Plastic Extrusion Throughput Calculator
Estimate the mass throughput of a single-screw extruder from screw diameter, rotational speed and melt density (pitch ≈ D, flood-fed).
How to Use the Plastic Extrusion Throughput Calculator
- Enter the screw diameter in millimetres.
- Enter the screw speed in rpm.
- Enter the melt density for your polymer.
- Click Calculate to see mass throughput.
Use Cases
- •Quick throughput estimate for single-screw extruders.
- •Selecting screw diameter for a target output.
- •Teaching polymer processing.
Formula
Simplified drag-flow model: Q (kg/h) ≈ (π/4) · D² · RPM · 60 · ρ · 10⁻⁶, where D is the screw diameter in mm and ρ is the melt density in g/cm³.
Frequently Asked Questions
Is this a real process simulation?
No — it is a first-order drag-flow estimate for a flood-fed screw with pitch ≈ D and full channel. Back-pressure, leakage and starved feeding reduce it.
Typical melt densities?
LDPE 0.75, HDPE 0.78, PP 0.73, PVC 1.4, PET 1.2 g/cm³ at processing temperature.
What about twin-screw extruders?
Twin-screw machines are usually starve-fed and throughput is set by the feeder, not drag flow. This calculator does not apply.