FEMM Hub Annual Report 2025 by Laura L O'Keefe

Annual report 2025

the future electrical machines manufacturing hub putting UK manufacturing at the forefront of the electrification revolution

WELCOME As we enter the final year of the FEMM Hub’s 7-year programme of research, this annual report brings the main findings of the various research programmes up to date and demonstrates the growth in our dissemination and technology transfer activities. As you will see from this year’s report, we continue to broaden the range of topics covered in the Hub portfolio through a combination of feasibility studies with other research groups from across the UK and through the drawing in of additional expertise from the core Hub partners. Our research remains focussed on the manufacturing of key machine components and the underpinning engineering science that develops knowledge to improve future processes and design.

year and an on-going piece of work to increase our offering into the secondary school sector having previously focussed largely on the primary sector. We would welcome approaches from across the UK deliver further school sessions. You will also see from the report, that the team has been active at conferences and trade exhibitions in disseminating and promoting the research and main findings to a wider audience. We have also produced a series of short-videos highlighting our research and I would encourage you to take a look at these on our website. Finally, I wanted to take this opportunity to specifically thank Jill Miscandlon from Strathclyde University for her commitment and leadership in the Hub as she moves to a new role in the sustainability sector. Jill was an original member of the team that put together the original bid in 2018 and has been the driving force behind introducing and then expanding the Hub’s activities in sustainability and the circular economy aspects of electrical machine manufacture and re-manufacture.

It is gratifying to see some of our earlier PhD students graduating over the past year. Through the support of the EPSRC iCASE scheme, partner institutions and industry partners, they have been able to undertake projects aligned with the Hub research and be active members of the wider team. They go off to the next stage of their careers with our best wishes and thanks. Our schools outreach activity continues with some notable events over the past

Professor Geraint Jewell FEMM Hub Director 3

CONTENTS

ABOUT US

OUR RESEARCH

Aims................................... 6 Hub Management.............. 7 Our Team........................... 8 EDI..................................... 9 Industry Partners............... 10 IAB..................................... 11 SAB.................................... 12

Grand Challenge 1...................... 14 Grand Challenge 2...................... 25 Cross Cutting Theme...................36 Alligned Projects ........................ 50 PhD Projects................................60

FEasibilitY

Publications

Project Updates.................36

List of outputs............................... 76

Outreach Outreach............................ 80 Conferences....................... 84 QRM................................... 88

Aims and objectives

The FEMM Hub addresses key manufacturing challenges in the production of high integrity and high value electrical machines in the aerospace, energy, high value automotive and Premier consumer sectors.

1 2 3 4

To establish electrical machine manufacturing as a recognised research discipline in the UK with a critical mass of activity which is internationally leading. To develop innovative manufacturing processes and technologies to improve the integrity and in-service reliability of high performance electrical machines. To bring rigorous leading-edge manufacturing systems and digital manufacturing research into high value electrical machine manufacture with ultimate control and flexibility. To embody the research findings in an array of hardware demonstrators and modelling tools to support Technology Readiness Level (TRL) scale up and wider industry/academic engagement.

To rapidly transition emerging technology through to industrial application by pulling proof of principle/concept manufacturing systems through to manufacturing research demonstrators prototypes for industry to work on alongside Hub researchers and develop for application.

To create an open and inclusive academic, innovation and industry communities around the Hub that provides supported access to the research outputs we develop and stimulates new collaborations.

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To improve the UK skills base, including within partner companies, in the field of electrical machines and their manufacture. To support UK manufacturing industry as electrical machines increasingly become core products in new sectors.

Hub Management Our Executive Team is made up of the Director, Deputy Director, Hub Manager, AN EARLY CAREER RESEARCHER AND representatives from each of our academic partners.

Hub Director

Deputy Director

HUB MANAGER

Professor Geraint Jewell

Professor Ash Tiwari

Dr Laura O'Keefe

The University of Sheffield

Dr Glynn Atkinson

Dr Jill Miscandlon

Dr Lloyd Tinkler

Newcastle University

NMIS

AMRC

Dr Xiao Chen

Dr Nick Simpson

Early Career Representative

University of Bristol

Meet our team Dr Mehrad Kazemi Amiri

Dr Glynn Atkinson

Strathclyde University

Newcastle University

Dr michael farnsworth

lindsey farnswoRTH

Dr Daniele De Gaetano

Dr xiao chen Sheffield University

Dr steve forrest Sheffield University

Dr jason ede

Dr Anna Ermakova

Dr Dave Hewitt

Prof. Geraint Jewell

AMRC

Sheffield University

Dr Hassan Ghadbeigi

Sheffield University

Bristol University

Sheffield University

Dr MEHMET KULAN

Prof.Barrie MeCROW

Dr Jill Miscandlon

Professor Ben Morgan

Dr Laura O’Keefe

AMRC

Sheffield University

Prof.RAB SCOTT

Dr Nick Simpson

Dr Lloyd Tinkler

Prof. ash tiwari

Dr Divya tiwari

Newcastle University

Dr Luke Saunders Newcastle University

Dr Yusuf Ugurluoglu

Newcastle University

AMRC

Prof. Michael Ward NMIS

Sheffield University

NMIS

AMRC

Bristol University

Dr Rahul Yadav

Dr alexei winter

Sheffield University

AMRC

Sheffield University

Prof. Zi QIang ZHu Sheffield University

Sheffield University

ProF. Robin Pursehouse

Sheffield University

equality, diversity and inclusion We actively promote a culture where the diversity of the staff involved in the Hub is positively valued and celebrated. We believe that diversity in all its forms delivers a greater impact to our research and enhances the experience of our staff, students and partners. The Hub’s commitment to EDI is demonstrated and promoted through our internal and external communications. The FEMM Hub Equality, Diversity and Inclusion committee was set up to maintain a fully inclusive culture that is proactive in initiating change and driving forwards best practice in equality and diversity matters. The committee is made up from a representative from each of our partners as well as the FEMM Hub Manager.

Dr Divya Tiwari MAC, University of Sheffield

Dr Jason Ede EEE, University of Sheffield

Dr Abbas Kazemi Amiri University of Strathclyde

Lindsey Farnsworth University of Sheffield

Dr Laura O'Keefe University of Sheffield

Dr Glynn Atkinson Newcastle University

EDI TRAining - Inclusive Language During the September 2024 Quarterly Meeting at Strathclyde University, the Equality and Diversity Office delivered a session on Inclusive Language for our team. The session looked at inclusive language, why it matters, and how to use it. We learned about inclusive language across gender, race, sexuality, and disability as well as gender-neutral language. The interactive session empowered us to talk more confidently about EDI issues. The trainer highlighted the benefits of using inclusive language within the FEMM Hub which included improvements in workplace culture and enhancing communication effectiveness.

Industry partners

Our partners help us work towards our vision of putting UK manufacturing at the forefront of the electrical revoultion and have helped shape our current and future research programme.

industry ADVISORY BOARD Our IAB brings together senior figures from the each of the FEMM Hub’s industry partners. They appraise and advise on the impact activities to maximise the opportunities for knowledge exchange and ensure the Hub delivers impact for UK industry.

Carpenter Technology Corporation

Siemens Gamesa

Ziad Azar

Maamar Benarous

Simon Brockway

Duncan Brown

Harry Felton

Alan Lindsay

Bartosz Lukasik

David Moule

Lars Sjoberg

Natan Aronhime

McLaren Applied

Tannlin

Daniel Smith Dyson

Collins Aerospace

Hexagon

Protean Electric

Airbus

Rotary Engineering UK

Hoganas

Chris Redfern

Simon Swallow

TWINN

Chuanli Zhao GKN

STRATEGIC ADVISORY BOARD - Provides feedback on the progress and outcomes of the Hub’s research programme. - Advises on the degree to which the Hub’s vision is being delivered. - Provides feedback on whether the Hub’s activities are sufficiently aligned with industry projections and government policy.

- Advises on emerging topics or trends in academic and industrial R&D on electrical machines and their manufacture.

- Advises on opportunities for dissemination through means that would influence policy and

industry practice and, where appropriate, help facilitate the realisation of these opportunities.

Avo Reinap

Adam Clare

Gareth Edwards Dr Kiran Harish Thomas Marks Manoj R. Shah NPL

ATI

David Smith

Sam Turner

Duc Trouong Pham

John Taylor

Lund University

TTP

UBC

HVM Catapult

University of Birmingham

SG Techologies

AEMT

Rensselaer Polytechnic Institute

Peter Tavner

Tetsuo Tomiyama

University of Durham

The International Professional University of Technology in Tokyo

OUR RESEARCH Grand Challenge 1

Manufacturing-led innovation in electrical machines This theme is concerned with realising the dividends that come from much closer integration between innovation in electrical machine design and advanced manufacturing methods. 1.1: Realising novel machine design freedoms from innovative manufacture. 1.3. Manufacturing of light-weight and multi-functional structural components. 1.4. Manufacturing the novel and non-standard materials.

Grand Challenge 2

Process innovation, monitoring and simulation This theme is focused on the numerous processes that underpin electrical machine manufacture. The research will draw heavily on modelling and simulation to explore the influence of current and emerging processes on final machine performance. 2.2: Manufacturing high performance coils and ultimate control. 2.3: Manufacturing technologies for flexibility and customisation.

Cross cutting themes

A central thread of activity linking our research outputs Cross cutting (X) themes underpin our Grand Challenge (GC) themes. Each GC theme incorporates elements each of the X themes in order to develop a deeper understanding and maximise FEMM Hub outputs. X1: Sustainable manufacturing of electrical components for the circular economy. X2: In-process tracking and tractability for zero-defect manufacture of electrical machines. X3: Roadmapping and technology reviews. X4: Demonstrator.

Aligned projects

Research which links with the strategic vision of the FEMM Hub - From nominal core properties to in-service performance. - Influence of cut edge damage on mechanical and magnetic properties in electrical machine laminations. - Feasibility calls.

Grand challenge ONE Manufacturing-led innovation in electrical machines

This theme is concerned with realising the dividends that come from much closer integration between innovation in electrical machine design and advanced manufacturing methods.

1.1: Realising novel machine design freedoms from innovative manufacture. 1.3. Manufacturing of light-weight and multi-functional structural components. 1.4. Manufacturing the novel and non-standard materials. 14

1.1: Modular design and advanced thermal management of electrical machines Led by Newcastle University We have appointed a third research associate, Dr Mehmet Kulan, alongside Dr Luke Saunders and Dr Yusuf Ugurluoglu bringing expertise into this work package covering Magnetic, Mechanical and Manufacturing engineering. GC 1.1 aims to increase the power density of electrical machines within the same thermal limits through changes to the machine design and construction methods. Modularisation of the stator enables greater access and control to the coil winding process, a denser, more thermally conductive coil which can operate at higher loadings within thermal limits. Further gains can be obtained by incorporating advanced thermal management into the module. The challenges to be addresses include more components, mechanical, thermal and magnetic interfaces. We are methodically exploring the aspects below to offer insight to manufacturers.

Thermal INVESTIGATION Experimental analysis of a complete, non segmented stator, Figure 1, is being compared to results from two variants of a segmented stator, Figure 3. Both segmented stators use a chevron feature to locate and retain the stator sections in a ring upon assembly. Version 1 (Figure 2 centre) is a direct segmented version of the complete stator in figure 2 above. Version 2 (Figure 2 right) has a flat inner core back face at 90° to the tooth to aid coil placement.

Figure 1: Complete (non-segmented) stator

By having a more precise winding process, when compared to in slot winding, we aim to show oils with improved thermal properties which will enable a greater electrical load for the same temperature rise. Greater precision in the winding process will also increase the slot fill factor, from ~40% for a traditionally wound slot to >50% for the bobbin wound segmented tooth.

Figure 2: Top left: stator segments partially aligned. Top right: tooth details. Bottom left: curved (1) and flat inner face (2) tooth segments. Bottom right: 208 turn wound coil.

2DFE thermal simulation (dynamic and steady state) of the concentrated wound tooth was carried out with a current density of 10A/mm2 and adiabatic boundary on the segment edges (to force radial heat dissipation) and a heat transfer surface on the coreback into a 20°C Ambient environment. The simulated thermal plot and coil temperature rise is shown in Figure 4. An experimental setup was designed to closely mimic the 2D thermal simulation. Three wound stator segments are aligned within a thermally insulated, double wall chamber made from 3D Printed ABS thermoplastic, Figure 5. The central tooth is thermally balanced either side, akin to the simulated adiabatic boundary condition.

Figure 3. 2DFE thermal simulation of a single slot under electrical load.

Figure 4: The experimental setup, in environmental chamber test and thermal camer imaging during test.

Over the next few months a test programme will gather results for various slot lining materials, increased slot fill factors and from a professionally wound non-segmented stator for comparison. Initial results are promising. The thermal transient and steady state temperature of the tooth face and the average coil temperature do closely follow the 2DFE simulation in – where a coil average temperature was simulated at 68.5°C and measured at 74°C. Figure 5 shows the thermal transient for the average coil and core face temperature (left) and the steady state temperature rise as a function of coil power. Data is measured for both the curved and straight inner slot faces in Figure 2. Initial results also show a difference in the thermal performance of the two stator segment designs. This is more pronounced at the higher power loading and a clear difference is seen between the curved inner segment (design 1) and the flat inner (design 2). It is proposed that the flat surface and 90 degree angle result in a more ordered coil arrangement and subsequently an improved thermal path and lower temperature rise.

Figure 5: Thermal transient (left) and steady state temperature rise -v- power (right).

Stator Modal Analysis Working with the School of Mechanical Engineering, University of Sheffield we have been carrying out modal analysis of non-segmented and segmented stators at the various stages of assembly to identify where and how sources of mechanical instability and vibration occur in the complete Machine. 17

Using a Tap test; an Impact hammer and accelerometers used for data collection the Vibration data is collected from multiple taps at specific points on the stator. Advanced data analysis identifies natural frequencies and Mode shapes are extracted and visualized using ANSYS. This work continues with a journal paper planned for mid-2025 summarising the analysis of all three stator topologies.

Stress and vibration Analysis of Separated teeth The mechanical performance of fully removable teeth is being investigated with the third demonstrator stator. Fully removable teeth with a variety of interfaces are being investigated for vibration and wear. The dovetail joint demonstrated a relatively even stress distribution and effective restriction of both axial and radial movement, though its performance is sensitive to precise manufacturing tolerances. The jigsaw joint, characterised by interlocking teeth, exhibited pronounced stress concentrations at the edges of contact surfaces, primarily due to the sharp corners inherent in its design, underscoring the need for geometry optimisation. Similarly, the stepped jigsaw joint, while offering additional axial movement restriction through its horizontal step feature, also showed significant stress at contact surface edges and sharp corners. These findings highlight the potential for enhanced stability in both jigsaw and stepped jigsaw topologies, but further design refinements are necessary to mitigate the observed stress concentrations.

Fig. 6: Equivalent stress distribution dovetail, jigsaw, and stepped jigsaw topologies, from left to right.

1.3: Light-weighting and multi-functional non-active components Led by University of Strathclyde One of the main streams of work for GC1.3 has been the development of a methodology to fully integrate manufacturing constraints and opportunities with the machine design considerations. The novelty in this work includes material data specific to individual manufacturing process in the design of components. Not only does this reduce the risk of over-engineering components, it also allows for an assessment of when and where expensive materials and processing routes can be put to best use. The team working on GC1.3 published “A Manufacturing Driven Design Methodology to Lightweighting of the Structural Elements of a Permanent Magnet Electrical Machine Rotor,” in IEEE Access [1]. This paper was the culmination of over a year’s work, optimising how the manufacturing requirements can be optimally integrated into the design stage of electrical machines Figure 1: Spoked hub design of electrical machine rotor, as discussed in [1] components. Typically, electrical machines are designed with little or no input from a manufacturing production viewpoint, and this can often lead to cost increases and time delays as designs are iterated to accommodate for manufacturing limitations. This paper proposed a methodology to fully integrate the mechanical design and manufacturing process routes into electrical machine design, and illustrated the benefits of such a process within the context of lightweighting a permanent magnet rotor for an aerospace electrical machine. Within the methodology proposed in this paper, several alternative configurations of rotor design were considered with appropriate manufacturing routes identified at the initial concept design. Different material and manufacturing constraints were identified in this paper, as well as the impact that the manufacturing process can have on the final component. These impacts were then embedded into the initial design procedures. The final section of the paper demonstrated an application of this methodology, and discussed the features which offer opportunities for achieving economically lighter weight design through the integration of manufacturing into the design procedure.

