scholarly journals Molten Plastic Flow Simulation in the Injection Molding Process

1990 ◽  
Vol 10 (1Supplement) ◽  
pp. 97-98
Author(s):  
Akira MIZUKAMI ◽  
Keita MAEDA
Keyword(s):  
Injection Molding ◽  
Plastic Flow ◽  
Flow Simulation ◽  
Injection Molding Process ◽  
Molding Process

scholarly journals Estimation of Injection Molding Process for a Thin Fresnel lens By Plastic Flow Simulation

2019 ◽  
Vol 8 (10) ◽  
pp. 3276-3282
Keyword(s):  
Injection Molding ◽  
Plastic Flow ◽  
Flow Analysis ◽  
Flow Simulation ◽  
Fresnel Lens ◽  
Injection Molding Process ◽  
Molding Process ◽  
Manufacturing Defects ◽  
Simulation Results ◽  
Plastic Parts

This paper is based on the plastic flow simulation of a thin Fresnel lens to estimate the injection molding process. Nowadays Fresnel lenses are made of transparent plastics materials instead of silica-based glass to reduce handling and processing cost. For mass manufacturing of plastic parts, the injection molding process is best suited. Thus in this study plastic flow analysis of a thin Fresnel lens is carried for the evaluation of injection molding process. Plastic flow analysis helps in estimating how molten plastic will flow during the process Plastic flow analysis is also very helpful in evaluating the manufacturing defects such as air traps and weld lines without real-time experimentation. The simulation results evaluate the values of the parameters such as fill time, filing pressure, pack pressure, etc. Also, the manufacturing defects observed by the simulation results are reasonable and met the design requirement.

GRANULAR FLOW SIMULATION FOR METAL INJECTION MOLDING PROCESS

1993 ◽  
Vol 07 (09n10) ◽  
pp. 2047-2056 ◽  
Author(s):  
TAKASHI IWAI ◽  
TATSUHIKO AIZAWA ◽  
JUNJI KIHARA
Keyword(s):  
Injection Molding ◽  
Distinct Element ◽  
Constitutive Relations ◽  
Flow Simulation ◽  
Metal Injection Molding ◽  
Injection Molding Process ◽  
Molding Process ◽  
Polymer Medium ◽  
Powder Particles ◽  
Complex Fluid

Metal Injection Molding treats the complex fluid which consists of thermoplastic tic polymer medium and dense metallic powder suspensions to improve flowability and formability. To understand its fundamental mechanical behavior, it is important to consider powder structures and mechanics precisely. For the analysis of this process, a new granular model is proposed, which is based on the Distinct. Element Method. Each element in this method is constituted by combining a metal powder with a binder (polymer) shell surrounding it. Both elasticity and viscosity for powder particles and binders are only considered in this mixture model as the constitutive relations. Several numerical results have demonstrated the effectiveness and validity of our developed granular modeling to deal with the various phenomena appearing in MIM process.

scholarly journals An Assessment of Thermoset Injection Molding for Thin-Walled Conformal Encapsulation of Board-Level Electronic Packages

2019 ◽  
Vol 3 (1) ◽  
pp. 18 ◽  
Author(s):  
Romit Kulkarni ◽  
Peter Wappler ◽  
Mahdi Soltani ◽  
Mehmet Haybat ◽  
Thomas Guenther ◽  
...  
Keyword(s):  
Injection Molding ◽  
Manufacturing Industry ◽  
Mechanical Stability ◽  
Flow Simulation ◽  
Dust Particles ◽  
Injection Molding Process ◽  
Market Demand ◽  
Molding Process ◽  
Thin Walled ◽  
Board Level

An ever-growing market demand for board (second) level packages (e.g., embedded systems, system-on-a-chip, etc.) poses newer challenges for its manufacturing industry in terms of competitive pricing, higher reliability, and overall dimensions. Such packages are encapsulated for various reasons including thermal management, protection from environmental conditions and dust particles, and enhancing the mechanical stability. In the due course of reducing overall sizes and material saving, an encapsulation as thin as possible imposes its own significance. Such a thin-walled conformal encapsulation serves as an added advantage by reducing the thermo-mechanical stresses occurring due to thermal-cyclic loading, compared to block-sized or thicker encapsulations. This paper assesses the encapsulation process of a board-level package by means of thermoset injection molding. Various aspects reviewed in this paper include the conception of a demonstrator, investigation of the flow simulation of the injection molding process, execution of molding trials with different encapsulation thicknesses, and characterization of the packages. The process shows a high dependence on the substrate properties, injection molding process parameters, device mounting tolerances, and device geometry tolerances. Nevertheless, the thermoset injection molding process is suitable for the encapsulation of board-level packages limiting itself only with respect to the thickness of the encapsulation material, which depends on other external aforementioned factors.

