Principle of gas-assisted injection molding
The principle of gas-assisted injection molding is relatively simple. In the process of injection filling, the gas with lower pressure than the injection pressure is injected into the melt, usually several to dozens of megapascals, and the pressure of the gas is used to realize pressure maintaining and feeding. The principle of gas-assisted injection molding. The principle of gas-assisted injection molding is that the gas enters from the inside of the plastic melt. When molding, the accurately measured melt is injected into the mold cavity first, and then the gas is injected into the melt through a special nozzle. The gas diffusion pushes the melt to fill the mold cavity. After mold filling, the pressure of the gas in the melt remains unchanged or rises to maintain pressure and replenish the material. After cooling, the gas in the plastic part can be removed. The pressure forming method of gas on the surface of plastic melt is also called surface gas forming method. This method is a method of injecting high-pressure gas into the special closed part of the bottom surface of the plastic injection molding products in the mold to make the surface of the injection molding products free of shrinkage marks.
Gas-assisted injection molding has the characteristics of injection molding. This special closed area can also be called the pressurized area, and each pressurized area is surrounded by the seal connecting the finished product to prevent gas leakage. The section of the seal can be rectangular or triangular, which can strengthen the rigidity of the finished product. Of course, the surface gas molding method adopted by Dongguan Machiko Injection Molding Plant will leave obvious traces in the pressurized area, but it will never affect the surface of injection molding products. The surface gas forming method is particularly suitable for the following situations:; When the shrinkage of plastics is very high; When the back of the cylindrical object in the finished product is easy to be dented; The process of melt filling mold cavity is very long; When the finished product is thin-walled and irregular and cannot be aerated or thick-walled. In gas-assisted injection molding, the quantity of melt is very important. If too much melt is injected, the wall thickness will be uneven; On the contrary, if too little melt is injected, the gas will break through the melt and make the molding impossible.