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Understanding vacuum bagging layers in production, repair | CompositesWorld

The U.S. Air Force conducted on-base and cross-country mission and performance evaluations of Beta’s composites-intensive CTOL aircraft, hitting key milestones.

Horizontal and vertical tail, aileron, and rudder and elevator will be developed and manufactured for the lift + cruise aircraft, scheduled to enter service in 2026. Fiberglass Biaxial Fabric

Understanding vacuum bagging layers in production, repair | CompositesWorld

In addition to its composite aircraft, Overair will support infrastructure, aircraft operations and training to ensure a comprehensive and sustainable AAM ecosystem.

This initial project under the Space Act Agreement is focused on studying and developing high-performance battery cells, as well as performing safety testing, to achieve purpose-built solutions for electric aircraft.  

AeroZero TPS, applicable for metals and composites, will protect critical battery housing and parts in the Lilium Jet eVTOL aircraft from burn through and risk of thermal runaway.

V-tail, five-passenger aircraft builds on the vison of the S-A1, designed with a priority on safety and a focus on sustainability.

The new alliance will broaden National Composites’ capabilities in SMC and BMC and tooling, while providing customers with comprehensive solutions, from initial design to final delivery.

A new ASTM-standardized test method established in 2022 assesses the compression-loaded damage tolerance of sandwich composites.  

Composites automation specialist increases access to next-gen technologies, including novel AFP systems and unique 3D parts using adaptive molds.

Combined LSAM and five-axis CNC milling capabilities will optimize D-Composites’ production services, flexibility and cut time and cost for composite tooling manufacture.

Evaluation of CFRTP m-pipe through Element’s U.K. facility aims to qualify the system for new operating environments.

Innovative prepreg tooling is highly drapable, capable of forming complex carbon fiber tooling shapes, in addition to reducing through thickness porosity and only requiring one debulk during layup.

Inshore vessel is the largest yet to incorporate the recyclable thermoplastic resin, promotes future sustainability in boat manufacturing.

Projects use Duplicor prepreg panels with highest Euroclass B fire performance without fire retardants for reduced weight, CO2 footprint in sustainable yet affordable roofs, high-rise façades and modular housing.

Available as filament and granules for extrusion, new wood composite matches properties yet is compostable, eliminates microplastics and reduces carbon footprint.

A recent study conducted on vacuum-infused thermoplastic fiber-metal laminates has highlighted the performance benefits behind using TFP’s nonwovens for consistent, uniform bondlines and interfacial bonding.

To incorporate more environmentally conscious practices into its manufacturing processes, VSC is working with Carbon Conversions to reclaim, recycle and reuse its carbon fiber materials.

Switching from prepreg to RTM led to significant time and cost savings for the manufacture of fiberglass struts and complex carbon fiber composite foils that power ORPC’s RivGen systems.

Automated fiber placement develops into more compact, flexible, modular and digitized systems with multi-material and process capabilities.

Available as filament and granules for extrusion, new wood composite matches properties yet is compostable, eliminates microplastics and reduces carbon footprint.

A recent study conducted on vacuum-infused thermoplastic fiber-metal laminates has highlighted the performance benefits behind using TFP’s nonwovens for consistent, uniform bondlines and interfacial bonding.

Switching from prepreg to RTM led to significant time and cost savings for the manufacture of fiberglass struts and complex carbon fiber composite foils that power ORPC’s RivGen systems.

Sara Black’s 2015 report on the development of snap-cure epoxies for automotive manufacturing still resonates today. 

JEC World 2024: Zünd is highlighting digital excellence via its ZCC Cut Center, heat sealing module (HSM), G3 Cutter and ZPC software.

CW explores key composite developments that have shaped how we see and think about the industry today.

Knowing the fundamentals for reading drawings — including master ply tables, ply definition diagrams and more — lays a foundation for proper composite design evaluation.

As battery electric and fuel cell electric vehicles continue to supplant internal combustion engine vehicles, composite materials are quickly finding adoption to offset a variety of challenges, particularly for battery enclosure and fuel cell development.  

