PROCESS

Identical to injection molding except that initial shot of plastic does not fill mold. High pressure nitrogen is shot into mold immediately after plastic, which hollows out certain thick areas of part. This helps reduce weight in thicker parts.

RAW MATERIALS

Most raw materials can be used.

TOOLING

Machined steel. Must be specially designed with mold flow analysis to enhance the hollowing-out of thick areas.

COST

Tooling costs are generally high. Part prices generally higher than with injection molding.

ADVANTAGES

Saves raw material because of hollow areas. Enhances structural integrity.

DISADVANTAGES

Special care must be taken in designing parts. High cost of tooling and mold flow analysis.

EXAMPLES

Toys, auto parts & anything with thick areas.