Problems Needing Attention in the Design of Gas Assisted Injection Moulding Products

Ⅰ. Gas-assisted injection moulding product design

Gas-assisted injection molding technology is an emerging plastic injection molding technology. Its principle is to use high-pressure gas to produce a hollow section inside the plastic injection molding parts, and use gas pressure to replace plastic injection pressure to eliminate product sink marks and complete the injection molding process. The process of gas-assisted injection molding mainly includes three stages: plastic melt injection, gas injection, and gas pressure holding.

According to the different injection volume of the melt, it is divided into short shot and full shot. In the short shot, the gas first pushes the melt to fill the cavity and then maintains the pressure; in the full shot, the gas only maintains the pressure effect.

Ⅱ. The main advantages of gas-assisted injection moulding product design

Solving the problem of sink marks on the surface of the part can greatly improve the surface quality of the part.

The thickening of the local air duct can increase the strength and dimensional stability of the part, and reduce the internal stress of the product and reduce the warping deformation.

Save raw materials, up to 40% to 50%.

Simplify product and mold design and reduce the difficulty of mold processing.

Reduce mold cavity pressure, reduce clamping force, and extend mold life.

The cooling is accelerated and the production cycle is shortened.

Compared with ordinary injection molding process, gas-assisted injection molding technology has incomparable advantages. It is known as a revolution in injection molding process and is widely used in almost all plastic parts such as household appliances, automobiles, furniture, and daily necessities. In the field of home appliances, TV housings, especially large-screen color TV front housings, are one of the earliest and most widely used products using gas-assisted injection molding technology.

Ⅲ. The basic principles of gas-assisted products and mold design

1. When designing, first consider which wall thicknesses need to be hollowed out and which surface sink marks need to be eliminated, and then consider how to connect these parts to become airways.

2. Large structural parts: comprehensively thinned, and partly thickened to be an airway.

3. The airway should be evenly distributed to the entire cavity according to the main material flow direction, and closed-circuit air passages should be avoided.