Flow Characteristics of Vacuum Assisted Resin Transfer Molding Process Depending on the Capillary Phenomenon

2013 ◽  
Vol 762 ◽  
pp. 612-620 ◽  
Author(s):  
Yun Hae Kim ◽  
Jin Woo Lee ◽  
Jun Mu Park
Keyword(s):  
Low Cost ◽  
Resin Transfer Molding ◽  
Flow Characteristics ◽  
Molding Process ◽  
Transfer Molding ◽  
Filling Stage ◽  
Resin Impregnation ◽  
Movement Mechanism ◽  
Capillary Phenomenon ◽  
Vartm Process

Reducing the cost of composite material production is significant for expanding its usage and application in many ways, such as in the fields of aerospace, aviation, ocean industry and so on. To do this, It is important to minimize the production process of the material and to decrease the amount of scraps or any unnecessary particles. The Vacuum Assisted Resin Transfer Molding (VARTM) process, which is known for having many advantages, has become recognized as one of the most low-cost manufacturing model. VARTM process can be divided into three main steps: performing, resin filling and hardening steps. The most important step among all these three steps is the Resin Filling stage, a process when resin is impregnated into the mat. Mostly, Resin Filling stage is greatly affected by the level of permeability, a characteristic of stiffener due to pneumatic resistant nature in the process. Other factors such as viscosity, technological vacuuming, or even stiffening process itself could also influence the production as well. During Resin Filling stage, Resin tends to spread out in the center first because of capillary phenomenon. In this research, the researchers examined the mechanical property and the pneumatic nature of Resin by dividing the pneumatic movement of the Resin into sections. Based on this result, the researchers found the correlations between the capillary phenomenon and Resin impregnation, and analyzed the movement mechanism in Resin filling stage.

The Thickness and the Inerior Quality of Composite Panel in the Vacuum Assisted Resin Transfer Molding Process

2011 ◽  
Vol 686 ◽  
pp. 468-473
Author(s):  
Yan Liang Li ◽  
Xiao Su Yi ◽  
Bang Ming Tang
Keyword(s):  
Fiber Composite ◽  
Low Cost ◽  
Resin Transfer Molding ◽  
Composite Panel ◽  
Flow Front ◽  
Carbon Fiber Composite ◽  
Molding Process ◽  
Transfer Molding ◽  
Vartm Process

The objective of this paper was focused on predicting the thickness and the interior quality of carbon fiber composite panel during the vacuum assisted resin transfer molding (VARTM) process. The character of the VARTM process determined that it was low cost. A panel made of Epoxy resin, and carbon fibers, was used as the simplest article to experiment and except routine items, the thickness and the interior quality was focused. In the process, the flow front of the resin was record using a digital camera. Darcy’s law was the model of resin flow. The results showed that the flow front history would reach unanimous, thickness near the edges was difficult to control, and most of the porosity came from the injection line where more resin cumulated.

On-Line Characterization of Bulk Permeability and Race-Tracking During the Filling Stage in Resin Transfer Molding Process

2003 ◽  
Vol 37 (17) ◽  
pp. 1525-1541 ◽  
Author(s):  
Mathieu Devillard ◽  
Kuang-Ting Hsiao ◽  
Ali Gokce ◽  
Suresh G. Advani
Keyword(s):  
Resin Transfer Molding ◽  
Molding Process ◽  
Transfer Molding ◽  
Filling Stage ◽  
On Line

scholarly journals NUMERICAL ANALYSIS OF INFUSION STRATEGIES IN VACUUM ASSISTED RESIN TRANSFER MOLDING (VARTM) PROCESS

2021 ◽  
Vol 13 (3) ◽  
pp. 117-124
Author(s):  
Himanshu V. Patel ◽  
◽  
Harshit K. Dave ◽  
Keyword(s):  
Resin Transfer Molding ◽  
Mold Filling ◽  
Vital Role ◽  
Simulation Approach ◽  
Gating System ◽  
Composite Manufacturing ◽  
Transfer Molding ◽  
Filling Stage ◽  
Filling Time ◽  
Vartm Process

The Liquid composite Molding (LCM) process, such as Vacuum Assisted Resin Transfer Molding (VARTM), offers a fast and high-quality production of composites laminates. In the VARTM process, the simulation tool is found beneficial to predict and solve composite manufacturing issues. The part quality is dependent on the resin mold filling stage in the VARTM process. The infiltration of resin into a porous fibrous medium is taken place during the resin mold filling stage. The permeability has a crucial role during the resin mold filling stage. In this study, simulation of resin infusion through multiple injection gates is discussed. The various infusion schemes are simulated to identify defect-free composite manufacturing. The simulation approach is applied to five different stacking sequences of reinforcements. In this transient simulation study, permeability and resin viscosity is essential inputs for the resin flow. The simulation approach found that a gating scheme plays a vital role in mold filling time and defect-free composite fabrication. It is found that the line gating system can be useful for fast mold filling over the point gating system.

