When we talk about aerospace and additive manufacturing, it is easy to think of futuristic-looking 3D printed metal engine components, but there is also another rapidly growing and highly beneficial application area that is transforming aerospace production for the better: 3D printed composite tooling. Airtech Advanced Materials Group, which has over 50 years of experience with vacuum bagging and composite tooling materials, has become a key leader in this evolving segment, leveraging large-format additive manufacturing (LFAM) and its industry-leading materials to rapidly produce composite tooling products, like autoclave molds, fixtures, master models, and layup molds, for industries including aerospace.

Aerospace has been an important segment for Airtech since the company’s inception: when it started, Airtech’s mandate was to supply aerospace manufacturers with composite auxiliary products and tooling materials. Today, this relationship remains strong, as aerospace OEMs have now also become keen adopters of Airtech’s 3D printed composite tooling. “The aerospace market segment represents a significant proportion of Airtech’s global business in both its composite auxiliary materials businesses as well as additive manufacturing,” said Gregory Haye, Director of Additive Manufacturing at Airtech.

Airtech’s additive manufacturing offering includes the Print-Tech in-house printing service capabilities, a hybrid process that combines large-format thermoplastic extrusion 3D printing (with dimensions up to 12 x 3 meters) and precision machining to achieve robust and dimensionally accurate tools for producing composite aerospace components. This process for composite toolmaking has many advantages for aerospace OEMs, including dramatically reducing lead times and the costs associated with traditional tooling sourcing.

As Gregory Haye explains: “OEMs are under increased pressure to always reduce lead time and cost.  Fortunately, these are common benefits of implementing LFAM processes in tooling and components.” However, the 3D printing process itself is only part of the equation. Arguably more fundamental to Airtech’s prominent role in the aerospace industry are its Dahltram tooling resins reinforced with glass or carbon fibers.

Aerospace-ready materials

Within its materials range, Dahltram I-350CF has emerged as the most popular in the aerospace industry. This material, a modified PEI-based plastic with carbon fiber reinforcement, can withstand temperatures up to 212°C and is thus suitable for high-temperature applications like hot forming tools, autoclave molds, oven molds, and more. In addition to Airtech’s in-house printing equipment from Thermwood and CEAD, the material is also compatible with several other large-format AM platforms.

Last year, we covered an important milestone for Airtech and its Dahltram I-350CF material, as it successfully underwent over 500 autoclave cycles of 176°C and 100 psi (7 bar) without signs of failure. This testing, which was carried out at Airtech’s facility in Huntington Beach, California, has been a key step in showcasing the material’s viability not only for prototyping or small-batch production, but also larger production runs that require autoclave testing.

“Our Dahltram I-350CF has seen the widest use in aerospace programs to date,” Haye says. “Airtech invested early in being able to address the risk points associated with LFAM or FDM printing by testing producing printed specimens and full finished tools and subjecting them to the workshop and processing conditions consistent with OEM aerospace commercial standards. Our recently published autoclave cycle report walks through the full lifecycle of 500 uses in a 180°C/350°F curing tool proving the tool can maintain aerospace accuracy and vacuum integrity with our materials. This level of detail and data has supported our successful use and sale of this material to customers globally.”

He continues to explain how Airtech’s solutions meet the stringent requirements of aerospace production while also improving their production workflows: “Mold longevity and vacuum integrity in curing tools are always high on the list of concerns when first reviewing the technology. Airtech has made it a point to address the typical questions or concerns raised by OEMs and their suppliers by producing validation molds or samples and testing them in production conditions such as high-temperature ovens and autoclaves.

“We also perform extensive contact materials testing with various chemicals, sealers, cleaners, and thermoset composite resin systems. By being able to address these key technical areas by utilizing our in-house printing capabilities alongside our global technical resources over the past few years Airtech has been able to reduce or eliminate initial validation phases for many potential customers resulting in a quicker first physical project and an eventual qualification for commercial use.”

