Liquid Composite Molding control methodologies using Vacuum Induced Preform Relaxation

Alms, Justin B.; Advani, Suresh G.; Glancey, James L.

doi:10.1016/j.compositesa.2010.10.002

Cited by 36 publications

(24 citation statements)

References 11 publications

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“…As the vent is located on top of the membrane, no resin can bleed out of the part during post-filling, it is therefore crucial to carefully control the amount of resin injected during the filling phase in order to maintain a consistent high fibre volume fraction. The vacuum induced preform relaxation (VIPR) 12,13 process uses a mobile vacuum chamber placed on top of the vacuum bag to locally reduce preform compaction and thus locally increase permeability. The primary goal of the VIPR process is to increase control on the progression of the flow front.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation into the post-filling stage of the resin infusion process

Govignon

Bickerton

Kelly

2012

Journal of Composite Materials

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The resin infusion process has developed as a low-cost method to produce large composite parts in low to medium quantities. Although the process is conceptually simple, the effects of many of the processing parameters on the postfilling stage of the process are not well understood. Most manufacturers tend to develop their approach to infusion process through trial and error, and then adhere to their 'secret recipe' without knowledge of the effect of each parameter. This paper describes an experimental investigation of the controllable process parameters and their effect on the final laminate composition, by monitoring local fluid pressure and full field laminate thickness data through the filling and post-filling stages. From the understanding of the effect of each parameter, guidelines are drawn to help manufacturers to optimise their process. The effect of using a 'brake' between the part and the vent are evaluated, and the benefits of turning the inlet into a vent at the onset of post-filling are highlighted together with methods of gaining some control on the final laminate fibre volume fraction.

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Section: Introductionmentioning

confidence: 99%

Experimental investigation into the post-filling stage of the resin infusion process

Govignon

Bickerton

Kelly

2012

Journal of Composite Materials

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“…Also these tools can be readily implemented with RTM as one can direct the resin flow by introducing more injection gates and locally changing the pressure field. This is more difficult to implement in VARTM [28,29]. Hsiao et al proposed use of distribution media, which is more appropriate for VARTM processing, as a flow control tool and the race-tracking possibility is handled by placing flow channels [19].…”

Section: Introductionmentioning

confidence: 98%

A methodology to reduce variability during vacuum infusion with optimized design of distribution media

Şaş

Šimáček

Advani

2015

Composites Part A: Applied Science and Manufacturing

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a b s t r a c t Seemann Composites Resin Infusion Molding Process (SCRIMP) is a widely used version of VacuumAssisted Resin Transfer Molding (VARTM) in which a highly permeable layer (distribution media) is placed on top of the dry preform to distribute the resin with very low flow resistance to reduce the filling and hence the manufacturing time. The flow patterns during filling may vary from part to part due to the variability associated with the material, part geometry, and layup of the assembly, which may result in race-tracking channels. The process is considered as reliable and robust only if the resin completely saturates the preform despite changing filling patterns caused by flow disturbances.The resin flow pattern can be manipulated with a tailored distribution media layout as it does impact the flow patterns significantly. The continuous distribution media layout over the entire part surface works well for very simple geometries with no to little potential for race-tracking along the edges. In this study we address complex cases, which require placement of an insert within the assembly, which will introduce race-tracking along its edges, and hence uniform placement of distribution media over the entire top surface will fail to yield a void free part. We introduce a methodology using a predictive tool to design an optimal shape of distribution media, which accounts for the flow variability introduced due to race-tracking along the edges of the inserts. This iterative approach quickly converges to provide the placement of distribution media on selective areas of the preform surface that ensures complete filling of the preform despite the variability. This approach has been validated with an experimental example and will help mitigate risk involved in manufacturing complex composites components with Liquid Molding.

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“…The active control in this system depended on reducing the viscosity and increasing the permeability at certain locations by locally heating resin. Another method called Vacuum Induced Preform Relaxation (VIPR) that relied on local flow condition changes was presented by Alms et al . This method used an extra vacuum chamber to locally reduce the compaction pressure on fibers and tried to increase the permeability of fibers in that region.…”

Section: Introductionmentioning

confidence: 99%

Automation of the vacuum assisted resin transfer molding process for recreational composite yachts

et al. 2015

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The use of glass fiber reinforced plastics (GFRP) in large primary marine structures has noticeably increased due to their favorable stiffness, strength, durability, and manufacturability. However, GFRP construction can become cost‐prohibitive at the superyacht‐scale (36–60 m) as defects and labor intensiveness increase. In this paper, we presented an automated vacuum assisted resin transfer molding process (VaRTM) that can be integrated into an existing setup for manufacturing recreational composite yachts in the 49‐meter range. The objective of automating the system is to reduce defects and labor intensity. The developed automation system consisted of a controller, resin supply lines with valves, and infrared sensors. The control software, valves and sensors were custom developed. The system automatically monitors and adjusts resin flow in the mold in real‐time to mitigate flow front variations. The system was used to run three different scenarios common in marine composites manufacturing using VaRTM; a flat plate with consistent ply sequence, a flat plate with varying ply sequence, and a scaled yacht keel section. Results indicated that use of the automated setup improved overall evenness of resin flow and limited unwanted convergence compared to the traditional manual setup. Tensile testing indicated similar mechanical performance but greater variation in the manual sample. Voids were discovered in regions of flow convergence of the manual panel and reflected slightly more varied tensile properties as compared to automated panels. POLYM. COMPOS., 38:2411–2424, 2017. © 2015 Society of Plastics Engineers

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Liquid Composite Molding control methodologies using Vacuum Induced Preform Relaxation

Cited by 36 publications

References 11 publications

Experimental investigation into the post-filling stage of the resin infusion process

Experimental investigation into the post-filling stage of the resin infusion process

A methodology to reduce variability during vacuum infusion with optimized design of distribution media

Automation of the vacuum assisted resin transfer molding process for recreational composite yachts

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