High-Precision FHG Series Plastic Injection Molding Machine from China Suppliers and Factory
Injection Unit
Injection Unit
Injection Unit — Detail 01
Injection Unit — Detail 02
Frequently Asked Questions
Q1
What is an injection unit in an injection molding machine?
The injection unit is the core component of an injection molding machine responsible for melting plastic material and injecting it into the mold cavity under controlled pressure and speed. It typically consists of a hopper, barrel, screw, and nozzle.
Q2
What are the main functions of the injection unit?
The injection unit performs three main functions: plasticizing (melting) the raw plastic material, metering the correct shot volume, and injecting the molten plastic into the mold at the required pressure and speed to ensure complete and accurate part formation.
Q3
How does the screw design affect injection unit performance?
The screw geometry — including its length-to-diameter ratio, compression ratio, and flight depth — directly influences plasticizing efficiency, melt homogeneity, and injection speed. Specialized screw designs are available for different materials such as PVC, engineering plastics, or highly filled compounds.
Q4
What materials can be processed by the injection unit?
Modern injection units are designed to process a wide range of thermoplastic materials including ABS, PP, PE, PC, PA (Nylon), POM, PET, TPU, and various engineering-grade and glass-fiber-reinforced resins. Material-specific barrel and screw configurations ensure optimal processing conditions.
Q5
How is injection pressure controlled in the injection unit?
Injection pressure is precisely controlled through a closed-loop hydraulic or servo-electric drive system. Sensors monitor real-time pressure and position feedback, allowing the machine controller to dynamically adjust injection speed and pressure profiles for consistent part quality.
Q6
What maintenance is required for the injection unit?
Regular maintenance of the injection unit includes periodic inspection and replacement of the screw, barrel, and check ring for wear; cleaning of the barrel during material changeovers; lubrication of moving components; and checking the nozzle and heater bands for proper function to ensure long-term reliability and consistent performance.