Fiber orientation and material properties analysis in injection molding.

This study analyzes the fundamental principles and characteristics of the microcellular foaming process (MCP) to minimize warpage in glass fiber reinforced polymer (GFRP), which is typically worse than that of a solid polymer. In order to confirm the tendency for warpage and the improvement of this phenomenon according to the glass fiber content (GFC), two factors associated with the reduction of the shrinkage difference and the non-directionalized fiber orientation were set as variables. The shrinkage was measured in the flow direction and transverse direction, and it was confirmed that the shrinkage difference between these two directions is the cause of warpage of GFRP specimens. In addition, by applying the MCP to injection molding, it was confirmed that warpage was improved by reducing the shrinkage difference. To further confirm these results, the effects of cell formation on shrinkage and fiber orientation were investigated using scanning electron microscopy, micro-CT observation, and cell morphology analysis. The micro-CT observations revealed that the fiber orientation was non-directional for the MCP. Moreover, it was determined that the mechanical and thermal properties were improved, based on measurements of the impact strength, tensile strength, flexural strength, and deflection temperature for the MCP.

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The Effect of Heat Treatment on Mechanical Properties of Car Interior Fabric Used for Injection Molding

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.532-533.234 ◽

2012 ◽

Vol 532-533 ◽

pp. 234-237

Author(s):

Wei Lai Chen ◽

Ding Hong Yi ◽

Jian Fu Zhang

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

High Temperature ◽

Injection Molding ◽

High Temperatures ◽

Material Properties ◽

Injection Molding Process ◽

Molding Process ◽

Composite Fabrics

The purpose of this paper is to study the effect of high temperature in injection molding process on mechanical properties of the warp-knitted and nonwoven composite fabrics (WNC)used in car interior. Tensile, tearing and peeling properties of WNC fabrics were tested after heat treatment under120, 140,160,180°C respectively. It was found that, after 140°C heat treatment, the breaking and tearing value of these WNC fabrics are lower than others. The results of this study show that this phenomenon is due to the material properties of fabrics. These high temperatures have no much effect on peeling properties of these WNC fabrics. It is concluded that in order to preserve the mechanical properties of these WNC fabrics, the temperature near 140°C should be avoided possibly during injection molding process.

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Fiber orientation in divergent/convergent flows in expansion and compression injection molding

Polymer Composites ◽

10.1002/pc.20152 ◽

2006 ◽

Vol 27 (5) ◽

pp. 539-551 ◽

Cited By ~ 12

Author(s):

Cristina A. Silva ◽

Júlio C. Viana ◽

Ferrie W.J. van Hattum ◽

António M. Cunha

Keyword(s):

Injection Molding ◽

Fiber Orientation

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Fiber orientation prediction in injection molding

Polypropylene Structure, blends and Composites ◽

10.1007/978-94-011-0523-1_3 ◽

1995 ◽

pp. 113-141 ◽

Cited By ~ 4

Author(s):

T. Matsuoka

Keyword(s):

Injection Molding ◽

Fiber Orientation

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Investigation on the Fiber Orientation Distributions and Their Influence on the Mechanical Property of the Co-Injection Molding Products

Polymers ◽

10.3390/polym12010024 ◽

2019 ◽

Vol 12 (1) ◽

pp. 24

Author(s):

Chao-Tsai Huang ◽

Xuan-Wei Chen ◽

Wei-Wen Fu

Keyword(s):

