Small Injection Molding Mold: Analysis of Basic Structure

An understanding and analysis of currently produced small plastic injection molds reveal that they share a set of common structural components, which include:

Molding Components of the Plastic Injection Mould

This refers to the parts that are in direct contact with the plastic part and form the internal and external surfaces of the molded product. These components include the cavity, inserts, and core. During operation, they shape the inner and outer geometry of the molded piece. When the mold is closed, a complete mold cavity is formed for molding.

Gating System of the Injection Molding Mold

This section refers to the flow channel through which molten plastic travels into the mold cavity. It typically includes the main runner, sub-runner, gate, and cold slug well. Its functions during the molding process include venting, guiding the molten plastic into the cavity, controlling overflow, and monitoring the mold pressure.

Guiding Components of the Plastic Injection Molds

The guiding system is positioned between the moving and fixed halves of the mold and ensures accurate alignment and positioning. To meet practical needs, guiding mechanisms can adopt either the guide pillar and bushing method or the external taper alignment method. For small plastic injection moulds, external taper alignment is commonly used.

Core-Pulling Mechanism of the Plastic Injection Mould

This part enables the movement of side core blocks or core inserts and usually consists of angled guide pillars, angled sliders, and curved pins. In the design of small plastic injection molds, side core-pulling is typically realized using angled sliding blocks to achieve the required lateral motion.

Ejection System of the Injection Molding Mold

The ejection system is used to eject the formed plastic part from the mold. It includes components such as ejector pins, ejector plates, and return pins. It's important to enhance the design of the ejection system and guiding columns to ensure smooth operation and adequate rigidity to meet technical standards.

Temperature Control System of the Plastic Injection Mould

The temperature control unit comprises heating and cooling elements used to regulate mold temperature, ensuring the molded product has the desired surface quality and dimensional accuracy.

Venting System of the Plastic Injection Molds

The purpose of the venting system is to expel trapped air and gases from the mold cavity to avoid defects in the final plastic part. Effective venting is often achieved by machining vent grooves on the parting surface or by utilizing natural clearances between mold components. The design method should be chosen based on the actual structure of the small injection molding mold and the production requirements of the plastic parts.

Supporting Components of the Plastic Injection Mould

Supporting elements are used to provide structural reinforcement, resist pressure and elastic deformation. To ensure proper support, their strength and stiffness must be carefully engineered to withstand operational loads and meet real-world application needs.