OctoPrint to extrude 10 cm

[gauthier 0]

I am trying to use Octoprint on my Ultimaker 2+, in order to perform my extruder's estep calibration.

 

When I try to extrude 100 mm, only about 35 mm are extruded. I guess there is something I missed when setting up the machine in Octoprint, what could it be?

 

The octoprint terminal says: 

Send: G91
Recv: ok
Send: M83
Recv: ok
Send: G1 E100 F300
Recv: ok
Send: M82
Recv: ok
Send: G90
Recv: ok

 

Edited December 6, 2021 by gauthier
more gcode

[tinkergnome 927]

2 hours ago, gauthier said:

When I try to extrude 100 mm, only about 35 mm are extruded. I guess there is something I missed when setting up the machine in Octoprint, what could it be?

 

If my calculator is right, you try to extrude more than 30mm³ per second. Are you sure that your printer can handle this?

That's nearly 8 times more - compared to the feedrate in the linked article.

Don't forget that these instructions are made for a much smaller filament diameter (1.75mm).

 

What happens, if you choose a more reasonable feedrate (e.g. F40 instead of F300)?

 

 

[ahoeben 1,955]

Good thinking @tinkergnome! And here I was caught up in the fact that 100 / 35 is about equal to the filament diameter, and I could not figure out why/how that mattered 😉

[gauthier 0]

12 hours ago, tinkergnome said:

What happens, if you choose a more reasonable feedrate (e.g. F40 instead of F300)

 

Right! There is a flow rate field just below the extrude control in the octoprint dialog. I tried to set it to 20 %, but it somehow wouldn't bite. 

 

On the other hand I didn't want to believe in that, because I would expect the extruder to skip if that was the case. It felt smooth and silent. Was that a wrong assumption? 

Edited December 7, 2021 by gauthier

[tinkergnome 927]

1 hour ago, gauthier said:

On the other hand I didn't want to believe in that, because I would expect the extruder to skip if that was the case. It felt smooth and silent.

 

first comes slipping - and it starts long before skipping

I think, that's what happened.

(please - don't quote me outside of this context 😛)

 

• 35 mm filament length corresponds to a volume of approx. 220 mm³
• the extrusion lasted for 20 seconds - that means approx. 11 mm³ per second
• and 11 mm³ per second is very near the maximum extrusion rate the UM2 can achieve (depending on material, temperature and nozzle diameter)
• only circumstantial evidences - but still...🙂

 

 

 

[gauthier 0]

You were right! I solved it that way:

 

And got 104.5 mm. 

 

Thanks! 

[marcel-klapwijk 0]

For anyone visiting this topic looking for the solution/setting this is what I did, following the all3dp instructions, but measuring at the end of them bowden tube (cutting the filament flush):

- m503 => E282.00

- G1 E100 F100 => 72mm

- 282 / 72 = 3.9166  => new value for E in printer profile = 390

- G1 E100 F100 => 103mm

- 390 / 102 = 3.8235  => new value for E in printer profile = 380

 

Measuring at the bowden end, is a bit less accurate since there is about 1mm play in it, but it is much more convenient when the machine is loaded with black PLA.