Melt Front Time: 99%
The microcellular injection molding (MuCell®) process can mass-produce parts with complex geometries and excellent dimensional stability. It is used in various applications, such as automobiles and electronic/electrical, construction, and outdoor products. In this process, a supercritical fluid, usually nitrogen or carbon dioxide, is mixed with a polymer melt to create a single-phase polymer/gas solution. This is then injected into the mold cavity, where bubbles form within the product.
Some of the benefits of this technology include lower injection pressures, lower temperatures, shorter cycle times, less energy, and less material. Despite these, the addition of supercritical fluid brings the complexity of material morphology, flow behavior, and product surface quality. These hamper the development and broad acceptance of the process.
Moldex3D MuCell® employs the fundamental physics of bubble nucleation and growth to model this complex process realistically. It lets manufacturers and design engineers visualize a microcellular injection molding process and understand its complex filling behavior and foaming mechanism. In addition, it reveals the mystery of microcellular injection molding while providing design validation, time-to-market optimization, and development cost reduction.
Plastics (i.e., polymeric) fluids are often called viscoelastic fluids because they have viscous and elastic properties. The viscoelastic effect depends on different temperatures and shear rates. During the filling stage, the flow field varies severely, and the viscous property of the polymer determines flow behavior.
Moldex3D Viscoelasticity predicts the frozen flow-induced stress near the mold surface due to fast solidification caused by high cooling rates during filling. As solidification develops during the packing stage, the high temperature caused by solidification within the mold helps release the stress. However, flow-induced stress may develop in the central area near the gate due to additional shear flow during packing. Cooling efficiencies at different cooling processes also affect the stresses’ relaxation. Moldex3D Viscoelasticity captures and predicts all these conditions during the injection molding process.
This software product describes anisotropic molecular orientation based on the maximum principal stress (i.e., maximum normal stress) of flow-induced residual stress. By examining molecular orientation information, maximum normal stress, and maximum shear stress, you can determine if the final product is acceptable. In addition, you can further modify the mold design and process conditions. The results obtained from Moldex3D Viscoelasticity can even be applied to predict optical properties and considered in warpage analysis.
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