Principles of Temperature Control for Injection Mold
The temperature of the injection mold has a great influence on the filling flow, curing setting, production efficiency, and shape and dimensional accuracy of the plastic melt.After solving the problem, the injection molding machine can also better produce the product
Each plastic injection molding has a reasonable mold temperature region, which makes the melt fluid and easy to fill the cavity. After the mold is demoulded, the shrinkage and warpage are small, the size is stable, and the mechanical properties and surface quality are also high. In order to control the temperature of the mold, a temperature adjustment system must be designed. Generally, the method of cooling or heating the mold is used, and if necessary, both are used. There are many cooling devices used in the mold of the mobile phone shell.
1.Necessity of temperature regulation
The mold temperature has a great influence on the molding quality and molding efficiency of the rubber part. In the mold with higher temperature, the fluidity of the molten rubber is better, which is conducive to filling the cavity of the rubber and obtaining a high-quality appearance of the rubber part, but it will make the rubber curing time longer and easily deform when ejected. For crystalline rubber, it is more conducive to the crystallization process, avoiding changes in the size of the rubber parts during storage and use; in the mold with a lower temperature, it is difficult for the molten rubber to fill the cavity, resulting in increased internal stress and a matte surface , Resulting in silver streaks, welding marks and other defects.
Different rubber materials have different processing techniques, and the surface requirements and structures of various rubber parts are different. In order to produce plastic parts that meet the quality requirements in the most effective time, this requires the mold to maintain a certain temperature and mold temperature. The more stable, the more consistent the requirements on the size, shape, appearance and quality of the plastic parts produced. Therefore, in addition to the factors of mold manufacturing, mold temperature is an important factor for controlling the quality of plastic parts. The mold temperature control method should be fully considered when designing the mold.
2. Principles of mold temperature control
In order to ensure the production of high-quality appearance, stable size, and small deformation plastic parts in the most effective time, the basic principles of mold temperature control should be clearly understood when designing.
① Different rubber materials require different mold temperatures.
② Different molds with different surface quality and different structures require different mold temperatures, which requires pertinence when designing a temperature control system.
③ The temperature of the front mold is higher than the temperature of the rear mold. Generally, the temperature difference is about 2 ~ 3º.
④ The temperature of the front mold required by the fire pattern is higher than the temperature of the front mold required by the normal smooth surface. When the current mold is required to pass 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, full consideration should be given to whether the heat brought by the rubber into the mold can meet the mold temperature requirements.
⑥ Except for the heat that is brought into the mold from the rubber material through heat radiation and heat conduction, most of the heat needs to be taken out of the mold by the circulating heat transfer medium.
⑦ The mold temperature should be balanced without local overheating or overcooling.