Authored By: SDI Plastics

Through injection moulding the aerospace industry has received a revolutionary manufacturing technology which delivers precise work and operates with efficiency alongside versatile capabilities.

Specialised moulds accept high-performance thermoplastics and composites above molten injection under powerful pressure parameters. Injection moulding drives exceptional benefits to the aerospace industry because it creates lightweight strong components which can replicate complex design shapes.

The aerospace industry advances its goals for fuel efficiency, weight reduction and reliability through injection moulding usage of interior cabin parts along with structural elements and avionics housings. 

By combining various features into one component injection moulding simplifies the assembly process which makes it appropriate for critical system applications. Manufacturers of aircraft systems use injection moulding as their key enabler for sustainable innovation and operational enhancement.

Material advantages in aerospace applications

In aerospace applications, the demand for lightweight yet durable components is paramount, as even marginal weight reductions can significantly enhance fuel efficiency, increase payload capacity, and reduce environmental impact. Injection moulding has emerged as a critical manufacturing method in this sector, enabled by advanced materials like high-performance thermoplastics (PEEK, PEI, PPSU) and composites that uniquely balance strength, thermal resilience, and weight savings. Here’s how these materials excel in aerospace environments:

1. Lightweight

Thermoplastics such as PEEK, PEI, and PPSU are inherently lighter than metals like aluminum or steel, offering a superior strength-to-weight ratio. For example:

• PEEK (Polyether Ether Ketone): Up to 70% lighter than aluminum, yet capable of replacing metal in structural components like brackets, housings, and engine parts.
• PEI (Polyetherimide): Used in cabin interior components (e.g., air ducts, seat frames) due to its low density and flame-retardant properties.
• PPSU (Polyphenylsulfone): Ideal for lightweight, transparent cockpit components requiring optical clarity and impact resistance.

These materials enable complex, thin-walled geometries via injection moulding, further reducing mass without compromising functionality.

2. Durability in extreme conditions

Aerospace components face harsh environments, including rapid temperature shifts, chemical exposure, and mechanical stress. Engineered polymers excel here:

• Thermal stability: PEEK withstands continuous temperatures up to 250°C (482°F), making it suitable for near-engine components. PEI and PPSU retain structural integrity at 170–200°C (338–392°F), critical for avionics and hot-air systems.
• Chemical resistance: Resistant to aviation fuels, hydraulic fluids, and de-icing agents, reducing degradation over time.
• Fatigue resistance: These polymers endure vibration and cyclic loading, crucial for undercarriage components and connectors.

3. Synergy with injection moulding

Injection moulding complements these materials by enabling:

• Precision and complexity: Tight tolerances for aerodynamic or sensor housings.
• Cost efficiency: High-volume production of consistent, net-shape parts (e.g., electrical connectors, ducting).
• Hybrid solutions: Overmoulding composites with thermoplastics to integrate insulation or sealing features.

4. Compliance with aerospace standards

PEEK, PEI, and PPSU meet stringent certifications (e.g., FAA, EASA) for flammability (e.g., FAR 25.853), smoke toxicity, and mechanical performance, ensuring safety in critical applications.

Customisation and composite integration

The customisation capabilities of injection moulding extend beyond material selection to include precise formulation of composite materials. Manufacturers can incorporate various fillers and reinforcements, such as carbon fibre, glass fibres, or mineral additives, to enhance specific properties required for particular aerospace applications.

This allows for the creation of materials with tailored characteristics, including increased stiffness, improved impact resistance, or enhanced electrical conductivity, all while maintaining the processing advantages of injection moulding.

Techniques like overmoulding enable the combination of different materials in a single manufacturing step, proving invaluable in aerospace applications where components require both structural integrity and functional properties, such as vibration damping or electromagnetic interference shielding. 

The integration of these properties directly into the moulded part reduces the need for additional treatments or assemblies, contributing to overall weight reduction and improved reliability.

Consistency and quality control

The consistency and repeatability of material properties achieved through injection moulding align perfectly with the aerospace industry’s stringent quality control requirements. Each batch of material undergoes rigorous testing and certification, ensuring that every component meets the exact specifications required for its intended application. 

This level of material control, combined with the precision of the injection moulding process, results in components that not only meet but often exceed the demanding performance standards of modern aerospace systems.

Precision manufacturing and cost efficiency

Injection moulding delivers exceptional precision and cost efficiency, making it particularly advantageous in aerospace manufacturing. The technology achieves tolerances as tight as ±0.025mm, enabling the production of complex geometries with micron-level accuracy. 

This precision stems from the use of computer-controlled injection systems and highly polished steel moulds manufactured using advanced CNC machining techniques.

Cost advantages

From a cost perspective, injection moulding offers significant economies of scale once the initial tooling investment is made. While the upfront costs for mould development can be substantial, typically ranging from $30,000 to over $250,000 depending on complexity, the per-unit production costs decrease dramatically with higher volumes. For example:

• Large-scale production runs of interior aircraft components can achieve unit costs that are 40–60% lower compared to traditional manufacturing methods like machining or hand lay-up composites.
• The process minimises material waste through its closed-loop system, achieving material utilisation rates exceeding 95%.

Automation and quality assurance

The automated nature of injection moulding reduces labour costs while increasing production speed, with cycle times ranging from 10 to 120 seconds depending on part complexity and material properties. 

Automated monitoring systems track key parameters such as melt temperature, injection pressure, and cooling rates in real-time, ensuring that each part meets specification without requiring individual verification.

This systematic approach to quality assurance not only reduces production costs but also aligns with the aerospace industry’s strict regulatory requirements for documentation and traceability. The combination of precision and cost efficiency extends to quality control measures, reducing the need for extensive post-production inspection.

Weight reduction and environmental impact

Weight reduction is one of the most significant benefits of injection moulding in aerospace. Components made using advanced polymers are 20–50% lighter than traditional metal parts, leading to substantial fuel savings. Every kilogram of weight saved results in approximately 3,000 kilograms of CO₂ emissions reduction annually per aircraft.

Sustainability advantages

The environmental benefits of injection moulding extend beyond fuel efficiency:

• Recyclability: Thermoplastics used in aerospace applications can be recycled without significant degradation, supporting circular economy initiatives.
• Lifecycle sustainability: Eco-design principles, such as designing for disassembly, reduce material waste and promote reuse.
• Regulatory alignment: Injection moulding helps the industry meet net-zero carbon emission targets set by organisations like the International Air Transport Association (IATA).

Design flexibility and innovation

One of the standout features of injection moulding is its design flexibility, which enables engineers to create components that would be difficult or impossible to manufacture using traditional methods. 

The process allows for intricate geometries, undercuts, and thin walls, all within a single moulded part. This capability is particularly valuable in aerospace applications where space constraints and weight considerations are critical.

Rapid prototyping and iteration

Injection moulding also supports rapid prototyping and iterative design processes. Using 3D printing technologies to create prototype moulds, manufacturers can quickly test and refine designs before committing to full-scale production. This accelerates the development cycle and reduces time-to-market for new aerospace innovations.

Multi-functional components

The ability to integrate multiple functions into a single component, such as combining structural support with electrical conductivity or thermal management, reduces the number of parts required in an assembly. This simplification enhances reliability, reduces maintenance needs, and lowers overall system costs.

Conclusion

Injection moulding has revolutionised aerospace manufacturing by delivering lightweight, durable, and cost-effective components that meet the industry’s rigors standards. Its ability to produce complex geometries with precision, combined with the use of advanced materials, makes it indispensable for modern aerospace applications. From enhancing fuel efficiency to supporting sustainability goals, injection moulding continues to drive innovation in the aerospace sector.