Performing regular maintenance of the layup tool for successful sealing and release is required to reduce the risk of part adherence.

Increasingly, prototype and production-ready smart devices featuring thermoplastic composite cases and other components provide lightweight, optimized sustainable alternatives to metal.

The composite pressure vessel market is fast-growing and now dominated by demand for hydrogen storage.

The burgeoning advanced air mobility (AAM) market promises to introduce a new mode of transport for urban and intercity travelers — particularly those who wish to bypass the traffic congestion endemic to the world’s largest cities. The electric vertical take-off and landing (eVTOL) aircraft serving this market, because they depend on battery-powered propulsion, also depend on high-strength, high-performance composite structures produced at volumes heretofore unseen in the aerospace composites industry. This CW Tech Days will feature subject matter experts exploring the materials, tooling and manufacturing challenges of ramping up composites fabrication operations to efficiently meet the demands of a challenging and promising new marketplace.

Manufacturers often struggle with production anomalies that can be traced back to material deviations. These can cause fluctuations in material flow, cooling, and cure according to environmental influences and/or batch-to-batch variations. Today’s competitive environment demands cost-efficient, error-free production using automated production and stable processes. As industries advance new bio-based, faster reacting and increased recycled content materials and faster processes, how can manufacturers quickly establish and maintain quality control? In-mold dielectric sensors paired with data analytics technology enable manufacturers to: Determine glass transition temperature in real time Monitor material deviations such as resin mix ratio, aging, and batch-to-batch variations throughout the process Predict the influence of deviations or material defects during the process See the progression of curing and demold the part when the desired degree of cure, Tg or crystallinity is achieved Document resin mix ratios using snap-cure resins for qualification and certification of RTM parts Successful case histories with real parts illustrate how sensXPERT sensors, machine learning, and material models monitor, predict, and optimize production to compensate for deviations. This Digital Mold technology has enabled manufacturers to reduce scrap by up to 50% and generated energy savings of up to 23%. Agenda: Dealing with the challenge of material deviations and production anomalies How dielectric sensors work with different composite resins, fibers and processes What is required for installation Case histories of in-mold dielectric sensors and data analytics used to monitor resin mixing ratios and predict potential material deviations How this Digital Mold technology has enabled manufacturers to optimize production, and improve quality and reliability

SolvaLite is a family of new fast cure epoxy systems that — combined with Solvay's proprietary Double Diaphragm Forming technology — allows short cycle times and reproducibility. Agenda:  Application Development Center and capabilities Solutions for high-rate manufacturing for automotive Application examples: battery enclosures and body panels

OEMs around the world are looking for smarter materials to forward-think their products by combining high mechanical performance with lightweight design and long-lasting durability. In this webinar, composite experts from Exel Composites explain the benefits of a unique continuous manufacturing process for composites profiles and tubes called pull-winding. Pull-winding makes it possible to manufacture strong, lightweight and extremely thin-walled composite tubes and profiles that meet both demanding mechanical specifications and aesthetic needs. The possibilities for customizing the profile’s features are almost limitless — and because pull-winding is a continuous process, it is well suited for high volume production with consistent quality. Join the webinar to learn why you should consider pull-wound composites for your product. Agenda: Introducing pull-winding, and how it compares to other composite manufacturing technologies like filament winding or pultrusion What are the benefits of pull-winding and how can it achieve thin-walled profiles? Practical examples of product challenges solved by pull-winding

