China’s halt this month on exports of magnets containing heavy rare earth metals has affected Tesla’s plans to manufacture Optimus robots.
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Elon Musk Warns Rare Earth Magnet Shortage May Delay Tesla’s Robots
China’s halt this month on exports of magnets containing heavy rare earth metals has affected Tesla’s plans to manufacture Optimus robots.
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Elon Musk at the White House this month.Credit...Eric Lee/The New York Times
By
Keith Bradsher
Reporting from Shanghai
April 23, 2025Updated 10:28 a.m. ET
Elon Musk, the chief executive of Tesla, said on Tuesday that China’s halt on exports of certain magnets was affecting his plans to build humanoid robots, in the clearest signal yet that China’s action is beginning to affect big American businesses.
China this month
suspended exports to any country of so-called heavy rare earth metals and magnets made from them, as part of its retaliation for President Trump’s increases in tariffs on U.S. imports of Chinese goods. The Chinese government has stopped allowing shipments until it can devise an export license system.
China produces the entire world’s supply of heavy rare earth metals, from ore mined in China and Myanmar, and 90 percent of magnets made with these metals. Japan produces the rest of the magnets, but uses raw materials from China.
Rare earth magnets are used inside electric motors that need to fit in compact spaces. Robots have many small electric motors, typically one or more for each joint, that each require a magnet. The use of the heavy rare earths in most of these magnets keeps them from overheating and malfunctioning when motors are confined in small spaces.
Tesla’s humanoid robot Optimus at an exhibition booth during the World Artificial Intelligence Conference in Shanghai last year.Credit...Agence France-Presse — Getty Images
Rare earth magnets are up to 15 times as powerful as conventional iron magnets of the same size. If traces of heavy rare earth metals are included in a magnet’s material, it can maintain its magnetic force even at temperatures that would boil water.
Mr. Musk said during Tesla’s earnings call on Tuesday that the company’s Optimus humanoid robots have electric motors in their arms that operate in a confined space and require the special magnets.
“That’s more affected by the supply chain, by basically China requiring an export license to send out anywhere with magnets, so we’re working through that with China,” he said.
A shortage in the supply of the magnets could slow the production of Optimus robots, Mr. Musk said.
Tesla is investing billions of dollars in the
Optimus robots, which Mr. Musk has said will someday perform many daily functions. At an
event last fall, he showed the robots serving drinks and unloading groceries from a car.
Mr. Musk also said on the earnings call that he would reduce the time he spends as an
adviser to President Trump to focus more on Tesla, which reported a drastic decline in profits.
Cars, factory robots, missiles, smart bombs, stealth fighters and many other products also require rare earth magnets made partly with heavy rare earth metals.
Yang Jie, an export control lawyer at Huiye, a Shanghai law firm, said that China’s regulations call for the Ministry of Commerce to devise an export control protocol within 45 working days of its announcement, which was on April 4.
But issuing export licenses for shipments to the United States could take much longer, given recent tensions between the two countries, he warned. “Six months for rare earth exports is my personal estimate of the fastest time — the actual time may be far more than six months,” he said.
Not all manufacturers of humanoid robots may be as affected as Tesla.
Jonathan Hurst, the chief robot officer at Agility Robotics, another American maker of humanoid robots, said robots can be designed to minimize their need for magnets made with heavy rare earth metals.
Agility has designed its robots with slightly less human proportions than the Optimus robots. This provides more room for the electric motors, Mr. Hurst said. As a result, the motors in many of Agility’s robots may not overheat.
Since the April 4 ban, China’s customs agents have been checking exports carefully to make sure that no magnets with heavy rare earths are allowed to leave the country, industry executives said.
