Hardware

Thermal Coefficient of Expansion

The thermal coefficient of expansion (CTE) is a material property quantifying the fractional change in a component's dimensions per degree of temperature change, typically expressed in parts per million per kelvin. In robot design, CTE mismatch between joined materials, such as aluminum structures and carbon fiber or steel, induces stress and geometric distortion as temperature varies, degrading kinematic calibration and repeatability. Precision machines counter this with low-CTE materials, thermal symmetry, and warm-up compensation.

Why it matters for physical AI

Robots that hold sub-millimeter accuracy across shifts and seasons need thermally aware mechanical design, since calibration drift from expansion silently erodes the precision that vision-based policies and fixtures assume.