Injection Molding

Injection molding is a shaping process in which thermoplastic material is fed into a heated barrel, mixed, and forced into a mold cavity where it cools and hardens to the configuration of the mold cavity.  Injection molding is used to produce more thermoplastic products than any other process.  In some circumstances, thermoset plastics can also be used with injection molding.

Process Characteristics

Utilizes a  ram or screw-type plunger to force molten plastic material into a mold cavity
Produces a solid or open-ended shape conforming to the mold cavity
Uses thermoplastic or thermoset materials
Produces a parting line and sprue and gate marks
Ejector pin marks are usually present

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Information provided is from Manufacturing Processes Reference Guide by Robert H. Todd, Dell K. Allen, and Leo Alting.--1st ed. Published by Industrial Press Inc., 1994.