Composite systems consist of two sub-constituents: woven fibers as the reinforcement element and resin as the matrix. The most commonly used fibers are glass and carbon, which can be processed in plane or satin structures to form woven fabrics. Carbon fibers, in particular, are known for their high strength/weight properties. Thermoset resins, such as epoxies and polyurethanes, are used in more demanding applications due to their high physical-mechanical properties. However, composites manufacturers still face the challenge of designing the right cure cycles and repairing out-of-shelf-life parts. To address these issues, Alpha Technologies proposes using the encapsulated sample rheometer (premier ESR) to determine the viscoelastic properties of thermosets. Premier ESR generates repeatable and reproducible analytical data and can measure a broad range of viscosity values, making it ideal for resins such as low viscous uncured prepreg or neat resins as well as highly viscous cured prepregs. During testing, before cure, cure and after cure properties can be detected without removing the material from the test chamber. Moreover, ESR can run a broad range of tests, from isothermal and non-isothermal cures to advanced techniques such as large amplitude oscillatory shear tests. During this webinar, Alpha Technologies will be presenting some of the selected studies that were completed on epoxy prepreg systems utilizing ESR and how it solves many issues in a fast and effective way. It will highlight the advantages of this technique that were proven with the work of several researchers. Moreover, Alpha Technologies will display part of these interesting findings using the correlations between the viscoelastic properties such as G’ and mechanical properties such as short beam shear strength (SBS).

Surface preparation is a critical step in composite structure bonding and plays a major role in determining the final bonding performance. Solvay has developed FusePly, a breakthrough technology that offers the potential to build reliable and robust bonded composite parts through the creation of covalently-bonded structures at bondline interface. FusePly technology meets the manufacturing challenges faced by aircraft builders and industrial bonding users looking for improved performance, buildrates and lightweighting. In this webinar, you will discover FusePly's key benefits as well as processing and data. Agenda: Surface preparation challenges for composite bonding FusePly technology overview Properties and performance data

Venue ONLY ON-SITE @AZL Hub in Aachen Building Part 3B, 4th Floor Campus Boulevard 30 52074 Aachen Time: January 31st, 2024 | 11:00-16:00h (CET) This first constitutive session will shape the future of the workgroup. ✓ Insights into solutions for e.g. circularity, recycling, sustainability, end of life etc. ✓ Interactive exchange along the value chain to tackle these challenges: Share your input in the “World Café” workshop session! ✓ Are you a solution provider? Take your chance and present your solution approach in a short 5-minute pitch. Get in touch with Alexander.  

The Transformative Vertical Flight (TVF) 2024 meeting will take place Feb. 6–8, 2024 in Santa Clara, California, in the heart of Silicon Valley and will feature more than 100 speakers on important progress on vertical takeoff and landing (VTOL) aircraft and technology. 

The EPTA – European Pultrusion Technology Association in cooperation with the American Composites Manufacturers Association (ACMA) invites you to the 17th World Pultrusion Conference which takes place on 29 February – 1 March 2024 in Hamburg, Germany. Visit the most important event in Europe in the market for pultruded fiber reinforced materials  This conference takes place every two years and is the meeting point of the European and worldwide Pultrusion Industry. More than 25 international speakers from Finland, Belgium, Germany, France, Spain, The Netherlands, Turkey, UK, USA, Canada and others will present practical presentations about innovative applications, technologies and processes. Equally current market trends and developments are on the agenda. This World Pultrusion Conference takes place again in the week before the JEC World Composites Show (5-7 March 2024, Paris). The presentation language will be English. Please finde here the full program and booking opportunities. We appreciate very much welcoming you in Hamburg! Inquiries should be requested by email: info@pultruders.com

The Program of this Summit consists of a range of 12 high-level lectures by 14 invited speakers only. Topics are composite related innovations in Automotive & Transport, Space & Aerospace, Advanced Materials, and Process Engineering, as well as Challenging Applications in other markets like Architecture, Construction, Sports, Energy, Marine & more.

JEC World in Paris is the only trade show that unites the global composite industry: an indication of the industry’s commitment to an international platform where users can find a full spectrum of processes, new materials, and composite solutions.

Charting the Skies of Tomorrow: The Sustainable Aviation Revolution Welcome to a new era of air travel where innovation meets sustainability. Electric, hybrid-electric and hydrogen-powered aircraft represent a promising path to reach climate neutrality goals, with the aviation industry and governments jointly pushing boundaries to bring disruptive aircraft into service by 2035. From cutting-edge technologies to revamped regulations and greener airports, the pursuit of sustainable aviation requires unparalleled collaboration throughout the whole aviation value chain and ecosystem. Join us at the Clean Aviation Annual Forum from 5 until 6 March 2024, as we navigate towards cleaner skies together.

