Green Vitality Industry Co., Ltd.
Green Vitality Industry Co., Ltd.

What is injection molds? Can it help my enterprise? Many people may not understand what injection molds are when they first hear this name. This article hopes to help you better understand injection molds and their application fields and characteristics. Below, we will take you to understand the application fields and functional characteristics of injection molds.

The temperature control method of injection molds

The temperature at various points inside the injection molds is uneven and related to the time point in the injection cycle. The function of the mold temperature controller is to keep the temperature constant between 2min and 2max, that is to prevent temperature differences from fluctuating during production or intervals. There are several control methods suitable for controlling the temperature of the mold, including controlling the fluid temperature, which is commonly used, and the control accuracy can meet most requirements. When using this control method, the temperature displayed on the controller is not the same as the mold temperature; the temperature of the mold fluctuates significantly because the factors affecting the mold's heat are not directly measured and compensated. These factors include changes in injection cycle, injection speed, melting temperature, and room temperature.

Secondly, direct temperature control of injection molds. This method installs temperature sensors inside the mold, which is only used when the mold temperature control accuracy is relatively high. The main features of mold temperature control include: the temperature set by the controller is consistent with the mold temperature; the factors affecting the mold's heat can be directly measured and compensated. In general, the stability of mold temperature is better than controlling fluid temperature. In addition, the reproducibility of mold temperature control in the production control process is better. Thirdly, it is joint control. Joint control is a comprehensive method of the above two methods, which can control both the temperature of the fluid and the mold at the same time. In joint control, the position of the temperature sensor in the mold is extremely important. When placing the temperature sensor, the shape, structure, and position of the cooling channel must be considered. In addition, the temperature sensor should be placed in the place where the injection quality plays a decisive role. There are many ways to connect one or more mold temperature controllers to the injection molding machine controller. It is best to use a digital interface for ease of operation, reliability, and anti-interference.

The heat balance control of injection molds is critical to producing injection-molded parts

Inside the mold, the heat brought by the plastic (such as thermoplastic) is transferred to the material and mold steel by thermal radiation and transferred to the conductive fluid through convection. In addition, heat is transferred to the atmosphere and the mold frame through thermal radiation. The heat absorbed by the conductive fluid is taken away by the mold temperature machine.

The purpose of controlling the mold temperature and the influence of mold temperature on the injection-molded parts in the injection molding process, the main purpose of controlling the mold temperature is to heat the mold to the working temperature and maintain the mold temperature constant at the working temperature. If the above two points are successful, the cycle time can be optimized, thereby ensuring stable and high-quality injection-molded parts. Mold temperature will affect surface quality, fluidity, shrinkage rate, injection cycle, and deformation.

Too high or too low mold temperature will have different effects on different materials. For thermoplastics, slightly higher mold temperature usually improves surface quality and fluidity but extends cooling time and injection cycle. Slightly lower mold temperature will reduce shrinkage inside the mold but increase the shrinkage rate of the injection-molded parts after demolding. For thermosetting plastics, slightly higher mold temperature usually reduces cycle time, and the time is determined by the time required for the part to cool. In addition, a slightly higher mold temperature will also reduce plasticizing time and reduce cycle times in plastic processing.

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