Updated November 3, 2026.
Injection molding machine tonnage and shot weight cannot be directly converted. Tonnage describes clamping force; ounces in a machine specification commonly describe shot weight. They measure different physical quantities. A statement such as “55T equals 4 oz” is not a universal conversion rule.
Read the Specification Units Separately
| Specification | What it describes | What to request |
|---|---|---|
| Clamping force: kN or tons | The clamping unit’s rated force | Force rating and the supplier’s ton-force convention |
| Shot weight: g or oz | A mass rating for a stated reference material | Reference polymer, screw option and usable shot range |
| Shot volume: cm³ or in³ | Displacement associated with the injection unit | Screw diameter, stroke and the definition used in the datasheet |
Why the Same Tonnage Can Have Different Shot Ratings
Machine specifications can offer different injection units and screw diameters with the same clamping unit. ARBURG’s published technical data, for example, lists clamping force separately from injection unit, screw diameter, displacement and shot weight. This illustrates how to read a datasheet; it does not establish MINHUI model specifications.
A PS-based shot-weight rating is not automatically the usable shot mass for PVC, TPE or another resin. The material, injection-unit configuration and intended operating range must be considered in the equipment review.
A Practical Selection Checklist
- Confirm the part drawing, cavity count, runners and exact material grade.
- Have the tooling/process review establish the required clamp force and margin.
- Check injection capacity, pressure, flow and material residence requirements separately.
- Verify mold dimensions, mold height, opening stroke, handling access and table configuration.
- Request a quotation that names the injection unit and screw option rather than only the tonnage.
PVC-specific screw or coating requirements should be agreed against the resin supplier’s processing information and the proposed equipment. There is no single screw diameter or geometry guaranteed by an ounce rating.
Use the published standard machine and rotary table machine data as equipment references, then confirm the selected configuration.
