Injection molding machine structure: Injection system

author: Universe plastic

2024-05-08

The injection system is an important part of the injection molding machine, which can transform the plastic material from a solid state to a molten state, and then inject it into the mold for cooling and forming.

The performance of the injection system directly affects the quality and production efficiency of injection molded products. Universe Plastic Engineers will take you to understand the injection system:

The structural components of the injection system

1. Hopper

Responsible for storing plastic granules or powder and feeding them evenly into the barrel. It is usually equipped with a drying device to prevent the material from getting damp and affecting the molding quality.

2. Barrel

Responsible for heating plastic materials to melt them, making the inner wall of the barrel smooth and wear-resistant. The screw is installed in the barrel, and the outside is equipped with a heater and cooling system.

Injection molding machine injection system

3. Screw

Responsible for heating, melting and transporting plastic particles to the injection position. A screw has three functional sections: feeding section, compression section, and metering section. It is also divided into general-purpose screw and special plastic screw types.

4. Nozzle

It connects the barrel to the mold and injects molten plastic into the mold. It is divided into straight-through nozzle and closed nozzle types.

5. Heating system

Responsible for providing heat to the barrel and screw to melt the plastic, usually an electric heating ring or heater, distributed outside the barrel.

6. Cooling system

It is mainly responsible for controlling the temperature of the barrel and nozzle to prevent overheating inside the barrel, which may cause thermal decomposition and blackening of the plastic. There are two types: air cooling and water cooling.

7. Injection cylinder

It is responsible for driving the screw to rotate and move forward, pushing the molten plastic forward and into the mold. There are 2 types: hydraulic cylinder or electric drive.

8. Retreat cylinder

Responsible for driving the screw back to prepare for the next injection cycle. There are 2 types: hydraulic cylinder or electric drive.

How the injection system works

1. Feeding: Add plastic particles from the hopper into the barrel feeding section.

2. Heating: The rotating screw transports the plastic particles to the compression section, and the barrel is heated to melt and compress the plastic particles.

3. Homogenization: In the metering section, the plastic melt is further evenly melted to reach a uniform molten state.

4. Injection: The injection cylinder pushes the screw forward and injects the molten plastic into the mold cavity through the nozzle.

5. Pressure holding: After injection, the screw maintains a certain rotation pressure to continue filling and solidifying the mold cavity, reducing plastic shrinkage and bubble generation.

6. Retreat: After the plastic in the mold cools and solidifies, the screw retreats under the action of the retreat cylinder to prepare for the next injection.

Injection parameter names and functions

1. Injection pressure: affects the filling effect of plastic and the density of the product.

2. Injection speed: affects the fluidity of plastic and the filling time of the mold.

3. Injection volume: The amount of plastic injected each time affects the weight and size of the product.

4. Holding time: affects the density and shrinkage rate of the product, which is determined according to the product thickness and material type.

5. Plasticizing capacity: The ability of the screw to melt plastic per unit time affects production efficiency.

Routine maintenance of injection system

1. Regular cleaning: Clean the hopper, screw, barrel and nozzle to prevent material residue and impurities from affecting quality.

2. Lubrication and maintenance: Regularly lubricate the moving parts of the injection system to reduce friction and wear.

3. Temperature control: Strictly control the temperature of the heating and cooling system to prevent material degradation and screw overheating.

4. Check wear: Regularly check the wear of the screw, barrel and nozzle, and replace damaged parts in time.

5. Troubleshooting: Deal with failures in the injection system in a timely manner, such as blockage, leakage, temperature abnormalities, etc.

Summarize

The injection system is the core part of the injection molding machine. Its performance and usage directly affect the quality of injection molding and production efficiency. In injection molding projects, it is not only necessary to select a suitable injection molding machine, but also to set accurate injection system parameters to complete high-quality injection molding manufacturing.

Dongguan Universe Plastic Co., Ltd. has more than 15 years of injection molding experience. It is recommended that routine maintenance and maintenance of injection molding machine parts is the key to ensuring the smooth progress of injection molding production and product quality.

If you are looking for an excellent injection molding service provider, please contact us to get the latest injection molding quotation.

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