Understand the hot runner system in one article

Hot runner system, also known as hot runner system, mainly consists of hot runner sleeve, hot runner plate, and temperature control electrical box. Our common hot runner systems have two forms: single-point hot gate and multi-point hot gate. Single-point hot gate uses a single hot sprue sleeve to directly inject molten plastic into the mold cavity. It is suitable for plastic molds with a single cavity and a single gate; multi-point hot gate branches the molten material to various locations through a hot runner plate. The heat is divided into the sprue sleeve and then enters the mold cavity. It is suitable for single-cavity multi-point feeding or multi-cavity molds.

◆Advantages of hot runner system

(1) There is no nozzle material and no post-processing is required, making the entire molding process completely automated, saving working time and improving work efficiency.

(2) Small pressure loss. The temperature of the hot runner is equal to the temperature of the nozzle of the injection molding machine, which avoids surface condensation of raw materials in the runner and reduces injection pressure loss.

(3) Repeated use of nozzle materials will degrade the performance of plastics, but using a hot runner system without nozzle materials can reduce the loss of raw materials, thereby reducing product costs. The temperature and pressure in the cavity are uniform, the plastic parts have small stress and uniform density. Under smaller injection pressure and shorter molding time, better products can be injection molded than ordinary injection molding systems. It can show its advantages even more for transparent parts, thin parts, large plastic parts or high-demand plastic parts, and it can produce larger products with smaller models.

(4) The thermal nozzle adopts standardized and serialized design, equipped with various optional nozzle heads, and has good interchangeability. The uniquely designed and processed electric heating ring can achieve uniform heating temperature and long service life. The hot runner system is equipped with hot runner plates, temperature controllers, etc., with exquisite design, various types, easy use, and stable and reliable quality.

◆Disadvantages of hot runner system application

(1) The closing height of the overall mold is increased. Due to the installation of hot runner plates, etc., the overall height of the mold is increased.

(2) Thermal radiation is difficult to control. The biggest problem with hot runner is the heat loss of the runner, which is a major issue that needs to be solved.

(3) There is thermal expansion, and thermal expansion and contraction are issues we need to consider when designing.

(4) The cost of mold manufacturing increases, and the price of standard parts of the hot runner system is higher, which affects the popularity of hot runner molds.