Crystallization analysis
For injection molding applications using semi-crystalline thermoplastics materials, accounting for the flow-induced crystallization and morphological changes of these materials can improve the prediction accuracy of cavity pressure decay and the mechanical properties of the molded parts, and subsequent shrinkage and warpage predictions.
Crystallization analysis accounts for the effect of flow on crystallization of the material by relating excess free energy and flow-induced orientation to crystallization kinetics [1]. In turn, the crystallization of the material influences the flow analysis, including changes in the modeling of viscosity, pvT, solidification, the inclusion of latent heat in the energy equation, and the orientation effect on shrinkage.
The following table shows the available analysis technologies for a Crystallization analysis.
where
indicates a Midplane mesh
indicates a Dual Domain mesh
Supported molding processes for Crystallization analyses
| Molding Process | Analysis Sequence | Mesh Type |
|---|---|---|
| Thermoplastics Injection Molding | Fill+Pack | |
| Thermoplastics Injection-Compression Molding | Fill+Pack | |
Crystallization analysis produces the following results in addition to the general flow analysis results:
- Crystallization: Crystalline orientation factor [2]
- Crystallization: Relative crystallinity
- Crystallization: Average relative crystallinity
- Crystallization: Mechanical properties E11 [2]
- Crystallization: Mechanical properties E22 [2]
- Crystallization: Final average crystal size
- Crystallization: Final relative crystallinity
[1] This Flow-Induced Crystallization model is the subject of a United States Patent application (R. Zheng, P.K. Kennedy and R.I. Tanner), and Autodesk holds an exclusive license for use of this model.
[2] This result is not available when the selected material is fiber-filled and fiber orientation analysis is performed; the corresponding fiber orientation analysis result dominates.
The effect on the predicted mechanical properties (including orientation) then influences subsequent shrinkage (and therefore, warpage) predictions.