process conditions of temperature, pressure and time, and automatically
making any changes required to keep part production within preset
tolerances.
Cooling Channels: Channels located within the body of a mold through
which a cooling medium is circulated to control the mold surface temperature.
Cushion: Extra material left in barrel during cycle to try and ensure that the
part is packed out during the hold time.
Cycle: The complete sequence of operations in a process to complete one
set of moldings. The cycle is taken at a point in the operation and ends when
this point is again reached and moving platens of the clamp unit in the fully
open position.
Cycle Time: The time required by an injection molding system to mold a part.
Dwell: A pause in the applied pressure to a mold during the injection cycle
just before the mold is completely closed. This dwell allows any gases formed
or present to escape from the molding material.
Ejector Pins: Pins that are pushed into a mold cavity from the rear as the
mold opens to force the nished part out of the mold. Also called knockout
pins.
Ejector Return Pins: Projections that push the ejector assembly back as the
mold closes. Also called surface pins or return pins.
Ejector Rod: A bar that actuates the ejector assembly when the mold opens.
Family Mold: A multi-cavity mold where each of the cavities forms one of the
component parts of an assembled nished part.
Fleeting angle: The angle at which the belt enters and exits the pulleys; it
equals the sum of the parallel and angular misalignments.
Fill: The packing of the cavity or cavities of the mold as required to give a
complete part or parts that are free of ash.
Flow: A qualitative description of the uidity of a plastic material during the
process of molding. A measure of its moldability generally expressed as melt
ow rate or melt index.
Gate: An opening through which the melt enters the mold cavity.
Hot Tip Gate: An injection molding method that uses a heated gate on the
A-side of the part to eliminate the creation of any runner or sprue. The gate
vestige will be a small sharp bump that can be trimmed if necessary.
Hot Runner Mold: A mold in which the runners are insulated from the chilled
cavities and are kept hot. Hot Runner molds make parts that have no scrap.
Inseal: Inlet seal
Injection: The process of forcing melted resin into a mold.
Injection Pressure: The pressure on the face of the injection screw or ram
when injecting material into the mold, usually expressed in PSI or BAR.
Knockout Pins: A rod or device for knocking a nished part out of a mold.
Land: The walls of the gate, parallel or angled to the molding surface.
21-2
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GLOSSARY OF TERMS
Hot Runner User Manual
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