hot end, settings, and everything associated with that part of things that I didn't notice that a couple layers of filament on the spool had moved on top of the top layer, causing it to stop printing, or slow it down enough to become super stringy, looking like a clog.  I sorted out the spool and keep an eye on it now, and have caught it becoming taught a few times.  BUT have had no jams since discovering this.

We're so intent on the pushing of the filament that we sometimes forget that pulling is just as important and causes many of the same symptoms.

RE: Another heat creep jam problem

Thank you, all,  for the good posts and for your hard work trouble-shooting this.  I've been burning through PTFE tubes like crazy due to frequent jams in the extruder.  Much of the same looking filament pulls, here, too.  Last thing I can try is to increase the nozzle temp as suggested previously.  Some of the filaments I've used work perfectly.  Some (like Prusament) don't work at all...jams at layer 2 or 3.  Found that the cheapest PLA available, which I had given up on, works wonderfully.  This topic has been quiet for a while, but please let me know if you found anything new.   

RE: Another heat creep jam problem

If an unload after a jam has a mushroom stub, and that stub measures 2.2 mm, it is concrete evidence you are suffering from a jam caused directly by the Prusa modification to the heat break.   

Lower melt point PLA may work more reliably, or printing with higher nozzle temperatures, but your prints are still suffering quality issues due to this problem.  

RE: Another heat creep jam problem

I have a reoccuring problem on my MK3S, like the one pictured a few posts later. When printing, I can come back to the printer and its clicking at the extruder and the feed has stopped and is printing in mid-air. This has happened about every two weeks. This lastly happened using Prusa filament and I have dthe brass nozzle with a e6d steel nozzle (made no difference). I have to take the extruder apart and remove the ptfe tube to fix this jam. Its very frustrating trying to figure out the cause. The filament will have a bulb at the lower end that won't retract and eject when the extruder is reheated even. Also at the top, if I try to remove the filament it will snap off just above the top of the ptfe tube as it appears slightly smushed and will break at that time. The only repair is to go thru the procedure to loosen and tilt the heat sink to pull it out, remove and replace the tube. I've tried adjusting the tension on the bondtec gears. I seem to think this occurs on areas of fine detail and maybe the filament is retracting a lot. I've only had this printer a few month and this is the major failure that I run into from failed prints.

What do you recommend or is there a setting that needs to be changed. I run the default settings in the prusa slicer.

RE: Another heat creep jam problem

I have a reoccuring problem on my MK3S, like the one pictured a few posts later. When printing, I can come back to the printer and its clicking at the extruder and the feed has stopped and is printing in mid-air. This has happened about every two weeks. This lastly happened using Prusa filament and I have dthe brass nozzle with a e6d steel nozzle (made no difference). I have to take the extruder apart and remove the ptfe tube to fix this jam. Its very frustrating trying to figure out the cause. The filament will have a bulb at the lower end that won't retract and eject when the extruder is reheated even. Also at the top, if I try to remove the filament it will snap off just above the top of the ptfe tube as it appears slightly smushed and will break at that time. The only repair is to go thru the procedure to loosen and tilt the heat sink to pull it out, remove and replace the tube. I've tried adjusting the tension on the bondtec gears. I seem to think this occurs on areas of fine detail and maybe the filament is retracting a lot. I've only had this printer a few month and this is the major failure that I run into from failed prints.

What do you recommend or is there a setting that needs to be changed. I run the default settings in the prusa slicer.

RE: Another heat creep jam problem

Posted by: michael.j51

I have a reoccuring problem on my MK3S, like the one pictured a few posts later. When printing, I can come back to the printer and its clicking at the extruder and the feed has stopped and is printing in mid-air. This has happened about every two weeks. This lastly happened using Prusa filament and I have dthe brass nozzle with a e6d steel nozzle (made no difference). I have to take the extruder apart and remove the ptfe tube to fix this jam. Its very frustrating trying to figure out the cause. The filament will have a bulb at the lower end that won't retract and eject when the extruder is reheated even. Also at the top, if I try to remove the filament it will snap off just above the top of the ptfe tube as it appears slightly smushed and will break at that time. The only repair is to go thru the procedure to loosen and tilt the heat sink to pull it out, remove and replace the tube. I've tried adjusting the tension on the bondtec gears. I seem to think this occurs on areas of fine detail and maybe the filament is retracting a lot. I've only had this printer a few month and this is the major failure that I run into from failed prints.

What do you recommend or is there a setting that needs to be changed. I run the default settings in the prusa slicer.

 

Same here. I've only had my MK3S for around a week and after printing perfect for a while, all out of a sudden it got totally jammed during a long print using standard PLA and a standard prusaslicer profile with variable layer height (Which may or may not confirm your theory of it happening with very fine detail?). Heating up the extruder to 250 i wasn't able to push the filament through the tube with an allen key. I still have the printer sitting at home like this because i got too frustrated after seeing all the filament stuck so hard all the way up to the gears. So the only known permanent solution to this is to buy a new heatbreak by a third party supplier, is that right? With the amount of reports on this, i don't understand why Prusa hasn't addressed this yet. Has anyone contacted support and seen what their suggestion is?

RE: Another heat creep jam problem

Posted by: jason.s6

Were there any updates for this? I just started having the same issues with Clear PLA from Fillamentum.

I've replaced the PTFE tube, checked the gears, tried slower, faster, hotter, cooler and the jam only happens after a lot of retractions then I have to unload, snip and reload and it prints fine for a bit.

It's all about heat. What are your ambient printing temps? Are you printing in an enclosure?

It may be that replacing the heatbreak or applying thermal paste is all that's needed. You could have a filament feed path issue and only need to remove the obstruction or check your extruder idler.

Any of of these or many other factors can both cause the extruder to work hard and contribute to heat. Reducing one or any of these can help. The most common issue and easiest to fix is increasing airflow, either opening an enclosure or moving more air around the hotend exhaust.

RE: Another heat creep jam problem

Please learn me something, here.  What is this "heat break" that has been brought up a couple of times.  And, where/how would one apply a thermal paste?  What is thermal paste and how do you get it?  I'm willing to try anything at this point.  i3 MK3S printer.  Does that change any answers or advice?  

RE: Another heat creep jam problem

RE: Another heat creep jam problem

an E3d V6 extruder, looks like this, in cross section

here are the parts of the extruder
lines point to the heatbreaks, one is shown inserted in the heater block, along with a nozzle, heater cartridge and thermistor cartridge.
spare heater and thermistor are shown as well.

heat paste comes in tubes like this  and costs about £2.00

Boron Nitride heat paste is the Bees knees... and costs £12.00

Chris Warcocki has a video on assembly here>

hope this helps

regards Joan

RE: Another heat creep jam problem

That's exactly where the freeze up happens.  Today it's so bad I can't get a new PTFE tube inserted. 

Also, where does this paste get applied, and what is its function?  

RE: Another heat creep jam problem

I had the same symptoms as everybody this far. I was able to fix it using the above ibico74 post. My unit is a MK3 upgraded to MK3s. There is space inside the body for the idler wheel pin to move out of position. Since I've had multiple 6h runs fail like this at maybe 4h with me being out of reach, my wheel cover already shows a spot where the idler wheel has been grinding away.

The additional symptom I had was that the idler wheel cover did not open easily, because the pin was blocking it. I had to unscrew the lid hinge to open the cover.