Gas-assisted injection molding (GAIM) is a type of injection molding that uses inert gas to create hollow part walls. This leads to lightweight parts that use less material than conventional injection molding, but that maintain their strength and have a better surface finish. GAIM is used in a wide variety of industries to create lightweight and strong parts while saving on material.
This article will discuss the gas-assisted injection molding process, how it works, materials, application, advantages, and disadvantages.
What Is Gas-Assisted Injection Molding?
Gas-assisted injection molding (GAIM) is a manufacturing process in which molten plastic and inert gases are injected into a mold to create 3D parts with channels in the part walls. The process is similar to conventional thermoplastic injection molding but additionally injects inert gas into the mold to create hollows or channels in the walls of the plastic part.
Gas-assisted injection molding produces lightweight parts that retain most of their strength. Parts are generally cheaper than those made with injection molding due to using less material per part. However, gas-assisted injection molding is not suitable for transparent materials, requires more complex molds, as well as high initial costs due to the specialized equipment required.
What Is Gas-Assisted Injection Molding For?
Gas-assisted injection molding is a manufacturing process used for creating 3D plastic parts with hollow walls. These parts are lightweight with high strength, excellent surface finish, and dimensional accuracy.
When To Use Gas-Assist Injection Molding?
Gas-assisted injection molding is used when lightweight 3D plastic parts with high strength, excellent accuracy, and surface finish are required. It is also used for parts that contain hollow sections, or when material needs to be saved.
How Is Gas-Assisted Injection Molding Used in Manufacturing?
Gas-assisted injection molding is a manufacturing process that uses inert gas as part of the injection molding process to create 3D plastic parts with hollow walls or channels. It is used to create strong, but more lightweight parts than those produced by conventional injection molding. Additionally, GAIM produces parts with exceptional surface quality and high dimensional accuracy, all while using less material than conventional injection molding.
What Is the Gas-Assisted Injection Molding Process?
The gas-assisted injection molding process consists of the following steps:
Clamp the mold together, ready to receive the molten plastic.
Feed the plastic pellets into the hopper, and heat until melted.
Inject the molten plastic into the mold. In GAIM, only around 70–80% of the mold gets filled with the molten plastic.
Inject the inert gas into the mold, which forms a bubble in the molten plastic, pressing it evenly against the sides of the mold.
As the plastic starts to cool, it contracts, reducing pressure in the mold, and potentially resulting in deformation and inaccuracies. In this stage, more gas is injected to maintain even pressure across the part.
Once the part has cooled and hardened, it gets ejected from the mold to make space for the next part.
How Long Does the Gas-Assisted Injection Molding Process Take?
The gas-assisted injection molding process can take anywhere from a few seconds to several minutes, depending on the material type, part geometry, and wall thickness. Compared to conventional injection molding, gas-assisted injection molding has an extra step in which gas is injected into the part wall and pressure is maintained until the part has sufficiently cooled. However, even with this additional step, gas-assisted injection molding is generally quicker than conventional molding, as the hollow walls need less time to cool and harden.
How Does Gas-Assisted Injection Molding Differ From Other Molding Process Types?
Gas-assisted injection molding is similar to conventional injection molding in that molten thermoplastics are injected into a mold to create a 3D plastic part. Where gas-assisted injection molding differs from conventional injection molding, is that inert gas is also injected into the mold with the molten plastic, resulting in channels or hollow walls.
Gas-assisted injection molding uses less pressure than conventional injection molding, as there is less material to fit into all the details of the mold. The low-viscosity gas requires less pressure than the material it replaces. Gas-assisted injection molding also spreads the pressure within the mold more uniformly, resulting in better accuracy, a smoother surface finish, and fewer internal stresses in the final product.
To learn more, see our full guide on Other Molding Process Types.
Is Gas-Assisted Injection Molding Better Than Injection Molding?
Gas-assisted injection molding uses inert gas within the injection molding process to create hollows or channels within part walls. When compared to conventional injection molding, this results in parts that have better dimensional accuracy, better surface finish, and that are cheaper and lighter in weight.
This comes at the cost of being a more complex process, requiring skilled machine operators and higher initial equipment and tooling costs.
To learn more, see our full guide on Injection Molding Processes.
What Molds Are Used for Gas-Assisted Injection Molding?
Molds for gas-assisted injection molding are typically made from aluminum, hardened steel, or beryllium-copper alloy. Steel molds are the most durable, but also the most expensive. Aluminum is an economical option but doesn’t have the durability of steel. Beryllium-copper alloy is used for fast heat transfer, which reduces cycle time and improves the part’s surface finish.
These molds are custom-designed and manufactured. They come in two or more sections to allow for ejecting the part after it has been produced, and they also have inlet and outlet holes for gas to pass into the mold.
What Are the Materials Used for Gas-Assisted Injection Molding?
Gas-assisted injection molding can use a range of thermoplastics, including:
Polybutylene Terephthalate (PBT): Food-safe, with excellent heat and UV resistance, and is used in medical and food processing applications.
Polypropylene (PP): Has good strength, good chemical and heat resistance, and low electrical conductivity, but is susceptible to UV degradation.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
cURL Too many subrequests.
XTJ es un fabricante OEM líder dedicado a ofrecer soluciones de fabricación integral desde prototipos hasta producción. Nos enorgullece ser una empresa certificada con ISO 9001 en gestión de calidad y estamos decididos a crear valor en cada relación con el cliente. Lo logramos mediante colaboración, innovación, mejoras en los procesos y una mano de obra excepcional.
