extrusionrate

Extrusion rate is the amount of material delivered by an extrusion system per unit time as it passes through a nozzle or die. It can be expressed as a volumetric flow rate (for example, cubic millimeters per second, mm^3/s) or as a mass flow rate (kilograms per second, kg/s). In plastics processing and additive manufacturing, the extrusion rate influences throughput, pressure, temperature, and final part or product dimensions.

In 3D printing, specifically fused deposition modeling, the extrusion rate describes how fast molten filament is laid down. An approximate relationship for a single path is Q ≈ v × W × H, where Q is the volumetric flow rate, v is the print head speed, W is the extrusion width, and H is the layer height. Printers regulate Q through extrusion multiplier and flow settings, and the rate is commonly reported as mm^3/s or as a percentage of the printer’s maximum capability. Calibration of the extruder steps per millimeter is used to align commanded extrusion with actual material deposition.

In industrial extrusion, the mass flow rate ṁ equals the density ρ times the volumetric flow Q (ṁ = ρQ). The rate depends on screw speed, die geometry, melt temperature, and polymer viscosity, and is often described by the material’s melt flow rate specification. Die swell, pressure drop, and heat transfer can affect the effective rate at the die exit.

Measurement and control methods include inline flow sensors and gravimetric meters. Extrusion rate is adjusted by changing drive speed, temperature, pressure, or die geometry. Accurate control is essential for product consistency, dimensional accuracy, and material properties in both conventional extrusion and additive manufacturing.