Injection Molding ◽

Tensile Properties ◽

Fiber Orientation ◽

Flow Direction ◽

Rapid Development ◽

Injection System ◽

Single Shot ◽

Fiber Morphology ◽

Orientation Tensor ◽

Orientation Distributions

In recent years, due to the rapid development of industrial lightweight technology, composite materials based on fiber reinforced plastics (FRP) have been widely used in the industry. However, the environmental impact of the FRPs is higher each year. To overcome this impact, co-injection molding could be one of the good solutions. But how to make the suitable control on the skin/core ratio and how to manage the glass fiber orientation features are still significant challenges. In this study, we have applied both computer-aided engineering (CAE) simulation and experimental methods to investigate the fiber feature in a co-injection system. Specifically, the fiber orientation distributions and their influence on the tensile properties for the single-shot and co-injection molding have been discovered. Results show that based on the 60:40 of skin/core ratio and same materials, the tensile properties of the co-injection system, including tensile stress and modulus, are a little weaker than that of the single-shot system. This is due to the overall fiber orientation tensor at flow direction (A11) of the co-injection system being lower than that of the single-shot system. Moreover, to discover and verify the influence of the fiber orientation features, the fiber orientation distributions (FOD) of both the co-injection and single-shot systems have been observed using micro-computerized tomography (μ-CT) technology to scan the internal structures. The scanned images were further utilizing Avizo software to perform image analyses to rebuild the fiber structure. Specifically, the fiber orientation tensor at flow direction (A11) of the co-injection system is about 89% of that of the single-shot system in the testing conditions. This is because the co-injection part has lower tensile properties. Furthermore, the difference of the fiber orientation tensor at flow direction (A11) between the co-injection and the single-shot systems is further verified based on the fiber morphology of the μ-CT scanned image. The observed result is consistent with that of the FOD estimation using μ-CT scan plus image analysis.

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Numerical prediction of fiber orientation in injection molding

Polymer Engineering & Science ◽

10.1002/pen.760320405 ◽

1992 ◽

Vol 32 (4) ◽

pp. 254-266 ◽

Cited By ~ 28

Author(s):

H. Henry De Frahan ◽

V. Verleye ◽

F. Dupret ◽

M. J. Crochet

Keyword(s):

Injection Molding ◽

Fiber Orientation ◽

Numerical Prediction

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Process comparison on the microstructure and mechanical properties of fiber-reinforced polyphenylene sulfide using MuCell technology

Journal of Reinforced Plastics and Composites ◽

10.1177/0731684418777120 ◽

2018 ◽

Vol 37 (15) ◽

pp. 1020-1034 ◽

Cited By ~ 3

Author(s):

Christoph Lohr ◽

Björn Beck ◽

Frank Henning ◽

Kay André Weidenmann ◽

Peter Elsner

Keyword(s):

Mechanical Properties ◽

High Pressure ◽

Injection Molding ◽

Fiber Orientation ◽

Polyphenylene Sulfide ◽

Injection Molding Process ◽

Fiber Reinforced ◽

Molding Process ◽

Glass Fiber Reinforced ◽

Foam Injection Molding

The MuCell process is a special injection molding process which utilizes supercritical gas (nitrogen) to create integral foam sandwiches. The advantages are lower weight, higher specific properties and shorter cycle times. In this study, a series of glass fiber-reinforced polyphenylene sulfide foam blanks are manufactured using the MuCell injection molding process. The different variations of the process (low-pressure also known as structural foam injection molding) and high-pressure foam injection molding (also known as “core back expansion,” “breathing mold,” “precision opening,” decompression molding) are used. The sandwich structure and mechanical properties (tensile strength, bending strength, and impact behavior) of the microcellular and glass fiber-reinforced polyphenylene sulfide foams are systematically investigated and compared to compact material. The results showed that the injection parameters (injection speed, foaming mechanism) played an important role in the relative density of microcellular polyphenylene sulfide foams and the mechanical properties. It could be shown that the specific tensile strength decreased while increasing the degree of foaming which can be explained by the increased number of cells and the resulting cell size. This leads to stress peaks which lower the mechanical properties. The Charpy impact strength shows a significant dependence on the fiber orientation. The specific bending modulus of the high-pressure foaming process, however, surpasses the values of the other two processes showing the potential of this manufacturing variation especially with regard to bending loads. Furthermore, a high dependence of the mechanical properties on the fiber orientation of the tested specimens can be found.

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