Newly 3D printed metal could be used by Tesla to produce all-electric vehicles with just a few massive parts, thanks to two MIT students.
Announced very recently, the new sort of steel was created by MIT undergraduates and their graduate student mentor in Germany, not for the construction of the cars but for the die-casting molds that stamp them out in just a few distinct pieces.
MIT junior Ian Chen and Kyle Markland managed to produce a 3D-printable steel alloy inspired by a manufacturing approach called Giga-casting, popularized by carmaker Tesla and used to assemble the all-electric Model Y.
Chen and Markland's project is inspired by Gregory Olson, the Thermo-Calc Professor of Practice at MIT, who teaches Computational Materials Design.
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Olson is a world-renowned expert in computational materials science, which employs computer modeling and simulation to understand and design new materials. His methodology was used by Apple to develop the Apple Watch, and it piqued the interest of Tesla CEO Elon Musk.
“To get affordable electrical cars with good range, he had to make aluminum structures affordable,” says Olson, speaking of Musk.
“So he looked at the kind of die casting for little car models and said, ‘Why not scale it up? We’ll cast the whole car.’”
Olson's computational approach was used by Tesla for the aluminum that could be die cast — the metal casting process in which molten metal is poured into a mold to form objects.
Cars are typically constructed from hundreds of die-cast parts, such as engine cylinders, brackets, and other components, which are then assembled on an automated assembly line to form a vehicle. Instead, the Giga-casting process — named after the massive casting machines known as Giga Press — involves casting only two or three large automobile pieces, significantly reducing the process's complexity and associated costs.
The problem is, “when you scale up the process, the heat transfer is slower, and the cycle times are too long,” Olson says — that is, the liquid metal takes longer to cool, making the whole process less efficient and more costly.
A technique known as "conformal cooling" can be beneficial. Narrow channels follow or conform to the shape of the thing being cast in it, and coolant or water is run through them to speed cooling.
Olson's former student Charles Kuehmann, vice president of materials engineering at SpaceX and Tesla, corroborated the demand for stronger tool steel that is "printable" — a substance that could be fed into a 3-D printer to produce new dies with improved strength and thermal properties. If you try to print conventional steels, Olson claimed, "they are highly brittle and cracking-prone."
The team filed a U.S. patent application for the new printable die steel, and the next step is testing in casting die applications. While this was happening, Musk tweeted "Take Materials Science 101. You won’t regret it”
Chen, a student studying materials science and engineering, now knows for sure that he wants to pursue graduate study in the field of materials.
“This project has pushed me toward a more computationally driven materials area,” Chen says, “where computational models are used as a critical tool for materials design and analysis.”
“It feels great to have our work recognized by ASM,” Kyle Markland added. “Sometimes classwork can feel abstract or removed from the real world, and it’s a refreshing reminder that the project we did has recognition beyond just a class assignment.”