scholarly journals Curing kinetics and viscosity change of a two-part epoxy resin during mold filling in resin-transfer molding process

2000 ◽  
Vol 77 (10) ◽  
pp. 2139-2148 ◽  
Author(s):  
Chang-Lun Lee ◽  
Kung-Hwa Wei
Keyword(s):  
Epoxy Resin ◽  
Resin Transfer Molding ◽  
Curing Kinetics ◽  
Mold Filling ◽  
Molding Process ◽  
Viscosity Change ◽  
Transfer Molding

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.

Effects of Graphene on a Resin Transfer Molding Process Using Bisphenol A Based Epoxy Resin

2010 ◽  
Vol 123-125 ◽  
pp. 535-538
Author(s):  
Huu Hieu Nguyen ◽  
Dae Woo Lee ◽  
Quang Trung Troung ◽  
Seong Woo Yun ◽  
Chi Hoon Choi ◽  
...  
Keyword(s):  
Bisphenol A ◽  
Epoxy Resin ◽  
Polymer Composites ◽  
Epoxy Resins ◽  
Resin Transfer Molding ◽  
Analysis Tool ◽  
Molding Process ◽  
Liquid Resin ◽  
Transfer Molding ◽  
Computational Fluid Dynamics Analysis

Resin transfer molding is a popular process to fabricate polymer composites reinforced with a large amount of glass or carbon fibers. In general, fiber reinforcements are put in a mold, and a liquid resin such as epoxy resin is injected into the mold after preheating. For successful production of polymer composites via a resin transfer molding process, the filling and curing stages of the liquid resin as well as the mold design should be optimized. Recently, polymer composites reinforced with nanoparticles are attracting attention of researchers in academia and industries because efficient reinforcement can be achieved by small loading of nanoparticles such as carbon nanotubes and exfoliated clays. In this work, as an effort to develop light weight automotive parts, graphenes were investigated as a nano size reinforcement of epoxy resin for resin transfer molding. Graphenes were prepared from graphites by microwave irradiation. Addition of graphenes to bisphenol A based epoxy resins such as YD-128 from Kukdo Chemical results in an increase in viscosity and shear thinning behavior, affecting the filling process. The curing of epoxy resins is also affected by graphenes. In order to develop a model for simulation of the filling and curing of epoxy resins containing different amounts of graphenes in the resin transfer molding, FLUENT and MATLAB have been used in this study, which are a finite element based computational fluid dynamics analysis tool and a general purpose numerical analysis tool, respectively. The effects of graphenes on the mold filling pattern and curing profile are discussed for the resin transfer molding of bisphenol A based epoxy resins.

scholarly journals Comparison of in-plane resin transfer molding and vacuum-assisted resin transfer molding ‘effective’ permeabilities based on mold filling experiments and simulations

2019 ◽  
Vol 39 (1-2) ◽  
pp. 31-44 ◽  
Author(s):  
Mert Hancioglu ◽  
E Murat Sozer ◽  
Suresh G Advani
Keyword(s):  
Effective Permeability ◽  
Thickness Distribution ◽  
Resin Transfer Molding ◽  
Mold Filling ◽  
Flow Patterns ◽  
Resin Flow ◽  
Liquid Composite Molding ◽  
Molding Process ◽  
Coupled Models ◽  
Transfer Molding

Resin transfer molding and vacuum-assisted resin transfer molding are two of the most commonly used liquid composite molding processes. For resin transfer molding, mold filling simulations can predict the resin flow patterns and location of voids and dry spots which has proven useful in designing the mold and injection locations for composite parts. To simulate vacuum-assisted resin transfer molding, even though coupled models are successful in predicting flow patterns and thickness distribution, the input requires fabric compaction characterization in addition to permeability characterization. Moreover, due to the coupled nature of flow and fabric compaction, the simulation is computationally expensive precluding the possibility to optimize the flow design for reliable production. In this work, we present an alternative approach to characterize and use an “effective” permeability in the resin transfer molding solver to simulate resin flow in vacuum-assisted resin transfer molding. This decoupled method is very efficient and provides reasonable results. The deviations in mold filling times between experiments and simulations for the resin transfer molding process with E-glass CSM and carbon 5HS were 4.7% and 1.0%, respectively, while for the vacuum-assisted resin transfer molding case using “effective permeability value” with E-glass CSM and carbon 5HS fabrics were 11.1% and 12.3%, respectively, which validates the approach presented.

scholarly journals A Conceptional Approach of Resin-Transfer-Molding to Rosin-Sourced Epoxy Matrix Green Composites

