China FHG Series PET Injection Molding Machine 100ton-650ton – Top Suppliers and Factory for Efficient Production
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01 Injection Unit
Injection Unit — View 1
Injection Unit — View 2
Injection Unit — View 3
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Frequently Asked Questions
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Q What is an injection unit in an injection molding machine?The injection unit is the core component responsible for melting plastic pellets and injecting the molten material into the mold cavity under high pressure. It typically consists of a hopper, barrel, screw, and nozzle working together to ensure precise and consistent material delivery.
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Q What are the key performance indicators of an injection unit?Key performance indicators include injection pressure, injection speed, shot capacity, screw diameter, plasticizing capacity, and L/D ratio (length-to-diameter ratio of the screw). These parameters determine the range of materials and part sizes the machine can handle.
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Q How does the screw design affect injection unit performance?The screw design directly impacts plasticizing efficiency, melt homogeneity, and shear heat generation. Different screw geometries are optimized for specific materials such as PVC, nylon, or engineering resins, ensuring better melt quality and faster cycle times.
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Q What maintenance does the injection unit require?Regular maintenance includes inspecting and replacing barrel and screw wear components, cleaning the nozzle and check ring, monitoring heater bands and thermocouples, and lubricating moving parts. Preventive maintenance schedules help extend service life and maintain consistent shot quality.
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Q What materials can be processed by a standard injection unit?A standard injection unit can process a wide range of thermoplastics including PP, PE, ABS, PS, PC, nylon (PA), POM, and more. Special configurations with bimetallic barrels or corrosion-resistant screws are available for processing glass-filled, flame-retardant, or highly abrasive materials.
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Q How do I choose the right injection unit size for my application?Selecting the correct injection unit size depends on the shot weight of your part, the type of resin used, required injection speed and pressure, and cycle time targets. As a general guideline, the shot weight should fall within 20%–80% of the machine's maximum shot capacity for optimal process stability and part quality.