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Huang C.-T.,Tamkang University | Tseng H.-C.,CoreTech System Moldex3D Co. | Chang R.-Y.,CoreTech System Moldex3D Co. | Hwang S.-J.,National Cheng Kung University
Annual Technical Conference - ANTEC, Conference Proceedings | Year: 2016

The lightweight technologies become the driving force for people in automotives and other developments in recent years. Among those technologies, using short and long fiber-reinforced thermoplastics (FRT) to replace some metal components can reduce the weight of an automotive significantly. However, the microstructures of fiber inside plastic matrix are too complicated to manage and control during the injection molding through the screw, the runner, the gate, and then into the cavity. In this study, we have integrated the screw plastification, to injection molding for fiber microstructures investigation. Specifically, we have paid our attention on fiber breakage prediction during screw plastification. Results show that fiber breakage is strongly dependent on screw design and operation. When the screw geometry changes, the fiber breakage can be higher even if the compression ratio is lower. Moreover, the fiber breakage phenomena for two types of fibers (glass fiber and carbon fiber) are also investigated. It shows that carbon fiber is easier to be broken. Also the carbon fiber length distribution has higher peak at the exit of the screw.


Tseng H.-C.,CoreTech System Moldex3D Co. | Chang R.-Y.,CoreTech System Moldex3D Co. | Hsu C.-H.,CoreTech System Moldex3D Co.
Composites Science and Technology | Year: 2017

Fiber reinforced polymer (FRP) composites offer exciting new possibilities for the green automotive industry, owing to their excellent mechanical properties, advantageous weight reduction and economical fuel consumption. In practice, accurately predicting fiber orientation is a critical issue in causing anisotropy in the mechanical properties of the FRP parts. Recently, an objective fiber orientation model, iARD-RPR (Improved Anisotropic Rotary Diffusion model combined with a Retarding Principal Rate model) proved significant in the field of fiber suspension rheology. Using state-of-the-art injection molding simulations, we therefore used the iARD-RPR model to explore the fiber orientation changes for various fiber components in regard to fiber length (short and long fibers) and fiber type (glass and carbon fibers). Under an extreme condition of higher fiber concentration and longer fiber lengths, a thicker core region and a narrow shell are always found in a typical orientation pattern of injection molded FRT parts. More importantly, these predicted orientation distributions provided to micromechanical material modeling computation of mechanical properties aid in the discussion on the reinforcing ability of short/long fibers and glass/carbon fibers based on the numerical simulation results. Comparisons with experimental data are also presented herein. © 2017 Elsevier Ltd


Hsu C.-C.,National Tsing Hua University | Huang C.-T.,Tamkang University | Chang R.-Y.,CoreTech System Moldex3D Co.
Proceedings of the 2016 IEEE 18th Electronics Packaging Technology Conference, EPTC 2016 | Year: 2016

According as high density packaging options such as multi-die staking or package stacking technologies are developed, the major mold process related quality concerns such as severe air void entrapment under the die. The accurate analysis of venting is important for realistic prediction of voids that may occur during chip encapsulation. This study reports a perspective investigation of computational modeling of air venting analysis with fluid-structure interaction (FSI) during microchip encapsulation process. The venting analysis is to calculate the pressure drop of the air that passes through the vent and include the effects of air pressure on the flow front. Through the integrated method with FSI method, we can predict precisely the FSI behavior with the dynamic mesh deformation technique simultaneously in accordance with venting analysis. This is different from previous study that only one way considered fixed geometry during venting analysis. Furthermore, a series of analyses are conducted to compare the experimental data to study the void risk. This result shows that the proposed modeling methodology is able to obtain better match of the experiment vs. simulation data than a traditional analysis. © 2016 IEEE.


Huang C.-T.,CoreTech System Moldex3D Co. | Tseng H.-C.,CoreTech System Moldex3D Co. | Chen M.-C.,CoreTech System Moldex3D Co. | Vlcek J.,Compuplast International Inc.
Annual Technical Conference - ANTEC, Conference Proceedings | Year: 2015

Due to the high demand of smart green, the lightweight technologies become the driving force for people in automotives and other developments in recent years. Among those technologies, using short and long fiber-reinforced thermoplastics (FRT) to replace some metal components can reduce the weight of an automotive significantly. However, the microstructures of fiber inside plastic matrix are too complicated to manage and control during the injection molding through the screw, the runner, the gate, and then into the cavity. In this study, we have integrated the screw plastification, to injection molding for fiber microstructures investigation. More specifically, paid most of our attention on fiber breakage prediction during screw plastification. Results show that fiber breakage is strongly dependent on screw design and operation. When the screw geometry changes, the fiber breakage can be higher even if the compression ratio is lower.


Chang W.-Y.,National Tsing Hua University | Huang C.-T.,CoreTech System Moldex3D Co. | Lee C.-K.,CoreTech System Moldex3D Co. | Chang R.-Y.,National Tsing Hua University
Annual Technical Conference - ANTEC, Conference Proceedings | Year: 2015

Lost wax process is widely used in metal casting to manufacture high precision products. However it covers lots of procedures, high precision quality is very difficult to obtain via conventional trial-and-error method. In this study, numerical method to simulate the wax pattern formation through injection molding in investment casting was proposed. To get better understanding, one hardware model is used to examine its shrinkage behavior numerically and experimentally. Through natural shrinkage and fixture constraint shrinkage study, the shrunk wax pattern dimensions and shrinkage percentage at various circular edges and location were measured. Simulation and experimental results are in good agreement. Specifically, the shrinkage difference between experiment and simulation is less than 1%. As the good control for the first step of wax pattern formation, it can further assist the shell formation and metal casting.


