In some cases, you may need to combine several disconnected parts in order to simulate a given process. For example, blow molding and thermoforming simulations involve a parison and molds, and extruders and batch mixers that use the mesh superposition technique (see Flows with Internal Moving Parts) will also involve multiple parts. In such cases, you can create a separate mesh file for each part, combine them using Ansys Polyfuse, and then perform the simulation on the entire model.

In cases such as blow molding, for example, the number of elements defined in the mold does not significantly affect the computational time. You can therefore generate a very fine mesh for these solid parts in order to get an accurate definition of their shape. Unfortunately, writing a mesh with a large number of elements for a complex geometry may take a significant amount of time in your mesh generator. Each time you want to modify the parison shape or discretization, you will need to spend a lot of time generating the mesh for the mold as well. If, however, you create the mesh for the mold only once and save it to a separate file, you can then make modifications to the parison mesh without regenerating the mold mesh. Similarly, for an extruder modeled with the mesh superposition technique, you can generate the mesh for the screw elements once, and then modify the mesh for the barrel as often as you need.