Injection Molding Glossary
A-C
Abrasion: Resistance of a material to surface wear caused by rubbing or friction.
Air entrapment: Entrapped air in a liquid or plastic which can cause visible voids or weak spots in the finished parts.
ANSI: American National Standards Institute
API: American Petrolium Institute
Barrel : The chamber in which the material is heated. It is aroundat the end of the nozzle and will also contain the screw.
Boss: A raised feature that projects outward from a mould as a means of fastening two parts together.
Burn Score: The number of layers a plastic must be exposed to flame in order to burn through
Cavity: A negative image of part to be injected into the mould.
Clamp Force: The maximum force the toggle type injection molding machines are capable of providing.
Clamping Plate: A plate which clamps the mould halves together during the injection moulding process.
Cold Run: A run of material without heat or pressure.
Compression Fitting/Molding: The process used to join two pieces together with a rubber or plastic seal.
Cooling: The process used to dissipate the heat created by the injection process.
Co-moulding: A process in which two materials are simultaneously injected into a mould.
Cored Out: A process used to remove sections of material from a completed moulded part.
Draft: Sloping of internal mould surfaces to assist in the release of a finished part on ejection.
Dry Cycle: A cycle without material, used to determine the time taken to open and close the moulds in an injection moulding machine.
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E-I
Ejector Pin: A pin that is used to remove a moulded part from a mould.
Flow lines: A series of parallel striations visible due to imperfections in the flow of the material.
Gate: The place on the mould where the material enters.
Hub: The section of the mould where molten plastic is injected.
Injection Moulding: Injection moulding is a process used to produce parts by injecting molten plastic into a pre machined mould.
Knobs: Features designed around a mould to assist in releasing the completed part.
Melt: The plastic before it is injected into the mould.
Nozzle: The tip at the end of the barrel through which the plastic is injected into the mould.
Overmould: When one material is injected over the top of another.
Parting Line: The line visible at the join of the two mould halves.
Pneumatic: The use of air pressure to assist in injection of the material into the mould.
Runner: The path that the molten plastic follows to get to the mould cavity.
Screw: A hollow rod that is used to inject the material into the mould.
Shrinkage: The decrease in size that occurs to a material or moulded part due to cooling.
Sprue: The entrance gates from the runners of the mould.
Tear Strength: The amount of force or stress that a material can tolerate before it fractures.
Thermoset: Plastics which become chemically and permanently altered when heated, cannot be remelted.
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Thermoplastic: Plastics which can be remelted and reformed.
Toggle Type: Injection moulding machines with two or more mechanical arms that move in an opposite trajectory and are used to clamp the mould.
Undercut: A feature of a part where the material cannot be ejected without slightly altering the shape of the part.
Vent: A shallow hole or passage between the two mould halves used to release air.
Volatile Organic Compounds (VOCs): Gases and fumes emitted from the molding material that can affect air quality.
Warpage: Deformation or displacement of a material or moulding caused by shrinkage or uneven cooling.
Water Line: A pipe that carries water to the machine for cooling purposes.
