Nitrogen Generators for Gas-Assisted Injection Moulding (GAIM)
Gas-assisted injection moulding (GAIM) is a process where an inert gas, almost always nitrogen, is used to assist in the injection of molten plastic into a mould. The nitrogen gas helps to fill the mould cavities more evenly and prevents the formation of voids or pockets of air. It also helps to reduce the amount of material required, as well as improve the surface finish of the moulded part.
The nitrogen gas required for this process is most efficiently generated using an onsite nitrogen generating system.
Stages in the Nitrogen Gas-Assisted Injection Moulding Process
The gas-assisted injection moulding process typically has four stages: pre-injection, gas injection, plastic injection, and post-injection.
- Pre-injection: The mould is heated and the gas is introduced into the mould cavity.
- Gas injection: The gas pressure is increased to push the molten plastic into the mould cavity.
- Plastic injection: The gas pressure is released and the molten plastic is injected into the mould cavity.
- Post-injection: The gas is vented from the mould cavity and the part is cooled.
Types of Gas-Assisted Injection Moulding
Below are a few variants of GAIM moulding where nitrogen gas is used:
- Low pressure gas-assisted injection moulding: In this process, the gas is injected at a low pressure into the molten plastic. This helps to reduce the amount of material required and improve the surface finish of the moulded part.
- High pressure gas-assisted injection moulding: In this process, the gas is injected at a high pressure into the molten plastic. This helps to improve the filling of the mould cavities and prevent the formation of voids or pockets of air.
- Microcellular gas-assisted injection moulding: In this process, the gas is injected at a very high pressure into the molten plastic. This helps to create small, evenly distributed bubbles in the moulded part. This can improve the strength and durability of the moulded part.
Benefits of Using Nitrogen Gas for Gas-Assisted Injection Moulding
There are several advantages to using nitrogen gas in the GAIM process. Nitrogen is non-reactive, so it will not corrode the mould or degrade the plastic. Nitrogen gas can be used in a variety of applications where gas-assisted injection moulding is used. It is also less expensive than other gases, such as argon.
For example, in the production of medical devices, nitrogen gas can be used to help prevent the formation of bubbles in the moulded part. Nitrogen gas can also be used in the automotive industry to assist in the moulding of plastic parts for cars and trucks.
Nitrogen Generating Systems for GAIM from Advanced Gas Technologies
Advanced Gas Technologies is a premier designer and supplier of state-of-the-art PSA and membrane nitrogen generators that are used for a wide range of industrial applications throughout North America. High-pressure and low-pressure nitrogen generating systems are available. Since 1994, we have helped our clients reduce their industrial nitrogen and oxygen costs by utilizing leading edge technologies such as on-site nitrogen and oxygen generating systems.