Figure 2: Schematics for the three different design options considered [1]

Figure 3: Comparison of mass of the spoked rotor hub design when manufacturing specific material data is used [1]

The case study in this paper presented three designs of a rotor hub and shaft, shown in Figure 2, and considered the effect on weight when manufacturing specific material data is used. The choice of manufacturing route can greatly affect the yield stress of the final component, and this was included in the modelling to highlight potential lightweighting potential by selecting an optimal method of manufacture, as shown in Figure 3. Work is now ongoing for the follow up to this paper, where a second paper will focus on more detailed modelling which will further highlight the benefits of introducing manufacturing considerations into the design of electrical machine components. The new stream of work, GC1.4, in conjunction with GC2.3, focuses on understanding what a manufacturing system for small batch electrical machines would look like. The approach developed for the type and volume of machines considered in the FEMM builds on several manufacturing system ideas that have already been developed. Examples can be found in academia and industry of Dedicated Manufacturing Systems (DMS), Reconfigurable Manufacturing Systems (RMS), and Flexible Manufacturing Systems (FMS). A Flexible Manufacturing System is a manufacturing system in which there is some amount of flexibility built in that allows the system to react to a certain degree of change. Reconfigurable Manufacturing Systems (RMS) are designed for rapid changes in structure, hardware, and software, in order to quickly adjust its production capacity and functionality within a series of part families. Manufacturing processes were generated for each of the four key elements of the machine: rotor, stator, coils, and non-actives. They were then ranked against each other based on a variety of drivers including process speed, process and tooling flexibility, and cost. The highest ranked manufacturing methods were then combined to produce a flexible factory option, which is shown in Figure 4: Flexible factory set-up with a combination of flexible and reconfigurable cells, where blue and orange cells represent stator and rotor manufacture, Figure 4. respectively, and grey cells represent inspection, testing, and general assembly cells. Flexible and reconfigurable cells are shown with a designation of ‘F’ and ‘R’ respectively. 20

The net zero 2050 targets which have been set out by many countries across the globe will rely on the electrification of transport and energy sectors, which in turn will require an increase in the power density and volume of electrical machines. The key aim of this work is to understand how we ensure manufacturing solutions are flexible enough for future production challenges. This includes not only the ability to handle different machine topologies currently being manufactured, but also the ability to deal with radical design changes that might come with the need for ever increasing power density requirements. In 2022, the team working on GC1.3 also designing and delivered a training course for FEMM hub members “Manufacturing Opportunities for Future Electrical Machines”. This course was delivered by colleagues at the Advanced Forming Research Centre (AFRC) and the Advanced Manufacturing Research Centre (AMRC), and introduced novel manufacturing routes which could be utilised for the manufacture of non-active components in electrical machines. This course was well attended, with over 75 participants, and will be run again in future. With a focus on the wind energy sector, Dr Abbas Mehrad Kazemi Amiri led a team of researchers to deliver the technology white paper “Design and Manufacturing Challenges and Opportunities for Offshore Wind Turbine Electrical Generators”. The main objective of this Technology White Paper, in which the existing and future challenges in cost-effective design and manufacturing of the next generation of direct-drive electrical generators in offshore wind turbine generator systems are identified, and corresponding opportunities to address those challenges are discussed. It has tried to contribute to finding answers to the following questions: a) what are the current manufacturing methods? b) what are the challenges with scale-up in size and number? c) what are the major differences between the direct-drive generator and the conventional ones for wind turbines that influence the manufacturing process?

Figure 5: Graph Showing Required Wind Energy Capacity Growth in Order to Reach Net Zero by 2050 [2]

Direct-drive permanent magnet generators are now dominating the offshore supply chain. In offshore wind farms, the overall cost of energy is pushing the turbine design to be larger in power and slower in rotational speed. Due to the high demands on wind energy as the major low carbon source of energy, significantly more wind turbines (particularly offshore) need to be designed, manufactured and installed. This white paper relies on the literature review, existing information in the public domain as well as interviews with experts, as the two former sources have been found to be quite limited. More information on this white paper can be obtained by contacting Dr Amiri or Dr Jill Miscandlon (both University of Strathclyde).

For the next phase of this research, there will be two main work streams: • Work stream 1: Continuation of current lightweighting design development, with methodology validation and prototype testing • Work stream 2: Manufacturing-driven design of down-scaled wind turbine direct-drive generator Work stream 1 will build on previous research and will produce high-fidelity finite element modelling and analysis of family tree design candidates presented in [1]. “A Manufacturing Driven Design Methodology to Lightweighting of the Structural Elements of a Permanent Magnet Electrical Machine Rotor” [1] set out a methodology for determining the optimal material and manufacturing route for specific electrical machines components. The next stage will involve stress and compliance analysis of the design candidates where the joint manufacturing and mechanical constraints are imposed, and the use of different metallic materials with the mechanical properties associated with the manufacturing process taken into account. Based on the results of the finite element modelling, a design will be chosen for prototype manufacture. Mechanical tests will then be conducted on the manufactured candidate design under operational loads. Shaft and hub mechanical strength tests will be conducted, including stress, deflection, tolerance, vibration measurements, and verification against the finite element analysis results. Work stream 2 will follow on from the white paper “Design and Manufacturing Challenges and Opportunities for Offshore Wind Turbine Electrical Generators”. Downscaling, modelling, redesign and testing will be conducted in order to establish the comparison with the baseline design. An adaptation of the design and manufacturing methodology developed in [1] will be applied to the rotor of a direct-drive generator to create novel candidate design models. Finite element modelling will be utilised for a multi-material rotor design, which aims to utilise carbon fibre composite in the deflection hotspots in combination with a metallic structure for further lightweighting achievement in addition to the above. Focus will be given to the achievable tolerances, mechanical strength of the novel rotor design, and electromagnetic losses in the generator.

REFERENCES [1] Miscandlon et al., A Manufacturing Driven Design Methodology to Lightweighting of the Structural Elements of a Permanent Magnet Electrical Machine Rotor,” IEEE Access, vol. 10, pp. 117449-117468, 2022 [2] Global Wind Energy Council. Gwec - global wind report 2022. Technical report, Global Wind Energy Council, 2022

1.4. Manufacturing the novel and non-standard materials Led by University of Strathclyde A new work stream was launched to focus on novel and non-standard electrical machine materials. This work package is supported primarily by colleagues in NMIS and the AMRC, and is focusing on two key areas: 1. Materials and manufacturing processes for low temperature operation 2. Advanced materials and manufacturing technologies for superconducting machines Exciting developments over the past few years have included the design of traditional electrical machines for use in cryogenic environments - mainly for use in hydrogen powered aircraft - and the further development of fully superconducting machines. Both technologies are developing rapidly, but the manufacturing technologies that will be required for each- especially when larger volumes will be required- are still unclear. One of the aims of GC1.4 is to assess the current state-of-the-art in design and material selection for low temperature applications, and link this to the manufacturing research that is already ongoing within the hub.

Figure 1: Temperature dependence of resistivity [1].

The first task was to conduct a literature review on the behaviour of standard electrical machine materials at low temperatures. Typically, the cryogenic temperature range is an interval from approximately 123 K to 0 K. Molecular motion at these temperatures within the material structure slows down significantly, causing an alteration of properties. Conventional materials experience a loss in ductility, strength, electrical resistance and increased brittleness, leading to structural failures or performance degradation in applications requiring reliable operation under such conditions. The literature review evaluated the material options viable for operation under low-temperature environments, focusing on materials that can maintain their tensile properties and endure the rigorous thermal cycles associated with cryogenic environments.

Aluminium alloys, particularly the 6000-series, exhibit enhanced tensile strength and ductility at temperatures as low as liquid helium and are historically recommended for such environments. However, the impact of thermal cycling and fatigue remain an open area for research. Stainless steel, notably the 300-series, is also an ideal choice, retaining its strength and toughness under cryogenic service. Stainless steel alloys have been extensively used and researched since the early days of the American Space Programme and are proven to perform well under thermal cycling. The fatigue life of several alloys was also investigated and overall, low temperature operation appears to increase the number of cycles to failure for alloys including stainless steel, Inconel, and titanium. While promising for its attractive strength-to-weight ratio, researched titanium alloys are only suitable down to 77 K. Below this temperature, the increased brittleness and notch sensitivity prevent titanium from being a suitable structural option. Between 77 and 423 K the material shows potential, however, more analysis is 23

Figure 2: Results of tensile tests conducted at different temperatures for (L) aluminium and (R) stainless steel, as reported in [2] and [3] respectively.

needed for a concrete conclusion. GC1.4 has also begun a feasibility project on a hyperconducting electrical machine using novel winding materials and technologies. The aim of this work is to understand what is the ‘optimal’ design for a hyperconducting machine, when the same weighting is given to performance and manufacturability. Research is ongoing into novel winding materials, such as high purity aluminium, and hybrid windings and conductors, where performance will be assessed against standard copper windings and high temperature superconducting topologies. High purity aluminium is extremely soft Figure 3: Results of fatigue strength tests conducted material and hence difficult to process, but is a better on different materials at different temperatures, as choice than both copper and superconductors in a reported in [4]. specific temperature range, typically below 77 K. The manufacturing challenges and potential supply chain for such an exotic material is also being investigated, as the manufacturability and scalability of are still unknown variables. The output from this work stream will include a summary report of the challenges and opportunities for hyperconducting electrical machines, with a focus on the key applications and operating temperatures that could benefit specifically from this technology. [1] Afefy, Ahmed & Kamel, Ahmed & Hesham, Abdelrahman & Elbouriny, Ziad & Amr, Ziad & Fathy, Mariam. (2022). A Review On Superconducting Materials and Their Applications. 10.13140/RG.2.2.13919.27040. [2] Yanpu Wang et al., “Deformation behavior of pure aluminum at room and cryogenic temperatures”, Journal of Materials Research and Technology, 2024, pages 2355-2366. [3] Suning Li et al., “The behaviour and deformation mechanisms for 316L stainless steel deformed at cryogenic temperatures”, Materials Science and Engineering: A, 2023, pages 145-155. [4] Chetan Singh et al., “Exceptional fatigue-resistant austenitic stainless steel for cryogenic applications”, Applied Materials Today, 2024, pages 1-7.

Grand challenge TWO Process innovation, monitoring and simulation

This theme is focused on the numerous processess that underpin electrical machine manufacture. This research will draw heavily on modelling and simulation to explore the influence of current and emerging processes on final machine performance. 2.2 Manufacturing high performance coils and ultimate control. Bristol: Additive Manufacturing of High Performance Electrical Machine Windings. 2.3 Manufacturing technologies for flexibility and customisation. 25

2.2. Manufacturing high performance coils and ultimate control Led by University of SHEFFIELD This Grand Challenge is concerned with manufacturing of high-performance electrical machine coils, with controlled placement of conductors within the coil geometry. The focus is on producing multi-layer coils in solid bar type conductors and hollow bar conductors, typically with a square cross-section or rectangular cross section with a small aspect ratio. The hollow conductor contains a small duct along the centre of the conductor, through which a coolant fluid is passed, and provides effective thermal management by direct removal of heat from the conductors, rather than relying on cross-slot heat transfer. Bar conductors provide scope to either increase the current capacity of the coil, through improved utilisation of the stator slot area, and through improved heat transfer across the coil / slot, or to reduce copper loss. This can enable improvements in power density or torque density of the electrical machine. The adoption of hollow conductors allows direct removal of heat from the conductor to the coolant fluid, albeit with a reduced copper area, and a comprehensive investigation of thermal performance has been completed within this work theme. The research aims to address the challenges with forming coils in a solid and hollow bar type conductor, by incorporating; managed layer transitions into the end windings, minimised end winding length, spring-back compensation, and minimum bend radii constraints into the manufacturing process. A method has been developed method to wind bar type copper conductors onto a former, that is a representative geometry of the stator tooth. To maintain parallel conductors within in the coil active region, whilst winding from the inside of the coil outward, the bar conductor feed must change layers on each turn, to prevent winding on top of the previous turn and increment by one layer, per turn, along the tooth depth. By ensuring that the conductors remain parallel to each other and to the sides of the stator tooth, and layer changes do not occur in the coil active region, the slot area utilisation is maximised. The method of manufacturing this coil type is described in Figure 1: CAD model of the proposed coil geometry, with nested layer change further detail in the 2024 annual report. A CAD model of the proposed features in the end winding region. coil with integrated layer changes, is shown in Figure 1. The approach taken here is to pre-form layer change features at precise locations in the conductor feed and linearly position the coil former such the incoming turn is laid down next to the previous turn. The layer change features nest in the end winding of the coil and allow layers to be established along the depth of the stator tooth and then outward from the tooth, as a repeatable and automated process. The 26

intention is that conductors occupy a unique location within the coil, without leaving unnecessary voids in the slot, and include a location for the coil lead in and lead out.

Bar winding demonstrator hardware The main activity over the last year has been in establishing the hardware demonstrator to validate the proposed bar wound coil manufacturing process, commissioning and performing lab-based trials. These trials include the forming of the offset bend that creates the layer change feature, and trial coil winding. The coil forming demonstrator hardware is designed to install on a commercial winding machine (Winding Technologies WT500), without permanent adaptation. A mechanical coupling links the winding machine tool holder to a ball spline drive shaft, which transfers torque to the coil former, whilst allowing linear movement of the former. The angular position of the former is measured using a resolver coupled to the splined shaft and the linear position of the former is controlled using an electromechanical actuator with a servo motor. The coil winding demonstrator hardware, assembled for laboratory trials, is shown in Figure 2. The key elements are a press forming stage, that forms the layer change geometry in the bar conductor feed, and a coil forming stage with rotary and axial position control. Laboratory based coil winding trials are ongoing, prior to installing the press forming and coil forming assemblies on the winding machine, however there is no means of applying representative tension to the bar conductor feed.

Figure 2: Images of the coil winding demonstrator hardware, during lab-based testing and commissioning. 27

The intended process is that the conductor is fed from a spool (Figure 2a), through a 2-plane wire straightener (Figure 2b), through the press stage (Figure 2c) and onto the coil former (Figure 2e). The former will pause rotation in a defined angular position and the layer change feature is then formed in the conductor feed. This angular position of the former will determine the location that the layer change offset bends are formed in the conductor feed and ultimately the location that the layer change is sited within the wound coil geometry. A set of tooling (Figure 2d) creates the layer change feature in the conductor feed, as an offset bend with two equal and opposite bends, in one operation. The tooling is interchangeable to allow iterations of tooling design to be trialled. The top half of the tooling is located on a plate (Figure 2c) that is constrained using linear bearings, allowing motion along a single axis. The press force and linear movement of the traversing plate are provided by a pneumatic cylinder. Stopper bolts limit the travel of the moving plate, to prevent deforming the profile of the conductor, by the tooling, whilst the bends are formed. In addition, the applied force can be limited by the associated pneumatic regulator. The bottom half of the tooling is fixed and located in the base plate of the press, such that the two parts of the tooling meet correctly. Once the offset bends are formed in the conductor feed, the former increments by 1 full turn, whilst the linear position of the former is adjusted, such that the incoming turn is laid next to the previous and the layer change occurs in a repeatable and accurate location within the end winding. The tooling is designed such that the net shape of the offset bend formed in the conductor feed, has a shift of 1 conductor width, when subject to the appropriate winding tension, as illustrated in Figure 3. Due to spring-back in the material, a degree of over-bend is necessary in the tooling, to achieve this net shape. Several iterations of over-bend angle have been considered and analysed both by Finite Element Modelling and through lab based experimental tests. Figure 3: Offset bend tooling with 0o overbend.

The modelling of the tooling design is presented in the 2024 Annual report. The tooling illustrated in Figure 3 has no built-in over-bend. The required over-bend is applied through increasing the angle between the parallel and diagonal sections of the tooling. The fixed section (bottom part) of a tooling set with a 6° overbend design, is shown in Figure 4. The design in Figure 4a, shows the degree of over-bend relative to the horizontal axis of the conductor feed. However, experimental trials have shown that this approach of tooling design creates artifacts in the conductor feed, since the conductor is constrained either side of the tooling, which present in the wound coil. One solution is to rotate the whole press assembly by an amount equal to the required over-bend, such that the parallel faces of the tooling are parallel with the conductor feed. The press stage hardware has been modified to achieve this functionality. Alternatively, the over-bend is achieved by adopting the tooling profile shown in Figure 4b, where the angle of the diagonal section is increased

Figure 4: Fixed half of offset bend tooling for a 6o over-bend. 28

by the amount of over-bend required. A series of tooling has been produced, based on the profile shown in Figure 4b, with a 2°, 3°, 4° and 6° overbend tooling designs. Bend forming was trialled in three 4x4mm solid bar conductor samples, with 0.5mm corner radii and length 300mm, for each tooling design, using the press forming stage of the coil winding demonstrator. Consistent force was applied to all samples (estimated 3016N) with the same closing speed (of the tooling) to form the offset bends in the centre of sample length. Once pressed, the samples were placed in a tensile tester and 650N tensile force applied. The samples were then scanned in a 2D plane and image processed to find the centre line of the lead in, lead out and the diagonal section, as well as the mid-line through the conductor. The displacement / spacing of the lead out, relative to the lead in, and the gradient of the mid-section, can be compared against an ideal bend geometry and with other tooling designs, to inform the choice of tooling. An image processed CAD model of an ideal bend geometry is shown in Figure 5, and a sample pressed using the tooling set no over-bend, in Figure 6. Lab based trials windings have highlighted issues in the bend forming process, that introduce artefacts in the finished coil.

