Family mold

Where it comes up

• Plastic injection moldingMolten thermoplastic injected into a steel or aluminum mold. Lowest piece price for plastic parts at 5,000+ a year.

Related terms

Cavity

A cavity is the hollow in a mold that forms the part's shape, typically the outside or cosmetic side. A mold may have one cavity or many; a 4-cavity mold makes four parts per cycle. More cavities raise tooling cost and lower piece price.

Short shot

A short shot is an injection molded part that is incomplete because plastic froze before filling the whole cavity. Causes include low shot size or pressure, blocked vents, thin walls, and long flow lengths. Molders often run short shots on purpose during mold trials to study fill.

Bridge tooling

Bridge tooling is lower-cost, faster tooling, often aluminum or unhardened P20 steel molds and soft dies, used to make production-intent parts while hardened production tooling is built. It covers pilot builds, launches, and early sales at volumes from hundreds to tens of thousands of parts.