Injection molding can be a complex industry to understand. However, some of the processes and terminology don’t necessarily have to be to those unfamiliar to what it is and how it’s done.

Here’s a quick glossary of some of the most commonly used terms in our industry to help you become more familiar with what we do and how we do it.

Barrel

On an injection-molding machine, this component is where the resin pellets are melted before being injected into the sprue and runner system of the mold.

Boss

This refers to a protrusions on molds and/or plastic parts.

CAD

This translates to “computer-aided design.”

Core

The moveable B Half half of the tool, this is the side where the plastic part is Ejected.  

Draft

EjectionIn order to keep the part from being scraped during ejection, a draft is a taper on the face of the part that prevents it from being parallel to the motion of the mold opening.

This is the final stage of injection molding processes, in which the part is ejected from the mold by pins or other mechanisms.

Flow Marks

Flow Marks are visible marks on the part that show where two flow fronts of plastic come together in the mold before it solidifies.

Gate

This refers to the spot where the plastic enters into the mold’s cavity. Automatically Trimmed Gates are features in the tool that break the gate when the molding tool opens to eject the new part. Manually Trimmed Gates require an operator to separate parts from runners.

Injection

Forcing liquefied resin into a mold to form a part.

Resin

The resin or plastic is the name for the chemical plastics that are injected and form the plastic part.

Runner