High-Precision FHG Series Plastic Injection Molding Machine from China Suppliers - Reliable Factory Solutions
Injection Unit
★ Key Component
Injection Unit — Overview
Injection Unit — Detail View 1
Injection Unit — Detail View 2
Frequently Asked Questions
Q
What is an injection unit in an injection molding machine?
The injection unit is a core component of an injection molding machine responsible for melting plastic material and injecting it into the mold cavity under high pressure. It typically consists of a hopper, barrel, screw, and nozzle.
Q
What are the main functions of the injection unit?
The injection unit serves three primary functions: plasticizing (melting the raw plastic material), metering (measuring the correct shot volume), and injecting (pushing the molten plastic into the mold at controlled speed and pressure).
Q
How does the screw design affect injection unit performance?
The screw geometry — including its length-to-diameter ratio, compression ratio, and flight depth — directly affects plasticizing efficiency, melt homogeneity, and injection pressure. A well-designed screw ensures consistent melt quality and stable shot weight.
Q
What materials can be processed by the injection unit?
Injection units are designed to process a wide range of thermoplastic materials including PP, PE, ABS, PC, POM, Nylon, and engineering-grade resins. The barrel and screw materials are often selected based on the abrasiveness and corrosiveness of the processed resin.
Q
How is injection pressure controlled in the injection unit?
Injection pressure is controlled through the hydraulic or servo-electric drive system. Modern machines use closed-loop feedback control to precisely regulate injection speed, pressure profiles, and hold pressure during each molding cycle.
Q
How should the injection unit be maintained for optimal performance?
Regular maintenance of the injection unit includes purging the barrel when changing materials, inspecting the screw and barrel for wear, checking the non-return valve for leakage, lubricating moving parts, and calibrating temperature sensors to ensure accurate barrel heating.