Figure 6: Scanned image of offset bend with no over-bend allowance.

Figure 7: Trial coils showing nested end winding (left) and active region (right).

Modifications to the press stage that forms the offset bends in the conductor feed have been implemented, to coordinate the travel of the upper part of the tooling, the conductor clamp, and the linear position of the coil former, to improve the wound coil geometry. The lab based winding trials are performed by hand 29

driving the splined shaft on the coil former stage using a crank handle. An automated inline tensioning system, independent of the winding machine is under construction, and commissioning is ongoing. However, to date, the trials have been performed with no applied tension on the conductor feed, other than the friction due to the rollers in the wire straightening process (~25N). Finite element mechanical modelling and analytical calculations estimate the maximum tension that can be applied to the 4x4mm solid bar conductor is between 650 and 700N. Trial windings on a 168mm length former, prior to removal from the former, are shown in Figure 7 and shows the layer change features nested in the end winding. The issue of spring-back is a consideration in both the forming of the layer change features and at every corner of the coil former, in the wound coil. As the former rotates, the conductor feed is formed around each 90° corner bend. However, without spring-back compensation the net angle that results in the conductor, when the coil is released from the former, is reduced. For example, if the bend on the former is 90° and spring-back accounts for 2.5°, the resulting net bend is 87.5°, once the coil is released from the former. The trajectory of the conductor is therefore tangential to the corner radius on the former, rather than parallel to the coil former sides. The accumulative effect of <90° bends on each corner, for each turn, causes the coil to splay out, when released from the former. This is illustrated in Figure 8. A trial coil wound on the former with no applied tension, is shown in Figure 9 and demonstrates the effect of spring-back accumulation within the coil. A secondary process can be applied to the wound coil on the former, to compensate for some of the inherent spring-back and improve the net coil geometry. Several approaches to this secondary process are under development and modelling activity is ongoing. The same coil geometry as in Figure 9, pressed on the active region of the coil, to introduce a level of overbend into the existing bends, is shown in Figure 10. The net geometry of the coil is significantly improved.

Figure 8: Ideal turn (left) and effect of 87.5° corner bends, when coil released from former (right).

Figure 9: Coil released from former without any secondary procressing.

Figure 10: Coil wound an then pressed (on sides) using a hydraulic press.

Additive Manufacturing of High-Performance Electrical Machine Windings Led by University of BRISTOL This work stream is structured around three key research areas enabled by the use of metal Additive Manufacturing (AM): namely, flexible winding design tools, electrical property measurements, and robust electrical insulation techniques, with the aim to optimise conductor geometry, standardise testing methods for the electrical conductivity and temperature coefficient of resistance in AM materials, and to develop high-performance insulation processes for complex winding geometries. Together, they enhance electrical efficiency, thermal performance, and durability, and offer a route to next-generation electrical machines.

MEASUREMENT PROTOCOL FOR ELECTRICAL PROPERTIES OF AM MATERIALS Traditional manufacturing has well-established electrical property benchmarks, ensuring material reliability and consistent performance. However, additive manufacturing introduces variability due to differences in feedstock, processing parameters, and post-treatment methods, leading to variation in the resulting material properties. For AM materials to gain wider adoption in electrical machine applications, standardised measurement procedures for electrical properties are essential to ensure consistency across different suppliers and fabrication techniques. Additionally, without reliable testing methods, it is challenging to evaluate the impact of AM process parameters on electrical performance, slowing down process parameter optimisation. This work package focuses on the development of a measurement protocol to determine electrical conductivity and the temperature coefficient of resistance of AM conductors. A standard serpentine specimen geometry, Figure 1, was designed to conform to ASTM B193 with a compact single-plane footprint. Resistance is measured using the 4-wire measurement method, Figure 2. A bespoke fixture was designed to hold the specimen in a vertical orientation, ensuring robust electrical contact and uniform exposure to externally supplied heated air, Figure 3. Two experimental setups were employed, with low and high current, Figure 4, to determine whether accurate measurements can be achieved using a more cost-effective and less complex system operating at lower current. The measurement protocol and experimental setup were validated, ensuring accurate comparison of the electrical conductivity of different tested specimens, Figure 5, and the temperature coefficient of resistance, Figure 6, evaluating the performance of different experimental arrangements. Additionally, guidelines for data normalisation and analysis are provided to ensure repeatability and reliability of the measured electrical properties. 31

Figure 1: Serpentine specimen geometry.

Figure 2: Schematic of the 4-wire resistance measurement setup.

Figure 3: Specimen fixture manufactured using 3D printer and PPS-CF material.

Figure 4: A high-current 4-wire resistance measurement experimental arrangement.

Figure 5: Normalised measurement electrical conductivity of tested specimens at 20oC.

Figure 6: Comparison of the temperature coefficients of resistance of tested specimen.

FLEXIBLE DESIGN TOOLS FOR ADDITIVE MANUFACTURING OF COILS Additive manufacturing offers unparalleled geometric flexibility, allowing optimised winding designs with varied cross-sections, integrated terminals, and embedded cooling systems. To fully exploit these capabilities, automated design tools are necessary. These tools facilitate rapid prototyping, design iteration, and optimisation while integrating with simulation and analysis frameworks and are well-suited to future machine learning techniques. An automated geometry generation tool has been developed to produce winding designs based on a given cross-section profile, Figure 8. This tool allows customisation of winding orientation, splayed profiles for manufacturing, active length adjustments, changes in axial taper (axial flux machines), and the integration of

Figure 7: Automated geometry generation tool with customisation capabilities. 32

cooling channels for direct thermal management, Figure 7. To further enhance cooling, these channels can be incorporated into multiple contiguous turns of the winding, Figure 9. Ongoing work focuses on integrating additional thermal management strategies into the design tools, such as end-winding heat exchangers and extended surfaces. An associated simulation framework will enable the quantitative comparison and optimisation of cooling features. Additionally, a conductor shape optimisation tool is being developed to generate winding geometries tailored to the specific electromagnetic operating environment and duty cycle.

Figure 8: Winding designs based on a given cross-section profile.

Figure 9: Cooling channels in multiple contiguous turns of the winding.

DEMONSTRATION OF ROBUST ELECTRICAL INSULATION UNDER REPRESENTATIVE OPERATING CONDITIONS The geometric freedom of additive manufacturing enables the realisation of novel, complex conductor geometries. However, for these new designs to be widely adopted, their electrical insulation must be robust when subject to representative operating conditions. Insulation coating is particularly challenging due to the inherent surface roughness, porosity, and oxidation of additively manufactured substrates, in addition to the complex geometry. This work package focuses on developing post-processing techniques to control AM surface roughness and application of high-performance insulation systems tailored for AM windings, Figure 11. Automation systems 33

have been developed to ensure coating quality and repeatability, necessary for commercial adoption, Figure 10. Powder coating, liquid spraying, and liquid dip coating methods are experimentally evaluated by comparing additively manufactured samples with commercially available electrical copper.

Figure 10: Custom-built robot with multiple degrees of freedom for automated insulation processes.

Ongoing work explores PEEK insulation for complex winding geometries, taking advantage of its hightemperature tolerance and dielectric properties. As a thermoplastic, PEEK can be separated from the metal substrate (above the melting temperature), offering a reworkable insulation system. Initial trials using electrostatic spray coating, Figure 12, showed good adhesion and coverage, with ongoing efforts to refine coating thickness controllability and breakdown voltage.

Figure 12: Electrostatic spray PEEK coating trials.

Figure 11: Insulated conductors with different geometries.

2.3: Manufacturing technologies for flexibility and customisation Led by AMRC Grand challenge 2.3 aims to develop manufacturing processes which are more flexible to changes in demand and design which might also open new design opportunities. Research has focused on the use of industrial robots as the basis of coil winding systems, and on remote laser processing of electrical steels.

Remote laser processing Remote laser processes are proposed as an alternative to conventional laser systems. In these processes, a high-brilliance laser is steered across the workpiece at several meters per second using a high-speed galvanometer. The combination of scan speed and power densities of 107– 1010 W/cm2 means the steel is partially vaporized. This vaporized fraction then assists material removal by ejecting the molten fraction from the kerf to a depth of tens of microns. The full sheet is then progressively cut over multiple passes. At the start of the year, the GC2.3 team supported a study led by Dr Luke Jones and Prof. Hassan Ghadbeigi at the University of Sheffield, which showed that the process parameters for remote laser cutting had minimal influence on the bulk mechanical properties. There was an observable increase in edge hardness with increasing power, and an impact on fracture strain attributed to residual stresses at the cut edge and crack initiation due to surface roughness. (https://doi.org/10.1016/j. jmmm.2024.172400) The GC2.3 team was then joined by Dr Daniele De Gaetano, who has led experimental work on remote laser processing. Building on previous research exploring the parameter space of scan speed and power, Dr De Gaetano has focused on the importance of time between scans and the impact on magnetic properties. It has been observed that there is a “sweet spot” around 400 ms between scans, where the resulting magnetic properties compare favourably to electrical discharge machining. A high-speed thermal imaging camera is currently being used 35

to understand if this corresponds to a characteristic cooling rate of the material in the experimental setup. A manuscript is currently being prepared for submission to a journal in the near future. In relation to phase two, Dr De Gaetano has investigated the feasibility of deliberately inducing thermal degradation to write patterns in the magnetic properties of the steel without removing material. Magnetic characterization showed that the permeability could be modified with laser treatment; however, using computer simulation of a synchronous reluctance machine, it was shown that this could not be done to a useful degree. The remote laser processing cell developed as part of the EPSRC FEMM hub is now being upgraded with a 2 kW, 200 ns pulse laser emitting in the near-infrared range, funded by the High Value Manufacturing Catapult. Research in the final year will firstly evaluate the impact of this new pulse laser in cutting processes, before exploring its use in micro-drilling or perforating the steel to create flux barriers and other features.

Robotic coil winding Industrial robot manipulators can be adapted to a wide range of applications and have been demonstrated in electrical machines manufacture in magnet placement, coil insertion and lamination stacking. Within grand challenge 2.3 industrial robots have been used as the basis for a flexible needle winding system which can be adapted to a wider range of winding schemes and machine geometries than a traditional needle winding machine. This year, Gianmarco Pisanelli, who has led research on robotic coil winding within the Hub has been promoted to Technical Fellow in Novel Robotics. Consequently, Mr Pisanelli has stepped-back from the hub activities after concluding experimental work on in-process measurement of tension fluctuations during needle winding. The wire tension was measured using a multi-axis load cell mounted behind the stator tooth. The speed of the wire being drawn from the tensioning system was calculated from the reported position of the robot. It was observed that the trajectory at the corners of the stator tooth resulted in points where the wire speed momentarily reversed, with a corresponding drop in the force acting on the load cell as some of the wire tension is relieved. This is a consequence of the rectangular path in needle winding, which in a normal machine might be compensated somewhat by a dancer arm within the tensioning system. Aside from these fluctuations due to the winding trajectory, the reported position of the robot was found to be insufficiently accurate to reliably predict other minor fluctuations in wire tension to allow closed-loop control in this application; however, it has suggested how the robot might be used with a conventional winding machine to minimize fluctuations.

Figure 1 Free wire length (FWL) calculated between robot position and contact point of wire on the tooth (a), calculated wire velocity indicating instances where the velocity drops (b) and corresponding points where the tension on the wire is relieved (c).

Cross cutting themes A central thread of activity linking our research outputs

Cross cutting (X) themes underpin out Grand Challenge themes. Each theme incorporates elements each of the X theme in order to develop a deeper understanding and maximise FEMM Hub outputs. X1: Sustainable manufacturing of electrical components for the circular economy. X2: In-Process tracking and tracability for zero-defect manufacture of electrical machines. X3: Roadmapping and technology reviews. X4: Demonstrator.

X1: Sustainable manufacturing of electrical components for the circular economy Led by NMIS GC X1 is a cross-cutting theme within the FEMM hub focused on the sustainable manufacture of electrical machine components, with a view to implementing circular economy strategies. Sustainability is a key component of any future machine design, and as such, this Grand Challenge was updated to be a crosscutting theme of all FEMM hub work packages. This will ensure that a clear focus is given to the sustainability of future electrical machines. This work package aims to: • • • •

Reduce use of finite materials in next generation of machines and enable recapture cycles to reuse materials Give consideration to energy efficient manufacturing Implement Design for Disassembly strategies for future electrical machines, including opportunities for reuse, recycle, remanufacture etc Develop a circular economy approach for an electrical machine supply chain that uses data driven intelligence based on product data

Current electrical machines are manufactured using a linear economy model but need to change to a circular economy (CE) approach, as shown in Figure 1 (L). Adopting a circular economy approach does not dictate one solution to solve all the issues, but is an alternative way of approaching the problem, and provides many solutions that can be adopted. Often, when “sustainability” is mentioned within the engineering community, the first response is often linked to recycling material. Although recycling of materials will be an important factor in the drive towards circularity, it should not be considered the first or only solution. The circular economy hierarchy is shown in Figure 1 (bottom), and is a ranked order with the most favourable solutions at the top, i.e. those that require less energy consumption and material usages, and the least favourable solutions at the bottom. Grand Challenge X1, in conjunction with PhD student Leigh Paterson, has been looking at ways of quantifying the various issues around current production and through-life management of electrical machines. “The Juxtaposition of Our Future Electrification Solutions: A View into the Unsustainable Life Cycle of the Permanent Magnet Electrical Machine” [1] was published in Sustainability, and gave an overview of the typical life cycle of permanent magnet electrical machine as it stands today, and demonstrated the environmental issues associated with the current linear life cycle. For electrical machines to be a truly

Figure 1: Circular Economy model (top) and the Circular Economy hierarchy (bottom).

sustainable solution, improvements need to be made from material sourcing, through manufacturing, to design for disassembly. Alternative practices are discussed in the paper, with the short term aim to ease the immediate environmental burden of these products, and the ultimate aim to design and manufacture fully sustainable electrical machines. PhD student Prithvi Bhagat was lead author on the paper “A Methodology to Assess the Sustainability of E-motors in Electric Vehicles” [3], which was presented at the IEEE International Conference on Electrical Systems for Aircraft, Railway, Ship Propulsion and Road Vehicles & International Transportation Electrification (ESARS-ITEC). A challenge for the automotive industry in the Figure 2: Hollow coil modules, as designed in GC2.2, will be used as a demonstrator for a short term is the balance of more sustainable solution for winding resin impregnation sustainability while meeting performance criteria, including weight reduction. This paper developed a life cycle mapping to understand the end of life scenarios of subcomponents for an in-wheel electric motor, and created a methodology, including a ranking system based on the current design of such a motor, plus the scope for improvements in design and manufacture that will lead to opportunities for sustainable electric motor design.

Another work stream has been the development of over-moulded coil modules. The aim of this work is to use injection moulding to manufacture modular windings that are optimised for disassembly and repair. Current manufacturing and assembly techniques often use bulk impregnation for the coil windings, which cause issues for repair or replacement of the windings, and this work stream is aiming to remove the need for bulk resin impregnation, instead focusing on localised containment that is optimised for end of life processing.

FIgure 3 - Circular techniques and their relationship to product value (L) and remanufacture value (R)

The work stream is linked to the ongoing research in GC2.2 and will utilise the module design of the hollow coils as shown in Figure 2. Remanufacture is a topic of interest for electric motor manufacturers, but there is still a lot of unknowns in terms of business case, economic impact, and technical interventions that could make it a practical solution in the short term. GC X1 has launched a work stream that will focus on outlining the benefits and limitations of implementing remanufacture for high value electrical machines. As shown in Figure 3 above, there are several circular economy principles that can be implemented into the design of future components, and they will each have a different impact on retained product value. Understanding the tipping points that make individual implementation strategies profitable is a key driver for businesses to adopt circular processes, and identifying the design metrics that could be implemented to make remanufacturing more attractive, considering cost, manufacturability, and product efficiency will be the focus of this work stream.

