There are three ways to prepare a mesh with shell elements:
Generate a standard 3D mesh, and identify the membrane that represent the shell domain as a distinct boundary set. In Ansys Polydata, you will select this boundary set as the shell domain (as described in Inputs for Shell Contact Detection). The rest of the 3D mesh will be ignored.
If the parison (or sheet) is defined on the boundary of a 3D mesh (although only one boundary set is used, as described above), the mold must also be a 3D mesh. If the parison (or sheet) is a shell, then the mold must also be a shell (which will be extended into 3D, as described in Inputs for 2D and 3D Contact Detection). You cannot mix actual shell and 3D geometric entities for parison/sheet and molds.
Generate a mesh consisting of 2D elements in 3D space, representing the parison (or sheet) and the mold. In Ansys Polydata, you will select the subdomain representing the parison (or sheet) as the shell domain, and the subdomain representing the mold as the mold domain. In most cases, this method will be faster and easier than the previous method.
Generate a mesh consisting of 2D elements in 3D space for the mold. Then generate a mesh consisting of 2D elements in the 2D plane, solve a 2D axisymmetric extrusion simulation, create the circular shell mesh for the membrane from the results, and merge this mesh with the mesh for the mold. The procedure is as follows:
Set up the 2D axisymmetric extrusion simulation.
Create a postprocessor sub-task to calculate the parison thickness (as described in Parison Thickness).
In the Parison thickness menu, select Create transfer files for shell blow molding and define the parameters for the shell mesh generation.
Create transfer files for shell blow molding
The parameters you can modify are as follows:
Mesh filename: To specify the name of the file to which the shell mesh will be written at the end of the Ansys Polyflow simulation, select Modify MSH filename.
CSV filename: Select Modify CSV filename to specify the name of the comma-separated variable (CSV) file to which the thickness distribution and other results will be written at the end of the Ansys Polyflow simulation.
Number of mesh elements in the axial direction: By default, the number of elements in the axial direction is the same as in the current 2D mesh. Select Modify no. of elements in axial direction to modify this number.
Number of mesh elements in the tangential direction: Select Modify no. of elements in azimuthal direction to specify the number of elements in the tangential (azimuthal) direction.
Sector angle: Select Modify angle of generation to specify which sector of a circle is to be generated for the membrane (for example,
, 
, or a full 
circle). Element type: Select Switch to triangular elements for shell mesh to specify triangular elements. Select Switch to quadrilateral elements for shell mesh to specify quadrilateral elements.
Border for membrane: The creation of the membrane is based on a border, either the internal or the external border of the 2D axisymmetric mesh. Select Specify generation line to specify this border. Mesh generation on the basis of the external border is recommended, but if the 2D axisymmetric parison is very thin, with a relatively large radius, the specific choice is not significant.
Save the data file, exit from Ansys Polydata, and compute a solution with Ansys Polyflow. The shell mesh file and CSV file will be saved with the names that you specified.
In the Ansys Polydata session for your 3D simulation, select Combine mesh files to use Ansys Polyfuse to combine the shell mesh and the 3D mesh for the mold. See Combining Meshes with Ansys Polyfuse for information about combining meshes.
When you define the fluid layers representing the polymer in the mold (see Inputs for Shell Contact Detection), you can specify the initial thickness distribution by reading the data from the CSV file.
Note that Ansys Polyflow currently does not allow the parison/sheet and mold shells to be closed on themselves. That is, they both require a 1D boundary; a closed sphere is not acceptable. So-called waterproof parison/sheet or mold shells are not allowed, and cannot be set up in Ansys Polydata.