Applications with greater circularity

There are a number of different tooling applications that Airtech’s Dahtram material range is suitable for in an aerospace context, including autoclave tooling, infusion tooling, jigs and fixture tooling, oven molds, and custom tooling. According to Gregory Haye, these have all been of keen interest to aerospace OEMs, who are turning to different materials in the Dahtram portfolio depending on the application at hand (for example, the company’s Dahltram S-150CF resin is suited for low-temperature applications like holding fixtures and trim tools).

“We have seen a uniform adoption across all applications in composite tooling over the last five years,” he says. “Some customers have recognized the low hanging fruit of room temperature applications while others have relentlessly pursued high-temperature curing tools due to possible large payback on lead time and cost savings shown.”

In the latter category, we can turn to British aerospace multinational BAE Systems, which has used Airtech’s Dahltram I-350CF resin and LFAM to develop high-temperature mold tooling for the Combat Air environment. By combining Airtech’s tooling material with Ingersoll Machine Tools’ MasterPrint LFAM system, the company was able to exploit the benefits of 3D printed tooling, including reduced lead times, a more streamlined workflow, and lower costs.

Another significant benefit for the aerospace group was minimized material waste: not only does the additive process itself reduce material waste compared to a purely subtractive process, Dahltram I-350CF and all of Airtech’s resins are fully recyclable. Ultimately, this enables aerospace manufacturers to achieve greater circularity when it comes to their mold and tooling production.

Swedish aerospace company SAAB also turned to Airtech’s composite tooling resins and large-format 3D printing to enhance the sustainability of its production. In this case, the company worked in cooperation with Airtech and Ai Build to develop a mold for the Clean Sky 2 initiative, a European research program dedicated to developing technologies that reduce CO2 emissions associated with aviation. The collaborative project, which was completed in 2022, was focused on improving the sustainability of producing a cargo door mold. This was achieved using Dahltram I-350CF and Ai Build’s industrial 3D printing solution. The mold, which measured over two meters, was able to withstand the necessary temperatures without leakages and thanks to the large-scale AM process could be made in a single piece, minimizing assembly steps. On top of that, the use of the carbon fiber-reinforced plastic resulted in a much cheaper and more lightweight tool compared to the original metal tool.

The future for Airtech in aerospace

Airtech’s materials and its Print-Tech services are today creating many opportunities for aerospace companies to accelerate and improve prototyping and production processes for end-use parts. In the future, these opportunities will only grow, as Airtech and its partners are continually innovating and developing new solutions and application areas.

You don’t have to look further than the EmpowerAX project for proof. The project, which won the JEC 2024 Innovation Award for Aerospace Processes, is a collaborative endeavor spearheaded by DLR and 12 international partners: Airtech, CEAD, 9T Labs, Ansys, Siemens, Ensinger, Fiberthree, Fill Gesellschaft, WEBER additive, PRIME aerostructures, Suprem and SWMS Systemtechnik Ingenieur. The project aims to develop an accessible process for additive extrusion with continuous fiber reinforcement.

The partners recently demonstrated a process chain for printing local reinforcement on an existing multi-curved thermoset shell. The project involved the robotic extrusion of Dahltram I-350CF resin onto a conventionally produced aerospace shell to optimize the part’s stiffness in specific areas without significantly adding weight.

“While the industry and Airtech have been focused on tooling for aerospace we see a clear trend of interest to produce LFAM size parts or hybrid components in various applications in aerospace,” Haye elaborates. “EmpowerAX was a great first step and proving point that will help facilitate further larger and more complex applications and allow the ecosystem to refine their offerings to be deployable to commercial applications.”

Ultimately, for Airtech, the future of AM in aerospace is about innovating and making processes more efficient and sustainable.

This article was originally published in VoxelMatters’ VM Focus Aerospace eBook. Read or download the full eBook for free at this link.