What is Magnesium Thixomolding?
Thixomolding is a semi-solid Magnesium casting process and near net shape variant of die casting. Combining the advantages of casting and forging, thixomolding is named after the fluid property thixotropy which makes the process possible.
Thixomolding occurs at a temperature that puts the Magnesium material between 30-65% solid. The process is typically used to produce high-performance components, such as structural medical and aerospace parts, pressure containments, engine mounts and blocks, and oil pump filter housings.
How Does Magnesium Thixomolding Work?
Magnesium thixomolding uses a machine similar to an injection molding or die casting press. In a single-step process, room temperature Magnesium alloy chips are fed into the back end of a heated barrel through a volumetric feeder. The barrel is maintained under an argon atmosphere to prevent oxidation of the Magnesium chips.
A screw conveyor located inside the barrel feeds the Magnesium chips forward as they are heated into the semi-solid temperature range. The screw rotation provides the necessary shearing force for semi-solid thixomolding. Once enough slurry has accumulated, the screw moves forward to inject the slurry into a Steel die.
Advantages of Magnesium Thixomolding
Magnesium thixomolding offers many advantages, some of which include:
Strength: Magnesium has the highest strength-to-weight ratio of any commonly available material.
Lightweight: Despite its strength, Magnesium is the lightest of all structural materials — weighing only two-thirds as much as Aluminum and only one-fourth as much as Zinc or Steel.
Extended tool life: Magnesium’s low affinity for iron and lower heat of fusion results in extended die life.
Dimensional stability: Magnesium offers high ductility, excellent dimensional stability, and can be molded to finished tolerances with walls as thin as 1 millimeter.
High thermal conductivity: Magnesium disperses heat quickly, making it ideal for electronic enclosures, heat sinks, and other items where heat must be dissipated.
Dampening capacity: Magnesium provides high energy absorportion to greatly reduce noise and vibration.
Machinability: While many Magnesium parts require no machining or finishing, Magnesium is recognized as the easiest of all structural metals to machine.
Finishing: A wide range of finishes are available for decorative or protective purposes.