Variable-temperature injection mould circulating system

Abstract

The invention relates to a variable-temperature injection mould circulating system which comprises a hot oil system, a cold oil system and an oil return delay system, high-temperature high-thermal conductivity oil is used as a heat transfer medium, and the heating and the cooling of heat using equipment are balanced through a hot oil pump and a cold oil pump with the same flow speed. The oil pumps continuously work, and the flowing process of the oil is changed through a pressure-regulating valve. When a mould is heated, the hot oil is introduced and returns to a hot oil tank; when the mould is cooled, the cold oil is introduced and returns to a cold oil tank to ensure that the hot oil and the cold oil can not be mutually mixed. An oil return delay switching technology is adopted to finish the complete disconnection of cold and hot oil systems, and the energy utilization ratio is improved.

Description

technical field [0001] The invention relates to a circulation system for controlling the temperature of a plastic mold, to be exact, a circulation system capable of changing the temperature of the plastic mold according to requirements according to different time periods of injection molding. Background technique [0002] Plastic injection molding products play a very important role in various industries of the national economy such as agriculture, national defense construction, transportation, instrumentation, etc., but according to the traditional injection molding process, there are inherent deficiencies, and the formed products inevitably exist. Many defects, such as poor product precision, lack of material (cavity not filled), shrinkage, surface depression, obvious weld marks, large internal stress of the product, and serious problems such as cracking during demoulding or use. Most of the above-mentioned defects are caused by the injection molding process itself. For ex...

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Problems solved by technology

[0002] Plastic injection molding products play a very important role in various industries of the national economy such as agriculture, national defense construction, transportation, instrumentation, etc., but according to the traditional injection molding process, there are inherent deficiencies, and the formed products inevitably exist. Many defects, the common ones are poor product precision, lack of material (cavity is not full), shrinkage, surface depression, obvious weld lines, large internal stress of the product, and serious problems such as cracking during demoulding or use.

Most of the above-mentioned defects are caused by the injection molding process itself. For example, most polymer melts have high viscosity, and the mold is forcibly filled in the low-temperature mold cavity, and the internal stress cannot be eliminated due to rapid cooling under high shear stress.

The current conventional practice is to use a mold temperature controller to raise the mold to a certain temperature during the injection molding of the mold, which can improve the flow properties of the plastic melt and reduce the internal stress of the product, but because of the factors of the injection molding cycle, Therefore, the temperature of the mold cannot be raised too high, which restricts the further improvement of the melt fluidity and the reduction of the internal stress of the product.

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