HOT RUNNER SYSTEMS IN INJECTION MOLDING

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Plastics are continuing to gain popularity in the market as the injection mold maker keeps an eye on incorporative development and trends to improve the quality of molded parts. 

When it comes to making hot runner mold, it enables the mold maker to create high-quality tools. Further, it increases the efficiency of injection molding machines and the quality of parts. 

It allows access to unlimited features to design a mold for different applications using different materials and processes, decreasing the waste and cost of production.  It has excellent capabilities to produce less handling and high-quality applications for performing better in the manufacturing process of injection molding than the cold runner system. 

What is Hot Runner Systems?

In this method, the nozzle gets extended and has a balance manifold to heat the solid materials and then directly inject into the multi mold cavities to produce the final applications. Hot Runner Systems are a feed system in the injection molding machine to feed the plastic granules heating at a specific temperature. Then, deliver this molten liquid from the nozzle through internal channels (called runners) to fill the multi-cavity in the molds for creating the final products. 

Moreover, it’s a two-plate injection molding assembly where a heated manifold and nozzle keeps the liquified plastic in the molten state. Flow controls by a temperature control system and injects into the cavities to form its shape at coolant temperature. Hot runner is a powerful solution in modern plastic injection molding.

The process in Hot Runner Systems:

This system involves various processes to consider from creating mold to injection molding for high-quality production and assembly. Some process that needs to consider are:

  • Composition: Nozzles, Manifolds, Flow control, Temperature controller, and Connections are the main components of a hot runner system to manufacture different shapes and sizes of applications in industrial spaces.
  • Design: It needs unique features to select the right design of application for the best fit. It is best to use as a result of tip gates(most common), valve gates, edge gates, or sprue gates.   ​
  • Application: It requires the proper design and configuration, so that flow passes through the gates into cavities to meet the specification of an application.

Hot runners are ideal for the production of high-volume, inexpensive parts. The mold and the hot runner system are compatible during the designing and manufacturing process.

Types in Hot Runner Systems:

The selection of gates types is crucial in the technology of hot runners. Gate styles of hot runner systems in injection molding determines the dimensions of applications:

  • Hot Tip Hot Runner Systems:

​This type is the most common in the injection molding method to produce small to medium plastic parts. ​Hot tip involves different nozzles and different nozzle inserts of different shapes and sizes. It’s capable to balance the temperature at gates and combining nozzle inserts with the cooling system. It’s suitable for micro-production to produce crystalline or non-crystalline plastics.

  • Sprue Hot Runner Systems:

This type is suitable for the production of medium to larger parts. It gives strength through the smooth open pipe and molten plastic goes through the gates at a low shear rate. It helps in giving strength to the applications of the product, reducing deformation rate and gate mark.

  • Valve Gating Hot Runner Systems:    

This type is another common technique in injection molding through the valve pin controller. It helps to control the open/close of the gating system at pre-time for smooth finishing.

Why choose Hot Runner Systems?

  • It’s ideal for modern and smooth finish construction of the mold.
  • It injects the molten plastic into the cavity to improve the smooth surface of molded parts and the efficiency of machines.
  • Likewise, it contains temperature-controlled heating devices to maintain the liquified flow of plastics from the nozzle to the gates, filling the cavities in the injection mold. 
  • It has great controlling systems to control the entire process to reduce costs, shorten cycle time, and less material usage. 
  • It has an insulated and heated ability to keep the molten plastic flowing, reduce injection pressure and production interruption.
  • It has the flexibility to use more features to choose design and colours.
  • Likewise, it contains a variety of gate types to choose from on the specification of applications.
  • The optimal sizes of the runners involve shear rates, temperature, pressure drop, time-frequency impacts on the entire performance of the product.

CONCLUSION

Hot Runner systems are suitable for crystalline and non-crystalline plastics and require different nozzles, gate inserts, runner boards and other components. The right selection of molds, materials, and processes for hot runner systems all are prerequisites for a successful production run.

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