Mitsubishi Electric Corporation Magnesium Research Center of Kumamoto University, TOHO KINZOKU CO., LTD., and the Japan Aerospace Exploration Agency  announced today the 3D printing industry’s first1  high-precision additive manufacturing technology for using magnesium alloys in a wire-laser metal 3D printer via the directed energy deposition  method, marking a significant leap forward in industrial manufacturing. Unlocking the potential to process magnesium alloys with unparalleled precision and complexity will pave the way for rocket, automobile, aircraft, etc. components that are lighter and stronger than those made of iron or aluminum, leading to improved fuel efficiency and, in the case of rockets, reduced production costs. In addition, the envisioned production processes based on a wire-laser metal 3D printer will be more energy efficient and generate fewer greenhouse gas emissions compared to conventional processes, promising to deliver low-impact solutions for increased sustainability

Since September 2022, the consortium members have been conducting joint research (Research on Laser Wire DED Method AM Process Technology Using Magnesium Alloy Wire) under the framework of JAXA’s Innovative Future Space Transport System Research and Development Program, 3 working to reduce the weight of rockets and thereby drastically cut costs. In addition to rockets, the need for weight reduction has increased in recent years due to factors including the shift to electric vehicles and the growing demand for commercial aircraft, so magnesium alloys are attracting attention in many fields. But magnesium alloys are typically processed by die casting, 4 making it difficult to create structures with hollow interiors. Also the mainstream powder bed fusion (PBF) 5 method for AM, which uses heat to selectively melt metal powder, can lead to degradation through oxidation or dust explosions, posing a problem for safe manufacturing.

In response, the consortium combined Mitsubishi Electric's metal 3D printer, which uses the wire-laser DED method and metal wire instead of metal powder as a material, with a highly nonflammable KUMADAI heatresistant magnesium alloy6 developed by MRC. In tests, Mitsubishi Electric repeated the molding process with
the KUMADAI heat-resistant magnesium alloy produced by TOHO KINZOKU using advanced wire drawing technology. The result is a new technology that uses a magnesium-alloy wire as an AM material and precise temperature control to prevent combustion.

Based on JAXA’s evaluation of AM production samples produced with this new technology, it is estimated that some rocket parts could be made up to about 20% lighter than those with traditional aluminum alloy structures.

Furthermore, it is believed that the same process could be widely applied to other fields where weight reduction is also required, including various transportation equipment and robotic components. Accordingly, further research and development targeting applications in various industrial fields will be conducted in parallel with Mitsubishi Electric’s work to commercialize the technology in a wire-laser DED metal 3D printer by around 2029.

AM of magnesium-alloy wire combines high workability and strength

• MRC studied many KUMADAI heat-resistant magnesium alloys to find a composition for AM that is flame-resistant even in wire form.
• TOHO KINZOKU established a technology for producing wire of any diameter and length for AM, and fabricated prototype wires that were extensively tested by Mitsubishi Electric, resulting in an optimum wire thickness and wire drawing process.

High-precision AM technology uses nonflammable magnesium-alloy wire

• Mitsubishi Electric has developed a technology for its wire laser DED metal 3D printer that precisely controls laser power and wire speed using computer  numerical control (CNC) to keep the processing area at a constant temperature. This enables magnesium alloys with a width of 3mm to be processed into any  shape with high precision and without burning.
• Unlike die casting, no mold is required, eliminating the cost of changing and replacing molds

Magnesium-alloy AM structure will lead to lighter rocket parts

• AM production samples achieve a high tensile strength of about 250 megapascals (MPa) at room temperature and about 220MPa at high temperatures around 200  degrees, equal to or better than conventional methods. Also, the samples have been shown to be heat resistant and nonflammable.
• In evaluating the samples’ applicability as rocket materials compared to conventional materials, JAXA found that the weight of rocket shell structures and  aerodynamic control fins could be significantly reduced by up to 20%.

AM processing does not generate greenhouse gases, supporting sustainability

• Magnesium alloys are lighter and stronger than aluminum and iron, so their use in automotive and aircraft components will contribute to greater fuel efficiency.
• Compared to machining from ingots, 7 minimized material waste will help improve energy efficiency in processing as well as conserve materials.
• The technology eliminates the use of sulfur hexafluoride (SF6), a greenhouse gas with a high global warming potential that is conventionally used as a shielding gas8 for magnesium-alloy casting, helping to significantly reduce greenhouse gas emissions.

 

Source:mitsubishielectric.com

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