Category Archives: Mold Components

Cavity and Core

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This article describes the cavity and core, its processing method, and its arrangement into the mold. More reference like this are described in Mold-Making Handbook

Cavity and core

cav-core

Core and cavity can be classified into 2 methods, integrated and nested method. You can choose which method will define your cavity and core.

Integrated: When the molded part is formed directly by the die.

Nested: When the molded part is formed by the die components.

Nested Cavity and Core

Benefits:

  • There is no restriction to the geometry of the molded part. Processing efficiency can be done when components are separated.
  • Mold materials can selected for better wear resistance and temperature control.
  • Damaged components can be replaces easily and cost effectively.

Mold-Making Handbook
Engineering References)

Functions of Mold Base Parts

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moldpartsFixed Clamping Plate
Holds The fixed side of the mold to the fixed platen of the injection machine.

Locating Ring
It is used to locate the center of the injection machine so that the sprue bushing and the nozzle are aligned. Commonly fitted into the counterbore in the fixed clamping plate.

Fixed Cavity Plate
Used to hold the fixed cavity block, leader pin/bushing, and sprue bushing.

Movable Cavity Plate
Used to hold the movable cavity block, leader pin/bushing.

Movable Clamping Plate
Holds The movable side of the mold to the movale platen of the injection machine.

Spacer Block
Mounted between the movable clamping plate and the movable cavity plate to give space and allow the ejector plate to move when ejecting the
part.

Ejector Retainer Plate
Holds the ejector pins and the return pins in place.

Ejector Plate
Pushes the ejector pins and return pins at the same time. Mounted to the ejector retainer plate to form the ejector unit.

moldparts1Support Pillars
Bars placed between the spacer blocks to give additional support to the movable cavity plate.

Sprue Bushing
Has a tapered hole through which the material is forced into the runner. It is butted up against the nozzle of the injection machine.

Return Pins
Same as ejector return pins. Make sure that the ejector unit is back in its original position when the mold closes.

Leader Pins and Bushings
Precisely align the two halves of the mold base (fixed and movable).