Reinstalled extruder, but now getting under-extrusion: causes?
 
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Reinstalled extruder, but now getting under-extrusion: causes?  

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Mat
 Mat
(@mat-3)
Active Member
Reinstalled extruder, but now getting under-extrusion: causes?

Hello!

About 2 hours into a print, filament stopped coming out. Sounds like a block, right?

After cancelling the print, I heated up the extruder to PLA temp, and went into settings > move axis > extruder. The filament reversed back out okay, but when I increased the value it seemed to stop up against something.

Clogged hotend?

I gently pushed the filament whilst increasing the value, and then filament started to extrude again.

Does that mean it's unclogged now, and I can carry on? Or should I address the initial cause?

Also I noticed that the layers were not very well stuck together. I was printing a project box, and the sides had started printing but they just lifted off the base.

Sounds like classic under-extrusion right?

What is the cause of these two things?

Here's the background:

This was my first print after reinstalling my hotend to the extruder, after replacing the heater and thermistor blocks.

I also took the opportunity to replace the PTFE tube with a new one (sourced from Prusa shop so it should have the correct angles and cuts etc)

Calibrated ok and things seemed fine. I ran a long print and set up an electric heater nearby my enclosure as the enclosure is near a window and it can get drafty (temps of around 2 degrees in the nighttime here).

There seem to be quite a few variables so I'm not sure where to focus to prevent these two problems happening again?

This topic was modified 4 months ago by Mat
Posted : 18/01/2022 12:15 am
Diem
 Diem
(@diem)
Noble Member

First stop the drafts, a heater is no fix, a screen or curtain is better.

Cheerio,

Posted : 18/01/2022 12:36 am
Mat
 Mat
(@mat-3)
Active Member
Topic starter answered:
RE: Reinstalled extruder, but now getting under-extrusion: causes?

Thanks - forgot to mention that my printer is in an enclosure. The heater was just there to prevent drafts getting in through the gaps...

Posted : 18/01/2022 2:05 pm
Diem
 Diem
(@diem)
Noble Member

I was printing a project box, and the sides had started printing but they just lifted off the base.

Bad first layer adhesion is either a poor first layer Z calibration or a dirty print-sheet.

Cheerio,

Posted : 18/01/2022 3:03 pm
Mat
 Mat
(@mat-3)
Active Member
Topic starter answered:
RE:

Bad first layer adhesion is either a poor first layer Z calibration or a dirty print-sheet.

I am not getting bad first layer adhesion! The adhesion problems I had were after about 20 layers between a 3mm bottom piece and side walls

This post was modified 4 months ago by Mat
Posted : 18/01/2022 3:06 pm
Diem
 Diem
(@diem)
Noble Member

OK, photo's?  That sounds like warping, another symptom of drafts...

Cheerio,

Posted : 18/01/2022 7:22 pm
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