An Investigation into the Influencing Factors for Polymer Melt at the Filling Stage in Micro Injection Molding

2013 ◽  
Vol 562-565 ◽  
pp. 1380-1386
Author(s):  
Jian Zhuang ◽  
Da Ming Wu ◽  
Ya Jun Zhang ◽  
Lin Wang ◽  
Xiong Wei Wang ◽  
...  
Keyword(s):  
Injection Molding ◽  
Influencing Factors ◽  
Polymer Melt ◽  
Theoretical Models ◽  
Injection Molding Process ◽  
Melt Flow ◽  
Molding Process ◽  
Micro Injection Molding ◽  
Filling Stage ◽  
Conventional Injection Molding

The flow behaviors for polymer melt at the filling stage in micro injection molding are different from those in conventional injection molding due to the miniaturization of plastic parts. This paper focuses on the study of the effects of three main influencing factors, including the microscale viscosity and wall slip, on melt filling flow in microscale neglected those in conventional injection molding process. The theoretical models and the interrelation of these factors in microscale channels were constructed by means of the model correction method. Then, the micro melt flow behaviors were investigated with comparisons of the available experimental data. The results indicate that the dimensions affect the shear rates and viscous dissipation, which in turn affects the apparent viscosity. Finally, the conclusion is that the melt flow behaviors in microchannels are different from those in macrochannels owing to these significant influencing factors.

scholarly journals Evaluation by nanoindentation of technological products manufactured by pulse injection molding process

2018 ◽  
Vol 145 ◽  
pp. 02006
Author(s):  
Margarita Natova ◽  
Ivan Ivanov ◽  
Sabina Cherneva ◽  
Maria Datcheva ◽  
Roumen Iankov
Keyword(s):  
Injection Molding ◽  
Polymer Melt ◽  
Injection Molding Process ◽  
Melt Flow ◽  
Molding Process ◽  
Polymer Injection ◽  
Pulse Injection ◽  
Molding Flow ◽  
Different Parts ◽  
Technological Products

During conventional polymer injection molding, flow- and weld lines can arise at the molded parts caused by disturbed polymer melt flow when it crosses different parts of the equipment. Such processed plastic goods have discrete zones of inhomogeneities of very small dimensions. In order to stabilize the melt flow and to equalize dimensions of such defective products, an approach for pulse injection molding is applied during production of polymer packagings. Testing methods used for evaluation of macromechanical performance of processed polymer products are not readily applicable to estimate the changes in visual surface obtained during pulse injecting. To overcome this testing inconvenience the performance of processed packagings is evaluated by nanoindentation. Using this method, a quantitative assessment of the polymer properties is obtained from different parts of technological products.

Study of polymer melt flow in sequential injection molding process

AIChE Journal ◽  
1996 ◽  
Vol 42 (6) ◽  
pp. 1706-1714 ◽  
Author(s):  
S. C. Chen ◽  
N. T. Chen ◽  
K. S. Hsu ◽  
K. F. Hsu
Keyword(s):  
Injection Molding ◽  
Polymer Melt ◽  
Injection Molding Process ◽  
Sequential Injection ◽  
Melt Flow ◽  
Molding Process

Computational Study of the Effect of Governing Parameters on a Polymer Injection Molding Process for Single-Cavity and Multicavity Mold Systems

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
M. Tutar ◽  
A. Karakus
Keyword(s):  
Injection Molding ◽  
Mold Insert ◽  
Polymer Melt ◽  
Injection Molding Process ◽  
Melt Flow ◽  
Flow Conditions ◽  
Molding Process ◽  
Polymer Injection ◽  
Solution Approach ◽  
Polymer Injection Molding

In the present study a more complete numerical solution approach using parallel computing technology is provided for the three-dimensional modeling of mold insert polymer injection molding process by considering the effects of phase-change and compressibility for non-Newtonian fluid flow conditions. A volume of fluid (VOF) method coupled with a finite volume approach is used to simulate the mold-filling stage of the injection molding process. The variations in viscosity and density in the polymer melt flow are successfully resolved in the present VOF method to more accurately represent the rheological behavior of the polymer melt flow during the mold filling. A comprehensive high-resolution differencing scheme (compressive interface capturing scheme for arbitrary meshes or CICSAM) is successfully utilized to capture moving interfaces and the pressure-implicit with splitting operators pressure-velocity coupling algorithm is employed to enable a higher degree of approximate relation between corrections for pressure and velocity. The capabilities of the proposed numerical methodology in modeling real molding flow conditions are verified through quantitative and qualitative comparisons with other simulation programs and the data obtained from the experimental study conducted. The present numerical results are also compared with each other for a polypropylene female threaded adaptor pipe fitting model with a metallic insert for varying governing process conditions/parameters to assess the modeling constraints and enhancements of the present numerical procedure and the effects of these conditions to optimize the polymer melt flow for mold insert polymer injection molding process. The numerical results suggest that the present numerical solution approach can be used with a confidence for further studies of optimization of design of mold insert polymer injection molding processes.