[1] Paterson, L.; Miscandlon, J.; Butler, D. The Juxtaposition of Our Future Electrification Solutions: A View into the Unsustainable Life Cycle of the Permanent Magnet Electrical Machine. Sustainability 2024, 16, 2681 [2] Ruddell, Tom & Karkasinas, Aineias. (2021). Justification for remanufacture in the lighting industry [3] P. Bhagat, C. Jones and J. Miscandlon, “A Methodology to Assess the Sustainability of E-motors in Electric Vehicles,” 2024 IEEE International Conference on Electrical Systems for Aircraft, Railway, Ship Propulsion and Road Vehicles & International Transportation Electrification (ESARS-ITEC), Naples, Italy, 2024, pp. 1-6

X2: In-Process tracking and tracability for zero-defect manufacture of electrical machines Led by UNIVERSITY OF SHEFFIELD The tracking and traceability of manufacturing processes remain essential for improving quality, efficiency, and cost-effectiveness across industrial applications. These advancements have been increasingly driven by digitalization, leveraging sensors, machine learning, and data integration into high-fidelity models or ‘Digital Twins.’ The manufacture of electric machines is a highly complex process, involving a combination of traditional machining, forming, and cutting techniques alongside intricate assembly and testing workflows. As we continue into the final phase of our research, we have continued to refine our sensorised workstations, with a particular focus on coil winding and thermo-crimping processes. Our work on digital twin modelling has evolved to include finite element analysis (FEA) for coil winding, allowing for a deeper understanding of wire tension, stress distribution, and deformation effects. In parallel, we have expanded our research into action recognition within manufacturing, developing enriched datasets and multi-modal sensing techniques to improve the identification of human actions in both production and end-of-life remanufacturing activities. Collaboration remains a key aspect of our research strategy. We continue to work alongside partners such as the AMRC to explore high-speed processes in electric motor (EM) manufacturing while also engaging with the X1 cross-cutting theme on sustainability and circular economy initiatives. Through these efforts, we aim to enhance digital manufacturing intelligence, ensuring greater efficiency, adaptability, and sustainability in electric machine production and lifecycle management.

Process monitoring through digital twin The ongoing digitization of electrical machine manufacturing processes continues to drive our research, particularly in the development of predictive and monitoring capabilities using Digital Twin (DT) models. This work has evolved from past efforts in process characterization—such as wire placement tracking using deep neural networks—to a more detailed analysis of the underlying mechanics of coil winding and forming. A crucial aspect of electric machine longevity remains the precision of coil winding, where variations in wire tension, bending forces, and placement accuracy can significantly impact long-term performance. Our latest research focuses on refining the physics-based modelling of these processes, using finite element analysis (FEA) to simulate wire deformation under varying tension forces as shown in figure 1. By integrating these simulations with real-time data acquisition from sensorised winding setups, we aim to create a DT 41

framework capable of capturing and analysing wire stress, velocity profiles, and potential failure points during the winding cycle. The ability to simulate different process conditions, such as variations in tension and winding patterns, enables us to assess their influence on coil integrity and predict potential defects before they occur as seen in figure 2. Looking ahead, our DT system is being developed to provide manufacturers with deeper insights into the coil winding process. By incorporating machine vision data and advanced simulation profiling, we can model how process and material parameters, such as wire gauge, insulation properties, or bobbin design, affect the final coil structure. The ultimate goal is a predictive, real-time system that not only characterizes and optimizes the winding process but also provides actionable feedback to improve quality and reliability in electric machine manufacturing.

Figure 1: A FEA simulation and analysis of wire bending during a single revolution for two different acting tension forces. (L) ANSYS model deformations for both 25N and 1N tension forces, along with corresponding wire stress and velocity plots (R).

Figure 2: A Digital Twin (DT) simulation for a coil winding process around a square bobbin. (Above) Given certain process parameters we can simulate and vary the forces to induce loose wires (yellow) or correct wire placement (green). (Below) shows examples of our simulation parameter profiler in our DT to allow us to evaluate the impact of different settings on coil winding performance. 42

Connections and Terminations: Thermal Crimping The sensorised thermal crimping system was further developed to understand the correlation between the machine and the process parameters and their impact on the final quality of the terminations. The RGB vision system captured data during, before and after the crimping operation to monitor any visible defects/ deformities in the termination and the wear in the electrodes. The infrared camera recorded data during the crimping operation to capture any hidden defects that were not visible using vision systems. As suggested by industrial partners from the aerospace sector, the focus was on preparing terminations on Litz wires which are particular types of multistrand wires required to operate effectively at higher temperatures, for example in aerospace applications. The experiments proved that it was possible to make strong and reliable connections on Litz wires utilising the thermal crimping system. The electrical properties of the terminations were confirmed by conducting resistance measurements using a highly accurate micro ohmmeter and the connectivity of the wires was confirmed by achieving 100% connectivity in all the strands of the wires using a multimeter. The thermal characteristics of the terminations were confirmed by observing the thermal profile of the terminations during manufacture and any visible defects were checked during the process by using attached vision sensors. The mechanical strength of the terminations will be checked using the force pull-out testing.

Figure 3: (a- L) The images obtained from vision sensors and infra-red cameras during the thermal crimping operation (b - R) Thermally crimped Litz wire terminations.

To achieve the goal of in-process quality inspection of terminations using vision sensors, RGB image processing algorithms were developed to assess the accuracy of the footprint of the electrode and any wear in the electrodes. The system processed live feeds from an Intel RealSense Depth D405 camera. The results suggested improved accuracy and efficiency by combining cyan and saturation channels that yielded a higher true positive rate in object detection. The RGB image data was utilised for investigating deep learning techniques for in-process quality inspection of the terminations. A massive bottleneck in deploying deep learning for quality inspection in manufacturing operations is the unavailability of training data required to develop an effective model. Data augmentation techniques offer a solution by increasing the size and diversity of the training dataset. A review of the literature revealed a gap in knowledge regarding the choice of an image augmentation technique and the reasoning behind the choice. This research proposed a framework for choosing an appropriate augmentation method in various scenarios. It was achieved by investigating pixellevel transformations in the context of data augmentation to enhance the training performance of quality inspection in scenarios with extremely limited data. Firstly, the effects of four pixel-level transformations on YOLOv7 and SSD real-time detectors are analysed. Secondly, the augmentation effect transferability across dissimilar datasets is discussed. Lastly, a framework is proposed for choosing the appropriate augmentation method in various scenarios. The results show that the proposed framework provides consistent results with an average improvement of up to 35% in meanAP and a reduction of 50% in the classification loss for the electrical wires terminations dataset. 43

A new mathematical equation was developed to calculate a crimping score for every thermally crimped termination based on the user’s input parameters such as applied current, pressure and cycle times. This crimping score facilitated a better correlation between input parameters and the thermally crimped product characteristics. Figure 4 (a) shows the correlation between the melted insulation residue outside the lug and the crimping score, and (b) depicts the correlation between the crimping score and the shape of the footprint of the electrode. The shape of the footprint of the electrode and the region of insulation residue are key markers of the quality/goodness of the termination.

Figure 4:(a - L) The correlation between the melted insulation residue outside the lug and the crimping score, and (b - R) The crimping score and the shape of the footprint of the electrode.

The current focus of the research is on further development of the in-process inspection system for the crimping process by integrating the RGB data and infra-red data from the crimped terminations along with the experimental data on the process or machine parameters. Three ML models (SVM, RF, and LSTM) are being developed and tested for robust prediction before each crimp operation. The developed system will be capable of predicting either product quality features from process parameters or process parameters from product quality features.

Enhancing Action Recognition for Manufacturing and End-of-Life Processes Action recognition is a growing area of machine learning that focuses on classifying and identifying specific human actions within a scene or video. While widely applied in sports analytics and medical monitoring, its potential in manufacturing is becoming increasingly evident, particularly for tracking assembly tasks, improving human-machine collaboration, and optimizing training. However, unlike controlled environments where actions are clearly defined, manufacturing—especially in end-of-life processes like repair, remanufacturing, or disassembly—presents unique challenges. The variability in product condition, operator skill level, and even tool use introduces ambiguity in recognizing actions, making traditional action recognition approaches less effective. For instance, distinguishing between an operator prying open a casing versus unscrewing a bolt can be difficult if the action is partially obscured or executed differently across workers. To address these challenges, we have developed a methodology to enhance action recognition in manufacturing by enriching datasets with detailed activity annotations. Traditionally, video clips are labelled with a single classification tag, such as ‘Put’ for placing a component. Our action-recognition ontology figure 5 expands this by incorporating additional descriptors, including tool use, part condition, operator experience, and environmental influences. By encoding these attributes as binary one-hot features, we enable deep neural networks (DNNs) to learn more nuanced distinctions, improving recognition accuracy in complex, real-world scenarios.

Figure 5: An action-recognition based ontology for end-of-life activities (top) allows for richer detail to be captured, such as tool use or part status (middle) and then used as additional binary one hot encoded features for better training of DNN models (bottom).

To validate this approach, we have begun constructing a new action recognition dataset focused on an electric machine manufacturing use case, thermo-crimping of Litz wire, using our sensorised rig shown in figure 6. The process has been decomposed into both preparatory steps and core operational tasks, capturing a multi-modal dataset that includes macro-level machine interactions and micro-level hand manipulations. By integrating diverse sensing modalities, such as vision (RGB/depth), inertial measurement units (IMUs), and electromyography (EMG) for muscle activity—we can compensate for the limitations of any single modality. For example, while vision effectively captures hand movements, EMG sensors provide insights into grip force and hand posture, which are particularly useful when visual data is ambiguous or occluded. Figure 7 illustrates this, showing that while EMG outputs for simple wire manipulation and forceful cutting actions appear similar, combining them with depth and vision data allows for more accurate action differentiation. Beyond improving real-time monitoring in manufacturing, this research aligns with the broader push for sustainable and circular economy principles. Understanding human actions in both assembly and end-of-life operations, such as remanufacturing and repair, will be crucial in automating and optimizing Re-X (reuse, repair, remanufacture, recycle) pathways. By leveraging machine learning and multi-modal sensing, we aim to create robust action recognition models that can not only improve manufacturing efficiency but also facilitate intelligent decision-making for the disassembly and reuse of electric machine components.

Figure 6: Thermo-crimping use case broken down into the main steps of both preparatory sequences and main operations (above). This includes multi-modal sensor capture at each step, including wide view for macro actions and close view for micro actions (below).

Figure 7: Multi-modal sensing data, either from vision (RGB / Depth) or IMU or EMG (muscle contraction) can help in differentiating similar actions during a manufacturing process. Here the EMG data for both simple litz wire manipulation or cutting of the wire look similar in output. However, we can utilise vision to better help identify the correct action being undertaken.

X3: Roadmapping and technology reviews Led by UNIVERSITY OF STRATHCLYDE The FEMM Hub has an aim of putting UK Manufacturing at the forefront of the electrification revolution. That electrification revolution is being accelerated by the global drive towards decarbonisation and the replacement of incumbent combustion based technologies for power generation and transportation with electrically powered alternatives. This transformation is the subject of legislation through the 2019 Climate Change Act, which mandates the transition to net zero by 2050 in the UK. The roadmap and the analysis which underpins it, the FEMM Hub investigators, researchers and industrial partners have aimed to explore what this transition to net zero means for future electrical machines manufacture, and to use this timebound driver as the end point of a roadmap. The transition to net zero creates a set of requirements on the electrical machines industry. NEED 1: Make machines better so they perform better NEED 2: Make manufacture more efficient NEED 3: Secure supply of critical materials NEED 4: Flexibility and scalability to meet demand While it is clear that there are many uncertainties due to the development of future products, business models, and behavioural responses to the net zero challenge, we can begin to articulate a set of issues around material supply and demand and sustainability, which have been initiated by the hub and which need to be extended through future research. • Post launch of the hub, a cross cutting theme on circular economy was initiated. It is essential that this focus is maintained and embedded across the programme. • Identifying sector-based demand for electrical machines is subject to large sources of uncertainty, and therefore attempts to determine likely criticalities in terms of material supply is at least equally difficult. There would be value in instigating a focused activity with a view to providing a flexible / dynamic model material supply and demand based on available assumptions. • Irrespective of the set of planning assumptions made, it seems inevitable that demand for high performance electrical machines is likely to increase aggressively in the coming years. Future manufacturing needs to be capable of dealing with this growth, and of being flexible and adaptable to the uncertainty in demand. The roadmap can be downloaded by visiting the FEMM Hub website - https://www.electricalmachineshub. ac.uk/roadmap.

X4: Demonstrator Led by Newcastle University We are building a set of demonstrator machines which will allow us to compare experimentally a benchmark machine with sets of machines using the advanced manufacturing techniques the hub is investigating. With so many industrial partners involved in the hub, selecting the correct machine specification has promoted debate. Several partners would like to use their own specification but have understandable reservations on publishing commercially sensitive details. To overcome this, we have selected the well published USDA FreedomCar 2020 specification as our baseline for comparison. This also gives us the additional benefit of a wider body of research carried out around the FC2020 specification to compare our work to. The FC2020 specification is for light electric vehicles operating at 30kW continuous and 50kW peak power and speeds of up to 14,000rpm. Efficiency needs to exceed 95% across a wide operating range. The major design points are shown in the table below. As a benchmark for experimental comparison, we are constructing two machines using standard techniques; a distributed winding and a single tooth (concentrated) winding version. We will then build variants of these using new manufacturing techniques and topologies. The stator and rotor are currently being manufactured by Midland Tool & Design. The liquid cooled case and shaft being are being manufactured at Newcastle University. Rated Power/torque/speed

30kW (continuous) 2,800 rpm/ 102Nm 14,000rpm / 20Nm

Short-term peak Power/torque

55kW (for 18 seconds) 2,800rpm/187 Nm 14,000rpm / 38Nm

Efficiency@20Nm 2800rpm-14,000rpm >95% Maximum diameter / length

250mm /200mm

Maximum mass

35kg

Distributed winding (top) and single tooth windng (bottom)

Torque-speed and efficiency characteristics

The outer jacket cooling spiral 48

ALLIGned Projects

From nominal core properties to in-service performance Led by University of Sheffield Impact of neglecting the gap caused by laser cut on the edge damage effect The models of the edge damage effects on permeability and core loss density reported in the past FEMM Hub annual reports assumed the permeability and core loss density functions across any thin slits are continuous considering the slit width is much smaller than the sample width. First, this report validates that the error caused by the above assumption is negligible, by developing a discontinuous edge damage effect model followed by the comparison of the core loss density distribution between the continuous and discontinuous models. The measured laser cut slit width with a Keyence VHX-100K microscope is approximately 30μm, as shown in Fig. 1. Hence, a 30μm gap, corresponding to an air region instead of iron core region, was introduced in the normalised hysteresis loss function as illustrated in Fig. 2. The normalised hysteresis loss function was derived from the edge damage effect model reported in the last annual report [FEM24]. Then, Fig. 3 compares the derived normalised hysteresis loss distributions at 1T, with and without considering the 30μm gap due to laser cut slit, for both 3-slit and 4-slit strips. It can be observed that the impact of the 30μm gap on the hysteresis loss distribution is negligible, and hence the normalised hysteresis loss function with respect to the distance across the strip can be assumed as a continuous function.

Figure 1: Laser cut slit width measurement using Keyence VHX-100K microscope.

Figure 2: Derived normalised hysteresis loss distribution for 1-slit strip at 1T. 50

Figure 3: Derived normalised hysteresis loss distribution at 1T, with and without considering the 30μm gap due to laser cut slit. (a) 3-slit strip. (b) 4-slit strip.

Edge damage effect on machine level core losses due to laser cut Given that the Altair Flux2D finite element analysis (FEA) tool does not support distance-dependant permeability and hysteresis loss coefficient, a layered-core FEA model, as illustrated in Fig. 4, was developed to quantify the edge damage effect on machine level core losses due to laser cut. The stator tooth and backiron regions are split into 50 layers while the stator tooth tip region is represented by 19 layers, with 0.1mm thickness per layer. Each layer has its own BH curve and hysteresis loss coefficient. In this case, by varying the BH curves and hysteresis loss coefficients based on the layer’s distance to the cut edges, the developed edge damage effect model reported in [CHE23], [FEM24] can be implemented into an electrical machine FEA model to quantify the edge damage effect on the core losses at a machine level. Fig. 5 shows a series of BH curves at various distances to the cut edge, derived based on the model in [CHE23]. Note that the BH curves shown in Fig. 5 are only for demonstration of the variations of the DC magnetisations while the layered-core FEA model requires 50 different BH curves for this design.

Figure 4: Machine FEA model with layered-core.

Fig. 5. BH curves at various distances to the cut edge.

By performing the field solutions in FEA, flux density distributions with and without considering edge damage effect at 205Nm are compared in Fig. 6. The flux densities are capped to 2.5T for both graphs to compare in the same range. It can be observed that after considering edge damage effects on the permeability (or BH curves), the flux density in the stator core is redistributed. By subtracting the flux densities in Fig. 6(a) from those in Fig. 6(b), Fig. 7 shows the flux density difference between with and without edge damage effects. The flux density difference ranges in Fig. 7 are set to [-0.5, 0.5] T to avoid the disturbance caused by localised error. Overall, the flux densities reduce near the edge area and increase in the central area, after accounting for the edge damage effect on the permeability of the stator core.

Figure 6: Flux density distributions at 205Nm. (a) Without edge damage effect. (b) With edge damage effect.

Figure 7: Flux density difference between with and without edge damage effects at 205Nm.

