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Poor extrusion (Prusa i3 Plus 1.75 mm)  

Marco Alici
New Member
Poor extrusion (Prusa i3 Plus 1.75 mm)


I'm using my Prusa i3 Plus 1.75 mm since April 2016.

In the last prints I have the (bad) results as in the image below. Even using good old successful .gcode files I observe what I suppose to be underextrusion. This is what I have already done:

  • The problem also occurrs with a brand new nozzle;
  • The problem also occurrs with a brand new vacuum sealed PLA filament;
  • If I loosen the extruder idle screws, the filament slips over the hobbed pulley;
  • If I tighten the extruder idle screws, the motor looses steps;
  • The problem occurs printing PLA up to 245°C (I usually print at 215-220°C, heated bed at 60°C)
  • I suspected a relation with the ambient low temperature, but the problem also occurs when printing at 20°C;

What I haven't done yet:

  • to check whether the nozzle temperature is real. Unfortunately I have no tools to perform a local precise temperature measurement, I suppose that the only way is just to buy a heater cartridge and/or thermistor replacement.
  • to check for wear of the hobbed pulley. Same as before, I should buy a new pulley to check.


Any ideas to solve such a frustrating issue?

Thank you in advance!




Posted : 24/01/2020 8:48 am
Marco Alici
New Member
Topic starter answered:
RE: Poor extrusion (Prusa i3 Plus 1.75 mm)


Thanks to Michael Kuznetsov (Prusa Technical Support) who suggested me to check the hotend PTFE tube!

It was almost completely occluded. I changed it as explained here.

I also took the opportunity to change/upgrade some other hot-end parts (heater block, heater cartridge and thermistor). Even if I found that there is some PIDs tuning to do, I tried to print the same file and now it works perfectly!

Posted : 14/02/2020 11:46 am