Extrudate calculation

[g0ultimaker 0]

Hello,

I’m doing some research on Cura with my Ultimaker² momentarily on how it calculates the amount of extrudate, E-values.

I saw a topic on extrudable.me about how to calculate the difference between the expected volume and the extruded volume. http://www.extrudable.me/2013/11/03/slic3r-strange-defaults-causing-qu-bd-woes/

But if a do so the expected and extruded volumes don’t match up (see figure).

What am I doing wrong?

 

 

The g-code is some lines from: UM2 - Extrusion Test - NoRet - 3-10mm3.gcode

With I belief a width of 0,4 mm (nozzle size) and a layer height of 0,25mm.

My formulas are in yellow.

Can anyone explain where the difference comes from?

 

[illuminarti 16]

There's a couple of things going on here. Firstly, UltiGcode E-coordinates are in cubic mm, not linear mm of filament fed in. Secondly, you're running the calculation on the first layer, which is only 0.2mm thick, not 0.25 like the rest of them.

If you adjust for those things, that should get the numbers where they are supposed to be.