Classification and process of gas-assisted injection molding




According to the characteristics of gas-assisted injection molding, gas-assisted injection molding can be realized by adding a set of gas supply device to the existing injection machine. According to the use abroad, gas-assisted injection molding can be divided into standard molding method, melt reflow molding method and movable core withdrawal method.
(1) Standard forming method
(1) Standard molding method of gas injection from injector nozzle Standard molding method of gas injection from injector nozzle. A part of the melt is injected into the mold cavity by the injection machine material sheet; Injecting gas from the injector nozzle to push the plastic melt to fill the mold cavity; Increase the gas pressure to realize pressure maintaining and material replenishing; The gas is removed after pressure maintaining, and the plastic parts are demoulded.
(2) Standard molding method of gas injection from mold cavity Standard molding method of gas injection from mold cavity. The process is completely similar to the gas injection method from the injection machine nozzle introduced by Dongguan Machiko Injection Molding Plant, but the gas introduction point is different. The characteristic of the standard molding method is to fill the cavity with quantitative plastic melt instead of filling the cavity. The amount of plastic melt required is determined by experiment.

(2) Melt reflow molding
Melt reflow molding method, which is characterized by gas-assisted injection molding, is that the plastic melt fills the cavity at first. The difference from the standard molding method is that when the gas is injected, the excess melt flows back to the barrel of the injection machine.
(3) Moveable core exit method
The melt in the moveable core exit method fills the cavity and maintains the pressure; The injected gas movable core exits from the cavity; Increase the pressure of the gas to realize pressure maintaining and feeding; The exhaust gas demoulds the plastic parts.
3、 Characteristics of gas-assisted injection molding
The characteristics of gas-assisted injection molding and injection molding. The gas-assisted injection molding technology can be used for plastic injection molding of various thermoplastic injection molding products, such as television or audio enclosures, various plastic products on automobiles, showers, kitchen utensils, household appliances, daily necessities and toys. Compared with traditional injection molding methods, gas-assisted injection molding has the following characteristics:
(1) It can form plastic parts with uneven wall thickness and complex three-dimensional hollow plastic parts.
(2) The gas flows from the gate to the flow end to form a continuous airflow channel without pressure loss, which can realize low-pressure injection molding. Thus, plastic parts with low residual stress can be obtained, with small warpage deformation and stable size.
(3) Due to the auxiliary filling effect of air flow, the injection molding performance of plastic parts is improved. Therefore, the use of gas-assisted injection is conducive to forming thin-walled plastic parts, reducing the weight of plastic parts and saving raw materials.
(4) As the molding pressure in the mold cavity is reduced, the loss of the mold is reduced, and the working life of the mold is improved. Also because of the low injection molding pressure, plastic parts with large size can be molded on the injection molding machine with small clamping force.
(5) Shorten the production cycle of plastic parts and save production time.