Fabrication of T-Shaped Structural Composite through Resin Transfer Molding

1995 ◽  
Vol 29 (16) ◽  
pp. 2192-2214 ◽  
Author(s):  
Wen-Bin Young ◽  
Min-Te Chuang
Keyword(s):  
Low Cost ◽  
Resin Transfer Molding ◽  
Mold Filling ◽  
Transfer Molding ◽  
Rtm Process ◽  
Resin Impregnation ◽  
Composite Fabrication ◽  
Fiber Reinforcements ◽  
Fiber Materials ◽  
Dry Spot

Resin transfer molding (RTM) combines resin impregnation and composite fabrication in one process. It simplifies the process for composite fabrication and has the advantages of automation, low cost, and versatile design of fiber reinforcements. The RTM process was used in this study to fabricate T-shaped stuctural composites. Edge effects due to the gap between the fiber mats and the mold or the imperfect sealing of the matting mold resulted in edge channeling flows, leading to dry spot enclosure in the composite. It was found that a vacuum in the mold cavity could reduce the size of the dry spot. Proper control or prevention of the edge flows will reduce the possibility of dry spot formation. Numerical simulations of the mold filling were conducted to study the effect of gate locations on the mold filling patterns and edge channeling flows. Mechanical pulling tests were conducted to investigate the joint strengths of the T-shaped structure for different fiber materials. Fiber stitching on the rib provided an improvement in the joint strength while different fiber materials without fiber stitching tended to have the same joint strengths.

Use of Resin Transfer Molding Simulation to Predict Flow, Saturation, and Compaction in the VARTM Process

2004 ◽  
Vol 126 (2) ◽  
pp. 210-215 ◽  
Author(s):  
N. C. Correia ◽  
F. Robitaille ◽  
A. C. Long ◽  
C. D. Rudd ◽  
P. Sˇima´cˇek ◽  
...  
Keyword(s):  
Resin Transfer Molding ◽  
Flow Simulation ◽  
Continuity Condition ◽  
Simulation Software ◽  
Molding Process ◽  
Numerical Work ◽  
Transfer Molding ◽  
Outlet Pressure ◽  
Analytical Work ◽  
Vartm Process

The present paper examines the analysis and simulation of the vacuum assisted resin transfer molding process (VARTM). VARTM differs from the conventional resin transfer molding (RTM) in that the thickness of the preform varies during injection affecting permeability and fill time. First, a governing equation for VARTM is analytically developed from the fundamental continuity condition, and used to show the relation between parameters in VARTM. This analytical work is followed by the development of a numerical 1-D/2-D solution, based on the flow simulation software LIMS, which can be used to predict flow and time dependent thickness of the preform by introducing models for compaction and permeability. Finally, the results of a VARTM experimental plan, focusing on the study of the influence of outlet pressure on compaction and fill time, are correlated with both the analytical and the numerical work. The present work also proposes an explanation for the similarities between VARTM and RTM and shows when modeling VARTM and RTM can result in an oversimplification.

Use of Resin Transfer Molding Simulation to Predict Flow, Saturation and Compaction in the VARTM Process

2002 ◽  
Author(s):  
N. C. Correia ◽  
F. Robitaille ◽  
A. C. Long ◽  
C. D. Rudd ◽  
P. Sˇima´cˇek ◽  
...  
Keyword(s):  
Resin Transfer Molding ◽  
Molding Process ◽  
Transfer Molding ◽  
Injection Process ◽  
Software Packages ◽  
Compaction Force ◽  
Thickness Variations ◽  
Filling Simulation ◽  
Complex Parts ◽  
Vartm Process

Vacuum Assisted Resin Transfer Molding (VARTM) and Resin Transfer Molding (RTM) are among the most significant and widely used Liquid Composite manufacturing processes. In RTM preformed-reinforcement materials are placed in a mold cavity, which is subsequently closed and infused with resin. RTM numerical simulations have been developed and used for a number of years for gate assessment and optimization purposes. Available simulation packages are capable of describing/predicting flow patterns and fill times in geometrically complex parts manufactured by the resin transfer molding process. Unlike RTM, the VARTM process uses only one sided molds (tool surfaces) where performs are placed and enclosed by a sealed vacuum bag. To improve the delivery of the resin, a distribution media is sometimes used to cover the preform during the injection process. Attempts to extend the usability of the existing RTM algorithms and software packages to the VARTM domain have been made but there are some fundamental differences between the two processes. Most significant of these are 1) the thickness variations in VARTM due to changes in compaction force during resin flow 2) fiber tow saturation, which may be significant in the VARTM process. This paper presents examples on how existing RTM filling simulation codes can be adapted and used to predict flow, thickness of the preform during the filling stage and permeability changes during the VARTM filling process. The results are compared with results obtained from an analytic model as well as with limited experimental results. The similarities and differences between the modeling of RTM and VARTM process are highlighted.

