Injection mold temperature on the plastic melt filling flow, curing stereotypes, production efficiency and shape and dimensional accuracy of plastic parts have a tremendous impact.
Each plastic injection molding has a reasonable mold temperature region, so that the flow of the melt easily filled the cavity easily, plastic parts after shrinkage and warpage small deformation, dimensional stability, mechanical properties and surface quality is high. Control the temperature of the mold must be designed temperature control system, the general method of cooling or heating the mold, if necessary, both the two, the mobile phone shell mold cooling device used more.
1. The need for temperature regulation
Molding temperature of the plastic mold forming quality, molding efficiency has a greater impact in the mold temperature, molten plastic material is better mobility, plastic filling cavity conducive to obtain high-quality plastic surface appearance , But will make the rubber curing time longer, easy to deform when ejecting;
For crystalline compounds, it is more conducive to the crystallization process, to avoid storage and use of plastic parts size change; in the mold temperature, the molten rubber is difficult to fill the cavity, resulting in increased internal stress, the surface matte , Resulting in silver lines, weld marks and other defects.
Different materials have different processing technology, and a variety of plastic parts of the surface requirements and structure of different, in order to produce the most effective time in line with the quality requirements of plastic parts, which requires the mold to maintain a certain temperature, mold temperature The more stable, to produce the plastic parts in the shape and size, appearance and quality of plastic parts, the more consistent the requirements.
Therefore, in addition to mold manufacturing factors, mold temperature is an important factor in controlling the quality of plastic parts, mold design should take full account of mold temperature control.
2 mold temperature control principles
In order to ensure that the most effective time to produce high quality appearance requirements, dimensional stability, small deformation of the plastic parts, the design should be a clear understanding of the basic principles of mold temperature control.
① different plastic materials require different mold temperature.
② different surface quality, different structure of the mold requires a different mold temperature, which requires the design of temperature control system is targeted.
③ front mold temperature is higher than the mold temperature, under normal circumstances, the temperature difference of about 2 ~ 3 º.
④ spark pattern requirements of the front mold temperature than the average front requirements of the mold temperature is high, the current model must be hot or hot oil, the general temperature difference of about 40 º.
⑤ When the actual mold temperature can not meet the requirements of mold temperature, the mold should be heated, so mold design, should take full account of the plastic into the mold of the heat can meet the mold temperature requirements.
⑥ by the rubber into the mold in addition to the heat through the thermal radiation, heat conduction, consumption, the vast majority of heat required by the cycle of heat transfer medium out of the mold.
⑦ mold temperature should be balanced, can not have local overheating, too cold.