fundamental problem with cura (extrusion rate)

[esopalumpa 3]

On all 3D-printer I have worked so far (even the Ultimaker), the print-speed is not limited by the head-movement, but by the maximum amount of filament the hotend can meld.

As far as I can see there is no way to specify this in Cura (other slicers can do this).

So I have to do the math by hand every time I change settings.

This is annoying.

__________

Example for a printer that can meld about 4 mm³ PLA per second:

60 mm/s speed, 0.15 mm layer height, 0.35mm extrusion-width → 3.15 mm³/s | O.K.
first layer: 0,3 mm layer height, 30 mm/s speed, 150%  initial layer line width → 4.725 mm³/s | too much

I have to reduce first layer speed to 15 mm/s.

Edited August 4, 2020 by esopalumpa

[GregValiant 435]

The formulas aren't complicated for a basic computation.  I suppose a plugin could be written with a dialog box to fill in the flow parameters and do the math in the background.  I use a simple spreadsheet and enter the parameters in a few cells and the answer shows up at the end (mm^3/sec or even E-steps/sec).  I suppose it could be considered doing it by hand because I'm using a keyboard.  That would be true of a dialog box as well.

[esopalumpa 3]

With “by hand” I meant, that it’s not done by Cura. 🙂

As in nearly all cases, the amount of filament the hotend can deliver is the limiting factor to printspeed(s), Cura should be able to handle this.

[mkoic 1]

Interesting.  

 

Does anyone know what the maximum volumetric flow rate is for an Ender 3 Pro with stock hot end?  I guess this would vary depending on nozzle size, material, printing temp … ?

Edited August 5, 2020 by mkoic