As a natural progression resulting from the development of microcellular molding simulations for 3D models, and the introduction of the bubble nucleation model, the workflow for dual domain and midplane models has been improved, to ensure consistency for all mesh types.
You will notice several changes to the
Process Settings Wizard, while setting up the analysis. The first change is the
Velocity/pressure switch-over setting, which is found on the
Fill, or
Fill+Pack page. There are two new options:
- [By % weight reduction] at
- This option enables you to specify the weight reduction you are aiming for. If you would like the part to be 5% lighter than a conventional part, you would enter 5 here. The part will fill until the weight is 5% lighter than a conventional injection molded part, then switch to pressure control to allow bubble growth.
- [By part weight (excluding runners)] at
- This option enables you to enter a specific weight of material that you would like injected, before switching from velocity to pressure control.
The Microcellular Injection Molding Settings page of the Process Settings Wizard has undergone a dramatic change to simplify the analysis setup. Select the foaming gas: nitrogen, carbon dioxide, or other, enter the initial gas amount as a concentration by weight %, or gas saturation pressure, then select the bubble nucleation model; constant nucleation density (this is the legacy model), or the Fitted Classical Nucleation Model (new with this release). You no longer need to input an initial bubble radius, and the number of cells per volume is only required if you select the constant nucleation density model.
Finally, there are some new results to help you determine the feasibility of your design:
-
Bubble number density
- The Bubble number density result shows the density of bubbles through the part as the analysis progresses. Ideally, the bubble number density should be fairly uniform throughout the core regions of the part. An area with very few bubbles may indicate that there is insufficient foaming gas present, or that the part froze early before the pressure decreased sufficiently to allow bubble growth. This result is only available if the Number of profiled results specified in the solver parameters is greater than zero.
-
Bubble number density final
- The Bubble number density, final result shows the density of bubbles through the part at the end of the analysis. Ideally, the bubble number density should be fairly uniform throughout the core regions of the part. An area with very few bubbles may indicate that there is insufficient foaming gas present, or that the part froze early before the pressure decreased sufficiently to allow bubble growth.
-
Shear Modulus (Microcellular)
- The Shear modulus, sometimes called the rigidity modulus, refers to the change produced by a tangential stress, and provides a measure of how "stiff" the material is.