Interface conductance is a measure of the rate of heat transfer across the surfaces represented by inserts and parting planes.
The higher the rate of heat flow for a given temperature and area, the larger the interface conductance. If there is ineffective heat transfer due to air gaps, for example, the interface conductance value is very small.
Interface conductance is an optional attribute that you can assign to a mold insert or parting plane for a Cool analysis. Where insert surfaces have low values of interface conductance to represent assembly clearances, the temperature difference shows the difference in temperature from one side of the gap to the other. Where inserts directly contact the plastic, the insert temperatures are the same as the plastic.
The interface conductance value is determined primarily by the finish (smoothness) of the interface and the fit of the two metal surfaces. For inserts that have a good contact with the main mold material, it is not necessary to assign an interface conductance because the analysis program assumes a high value. Furthermore, insert surfaces directly in contact with plastic surfaces are assumed to have a very high value of interface conductance and any values that you assign to such surfaces will be ignored.
| Contact Type | Contact Pressure [MPa] | Surface Finish [µm] | Thermal Conductance [W/m2C] +/- 10% |
|---|---|---|---|
| Steel/Air/Steel (no gap) | 0 | Normal grinding | 2500 |
| Steel/Air/Steel (no gap) | 7 | Normal grinding | 21000 |
| Steel/Air/Steel (no gap) | 15 | Normal grinding | 38000 |
| Steel/Air/Steel (0.5 mm gap) | N/A | N/A | 50 |
| Steel/Air/Steel (1.0 mm gap) | N/A | N/A | 25 |
| Steel/Grease/Steel (Ejector pin or sliding core) | 0 | Lapped 2µm radial gap | 75000 |
| Steel/Grease/Steel (Ejector pin or sliding core) | 0 | Lapped 5µm radial gap | 30000 |
| BeCu/Air/Steel (T/C = 130 W/mC) | 330 | Normal grinding | 3700000 |