Subsequently, the nodal flux densities and the node-element tables are used in the post-process to calculate the core losses. Three scenarios are considered in the core loss calculations, including (a) no edge damage effect; (b) with edge damage effect on permeability only; and (c) with edge damage effect on both permeability 52

and core loss. In Scenario (b), the hysteresis loss coefficients without edge damage effect are used while the edge damage effect on the permeability is considered. Fig. 8 compares the core loss density distributions for the above three scenarios at 205Nm, 10,000r/min. It can be seen that Scenarios (b) and (c) have similar distribution patterns in their core loss density plots while both of them have distinct differences from Scenario (a), which is caused by the flux density redistribution due to edge damage effect on permeability. Meanwhile, Scenario (c) exhibits higher core loss densities than Scenario (b), indicating that the overall core loss increases after considering the edge damage effect on the core loss (or hysteresis loss coefficient).

Figure 8: Core loss density distribution at 205Nm, 10,000r/min, with three scenarios: (a) no edge damage effect; (b) with edge damage effect on permeability only; (c) with edge damage effect on both permeability and core loss. Unit: W/m3

Fig. 9: Core loss density difference distributions at 205Nm, 10,000r/min. (a) Difference between with edge damage effect on permeability only and without. (b) Difference between with edge damage effect on permeability only and that with edge damage effects on both permeability and core loss. (c) Difference between with and without edge damage effects. Unit: W/m3. 53

Fig. 9 shows the core loss density difference distributions at 205Nm, 10,000r/min. Figs. 9(a), 9(b) and 9(c) are obtained by subtracting Fig. 8(a) from Fig.8(b), subtracting Fig. 8(c) from Fig.8(b), and subtracting Fig. 8(a) from Fig.8(c), respectively. From Fig. 9(a), it can be seen that the core loss densities decrease on the edges but increase in the middle of tooth and middle of back-iron, after accounting for the edge damage effect on the permeability. This trend is consistent with that in the flux density difference shown in Fig. 7. Whether the overall core loss increases or decreases cannot be seen from Fig. 9(a) and it needs an integral of the core loss density over the stator volume, which will be presented later. From Fig. 9(b), it can be observed that all the core loss density difference values are negative. It means if neglecting the edge damage effect on core loss while only considering the edge damage effect on permeability, the core loss will be underestimated. Fig. 9(c) shows that overall, the core loss densities increase after accounting for edge damage effects on both permeability and core loss. On some edges, the core loss densities reduce. This is caused by flux density reduction due to the flux redistribution effect. After integral of the core loss densities over the stator core volume, Table I compares the core losses between the three scenarios presented in Fig. 8. The percentage numbers in Table I are calculated by taking the scenario of no edge damage as the reference. It can be seen that if only accounting for the edge damage effect on permeability, the hysteresis loss is 1.9% lower than that without considering edge damage effect. This number is 1.2% for the total core loss. Hence, the flux density redistribution influence, due to edge damage effect on permeability, on the core loss variation is negligible. On the other hand, if accounting for the edge damage effect on both permeability and core loss, the hysteresis loss and total core loss increase by 23.8% and 13.7% respectively. Therefore, the edge damage effect on core loss is non-negligible, and the main cause is the edge damage effect on the hysteresis loss rather than the permeability.

Item

No edge damage With edge damage With edge damage effect on effect on permeability both permeability and core only loss

Hysteresis loss (W) Eddy current loss (W) Excess loss (W) Total core loss (W)

318.4 219.8 10.5 548.7

312.2 (-1.9%) 219.4 (-0.2%) 10.4 (-1.0%) 542.0 (-1.2%)

394.3 (+23.8%) 219.4 (-0.2%) 10.4 (-1.0%) 624.1 (+13.7)

Table I: Machine level stator core loss comparison at 205Nm, 10,000rpm operation point.

Given that the FEA results are obtained based on the field solutions in the discretised nodes and elements, the accuracy of the proposed layered-core FEA method is not necessarily lower than that of the FEA tool which supports distance-dependant permeability and hysteresis loss coefficient, as 0.1mm thickness per layer in the proposed model imposes a much denser mesh than that of a conventional FEA model of an electrical machine, with the expense of more computation time. REFERENCE

[FEM24] Future Electrical Machine Manufacturing Hub Annual Report 2024, https://www.electricalmachineshub.ac.uk/outputs/ reports [CHE23] X. Chen, H. Wu, J. D. Ede, G. W. Jewell, L. M. Jones, and H. Ghadbeigi, “A model to account for magnetic permeability changes resulting from edge damage caused by laser cutting in a high performance cobalt-iron alloy,” Journal of Magnetism and Magnetic Materials, Volume 584, 2023.

Influence of cut edge damage on mechanical and magnetic properties in electrical machine laminations Led by University of Sheffield Objectives • •

Development of a finite element (FE) model for the thin sheet blanking process of 3.2% Si-steel. Implementation of a material flow model into Abaqus, integrating non-local effects.

Fig. 1: (a) Finite element meshed assembly of part instances in Abaqus (b) Simulation of thin-sheet cutting under shear and fracture mechanisms (c) Flow stress variation for different flow models (d) Characteristics of the cut edge in thin-sheet blanking.

Results and Discussion Blanking is a high-speed shearing process used to cut thick/thin sheets into precise shapes. During this 55

process, the material undergoes severe plastic deformation under high strain rates, leading to localized stress concentrations. Traditional finite element models often fail to capture microscale effects such as strain gradient hardening and grain boundary interactions, which significantly influence material behaviours. Therefore, user subroutine code was implemented with FE tools Abaqus to improve the accuracy, allowing for better insights into deformation mechanisms. Fig. 1(a) illustrates the assembly mesh model of the part instances. In the cutting zone of the sheet, the mesh was refined to enhance the propagation of fracture mechanics. Fig. 1(b) depicts the progression of the shear and fracture zones during the thin sheet blanking process. The variation in flow stress with plastic strain is shown in Figure 1(c). Model 3 exhibits higher flow stress due to grain boundary strengthening and the strain gradient effect which was implemented in the FE tool using user subroutine code. The thin sheet blanking process occurs in three stages. Stage 1 involves roll-over, where the sheet bends initially. This is followed by shearing, which takes place under intense shear localisation. Finally, cracks nucleate and propagate in the fracture zone, leading to the separation of the sheet. The simulated cut edge and the SEM image of the cut edge are presented in Figure 1(d). Fig. 2(a) shows the equivalent strain distribution before fracture, measured using digital image correlation (DIC) techniques. The simulated equivalent strain was validated with experimental results, showing a deviation of 3%. During the cutting process, shear band localisation was observed, as depicted in the simulation, where shear strain was concentrated in the narrow zone (Fig. 2(b)). The experimental SEM image confirmed that shear strain localisation resulted in a smooth surface aligned with the cutting direction. In the fracture zone, micro-voids were identified, serving as initiation sites for crack nucleation and subsequent fracture. The cut edge characteristics along the thickness direction reveal that the sheared surface appears smooth and reflective, followed by a fracture zone with a rough, matte texture, which is undesirable (Fig. 2(c)). The predicted residual stress after blanking indicates that tensile residual stress is induced at the surface shown in Fig. 2(d). During cutting, the sheet undergoes compression and shear, but after separation, the cut edge relaxes, transitioning into a tensile stress state. The shearing zone exhibits high residual stress due to severe plastic deformation.

Figure 2: (a) Model validation of equivalent strain distribution before fracture (b, c) Cut edge characteristics and qualitative comparison of simulation with experimental results across the section and along the thickness (d) Predicted residual stress distribution in different zones.

Geometrically necessary dislocations (GNDs) accommodate plastic deformation gradients, particularly near material interfaces and grain boundaries (Fig. 3(a, b)). A high GND density intensifies shear localization, forming shear bands and influencing surface hardness. Fig. 3(c, d) presents average GND variation with blanking speed and nano-hardness, validated with experimental measurements. The GND maps indicate severe deformation at the cut edge, where increased dislocation generation compensates for plastic deformation at higher cutting speeds. Limited time at high speeds restricts dislocation movement and recovery, leading to greater dislocation density near the sheared edge. Errors between simulation and experiment may stem from material property variations and numerical approximations. Surface hardness is highest at the cut edge and gradually decreased with distance due to reduced strain hardening.

Fig. 3: Distribution of GNDs at the cut edge, (a) experiment and (b) simulation (c) Experimental validation of average GNDs at different blanking speeds (d) Nano-hardness validation of cut edge samples.

Future work • •

Modelling the impact of magnetic loss during the thin sheet blanking process. Modelling the effects of coatings on thin-sheet blanking.

new for 2024/25

PhD STUDENTS

PhD title: A novel manufacturing method for application of ultrathin sheet laminations for electrical machines.

Nacho BlANCO AMRC

Nacho’s PhD research aims to enhance the efficiency of electrical machines by utilising thinner electrical steel laminations. The project delves into the challenges of producing cost-effective laminations that optimise power-to-weight ratios for future generations of electrical machines. Specific challenges include minimising cutting damage, electrical losses, and changes in magnetic properties occurring during the blanking process.

Nacho earned a BEng and MSc in engineering from Mondragon University in 2004, followed by an MBA in Industrial Management from Sheffield Hallam University in 2005. Since joining the University of Sheffield’s Advanced Manufacturing Research Centre (AMRC) in 2010, Nacho has been involved in project management. Through his PhD work, he also contributes to the AMRC’s team and developments in electrical machines.

PhD title: Developing digital twin and digital product passports for high-value electric machines to support their end-of-life decisions David studied and graduated with a MEng in Mechatronics & Robotics Engineering at the University of Sheffield in 2016. He then returned to the university in 2019 as a Research Assistant as part of the Digital Manufacturing research group. There he was involved in a variety of projects related to the collection and processing of information David Miller related to industrial processes with the goal of better University of Sheffield understanding those processes. This required working with industrial partners, developing custom software tools and testing them on production data. Several of these aligned with his personal research interests in image processing, frequency analysis and event cameras. In 2025, he started his PhD in developing a digital passport system to provide tracking and traceability for electrical machine parts which are used in a wide range of products. This is important as information on the product life cycle can be used to improve future versions of it and tracking is needed to better understand product use cases. Additionally it provides a list of users to contact in the event of a recall. 58

Digital technologies for process monitoring during manufacture of terminations in electrical machines Recent electric machine (EM) manufacturing advances have heightened the demand for high-quality products while pushing precision and durability limits. Although established quality inspection methods (e.g., end-of-line (EoL) tests) are beneficial, they often detect defects too late in the production process. This research project aimed to address this gap by developing a framework for inprocess defect detection—specifically for thermal crimped terminations—using a dual-modal sensing and machine learning approach.

Ioan-ALexandru Herdea University of Sheffield

Firstly, two complementary sensing techniques, RGB and Infrared (IR), were combined to capture surface and subsurface defects. For the surface level, YOLOv7 (a deep-learning object detector) was trained on RGB images to identify and classify visible defects, such as the quantity of enamel residue or several types of electrode footprints on the cable lug. For subsurface defects, a custom LSTM model was trained on time-series temperature profiles to detect anomalies (e.g., incomplete enamel stripping or abnormal crimping temperature) that are not visible at the surface. Secondly, the performance of both sensing techniques was examined in real time, highlighting the ability of IRT to uncover hidden defects while RGB imaging provides high-resolution surface data. The bimodal strategy leveraged advanced data acquisition in our in-house lab setup, ensuring that relevant defect features were captured for training the ML models. Validation experiments recorded up to a 60% reduction in validation loss for object detection, while classification tasks achieved an 80% decrease in error rates, resulting in a final accuracy of 92% in defect prediction for thermally crimped wires. Lastly, a framework consolidating these findings has been proposed for robust, non-destructive process monitoring in EM manufacturing. The inspection process becomes more comprehensive and efficient by merging the strengths of RGB and IR sensing and incorporating cutting-edge machine learning models. These promising results pave the way for further optimisation in EM manufacturing, reducing scrap rates, lowering production costs, and ultimately accelerating time-to-market for high-quality electric products.

Manufacture and use of soft magnetics materials for high performance applications within electrical machine and drive systems

Reece EBLET

University of Sheffield

Reece’s project is concerned with developing an understanding in several aspects of the design, material selection and manufacturing processes for achieving ultrahigh efficiency in MW rated electrical machines for aero-propulsion systems. Although performed largely within the context of MW machines, many of the findings should have sufficient generic value to smaller machines for e-taxi and smaller end of the regional aircraft sector. Recent work within this PhD involves concluding loss testing under temperature conditions, various design studies and trade-off analysis, investigation of rotational loss. The intention of these design studies and rotational loss investigation is to improve loss model accuracy and to assist in highlighting areas where design improvement may be possible.

Novel Rotor Design for Cost Optimised, High Temperature, High Speed Aerospace Applications

WEI LIANG ChOONG

University of Sheffield

The focal point of Choong’s PhD is on high-performance and lightweight electrical machine rotors, using a combination of advanced magnetic materials, hightemperature substrates, and high-modulus carbon-fibre composites. The finite element 3D structural modelling aspects of this project have been carried out on various design concepts, which were an evolution from a previously developed aerospace R&D electrical machine. The design concepts incorporated a hightemperature substrate in the containing structure, as well as a carbon-fibrereinforced polymer as the outer containment solution to accommodate highspeed operational conditions. The current design concept is under development, iterated from lessons learnt in previous design concepts, with innovative features to allow for a leaner design, such as the elimination of additional components to further improve power density. The anisotropic properties of carbon-fibre composites were taken into account during 3D mechanical finite element modelling in the structures of all of the design concepts. This was carried out by assigning representative coefficients of thermal expansion, orthotropic elasticities, Poisson’s ratios, shear moduli, orthotropic stress limits and so on, in the radial, circumferential (hoop) and axial directions. Static electromagnetic finite element modelling and design iterations were also performed to simulate the magnetic force components during manufacture. 60

Optimisation of coil winding

John McKay

Strathclyde University

John’s PhD involved taking advantage of the design and manufacturing freedoms afforded by the use of additive manufacturing of metals, specifically the Laser Bed Powder Fusion Process. Novel winding geometries were explored using an algorithmic data driven process, utilising a genetic algorithm and meta-models, coupled with a highly time efficient electromagnetic FEA based simulation model. The aim was to explore the design space and optimise a novel winding structure that could potentially outperform traditionally wound copper and aluminium windings. Over 25,000 FEA simulations were conducted and around 300,000 algorithmic iterations were performed resulting in 46 concentrated and distributed winding designs. It was found that the resulting novel winding structures were around 6-7% more performant when compared to a benchmark winding design, which represented a traditional wild wound winding configuration. It was also found that winding mass can potentially be optimised and reduced, resulting in less material usage, reduced cost, increased motor compactness and density. A Motorette sub-assembly model of one of the most performant additively manufactured winding designs was constructed from the additively manufactured winding parts. AC and DC tests were performed, and it was found that the RAC/RDC value deviated by only 9.4% compared to the high precision 3D electromagnetic model of the constructed winding. Extensive materials testing was conducted at the Advanced Forming Research Centre to establish how the additive manufacturing process affected sample part properties such as residual stress, density, porosity, grain structure and micro hardness. As part of the outputs of his PhD John has published two research papers in IEEE OpenAccess.

PhD graduates Dr Ji QI (2022)

Thesis Title: Electromagnetic Performance of Consequent Pole Permanent Magnet Machines, with Particular Reference to Analysis and Minimization of Torque Ripples.

Dr ze zhang (2023)

Thesis Title: Deep learning-based multi-sensor fusion for industrial process monitoring.

Dr Hao CHen (2024)

Thesis Title: Fibre Bragg Grating Sensor Based Electric Machine Condition Monitoring and Fault Detection Techniques.

Dr daniel harper-hill (2024)

Thesis Title: Metallic Rotor Containment Sleeves for Permanent Magnet Machines.

We have 5 PHD Students Submitting in 2025 - Reece EbLET - Wei Liang Choong - JOhn McKAY - Leigh Paterson - Ioan-ALexandru Herdea 62

Feasibility projects

Since the start of the FEMM Hub, We have funded 14 feasibility projects. An update on a selection of these can be found below

HiPPES – High Performing and Processible Electrical Steels Background With the growth in electrification there is a drive for improved performance of electric motors. Improvements in electrical steels, which are used for the rotor and stator in e-machines, includes production of thinner strip and steels with higher resistivity (both to reduce eddy current losses) as well as improved magnetic properties (to reduce iron losses). The majority of electrical steels are based on a Fe-3 wt% Si composition, which can be produced in bulk using hot/cold rolling and heat treatments. In recent years a Fe-6.5 wt% Si grade has been commercialised which has superior properties particularly for high-speed motors. However, this steel requires an expensive vapour deposition / heat treatment process to diffuse Si into the strip as the high Si content makes the material brittle and it cannot be cold rolled. Lab production of Fe-4.5 wt% Si steels have been reported in the literature, that can be processed using warm rolling give improved properties, although they are not yet commercialised. Therefore, there is a market pull for improved electrical steels and a need to consider alternate alloy compositions and or processing routes.

Figure 1: Frequency-magnetic loss plots for experimental alloy E2 compared to commercial grade M250-35A using B=1T.

