Numerical Simulation of the LCP Hele-Shaw Flow Based on the Injection Molding Process

2014 ◽  
Vol 609-610 ◽  
pp. 681-686
Author(s):  
Chun Bo Liu ◽  
Jian Ye Sun
Keyword(s):  
Pressure Field ◽  
Velocity Fields ◽  
Injection Molding Process ◽  
Flow Front ◽  
Square Cavity ◽  
Molding Process ◽  
Center Layer ◽  
Application Range ◽  
Injection Process ◽  
Simulation Results

In order to broaden the application range of LCP, the simulation of the LCP Hele-Shaw flow in the square cavity was conducted. The temperature of the cavity was constant 300°C. In the simulation the Leslie-Ericksen and TIF theories were used. With this simulation results, we can predict the position of the flow front at any time during the whole injection process and grasp the change of the pressure field and the velocity field. The change of the pressure and the velocity fields were very slow, there was no distortion point in the whole flow field. In the layer near the wall, the directors arranged evenly according to the direction of the flow and in the center layer it was decided by the shear rate in the X-Y plane.

Study of the Influence of Surface Mold Deposits on the Demolding Stage of the Injection Molding Process of Thermoplastics

2006 ◽  
Author(s):  
Mikae¨l Chailly ◽  
Vincent Gilbert ◽  
Jean-Yves Charmeau ◽  
Yves Bereaux
Keyword(s):  
Amorphous Polymer ◽  
Infrared Camera ◽  
Acrylonitrile Butadiene Styrene ◽  
Injection Molding Process ◽  
Mold Surface ◽  
Molding Process ◽  
Injection Process ◽  
Molded Parts ◽  
Styrene Acrylonitrile ◽  
Thermal Influence

Due to increasing expectings from the market, the aspect of molded parts has to be improved. Some of the defects observed such as scratches on these parts is related to the demolding stage. To limit this, we investigated the influence on demolding forces using various surface deposits on the mold surface, mainly PVD and PACVD deposits : Chromium nitrium (CrN), Titane nitrium (TiN), Diamond like Carbon (DLC), glassy deposit (SiOx), Chromium and polished steel on an cube-shaped insert in an instrumented mold (with force sensors). Injection campaign was led on three polymers which differ in terms of nature : an amorphous polymer (polycarbonate), a semi-crystalline one (polybutylene terephatalate) and one mix of copolymers (styrene acrylonitrile/ acrylonitrile butadiene styrene). We studied the evolution of these forces through the demolding stage. This allowed us to evaluate the work energy necessary to eject the part from the insert, and to correlate those data to shrinkage of the polymer part, adhesion between polymer and mold surface and friction coefficient between those surfaces during the demolding stage. We also measured the influence the surface temperature of the part just before the demolding stage thanks to an infrared camera to investigate the thermal influence of these deposits in the injection process. Our results show an influence of deposits on demolding forces which is strongly dependent on nature of the polymer (of course) but also on its chemical nature. They also have a slight influence on temperature of the part even if they are only a few microns thick. We therefore developped a method to evaluate surface deposits and their impact on demolding forces, in terms of adhesion polymer/treament and friction.

Injection Molding Process Windows Considering Two Conflicting Criteria: Simulation Results

2012 ◽  
Author(s):  
Alicia B. Rodríguez ◽  
Esmeralda Niño ◽  
Jose M. Castro ◽  
Marcelo Suarez ◽  
Mauricio Cabrera
Keyword(s):  
Injection Molding ◽  
Multiple Criteria ◽  
Process Window ◽  
Injection Molding Process ◽  
Processing Conditions ◽  
Molding Process ◽  
Multiple Criteria Optimization ◽  
Simulation Results ◽  
Main Ideas

In this work, two criteria in conflict are considered simultaneously to determine a process window for injection molding. The best compromises between the two criteria are identified through the application of multiple criteria optimization concepts. The aim with this work is to provide a formal and realistic strategy to set processing conditions in injection molding operations. In order to keep the main ideas manageable, the development of the strategy is constrained to two controllable variables in computer simulated parts.

