Extruder motor clicking, underextrusion
Hey everyone!
I seem to have some sort of feeding problem with my MK3S.
The extruder motor is having a hard time pushing filament through. Usually, first layer is OK. It also works better if I print on a bit higher temperature than the default mode (both for PLA and PETG).
However, when the fan comes on and temperature temporarily decreases, underextrusion really messes up my print. Sometimes the nozzle completely clogs, with no material coming out, and I have to heat the hotend even more and bring out the good old needle. If things are good, I can force some filament through by pushing it down manually.
I've changed the PTFE tube twice, taken the hotend apart and cleaned the parts with a needle, heat gun and a brass brush. I then re-applied some cooling paste to the heatbreak and put it all back together. I finally reeeeeally tried to make sure the PTFE tube was pushed all the way down in the heatsink before lifting the little ring to lock the tube in place.
But now, it happened again. This is driving me insane, since it renders my otherwise awesome printer basically useless.
What should I do?
I'm super grateful for any advice!
RE: Extruder motor clicking, underextrusion
Did you always use the same nozzle, perhaps with different materials?
When you remove the nozzle can you push/extrude the filament through easily?
If you have an unused nozzle try using it instead of the old nozzle which could be at least partly clogged.
A cold pull could also help to get a (inside) clean nozzle.
RE: Extruder motor clicking, underextrusion
@frans-h
Yeah, I've used the same nozzle for different kinds of PLA and also PETG. Could that be a problem?
And can I perform a cold pull with PLA or PETG?
RE: Extruder motor clicking, underextrusion
Well, I only had a clogged nozzle once and I'm using different materials too (like most people). The best action is dependant on what is the cause of the clogging. The use of different materials can't be the single cause but could help. When the nozzle temperature in the past heated up way too high even for a shorter time, you could have a burned layer of PLA inside the nozzle. That would be the worst situation where even a cold pull might not help. If that's not the case you could try to print a part with PETG (or any abrasive filament material) with a fast setting and a bit higher temperature (~5° above the upper temperature recommendation for that material). Personally I would change the nozzle first a see if that solves the problem. If yes, the old nozzle was definitely clogged. I leave my old nozzles for a week in 32% hydrochloric acid to get them clean 🙂 If you want to try a cold pull I would use the material with the higher temperature (PET) to make sure the filament is well bonded to the material remaining in the nozzle. Make sure that the bondtech gears don't interfere with the filament. You might have to pull quite hard. Make sure that you don't damage any x-axis parts.
RE: Extruder motor clicking, underextrusion
@frans-h
Yeah, I've used the same nozzle for different kinds of PLA and also PETG. Could that be a problem?
And can I perform a cold pull with PLA or PETG?
No, printing with different materials on the same nozzle shouldn't be a problem as long the nozzle type suits the requirements for the material type you want to print (abrasive = hardened nozzle etc.). PLA and PETG should work with every nozzle type.
You can use PLA for cold pulls without problem. As far as I know nylon is the best material type for it but it will also work with PLA etc. But be careful and make sure you follow the instructions in this guide: Prusa knowledge base - Cold Pull
What filament brand do you use?
How is the environment temperature?
Good Luck.