Gas-assisted injection molding technology
mainly used in automotive plastic products, home appliances, mobile phone, PDA and laptop computer cases, daily necessities, etc. He can solve some problems in the injection molding process.
The process of gas-assisted injection molding is to inject a precisely measured polymer melt into the cavity, which is the same process as traditional injection molding, until the melt fills the cavity by 60% to 95%. Compressed gas is then injected into the melt, and the front of the melt flow is driven forward by the high-pressure gas in the direction of minimum resistance until it fills the entire cavity. The article is cooled while maintaining the gas pressure. During the cooling process, the gas is pressurized from the inside to the outside to ensure that the outer surface of the product is close to the mold wall, and the secondary shrinkage of the volume caused by the melt cooling and solidification is replenished from the inside by the gas's secondary penetration. After the product is cooled and solidified, the high-pressure gas is discharged, and then the mold is ejected to eject the product to complete a molding cycle.
At present, it is specifically divided into several types: cooling gas-assisted injection molding, vibration gas-assisted injection molding, external gas-assisted injection molding, multi-cavity controlled gas-assisted injection molding, and gas-assisted co-injection molding technologies. Each has its unique advantages. The main advantages of cooling gas-assisted injection molding are: when the cooling gas penetrates the melt, a plug flow effect is generated in the cavity; the residual wall thickness produced by the plug flow is smaller than that of traditional GAIM; the cooling gas also prevents the inside of the part Foaming and producing a smoother inner surface. There are two points for vibration gas-assisted injection molding. One is the introduction of vibration gas, which can improve the melt filling process mechanism and effectively eliminate shrinkage marks and other defects caused by poor fluidity; the second is the introduction of vibration gas in the melt to promote The melt fills the entire cavity. Vibrating gas can reduce the viscoelasticity of the melt and make it easier to flow and orientate during filling. The outstanding advantage of external gas-assisted injection molding is that it can pressurize the points, prevent dents, reduce stress and deformation, and make the product apparent More perfect.
Other advantages are not listed one by one. In short, with the expansion of the application field, more new methods of gas-assisted injection molding have emerged at the historic moment, which has further promoted the development of injection mold processing technology.