Grade2XL, next step in Wire Arc Additive Manufacturing (WAAM)

Besides the possibility of producing large workpieces locally with WAAM technology, multi-material printing is also an important unique selling point. WAAM is not limited to one material, but can build workpieces from multiple materials. This offers the possibility of building a large product with only the shell in a more expensive corrosion or wear-resistant material and the core in a cheaper material. To investigate what you could do with all these possibilities on a larger level, WAAM is now being further developed together with 20 partners (including Valk Welding) from all over Europe in the Grade2XL project. With financial support from the EU, WAAM will be further developed over the next 4 years as an economically viable and sustainable alternative to conventional technologies.

For the Grade2XL project, the 3D printing container from Autodesk is now set up at Valk Welding. With 2 welding robots in one system, multi-material parts with new applications such as cooling channels will be printed there. A Cryogenic Cooling and Thermal Management system from Air Products, will also be applied. This will allow to increase further the deposition rate for printing, reduce the idle times for cooling down, provide an inert atmosphere within the working area and thus significantly increase more the productivity and product quality, whilst maintaining ideal thermal conditions.

This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 862017.

A unique collaboration between RAMLAB and Valk Welding

RAMLAB, Europe's first Fieldlab for WAAM Technology, has proven that it can print important parts for industrial applications with WAAM technology, such as the certified ship's propeller of a tugboat from Damen. The initial tests carried out by RAMLAB on Vallourec's behalf led to the contract being awarded to Valk Welding for the construction of the 3D printing cell.

Vincent Wegener, Managing Director of RAMLAB, says: "Our product, MaxQ, consists of a suite of sensors and a software module that we have developed to ensure maximum quality to obtain a certified printed part. The advanced monitoring and control software monitors the process parameters in real time. In addition, the workflow from Autodesk PowerMill CAD files to a program for the Panasonic welding robot is now controlled at the touch of a button. The MaxQ system is fully integrated into the Valk Welding cell. It is precisely in this cooperation that our strength lies and that makes us unique in Europe".

Super Active Wire

Valk Welding has built a cell with 2 workstations, one with a fixed Siegmund table and a second with a five-axis manipulator. Both workstations are equipped for workpieces up to 2 m high, ø 800 mm and a capacity of 500 kg.
In addition, the challenge for Valk Welding was to be able to increase the welding speed without running the risk of damaging the material. For this purpose, a Panasonic welding torch with an integrated servo motor was used, which also supports the Panasonic Super Active Wire process.

In the SAW process, the welding wire moves back and forth at high frequency, allowing more material to be melted per hour with limited heat input.

Proof of concept

"The advantage of the WAAM technology is that only a standard wire is needed as a base material, as opposed to the machining process which requires a specific tool. Regardless of the technology, whether 3D printing or traditional machining, our customers in the oil and gas industry expect a certified product that meets the highest quality standards. Our challenge is to convince them that we can supply their parts that meet these expectations. For this, we count on our pioneering customers who want to be part of this innovation.

The WAAM process parameter optimization that is executed before manufacturing a part, allows for tailoring material properties. In combination with Panasonic’s Super Active Wire Process (SAWP), a stable arc and minimum spatter were achieved. A welding enclosure and extra protective argon (Ar) ensured an inert environment with low level of contaminants.

After the process parameter optimization, the printing was physically scaled up by printing mock-ups for strategy investigation (Figure 1). The experimental phase concluded with manufacturing a solid block (or ‘pre-build’) for tensile
testing in the x-y-z directions. Prior to the mechanical testing, the pre-build underwent solution treatment and ageing.
Figure 2 shows the results of the mechanical testing of the pre-build. A typical anisotropic behaviour is visible in the elongation results. This can be caused by the preferential grain growth induced by the heat source. The overall result shows that the WAAM material has comparable mechanical properties with the 3Dprint AM Ti-5 wire feedstock. Following the mechanical testing, the near-net-shape CAD model was generated by redesigning the original component.
During this operation, additional material was added to allow for the machining of the final net-shape design.

Figure 3 shows the resulting component. Interesting to note the absence of discoloration on the entire part, a sign of a contaminants free environment. During the printing, process parameters were logged using our MaxQ monitoring and
control system for further data analysis. The part was finally sent for final finishing to the net-shape design. Compared to
obtaining the component from a forged block, RAMLAB saved 50% of material and with further improvements it is possible to reach 70% reduction.

With this project RAMLAB showed the potential of the GMAW-WAAM system in printing Ti6Al4V metals parts. We are
collaborating with several institutions to further research this topic. We made a small but important breakthrough in the
GMAW-WAAM of Ti6Al4V parts, getting a step closer for our customers to print Ti6Al4V parts.

Special thanks to our partners: Hittech, AirProducts, Valk Welding, Autodesk, Cavitar, Element, TWI, Voestalpine Böhler Welding and the AMable initiative. If you are interested to learn more about Wire Arc Additive Manufacturing of titanium parts, get in contact.
www.ramlab.com

Figure 3. After milling hal of the part