Gas-assisted injection molding (GAIM) uses pressurized nitrogen gas injected into the melt stream to create hollow sections, reduce material usage, and eliminate sink marks in thick-walled parts.
The mold cavity is partially filled with plastic (typically 60-80% full). Nitrogen gas is injected through gas pins into the melt stream. The gas pushes the molten plastic ahead, filling the cavity completely. Gas pressure is maintained during cooling to compensate for shrinkage. The gas is vented before mold opening. The result is a part with solid skin and hollow internal channels.
Eliminates sink marks on opposite-side cosmetic surfaces. Reduces part weight by 10-40% with hollow sections. Shortens cycle time by reducing cooling time for thick sections. Improves dimensional stability with lower molded-in stress. Enables larger parts with lower clamp tonnage requirements. Reduces material cost significantly.
Handles and grips (tools, kitchen appliances, sporting goods). Automotive door handles and interior trim components. Furniture components (chair arms, table legs). Appliance panels with thick bosses and ribs. Structural foam alternative for load-bearing parts.