Newbie - How to remove extruder?
hi
My 1 year old prusa MK3 has been giving problems for longer prints (above 5 hours at higher resolution 0.1 and above).
I've had this latest clog in my extruder. i've heated the extruder to 270 degrees, and tried to push the hardened filament bits downwards using the allen key type tool, but to no avail. can someone advise how i can remove the extruder unit? the pics show how far i've come and i couldnt find anything useful on youtube.
seperately, my z axis is unable to move downwards using the settings mode. is there anyway i can solve this?
thanks. this is frustrating and i hope to learn from the wiser, well traveled tinkerers out there.
RE: Newbie - How to remove extruder?
attaching more pics as i cant do multiple pics on 1 post
RE: Newbie - How to remove extruder?
last pic. sorry as lighting wasnt great
RE: Newbie - How to remove extruder?
By taking the stepper motor apart you have now pretty much ruined it. You should never need to take apart a stepper. I suspect it wont work properly ever again.
First would be to read this https://help.prusa3d.com/en/article/clogged-nozzle-hotend-mk3s-mk2-5s_2008/
For disassembly instructions you should have gone through the assembly manual and reversed the steps on extruder assembly. https://help.prusa3d.com/en/guide/5-e-axis-assembly-textile-sleeve_71288
For removing clogged bit like that you could have first tried a cold pull (research how to do those, theres lots of guides around). That would remove anything stuck down there upwards with the removed filament. Next step if that didn't work would be to heat it up and remove just the nozzle. That should then allow you to force filament downwards without it having the pass through the small diameter of the nozzle.
If the filament is stuck in the ptfe tube then at that point is the time to partially disassemble the extruder. At none of those points does the stepper motor come apart. The screws holding the stepper to the extruder go from the back into the front plate.
On the Z axis movement, the printer firmware wont move the z axis below where it thinks zero is. If you stepper is say 50mm up and you power cycle the printer the firmware will think that is zero (actually it will assume its unknown but wont allow you to go down). You would need to perform a homing sequence first so that the printer can establish xyz zero positions before it will then allow you to move it up. As that requires the pinda probe to be working to home z you need that wiring to be in place.
RE: Newbie - How to remove extruder?
Hi neophyl, thank you so much for your guidance.
When i read your about the stepper my knees turned wobbly and my blood pressure must jave dropped. Thankfully i put back everything and followed your pointers to remove the hotend.
Attached are pics of the clog, now removed. This always happens during longer prints above 5 hours or so. Do u know how i can get more consistent prints without clogging? Thanks again
RE: Newbie - How to remove extruder?
One more of the clog within the extruder
RE: Newbie - How to remove extruder?
Looks like you finally are getting to the original issue. I'd recommend checking how to set the heat break in properly. It's also in the manual.
RE: Newbie - How to remove extruder?
Yeah from the amount of plastic on top of your heatbreak you have been running with an incorrectly assembled nozzle. That leads to plastic working its way both up and down the threads, and eventually dripping down onto your prints both from the top and bottom of the heatblock. Things must be assembled properly.
As well as leaking the gap causes a small 'reservoir' of plastic to form which messes up printing in other ways too. When the extruder pushes plastic out there can be a delay, when it stops pushing filament out theres another delay as the gap changes the pressure flow slightly. It can also lead to problems removing filament after prints etc.
You can clean all that up and re-assemble for the rest of the hot end but I would certainly be looking at getting a new extruder stepper motor. They are magnetised at the factory after being assembled. Even if it works after re-assembly its usual to lose a third or more of the motor torque. As the extruder stepper has the most difficult job out of all of them requiring the most torque its highly likely to be insufficient for the job now.
RE: Newbie - How to remove extruder?
There is a specific instruction sheet to remove the extruder after a complete build. Search around for it. I have done it more than once when I was trying to solve my mk3s filament detector problems.
The instructions are more than just reversing the build.
RE: Newbie - How to remove extruder?
Also - post up an image of the nozzle in the heater block; changing or replacing the nozzle without closely following the E3D-V6 procedure can lead to this exact problem (leaking extruder). If the nozzle is bottomed out on the block, the HEX part in contact with the block and not standing off a turn or two, it was assembled wrong, and putting things back together that way will - well - put you right back here in a few days.
RE: Newbie - How to remove extruder?
Thanks so much guys. I really appreciate the guidance. Sorry for delays as i have so little time to tinker.
I now have new issues with the filament sensor, will start a seperate SOS thread.