Feasibility project The work carried out developed a proof-of-concept approach for designing a new family of electrical steels, with compositions that move away from being primarily Fe-Si based, with improved magnetic / electrical properties but still being processable using current commercial production routes. A design approach using fundamental scientific principles, thermodynamic and kinetic prediction tools was established, and a new composition space identified for high performance electrical steels using low cost alloying additions. This work allowed the WMG Rapid Alloy Production (RAP) facility, developed for structural steels, to be assessed for its use for electrical steels. To achieve this a benchmark Fe-3 wt% Si steel was produced, which was compared to a commercial grade and a Fe-6.5 wt% Si material. In addition, a new experimental composition electrical steel was produced. The RAP route produces electrical steels using vacuum induction melting and casting, followed by hot rolling, annealing, cold rolling, final annealing then mechanical and magnetic testing to commercial standards. Development in process was required to achieve the ultra thin product (0.2 – 0.35 mm) and final grain size control during annealing in samples large enough for full scale magnetic and mechanical testing. The mechanical and magnetic/electrical properties of the different steels were measured and compared. The properties were used within an electric motor model to compare the predicted torque and losses during operation at different frequencies. The outcome of the feasibility study was to confirm the viability of the electrical steel alloy design approach, RAP process for electrical steels and initial experimental verification trials demonstrating that improved properties can be achieved for a designed alloy. Follow on activities The work on high performance electrical steels continued after the feasibility project, supported in part via funding through a Royal Academy of Engineering Chair position, internal funding from the Advanced Steel Research Centre at WMG, an internship student from the University of Saclay and more recently a WMG funded PhD studentship. The design approach for high performance electrical steels has been further refined and further experimental trials carried out using the RAP line. Significant improvements, compared to commercial Fe-3 wt% Si based electrical steel, have been achieved in terms of resistivity, iron losses and tensile properties, whilst maintaining processability (i.e. ability to hot and cold roll). Figure 1 shows an example of the improved iron loss properties at high frequencies for one of the new alloys developed. Outputs The work has generated a patent [1], two conference attendances (one paper and one poster) [2, 3] and a journal paper [4]. 1. UK patent application GB2414302.6, Non-Grain Oriented Electrical Steel Alloys, The University of Warwick, filing date 30 September 2024 2. X. Ma, C. Slater, C. Davis and J. Soulard “Influence of Electrical Steel Grade on Different Types of Traction Motors” International Conference on Electrical Machines (ICEM2022) conference, Sept 2022, Spain 3. G. Lagorce, C. Slater and C. Davis, “Mapping the grain size, frequency and resistivity dependence on magnetic losses in high performing non grain orientated electrical steels” SteelSim 2023, Sept 11-13, Warwick, UK (poster) 4. C. Slater, X. Ma, G. Lagorce, J. Soulard and C. Davis, “Novel alloy designed electrical steel for improved performance in high frequency electric machines” submitted to JMMM (MAGMA-D-24-02566)

Aerosol deposition of ceramic coatings for high performance machine insulation The overall aim of the project is to demonstrate the feasibility of using particulate aerosol deposition (AD) to manufacture electrically insulating ceramic coatings on metallic conductor wires, including both bare copper and as a top-coat onto polymer-insulated copper wires. It is anticipated that such ceramic-insulated wires could be used to either: (i) significantly increase the permissible operating temperature of electrical machine insulation or (ii) significantly enhance the partial discharge endurance. The project will further develop previous deposition experiments carried out on flat polymeric insulation samples, which demonstrated that a thin (~ 5 µm) ceramic coating could be deposited onto a polyether ether ketone (PEEK) sheets at room temperature without inducing any structural or chemical modifications to the surface. It was subsequently found that the ceramic coated polymer insulation exhibited a a 70x increase in lifetime under a partial discharge endurance test in air. The work will examine the feasibility of placing these coatings onto round wire and hairpin samples. For the first phase of the project, a commercial alumina powder (CTS530SG Al2O3, Almatis GmbH) has been processed by high energy milling and spray drying to produce a fine granulated powder suitable for use in the AD process. The substrate holder in the AD process chamber was modified to include a rotating wire sample fixture, then an initial set of coatings was deposited directly onto copper wires with a circular cross-section. Although problems have been encountered in depositing uniform coatings along the length of the wire, due to alignment issues, our preliminary observations show the successful deposition of dense, nanocrystalline coatings with a thickness of approximately 4.5 µm. Furthermore, there was minimal deformation or oxidation at the ceramic-copper interface due to the use of fine particles with low abrasive character and the nature of the room temperature deposition technique. The next stages of this work will extend the deposition experiments to include wires having a rectangular cross-section and bi-layered ceramic-polymer insulation. Subsequently, the endurance of these ceramiccoated wires will be evaluated under partial discharge testing and benchmarked against conventional polymer-insulated samples.

(a) Optical photo of alumina coating on copper wire produced by aerosol deposition; scanning electron micrographs of (b) surface fragmentation induced by severe bending and (c) nanostructured ceramic coating layer with undamaged alumina-copper interface.

A critical evaluation of large-scale DD wind turbine electrical machines manufacturing techniques considering sustainability aspects and recyclability issues (‘CEDEMSARI’) In this project, the available structural designs were characterised considering machine’s total cost, manufacturing technique, functionality and sustainability of materials. Taking as an example the IEA 15MW NREL direct-drive wind turbine and by looking at Scotland’s supply chain, its structure was optimised under these parameters and compared with the actual proposed structure. The optimisation procedure was monitored with a view to learn about its advantages and disadvantages and to gather data that could be used in more ambitious optimisations. A selection of materials connected to a LCA, considering not only the variables stated above but also environmental impact, including CO2 emissions and water and electricity usage during material extraction and structure manufacturing stages, was carried out leading to a paper being published and presented in the IET PEMD 2023 international conference, https://ieeexplore.ieee.org/ abstract/document/10324823. This piece of research revealed that 11.1 million litres of water are currently used during the casting production processes of electrical generator rotor structures for such machines, which is equivalent to over four Olympic swimming pools of wastewater and eutrophicated water. Following an integrated approach and making use of the previously selected material, the team designed a lightweight optimised structure that was evaluated from static and dynamic viewpoints and that could be manufactured using traditional methods, such as casting. By considering typically underestimated loading conditions – thermal loads – and by analysing the effect of each load individually and together, it was possible to quantify their effect so the design could be modified accordingly. This demonstrated that loads’ effect varies as the size of the machine increases following a non-linear pattern. Through an iterative process in which the physical dimensions were changed and different features were introduced manually – structural stiffeners - the structure was modified and the effect of these modifications quantified. A significant amount of data were produced, stored and filtered so it could be used as input for structural generative design models based on AI and generate further optimised structural models that could be produced employing novel manufacturing methods, such as 3D printing (see below).

Manual structural optimisation showing impact of hole diameter on deformation for partial-depth cut-outs in the cylinder vs. AI model produced through generative design.

This work led to the publication of 2 journals papers, https://www.mdpi.com/2075-1702/11/8/780 and https://www.mdpi.com/2075-1702/12/4/277 and the acquisition of support for a fully funded PhD international scholarship, provided by Edinburgh Napier University, to continue with the investigation. New research streams were created because of this project with students in Edinburgh Napier University performing investigations in the field that were subsequently approved for publication. See https://www. mdpi.com/2674-032X/3/3/20 and https://www.mdpi.com/2071-1050/16/2/545. In addition, a fruitful collaboration with Siemens-Gamesa Renewable Energy was established and further project proposal discussions are still ongoing. A collaboration was established too with Stanford University and Prof. S. Tsai for the use of composite materials in generator supporting structures and new manufacturing methods that can be applied for their mass production. Consequently, Dr Pablo Sola was invited to lead a Special Issue in the Wind MDPI journal which is open for submission of papers on the field, https://www.mdpi.com/journal/ wind/special_issues/28EQ3AD8PF. 66

Robotic disassembly of electric motors Electric motors (EMs) consist of high-value components, such as copper and magnetic materials. The magnetic materials, often made from rare elements, are crucial strategic resources for the industry. The surge in electric vehicle (EV) adoption has significantly increased the importance of managing the End-ofLife (EOL) of EMs. As these components reach the end of their service life, remanufacturing emerges as a crucial solution. By returning EOL products to their original condition, remanufacturing extends product lifespans, conserves critical materials, and significantly reduces the environmental impact associated with manufacturing new components. Effective disassembly plays a pivotal role in the successful remanufacturing of EMs.

(a) Product view: permanent magnet DC motor

(b) Product View: AC induction motor

(d) Components in the AC induction motor

This project develops robotic disassembly technologies for electric motors. To evaluate the effectiveness of these technologies, the project compares robotic disassembly with manual processes using two representative EM types: a permanent magnet DC motor used in industrial fans (Figure 1(a)) and an industrial AC induction motor (Figure 1(b)). A Technology Readiness Level 4 (TRL) robotic cell prototype was designed and built at the University of Birmingham to disassemble both types of motors (Figure 2). This cell comprises two collaborative robots, a pin clamp device, and a press-fit component disassembly device (Figure 1 (c) and Figure 1 (d)). The two robots collaborate to perform key tasks, including: -

Unfastening: Removing fasteners such as screws and bolts. Coil Disassembly: Detaching and removing the motor windings. Magnetic Material Removal: Extracting permanent magnets.

The press-fit component disassembly device and the pin clamp device were designed to accommodate components of varying sizes and shapes, enhancing the cell’s versatility.

Figure 2: Robotic cell [1]

A video demonstrating the DC motor disassembly has been made publicly available: “Robotised disassembly of a DC motor”. The robotic disassembly process significantly outperforms manual methods, showing an up to 56.93% increase in speed. Our research highlights several key advantages of robotic disassembly: (a) Improved Copper Coil Disassembly: Robotic cutting ensures precise and controlled removal of coils, minimising damage to other components and reducing the risk of injury from flying debris. This contrasts with manual disassembly, where controlling the cutting tool can be challenging and increases the risk of accidents. (b) Enhanced Magnetic Material Removal: Robotic systems can safely and efficiently remove the magnetic rotor set (B) from the stator set (C.13), minimising the risk of magnet damage caused by the strong magnetic forces encountered during manual disassembly. (c) Faster Press-Fit Component Removal: The robotic cell utilises the pin clamp device and the pressfit component disassembly device to efficiently remove press-fitted components. This significantly reduces disassembly time compared to manual methods. Building upon these advantages, future work will involve testing the robotic cell with various types of EOL electric motors in an industrial environment. The ultimate goal is to advance the TRL to 8 or higher, paving the way for commercialisation. Reference 1. Liang, C. ,2025. Robotic Disassembly of a Permanent Magnet DC Motor. LF3 AUTOREMAN Lab, University of Birmingham.

Thermally Stable Electric Insulation Materials and Technologies via Wet Chemistry (ThermInsu) This feasibility study explores using inorganic-organic nanohybrids as the core material to develop ceramicceramic composite electrical insulations with the strategy to exploit the organic moiety for enhancing processing performance and the inorganic component for imparting high temperature stability. The project proceeds in two pathways: (i) the wet process through solution formulating and (ii) the dry process via powder coating technology. Significant progress has been achieved regarding coating formulations and manufacturing techniques.

Wet manufacturing process

This wet chemistry route formulates ceramic-based coating solutions and then applied on conductor wires through a reel-to-reel process. The coat on wire is converted to ceramic-ceramic composite insulation by heat treatment after forming into designed windings. Due to the targeting high temperatures (> 300°C), nickel-plated copper wires are commonly selected to retard conductor. However, nickel has poor adhesion to the ceramic-based coatings. To address this issue, we deposited a nickel-iron alloy coating on copper surface by electroplating process. A Taguchi experimental design was employed to evaluate the influence of bath composition and operating conditions like nickel-to-iron ratio, temperature, current density, and silica content, to achieve designed surface morphology, coating uniformity, and adhesion performance. Figure 1 demonstrates an example of a highquality electrical insulation coating capable of 450°C on the nickel-iron coated copper conductor. The outcomes achieved so far is to be presented at the Annual International Conference on Materials Science and Nanoscience (AICMSN2025), Rome, March 1315, 2025. Figure 1: The nickel-iron alloy coating deposited on copper (left) and the overcoated ceramic composite coating (right) after heat treatment at 450°C for 10 hours

Powder coating route

Additive manufacturing (3D printing) is applied to produce specially profiled electrical windings for enhanced magnetic flux and thermal dissipation. The rough product surface from additive manufacture places a big challenge for common insulation techniques because the insulation materials tend to flow into troughs on the surface, leaving apex area uncoated. This feasibility study exploits the non-flowable feature of ceramic materials to tackle such hurdle via formulating ceramic-based powder coatings. Ceramic-based powder coatings comprise ceramic binders as the matrix and dielectric-functionalised fillers as reinforcing agents are synthesised and delivered on aluminium substrate by electrostatic powder spraying. A series of powder coating formulations and operational parameters were optimised using Taguchi method. Figure 2 illustrates the ceramic coatings on aluminium substrates: both micrographs show excellent adhesion between the coating and substrates and the coatings have dielectric strength at about 5kV/mm. The left image confirms the coating remains intact after bending to 4 mm diameter, showing it has adequate flexibility and the right micrograph indicates the coating fill the rough conductor surface and forms a smooth coat. This work is also to be presented at AICMSN2025. 69

Figure 2 Ceramic powder coatings on 0.1mm aluminium sheet and bent at 4mm diameter (left) and on 3D printed aluminium coil (right) after heating at 450°C for 10 h

AM4EM: Novel Manufacturing-led Structures for Electrical Machines Under Extreme Working Environments Report Summary

Laser powder bed fusion (LPBF) is an innovative digital manufacturing technology in which intricate geometries can be manufactured layer-by-layer directly from the feedstock material. Due to the design freedom offered by the LPBF technique it is considered an attractive production method for the design of next-generation electric machines. In this study, we investigated the LPBF of two feedstocks, copper, copper with chemically modified graphene and Fe-Si details of which are reported below: Output 1.1 Copper: One of the main challenges in adopting LPBF for high-value engineering applications is the limited availability of commercial feedstock. This issue stems from the poor laser-matter coupling efficiency of transparent materials (e.g., glass) and highly reflective powders (e.g., copper and aluminium), which require high energy inputs to melt. To overcome this, we have developed chemically modified graphene (CMG) that enhances the printability of these materials through a photo-thermal effect. In our study, we examined the performance of CMG in improving the printability of pure copper using a custom LPBF machine QUAD-ISOPR. We tested 56 parameter combinations of power and velocities and used surface roughness, and defect process maps to find the optimum print conditions. We further performed in situ synchrotron imaging to characterise the melting modes, namely unstable keyhole, stable keyhole, vapour depression and conduction. We captured images of the evolving melt pool and spatter patterns at 40 kHz and quantified melt pool geometry, printing modes, and defects. The effectiveness of CMG is demonstrated in Figure 1(ab), where the welding of 8 layers of pre-printed pure Cu and rGO is shown. Pure Cu reflects the incident NIR laser (Figure 1a), while Cu-CMG exhibits a characteristic printing mode. The improved absorption due to the addition of CMG is further confirmed by measuring the meltpool intensity by high-speed optical imaging (Figure 1c) and direct absorptivity measurements from UV-Vis spectroscopy (Figure 1d). Output 1.2 Fe-6.5 wt% Si: Iron-silicon (Fe-Si) alloys are soft magnetic materials primarily composed of iron, with silicon concentrations ranging from 0.5% to 6.5% by weight. Traditionally, the manufacture of laminated Fe-Si structures used in electric machines involves multiple processes such as cutting, punching, and welding. However, these can be replaced by digital manufacturing techniques like Laser Powder Bed Fusion (LPBF). The non-equilibrium solidification conditions of LPBF can promote favourable microstructures and textures, leading to low core loss and good magnetic performance in electric machines. In this study, we investigated 70

the influence of process parameters, specifically power and velocity, on printability, surface roughness, and microstructure properties. We developed process maps for single (Figure 2(a)) and multiple layer single track builds and identified optimum operating conditions. Additionally, using X-ray radiography, we examined the parameters that induce cracking in the printed track for multilayer samples (Figure 2(b)). The study is ongoing, and we are currently characterising microstructures and exploring methods to improve powder spreading.

Figure 1: Radiographs showing the laser track interaction during the welding of (A) Pure copper and (B) Cu-rGO at 400W, 500 mm/s. (C) Average gray scale intensity captured by the inline Photon camera during the welding of two powders (D) Diffuse reflectance response by UV-Vis spectroscopy for the powders, with Cu-rGO showing nearly 3 times better absorption in the NIR laser range.

Figure 2: (a) Process map of single layer singe tracks (b) Radiographs of select multi-layer prints with cracking in top layers.

