Gas-assisted injection molding is a specialized injection molding process that involves injecting pressurized gas into the molten plastic in the mold cavity to create hollow interior channels or cavities within the part. The typical process consists of these key steps:

1. Plastic resin is injected into the mold cavity under high pressure to partially fill the cavity (about filling 80%).
2. Once the plastic has partially solidified, an inert gas like nitrogen is injected through the sprue or a dedicated gas injection channel.
3. The gas follows the path of least resistance and creates hollow sections within the part, conforming to interior contours.
4. The expanding gas packs the plastic against the interior mold surfaces, eliminating sink marks and controlling part dimensions.
5. The part is allowed to completely cool and solidify before the mold opens and the part is ejected.
6. The residual gas is vented out automatically or in a separate degassing process.

The hollow sections formed by the gas reduce the weight of the part and lower material costs. The gas pressure also minimizes part warpage and shrinkage. This allows the production of large,hollow plastic components with premium surface finish and dimensional accuracy.