Why are cold and hot runners different

　　Cold runner and hot runner are two common runner systems in injection molds,which have significant differences in structure,principle,and application.The following will provide a detailed explanation of the differences between the cold runner and the hot runner.

　　1.Structural differences:

　　-Cold runner:Cold runners are usually composed of metal materials,such as steel or aluminum.This runner system forms a solid channel in the mold without additional heating or cooling equipment.The cold runner structure is relatively simple and is generally used for injection molding of plastic products with simple shapes.

　　-Hot runner:The hot runner is composed of specialized heating elements and a hot runner system.Heating elements are usually made of high-temperature resistant alloys,which maintain the temperature inside the flow channel through heating.The structure of the hot runner is complex and needs to be connected to the control system to accurately control temperature and ensure smooth flow of the runner.

　　2.Heating and cooling differences:

　　-Cold runner:There is no heating equipment in the cold runner system,and the plastic will naturally cool after injection.This cooling method can lead to a longer production cycle in some cases where a longer cooling time is required,but due to the lack of heating,it can ensure that the plastic material is not affected by thermal degradation and deformation.

　　-Hot runner:The hot runner heats the runner through heating elements,keeping the plastic at a consistently high temperature.This heating effect enables the plastic to fill the mold cavity more evenly,while also accelerating the cooling rate of the plastic.The hot runner can therefore shorten cooling time,improve production efficiency and product quality.

　　Cold runner and hot runner

　　3.Differences in scope and complexity of application:

　　-Cold runner:Cold runner is suitable for injection molding of simple shaped plastic products,such as flower pots,product packaging,etc.The runner system is relatively simple,with low manufacturing and maintenance costs,and is suitable for situations where production efficiency is not required.

　　-Hot runner:Hot runner is usually used for injection molding of complex shaped plastic products,such as automotive parts,electronic product casings,etc.The hot runner can achieve control of multiple injection points,allowing complex structured products to be injection molded in one go,reducing subsequent processing and assembly processes.However,the hot runner has a complex structure and high manufacturing and maintenance costs,making it suitable for situations with high requirements for product quality and production efficiency.

　　4.Production efficiency and cost factors:

　　-Cold runner:Due to the relatively long cooling time and production cycle of the cold runner,the production efficiency is relatively low.However,the manufacturing and maintenance costs of cold runners are relatively low,making them suitable for situations where production efficiency is not high.

　　-Hot runner:Due to the advantages of heating and cooling,the hot runner can shrink