Injection molding · Process
Cooling Time Calculator
Estimate cooling time using a flat-wall heat-transfer model. This practical tool is an engineering estimate—validate decisions against machine, material, mold, and process data.
Decision chain
From estimate to the next check
- Thermal recordControlling wall, grade basis, melt, mold, and ejection temperatures
- Wall modelA comparative flat-wall estimate
- Process screenUse with total cycle and ejection requirement
- Trial validationCheck dimensions, stress, warp, surface, and release
Formula and method
The flat-wall estimate scales with wall thickness squared and thermal diffusivity.
Inputs and units
Enter measured or specified values in the displayed units. Keep units consistent; results are rounded for practical planning. This first release uses the displayed engineering units rather than a unit-switcher.
Worked example
With 3 mm wall, 0.12 mm²/s diffusivity, 240°C melt, 60°C mold, and 95°C ejection, the flat-wall estimate is about 14.28 s.
Use the controlling thermal inputs
Enter the thickest section likely to govern ejection, a grade-appropriate thermal-diffusivity value, and temperatures tied to the intended process. The ejection temperature must represent an acceptable part condition, not just a convenient target.
Use it to compare alternatives
The result is most useful when comparing wall thickness or thermal assumptions on the same basis. Follow with mold cooling design, trial data, or simulation before changing a production cooling target.
Know when the wall model breaks down
Ribs, bosses, corners, inserts, uneven cooling channels, and quality requirements can govern ejection even when a nominal flat-wall estimate looks favorable.
Interpretation, assumptions, and limitations
FAQ
Can I reduce cooling to the calculated number immediately?
No. Confirm ejection force, distortion, dimensions, stress, and surface quality through controlled trials or a validated process.
Next: circuit and thermal-control checks
After estimating part cooling time, use Mold Cooling & Thermal Control Tools to examine circuit flow, heat removal and measured water temperature rise.