High-Precision FHG Series Plastic Injection Molding Machine from China Suppliers and Factory
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Injection Unit

Injection Unit

Injection Unit — Detail 01

Injection Unit — Detail 02
Frequently Asked Questions
Q
What is the main function of an injection unit in a molding machine?
The injection unit is responsible for melting raw plastic material and injecting it under high pressure into the mold cavity. It controls the precise volume, speed, and pressure of the injected material to ensure consistent part quality.
Q
What are the key components of an injection unit?
The main components include the hopper, barrel, reciprocating screw, heater bands, nozzle, and hydraulic or electric drive system. Each component plays a critical role in the plasticizing and injection process.
Q
How does injection pressure affect the final product quality?
Injection pressure directly influences how completely the mold cavity is filled. Insufficient pressure can cause short shots or sink marks, while excessive pressure may lead to flash, warping, or internal stress in the finished part.
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, PA, and engineering-grade plastics. The barrel and screw configuration may vary depending on the material being processed.
Q
How is the injection unit maintained to ensure long service life?
Regular maintenance includes purging the barrel when changing materials, inspecting and replacing worn screw and barrel components, checking heater bands and thermocouples, and lubricating moving parts according to the manufacturer's schedule.
Q
What is the difference between a hydraulic and an electric injection unit?
Hydraulic injection units use oil-driven cylinders and are known for high force output, making them suitable for large-tonnage machines. Electric injection units use servo motors for direct drive, offering higher precision, energy efficiency, faster response, and cleaner operation — ideal for medical and precision applications.






