Anet A8 under-extrusion via OctoPrint

What is the problem?
When printing via OctoPrint (fresh install), the flow rate is obviously lower than the "correct" amount (sparse lines). Printing via the printer directly does not have this problem.

I think I encountered similar situations before, when I 1) used Repetier to print, or 2) set "in mm^3" for "Filament" on the printer. So I suspect there could be some obvious option to fix this but I overlook.

What did you already try to solve it?


Additional information about your setup (OctoPrint version, OctoPi version, printer, firmware, browser, operating system, ... as much data as possible)

OctoPrint: Version 1.4.0;
OctoPi: The ready-to-go Raspberry Pi image with OctoPrint, Version 0.17.0, running on Raspberry Pi 3 Model B Plus Rev 1.3;
Printer: Anet A8;
Firmware: Marlin 1.1.9;
Flow rate: 100% (unchanged).
Slicer: Cura 4.5.0


Hello @freezelty!

In the Control Tab, what is the setting of Flow Rate?

It is "100%" as the default.

Have you tried in safe mode?

My gut tells me print speed might be the difference. I would look carefully at any OctoPrint/Repetier startup gcode scripts for anything that sets Fnnn.

which printer profile are you using?

What is the Gcode flavor set to in the Machine Settings in Cura?

Thanks for everyone's attention. After inspecting the previous failed and (relatively) successful prints closely in the next morning, I think Ewald_Ikemann was mostly on the correct path - the real cause was probably the damaged Teflon tube inside the hotend throat. I wanted to update you after having the printer fixed, but I just broke it more so it won't happen in a few days ...

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Personally, I cut about two inches of PTFE tubing and that's what I put in the top of my primary extruder assembly. Before, I found that off-brand filament wants to rub on the sides of a standard length of tubing and will often "notch" at the feed gear, then "air print" until I notice the problem.