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Injection molding guide

How to Size an Injection Molding Machine

A documented workflow for checking clamp force, shot capacity, mold fit, and process limits before machine selection.

The engineering question

Start with mold geometry and complete shot definition, then check clamp force, usable injection volume, screw stroke, platen/tie-bar fit, mold height, ejection, and automation. A press that passes one calculation may fail another screen.

What to document

Use manufacturer data for the specific machine configuration; published tie-bar spacing, platen size, clamp force, injection capacity, and mold-height ranges are separate limits.

Practical workflow

Run Clamp Tonnage, Injection Unit Utilization, and Platen Fit from one documented mold/machine record.

Validation boundary

Use manufacturer documentation, grade-specific supplier data, controlled process records, and trials for any equipment, quality, material, or commercial commitment. A static calculator is a transparent starting point, not a simulation or approval.

Reference

ENGEL: machine data example