Definitions
Volumetric flow rate (mm³/s) is the throughput of filament out of a HotEnd. The max volumetric flow rate is the limit at which the requested volume of filament is able to be reliably extruded. Beyond this point under extrusion occurs, resulting in compromised/ failed prints.
Volumetric flow rate is filament and temperature-dependent. Generally speaking, the lower the viscosity of the material the higher the possible flow rate. On a related note, most materials used in FDM 3D printing become less viscous the higher the printing temperature you are using.
Just because a hot end is advertised with a specific flow rate, it doesn't mean your setup will be able to fully utilise that figure! - part cooling, motion system rigidity, and electronics will all impact the final result.
1. Calculating the Area
When comparing flow rate data from different manufacturers pay attention to how they have calculated their flow rate value. We look at the same calculation that slicers commonly use, however, there is a simpler (less realistic) value that is often used.
Beware of manufacturers who use the following: Volumetric flow rate (mm³/s) = speed (mm/s) x Extrusion width (mm) x Layer height (mm)
The most accurate theoretical calculation for volumetric flow rate assumes the cross-section of the track is a stadium. - Below is the calculation we recommend.
Area of a stadium = π × r2 + 2 × r × a
a = w - h
r= layer height / 2
w= track width
h= layer height
Volumetric flow rate calculator
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height