Laser powder DED additive manufacturing – Producing complex space exhaust lines “right first time”
In the space sector, propulsion components are among the most critical elements of a launcher. Exhaust lines, in particular, must meet demanding requirements in terms of mechanical strength, thermal resistance, geometric precision and material quality. Traditionally produced by assembling rolled and welded sheet metal, these complex methods and processes nonetheless have limitations in terms of manufacturing time, cost and process robustness.
As part of the ENLIGHTEN-ED project, IREPA LASER explored an alternative based on laser powder DED (Direct Energy Deposition) additive manufacturing in order to offer a more integrated and better controlled approach to manufacturing these large components.
Space exhaust lines: between geometric complexity and the limits of assembly-based approaches
Exhaust lines for space applications are large parts, which can reach around 1 m in height and several hundred millimetres in diameter, with variable, complex geometries.
Conventional approaches rely on:
- Rolling of metal sheets,
- Assembly by welding,
- Multiple rework and inspection operations.
These methods involve:
- A large number of manufacturing steps,
- Sensitive welded interfaces,
- Risks of localised defects,
- Long lead times and high costs,
- Increased complexity in guaranteeing repeatability.
Furthermore, controlling distortion and dimensional stability becomes particularly critical on parts of this size, especially when they are subjected to steep thermal gradients and high mechanical stresses.
In this context, the challenge is to reduce reliance on assemblies while guaranteeing a high level of quality right from manufacturing.
Towards more integrated manufacturing with laser powder DED additive manufacturing
To meet these constraints, IREPA LASER implemented an approach based on laser additive manufacturing processes (Laser Metal Deposition), in this case the laser powder DED process, which is particularly well suited to large metal parts.
The aim: to produce more integrated components using a direct manufacturing approach, limiting the need for welding operations.
This approach relies on a complete development chain including:
- The “redesign” of the part taking into account the specific features of the process,
- Thermomechanical simulation to anticipate stresses and distortion,
- The definition of deposition strategies adapted to the different areas of the part,
- The qualification of parameters on representative sub-geometries,
- Step-by-step validation through rapid prototyping of scaled-down parts or critical and sensitive sections of the part
- Dimensional and metallurgical inspections,
- A heat treatment specific to the alloy used (Inconel 625), as recommended by the end customer,
- Non-destructive testing to secure final quality.
This approach treats manufacturing not as mere production, but as a global process controlled from the very first stages.
Anticipating distortion and securing material quality from the development stage
One of the key aspects of the project lies in the ability to anticipate and compensate for the distortion caused by the thermal cycles of the laser DED process.
Thermomechanical simulation tools were used to:
- Predict distortion trends,
- Identify sensitive areas,
- Adjust manufacturing strategies,
- Develop geometric compensation models.
In addition, qualification using sub-geometries made it possible to fine-tune the process parameters according to local variations in the part.
Validation was carried out at several levels:
- Prototypes at reduced scale and then full scale,
- 3D scan inspections to check geometry and feed the modelling and numerical simulation,
- Metallurgical analyses to characterise the material,
- Non-destructive testing to detect any internal defects.
A specific heat treatment, generally proposed by the end customer, may also be considered to control the thermomechanical stresses induced during manufacture of the part
Practical validation on large propulsion parts
This approach made it possible to demonstrate the feasibility of manufacturing complex exhaust lines using laser powder DED additive manufacturing, with:
- A significant reduction in the number of assembly operations,
- Better integration of functions within the part,
- Control of distortion thanks to simulation,
- Validation of the manufacturing strategy on representative prototypes.
The work carried out within ENLIGHTEN-ED also illustrates the ability to produce large Inconel 625 parts with a structured approach combining design, process, modelling and simulation, metallurgy and inspection.
Beyond the technological demonstration, the industrial value lies in the ability to envisage more direct, more flexible and potentially more competitive manufacturing chains for critical components.
Integrated expertise to support the most demanding industrial applications
This type of development highlights IREPA LASER’s expertise in implementing laser processes for complex applications, integrating all the dimensions required for their industrialisation: design, modelling and simulation, manufacturing, treatment and inspection.
In sectors such as space, where reliability and performance requirements are particularly high, laser powder DED additive manufacturing opens up new prospects for rethinking the way large metal components are designed and produced.
Beyond the technical and economic benefits, this approach also helps to strengthen industrial control over the manufacture of critical parts. IREPA LASER thus contributes to strengthening technological autonomy and industrial sovereignty for strategic components, providing controlled solutions from design to manufacturing for all branches of the aerospace sector.
>> To find out more about this work and discover the ENLIGHTEN-ED project, visit its dedicated page.
>> To find out more about our laser additive manufacturing capabilities or to discuss your industrial needs, contact our teams.
The ENLIGHTEN-ED project has received funding from the European Union’s Horizon Europe programme under grant agreement No. 101135156.
