Material Feed Failure, but Printer Keeps "Printing"
Sadly, I've not been able to use my Core one since October. Between delays in response from support and delays getting parts to me, this is my reality right now. I figured I would post here while waiting on support to see if there are any ideas.
I experienced a "hot end fan not running" error sometime back in late October and worked with chat/email to get me squared away on that. Replaced the hot end fan, to no avail, and eventually Prusa sent me a new loveboard. This did fix my error and the printer seemed back to normal, or so I thought. Since that time, I've had no successful prints on my machine.
Now, I am experiencing an issue with filament feeding that I cannot understand. I can load/unload filament like normal. I've even used the "purge more" function several times and filament continues to feed just fine. However, when I start a print job I get a few minutes into the print and all of a sudden material will stop feeding, but the printer will continue on it's path while putting down no filament. I can hear the stepper motor used for feeding the filament making what sounds like a "grinding" noise but I believe this is just what a stepper motor sounds like when too much force is required and it can't actually move. I will abandon the print, and can choose the "unload filament" and the stepper will make a momentary "grind" noise again, and then catch and eject the filament normally. I can then reload and do the entire process over again, but the print will always fail. I am using PLA, and have tried several different MFG's/colors now but all produce the same results. Temps are based on the pre-loaded settings in the prusa connect app for this filament. The file I am printing is the same file I was using when the hot end fan error cam up originally (made it about 75% of the way through that print before getting the "hot end fan not running" error).I have opened the idler swivel and cleaned the drive gear out with a toothpick. It did have a little build up in the gear, but it all came out easy. It was NOT the color of the current print which tells me it wasn't slipping on the material I had loaded in. I have tried slightly tightening the adjustment screws for the idler swivel as well with no change, but the material consistently has noticeable tooth marks in it suggesting it is grabbing just fine. I have done a cold pull process following the prusa guideline found here: https://help.prusa3d.com/article/cold-pull-26702-mk4s-13702-mk4-28702-mk3-9s-21702-mk3-9-23702-mk3-5-28702-mk3-5s-17702-xl_445071
The printer has roughly ~500 hours on it, and again, has not made one successful print since the loveboard was replaced. I have removed/reseated the nozzle to ensure it's all the way in. I have removed/reseated the teflon feed tube into the extruder as well and it feels firmly seated in there. I am unsure what else to test at this point. I have uploaded two videos to youtube that I will share here.
First video showing loading of filament, and extended purges working just fine:
http://youtube.com/watch?si%3D8jtLHPTNGmW1dbBu%26v%3DrZsrGJWWul0%26feature%3Dyoutu.be&source=gmail&ust=1765642406764000&usg=AOvVaw28RFkIq4QFtNWNmaQUSM2 G">youtube.com/watch?si=8jtLHPTNGmW1dbBu&v=rZsrGJWWul0&feature=youtu.be
Second video showing a print job from start until failure. (You can hear the extruder motor start making it's "grinding" noise around 12:50):
Appreciate any insight!
Thanks,
Mike
RE: Material Feed Failure, but Printer Keeps "Printing"
Spoke with chat yesterday and they suggested that I have the print fan and hot end fan connections swapped most likely. Verified today that is not the case. They believe I am experiencing heat creep and it's causing the filament to swell in the "cold zone" and causing a jam. That theory makes sense since it seems to happen nearly in the same spot of the print each time which suggests the heat soak is taking X amount of time, each time and causing the error. Chat also suggested running all calibration tests since I did a new love board. Machine ran through all calibration tests without issue, including fan tests. When I manually turn up the nozzle temp, the hotend fan kicks on right around 50*C like it should and the print fan does not run. This tells me the fans are hooked up correctly.
Not sure where else to look at this point, but currently have a boat anchor for a printer. I'm missing out on printing x-mas decorations with my 3 year old 🙁
RE: Material Feed Failure, but Printer Keeps "Printing"
Have you tried just printing the PLA with the door open? I rarely print PLA but when I do, I don't use a HF nozzle and I leave the door open. PLA has a tendency to jam in a Core One.
Also, was your printer factory assembled or a kit?
RE:
If you (or Prusa support) suspect heat creep, have you enabled the display of the heatbreak temperature in the footer line of the display? Unless this has changed in the more recent firmware, the printer comes with one unused slot in the footer, and you can add the heatbreak temperature display there: Settings > User Interface > Footer
RE: Material Feed Failure, but Printer Keeps "Printing"
IMO, something doesn't look right about the material coming out of the hot end, especially later. Is there any chance there's something clogging the nozzle, something that moves around and eventually plugs it completely, then moves back again? Do you have a spare nozzle to try?
RE:
Have you tried just printing the PLA with the door open? I rarely print PLA but when I do, I don't use a HF nozzle and I leave the door open. PLA has a tendency to jam in a Core One.
Also, was your printer factory assembled or a kit?
Factory assembled unit. I have considered trying with the lid off and/or door open. But the room it's in isn't any hotter than normal, and I would guess 475 of my 500 hours on my printer have been printing PLA with zero issues until this loveboard swap.
If you (or Prusa support) suspect heat creep, have you enabled the display of the heatbreak temperature in the footer line of the display? Unless this has changed in the more recent firmware, the printer comes with one unused slot in the footer, and you can add the heatbreak temperature display there: Settings > User Interface > Footer
I have not tried that, but the last print I did I monitored nozzle temps and heatbreak temps and didn't see anything crazy? Unsure of what is normal there. Nozzle stayed right around 220*C like suspected and heatbreak was under 40*C the entire time, usually 36*-38*.
RE: Material Feed Failure, but Printer Keeps "Printing"
IMO, something doesn't look right about the material coming out of the hot end, especially later. Is there any chance there's something clogging the nozzle, something that moves around and eventually plugs it completely, then moves back again? Do you have a spare nozzle to try?
I guess it's possible? Seems strange it would clog in nearly the same spot of the print each time. I can also immediately clear the material (unload) without issue and then re-load and purge multiple times without issue. Only a problem once I am mid-print. I do not currently have a spare nozzle. I have done a cold pull too without seeing anything out of the oridnary.
RE: Material Feed Failure, but Printer Keeps "Printing"
This is so strange. Just like a car that, with fuel flow, air and spark, almost has to run, if the hotend is at the temperature you think it is, isn't plugged, and has filament forced into it, it should print. Think Occam's razor here. PLA at 230 C is quite liquid. Mine purges as a narrow shiny string. I get a well-defined fairly narrow band when it lays down at the front right corner of the build plate. What I see in the video is a heavier string and a sloppier right corner. Later, after the problem, the purge seems thick and doesn't drop straight down. I wonder if the hotend temperature is really at the reported temperature. Thermistor issue? Does anybody know how to check the actual nozzle temperature, independent of the reported temperature? I'm grasping but figure you can use any and every idea.