The temperature of the injection mold has a great influence. Especially on the filling flow of the plastic melt, solidification and setting, production efficiency,the shape and dimensional accuracy of the plastic parts.
Each plastic injection molding has a reasonable mold temperature area, so that the melt fluidity is easy to fill the cavity, the plastic parts shrink and warp, the size is stable, the mechanical properties and surface quality are also high.
In order to control the temperature of the mold, we need “design” a temperature adjustment system. Generally, the mold cooling or heating method is used. If necessary, both are used. There are many cooling devices used in the mobile phone shell mold.
1. The necessity of temperature adjustment of injection mold
The mold temperature has a great influence on the molding quality and molding efficiency of the rubber parts. In the mold with higher temperature, the fluidity of the molten rubber is better, which is helpful for the rubber to fill the cavity and obtain the appearance surface of the high-quality rubber parts, but the curing time of the rubber will be longer and it will be easily deformed when it is ejected;
For crystalline compounds, it is more conducive to the crystallization process to avoid changes in the size of the rubber parts during storage and use; in molds with lower temperatures, it is difficult for the molten compound to fill the cavity, resulting in increased internal stress and a matt surface , Defects such as silver streaks and weld marks are produced.
Different rubber materials have different processing techniques, and the surface requirements and structures of various rubber parts are different. In order to produce rubber parts that meet the quality requirements in the most effective time. This requires the mold to maintain a certain temperature and temperature.The more stable, the more consistent the requirements of the produced plastic parts in terms of size, shape and appearance quality.
Therefore, in addition to the factors of injecton mold manufacturing, mold temperature is an important factor to control the quality of plastic parts. Mold design should fully consider the mold temperature control method.
2. The principle of injection mold temperature control
In order to ensure the production of plastic parts with high appearance quality requirements, stable dimensions, and small deformation in the most effective time, the basic principles of mold temperature control should be clearly understood during design.
① Different rubber materials require different mold temperatures.
② Molds with different surface qualities and different structures require different mold temperatures. Which requires pertinence when designing the temperature control system.
③ The temperature of the front mold is higher than that of the rear mold.
Generally, the temperature difference is about 2 ~ 3º.
④ The temperature of the front injection mold with fire pattern is higher than the temperature of the general mold.
When the front mold needs hot water or hot oil, the general temperature difference is about 40º.
⑤ When the actual mold temperature cannot reach the required mold temperature, the mold should be heated up. Therefore, when designing the mold,we should consider whether the heat of the rubber brought into the mold. So that it can meet the mold temperature requirements.
⑥ The heat brought into the mold by the rubber material. The means of heat radiation and heat conduction consum. And most of the heat needs to be taken out of the mold by the circulating heat transfer medium.
⑦ It should balance the injection mold temperature without local overheating or coldness.