When the mold temperature for a part has been established, an appropriate coolant can be selected. Coolant temperatures are typically 10ºC cooler than the mold surface.
| Coolant | Temperature |
|---|---|
| Ordinary water from mains or a cooling tower | 20 to 25°C |
| Cold water from a chiller | above 10°C |
| Water mixed with antifreeze (usually glycol) from a chiller | -5°C |
| Oil-normally from a heater/circulator unit | 80°C or above |
Adding glycol to the coolant will raise its viscosity, resulting in a higher pumping pressure being required, or a lower flow rate. Using a chilled water and glycol mix may be less effective than a well designed cooling circuit with plain tower water circulating at the optimum flow rate. Oil is used only when very high mold temperatures are required.