Aerospace ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 5
Author(s):  
Sicong Yu ◽  
Xufeng Zhang ◽  
Xiaoling Liu ◽  
Chris Rudd ◽  
Xiaosu Yi
Keyword(s):  
Composite Laminates ◽  
Resin Transfer Molding ◽  
High Viscosity ◽  
Ramie Fiber ◽  
Liquid Composite Molding ◽  
Curing Agent ◽  
Molding Process ◽  
Transfer Molding ◽  
Low Viscosity ◽  
Composite Molding

In this concept-proof study, a preform-based RTM (Resin Transfer Molding) process is presented that is characterized by first pre-loading the solid curing agent onto the preform, and then injecting the liquid nonreactive resin with an intrinsically low viscosity into the mold to infiltrate and wet the pre-loaded preform. The separation of resin and hardener helped to process inherently high viscosity resins in a convenient way. Rosin-sourced, anhydrite-cured epoxies that would normally be regarded as unsuited to liquid composite molding, were thus processed. Rheological tests revealed that by separating the anhydrite curing agent from a formulated RTM resin system, the remaining epoxy liquid had its flowtime extended. C-scan and glass transition temperature tests showed that the preform pre-loaded with anhydrite was fully infiltrated and wetted by the liquid epoxy, and the two components were diffused and dissolved with each other, and finally, well reacted and cured. Composite laminates made via this approach exhibited roughly comparable quality and mechanical properties with prepreg controls via autoclave or compression molding, respectively. These findings were verified for both carbon and ramie fiber composites.

Development of resin transfer molding process using scaling down strategy

2013 ◽  
Vol 35 (9) ◽  
pp. 1683-1689 ◽  
Author(s):  
Raghu Raja Pandiyan Kuppusamy ◽  
Swati Neogi
Keyword(s):  
Resin Transfer Molding ◽  
Molding Process ◽  
Transfer Molding ◽  
Scaling Down

scholarly journals Resin transfer molding process: a numerical and experimental investigation

2013 ◽  
Vol 7 (2) ◽  
pp. 125-136 ◽  
Author(s):  
Iran de Oliveira ◽  
Sandro Amico ◽  
Jeferson Souza ◽  
Antonio de Lima
Keyword(s):  
Experimental Investigation ◽  
Resin Transfer Molding ◽  
Molding Process ◽  
Transfer Molding

A Closed Form Solution for Flow During the Vacuum Assisted Resin Transfer Molding Process

1999 ◽  
Vol 122 (3) ◽  
pp. 463-475 ◽  
Author(s):  
K-T. Hsiao ◽  
R. Mathur ◽  
S. G. Advani ◽  
J. W. Gillespie, ◽  
B. K. Fink
Keyword(s):  
Closed Form ◽  
Scaling Laws ◽  
Resin Transfer Molding ◽  
Closed Form Solution ◽  
Form Solution ◽  
Flow Front ◽  
Molding Process ◽  
Transfer Molding ◽  
Front Region ◽  
Insight Into

A closed form solution to the flow of resin in vacuum assisted resin transfer molding process (VARTM) has been derived. VARTM is used extensively for affordable manufacturing of large composite structures. During the VARTM process, a highly permeable distribution medium is incorporated into the preform as a surface layer. During infusion, the resin flows preferentially across the surface and simultaneously through the preform giving rise to a complex flow front. The analytical solution presented here provides insight into the scaling laws governing fill times and resin inlet placement as a function of the properties of the preform, distribution media and resin. The formulation assumes that the flow is fully developed and is divided into two regimes: a saturated region with no crossflow and a flow front region where the resin is infiltrating into the preform from the distribution medium. The flow front region moves with a uniform velocity. The law of conservation of mass and Darcy’s Law for flow through porous media are applied in each region. The resulting equations are nondimensionalized and are solved to yield the flow front shape and the development of the saturated region. It is found that the flow front is parabolic in shape and the length of the saturated region is proportional to the square root of the time elapsed. The results thus obtained are compared to data from full scale simulations and an error analysis of the solution was carried out. It was found that the time to fill is determined with a high degree of accuracy while the error in estimating the flow front length, d, increases with a dimensionless parameter ε=K2xxh22/K2yyd2. The solution allows greater insight into the process physics, enables parametric and optimization studies and can reduce the computational cost of full-scale 3-dimensional simulations. A parametric study is conducted to establish the sensitivity of flow front velocity to the distribution media/preform thickness ratio and permeabilities and preform porosity. The results provide insight into the scaling laws for manufacturing of large scale structures by VARTM. [S1087-1357(00)02002-5]

Analysis of the resin transfer molding process using in-mold dielectric sensors

1993 ◽  
Vol 217 ◽  
pp. 251-262 ◽  
Author(s):  
D.J. Melotik ◽  
M. Czaplicki ◽  
T.J. Whalen ◽  
D.R. Day
Keyword(s):  
Resin Transfer Molding ◽  
Molding Process ◽  
Transfer Molding ◽  
Dielectric Sensors
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