Use of medial axis to find optimal channel designs to reduce mold filling time in resin transfer molding

2017 ◽  
Vol 95 ◽  
pp. 161-172 ◽  
Author(s):  
J. Wang ◽  
P. Simacek ◽  
S.G. Advani
Keyword(s):  
Medial Axis ◽  
Resin Transfer Molding ◽  
Mold Filling ◽  
Transfer Molding ◽  
Filling Time

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.

Effects of Weirs on the Resin Transfer Molding Process

2001 ◽  
Author(s):  
Kiran M. D’Silva ◽  
Su-Seng Pang ◽  
Kurt C. Schulz
Keyword(s):  
Glass Fibers ◽  
Resin Transfer Molding ◽  
Mold Filling ◽  
Laminated Plates ◽  
Molding Process ◽  
Outlet Port ◽  
Transfer Molding ◽  
Inlet Port ◽  
Rtm Process ◽  
Filling Time

Abstract Low mold filling time and improper fiber wetting are the main problems faced by the manufacturers applying the Resin Transfer Molding (RTM) process. The objective of this work was to minimize these problems and to study the effect of weirs on the RTM process. A mold was designed such that the lower mold plate contains two weirs, one at the resin inlet port and the other at the outlet port. The purpose of adding the weirs is to provide a continuous inlet stream near the resin inlet port and to cause backpressure near the outlet port to induce complete mold filling. Laminated plates were prepared using glass fibers and epoxy resin (combination of EPON resin-862 and curing agent W). The test parameters investigated, such as void contents, dry spots and mold filling time, were compared with those of samples that were prepared without the use of weirs. It was found that the presence of weirs resulted in significant elimination of dry spots, minimization of void contents and a reduction in mold filling time. As a result, the cost required to manufacture composite parts can be reduced by the use of weirs. In addition to the experimental investigation, a computer simulation (using LCMFLOT software) of resin flow inside the mold cavity was conducted. Many simulations were run in order to optimize the height and shape of the weir. Rectangular weirs of height 2.54 mm showed minimum mold fill time. It was found that the results obtained from the experimental work and flow simulations are in good agreement. Based on this work, it is evident that complex parts can be produced in less cycle time if weirs are positioned at appropriate locations.

Flow and Mold Filling Modeling and Simulation to Enhance Resin Transfer Molding Processes

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
C. J. Mosella ◽  
J. P. Montecinos ◽  
J. A. Ramos-Grez
Keyword(s):  
Resin Transfer Molding ◽  
Mass Conservation ◽  
Mold Filling ◽  
Complete Wetting ◽  
Air Bubble ◽  
Transfer Molding ◽  
Numerical Resolution ◽  
Filling Time ◽  
Manufacturing Time

Among the multiple stages of the resin transfer molding (RTM) processes, flow and mold filling of injected resin correspond to the most complex and crucial stage. During the latter, air bubble agglomeration must be avoided and complete wetting of fibers must be achieved in order to ensure the maximum quality of the parts at the lowest possible manufacturing time. Focusing on these manufacturing issues, a mathematical model and a numerical resolution are presented to predict the resin flow throughout the fiber reinforcement inside the mold cavity. The methodology employs conventional finite element techniques for solving the flow problem through a porous medium governed by Darcy’s law and mass conservation. Simultaneously, a state of the art numerical scheme known as the discontinuous Galerkin method is implemented to determine the location and shape of the advancing flow fronts ruled by a hyperbolic transport equation. These two schemes are implemented to work with a two-dimensional domain, handling diverse geometries with multiple injection and ventilation ports. The results for key process parameters, such as filling time and position of the advancing flow fronts, show a good agreement with results from analytical solutions for particular cases and from empirical data. When several simulated results are taken into account in the design process of RTM cavities, the overall process could be enhanced.

A Study on Resin Flow through a Multi-layered Preform in Resin Transfer Molding

2002 ◽  
Vol 10 (7) ◽  
pp. 493-510 ◽  
Author(s):  
D. G. Seong ◽  
K Chung ◽  
T. J. Kang ◽  
J. R. Youn
Keyword(s):  
Resin Transfer Molding ◽  
Mold Filling ◽  
Transverse Flow ◽  
Woven Fabrics ◽  
Weighted Averaging ◽  
Resin Flow ◽  
Flow Front ◽  
Transfer Molding ◽  
Filling Time ◽  
Flow Through

In resin transfer molding, mold filling is governed by the flow of resin through a preform which is considered as an anisotropic porous media. The resin flow is usually described by Darcy's law and the permeability tensor must be obtained for filling analysis. When the preform is composed of more than two layers with different in-plane permeability, effective average permeability should be determined for the flow analysis in the mold. The most frequently used averaging scheme is the weighted averaging scheme, but it does not account for the transverse flow between adjacent layers. A new averaging scheme is suggested to predict the effective average permeability of the multi-layered preform, which accounts for the transverse flow effect. When the flow in the mold is unsaturated, the effective average permeability is predicted by using the predicted mold filling time and transverse permeability. The new scheme is verified by measuring the effective permeability of the multi-layered preforms which consist of glass fiber random mats, carbon fiber woven fabrics, aramid fiber woven fabrics. Fluid flow through the preform composed of more than two layers with different in-plane permeability shows different flow fronts between layers. The difference in the flow front advancement is observed with a digital camcorder. The predicted flow front is compared with the experimental results and shows a good agreement. It is expected that the effective average permeability can be used for modeling the resin flow through the multi-layered preform.

