Work out cooling time for moulding instantly with clear inputs, formula shown and shareable results.
Cooling time follows one-dimensional transient conduction through the wall: t = h² / (pi² alpha) x ln[(4/pi)(Tmelt - Tmould) / (Teject - Tmould)], with thermal diffusivity alpha around 0.09 mm²/s for common polyolefins. Because thickness is squared, cooling dominates the cycle and a small reduction in wall thickness pays back far more than colder water.
Cooling time
t = h² / (pi² x alpha) x ln[(4/pi) x (Tmelt - Tmould) / (Teject - Tmould)]
t = h² / (pi² x alpha) x ln[(4/pi) x (Tmelt - Tmould) / (Teject - Tmould)]. Cooling time follows one-dimensional transient conduction through the wall: t = h² / (pi² alpha) x ln[(4/pi)(Tmelt - Tmould) / (Teject - Tmould)], with thermal diffusivity alpha around 0.09 mm²/s for common polyolefins.
Injection and packing take a second or two, but heat has to conduct out through the wall, and that time grows with the square of thickness. Thick sections are the usual reason a cycle is long.
This calculator takes 4 inputs: Maximum wall thickness, Melt temperature, Mould wall temperature, Ejection temperature. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.