Simulation of Ceramic Injection Molding for Zirconia Optical Ferrule

2007 ◽  
Vol 336-338 ◽  
pp. 997-1000 ◽  
Author(s):  
Mei Min Zhang ◽  
Bin Lin
Keyword(s):  
Injection Molding ◽  
Injection Molding Process ◽  
Molding Process ◽  
Melt Temperature ◽  
Ceramic Injection Molding ◽  
Rectangular Distribution ◽  
Simulation Results ◽  
Die Temperature ◽  
Ram Speed ◽  
Short Shot

Zirconia Ferrule is a key part for manufacturing fiber connectors. The ceramic injection molding (CIM) process of the optical ferrule was simulated with the commercial CAE software moldflow. In order to obtain the optimum results, the orthogonal method was introduced to discuss the influence of each parameter such as die temperature, melt temperature, ram speed and gate dimension with the two kinds of distribution layout system respectively. The simulation results show that the curved distribution runner system is more suitable than the rectangular distribution one in the optical ferrule molding. Moreover, the effect of gravity on the ceramic injection molding process was discussed for determining a more reasonable balanced runner system of the special designed two-plate mold with six die cavities. It was found that short shot occurred at the top of the die cavity while other five cavities were filled well in the original designed mold. And when the top die cavity’s round runner with section diameter of 4.0mm was increased to 4.17 mm, each cavity was balanced filled without short shot.

In-Mold Monitoring of Temperature and Cavity Pressure During the Injection Molding Process

2014 ◽  
Author(s):  
Catalin Fetecau ◽  
Felicia Stan ◽  
Laurentiu I. Sandu
Keyword(s):  
Injection Molding ◽  
Pressure Sensors ◽  
Temperature Sensors ◽  
Injection Molding Process ◽  
Cavity Pressure ◽  
Molding Process ◽  
Shear Rates ◽  
Wide Range ◽  
Simulation Results ◽  
Two Temperature

This paper focuses on the in-mold monitoring of temperature and cavity pressure. The melt contact temperature and the cavity pressure along the flow path were directly measured using two pressure sensors and two temperature sensors fitted into the cavity of a spiral mold. Three melt temperatures and dies of different heights (1.0, 1.5 and 2 mm) were used to achieve a wide range of practically relevant shear rates. In order to analyze the extent to which the numerical simulation can predict the behavior of the molten polymer during the injection molding process, molding experiments were simulated using the Moldflow software and the simulation results were compared with the experimental data under the same injection molding conditions.

scholarly journals Physicomechanical behavior of composites of polypropylene, and mineral fillers with different process cycles

DYNA ◽  
2018 ◽  
Vol 85 (207) ◽  
pp. 260-268 ◽  
Author(s):  
Carolina Caicedo ◽  
Aldo Rafael Vázquez-Arce ◽  
Omar Hernán Ossa ◽  
Hever De La Cruz ◽  
Alfredo Maciel-Cerda
Keyword(s):  
Tensile Strength ◽  
Flexural Strength ◽  
Microstructural Analysis ◽  
Weight Ratio ◽  
Extrusion Process ◽  
Injection Molding Process ◽  
Molding Process ◽  
Injection Process ◽  
Degradation Temperature ◽  
Mineral Fillers

In this work, a development of composites of polypropylene [PP] with mineral fillers [M] of talc and calcium carbonate [CaCO3] by co-extrusion and injection techniques were carried out. In the preparation of the mixtures, was used the rheometric analysis to define the optimum temperature of the extrusion process, and a weight ratio of 80:20 PP: fillers was maintained, while for the injection molding process six generations of PP and its compounds were obtained to study the rheological, thermal, morphological and mechanical properties of the new series of PPnM composites formed from a recycled matrix and the PPMn series reprocessed compounds for up to six cycles. The results allowed correlating the changes due to the thermal history and the influence of adding the mineral fillers. The mechanical characterization in the reprocessed matrix indicated a 6.0% decrease in tensile strength and an increase in flexural strength of 9.9%. Likewise, the compounds showed an increase in tensile strength of 11.7%, while flexural strength reached 35.8%. From the thermogravimetric analysis, the degradation temperature in the matrix gradually decreased from 406.5 °C to 364.3 °C, for the sixth generation with respect to the virgin material by the injection process; meanwhile, for the compounds was maintained around 410 °C indicating an optimal interaction, these results could be contrasted with the colorimetric analysis. Finally, re-injection led to a significant decrease in the size of the talc and CaCO3 particles; the sizes were estimated from microstructural analysis from Scanning Electron Microscope.

