How a humanoid robot is made

Neodymium and praseodymium metal, the main rare-earth input to the magnet alloy.

Heavy rare earths for coercivity at rotor temperature, put in by grain-boundary diffusion (or alloyed in on older grades).

Alloy steel bar and forgings machined into the flexspline, circular spline and gear trains.

Through-hardening bearing steel (100Cr6 = SAE 52100 = SUJ2 class) for bearing rings and the reducer's output bearing.

Hall or magnetoresistive absolute position sensor IC, two per joint.

Si MOSFETs today, GaN entering: six switches per three-phase joint inverter.

300 mm silicon wafers for the SoC and the image sensors.

905 nm laser diode and receiver inside the lidar.

Melting and strip casting of Nd-Fe-B alloy, 200 to 400 um flakes; hydrogen decrepitation to under 2 mm; jet milling to 2 to 5 um. Output: aligned fine powder.

Align in field and press; sinter 1000 to 1100 C; two-stage anneal 850 to 950 C and 400 to 600 C; machine; grain-boundary diffusion of Dy or Tb for coercivity; nickel or epoxy coat; magnetize. Output: sintered NdFeB segments or ring, grade N42SH to N45UH class for joint rotors.

Electrical-steel lamination stamping and stacking; copper winding with high fill factor; rotor ring with surface magnets; no housing or bearing (the joint supplies them). Output: frameless PMSM, internal rotor, 48 V bus, 50 to 115 mm outer diameter.

Harmonic: flexspline, circular spline and wave generator machined from steel, teeth cut, heat treated, assembled with an output crossed-roller bearing; planetary: two-stage gear train; cycloidal: eccentric cam and pin ring. Output: reducer unit, 30:1 to 160:1 harmonic or 2-stage planetary.

Ring forging in 100Cr6-class bearing steel, turning, through-hardening to 58 to 64 HRC, grinding, crossed-roller assembly. Output: crossed roller bearing, 50 to 70 mm bore.

Magnetic absolute sensor IC (Hall or magnetoresistive) on a PCB facing a magnet ring; one on the motor shaft for commutation, one on the joint output for true angle. Output: two encoders per joint (dual encoder).

Three-phase inverter (3 half-bridges = 6 switches) + gate driver + MCU on a round PCB inside the joint; 15 to 55 V bus. Output: joint drive board.

Motor + reducer + output bearing + two encoders + driver assembled into one hollow-shaft module; cables routed through the bore. Output: one actuated joint.

LFP (hydrothermal or solid state) or NMC precursor to cathode powder; graphite anode. Output: active materials.

Electrode mixing, coating, drying, calendering, slitting, stacking or winding, welding, electrolyte fill, sealing, formation. Output: pouch or cylindrical cell, about 3.6 V nominal (13S x 3.6 V matches the G1 54 V charger).

13-cell series string (G1) with BMS, quick-release housing and connector; UN38.3 transport test; pack-level protection layers. Output: 0.42 to 2.25 kWh pack, 48 to 67 V class.

Leading-edge logic fab of the Blackwell GPU + Arm Neoverse V3AE CPU die. Output: Thor die.

LPDDR5X die fab and packaging, 128 GB on the T5000 module. Output: LPDDR5X packages.

SoC packaging, module PCB assembly with DRAM, 699-pin connector, 100 x 87 mm. Output: Jetson T5000 module ($2,999 at 1,000 units) or IGX Thor board.

Carrier board, thermal design, safety MCU; integrated into the torso or head. Output: robot compute (NEO Cortex; Digit 5 IGX Thor + Halos; Optimus FSD computer).

CMOS image sensor fab (global-shutter IR pair + rolling-shutter RGB in the D435i). Output: image sensor die.

Lens, sensor board, IR projector (depth cameras), calibration. Output: depth camera (RealSense D435i on G1) or stereo fisheye pair (NEO, 8.85 MP, 90 Hz).

905 nm laser diode, detector, non-repetitive scanner, IMU, sealed IP67 housing. Output: Livox Mid-360, 265 g, 6.5 W, 200k points/s.

Cameras in head (and palms on Figure 03); lidar on the head (Unitree). Output: perception set.

Joint modules, the battery pack, the compute and the perception set assembled into one actuated humanoid robot.