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.

scholarly journals Vacuum Venting Enhances the Replication of Nano/Microfeatures in Micro-Injection Molding Process

2016 ◽  
Vol 4 (2) ◽  
Author(s):  
Seong Ying Choi ◽  
Nan Zhang ◽  
J. P. Toner ◽  
G. Dunne ◽  
Michael D. Gilchrist
Keyword(s):  
Injection Molding ◽  
Quantitative Study ◽  
Vacuum Pressure ◽  
Injection Molding Process ◽  
Anodized Aluminum ◽  
Molding Process ◽  
Micro Injection Molding ◽  
Sample Shape ◽  
Final Sample ◽  
Qualitative And Quantitative Study

Vacuum venting is a method proposed to improve feature replication in microparts that are fabricated using micro-injection molding (MIM). A qualitative and quantitative study has been carried out to investigate the effect of vacuum venting on the nano/microfeature replication in MIM. Anodized aluminum oxide (AAO) containing nanofeatures and a bulk metallic glass (BMG) tool mold containing microfeatures were used as mold inserts. The effect of vacuum pressure at constant vacuum time, and of vacuum time at constant vacuum pressure on the replication of these features is investigated. It is found that vacuum venting qualitatively enhances the nanoscale feature definition as well as increases the area of feature replication. In the quantitative study, higher aspect ratio (AR) features can be replicated more effectively using vacuum venting. Increasing both vacuum pressure and vacuum time are found to improve the depth of replication, with the vacuum pressure having more influence. Feature orientation and final sample shape could affect the absolute depth of replication of a particular feature within the sample.

Evaluation of a Piezoelectric Energy Extraction Device for Cavity Pressure Sensing in Injection Molding

2003 ◽  
Author(s):  
Charles B. Theurer ◽  
Li Zhang ◽  
David Kazmer ◽  
Robert X. Gao
Keyword(s):  
Injection Molding ◽  
Mechanical Strain ◽  
Piezoelectric Element ◽  
Polymer Melt ◽  
High Energy ◽  
Injection Molding Process ◽  
Molding Process ◽  
Transient Model ◽  
Piezoelectric Energy ◽  
Wide Range

This paper presents the design, analysis, and validation of a self-energized piezoelectric pressure sensor that extracts energy from the pressure differential of the polymer melt during the injection molding process. To enable a self-energized sensor design, an analytical study has been conducted to establish a quantitative relationship between the polymer melt pressure and the energy that can be extracted through a piezoelectric converter. Temperature and pressure are monitored during an injection molding cycle and the performance of the piezoelectric element is evaluated with respect to a mechanically static, electrically transient model. In addition to corroboration of the proposed model, valuable statistical information about the working temperature in the prototype sensor will prove very useful in the package design of molding cavity sensors. A linear model examining the energy conversion mechanism due to interactions between the mechanical strain and the electric field developed within the piezoelectric device is established. This model is compared to the functional prototype design to evaluate the relevance of the assumptions and accuracy. The presented design enables a new generation of self-energized sensors that can be employed for the condition monitoring of a wide range of high-energy manufacturing processes.

scholarly journals Experimental Validation of Injection Molding Simulations of 3D Microparts and Microstructured Components Using Virtual Design of Experiments and Multi-Scale Modeling

Micromachines ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 614 ◽  
Author(s):  
Dario Loaldi ◽  
Francesco Regi ◽  
Federico Baruffi ◽  
Matteo Calaon ◽  
Danilo Quagliotti ◽  
...  
Keyword(s):  
Injection Molding ◽  
Process Simulation ◽  
Current Work ◽  
Injection Molding Process ◽  
Process Conditions ◽  
Virtual Design ◽  
Molding Process ◽  
Micro Injection Molding ◽  
Multi Scale ◽  
Filling Time

The increasing demand for micro-injection molding process technology and the corresponding micro-molded products have materialized in the need for models and simulation capabilities for the establishment of a digital twin of the manufacturing process. The opportunities enabled by the correct process simulation include the possibility of forecasting the part quality and finding optimal process conditions for a given product. The present work displays further use of micro-injection molding process simulation for the prediction of feature dimensions and its optimization and microfeature replication behavior due to geometrical boundary effects. The current work focused on the micro-injection molding of three-dimensional microparts and of single components featuring microstructures. First, two virtual a studies were performed to predict the outer diameter of a micro-ring within an accuracy of 10 µm and the flash formation on a micro-component with mass a 0.1 mg. In the second part of the study, the influence of microstructure orientation on the filling time of a microcavity design section was investigated for a component featuring micro grooves with a 15 µm nominal height. Multiscale meshing was employed to model the replication of microfeatures in a range of 17–346 µm in a Fresnel lens product, allowing the prediction of the replication behavior of a microfeature at 91% accuracy. The simulations were performed using 3D modeling and generalized Navier–Stokes equations using a single multi-scale simulation approach. The current work shows the current potential and limitations in the use of micro-injection molding process simulations for the optimization of micro 3D-part and microstructured components.

Study on Improving the Life of Stereolithography Injection Mold

2012 ◽  
Vol 468-471 ◽  
pp. 1013-1016 ◽  
Author(s):  
Hua Qing Lai
Keyword(s):  
Injection Molding ◽  
Injection Molding Process ◽  
Injection Mold ◽  
Molding Process ◽  
Molded Parts ◽  
Injection Molded ◽  
Plastic Parts ◽  
Assembly Operations ◽  
Conventional Injection Molding ◽  
Shape And Size

Molding is one of the most versatile and important processes for manufacturing complex plastic parts. It is a method of fabricating plastic parts by utilizing a mold or cavity that has a shape and size similar to the part being produced. Molten polymer is injected into the cavity, resulting in the desired part upon solidification. The injection-molded parts typically have excellent dimensional tolerance and require almost no finishing and assembly operations. But new variations and emerging innovations of conventional injection molding have been continuously developed to offer special features and benefits that cannot be accomplished by the conventional injection molding process. This study aims to improving the life of stereolithography injection mold.

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