Dynacast has introduced a magnesium multi-slide die casting technology capable of producing strong, lightweight components with complex geometries. While drawing on the company's existing zinc multi-slide die casting technology, the new process incorporates "major refinements" for casting magnesium. The result is a high-speed process that tightly controls temperature and yields complex, thin-walled components for the telecommunications, automotive, and information technology industries.

According to the company, the key to the process is a proprietary 4-slide crosshead machine, designed and built to take advantage of the inherent material benefits of AZ91 high-purity magnesium alloy. By using four precision-ground sliders, running in similarly prepared channels positioned at 90 to each other in a cruciform configuration, the 4-slide method overcomes part-to-part inconsistencies resulting from wear of moving die parts. Die blocks can be mounted onto the faces of the sliders, with the option of using up to four. Free of complex moving parts, the fully integrated unit is capable of operating at high speeds and "exceptional" levels of repeatability and precision throughout the life of the tool. The complexity achieved by the process can be achieved alternatively only through multi-piece assemblies, the company says.

"Manufacturers of telecommunications, automotive, and handheld electronic systems, in particular, are seeking strong yet lightweight components of ever increasing complexity, complemented by properties such as RFI shielding and cosmetic finishes," says says David Simas, VP Marketing, Dynacast, Inc. "This specialized technology will set new standards for such components backed by a global design capability."

Magnesium has the lowest density of all structural metals, a property that suits it to applications requiring weight savings. Nearly as light as plastic, magnesium is nevertheless stronger and more rigid than plastic, while also exhibiting a high degree of EMI/RFI shielding, durability, and heat dissipation. Its high fluidity, important for thin-walled or intricate parts, enables the metal to completely fill the die cavity before it freezes (solidifies). Also, because magnesium has low volumetric specific heat, castings cool faster, contributing to faster cycle times. The low heat content means that less energy is required to reach casting temperature than in the case of aluminum; it also causes less thermal distortion.

Current and potential applications for magnesium parts include handheld electronic devices, such as mobile phones, mini-disc players, cameras, and personal digital assistants (PDAs); and weight-saving automotive components.