Key Components of a Hot Runner System
A hot runner system is an advanced heating system used in injection molding that directly injects molten plastic into the mold cavity, replacing traditional sprue bushings. Hot runner systems significantly improve product quality, reduce material waste, and shorten production cycles.
The key components of a hot runner system primarily include the following:
1. Hot Runner Manifold
Function: Evenly distributes molten plastic from the injection molding machine nozzle to individual gates.
Material: Typically made of high-temperature alloys such as high-temperature alloy steel or stainless steel.
Structure: Includes feed channels, distribution channels, and gates.
2. Heater
Function: Provides heat to the hot runner manifold and nozzle to maintain the fluidity of the molten plastic.
Types: Includes electric heaters, oil heaters, etc.
Control: Precisely controls the heating temperature through a temperature controller.
3. Temperature Sensor
Function: Monitors the temperature of the hot runner manifold and nozzle and feeds back the data to the temperature controller.
Types: Commonly used thermocouples and thermistors.
Location: Typically installed at critical positions on the hot runner manifold and nozzle.
4. Temperature Controller
Function: Controls the output power of the heater according to the set temperature to maintain a stable temperature of the hot runner system.
Type: PID controllers are commonly used.
Display: Displays set temperature, actual temperature, and other parameters.
5. Nozzle
Function: Delivers molten plastic from the hot runner manifold to the mold cavity.
Types: Different types of nozzles are selected based on product shape and size.
Material: High-temperature, wear-resistant alloy steel.
6. Gate
Function: Controls the speed and flow rate of molten plastic entering the mold cavity.
Types: Needle valve gate, submerged gate, fan gate, etc.
Location: The gate location is selected based on the product shape and molding process.
7. Seal Ring
Function: Prevents leakage of molten plastic and ensures a seal.
Material: High-temperature elastomer.
Advantages of Hot Runner Systems:
Improved product quality: Reduces weld lines and improves surface finish.
Reduced material waste: Reduces sprue and runner waste, improving material utilization.
Shorter cycle time: Reduces cooling time and improves production efficiency.
Suitable for complex products: Can produce products with complex shapes and thin walls.
