The tendency of materials to change dimension with temperature, characterized by the coefficient of thermal expansion (CTE), critical for predicting warping and fit changes in printed parts.
ΔL = α × L₀ × ΔT. Typical polymer CTEs: PLA 68 µm/m·K, ABS 90 µm/m·K, PEEK 47 µm/m·K vs. steel 12 µm/m·K, aluminum 23 µm/m·K. Mismatch in CTE between printed part and metal insert/fastener causes loosening or cracking under thermal cycling. FDM parts are also anisotropic in CTE.
Size clearance fits for the highest operating temperature. For metal inserts in polymer: ΔD = α_polymer × D × ΔT. Heated enclosures (electronics, automotive) need explicit thermal analysis. Minimize warping: use heated bed, enclosure, proper first-layer adhesion, and slow cool-down.
Ignoring CTE mismatch in multi-material assemblies causes joint failure after thermal cycling. ABS shrinks significantly (~0.8%) during cooling: always use heated bed and enclosure. Bimetallic effect in anisotropic FDM parts causes curvature on cooling if top/bottom layers differ.
Related terms: Clearance Fit, Tolerance, Dimensional Accuracy, Assembly Clearance
| Field | engineering |
|---|---|
| Also called | CTE, coefficient of thermal expansion, thermal distortion |
| Source | EDi Brain: rules-core |
Engineer, author of The Big Book of 3D Printing and additive manufacturing expert