Screw Stroke Calculator

Convert a documented shot volume to an ideal screw-forward stroke. Use this as a documented planning estimate, then validate it against the actual machine, mold, resin, and process.

Formula and method

Stroke = shot volume / screw cross-sectional area.

Use the machine maker screw diameter and a volume on the same material/process basis.

Inputs and units

Use controlled records, CAD, measured production data, the exact resin data sheet, or machine-maker specifications. Keep the material and time basis with the result.

Worked example

220 cm3 with a 50 mm screw gives 112.05 mm ideal stroke.

What the result supports

This result is a first-pass screen for injection unit planning. Use it to identify the next record or engineering check, not as a release decision.

Sanity check

Check the unit basis and whether all quantities describe the same cavity, shot, machine, or production window before comparing values.

Important limitation

Check non-return valve, cushion, and machine stroke limits separately.

Reference: ENGEL: machine data example.

Next calculation

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FAQ

What must be checked after using screw stroke calculator?

Retain the input source and compare this estimate with the applicable machine, mold, supplier, or production record before relying on it.