The injection molding series can be divided into three main dimensions: molding process type, raw material attributes, and equipment structure, covering all scenario needs from basic general to high-end precision. Below is a detailed introduction to the mainstream types:
🔧 Classified by molding process
This is the most commonly used classification method in industrial production, where different processes correspond to different product requirements:
Ordinary conventional injection molding is a general type based on :***, where thermoplastic plastic is melted and then injected under high pressure into molds to cool and form. The equipment is simple and low-cost, suitable for mass production of everyday necessities such as plastic basins, toys, and ordinary appliance shells.
Precision injection molding: Focusing on ultra-high precision, product dimensional accuracy can reach below 0.01mm, with extremely high requirements for equipment, molds, and processes. Further segments include micro-foamed precision injection molding and injection compression molding, suitable for high-precision parts such as mobile phone frames, medical syringe cylinders, and precision gears.
High-speed injection molding: By increasing injection speed, the molding cycle is greatly shortened, resulting in extremely high production efficiency. It is specially designed for simple, high-demand single-use products such as takeout lunch boxes, milk tea cup lids, and thin-walled packaging.
Gas-Assisted Injection Molding: Injects high-pressure nitrogen during the plastic filling process to form a hollow structure inside the product, effectively solving shrinkage marks and bubbles in thick-walled parts, saving up to 50% of raw materials, suitable for automotive bumpers, refrigerator panels, large table and chair armrests, and other thick-walled complex parts.
Dual-color/multi-color injection molding: Multiple barrels are used to simultaneously inject plastics of different colors and materials into the mold, achieving a hard + soft adhesive composite effect in one go, without the need for subsequent splicing. Commonly found in products such as non-slip toothbrush handles, two-tone car buttons, and colored headphone shells.
Insert Injection Molding: Before injection molding, inserts such as metal and rubber are pre-placed into molds. After injecting plastic, the material is integrated, giving the plastic parts thread and conductive functions. Typical applications include metal inserts for electrical plugs and mobile phone antenna mounts.
Foam injection molding: Foaming agents are added to plastic melts, forming a porous structure inside the product after molding, significantly reducing weight, while also providing shock absorption and heat insulation. It is widely used in automotive interior cushioning parts, packaging foam pads, and lightweight aerospace structural components.
Thermosetting injection molding: uses phenolic resin and other thermosetting raw materials, which are insoluble and non-melting after molding. They feature high temperature resistance, corrosion resistance, and high strength, specifically designed for industrial parts in special high-temperature environments.
🧪 Classified by raw material attributes
From the perspective of core raw materials used in injection molding, they can be divided into two basic categories:
Rubber injection molding: Rubber is directly injected into molds for vulcanization and molding. The molding cycle is short, labor intensity is low, and product quality is uniform and stable. It is widely used in rubber seals, shock-absorbing rubber accessories, and other products.
Plastic injection molding :*** The mainstream type of injection molding, using thermoplastics such as polyethylene, polypropylene, ABS, and PA as raw materials. After cooling and molding, various plastic parts are obtained, covering over 90% of residential and industrial plastic product scenarios.
📦 Classified by injection molding machine structure
Different injection molding machine structures correspond to different production scenarios:
Hydraulic injection molding machine: The earliest classic model, relying on a hydraulic system to provide large-tonnage driving force. It has a mature structure and low maintenance costs, suitable for large automotive parts, home appliance housings, and other large-sized plastic parts.
Fully electric injection molding machine: Driven by a fully servo motor, no hydraulic oil contamination, with repeat positioning accuracy reaching ±0.01mm, offering high precision and low energy consumption, suitable for medical cleaning products and high-end precision electronic components.
Electro-hydraulic mixed injection molding machine: Combines large-tonnage hydraulic capability with precise control of servo motors, achieving energy savings of 20%-50%. Its cost is between hydraulic and fully electric models, making it the mainstream general-purpose model in current industrial manufacturing.
Vertical injection molding machine: The injection and mold-closing mechanisms are arranged vertically, with mold opening and closing directions vertically, making it especially convenient for placing metal inserts. It occupies little space and is mostly used for small plastic parts with inserts such as electronic connectors and electrical switches.