Output 2.1 2-D and 3-D Electromagnetic Analysis of DSSRM: Double-Stator Switched Reluctance Motors (DSSRMs) are magnet-free, robust designs that are gaining attention as an alternative to Permanent Magnet Synchronous Motors (PMSMs) due to their sustainability, cost-effectiveness, and high efficiency. General design parameters and material selection for the initial model are reported in Table 2. Despite these advantages, DSSRMs face performance limitations in high-demand applications, such as lower copper filling factor (CFF) and reduced torque and power density. To address these limitations, this research proposes a novel high-fidelity modelling approach combined with additive manufacturing (AM) techniques to enhance winding design. Table 2: General parameters and specifications of a 50kW DSSRM (benchmark) for initial study.

Phase number Stators slot/ rotor pole Ns/Nr Stator outer diameter Stator inner diameter Coil number per phase Air-gap length Stator and rotor cores Stator coils Motor shaft Motor water cooling jackets, frame, end caps and other structures

3 12:10 290mm 95mm 4 0.75mm M5 electric steel Copper Stainless Stell Aluminium

The primary objective is to increase the CFF, leading to improvements in torque, power density, and overall efficiency. Comparative analysis of motor performance before and after winding optimisation is conducted. The research employs a 3D FEM for comprehensive electromagnetic and thermal analyses of the high-fidelity model, providing a more accurate representation of motor performance and temperature rise under realworld conditions. By integrating AM with high-fidelity modelling and analysis, this study demonstrates that DSSRMs can achieve performance levels competitive with PMSM. These methodologies reveal new research pathways for advanced motor designs, potentially reducing reliance on rare-earth materials and offering sustainable, cost-effective solutions for various industrial applications. The motor’s high-fidelity model with optimal winding structure is shown in Figure 3.

(a)

(b)

Figure 3: High-fidelity model of DSSRM with (a) optimised-AM windings used in outer and inner stator cores, (b) cross-section view. 72

The simulation results demonstrate that the optimal winding design increased the CFF of the outer and inner stators from 50% (using conventional copper coils) to 70.8% and 65.9%, respectively. The motor’s output torque improved by 23.7%, while its power density increased by 10.5%. Figure 4 presents the optimisation result of the model using a genetic algorithm where the goal is torque maximisation and torque ripple reduction. A detailed performance comparison is shown in Table 2. The high-fidelity model shows low output torque, uneven magnetic flux distribution, increased harmonic, reduced efficiency, and shifts in high-efficiency regions. These discrepancies are primarily due to the high-fidelity model’s end windings, end effects, and non-uniform magnetic field distribution along the motor’s axial length. As CFF and winding usage increase, the motor will inevitably bring more Joule losses. In the DSSRM design, both the outer and inner stators are equipped with cooling jackets for effective temperature management. Beyond the electromagnetic analysis, future research will continue assessing thermal performance to confirm the feasibility of the optimal design, particularly in managing the increased Joule losses. Thermal simulation results will be addressed in subsequent research and included in the study.

Figure 4: Model structure optimisation result in genetic algorithm.

Table 3: Performance comparison between benchmark and optimised motors

Parameter Average Torque (Nm) Torque Ripple Efficiency Torque density (Nm/kg) Power Density (kW/kg)

Benchmark 259.0 60.2% 88.0% 7.76 1.62

Optimised 357.9 63.1% 91.4% 8.53 1.79

Additive Manufacturing of Stator Winding for Cryogenically Cooled Axial Flux Motors Project Overview

This feasibility study explores the application of additive manufacturing (AM) for stator windings in cryogenically cooled axial flux motors. The goal is to enhance efficiency and enable greater design flexibility for electric motors in aircraft propulsion systems.

Objectives

1. Investigation of Additive Manufacturing Techniques - Explore and assess the feasibility of using AM for stator windings in axial flux motors. 2. Electrical Characterization - Measure and analyse the electrical properties of AM stator windings at room and cryogenic temperatures. 3. Magnetic Characterization - Evaluate the magnetic properties of soft magnetic composite cores using stators with small air gaps, energized by the AM stator windings, at both room and cryogenic temperatures.

Key Outcomes Electrical Performance -Additive manufacturing copper achieves 95.6% International Annealed Copper Standard (IACS) conductivity after heat treatment. -Electrical conductivity improves by a factor of 7-9 in liquid nitrogen compared to room temperature. -Significant reduction in DC resistance when cooled to cryogenic temperatures. Performance Potential - Cryogenic operation demonstrates potential for high power density and improved efficiency due to enhanced current loading.

Loss Reduction - At motor frequency of 150 Hz, losses for axial flux motor using additive manufacturing stator winding in liquid nitrogen are reduced by 60% compared to room temperature. - Losses for axial flux motor using additive manufacturing stator winding remain lower than room temperature levels at frequencies up to 500 Hz. Manufacturing Innovation - Additive manufacturing introduces a versatile toolset, broadening the spope for innovation in electric motor manufacturing, including new materials, design topologies and roduction methods.

Impact Summary • •

Research findings were presented at the Applied Superconductivity Conference (ASC) in September 2024, highlighting advancements in additive manufacturing technology for cryogenic motor applications. This work underscores the transformative potential of integrating additive manufacturing in electric motor development for aerospace applications, contributing to future innovations in propulsion technologies.

Progress Report

Copper Additive Manufacturing Sample Testing

Copper strip as-built

Copper strip heat-treated 74

Electrical Performance - Additive manufacturing copper achieves 95.6% International Annealed Copper Standard (IACS) conductivity after heat treatment. - Electrical conductivity improves by a factor of 7-9 in liquid nitrogen compared to room temperature. - Significant reduction in DC resistance when cooled to cryogenic temperatures. Cryogenically Cooled Axial Flux Motor

Axial flux motor stator

Experimental testing

PUBLICATIONS THe FUture electrical machines manufacturing hub, funded by EPSRC, has made significant contributions to advancing the knowledge and development of electrical machine technologies. The publications arising from the FEMM Hub reflect the collaboration efforts between academia and industry. This section of the report presents a list of peer-reviewed open access papers showcasing the outcomes of the hub’s research activities and their impact on the future of electrical machine manufacturing.

Prajapat, N., Turner, C., Tiwari, A., Tiwari D. et al. Real-time discrete event simulation: a framework for an intelligent expert system approach utilising decision trees. The International Journal of Advanced Manufacturing Technology, 110, 2893– 2911 (2020). https://doi.org/10.1007/s00170020-06048-5

2019 Oyekan, J., Fischer, A., Hutabarat, W., Turner, C. and Tiwari, A. (2019). Utilising low cost RGB-D cameras to track the real time progress of a manual assembly sequence. Assembly Automation, Emerald, ISSN: 0144-5154, vol. 40, no. 6, 925-939.

Tiwari D, Farnsworth M, Zhang Z, Jewell GW, Tiwari A. In-process monitoring in electrical machine manufacturing: A review of state of the art and future directions. Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture. May 2021. doi:10.1177/09544054211016675

2020 Okorie, O., Charnley, F., Ehiagwina, A. , Tiwari, D., Salonitis,K. Towards a simulation-based understanding of smart remanufacturing operations: a comparative analysis. Jnl Remanufactur (2020). https://doi.org/10.1007/ s13243-020-00086-8

Oyekan J, Farnsworth M, Hutabarat W, Miller D, Tiwari A. Applying a 6 DoF Robotic Arm and Digital Twin to Automate Fan-Blade Reconditioning for Aerospace Maintenance, Repair, and Overhaul. Sensors. 2020; 20(16):4637. https://doi. org/10.3390/s20164637

S. Khan, M. Farnsworth, R. McWilliam, J. Erkoyuncu. (2020). On the requirements of digital twin-driven autonomous maintenance. Annual Reviews In Control. 50, 13-28. https://doi. org/10.1016/j.arcontrol.2020.08.003

Prajapat, N., Turner, C., Tiwari, A. et al. Realtime discrete event simulation: a framework for an intelligent expert system approach utilising decision trees. Int J Adv Manuf Technol 110, 2893–2911 (2020). https://doi.org/10.1007/ s00170-020-06048-5

Oyekan, J., Hutabarat, W., Turner, C., Arnoult, C. and Tiwari, A. (2020). Using Therbligs to embed intelligence in workpieces for digital assistive assembly. Journal of Ambient Intelligence and Humanized Computing, Springer, vol. 11, 2489– 2503, ISSN: 1868-5137

Asymmetric Pole Shaping Method," in IEEE Transactions on Industry Applications, vol. 58, no. 3, pp. 3545-3557, May-June 2022, doi: 10.1109/ TIA.2022.3159629.

2021 Tiwari, D.; Miscandlon, J.; Tiwari, A.; Jewell, G.W. A Review of Circular Economy Research for Electric Motors and the Role of Industry 4.0 Technologies. Sustainability 2021, 13, 9668. https://doi.org/10.3390/su13179668

D. Miller, B. Song, M. Farnsworth, D.Tiwari, F. Freeman, I. Todd, A. Tiwari, 'IoT and Machine learning for in-situ process control using Laser Based Additive Manufacturing (LBAM) case study', Procedia CIRP,Volume 104, 2021, Pages 18131818, ISSN 2212-8271, https://doi.org/10.1016/j. procir.2021.11.306.

Izhar Oswaldo Escudero-Ornelas, Divya Tiwari, Michael Farnsworth, Ashutosh Tiwari, 'Modelling Interdependencies in an Electrical Motor Manufacturing Process Involving Deformable Material', Advances in Manufacturing Technology XXXIV, Vol.15, pp. 291 - 298. DOI: 10.3233/ ATDE210051

J. Oyekan, Y. Chen, C. Turner, A. Tiwari,, ‘Applying a fusion of wearable sensors and a cognitive inspired architecture to real-time ergonomics analysis of manual assembly tasks’, Journal of Manufacturing Systems, Volume 61, 2021, Pages 391-405, ISSN 0278-6125, https://doi. org/10.1016/j.jmsy.2021.09.015.

"R. Wrobel, R.J. MGlen, 'Heat pipes in thermal management of electrical machines – A review', Thermal Science and Engineering Progress, Volume 26, 2021, 101053,ISSN 2451-9049,DOI: 10.1016/j.tsep.2021.101053."

M. Zhou, Z. Li, H. Assadi, I. Chang, C. Barbatti,’An accelerated three-dimensional coupled electromagnetic-mechanical model for electromagnetic pulse forming’, Journal of Manufacturing Processes, Volume 72, 2021,Pages 240-251,ISSN 1526-6125,https://doi. org/10.1016/j.jmapro.2021.10.007.

J. Oyekan, Y. Chen, C. Turner, A. Tiwari, 'Applying a fusion of wearable sensors and a cognitive inspired architecture to real-time ergonomics analysis of manual assembly tasks',Journal of Manufacturing Systems, Volume 61, 2021, Pages 391-405,ISSN 0278-6125,https://doi. org/10.1016/j.jmsy.2021.09.015.

2022

Farnsworth, M., Tiwari, D., Zhang, Z. et al. Augmented classification for electrical coil winding defects. Int J Adv Manuf Technol 119, 6949–6965 (2022). https://doi.org/10.1007/ s00170-022-08671-w

Clift L, Tiwari D, Scraggs C, Hutabarat W, Tinkler L, Aitken JM, Tiwari A. Implementation of a Flexible and Lightweight Depth-Based Visual Servoing Solution for Feature Detection and Tracing of Large, Spatially-Varying Manufacturing Workpieces. Robotics. 2022; 11(1):25. https://doi. org/10.3390/robotics11010025

"R. Wrobel, 'Thermal Science and Engineering Progress, A technology overview of thermal management of integrated motor drives Electrical Machines', Thermal Science and Engineering Progress, Volume 29, 2022, 101222, ISSN 2451-9049, https://doi.org/10.1016/j. tsep.2022.101222.

Igiri Onaji, Divya Tiwari, Payam Soulatianto rk, Boyang Song & Ashutosh Tiwari (2022) Digital twin in manufacturing: conceptual framework and case studies, International Journal of Computer Integrated Manufacturing, DOI: 10.1080/0951192X.2022.2027014

J. Qi et al., "Effect of Pole Shaping on Torque Characteristics of Consequent Pole PM Machines," in IEEE Transactions on Industry Applications, doi: 10.1109/TIA.2022.3156904. J Qi, ZQ Zhu, L Yan, GW Jewell, C Gan, Y Ren, S Brockway, C Hilton, "Suppression of Torque Ripple for Consequent Pole PM Machine by

F. Wei, Z. Q. Zhu, X. Sun, L. Yan and J. Qi, "Investigation of Asymmetric Consequent-Pole Hybrid Excited Flux Reversal Machines," in IEEE 77

Transactions on Industry Applications, vol. 58, no. 3, pp. 3434-3446, May-June 2022, doi: 10.1109/ TIA.2022.3151316.

Reaction on Electromagnetic Performance and Pole Shaping Effect in Consequent Pole Pm Machines’, Energies, 2023, 16, 1982.https://www. mdpi.com/1996-1073/16/4/1982

Ward, Michael James and Miscandlon, Jill and Salamati, Mohammad and Butler, David and Uflewska, Olga and Fehring, Feline, A Wicked and Complex Problem Framework Applied to Engineering Research Effectiveness in Resource Efficiency and Decarbonisation. Available at SSRN: https://ssrn.com/abstract=4151603 or http:// dx.doi.org/10.2139/ssrn.4151603

J. Qi, Z.Q Zhu, L. Yan, G.W. Jewell, C.Gan, Y.Ren, S.Brockway, C.Hilton, "Influence of Slot/Pole Number Combinations and Pole Shaping on Electromagnetic Performance of Permanent Magnet Machines with Unbalanced North and South Poles", IET Electric Power Applications, I1– 28 (2023). https://doi.org/10.1049/elp2.12293

Jill Miscandlon, Abbas Kazemi-Amiri, Stephen J. Forrest, Xiao Chen, Daniel Harper, Alasdair McDonald, Geraint W. Jewell, "A manufacturing driven design methodology to lightweighting of the structural elements of a permanent magnet electrical machine rotor," in IEEE Access, 2022, doi: 10.1109/ACCESS.2022.3214305.

Tiwari, D.; Miller, D.; Farnsworth, M.; Lambourne, A.; Jewell, G.W.; Tiwari, A. Inspection of Enamel Removal Using Infrared Thermal Imaging and Machine Learning Techniques. Sensors 2023, 23, 3977. https://doi.org/10.3390/s23083977 Goodall A.D, Chechik L., Mitchell R.L., Jewell G.W.,Todd I., ‘Cracking of soft magnetic FeSi to reduce eddy current losses in stator cores’, Additive Manufacturing, Volume 70, 2023, 103555 https://www.sciencedirect.com/science/article/ pii/S2214860423001689

Ze Zhang , Michael Farnsworth , Boyang Song , Divya Tiwari , and Ashutosh Tiwari, 'Deep Transfer Learning With Self-Attention for Industry Sensor Fusion Tasks', IEEE SENSORS JOURNAL, VOL. 22, NO. 15, 1 AUGUST 2022 Zhu, Z.Q.; Liang, D. Perspective of Thermal Analysis and Management for Permanent Magnet Machines, with Particular Reference to Hotspot Temperatures. Energies 2022, 15, 8189. https:// doi.org/10.3390/en15218189

Goodall A.D., Yiannakou G., Chechik L., Mitchell R.L., Jewell G.W, Todd I.,’Geometrical control of eddy currents in additively manufactured Fe-Si’, Materials & Design, 2023,112002, doi: 10.1016/j. matdes.2023.112002. https://www.sciencedirect. com/science/article/pii/S0264127523004173

J. Qi, Z.Q. Zhu, L. Yan, G.W. Jewell, C.W. Gan, Y. Ren, S. Brockway, and C. Hilton, “Analytical Analysis of Cogging Torque in Permanent Magnet Machines With Unequal North and South Poles, with Particular Reference to Consequent Pole Machines,” in IEEE Transactions on Energy Conversion, 2022, doi: 10.1109/TEC.2022.3221917.

X. Chen, H. Wu, J.D. Ede, G.W. Jewell, L.M. Jones, H. Ghadbeigi, A model to account for magnetic permeability changes resulting from edge damage caused by laser cutting in a high performance cobalt-iron alloy, Journal of Magnetism and Magnetic Materials (2023), doi: https://doi. org/10.1016/j.jmmm.2023.171081

2023

2024

N. Simpson, G. Yiannakou, H. Felton, J. Robinson, A. Arjunan and P. H. Mellor, "Direct Thermal Management of Windings Enabled by Additive Manufacturing," in IEEE Transactions on Industry Applications, vol. 59, no. 2, pp. 1319-1327, MarchApril 2023, doi: 10.1109/TIA.2022.3209171.

