Hi DmArcher,

It would help to know the boundary conditions.  I assume the heat transfer you are interested in is vertical. If the BCs on the four sides are identical and the loads on the top and bottom faces are symmetric, then you could slice the geometry with 2 planes and discard 3/4 of the geometry by applying a Symmetry BC on the cut faces. That will free up a lot of nodes!  If the BC on the four sides is insulated and the top and bottom BCs are uniform across the face, this 3D problem collapses to a 1D problem and you only need one element in the plane!

I see that Bonded Contact is being used to connect the four layers together. If you don’t need Contact to add an extra thermal resistance, you would be better off using Shared Topology to have the elements on each side of the interface grab the same nodes. In SpaceClaim, on the Workbench tab, click the Share button. Then in Mechanical, delete all the contacts.

Once you have shared topology, all the layers will have the same element density in the plane. Add a Sizing mesh control and have the Geometry filter set to Edges. Pick the 4 vertical edges in one layer and set the control to Number of Elements. Repeat for the other three layers. Now you can control the number of elements in each layer.