1. What is the Cooling Time Formula?

The cooling time formula estimates how long it takes for a molded part to cool sufficiently before ejection. It's based on the thickness of the part and the thermal diffusivity of the material.

2. How Does the Calculator Work?

The calculator uses the cooling time equation:

Where:

• \( \text{Thickness} \) — Wall thickness of the part (converted to meters)
• \( \text{Diffusivity} \) — Thermal diffusivity of the material (m²/s)
• \( \pi \) — Mathematical constant Pi (~3.1416)

Explanation: The equation shows that cooling time increases with the square of thickness and decreases with higher thermal diffusivity.

3. Importance of Cooling Time Calculation

Details: Accurate cooling time estimation is crucial for optimizing injection molding cycle times, ensuring part quality, and preventing defects like warpage or sink marks.

4. Using the Calculator

Tips: Enter thickness in millimeters and thermal diffusivity in m²/s. All values must be valid (thickness > 0, diffusivity > 0).

5. Frequently Asked Questions (FAQ)

Q1: What is thermal diffusivity?
A: Thermal diffusivity is a material property that describes how quickly heat diffuses through a material. It's calculated as thermal conductivity divided by density and specific heat capacity.

Q2: How does wall thickness affect cooling time?
A: Cooling time increases with the square of wall thickness. Doubling the wall thickness quadruples the cooling time.

Q3: What are typical diffusivity values for plastics?
A: Most plastics have thermal diffusivity in the range of 0.1 × 10⁻⁶ to 0.2 × 10⁻⁶ m²/s.

Q4: Does this account for cooling channel design?
A: No, this is a basic calculation. Actual cooling times may vary based on mold temperature, coolant flow, and cooling channel layout.

Q5: How accurate is this calculation?
A: It provides a theoretical minimum cooling time. Real-world cooling times may be longer due to practical factors like mold design and processing conditions.