Volumetric flow is a concept that relates to how much material a 3D printer can extrude in a given time. It is usually measured in cubic millimeters per second (mm³/s) and depends on factors such as the nozzle diameter, the extrusion temperature, and the type of filament being used.

Volumetric flow is important for 3D printing because it affects both the quality and the speed of the printing process. If the volumetric flow is too low, the printer may not be able to fill the gaps between the layers, resulting in weak or incomplete prints. If the volumetric flow is too high, the printer may over-extrude, causing blobs, stringing, or clogging.

To achieve optimal volumetric flow, one needs to calibrate the flow rate (also known as extrusion multiplier) in the slicer settings. This is a factor that adjusts how much filament the printer pushes through the nozzle. The flow rate can be calibrated by printing a test object with known dimensions and measuring its actual dimensions with calipers. The flow rate can then be adjusted until the measured dimensions match the expected ones.

Alternatively, one can use a volumetric flow calculator to estimate the optimal flow rate based on the nozzle diameter, the filament diameter, and the maximum extrusion temperature. This can save time and material by avoiding trial-and-error prints. However, this method may not account for variations in filament quality or environmental conditions, so it is recommended to verify the results with a test print.

Volumetric flow is also relevant for volumetric 3D printing, a technique that creates objects by solidifying a whole resin volume with light beams. This method can produce complex shapes with high resolution and smooth surfaces without requiring support structures or layer-by-layer fabrication. However, this method also requires precise control of the volumetric flow rate to avoid over- or under-exposure of the resin.