If you encounter convergence difficulties in a 3D extrusion problem, you should apply evolution to the moving boundaries. For more information about these techniques, see Convergence Strategies.

As discussed in Discontinuity of the Normal Direction, the line kinematic condition is recommended over the default surface kinematic condition. To enable the line kinematic condition, select Line kinematic condition in the Numerical parameters menu or in the Global remeshing menu.

  Line kinematic condition

As mentioned in Surface Kinematic Condition, if you use the surface kinematic condition for handling discontinuities in the normal direction (rather than the recommended line kinematic condition), it is important for the mesh to have a sufficient number of boundary sets to allow for proper piecewise definition of the free surface around edges.