Glossary

The shaped void in a mold where molten plastic forms each part during the injection cycle.

The tonnage required to keep an injection mold closed against melt pressure during fill, pack, and hold.

Unwanted thin plastic that leaks past the mold parting line during fill or pack.

The narrow entry point where melt flows from the runner into the cavity.

Post-fill pressure that packs the cavity and compensates for shrinkage as the part solidifies.

A lab measurement of polymer flow rate that indicates how easily a resin fills thin or long mold features.

The interface where mold halves meet; projected area here drives clamp-force requirements.

Channels that carry melt from the machine nozzle to each gate: cold, hot, or insulated designs.

How much a molded part contracts after fill: drives cavity oversize and hold-pressure settings.

Shallow channels or gaps that let trapped air exit the cavity during fill.

The junction where separate melt fronts merge, often weaker and more visible than surrounding material.