Across sectors such as electric aviation, high-performance automotive and marine, engineers are being asked to deliver machines that are not only more efficient, but significantly lighter and more powerful too. Meeting these demands will require power densities well beyond what is considered state of the art today. Here Nick Simpson, Professor of Electrical Machines at the University of Bristol, a CWIEME Berlin education partner, explains why achieving this will mean pushing power density above current levels.
 

According to UK technology roadmaps from the Advanced Propulsion Centre and the Aerospace Technology Institute, electrical machines will need to reach power densities of between 9 and 25 kW/kg by 2035. That represents up to a five-fold increase on what is currently available. Incremental improvements alone will not get the industry there. Something more radical is required.

Rethinking power density 

Mass power density is the ratio between how much power a machine can produce and its own mass and is typically measured in kW/kg. Traditional manufacturing methods impose geometric and material constraints that limit how far this ratio can be pushed. Additive manufacturing (AM), by contrast, offers designers much more freedom.

Electrical machines consist of both passive components, such as housings and structural elements, and active components, including windings, electrical steels and permanent magnets. On the passive side, AM enables advanced lightweighting using lattice and gyroid structures. These allow material to be removed where it is not mechanically required, maintaining stiffness while significantly reducing mass.

At the same time, AM allows cooling channels and jackets to be integrated directly into structures and placed precisely where heat is generated. Improved thermal management is critical, as temperature limits are often the defining constraint on power density. However, the most transformative opportunity lies in the active components.

New geometries

Conventional electrical machine design is heavily influenced by how components can be manufactured. Windings, for example, are typically produced by winding round or rectangular conductors, a process that is highly automated but inherently restrictive.

Additive manufacturing changes this entirely. If windings can be printed, they can be produced in almost any geometry. Individual conductors can be shaped and positioned to optimise electromagnetic performance, thermal behaviour and mechanical integrity simultaneously.

This geometric freedom allows engineers to explore entirely new machine topologies, guiding magnetic flux and electrical current in ways that are simply not possible using traditional manufacturing techniques. Rather than forcing designs to fit the process, AM allows the process to follow the design.

From prototyping to production

Additive manufacturing is often viewed primarily as a prototyping tool, and its value in this role is undeniable. Because AM is a fully digital process, tooling costs are drastically reduced. Designs can be iterated quickly, updated digitally and tested physically at a fraction of the cost of conventional methods.

However, AM is increasingly moving beyond prototyping into end-use production, particularly for high-performance, low-volume applications. In electrical machines, this transition has been driven by the need to remove manufacturing constraints altogether and start from a blank design sheet.

By treating additive manufacturing as a production-ready process rather than an experimental one, researchers and engineers can evaluate what an electrical machine could look like if geometry were no longer the limiting factor.

Materials breakthrough

Historically, material performance has been a significant barrier to the adoption of additive manufacturing in electrical applications. While structural materials such as aluminium and steel have reached parity with conventionally manufactured equivalents, highly conductive materials like copper have posed greater challenges.

Copper’s high reflectivity and thermal conductivity made it difficult to process using traditional laser powder bed fusion techniques. Over the last few years, however, advances such as higher-power lasers, alternative wavelengths and new AM processes, including binder jetting, have overcome many of these limitations.

Today, additively manufactured copper and aluminium conductors can achieve performance comparable to drawn materials, removing a critical adoption barrier. This is essential: without matching incumbent material performance, even the most innovative geometries will fail to gain industrial acceptance.

Soft and hard magnetic materials remain more challenging. Conventional laminated electrical steels are specifically designed to reduce eddy current losses, and replicating this behaviour through additive manufacturing is complex. While research is progressing globally, this remains an active development area rather than a solved problem.

Adoption challenges 

Despite its promise, additive manufacturing adoption in electrical machines has been relatively slow. This is not due to resistance to innovation, but rather the reality of industrial decision-making.

AM requires significant capital investment, specialised knowledge, new health and safety practices and complex post-processing steps. With relatively few large-scale commercial success stories in electrical machines, many manufacturers remain cautious.

A further challenge lies in the skills gap. Designing for additive manufacturing, particularly for active electrical components, requires expertise that spans electromagnetics, materials science, thermal management and computational design. Outsourcing production to third-party print bureaux is possible, but without in-house understanding, achieving consistent, high-performance results can be difficult.

Industry collaboration

Universities play a critical role in addressing both the technical and skills challenges associated with additive manufacturing. Beyond developing new processes and materials, they are responsible for educating engineers who can operate in a digital design and digital manufacturing paradigm.

Additive manufacturing is increasingly displacing traditional, human-driven CAD approaches with computational and algorithmic design methods. This represents a profound shift in how engineers conceive, design and optimise components, and it will take time for industry and education to fully align.

Industry events such as CWIEME Berlin provide a vital platform for this alignment. They enable researchers, manufacturers and suppliers to exchange knowledge, identify bottlenecks and explore how emerging technologies can be translated into real-world applications.

Looking ahead

Over the next five to ten years, additive manufacturing is likely to become a standard tool for producing high-performance electrical machine components, particularly in sectors such as aerospace, premium automotive and marine applications.

Large-format AM systems, improved productivity and greater process repeatability will expand the range of components that can be produced. Additively manufactured windings, in particular, offer the potential for significant gains in efficiency, thermal performance and power density.

However, additive manufacturing is unlikely to fully replace conventional processes. Instead, it will act as a complementary technology enabling extreme performance where required, while also informing more manufacturable designs that deliver a large proportion of the benefit at lower cost.

In this sense, additive manufacturing is not just a manufacturing solution. It is a lens through which the electrical engineering community can re-imagine what electrical machines are capable of and how close they can come to meeting the demands of a fully electrified future.

Additive manufacturing will be an area of focus at CWIEME Berlin, which is held at Messe Berlin from May 19 to 21, 2026. To find out more and stay ahead of the trend, register for a visitor ticket today.