Volumetric flow

Definition

Volumetric flow Q = layer height × line width × print speed. Units are mm³/s. A typical brass 0.4 mm hotend maxes out around 8–15 mm³/s; high-flow volcano-style heaters go higher. If Q exceeds the hotend, you get under-extrusion even when e-steps are perfect. Max speed at a given layer is Q_max / (height × width).

Calculators that use this

• FDM calibration & firmware

  Maximum Volumetric Flow Rate Calculator

  Compute FDM volumetric flow Q = layer height × line width × speed, then the maximum print speed a hotend can hold at a stated mm³/s limit.

• FDM hardware & mechanics

  Nozzle Size vs Layer Limits

  Get min, typical and max FDM layer height plus min/max line width from nozzle diameter using 0.25–0.75× height and 0.9–1.5× width rules of thumb.