Analysis of Resin Transfer Molding With High Permeability Layers

1998 ◽  
Vol 120 (3) ◽  
pp. 609-616 ◽  
Author(s):  
M. J. Tari ◽  
J. P. Imbert ◽  
M. Y. Lin ◽  
A. S. Lavine ◽  
H. T. Hahn
Keyword(s):  
Complex Geometry ◽  
Resin Transfer Molding ◽  
Mold Filling ◽  
Process Efficiency ◽  
High Permeability ◽  
Capital Costs ◽  
Transfer Molding ◽  
Analysis Experiment ◽  
Filling Time ◽  
Two Dimensional Flow

In resin transfer molding (RTM) a high permeability layer (HPL) is placed on top of the fiber mat lay-up to reduce mold filling time and increase the ultimate distance resin can be drawn into the mold. HPL’s are particularly useful in vacuum bag resin transfer molding (VBRTM), where driving pressures are relatively low. When compared to traditional closed mold RTM, VBRTM has the advantages of low capital costs and short start up time. The goal of the current research is to investigate how an HPL can be used to improve quality and process efficiency for parts of complex geometry made by both conventional and vacuum bag RTM. As a first step towards this goal, the effect of the HPL on the flow field has been studied through analysis, experiment and simulation. As expected, the use of the HPL creates a transverse (i.e., top-to-bottom) flow in the fiber mat, facilitating mold filling. The thickness of the HPL has been varied to determine the effects on the flow front. The experimental results validate the capability of the simulation to model two-dimensional flow in a porous medium with heterogeneous permeability.

A Theoretical Analysis on Resin Injection/Compression Molding

2007 ◽  
Vol 334-335 ◽  
pp. 209-212 ◽  
Author(s):  
Akbar Shojaei ◽  
A. Spah
Keyword(s):  
Analytical Solutions ◽  
Mold Filling ◽  
Compression Molding ◽  
Fiber Content ◽  
Flow Front ◽  
Transfer Molding ◽  
Unidirectional Flow ◽  
Resin Injection ◽  
Filling Time ◽  
Injection Compression Molding

In the present investigation, mold filling process of resin injection/compression molding (RI/CM) is compared with resin transfer molding (RTM) for simple mold geometry. To do this, analytical solutions are obtained for RI/CM in unidirectional flow. Based on the analytical solutions, flow front progression and pressure distribution are compared with RTM at different fiber content. The results indicate that the RI/CM reduces the mold filling time significantly, particularly for composite parts with higher fiber content.

scholarly journals COMPUTATIONAL MODELING OF RTM AND LRTM PROCESSES APPLIED TO COMPLEX GEOMETRIES

2012 ◽  
Vol 11 (1-2) ◽  
pp. 93 ◽  
Author(s):  
J. Da S. Porto ◽  
M. Letzow ◽  
E. D. Dos Santos ◽  
S. C. Amico ◽  
J. A. Souza ◽  
...  
Keyword(s):  
Porous Medium ◽  
Flow Behavior ◽  
Resin Transfer Molding ◽  
Three Dimensional ◽  
Complex Geometries ◽  
Resin Flow ◽  
Transfer Molding ◽  
Rtm Process ◽  
General Terms ◽  
Filling Time

Light Resin Transfer Molding (LRTM) is a variation of the conventional manufacturing process known as Resin Transfer Molding (RTM). In general terms, these manufacturing processes consist of a closed mould with a preplaced fibrous preform through which a polymeric resin is injected, filling the mold completely, producing parts with complex geometries (in general) and good finish. Those processes differ, among other aspects, in the way that injection occurs. In the RTM process the resin is injected through discrete points whereas in LRTM it is injected into an empty channel (with no porous medium) which surrounds the entire mold perimeter. There are several numerical studies involving the RTM process but LRTM has not been explored enough by the scientific community. Based on that, this work proposes a numerical model developed in the FLUENT package to study the resin flow behavior in the LRTM process. Darcy’s law and Volume of Fluid method (VOF) are used to treat the interaction between air and resin during the flow in the porous medium, i.e. the mold filling problem. Moreover, two three-dimensional geometries were numerically simulated considering the RTM and LRTM processes. It was possible to note the huge differences about resin flow behavior and filling time between these processes to manufacture the same parts.

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