Advanced Settings for Cool Solver

To open the advanced Cool solver settings:

1. In the PlasticsManager, expand Global Parameters, and double-click Cool.
2. In the Cool Parameters PropertyManager, click Solver Settings.

Cool Solver

The Cool solver iteratively calculates the transient thermal fields of the mold and cavity. For the first cycle, the mold temperature is the ambient temperature. For each subsequent cycle, the solver assigns the uniform melt temperature to be the initial part temperature, but obtains the mold initial temperature from the previous cycle.

Similar to a real injection molding machine, the cycle-averaged mold temperature converges to a steady-state value after a number of injection cycles.

For the solid analysis procedure, the Cool solver performs a conjugate heat transfer analysis in both the polymer and mold domains using a finite volume method.

For the shell analysis procedure, the Cool solver calculates the temperature fields:
• In the polymer, by solving a one-dimensional transient Fourier equation with the finite difference method (in the thickness direction).
• In the mold, by solving a three-dimensional steady state Laplace equation using the boundary element method.
Solver Setting Analysis Procedure Description
Number of Thickness Layers (10-16) Shell Specifies the number of virtual layers used to discretize the equations in the thickness direction.

Default: 15

Mold/Melt coupled iteration relaxation factor Shell/Solid The relaxation factor is a weighting factor that mathematically regulates the effect of the iterative solution update between the polymer and mold temperature fields.

Default: 0.8

• Increasing this relaxation factor may result in a faster convergence rate, but may introduce numerical instabilities that can trigger convergence problems.
• Reducing this relaxation factor may contribute to a more stable computation, but at a reduced convergence rate.
Maximum Number of Mold/Melt iterations (8 ~ 15) Shell/Solid

Limits the maximum number of iterations between the polymer and mold analyses. If the solver does not converge to a steady-state temperature within this limit, it assigns the temperature field of the last iteration to be the steady-state result.

Default: 8

Mold/Melt iteration relative tolerance (1.E-3 ~ 5.E-2) Shell/Solid Specifies the relative convergence tolerance of the local mold temperature between the current and previous iterative cycles.

Default: 0.01

Mold temperature iteration relaxation factor (0.2 - 0.8) Shell Active only for the Gauss iterative solver.

Governs the iterative update of the mold temperature field. Reducing this relaxation factor results in a more stable computation, but at a reduced convergence rate.

Default: 0.4

Maximum Number of Mold iterations (300 ~ 800) Shell

Limits the maximum number of internal iterations used by the algebraic equation solvers (Preconditioned Conjugate Gradient (PCG) or Gauss).

Default: 500

Mold iteration residual error tolerance (1.E-8 ~ 1.E-5) Shell Convergence criterion for the iterative algebraic equation solvers (PCG or Gauss). Iteration stops once the norm of the residual errors over the whole solution domain is less than the specified value.

Reducing this relaxation factor results in a more stable computation, but at a reduced convergence rate.

Default: 1E-6

Tubular-element Gauss integration points (4 or 6) Shell

Specifies the number of Gauss integration points contained in the line elements of the boundary element method used for cooling channel or runner analysis. To prevent instabilities, you can only use the values 4 or 6.

Increasing the number of Gauss points improves the solution accuracy, but requires more computational time.

Default: 4

Triangle-element Gauss integration points (4 or 6) Shell

Specifies the number of Gauss integration points contained in the triangle elements of the boundary element method used for parts.

Default: 4

Solver type Shell Specifies the type of algebraic equation matrix solver.

Default: Preconditioned Conjugate Gradient (PCG) solver. Reaches convergence for most problems.

The Gauss-Seidel iterative solver (Gauss) is an alternative solver, but is less likely to obtain a converged result.
Solver type Solid

Specifies the type of algebraic equation matrix solver.

Default: Algebraic Multigrid solver (AMG).

The AMG solver reaches convergence for most problems. It is faster and uses less storage than the Preconditioned AMG solver (PCG-AMG). The PCG-AMG solver might provide additional robustness, but at a significant storage and performance cost.

Transient mold temperature output interval (1~10) Solid Specifies the time step interval at which output for the mold temperature data is available. The output data is the transient temperature of the cavity wall for the Fill and Pack analysis. Reducing this value saves more transient data, but increases processing time.

Default: 5

Local profile resolution[X-Y Plot](1 ~ 3) Shell Specifies the resolution of the output data for the history of temperature in each local area. A higher resolution value saves more temporal data.

Default: 1

Analysis Method Solid Specifies the discretization method for the analysis.
• FVM: Finite volume method (cell-centered)
• FEM-Linear: Finite element method with linear elements (node-based)
• FEM-Quadratic: Finite element method with quadratic elements (node-based)

Default: FEM-Linear