Large-format sand moulds printed using the VX9000 – a case study

Additive manufacturing is currently used predominantly for prototypes and small production runs. The build volumes of standard systems often limit their scope of application to smaller components – a circumstance that can reinforce the impression that 3D printing is only suitable for compact applications. However, particularly in the energy sector – for example, in wind or hydroelectric power plants – entirely different scales are required: in wind turbine blades in particular, individual components such as rotor hubs can weigh up to 60 tonnes each.

Project launch: Development of the Advanced Casting Cell (ACC)

Even when working on a large scale, engineering teams are guided by the same objectives as with smaller components: maximum design freedom, reduction in weight and material usage, shorter lead times, and the possibility of decentralised manufacturing. To extend these benefits of additive manufacturing to components in the multi-tonne range, voxeljet has developed the VX9000 triple-printing system in collaboration with GE Vernova and Fraunhofer IGCV. The system marks a significant technological leap – for the first time, it scales industrial binder jetting technology to a level that meets the requirements for multi-tonne castings.

In September 2021, GE Vernova (then GE Renewable Energy), Fraunhofer IGCV and voxeljet announced the launch of a joint research project to develop a large-format 3D sand printer. The aim was to optimise mould production for cast components of the Haliade-X offshore wind turbine. The ACC was intended to be capable of producing sand moulds for individual parts weighing up to 60 tonnes – more quickly, flexibly and with greater resource efficiency than conventional moulding processes.

A key advantage of the planned technology lay in the drastic reduction in production time: Instead of around ten weeks, production was expected to take just two weeks. Furthermore, the use of additive manufacturing at the installation site promised a significant reduction in logistical effort and the associated CO₂ emissions.

The Federal Ministry for Economic Affairs and Energy supported the project as part of a technology-oriented innovation programme.

Technology platform: Binder jetting on an industrial scale

The VX9000 3D printer from voxeljet was designed as part of the ACC. It is based on voxeljet’s established binder jetting technology, in which sand is selectively solidified layer by layer using a binder. This enables the production of complex geometries with high dimensional accuracy. With a build volume of 9 x 7 x 1.8 metres, the 3D printer exceeds the build volume of all other common 3D sand printers and is therefore one of the largest systems of its kind worldwide.

In October 2023, the overall project led by GE Vernova received a grant of US$14.9 million from the US Department of Energy (DoE). Voxeljet was selected as the technical implementation partner to further develop the VX9000.

Prototype construction and system integration

Subsequently, the first VX9000 platform was assembled at Voxeljet’s headquarters in Friedberg. The system’s dimensions significantly exceed those of existing equipment – a comparison with the VX4000, previously one of the largest commercial 3D printing systems for sand moulds, illustrates the leap in scale.

In addition to its increased build volume, the VX9000 also stands out thanks to further technological advances:

• Processing of industrial foundry sands – use of cost-effective, locally available sands with high recyclability; significantly simpler preparation compared to conventional quartz sand.
• Greater layer thicknesses and improved printing technology – Layer thicknesses of up to 1 mm speed up the build process and reduce process costs.
• Offset jetting strategy – Large-format print head configuration with very short offset distances for significantly reduced build times.
• Integrable process sensor technology – Real-time monitoring of relevant process parameters ensures consistent print quality and traceability.

Validation under production conditions at Baettr Foundry

A significant milestone was reached in the summer of 2025: at the Swedish Baettr Foundry, the first large-format sand moulds produced by the VX9000 were successfully cast. A total of 20 benchmark moulds were processed in print jobs measuring up to 7.5 m in length under real foundry conditions. The alloy used was EN-DJS-400-18-LT; the final casting weighs 7,200 kg.

Results:

• Dimensional tolerances were well within the required specifications.
• Significantly higher dimensional accuracy of the components compared to traditionally manufactured large moulds.
• Significantly simpler assembly of the mould.
• Reduced cleaning effort for the components due to an improved surface finish and fewer burrs.
• Smooth casting process under series production conditions.
• No discernible casting defects.
• Initial insights into process optimisation in terms of handling and workflow.

The validation confirmed the system’s suitability for industrial use. The VX9000 met both the geometric and casting requirements for critical large components.

“Baettr has been working with Voxeljet since 2018 on the further development of sand 3D printing. The progress is clearly evident: today, the cores are larger, easier to assemble and continue to meet the highest standards of accuracy and quality. Building on these positive experiences, we intend to continue playing an active role in shaping the future of this technology,” explains Nicolas Ory-Studer, Project Manager at Baettr.

Range of applications and scalability

The VX9000 was primarily developed for the offshore wind industry, but can be adapted to numerous other fields of application. These include:

• hydro turbines (e.g. Francis impellers, spiral casings),
• heavy-duty rotor hubs and gearbox housings,
• structural components for large-scale installations in the energy or infrastructure sectors.

Voxeljet as an engineering partner for large-scale AM solutions

With the development of the VX9000, Voxeljet reaffirms its role as a technology leader in the field of large-format additive manufacturing for the foundry sector. The combination of many years’ experience, engineering expertise and flexible machine architecture makes the company a reliable partner for industrial projects with high demands in terms of customisation, dimensional accuracy, speed and sustainability.

The VX9000 demonstrates how large-format additive manufacturing is becoming an industrial reality. With its modular design, precise binder jetting technology and digital process integration, it is more than just a technological prototype – it is a game-changer in the field of large-scale casting.