Thousands of people visit our Supplier Guide every day to source equipment and materials. Get in front of them with a free company profile.

Jetcam’s latest white paper explores the critical aspects of nesting in composites manufacturing, and strategies to balance material efficiency and kitting speed.

Arris presents mechanical testing results of an Arris-designed natural fiber thermoplastic composite in comparison to similarly produced glass and carbon fiber-based materials.

Cevotec, a tank manufacturer, Roth Composite Machinery and Cikoni, have undertaken a comprehensive project to explore and demonstrate the impact of dome reinforcements using FPP technology for composite tanks.   

Initial demonstration in furniture shows properties two to nine times higher than plywood, OOA molding for uniquely shaped components.

The composite tubes white paper explores some of the considerations for specifying composite tubes, such as mechanical properties, maintenance requirements and more.

Foundational research discusses the current carbon fiber recycling landscape in Utah, and evaluates potential strategies and policies that could enhance this sustainable practice in the region.

To incorporate more environmentally conscious practices into its manufacturing processes, VSC is working with Carbon Conversions to reclaim, recycle and reuse its carbon fiber materials.

As the marine market corrects after the COVID-19 upswing, the emphasis is on decarbonization and sustainability, automation and new forms of mobility offering opportunity for composites.

Novel material to combine Ohoskin’s leather alternative made from orange and cactus byproducts with ReCarbon’s recycled carbon fiber.

The three-year strategic collaboration will help boost the company’s growth, reinforce its commitments to become carbon neutral by 2040 and innovate more circular chemicals and materials.

Oak Ridge National Laboratory's Sustainable Manufacturing Technologies Group helps industrial partners tackle the sustainability challenges presented by fiber-reinforced composite materials.

Eco-friendly carbon fiber slashes carbon footprint by half through renewable energy, a commitment echoed in SGL’s Lavradio biomass plant set to reduce CO2 emissions by 90,000 tons.  

In the Automated Composites Knowledge Center, CGTech brings you vital information about all things automated composites.

This CW Tech Days event will explore the technologies, materials, and strategies that can help composites manufacturers become more sustainable.

Explore the cutting-edge composites industry, as experts delve into the materials, tooling, and manufacturing hurdles of meeting the demands of the promising advanced air mobility (AAM) market. Join us at CW Tech Days to unlock the future of efficient composites fabrication operations.

During CW Tech Days: Thermoplastics for Large Structures, experts explored the materials and processing technologies that are enabling the transition to large-part manufacturing.

Closed mold processes offer many advantages over open molding. This knowledge center details the basics of closed mold methods and the products and tools essential to producing a part correctly.

The composites industry is increasingly recognizing the imperative of sustainability in its operations. As demand for lightweight and durable materials rises across various sectors, such as automotive, aerospace, and construction, there is a growing awareness of the environmental impact associated with traditional composite manufacturing processes.

CompositesWorld’s CW Tech Days: Infrastructure event offers a series of expert presentations on composite materials, processes and applications that should and will be considered for use in the infrastructure and construction markets.

CW’s editors are tracking the latest trends and developments in tooling, from the basics to new developments. This collection, presented by Composites One, features four recent CW stories that detail a range of tooling technologies, processes and materials.

CompositesWorld’s CW Tech Days: Infrastructure event offers a series of expert presentations on composite materials, processes and applications that should and will be considered for use in the infrastructure and construction markets.

Explore the cutting-edge composites industry, as experts delve into the materials, tooling, and manufacturing hurdles of meeting the demands of the promising advanced air mobility (AAM) market. Join us at CW Tech Days to unlock the future of efficient composites fabrication operations.

Thermoplastics for Large Structures, experts explored the materials and processing technologies that are enabling the transition to large-part manufacturing.

Explore the technologies, materials, and strategies that can help composites manufacturers become more sustainable.

A report on the demand for hydrogen as an energy source and the role composites might play in the transport and storage of hydrogen.

This collection features detail the current state of the industry and recent success stories across aerospace, automotive and rail applications.

This collection details the basics, challenges, and future of thermoplastic composites technology, with particular emphasis on their use for commercial aerospace primary structures.

