Thermal Expansion Calculator
Determine the dimensional change of any component (part, mold, insert) caused by a temperature variation. The calculator computes linear elongation based on the initial dimension, temperature change and material expansion coefficient.
Input Parameters
Results
Fill in the data and click Calculate
ARGUS automatically accounts for thermal expansion in all dimensional calculations
Thermal expansion affects the dimensions of the part, mold and machine — ARGUS balances these changes automatically within the full process context.
How do we calculate thermal expansion?
Thermal expansion is the change in dimensions of a solid body due to a temperature change. In injection molding it affects the part (shrinkage during cooling), the mold (expansion during heating) and machine components. Correctly accounting for thermal expansion is critical for dimensional precision.
The calculator applies the linear thermal expansion model — the simplest and most widely used model in engineering practice.
Lfinal = L₀ + ΔL
ΔL — dimensional change [mm]
L₀ — initial dimension [mm]
α — expansion coefficient [1/K]
ΔT — temperature change [°C = K]
Thermal expansion coefficients differ dramatically between metals and plastics. Steel: 11–12×10⁻⁶/K, aluminum: 23×10⁻⁶/K, thermoplastics: 50–200×10⁻⁶/K. This means plastics expand 5–20× more than metals for the same temperature change.
Expansion Coefficients
Aluminum — 23 × 10⁻⁶/K
PP — 100–150 × 10⁻⁶/K
ABS — 70–100 × 10⁻⁶/K
PA6 — 80–100 × 10⁻⁶/K
PC — 65–70 × 10⁻⁶/K
PA6-GF30 — 20–40 × 10⁻⁶/K (in GF direction)
Glass-fiber-reinforced materials exhibit strong expansion anisotropy — in the fiber orientation direction the coefficient is 3–5× lower than in the perpendicular direction. This causes warpage during cooling and must be considered in mold design.
Applications in Injection Molding
Most common uses of expansion calculations: dimensional compensation of mold (core/cavity), calculating clearances in slide mechanisms at operating temperature, verifying fit of mold inserts, thermal stress analysis in mold components, calculating part shrinkage after cooling to ambient temperature.
ARGUS automatically accounts for thermal expansion in all dimensional calculations
See for yourself — book a presentation and explore the full dimensional model in ARGUS.