PETG underextrusion problem with Mini  

PETG underextrusion problem with Mini

Hello,

My mini printer had an incident during my last print. Few hours in the print filament thread got bent badly and once the bent part was pulled into filament sensor and PTFE tube the resistance force was so big that it was barely moving and for few more hours my printer was pretty much running dry spewing only droplets of filament.

After clearing the issue now I'm experiencing persistent underextrusion problem. First layer of print looks ok, it's continuos without gaps but every next layer is completely messed up. I'm attaching some photos of a test print - a 10x10 cube printed with all stock settings in PrusaSlicer for printer, filament and print settings (PETG material).

Following this guide https://help.prusa3d.com/article/clogged-nozzle-hotend-mini-mini_112011?product=mini-2 I already attempted several troubleshooting steps. After each one problem still persisted.

1. Adjusted extruder idler screw. There is no clicking. I can see filament being pulled in by extruder. I also cleaned gear that pulls filament.

2. Unloaded/Loaded filament with extra filament purge. Filament coming out of nozzle looked fine by me.

3. I attempted to preform cold pull but it was unsuccessful. Every time I tried it filament would simply break at marked point and I was not pulling anything out of hotend at all.

3. I followed the "Forcing the clog out (load impossible)" without the step where it says to use 1.5mm straight wire. I let it heat up to 280 degree, waited few minutes for filament to spill out and then used included acupuncture needle to clear nozzle.

Then I went through all self tests including Z axis calibration. They all completed successfully and Z axis calibration results turned out fine by me (zig-zag pattern and manual adjustment). Yet again attempting to print my test cube ends up with failure.

This is how filament flow looks like during filament purge

Looking for assitance