Mold Filling using a non-Newtonian fluid

Parent Category: Polymer Industry

The filling of a mold form with liquid polymer is a complicated fluid mechanical problem. The exact computation of the process can greatly help to understand deficiencies of the finished mold such as unfilled cavities, structural weaknesses e.g. due to inappropriate cooling down, air traps or misplaced or otherwise corrupted weld lines.

NOGRID points (a meshless CFD simulation software) enables a fast computation of the free surface at the flow front in conjunction with the ability to incorporate complicated material properties and boundary conditions allow an in-depth analysis of this process.

CFD meshless Flow Simulation filling mold form

Figure 1: Filling a micro channel using the Carreau model

The symmetric model shown above is computed without the use of symmetry. Nevertheless the two flow fronts meet exactly in the middle of the mold form. The viscosity of the polystyrene is determined by the Carreau model (i.e. it depends on the shear rate). The simulation can be used to study the flow at the entrance into the micro channel section and to understand the forming of the weld line at the center.