TIPS for asymmetric fill pattern of 3D mesh

You may occasionally see the asymmetric fill pattern in symmetrical shape part. This type of issue is usually caused by mesh quality or size.

If you face asymmetric fill pattern issue, please try following things.

 

TIPS1: Refine the mesh around the gate

This type of asymmetric filling pattern is often caused by condition of connection between beam and 3d mesh.

If you look at each gate, numbers of connected 3D mesh are different on each gate.

 

You may improve accuracy of fill pattern after making a much finer Dual Domain mesh around the gates and then create 3D mesh from it as below.

 

On this example model, following improvement was observed after using fine mesh around the all gates.

 

 

TIPS2 : Use 3D runner system

You may see improvement, if you use 3D runner system. Following guideline is useful for 3D mesh runner system.

 

1. Use fine 3D mesh for runner system and around the gates.
2. 8 or more layers of elements through the thickness.

 

Following improvement was observed on this example model.

 

 

Note:

You can find following related information for TIPS1 on the “Accuracy Improvements Implemented in the 3D Flow Solver” document ( asmi2013_3d_flow_accuracy_improvements_en.pdf ).

If you have a subscription contract, you can download this document from the subscription center http://subscription.autodesk.com/.

 

The software provides a capability for direct injection into the part for quick scoping and sensitivity analyses. However, when accurate results are desired the runner system should be included. The quality of the tetrahedral mesh around the gate is usually critical to accurately model effects such as the high local pressure gradients and viscous heating, jetting and gate freezing during pack. Preferably reduce the local size of the initial surface elements so that there are at least four tetrahedral surface facets across the gate diameter. (Even that may not be enough, for example if a cutting plane shows a higher temperature near the runner surface due to viscous heating.)

Comments

[Jim McGuire]

I highly recommend the document cited in this post, as it is very well written, and highly informative. I'm also very encouraged by the recent improvements in the solver!

That said, the bigger issue remains that on non-symmetrical parts, one certainly gets inaccurate filling results at times, but may not know it, as the results are not as intuitive. How can we tell when this occurs, and how can we overcome it?

[Kazuhiko Ito]

Hello,
Thank you for your comment.
I understand your point. However, that is most difficult to know. The current approach is to improve the quality of the model (mesh, material data and process settings) before you get inaccurate result.

If the fill pattern is obviously inaccurate, I recommend to contact support with the model for specific issue.

Best regards,
Kazuhiko