China FHG PET Injection Molding Machine 100ton-650ton - Reliable Factory Suppliers for Efficient Production

The injection unit is responsible for melting the plastic material and injecting it under high pressure into the mold cavity. It controls the temperature, speed, and pressure of the melt to ensure consistent and high-quality part production.

The main components include the hopper, barrel, screw, heater bands, nozzle, and the injection cylinder. Each component plays a critical role in the plasticizing and injection process.

The screw geometry — including its length-to-diameter ratio, compression ratio, and flight depth — directly influences the melting efficiency, mixing quality, and plasticizing capacity. Selecting the right screw design is essential for processing different types of plastic materials.

The injection unit can process a wide range of thermoplastic materials such as PP, PE, ABS, PC, PVC, Nylon, and more. Special screw and barrel configurations are available for engineering plastics and high-temperature materials.

Injection pressure is precisely controlled through the hydraulic or servo-driven system, which regulates the force applied to the screw during the injection phase. Modern machines use closed-loop feedback systems to maintain accurate and repeatable pressure profiles.

Regular maintenance includes purging the barrel when changing materials, inspecting and replacing worn screws and barrels, checking heater band functionality, verifying nozzle condition, and lubricating moving parts as recommended by the manufacturer. Consistent maintenance ensures long service life and stable production quality.