Lai J.-Y.,National Central University | Wang M.-H.,National Central University | Hsu C.-H.,CoreTech System Moldex3D Co. | Tsai Y.-C.,CoreTech System Moldex3D Co.
2016 International Conference on Applied System Innovation, IEEE ICASI 2016 | Year: 2016

Solid meshes are used in finite element analysis to represent the object geometry for simulation and analysis. Hexahedral and prism meshes are inherently more preferable to tetrahedral meshes, but are difficult to generate automatically. The purpose of this study was to develop an approach for meshing using feature recognition to decompose the target feature. Particularly, a boss recognition algorithm was proposed and the data for automatic meshing was established. A detailed description of the proposed algorithm was described, and several examples were presented to illustrate its feasibility. © 2016 IEEE.


Huang C.-T.,Tamkang University | Yang J.,CoreTech System Moldex3D Co Ltd. | Chang R.-Y.,CoreTech System Moldex3D Co Ltd.
AIP Conference Proceedings | Year: 2015

Co-Injection Molding and multi-cavity molding are very common processes for plastic manufacturing. These two systems are sometimes combined and applied to some structure products. The core penetration and flow balance control problems are very difficult to manage. The inside mechanism of co-injection multi-cavity system is not fully figured out yet. In this study, we have focused on the penetration phenomena of core-material in a co-injection multi-cavity molding. The dynamic penetration behavior of core is very sensitive to injection flow rate and skin/core ratio. The longest core penetration has been shown to change dramatically from one runner to the other. In addition, the core penetration behavior will display imbalance at the end of filling. The more core ratio it is, the longer core penetration flows through runner to cavity. However, due to the multi-cavity geometrical structure, the balance of the core penetration for multi-cavity is still challenging. Finally, the simulation is validated with some literature. The results showed that both simulation and experiment are in a good agreement in trend. © 2015 AIP Publishing LLC.


Tseng H.-C.,CoreTech System Moldex3D Co. | Tseng H.-C.,National Tsing Hua University | Chang R.-Y.,National Tsing Hua University | Hsu C.-H.,CoreTech System Moldex3D Co.
Journal of Rheology | Year: 2013

The standard Folgar-Tucker (FT) orientation equation is a useful method for theoretically determining isotropic fiber orientation in concentrated suspensions. However, when quantitatively compared with related experimental observations, this equation demonstrates an over-prediction inaccuracy. Recently, the Phelps-Tucker anisotropic rotary diffusion (ARD) model has shown an ability to handle primary anisotropic fiber orientation. Nevertheless, the ARD tensor depending upon Hand's tensor is difficult to apply in general, because numerous parameters themselves are so sensitive as to affect the stability of any numerical results. To address these critical problems in predicting fiber orientation, this study proposes an improved ARD tensor combined with a new retardant principal rate (iARD-RPR) model. The RPR model is a coaxial correction of the orientation tensor for the FT equation. In addition, the iARD tensor, consisting of an identity tensor and a dimensionless fiber-rotary-resistance tensor, is more concise with two available parameters. As a validation, the iARD-RPR model nicely fits the orientation tensor components measured in transient simple shear flows. Of particular importance is the good agreement between the predictive fiber orientation distribution and the practical core-shell structure for the center-gated disk of injection molding of fiber-reinforced thermoplastics. © 2013 The Society of Rheology.


Huang C.-T.,CoreTech System Moldex3D Co. | Tseng H.-C.,CoreTech System Moldex3D Co. | Vlcek J.,Compuplast International Inc. | Chang R.-Y.,CoreTech System Moldex3D Co.
IOP Conference Series: Materials Science and Engineering | Year: 2015

Due to the high demand of smart green, the lightweight technologies have become the driving force for the development of automotives and other industries in recent years. Among those technologies, using short and long fiber-reinforced plastics (FRP) to replace some metal components can reduce the weight of an automotive significantly. However, the microstructures of fibers inside plastic matrix are too complicated to manage and control during the injection molding through the screw, the runner, the gate, and then into the cavity. This study focuses on the fiber breakage phenomena during the screw plastification. Results show that fiber breakage is strongly dependent on screw design and operation. When the screw geometry changes, the fiber breakage could be larger even with lower compression ratio.


Hsu C.-C.,National Tsing Hua University | Wang T.-C.,CoreTech System Moldex3D Co. | Chen Y.-C.,CoreTech System Moldex3D Co. | Lin Y.-K.,CoreTech System Moldex3D Co.
Proceedings - Electronic Components and Technology Conference | Year: 2014

This paper reports a perspective investigation of computational modeling of fluid-structure interaction (FSI) in molded integrated-circuit(IC) packaging. The investigation is carried out through two aspects, respectively on interaction between the fluid and structure in the encapsulation process and appropriate methodology for modeling. We present a novel and integrated method to predict the FSI during the encapsulation process. This method not only provides more accurate melt front and pressure result but also predict precisely the FSI behavior through the dynamic mesh deformation technique simultaneously in accordance with continually deformed geometry (two way FSI). This is different from previous study that only one way considered fixed geometry (one way FSI) during encapsulation. Moreover, the experimental data for single- and stacked-chip were compared with the simulation results for two way FSI implementation to verify flow front advancement. From a real paddle shift case study, the result indicates that the deflection prediction is well predicted and could predict void formation well when it considers two way FSI effect. It is expected that this paper could clarify relevant issues in prediction of FSI in IC packaging and induce more considerations for modeling FSI using two way FSI multiphase flow method. © 2014 IEEE.

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