The GAIN process
can create large or intricate
parts with no "molded-in" stress or sink marks.

1. The process begins when a "short shot" of thermoplastic is injected into a mold, partially filling it with a predetermined amount of resin.

2. A resin/gas shut off valve is used to isolate the resin in the mold from the barrel.

3. Using either a nozzle or gas pins, nitrogen is injected into the center of the hot resin. Following the path of least resistance it forms hollow channels and directs the resin to the last area of the mold to fill.

4. As the gas expands in the cavity, forcing the plastic in front of it, all of the surfaces receive an equal pressure creating an even "pack out" of the part. This brings the following benefits: shortened cooling cycle, elimination of sink marks and improved dimensional stability.

5. The nitrogen gas is vented either through a sprue break, if gas was injected through the nozzle, or back through the self-venting pins if injected by pins.