Developing large-scale INVAR® tools without the need for foundry

The industrial challenges of the ARWEN Project

The project is part of a context of increasing industrial production rates and the growing use of composite materials in aeronautics. Tooling made by foundries can generate non-quality, long lead times and high costs.

• to propose an alternative to the foundry process;
• avoid non-quality issues associated with raw mussels;
• reduce manufacturing and procurement times.
• reduce the cost of tools;
• increase the supply possibilities of INVAR® tooling;
• enable the modification or repair of tooling by additive manufacturing.

ARWEN thus aims to secure the availability of large-scale tools while bringing back some of the added value at Loiretech.

Technologies developed for invar tooling

The project developed and validated several technological building blocks necessary for the realization of the hybrid process:

• a discretization algorithm to determine the blocks constituting the surface of the tooling;
• optimization tools coupled with welding modeling software to minimize deformation;
• coupling with the discretization algorithm in order to minimize the cost under business constraints;
• robotic strategies for paver positioning, welding and additive manufacturing trajectories;
• welding and additive manufacturing process parameters;
• the strengthening of skills in robotic welding, WAAM additive manufacturing, optimization and understanding of the physical phenomena related to the MAG process;
• the acquisition of a WAAM robotic welding and additive manufacturing cell.

The work led to the validation of generic bricks on several paving stones, to the creation of a representative "angle" demonstrator and then a "1 m² shell" demonstrator.

Project results and industrial impacts

The results of the project are presented as very encouraging and offer an improved alternative to the foundry for the production of tool blanks.

• improvement in the quality of the crude oil produced, with a sharp reduction in rework times due to non-quality;
• a five-fold reduction in manufacturing and supply time;
• lower manufacturing cost;
• provision of a scale 1 industrial facility at Loiretech;
• possibility of modifying or repairing tooling by additive manufacturing;
• re-internalization of added value at Loiretech by limiting subcontracting to foundries.

At the end of the project, the accurate assessment of the economic impact was still considered premature, but the quality and time gains were already established.