Gas auxiliary injection moulding apparatus and its control method

Abstract

This invention provides an injection molding device assisted by gas and its control method for controlling the N2 pressure injected into plastic products including three parts of generation, pressure increasing and pressure control of N2, in which, the high pressure gas route in the control part is controlled by the low pressure gas route, an electronic control system is responsible for the adjustment of gas pressure in the low pressure gas route to realize accurate control of N2 pressure. This invention also provides a whole set of gas assisting molding device for controlling the generation, boosting and pressure of N2 accurately to control the injection pressure and pressure-keeping in many stages accurately and realize gas-assisting molding of plastic products.

Description

technical field [0001] This invention relates to injection molding and, in particular, to gas-assisted injection molding for the manufacture of plastic articles having hollow regions inside. More specifically, it relates to a gas-assisted injection molding system and its control method for controlling the switch of the gas passage and the adjustment of the gas pressure. Background technique [0002] Injection molding is one of the most commonly used processing methods for manufacturing plastic products. The plastic in the molten state is first injected into the mold cavity, and after cooling and solidifying, a plastic product with a certain shape is obtained, and then the mold cavity is opened to take out the plastic product. [0003] With the continuous improvement of technical requirements for plastic products, traditional injection molding has many limitations for the production of various large-scale, complex-shaped plastic products with strict surface quality requireme...

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Problems solved by technology

[0006] The pneumatic on-off valve 28 can realize fast switching, ensuring that the nitrogen injection pressure quickly reaches the preset pressure value, so as to break through the solidified layer on the surface of the product melt and enter the inside of the melt; the pressure regulating valve 24 and the pressure sensor 27 are composed of an electronic control system 50 The nitrogen pressure closed-loop control loop solves the problem of precise control of the nitrogen injection pressure; the pneumatic switch valve 33, the electric throttle valve 34, the one-way valve 36, the cylinder 38, and the pressure stabilizing valve 39 are used to realize the nitrogen pressure in the pressure maintaining process. Adjustment speed of stage gas pressure and nitrogen discharge and recovery; electric throttle valve 34 is used to control the speed of nitrogen pressure drop; pneumatic switch valve 35 is used to discharge nitrogen below a certain pressure into the atmosphere

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