Application of Calcium Carbonate in Resin Transfer Molding Process

2014 ◽  
Vol 353 ◽  
pp. 39-43 ◽  
Author(s):  
Iran Rodrigues de Oliveira ◽  
Sandro Campos Amico ◽  
R. Barcella ◽  
Antônio Gilson Barbosa de Lima
Keyword(s):  
Calcium Carbonate ◽  
Low Cost ◽  
Resin Transfer Molding ◽  
Injection Pressure ◽  
Molding Process ◽  
Transfer Molding ◽  
Industrial Sectors ◽  
Advanced Composite Materials ◽  
Filling Time ◽  
Manufacturing Techniques

Resin Transfer Molding (RTM) is one of the most widely known composite manufacturing techniques of the liquid molding family, being extensively studied and used to obtain advanced composite materials comprised of fibers embedded in a thermoset polymer matrix. Nowadays, RTM is used by many industrial sectors such as automotive, aerospace, civil and sporting equipment. Therefore, the objective of this study is to verify the effect of calcium carbonate mixed in resin in the RTM process. Several rectilinear infiltration experiments were conducted using glass fiber mat molded in a RTM system with cavity dimensions of 320 x 150 x 3.6 mm, room temperature, maximum injection pressure 0.202 bar and different content of CaCO3 (10 and 40%) with particle size of 75μm. The results show that the use of filled resin with CaCO3 influences the preform impregnation during the RTM molding, changing the filling time and flow from position, however it is possible to make the composite with a good quality and low cost.

Effect of CaCO3 Content in Resin Transfer Molding Process

2013 ◽  
Vol 334-335 ◽  
pp. 188-192 ◽  
Author(s):  
Iran Rodrigues de Oliveira ◽  
Sandro Campos Amico ◽  
F. Ferreira Luz ◽  
R. Barcella ◽  
V.M. França Bezerra ◽  
...  
Keyword(s):  
Porous Media ◽  
Low Cost ◽  
Resin Transfer Molding ◽  
Molding Process ◽  
Transfer Molding ◽  
Advanced Composite ◽  
Rtm Process ◽  
Advanced Composite Materials ◽  
Closed Mold ◽  
The Individual

Composite material can be defined as a combination of two or more materials on a macroscale to form a useful material, often showing properties that none of the individual independent components shows. Resin Transfer Molding (RTM) is one of the most widely known composite manufacturing technique of the liquid molding family, being extensively studied and used to obtain advanced composite materials comprised of fibers embedded in a thermoset polymer matrix. This technique consists in injecting a resin pre-catalysed thermosetting in a closed mold containing a dry fiber preform, where the resin is impregnated. The aim of this study is to investigate the effect caused by the use of CaCO3filled resin on the characteristics of the RTM process. Several experiments were conducted using glass fiber mat and polyester resin molded in a RTM system with cavity dimensions of 320 x 150 x 3.6 mm, at room temperature, and different CaCO3content (0, 10, 20, 30 and 40% in weight). The results show that the use of filled resin with CaCO3influences the resin viscosity and the porous media permeability, making it difficult to fill the porous media during the molding process, however it is possible to make composite with a good quality and low cost.

Study on Compression Transfer Molding

1995 ◽  
Vol 29 (16) ◽  
pp. 2180-2191 ◽  
Author(s):  
Wen-Bin Young ◽  
Cheng-Wey Chiu
Keyword(s):  
Low Cost ◽  
Fiber Reinforcement ◽  
Mold Filling ◽  
Thickness Direction ◽  
Molding Process ◽  
Transfer Molding ◽  
Rtm Process ◽  
Resin Impregnation ◽  
Filling Time ◽  
Part Dimension

Resin transfer molding (RTM) finishes the resin impregnation and composite fabrication at the same time. It simplifies the process for composites fabrication and has the advantages of automation, low cost, and versatile design of fiber reinforcement. Therefore, the RTM process is widely used in the architecture, automotive, and aerospace industries. However, in the RTM process, resin must flow through the fiber reinforcement in the planar direction, which, in some cases such as fabrications of large panels, may need a long time for the mold filling. If the part dimension is too large or the fiber permeability is too low, the mold filling process may not be able to complete before the resin gels. Therefore, some modification for the RTM process is necessary in order to reduce the mold filling time. In the compression transfer molding, the mold opens a small gap for the resin to fill in between fiber mats and the mold, and then compresses the fiber reinforcement to be impregnated by the resin in the thickness direction. In this way, since resin is forced into the fiber reinforcements in the thickness direction, the damage of the fibers will be minimized. In addition, the mold filling time will be reduced due to the different flow path of the resin inside the mold. This study explored the possibility of using the compression transfer molding process and also identified the key parameters regarding the process.

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