This collection features recent CW stories that detail a range of tooling technologies, processes and materials.

Recognizing the functions of each layer in a vacuum bag schedule can help users discover what vacuum bag schedules work best for their application.

Figure 1. Vacuum bag schedule. This illustration shows a number of different layers/functions that can be deployed within a vacuum bag for processing a composite laminate. This type of arrangement might be applicable to a vacuum bag only (VBO) type process but in no way is it universal to all applications. Photo Credit, all images: Abaris Training Resources

The advanced composites manufacturing industry uses more vacuum bagging materials than they do almost any other consumable product. There are numerous materials specified for use under the vacuum bag film itself. Each layer provides a different function necessary to a specific method of processing — for example, vacuum bag only (VBO), in or out of an oven, autoclave, vacuum infusion and more — not to mention multiple vacuum compaction (debulk) operations that might be prescribed for a given layup. The materials must be capable of surviving the process (cure) temperature without degrading. Exploring these materials and their functions in more detail can help users better understand vacuum bagging schedules used in production and repair.

The vacuum bag schedule is made up of a series of materials that provide a variety of services: bagside release from the laminate, resin bleed, resin filtering or blocking, breathing (allowing gas to escape during processing) and maintenance of continuous atmospheric differential pressure on the laminate (Fig. 1). The descriptions of each function along with common materials are discussed as follows.

The release layer is a material that can be removed from the backside of the laminate after processing, therefore preventing the other layers from sticking to it. A fabric peel ply or a release film is typically prescribed for this purpose. The type of material specified depends on whether the intent is to stop, filter or allow resin to flow through this layer and what surface texture is desired. Dry peel ply and fiberglass fabric coated with polytetrafluoroethylene (PTFE) are materials commonly deployed at this level.

Dry peel ply is a porous nylon or polyester fabric that enables resin and gas to flow into or through the layer. It is multifunctional in this application as it can provide release from the laminate and move/absorb resin during processing. There are many types of dry peel ply, ranging from lightweight and finely woven to heavy-duty (coarse) fabrics that leave a corresponding texture on the backside surface of the laminate. (Note: a “wet” or prepreg peel ply might be prescribed for this function but would be called out in the layup schedule for the laminate and not in the bagging schedule.) Once the peel ply is removed from the laminate, the resulting surface may be suitable for painting or bonding, depending upon the materials used and the texture that remains.

PTFE-coated fiberglass fabric can also be used as a peel ply layer. There are two versions designated as either Teflon fabric porous (TFP) or Teflon fabric non-porous (TFNP). The TFP version allows resin and gas to flow through the layer, but it does not necessarily absorb resin in the same manner as dry peel ply. The TFNP blocks resin flow into or through the layer, but it is permeable to some gases under pressure. With both of these fabrics, the resulting surface is unsuitable for bonding due to the low surface free energy created by the TFP/TFNP contacting this surface (few available polar arrangements to attract wetting).

Release film is another option for material at this level — a solid film is prescribed to block all resin movement, and a perforated film allows resin movement. These can be made from polymethyl pentene (PMP), polyethylene terephthalate (PET), fluorinated ethylene propylene (FEP), polyolefin or other polymers. These films leave a glossy, low energy surface on the backside of the laminate, which is also unsuitable for bonding.

The filter layer is designed to allow a regulated amount of resin and gas to pass from an underlying layer (or laminate) to the next layer above. The material is a perforated version of the above-mentioned release film with a pierced puncture (flap, no hole) pattern or either 0.015- or 0.045-inch-diameter holes — available with hole spacing between 0.25 to 10.00 inches apart, staggered or on-center. These materials are available as off-the-shelf products1 with common perforation style designations (for example, P, P2, P3, etc. per Table 1) or the user can self-perforate solid release film to any pattern and hole size they desire. In addition to inter-schedule use, perforated film is typically used as the release layer against the laminate when performing debulk operations. A filter layer is not necessary if the prior layer is non-porous.

Table 1. Perforation styles table. A partial list of perforation styles that are available from various vacuum bag material suppliers.

