Gas assisted injection molding (GAIM) is a manufacturing process that uses pressurized gas to create hollow plastic parts. The process begins with the injection of molten plastic into a mold cavity. As the plastic cools and hardens, a gas is injected into the mold cavity through a small orifice. The gas expands and forces the plastic to expand, creating a hollow cavity in the part.
Here's how the process generally works:
Injection Phase: The polymer resin is melted and injected into the mold cavity under high pressure, just like in conventional injection molding.
Gas Injection Phase: Once a certain portion of the part is filled with molten plastic, gas (usually nitrogen) is injected into the mold. The gas pushes the molten plastic ahead of it, displacing material and forming a hollow section within the part.
Cooling Phase: After the part is completely filled with plastic and gas, the mold is cooled to solidify the plastic.
Gas Removal Phase: Once the part has cooled and solidified, the gas is released from the mold, leaving behind the hollow section.
GAIM offers a number of advantages over traditional injection molding, including:
Reduced material usage: GAIM can reduce material usage by up to 50%, as the gas fills the voids in the part, eliminating the need for additional plastic.
Improved part strength: The gas-filled cavity in a GAIM part provides additional strength and rigidity, making the part more resistant to deformation and stress.
Reduced cycle times: GAIM can reduce cycle times by up to 25%, as the gas helps to cool the part more quickly.
Improved surface finish: The gas-filled cavity in a GAIM part helps to produce a smoother, more uniform surface finish.
GAIM is a versatile process that can be used to produce a wide variety of plastic parts, including bottles, containers, housings, and other complex shapes. It is a good choice for parts that require high strength, low weight, or a smooth surface finish.