Types of cooling channels
Cooling-channel configurations can be serial or parallel. Both configurations are illustrated in Figure 1 below.
FIGURE 1. Cooling-channel configurations
Parallel cooling channels
Parallel cooling channels are drilled straight through from a supply manifold to a collection manifold. Due to the flow characteristics of the parallel design, the flow rate along various cooling channels may be different, depending on the flow resistance of each individual cooling channel. These varying flow rates in turn cause the heat transfer efficiency of the cooling channels to vary from one to another. As a result, cooling of the mold may not be uniform with a parallel cooling-channel configuration.
Typically, the cavity and core sides of the mold each have their own system of parallel cooling channels. The number of cooling channels per system varies with the size and complexity of the mold.
Serial cooling channels
Cooling channels connected in a single loop from the coolant inlet to its outlet are called serial cooling channels. This type of cooling-channel configuration is the most commonly recommended and used. By design, if the cooling channels are uniform in size, the coolant can maintain its (preferably) turbulent flow rate through its entire length. Turbulent flow enables heat to be transferred more effectively. Heat transfer of coolant flow discusses this more thoroughly. However, you should take care to minimize the temperature rise of the coolant, since the coolant will collect all the heat along the entire cooling-channel path. In general, the temperature difference of the coolant at the inlet and the exit should be within 5ºC for general-purpose molds and 3ºC for precision molds. For large molds, more than one serial cooling channel may be required to assure Cooling-channel Configuration uniform coolant temperature and thus uniform mold cooling.