Building Big, Printing Smart: Inside Grade2XL’s Vision for Multi-Material Manufacturing

Key information

Project title: Grade2XL
Market: Advanced Manufacturing, Metal Structures

Written by M2i Program Manager: Yulia Fischer

In the world of manufacturing, size usually comes with compromise. Larger components mean longer lead times, heavier material use, and complex logistics. But a pan-European team of researchers and industry players had a different vision: what if we could build big, but smarter? What if we could manufacture high-performance, large-scale metal parts with precision, efficiency, and less environmental impact?

That vision took shape in Grade2XL, a Horizon 2020 project coordinated by M2i. Short for “Application of Functionally Graded Materials to Extra-Large Structures,” Grade2XL explored the full potential of Wire Arc Additive Manufacturing (WAAM) to produce large, complex, multi-material metal components. The results? A leap forward for industrial-scale 3D printing and a blueprint for smarter metal production.

The project tackled one of the most pressing challenges in modern manufacturing: how to make large metal components faster, cleaner, and more adaptable to their function. Using WAAM, the consortium demonstrated that it’s not only possible to print functionally graded, multi-material parts at industrial scale — it’s advantageous.

Across a wide range of use cases, from ship propellers to aerospace tooling, automotive dies to bathtub moulds, Grade2XL delivered eight fully developed demonstrators, each tailored to a specific industrial need. RAMLAB and Naval Group performed process development studies together with the demonstrators’ owners to print their advanced version with WAAM. These weren’t conceptual pieces — they were functional components, often replacing traditionally manufactured parts with better-performing, more sustainable alternatives [Grade2XL_D7.17 Public Report Deliverables].

Take the propeller demonstrator for ship propulsion, developed with MAN Energy Solutions (now Everllence). By combining a strong, corrosion-resistant AM35 inner structure with an erosion-resistant Nickel Alloy 625 outer shell, the team created a part capable of withstanding marine environments with 46% longer lifetime than its conventional counterpart. WAAM also offered flexibility in geometry, leading to a relatively small boost in propulsive efficiency; over time it means significant fuel savings.

In the energy sector, EDF benefited from a WAAM-produced holding ring for hydraulic power plants. By incorporating multiple materials directly during printing — including stainless steel for water contact areas and copper-aluminium alloy for sealing surfaces — the team enhanced corrosion resistance and functionality. More importantly, production time dropped from 36 to 12 weeks, a critical factor in minimizing plant downtime.

Grade2XL also demonstrated that WAAM can improve not just performance, but also sustainability. The Villeroy & Boch bathtub mould saw a 99% CO2 reduction and 97% cost savings. The secret? WAAM-enabled integrated heating channels, faster production cycles, and less material waste. GKN Aerospace, meanwhile, used WAAM to produce a 1.7-meter-long aerospace tooling insert, replacing a 1500 kg billet with just 200 kg of wire. The result: 83% material savings, 77% lower emissions, and a 92% reduction in lead time.

Automotive and tooling industries saw equally strong benefits. Inserts and dies made using WAAM were not only repairable and longer lasting, but also quicker to produce and easier to customize. Gorenje Orodjarna, for example, reported cost savings up to 69% and a dramatic reduction in repair downtime, with some WAAM-produced tools returning to service in just one week.

Behind the impressive numbers lies a bigger story: Grade2XL has proven that large-scale, multi-material WAAM is more than a research curiosity — it’s a viable, often superior alternative to traditional production methods. It enables localized properties, near-net-shape design, and integration of features that would be impossible or prohibitively expensive to achieve otherwise.

Moreover, it opens the door to smarter supply chains. With less dependency on large billets or complex assemblies, WAAM can decentralize production, reduce transport emissions, and enable on-demand manufacturing for critical components.

Of course, not every challenge has been solved. WAAM surfaces still require post-processing, and not all materials are weld-compatible. But the demonstrators offer a playbook for future applications, with clear guidelines for design, material selection, and process integration.

As Grade2XL wrapped up, its legacy is clear. It sets a new benchmark for what additive manufacturing can achieve at scale, particularly in industries where size, performance, and customization matter. The partnership of academia, industrial end-users, and tech developers has shown how European collaboration can translate advanced research into tangible, real-world solutions.

The future? Smarter, faster, greener production. And with WAAM at the center, it’s being printed one layer at a time.

Several of the developments have been submitted to the Innovation Radar by European Commission. Recently, we received information that three of them have been selected for evaluation by the expert jury, and more updates will be published soon.

For more information or to discuss future collaboration, contact M2i, the Materials innovation institute, and visit www.grade2xl.eu

We thank all partners of the project for their contribution to this remarkable achievement.