Numerical Investigation on the Effect of Injection Pressure on Melt Front Pressure and Velocity Drop

2015 ◽  
Vol 786 ◽  
pp. 210-214
Author(s):  
M.S. Rusdi ◽  
Mohd Zulkifly Abdullah ◽  
A.S. Mahmud ◽  
C.Y. Khor ◽  
M.S. Abdul Aziz ◽  
...  
Keyword(s):  
Injection Molding ◽  
Cfd Simulation ◽  
Fluid Dynamic ◽  
Injection Pressure ◽  
Simulation Software ◽  
Mold Cavity ◽  
Injection Molding Process ◽  
Flow Profile ◽  
Molding Process ◽  
Injection Process

Computational Fluid Dynamic (CFD) was used to simulate the injection molding process of a tray. The study focuses on pressure distribution and velocity drop during the injection process. CFD simulation software ANSYS FLUENT 14 was utilized in this study. The melt front pressure in the mold cavity shows that it was affected by the shape of mold cavity and filling stage. The melt front pressure will decrease as the flow move further than the sprue but it will increase rapidly when the mold was about to be fully filled. The slight pressure drop was detected when the molten flow meets the rib of the tray. The velocity of higher injection pressure was greater than the lower injection pressure but the velocity rapidly dropped when the melt front fully filled the cavity. The current predicted flow profile was validated by the experimental results, which demonstrates the excellent capability of the simulation tool in solving injection-molding problems.

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.

An Application of Computer Aided Engineering in Rubber Injection Mold With a Cold Runner System Design and Manufacturing

2007 ◽  
Author(s):  
Supasit Rodkwan ◽  
Rungtham Panyawipart ◽  
Chana Raksiri ◽  
Kunnayut Eiamsa-ard
Keyword(s):  
Injection Molding ◽  
Raw Material ◽  
Injection Molding Process ◽  
Molding Process ◽  
Actual System ◽  
Part Quality ◽  
Injection Process ◽  
Design And Manufacturing ◽  
Trial And Error Method ◽  
And Behavior

With a recent growth in the demand of the rubber products globally, the latest technology is adopted to improve the design and manufacturing of those rubber products in term of part quality and production lead time and cost. The cold runner system is one of the technologies which can assist in unfilling part problem and raw material saving. Nevertheless, with the lack of numerical tool with an ability to predict the behavior of rubber during the injection molding process, designers still need to use their experience and trial-and-error method to design the mold and the cold runner system. Therefore, in this research, the use of CAE and a cold runner system is applied to the design and manufacturing of rubber injection molding process with a gasket mold made of SBR as a case study. The empirical and simulated results agree well and the use of raw material in the actual system is decreased by 12% shot weight which can lead to the reduced cost of products. Finally, it can be seen that the use of CAE can assist the mold designers and manufacturers to get better understanding of flow pattern and behavior of rubber during the injection process so the better part quality can be obtained.

scholarly journals Double-Sided Freeform Lens for Light Collimation of Light Emitting Diodes

2019 ◽  
Vol 9 (24) ◽  
pp. 5452
Author(s):  
Yong-Sin Syu ◽  
Chun-Ying Wu ◽  
Yung-Chun Lee
Keyword(s):  
Light Emitting Diodes ◽  
Uv Light ◽  
Design Parameters ◽  
Injection Molding Process ◽  
Light Sources ◽  
Molding Process ◽  
Light Emitting ◽  
Uv Led ◽  
Simulation Results ◽  
Freeform Lens

A double-sided freeform lens is proposed for collimating light emitted from light emitting diodes (LEDs). The surface profiles of the lens are mathematically characterized and precisely determined based on a point-source assumption and differential geometry theory. The proposed lens design method is straightforward, flexible, and effective. Moreover, the optical performance of the lens can be intuitively adjusted by tuning just a small number of design parameters. The simulation results showed that the proposed lens achieved an excellent collimating effect for a commercial ultraviolet (UV) LED. A prototype lens is fabricated in UV-grade poly(methyl methacrylate) material using a standard injection molding process. The light collimating effect of the lens/UV-LED assembly was measured experimentally and was shown to be in good agreement with the simulation results. The collimating angle at the half-energy level was equal to 1.88°. The performance of the UV-LED is thus comparable to that of conventional lithography UV light sources based on mercury arc lamps. Consequently, the proposed double freeform lens showed significant potential for photolithography applications within the industry.

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