Injection Molding of Rubber Compounds: Experimentation and Simulation

1991 ◽  
Vol 64 (2) ◽  
pp. 296-324 ◽  
Author(s):  
J. S. Deng ◽  
A. I. Isayev
Keyword(s):  
Experimental Data ◽  
Injection Molding ◽  
Induction Time ◽  
Flow Simulation ◽  
Injection Molding Process ◽  
Model Parameters ◽  
Large Sample Size ◽  
Molding Process ◽  
Rubber Compounds ◽  
Pressure Development

Abstract Results of experimental and theoretical studies of injection molding of rubber compounds have been reported. Characterizations on the rheological properties and the vulcanization kinetics of rubber compounds were carried out by means of MPT and DSC, respectively. The models were employed to fit these experimental data. An attempt has been made in extending the proposed empirical kinetic model based on DSC data to similar curing data obtained by means of the MDR technique. The heat-transfer effect due to the large sample size used in MDR measurements has been found to have a small effect on the kinetic data. Due to the different principle of state-of-cure measurements in MDR and DSC, the model parameters of curing kinetics have been found to be different in these measurements. A two-dimensional flow simulation of generalized Newtonian fluids based on both finite-difference and finite-element methods has been performed. The pressure development at various positions along the flow path during the filling stage of the molds was obtained experimentally for various injection speeds. The predicted results on pressure development during cavity filling showed qualitative agreement with the experimental data. Possible reasons for the observed discrepancy in pressure traces are: neglect of local extra pressure losses (in the juncture sections), compressibility of rubber compounds, leakage (back-flow) of material during injection, and voids formation in the injection chamber. The study on the vulcanization behavior of rubber compounds during injection molding process has also been done. The proposed empirical kinetic and induction time models were able to satisfactorily predict the cure levels of molded rubber products. At the same time, the results predicted by employing nth order kinetics were found to be unsatisfactory. The contribution of nonisothermal induction time in calculating cure levels of the molded rubber products was found to be significant. The mechanical properties and anisotropy have been investigated for two rubber compounds. It is suggested that there exists a mold temperature at which the properties and cycle times are optimal, and the filler type shows a significant effect on the tensile modulus. The rubber moldings were found to be highly anisotropic in mechanical behaviors. The anisotropy could be reduced significantly at high injection speed due to the faster stress-relaxation process.

Filling Behavior of Polymer Material into Sub-^|^mu;m Structure in Injection Molding Process

2013 ◽  
Vol 133 (4) ◽  
pp. 105-111
Author(s):  
Chisato Yoshimura ◽  
Hiroyuki Hosokawa ◽  
Koji Shimojima ◽  
Fumihiro Itoigawa
Keyword(s):  
Injection Molding ◽  
Polymer Material ◽  
Injection Molding Process ◽  
Molding Process

scholarly journals Study on External Gas-Assisted Mold Temperature Control with the Assistance of a Flow Focusing Device in the Injection Molding Process

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 965 ◽  
Author(s):  
Nguyen Truong Giang ◽  
Pham Son Minh ◽  
Tran Anh Son ◽  
Tran Minh The Uyen ◽  
Thanh-Hai Nguyen ◽  
...  
Keyword(s):  
Injection Molding ◽  
Temperature Control ◽  
Mold Temperature ◽  
Injection Molding Process ◽  
Melt Flow ◽  
Flow Focusing ◽  
Molding Process ◽  
Heating Efficiency ◽  
Flow Length ◽  
Insert Plate

In the injection molding field, the flow of plastic material is one of the most important issues, especially regarding the ability of melted plastic to fill the thin walls of products. To improve the melt flow length, a high mold temperature was applied with pre-heating of the cavity surface. In this paper, we present our research on the injection molding process with pre-heating by external gas-assisted mold temperature control. After this, we observed an improvement in the melt flow length into thin-walled products due to the high mold temperature during the filling step. In addition, to develop the heating efficiency, a flow focusing device (FFD) was applied and verified. The simulations and experiments were carried out within an air temperature of 400 °C and heating time of 20 s to investigate a flow focusing device to assist with external gas-assisted mold temperature control (Ex-GMTC), with the application of various FFD types for the temperature distribution of the insert plate. The heating process was applied for a simple insert model with dimensions of 50 mm × 50 mm × 2 mm, in order to verify the influence of the FFD geometry on the heating result. After that, Ex-GMTC with the assistance of FFD was carried out for a mold-reading process, and the FFD influence was estimated by the mold heating result and the improvement of the melt flow length using acrylonitrile butadiene styrene (ABS). The results show that the air sprue gap (h) significantly affects the temperature of the insert and an air sprue gap of 3 mm gives the best heating rate, with the highest temperature being 321.2 °C. Likewise, the actual results show that the height of the flow focusing device (V) also influences the temperature of the insert plate and that a 5 mm high FFD gives the best results with a maximum temperature of 332.3 °C. Moreover, the heating efficiency when using FFD is always higher than without FFD. After examining the effect of FFD, its application was considered, in order to improve the melt flow length in injection molding, which increased from 38.6 to 170 mm, while the balance of the melt filling was also clearly improved.

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