Plastic Chair With Back Mould

What are gas-assisted injection moulds?

The principle of gas-assisted injection is to create a hollow section in the interior of the injection molded part by high-pressure gas. The volumetric pressure of the gas is used to reduce the residual internal stress of the product, eliminate the surface shrinkage of the product, and reduce the material used, which shows the superiority of the conventional injection molding. It can form thick and thin-walled composite plastic parts which are difficult to process by traditional injection molding, reduce the number of parts in the assembly structure, thereby reducing the mold, assembly line, and labor demand, and the injection pressure required to save production cost is small. On the one hand, a small type injection machine can be utilized. 

In the gas assist molding process, the plastic material is melted and injected into the mold cavities via the conventional plastic injection molding process. Plastic material in contact with the mold walls begins to solidify first. As this happens, nitrogen gas is injected into the mold through strategically designed and placed gas channels, providing the pressure that pushes the plastic material into the mold extremities.

Once the plastic cures, the nitrogen is vented and the gas-assist injection molded plastic parts are removed from the mold. Gas assist injection molding process animation.

Gas assistant molds, is a kind of high technology for plastic injection molding, is widely used in auto parts, home appliance parts, furniture parts whose parts are heave and thicker, we used gas-assisted molding technology to make the part hallow and make it light. This kind of mold needs a more complicated mold structure and an additional gas assistant device.

Advantages of using the gas-assisted system in moulds

1. Less plastic material needed (material savings)

2. Reduced part weight (in some cases up to 40%)

3. Decreased cycle time

4. Increased part strength and rigidity

5. Reduced warpage and distortion

6. Improved part appearance (eliminates sink marks and surface blemishes)

7. Reinforces ribbed parts

8. Increased design options for complex parts, reducing multiple part assemblies, and metal to plastic conversions

9. Enables use of smaller plastic injection molding presses

Here viewing our plastic chair mould testing