The key advantages and benefits of the gas assist process are as follows:
Gas assist injection molding is a variation of conventional injection molding that can be easily retrofitted to an existing injection press by the addition of an auxiliary gas unit. The usual injection of molten plastic is assisted by the introduction of pressurized gas (usually nitrogen) into the mold. The gas produces a bubble which pushes the plastic into the extremities of the mold creating hollow sections as the bubble propagates.

Gas assist molding offers a variety of process and design features which can help to meet application requirements. Some of the potential features and benefits are listed below:
Extend Design Guidelines

Hollow Thick Parts or Thick Sections Within Parts Can Enable:
– Large ribs or flow leaders without process penalties
– Higher stiffness-to-weight ratio in structured parts
– Molding large cross-sections (parts consolidation)
Lower Production Costs

Short Shot Process With Hollow Sections Can Result in:
– Lower clamp tonnage
– Lower injection pressures
– Reduced cycle time vs. solid sections
Smooth Surface Appearance Can Result in:
– Improved aesthetics vs. structural foam
– Reduced secondary operations
Dimensional Stability
Increased design flexibility – combines strength of structural foam with cosmetics of injection molding, allowing multiple features designed right into your parts.

High potential to reduce costs – from lower tooling costs to part weight reduction, from lower production cycle times to reduced finishing expenses makes gas assist an attractive option.

Quicker to market – using aluminum molds for shorter mold making leadtimes, as well as reducing in-plant post-molding processing.

This information on gas-assist was taken from G.E.'s website at
GE Plastics