The bleeder layer is just that — a layer (or layers) of absorbent material that will determine the volume of resin that can be “bled” directly from a previous layer or as regulated through a filter layer. The bleeder layer is generally used in out-of-autoclave (OOA) processes to allow resin and gas movement from the laminate into the breather system (see “Breather layer” below). Bleeder materials range from fine-woven glass fabric to nonwoven polyester (“baby blanket”) material. The fine-woven glass leaves a uniform texture on the backside of the laminate — the nonwoven polyester material leaves a more irregular surface. This may be a consideration for areas that have surface profile or roughness tolerances, or for aerodynamic composite repairs.

The separator layer is designed to stop resin from flowing from one layer to the next. It is typically used between the bleeder layer and the breather layer, but it can also be used as a release layer between the laminate and the breather in a bag schedule designed for autoclave processing, as depicted in Fig. 2. Typically, a solid release film is used for this purpose. However, any material that stops resin flow can be used as a separator — for example, TFNP or bagging film. The latter should not be directly against the laminate unless it is made from a low-energy, release-capable polymer. (See “Vacuum bag membrane” below.)

Figure 2. Vacuum bag schedule for autoclave. Fewer materials are necessary for autoclave processing, as the need to move resin and gas can be accomplished at higher pressures without a bleeder system.

The function of the breather layer is two-fold. First, it acts as a continuous path under the bag membrane to enable differential atmospheric pressure to be equally distributed across the part area. Second, it is the route for volatiles and other gases to escape from the arrangement under the bag through the vacuum ports and hoses into the vacuum system and eventually to the atmosphere.

The materials used for the breather are like those used for the bleeder but often have more bulk so that they do not seal off under pressure. Ten to 18 ounce per square yard (339-610 grams per square meter) nonwoven polyester materials are common for up to 100 psi (6.9 bar). For higher pressures (or temperatures), heavy glass fabric might be specified to meet the process requirements. Premium nonwoven, blended fiberglass breather is available for ultrahigh temperature and pressure use. This material also may be better suited as a breather layer over complex geometries, where a glass fabric may be prone to bridging.

The vacuum bag membrane is a pliable, nonpermeable film layer used to separate the interior of the bag from the outside environment — providing differential clamping pressure on the laminate during processing. The film material is selected based upon the upper temperature it will see and the durability required to survive the process. Increased bag thickness improves durability but at the risk of losing malleability. Materials range from polyolefin to nylon to polyimide to thermoplastic elastomers and other hybrid formulas, each having different thermal properties and performance characteristics.

While there is much more to learn about vacuum bagging, understanding the function of each layer can help users better analyze their needs and, therefore, design vacuum bag schedules that work the best for their specific applications (Fig. 3). This task is often left to material and process engineering in the larger companies, but it applies to everyone who needs insight into the functionality of the bag schedule as a system.

Figure 3. Bag schedule for composite repair. An example of a bag schedule used for composite repair. (1) The resin bleed is visible on one panel just under the bag. (2) A top view of the bleeder schedule after processing and after removal of the bag. (3) The schedule layers consist of a TFP peel ply release layer, a #1581 style glass fabric bleeder, a P3 perforated film filter layer, another #1581 style glass fabric bleeder layer and a solid film separator layer. These were all under a breather layer, inside the bag.

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Approaching rollout and first flight, the 787 relies on innovations in composite materials and processes to hit its targets

Automated preforming and 5-min resin infiltration show a way forward for lower-cost CFRP primary structures.

From multifunctional aircraft interiors to compounds using continuous fabrics to the growing use of recycled carbon fiber – compression molding offers new opportunities.

This is the fifth in a series of Tech Tables and comprises vacuum bagging material data provided by suppliers.  

The combination of material state management (MSM) software and an encapsulated sample rheometer (ESR) enables real-time cure recipe management or cure model development inside the autoclave.

Composites are used widely in oil/gas, wind and other renewable energy applications. Despite market challenges, growth potential and innovation for composites continue.

Understanding vacuum bagging layers in production, repair | CompositesWorld

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