prusa mini underextrusion issue  

RE: prusa mini underextrusion issue

Probably best to run an extruder calibration by marking a fixed amount of filament above where it enters the IR sensor cover (the top of the extruder assembly). A usual amount to mark is 120mm, but the amount isn't that important as long as you know exactly how much it is. Then advance the extruder manually or by gcode to 100mm if you marked at 120mm. The mark you made should be exactly 20mm above the IR cover. If is under or over you can measure the difference and can calculate the amount of over or under extrusion and adjust the printer. 

There lots of articles and videos to show you how with the equation to find the correct compensation modifier if you find it is off. At the very least you will quickly find out if you are really extruding the same amount the printer thinks it is. Here is a simple how to video for an Ender, but the same applies to Prusa printers except you change the e steps a bit different. 3D Printer Extruder Calibration

And here is a blow by blow text of how to do this on a Prusa. Prusa-i3-MK3-Tips-Tricks and go to the calibrating extruder e steps.

If it under extrudes remember to check the extruder idler spring tension before adjusting the e steps to make sure the tension is enough to not skip on the filament.

RE:

Are you on the stock extruder? Did you have from the beginning all this problems?

" Any suggestions?"

For <15 USD you can do your own upgrade to a dual-geared extruder. This solved all my extruder issues. I know it is not what you directly asked fore but it may help you on the long run 🙂

https://www.printables.com/model/118593-cm3d-extrusor-mini-fs

Posted by: @makeitdude

I have been printing with my prusa mini for about 14 months and I am having some trouble with the extrusion. All prints off the machine are brittle and underextruded no matter the temperature. I have cleaned out the extruder, adjusted the idler spring, replaced the ptfe lining the hotend with some capricorn tubing, and cleaned out the nozzle. Any suggestions?

RE: prusa mini underextrusion issue

Is this on all filaments, or just one?

RE: prusa mini underextrusion issue

this has happened with all filaments that I have tried including pla pvb and petg

RE: prusa mini underextrusion issue

I have tried running similar tests and adjusted the extrusion multiplier to match and have even tried surpassing that so it should have over extruded, however the under extruding persists.

RE: prusa mini underextrusion issue

Can you post an image of your hotend from the side with the grub screws.  

RE: prusa mini underextrusion issue

RE: prusa mini underextrusion issue

Does the filament pop while printing?

RE: prusa mini underextrusion issue

no it does not I have been able to print the material on a modified ender 3 with no problems. I have also tried replacing the nozzle from hardened steel to brass and it doesn't help anything. I am using Prusa's own profiles as I am using prusament.

RE: prusa mini underextrusion issue

I am facing similar issue. Did any of the advice that was given here work for you?

RE: prusa mini underextrusion issue

I went with new thermistor + heatin element + 0.6 nozzle now its good. Also temps around 205 works best