Injection Molding

Here at Quickparts, we are in constant contact with engineers, mold makers, machinists, and other self-proclaimed experts of the manufacturing industry. Over the years, our molding lexicon has grown tremendously – to a “molding urban dictionary” of sorts. Listed below are some of the most common terms that frequent our ears daily.

What did we miss? We challenge you to send us your most creative synonyms!

Cavity Refers to the upper half of the injection mold usually the show surface of the finished product but is mainly concave
Core Refers to the side of the tool where the plastic part is injected from; also known as the bottom half of the tool
Gate Refers to where the plastic enters into the cavity of the mold.
Hand Load Aluminum or steel feature in a mold used to create undercuts in molded parts.  They are manually removed from the mold during the part ejection process.
Heel Refers to the portion of an automatic custom injection mold that keeps the slide in the forward position when the molding machine is closed on the mold
Horn Pin Pin used to actuate the slide on an automatic injection mold
Runner A channel cut into custom injection molds, in which plastic travels from the injection molding machine, through the sprue, through the runner and then through the gate ultimately filling the part
Shear Refers to when plastic enters into the mold and the melt is maintained by friction produced by speed and pressure. Too much shear can cause the plastic material to burn, too little can cause the material to freeze off causing short shot
Side Action Term used for slides and/or hand pulls used in the injection mold build process
Vestige Material protruding from the gate area after gate runner has been removed from the injection molded part. This vestige is usually trimmed by the molding machine operator