Cold runner and hot runner are two common runner systems in plastic injection molds,which have their own advantages and applicability in different applications.The following will provide a detailed explanation of the application scenarios of cold and hot runners.

　　Application scenarios for cold runner:

1. Large injection molding:For large injection molding parts,a cold runner system is usually more suitable.Large injection molded parts have a large volume and weight,and liquid plastic is more susceptible to heat shrinkage.If a hot runner system is used,the plastic will solidify prematurely,leading to incomplete filling.The cold runner system can reduce the thermal shrinkage of plastic,which helps to achieve complete filling and cooling.

   
   

　　2.Injection molding of high-temperature sensitive materials:Some high-temperature sensitive plastic materials are prone to decomposition or oxidation during the injection molding process,leading to a decrease in product quality.A cold runner system can reduce the conduction of heat energy,reduce the exposure time and contact temperature of plastics,and thus reduce the decomposition and oxidation of high-temperature sensitive materials.

　　3.High value plastic injection molding:Some high value plastic materials have high loss costs during the injection molding process.The cold runner system can reduce material loss and save production costs because it does not require the use of hot runner joints and hot runner throats.

　　Application scenarios of hot runner:

　　1.Small or quasi dense injection molding:For small or high-precision injection molded parts,a hot runner system is a better choice.The hot runner system can provide a more uniform temperature distribution,reduce condensation and channel formation,thereby achieving more accurate filling and accurate size control.

　　2.Complex injection molding structure:For injection molded parts with complex structures or multiple discharge ports,the hot runner system can flexibly control the flow path and filling method of plastic materials,making the injection molding process more controllable and stable,and producing higher quality products.

　　3.High production capacity requirements:The hot runner system has faster heating speed and higher temperature control ability compared to the cold runner system,which enables the hot runner system to meet the production needs of high production capacity injection molding,improve production efficiency,and reduce injection molding cycles.

　　It should be noted that not all injection molded parts are suitable for using cold or hot runner systems.Choosing a cold runner or a hot runner requires comprehensive consideration of factors such as product size,shape,material characteristics,production requirements,and selection based on actual situations.In some cases,a combination of cold and hot flow channels can also be considered to fully leverage their respective advantages.