Classification of Injection Molds
Injection molds can be categorized in various ways, including structural design, runner system, cavity count, ejection method, and product processing characteristics.
1. Classification by Mold Structure
Two-plate mold:
The most common mold type, consists of a moving half and a fixed half. It features short cycle times and a simple structure, suitable for most standard products.
Three-plate mold:
Adds an intermediate parting plate to the two-plate design. Ideal for products requiring complex gating systems or side core-pulling mechanisms, enabling easier post-processing and trimming.
Multi-plate mold:
Includes four-plate, five-plate molds, etc., used for multi-cavity molds where special requirements exist for part geometry, assembly, or secondary processing during parting and ejection.
2. Classification by Runner System
Cold runner mold:
Uses a cooled runner system where the runner solidifies with the part. Cost-effective and widely used, but may leave visible gate marks.
Hot runner mold:
Employs heated runners to keep plastic molten, minimizing material waste and improving surface quality. Ideal for high-precision or cosmetically demanding products.
3. Classification by Cavity Count
Single-cavity mold:
Produces one part per cycle, suitable for prototyping, low-volume production, or high-precision applications.
Multi-cavity mold:
Produces multiple identical parts per cycle (standard multi-cavity) or different parts (family mold). Boosts efficiency and reduces per-unit costs but requires complex design and manufacturing.
4. Classification by Ejection Method
Ejector pin mold:
Uses pins to eject parts, ideal for simple geometries without undercuts.
Side core-pulling mold:
Incorporates side-action mechanisms to eject parts with internal/external protrusions or complex features.
Insert mold:
Designed for parts requiring embedded metal components or pre-assembled inserts, which are positioned and molded into the part during injection.
