What if RTM could keep up with future aerospace production rates — without multiplying molds, ovens, and complexity?

Key takeaways:

1. Fast Cure RTM can be demonstrated on a real production part, using production preforms and tooling.
2. Very short injection times and 15‑ to 30‑minute polymerization at 180 °C provide a key enabler for accelerating cycles.
3. At this stage, machining, ultrasonic inspection and geometric conformity are equivalent to the reference process within the scope of this demonstration.
4. Projections show a potentially major impact on equipment needs and production lead times, subject to qualification and confirmation of material characterization results.

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In aerospace, increasing production rates without compromising industrial robustness is one of the major challenges facing the composites industry. It is a strategic issue, as it involves both supporting the current ramp‑up and preparing for the arrival of next‑generation short‑ and medium‑range aircraft, known as SMR (Short Medium Range).

This is precisely the objective of our work at Daher: accelerating certain composite manufacturing processes without compromising the robustness of the industrial flow. While our investments and progress in thermoplastics are well known, Daher also relies on other technological drivers – such as the recent tour de force (impressive accomplishment) achieved with the RTM process.

RTM, for Resin Transfer Molding, is based on a principle that is simple to define but demanding to implement: a resin is injected into a closed mold containing a fiber preform. The resin then polymerizes to form the final part. Industrial performance depends on the precise control of each of these steps.

Two years ago, I shared an initial R&T demonstration carried out on a prototype part called a “gutter”, injected using Fast Cure resins. It was a very promising proof of concept, but it remained at the research project stage.
(See: LinkedIn post)

For the next step, our goal was different: to carry out a demonstration on a production part, using production preforms and – most importantly – the production tooling used on a commercial program, and then to objectively measure the differences – or the absence of differences – compared with the “standard” RTM resin currently qualified on aircraft.

Objective: Demonstrate feasibility on an actual production part

The selected part is anything but a laboratory test piece. It is a composite nacelle frame, a structural component of the air inlet. In other words, a large‑scale, fully functional part, directly representative of the constraints of serial aerospace production.

At Daher, this part is manufactured at our Saint‑Aignan‑de‑Grandlieu site and then integrated directly into the air inlet at the customer’s facility.

Why this part?

Because it brings together characteristics that are highly representative of a real industrial challenge.

• Geometry: a quarter circle with a 3,050 mm diameter, approximately 35 mm high, 40 mm wide, and 2 mm thick.
• Material architecture: a carbon fiber preform combining woven fabrics and unidirectional plies, incorporating a wire‑mesh metallization – a thin metallic grid intended, among other functions, to provide lightning strike protection.

Our objective was clear: demonstrate feasibility on a production part, while estimating the potential cycle‑time reduction for the injection + polymerization phase. We also sought to assess the impact of these new materials on downstream operations – machining, non‑destructive inspection, and dimensional inspection – to anticipate their effects on the overall industrial flow.

Method: production means, two Fast Cure resins, short cycles

At the end of 2025, we deliberately removed production preforms and production injection tooling from the production flow.

The trials were carried out using two Fast Cure resins developed by Hexcel:

• HiFlow HF640F‑2, with a 15‑minute polymerization time, and
• HiFlow HF610F‑2, with a 30‑minute polymerization time.

The term cure refers to the phase during which the polymers contained in the resin organize themselves to confer the material’s mechanical and thermal properties. The difference between these two grades is therefore not limited to curing time alone: it also affects the injection window, that is, the period during which the resin remains injectable under controlled conditions.

The key point is that these resins allow isothermal injection at 180 °C, followed directly by a short polymerization of 15 or 30 minutes. Most importantly, they enable hot demolding, which facilitates rapid sequencing of operations and, ultimately, higher production rates.

By combining the expertise of Hexcel and Daher, we manufactured six “production‑type” parts (non‑airworthy): five using HF640 resin and one using HF610.

The observed results are particularly encouraging:

• Injection time below two minutes,
• Rapid polymerization, and
• Demolding performed as early as possible, as the production tooling is not designed for hot demolding.

Finally – and this was essential – the demonstrator parts were reintegrated into the plant’s serial production flow to follow the standard downstream process, allowing step‑by‑step comparison with parts manufactured using the reference process.

Results: Production conformity and −75% cycle‑time reduction

First good news: no noticeable difference in machining compared with parts produced using the reference process.

From a non‑destructive inspection standpoint, ultrasonic testing delivered equivalent results, within approximately −0.5 dB.

And, for what often is the most unforgiving criterion in series production – is dimensional conformity – there was no difference. The parts were geometrically compliant.

Overall, compared with the reference serial process (injection followed by polymerization), this demonstration indicates a cycle‑time reduction of around 75% on the core of the process, without modifying upstream or downstream operations.

Production‑rate projections

At this stage, these resins are not yet qualified. However, the demonstration already makes it possible to establish industrial orders of magnitude and to highlight a key point: the higher the production rate, the more structuring the gap becomes between a standard RTM cycle and a Fast Cure cycle.

Scenario 1: Industrial rate on a serial program
With a standard process, achieving the required rate generally means multiplying resources – several molds and additional heating equipment. This configuration will become unavoidable as production rates reach their maximum.
Conversely, with a Fast Cure process, tooling requirements could be divided by eight. A single piece of equipment, such as a mini‑press, would be sufficient, with the added flexibility of being able to allocate it to other aircraft programs. In this scenario, series production could be completed in eight days, compared with 19 days using the standard process at full rate.

Scenario 2: Very high rates (for future large aircraft program)
At very high rates, the difference changes scale. The standard process leads to a significant need for tooling (more than 30 molds) and equipment (five ovens). Fast Cure resins, on the other hand, could drastically reduce this requirement, with only two molds and two mini‑presses for polymerization.
This represents a shift from a strategy of multiplying resources to one focused on accelerating the cycle. In other words, it becomes possible to process thermosets like thermoplastics – which happens to be the specialty of our Saint‑Aignan site.
These projections naturally remain subject to full qualification by the final aircraft manufacturer, as well as confirmation that performance levels are maintained across all aerospace requirements.

What about material performance?

We did not limit ourselves to evaluating the process alone. In parallel, we produced qualification test specimens, referred to in our terminology as First Part Qualification, to characterize the mechanical behavior of the parts. Results are expected by the end of June, and the initial indicators are very promising.

 

 

📍 To learn more, meet us at JEC World (Hall 6 – Stand G62),  10-12 March 2026

A team effort

This demonstration was conducted as part of the DISPRO project, in partnership with Airbus and with the support of the French DGAC civil aviation authority.The Daher team (Anthony Méresse, Camille George, Steven Araujo, Quentin Philippe, Samuel Richard) is evaluating these next‑generation resins, which offer notable promises: higher service temperature (Tg), improved mechanical performance, and broader application potential.

Special thanks also to the Daher Nantes teams (Gregory Coin, Thierry Guillaume, Steven Vallade, Alexandre Sanchez, Fabien Trichet) who made this ambitious demonstration possible. And of course, to our partner Hexcel (Carolina Brantes, Jean Pourtier, Joanna Baudino, Alexis Bart, Pauline De Cuttoli) for the injections.