Poor extrusion (Prusa i3 Plus 1.75 mm)  

Poor extrusion (Prusa i3 Plus 1.75 mm)

Hi,

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!

Cheers,

Marco