Project goals and objectives

The main project’s objective is to develop the production technology of components such as water turbine propellers, seawater pump elements (impellers, manifolds) and valves using newly developed Cubased alloys by means of 3DMP® technology, which is one of the most innovative technologies of the Wire Arc Additive Manufacturing (WAAM) processes. Importance of WAAM:

• Both in terms of equipment cost (CAPEX) as well as feedstock cost (OPEX), WAAM represents the technology with the lowest investment needs. As compared to powder bed technologies which require tailormade printers (often operating under protective gas or vacuum conditions), WAAM technology uses offtheshelf available welding sources and robots. As illustrated by the data in Table 1, the wire feedstock costs for WAAM are significantly lower compared to its powder counterparts. The importance of feedstock cost is clearly illustrated by Fig. 1 which shows that powder prices will need to be brought down drastically in order to reach a profitable business case.
• As compared to competing technologies (Fig. 2), WAAM furthermore exhibits significantly higher deposition rates which can go up to 10 kg/h for a single deposition source. Moreover, one could easily imagine to operate several sources simultaneously to increase this number even further.
• WAAM imposes less severe restrictions on the required labour skills as its constituent components (welding source and robot) are widespread and trained globally, making it also the most robust technology.
• Reduced accuracy: as opposed to the electronics or medical industries where geometry accuracy down to μm range is often required, far less severe restrictions hold in our target sectors. In addition, in today’s reference manufacturing processes postmachining is also often required in specific areas.
• Reduced complexity: although the level of complexity which can be achieved with WAAM is lower as compared to powder bed technologies, the WAAM process will mostly be benchmarked against cast or mechanically assembled components in our target sectors. In that scenario, WAAM will still allow for higher levels of design freedom as compared to today’s practice (Fig. 3).

Within the framework of this project the parameters of the technological processes allowing to produce aforementioned components using wires made of Cu alloys as the input material will be optimized, using knowledge and expertise already available in the consortium. The technological solutions developed in this project will be novel in comparison with the current solutions based on the conventional metal processing technologies. Importantly, the new components printed with the Cu alloy wires can be reused after being melted and refined, which is consistent with the KIC 3 strategic goal, i.e. „closing material loops”.

The production technologies proposed within this project can use scrap as a material for the production of the wires and do not generate wastes. The main advantages of the solution is using wires as the input material instead of metal powders, which is way more suitable to generate low to medium complexity and medium to large scale components. Presently, in the WAAM processes, mainly wires made of steel, aluminium and titanium are used. This project is aimed at developing new wires made of Cu based alloys. The scope of work of this project covers all crucial stages for application of the new Cu based wires in the 3DMP® production process at the industrial scale. The project envisages also the influence of the 3DMP® process on the resulting mechanical properties of the Cu based alloys. Thus, realization of the planned research will contribute to extending the knowledge concerning the chemical compositions of the Cubased alloys intended to be used in the additive manufacturing processes. This will expand the impact of this project, because that knowledge together with new technology can be used in the development of other products for different applications.

The developed technology will give Gefertec GmbH advantage over competitors and is one of the most important strategic aspects of the project. The seawater environment is very destructive for metal materials, so the knowledge and technological possibilities to develop new products which will be corrosion and wear resistant and can operate for a long period of time in such condition are crucial to be successful in this field. One should also take notice of material consumption during production. BuytoFly (BTF) ratio for the traditionally manufactured parts (casting, plastic working, machining) is most of the time around 1020 and sometimes even above 30. For 3DMP® BTF ratio is usually around 1.5, but never above 2.0. Shortening lead times and significant material saving are additional key strategic effects of the project. Another strong advantage of 3DMP® is the fact that it can be used for maintenance and repair operations. It is easily possible to take an existing part that ends up being broken and use software to scan it and then rebuild the product. During traditional manufacturing, shrinkage cavities, oxide notches and other defects can occur often in the product which can lead to long and expensive repairs or rejects. An alternative to this technology is WAAM, which consists of the fabrication of parts layer by layer with a wire fusion by automatic arc welding. The achievement of the project’s objectives enable to implement new manufacturing technology for corrosion resistant components that will be made of new grades of Cu based alloys. The technology of propellers production is connected with the production devices which can be also offered to the customers interested in technologies of renewable energy production and marine industry. This will enable to Gefertec GmbH to introduce the new product to the offer which increase the innovativeness and competitiveness of the enterprise. The technology readiness level TRL will reach 9 after the project. The technological processes developed within the project will be ready to implement. The planned research program is focused on the work necessary to start the industrial production of the marine propellers and other marine equipment intended for the power stations which recover the energy from the sea tides and also for ship industry. We hence believe this 3DMPWire project is of strategic importance for strengthening the European position in the emerging field of 3D printing for challenging and material-intensive environments, such as the marine sector.

Table 1. Cost comparison between wire and powder feedstock for various materials.

Fig. 1. Cost evolution requirements in order to reach a profitable business case for additive manufacturing (powder bed).

 
Fig. 2. Deposition rates for various additive manufacturing technologies.

  
Fig. 3. Global comparison of different additive manufacturing technologies.