The hardest problem in physical AI may be the magnet, not the model

Actuators account for 40% to 60% of a humanoid robot’s bill of materials and China refines roughly 90% of the rare earth magnets inside them, which makes the components rather than the models the limit on scale. Europe has a 2030 cap on single country supply under the Critical Raw Materials Act, and one company, Schaeffler, building the actuators at volume.

The hardest problem in physical AI is not the AI. Actuators are in short supply from a small pool of qualified manufacturers, and new capacity takes years, not quarters, Nate Evans wrote in Unite.ai.

The argument arrives with an interest attached. Evans cofounded Fictiv, a manufacturing sourcing platform the Japanese components supplier MISUMI bought for $350M, and now heads MISUMI AI.

The column drops the point just as it gets useful. Actuators are 40% to 60% of a humanoid robot’s bill of materials, McKinsey found, and the gearbox is 30% to 50% of the actuator.

That gearbox is where the queue forms. Harmonic and strain wave drives come from a short list including Harmonic Drive and Nabtesco, and qualification cycles are long.

Inside the motor sits the harder dependency. Every high torque joint needs a neodymium magnet, and China holds about 90% of the processing capacity for rare earth magnets.

The mining figure is lower and less alarming. China accounts for roughly 69% of extraction, so refining rather than ore is what binds.

Europe has written a law about exactly this. Light and heavy rare earths sit on the strategic raw materials list, with a 2030 target that no single third country supplies more than 65% of consumption.

The Critical Raw Materials Act also reaches the robot itself. Articles 28 and 29 name industrial robots directly, and from 2028 magnets above 0.2kg need a label, a digital record and a recycled content figure.

Europe’s industrial answer is currently one company. Schaeffler invested in Humanoid, the London startup that raised $152M in July, and Bosch builds the robots.

Schaeffler also sells the joints. It is preferred supplier for more than half of Humanoid’s joint actuators under an agreement running to 2031, covering a seven-digit number of units.

It is buying as well as supplying. Schaeffler will put a four-digit number of the robots into its own plants by 2032, starting at Herzogenaurach in December. TNW has argued Europe could win on deployment despite China holding 63% of the hardware chain.

Which is where the column’s remedy runs out. An actuator assembled in Herzogenaurach still contains a magnet refined in China, and no amount of supplier qualification changes that.

The gap is a policy one rather than a purchasing one. Europe has a 65% cap dated 2030, a labelling regime dated 2028, and almost no refining capacity to meet either.