| Summary: | 碩士 === 國立中央大學 === 機械工程學系 === 107 === In finite element analysis, mesh generation is an important technique, which
directly affects the accuracy and computational efficiency of the simulation.
Using BLM (Boundary layer meshes) automatically is fast and easy in Moldex3D,
but the mesh quality is not excellent. If using Hexahedron or Prism mesh can
greatly improve mesh quality but consuming more time. Therefore, this study
generate three kinds of meshes, Prism + Hexa mesh, Mostly Hexa mesh and BLM
mesh. To verify the accuracy of model, we compared the results of simulation
with experimental melt front and optical retardation. The results of the study
shows that the Mostly Hexa mesh can bring the correct molding simulation results.
The results of molding simulation of Prism+ Hexa mesh are not so correct. And
the results of molding simulation of BLM mesh are incorrect. Then, through the
convergence analysis, we generate the different size for Mostly Hexa mesh. By
comparing the simulation with the experiment, we found that the mesh size of
0.04 mm can bring the through correct molding simulation results.
In order to improve the shape accuracy of optical lenses, industry often use
the total volume compensation method to optimize the warpage. However, due to
the unequal concentration of the product, it is difficult to meet the requirements
of all parts of the product. In this research, we use 3D Volume shrinkage
compensation method (3DVSCM) for cavity compensation. In conclusion, using
3DVSCM obviously improves the outer diameter and center thickness of the
optical lens.
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