Clamping Force

The pressure applied by the injection molding machine to keep the mold closed during injection. Measured in tons (e.g., 75–500 tons).

Cavity

The hollow space in a mold where molten plastic is injected and shaped into the final part.

Core

The mold component that forms the internal surfaces of a molded part. It works in conjunction with the cavity to shape the part.

Cycle Time

The total time required to complete one injection molding cycle, including injection, cooling, and ejection of the part.

Draft Angle

A slight taper added to the walls of a molded part to facilitate easy removal from the mold.

Ejector Pins

Mechanical components that push the finished part out of the mold once it has solidified and cooled.

Flash

Excess plastic that seeps out of the mold cavity and solidifies, often found along parting lines. It typically requires trimming.

Gate

The entry point through which molten plastic flows into the mold cavity. Gate design affects the flow and quality of the part.

Hot Runner

A mold system where the plastic remains molten in the runner system. Helps reduce material waste and cycle time.

Injection Unit

The part of the machine that melts and injects plastic into the mold. It includes the hopper, barrel, screw, and nozzle.

Mold

A custom-designed tool made of metal (typically steel or aluminum) that contains the cavity and core. It shapes the plastic during the molding process.

Parting Line

The line on a molded part where the two halves of the mold meet. Flash often occurs along this line.

Resin

The raw plastic material, typically in pellet form, that is melted and injected into the mold.

Runner

The channel that guides molten plastic from the sprue to the gate(s) and into the cavity.

Shot Size

The volume or weight of plastic injected into the mold during one cycle. Measured in ounces or grams.

Sink Mark

A surface depression caused by uneven cooling or shrinkage, typically found in thick sections of a molded part.

Sprue

The main channel through which molten plastic enters the runner system from the injection nozzle.

Specific Gravity

The density of a plastic material compared to water. Used in shot size and material selection calculations.

Thermoplastic

A type of plastic that becomes pliable when heated and hardens upon cooling, allowing for reshaping and recycling.

Vent

A small channel that allows air to escape from the mold cavity during injection, preventing voids and burn marks.