“Izhar Oswaldo Escudero-Ornelas, Divya Tiwari, Michael Farnsworth & Ashutosh Tiwari (2024) Modelling interdependencies in an electric motor manufacturing process using discrete event simulation, Journal of Simulation, 18:4, 604-625, DOI: 10.1080/17477778.2023.2202338

Qi, J., Zhu, Z., Yan, L., Jewell, G.W., Gan, C., Ren, Y., Brockway, S., Hilton, C., ‘Influence of Armature

R. Wrobel,'Analysis of power loss in heat pipes for integrated thermal management of next 78

generation electrical machines', Thermal Science and Engineering Progress, Volume 47,2024, 102358, doi: 10.1016/j.tsep.2023.102358.

publication). Digital Object Identifier: 10.1109/ ACCESS.2025.3539455 https://ieeexplore.ieee.org/ document/10876126/authors#authors

Fehring F, Ward M, Butler D. (2023). A wicked and complex problem analysis framework for electrical machine supply chain sustainability.

J. McKay, D. J. Miscandlon and D. T. Konkova, "Power Loss Observations in Algorithmically Designed PMSM Stator Windings utilizing the freedoms afforded by Additive Manufacturing.," in IEEE Access, doi: 10.1109/ACCESS.2025.3538813.

Paterson, L.; Miscandlon, J.; Butler, D. The Juxtaposition of Our Future Electrification Solutions: A View into the Unsustainable Life Cycle of the Permanent Magnet Electrical Machine. Sustainability 2024, 16, 2681. https://doi. org/10.3390/su16072681

2025 A.Mehrad Kazemi Amiri, K.Tartt, A.McDonald, Identifying path ahead for tackling future challenges in direct-drive permanent magnet wind turbine generator’s electro-mechanical design and manufacturing https://doi.org/10.1007/s10010025-00792-4

L.M. Jones, A. Winter, L. Tinkler, G.W. Jewell, H. Ghadbeigi, 'Influence of Remote Laser Cutting on Magnetic Loss and Mechanical Properties in 0.2 mm Silicon Steel', Journal of Magnetism and Magnetic Materials, Volume 607, 1 October 2024, 172400

If you would like a copy of any of our publications, please visit our website.

Z. Zhang, Y. Yao, W. Hutabarat, M. Farnsworth, Divya Tiwari and A. Tiwari, "Time Series Anomaly Detection in Vehicle Sensors Using SelfAttention Mechanisms," in IEEE Transactions on Intelligent Transportation Systems, doi:10.1109/ TITS.2024.3415435. David A Hewitt, Shubham Sundeep, Antonio Griffo, Jiabin Wang; 'Impact of close proximity pulse width modulation switching events on electric machine terminal voltages, IET Electric power applications, https://ietresearch.onlinelibrary. wiley.com/doi/10.1049/elp2.12495 Helen Elkington, Ben Mason, Mitchell Leering, Xiao Chen, Alexei Winter, Lloyd Tinkler, Kursad Sezer, Sundar Marimuthu,'Water jet guided laser cutting of electrical steel laminations’, Procedia CIRP, Volume 124, 2024, Pages 505-508. J. McKay, J. Miscandlon and T. Konkova, "The Design and Optimization of Additively Manufactured Windings Utilizing Data Driven Algorithms for Minimal Loss in Electric Machines," in IEEE Access, vol. 12, pp. 187406-187426, 2024, doi: 10.1109/ACCESS.2024.3509689. I. Herdea, D. Tiwari, A. Tiwari, "Data augmentation framework for improved classification in object detectors" in IEEE Access (Accepted for 79

b u H H C A E R OUT

VIsit our news page to keep up-to-date through out the year www.electricalmachineshub. ac.uk/news

Deputy Director Gives Evidence In House Of Commons FEMM Hub Deputy Director and University of Sheffield’s Deputy Vice-President for Innovation Professor Ash Tiwari was invited by the Science, Innovation and Technology Committee in the House of Commons to give evidence at its inquiry into innovation, growth and the regions. It was a great opportunity to share the University of Sheffield’s experiences with the success of our founder-focused Commercialisation Journey and discuss the critical role of universities and the UK’s innovation ecosystem in achieving the Government’s mission on economic growth. Universities play a fundamental role in driving innovation and fostering economic growth in regions across the UK and the Committee’s inquiry into ‘Innovation, Growth and the Regions’ inquiry is helping inform future Government policy.

Knowledge Exchange Visit in Brazil Valdis Krumins, Senior Project Engineer (Design) at the Design and Prototyping group of the University of Sheffield Advanced Manufacturing Research Centre (AMRC), has been working with the FEMM Hub team and had the privilege of participating in a knowledge exchange visit at the SENAI Institute of Innovation in Manufacturing and Laser Systems in Joinville, Brazil in October 2024. SENAI is the largest research centre network in Latin America, like TWI and the Catapult centres in the UK. 80

FEMM Hub Kicks Off 2025 With STEM Event! On the 14th of January, a team of FEMM researchers from AMRC travelled to Whiston Junior and Infants School in Rotherham to deliver an engineering workshop to 80 pupils. The team, led by Dr Lloyd Tinkler guided pupils through instructions resulting in teams working together to make a simple DC motor.

FEMM Hub visits Lund University, Sweden Glynn Atkinson visited Avo Reinap (FEMM hub scientific adviser) at the Industrial Electrical Engineering and Automation department, in Lund University, southern Sweden. Here he met undergraduate students and PDRA Leonardo Columbo who has developed a test rig for the evaluation and characterization of iron losses in electrical machine stators. The system is based around Labview and a linear amplifier and provides closed loop BH analysis of stator cores. Sinusoidal magnetisation was demonstrated at 1.8T and 5kHz.

2024 FEMM Hub Conference a Success! On Wednesday the 20th of November the FEMM Hub brought together over 100 leading experts and innovators in the field of electrical machines at the IET Austin Court for their annual conference. FEMM Hub Director Professor Geraint Jewell opened the conference by sharing his technical highlights of the past year before introducing our 2024 Keynote Speaker Professor John Erkoyuncu from Cranfield University. Professor Erkoyuncu presented “Digital Twinning: a through-life engineering perspective on emerging use cases, challenges and future directions” to a packed audience. The conference then proceeded through three different sessions - electrical machine manufacture, sustainable manufacture of electrical machines and emerging technologies. In addition to these sessions. we were joined by Dr Hadi Moztarzadeh, Head of Technology Trends at the Advanced Propulsion Centre who presented “E-motors value chains and manufacturing cost model: enabling a resilient supply chain and cross-sector collaboration”. All presentations were recorded and can be found on the FEMM Hub Website - https://www.electricalmachineshub.ac.uk/ The conference was an overwhelming success, with engaging presentations, insightful discussions, and active participation from attendees. It fostered valuable connections and inspired new ideas, leaving everyone eager for the 2025 conference . taking place on the 10th of December in Sheffield - we look forward to welcoming you then! To register your interest in attending the FEMM Hub Conference on the 10th of December, please get in touch with our Hub Administrator, Lindsey via email l.j.farnsworth@sheffield.ac.uk.

Dr ANNA ErMakova interviewed for International WOMEN’s DAY Dr. Anna Ermakova, Research Associate in Additive Manufacturing of Electrical Machines and FEMM Hub member from the University of Bristol, has been interview by Alexandra da Fonte Martins of CWIEME Talks for International Women’s Day. During her interview, Anna shares how additive manufacturing is revolutionising electrical machines for a net zero future. She discussed why she chose a career in engineering, her life changing experiences whilst studying in China where she was exposed to a lot of manufacturing methods and in time discovered lots of flaws in the methods of additive manufacturers. Anna explained how addictive manufacturing relates to electrical machines, some of the advancements and how they impact industry playing a major role in energy transition. She also explains the challenges the team face and their current developments. This session highlights innovation, advice for considering a career and the importance of women in engineering. The full interview in two parts can be viewed here. Part 1: https://www.linkedin.com/feed/update/urn:li:activity:7304109292926758912/ Part 2: https://www.linkedin.com/feed/update/urn:li:activity:7305888384298700801/

Conferences

Electric Drive Production Conference, Germany Dr Alexei Winter, AMRC, attended the Electric Drive Production Conference (EDPC) in Regensburg, Germany in December 2024. He delivered a paper on hollow conductor coils, research started by Dr Steve Forrest at the University of Sheffield. His presentation garnered a lot of interest from the delegates, several of whom stayed behind to talk further. Dr Winter networked with researchers in European institutes such as TU Aachen, FAPS at the University of Erlangen-Nuremberg and the Karlsruhe Institute of Technology and is pursuing potential collaborative projects with several of these.

FEMM Hub Present at IESSS, GERMANY On the 24th and 25th of April 2024, Dr Luke Jones from the University of Sheffield travelled to the International Electrical Steel Sheet Summitt (IESSS) in Aachen, Germany. His presentation titled “Effect of Increased Strain Rate by High-Speed Blanking of NonGrain-Oriented Silicon Steel” was well received. 84

FEMM Hub Exhibit at PEMD 2024, Nottingham The FEMM Hub team travelled to Nottingham from the 10 to the 13th of June 2024 to exhibit at the 13th Power Electronics, Machines and Drives International Conference (PEMD 2024). The PEMD conference series brings together specialists across the sector to share learning and identify collaboration opportunities. The event is renowned for bringing together industry and academia, to turn research into tangible products. During the 3 day conference, the FEMM Hub team members shared reports, papers and other research outputs with PEMD delegates at the exhibition as well as enjoying a number of different presentations during the conference sessions.

FEMM Hub Exhibit at FPC 2025 The FEMM Hub, alongside the AMRC, exhibited at the Future Propulsion Conference at the National Motorcycle Museum, Solihull on the 12th and 13th of March 2025. The FPC is an annual two day UK event created to bring together industry and academic experts within the propulsion development field. FEMM Hub GC2.3 lead Dr Lloyd Tinkler also delivered a presentation during the Electrical Machines session titled “High-speed Rotor Development and Testing”. More information about the conference can be found by visiting here: https://fpc-event. co.uk/

IEEE Conference on Electrical Systems for Aircraft, Ship propulsion and Road vehicles, Naples FEMM Hub’s PhD student Prithvi Bhagat published a paper at the IEEE conference on Electrical Systems for Aircraft, Ship propulsion and Road vehicles (ESARS) held in Naples from the 26th - 29th November 2024. The paper titled “A Methodology to Assess the Sustainability of E-motors in Electric Vehicles” summarises the growing electric vehicle demand in the past decade which has spiked rumor’s on sustainability of electric motors. It depicts a comprehensive approach to sustainable manufacturing of electric motors (specifically in-wheel electric motors) and produces a ranking system which allows motor components to be ranked based on different criteria’s (size, weight, material, cost etc.) It also includes a scope of improvement and an effort - impact score which is determined based on available opportunities in sustainable electric motor design.

Coiltech italia 2024 Dr Nick Simpson and Dr Anna Ermakova presented at this year’s Coiltech Conference in Pordenone, Italy in September. Tehir presentation was titled: Next-generation Additively Manufactured Electrical Coils. Abstract: The drive for Carbon Net Zero is increasing the demand for more powerful and efficient electrical machines in transport electrification. Metal Additive Manufacturing (AM) offers unmatched design flexibility for advanced electromagnetic coils. These coils feature innovative AC loss mitigation through spatially optimised conductor shapes, integrated thermal management such as liquid cooling channels, and new high-temperature insulation coatings. This presentation will showcase the latest advancements in AM for electrical machines, covering digital design techniques and the complex post-processing needed for low surface roughness and reliable electrical insulation.

Sustainability conference at alvier machatronics, sweden Glynn Atkinson Visited Alvier Mechatronics (a Hoganas company) for their Sustainability conference in Helsingborg, Southern Sweden on 21st May. In the morning Alvier showcased their developments in electrical machines for automotive applications using laminated steel and Soft Magnetic Composites, plus developments in electromagnetic, thermal and fluid particle simulations applied to automotive applications. The sustainability conference in the afternoon included presentations from Volvo Trucks, Lund University, Alvier, Hoganas, Additive Drives and McKinsey and Company. The common theme was the need to understand the full lifecycle cost of a product, its materials and lifetime energy use, and design this into the system during the development phase.

ICEM 2024, ITALY Dr Nick Simpson and Dr Anna Ermakova presented at this year’s ICEM conference in Turin. Their paper was titled: Toward an Accessible Electrical Conductivity Characterisation Method for Additively Manufactured Conductors. Abstract—The use of metal Additive Manufacturing to form electrical winding and busbar components is gaining popularity as both a prototyping and a production tool due to the ability to realise complex geometry, unparalleled by other production methods, and advantages in digital rather than physical tooling. However, the many different manufacturing processes and feed-stock materials available, the number of parameters attributed to each process, and differences among Additive Manufacturing practitioners leads to significant variation in the resulting elec-trical material properties of fabricated components. Such data is critical at the design stage and throughout production for quality control. This paper presents a standardised serpentine sample geometry, test fixture, and measurement procedure to reliably determine the electrical conductivity and temperature coefficient of resistivity. The procedure is based on an existing standard while the sample geometry, test fixture and suggested apparatus are designed to be simple and accessible to encourage adoption across disciplines along the Additive Manufacturing production chain and end-application. 87

Quarterly Research Meetings

Bristol June 2024

On the 5th of June, the FEMM Hub team gathered in Bristol for the Quarterly Research Meeting in the grand Wills Memorial Building. Kicking off the 2-day meeting, FEMM Hub Director Geraint Jewell welcomed the team to Bristol for the first time before we had our first presentation of the day from Newcastle’s Dr Glynn Atkinson, Luke Sanders and Yusuf Ugurluoglu. Following the update from Newcastle, the team heard updates from our Grand Challenge 2 projects: Manufacturing high-performance coils and ultimate control (presented by Dr Dave Hewitt); Additive manufacturing of high-performance electrical machine windings (presented by Dr Nick Simpson) and manufacturing technologies for flexibility and customisation (presented by Dr Alexei Winter). We began day 2 with a tour of the University of Bristol’s facilities in the Queen’s Building led by Dr Nick Simpson. Following the tour, we moved back to the Wills Memorial Building to continue with the presentations starting with the cross-cutting themes: In-process tracking and tractability for zero-defect manufacture of electrical machines (presented by Dr Michael Farnsworth) and the Demonstrator (presented by Dr Glynn Atkinson). Following lunch, we finished our day with presentations from our aligned projects: Cut edge characterisation in advanced electrical alloy (presented by Dr Luke Jones) and From Nominal core properties to in-service performance (presented by Dr Xiao Chen).

Glasgow SEPT 2024 On the 11th and 12th of September 2024, the FEMM Hub Team gathered in Glasgow for their Quarterly Reseach Meeting. Our Hub Director Professor Geraint Jewell opened the first day of the QRM with an update on overall hub progress as well as discussing our upcoming conference (for information on this free event please click here). Before we moved on to presentations from our team in Newcastle, NMIS and the University of Sheffield. Following lunch, the team undertook EDI training looking at Inclusive Language. We began day 2 of the FEMM Hub QRM with a tour of the Power Networks Demonstration Centre. The PNDC was founded by the University of Strathclyde, Scottish Power Energy Networks and SSE Power Distribution, with support from Scottish Enterprise and the Scottish Funding Council. It is a world-class research, development and demonstration venture and plays a key role in accelerating emerging technologies towards commercial deployment in a realistic, controllable environment. This is done through the use of a fully operational HV and LV demonstration network (operated either as a grid connected or as an islanded system), integrated with state-of-the-art communications and monitoring equipment, as well as other bespoke integrated functionality. Following our return to the University of Strathclyde we continued with our research presentations before closing with lunch at 2pm.

Sheffield FEbruary 2025 On the 12th and 13th of February 2025, the University of Sheffield hosted a successful FEMM Hub quarterly research meeting, attended by over 20 of its team. The day opened with Hub director, Professor Geraint Jewell giving an overview of recent activities and publications as well as welcoming our two new members Memet and Rahul. Throughout the two-day meeting, we heard detailed updates from each of our projects as well as undertaking a short training session on public engagement.

MOnthly project meetings

Since 2020, each of our FEMM Hub project teams meet monthly. During these online hour long meetings, researchers give presentations detailing that months progress before spending time discussing next steps and gaining valuable advice from others on the call. These meetings are open to any member of staff belonging to our hub partners. There is no obligaton to attend these regularly, we welcome any opportunity to share our research progress.

If you would like to find out more about joining our meetings, please contact FEMM Hub Administrator Lindsey Farnsworth - L.Farnsworth@sheffield.ac.uk. 1.1: Realising novel machine design freedoms from innovative manufacture. 1.3. Manufacturing of light-weight and multi-functional structural components. 1.4. Manufacturing the novel and non-standard materials 2.2: Manufacturing high performance coils and ultimate control. 2.3: Manufacturing technologies for flexibility and customisation. X1: Sustainable manufacturing of electrical components for the circular economy. X2: In-process tracking and tractability for zero-defect manufacture of electrical machines. X3: Roadmapping and technology reviews X4: Demonstrator

https://www.facebook.com/FEMMhub/ https://www.linkedin.com/company/epsrc-future-electrical-machines-manufacturing-hub @FEMMhub Department of Electronic and Electrical Engineering, Sir Frederick Mappin Building, University of Sheffield, Mappin Street, Sheffield, S1 3JD. 91