Influence of Injection Mold Temperature on Plastic Parts

There are many factors to influence the injection mold cooling, such as the shape of plastic parts, and the parting surface design, the types, temperature and flow rate of cooling medium, geometry parameters and spatial arrangement of cooling pipe, mold material, melt temperature, eject and mold temperature that plastic parts requiring, thermal cycling interaction between plastic parts and molds,etc.

Below is the influence of injection mold temperature on plastic parts:

Low mold temperature can reduce molding shrinkage rate of mold.

Uniform mold temperature,short cooling time and fast speed injection can reduce the warping deformation of the plastic parts.

For crystalline polymers, increasing the mold temperature can stabilize the size of the plastic parts to avoid the post-crystallization phenomenon, but it will lead to the defects of the elongation of the molding cycle and the brittleness of plastic parts.

With the improvement of the crystallinity of crystalline polymer, plastic stress cracking resistance is reduced, so reducing the mold temperature is favorable. But for the amorphous polymers of high viscosity,due to its endurance cracking is directly related to the internal stress of plastic parts, thus improving the mold temperature and mold filling speed, and reducing the feeding time is favorable.

Increasing the mold temperature will improve the surface quality of plastic parts. In the process of determining the mold temperature, the mold temperature directly influences the mold filling, shaping of plastic parts, molding cycle and the quality of molded parts. Mold temperature depends on plastic crystallization, size and structure of plastic parts,performance requirements and other technological conditions such as the melting temperature, injection speed and pressure and plastic molding cycle, etc. For the amorphous polymer, the melt is solidified with the decrease of temperature after injection mold cavity, but it does not occur phase change. The mold temperature mainly affects the viscosity of the melt, that is, the filling rate. Therefore,for the low melt viscosity and medium amorphous plastics such as polystyrene cellulose acetate etc,the lower mold temperature can shorten the cooling time.

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