How High-Tolerance, High-Volume Stator and Rotor Manufacturing is Transforming eVTOL Motors

The aerospace industry stands on the cusp of a revolution, with Electric Vertical Takeoff and Landing (eVTOL) aircraft promising to reshape urban mobility.

A critical challenge lies at the heart of this transformation: manufacturing high-performance electric motors at scale. Carpenter Electrification is leading the charge in overcoming long standing hurdles in processing iron cobalt stacks, bridging the gap between high-volume production and the stringent tolerances required for aerospace applications.

The Historical Challenge: Balancing Volume and Precision

For decades, the aerospace industry has grappled with a seemingly insurmountable trade-off: achieving high-volume production of power dense motors while maintaining the tight tolerances essential for optimal motor performance.

Traditional methods of processing iron cobalt stacks faced significant hurdles, including:

• Changes during annealing: Iron cobalt materials undergo dimensional changes during the heat treatment process, leading to potential distortions in the final product.
• Costly post-processing: Extensive grinding or EDM machining was often required to achieve the necessary tolerances of the stator rotor outer diameter, driving up costs and reducing efficiency.
• Limited copper fill: Imprecise stacking methods resulted in lower copper fill factors, with stator windings compromising motor power output.
• Volume constraints: High-precision methods like EDM cutting were prohibitively slow for high-volume production.

Carpenter Electrification's Advanced, Integrated Stack Production Technology

Carpenter Electrification has advanced alloy and stack processing technologies to solve these longstanding challenges. Our state-of-the-art capabilities at each stage of our integrated process enable the production of iron cobalt stacks, from prototype development through high-volume manufacturing.

Key capabilities and advancements include:

• Hiperco® alloy: Our industry leading iron-cobalt alloy family features chemistries tailored for low core loss, high strength, or a balance of properties.
• Controlled strip processing: Our precision strip hot rolling mill enables highly repeatable processing and consistent surface finish and quality.
• Advanced stack processes: From producing laminations through heat treating, assembly, and bonding we have developed and integrated the latest techniques to improve stack dimensional tolerance and magnetic performance.
• High volume stacking: A new assembly process within a controlled environment improves stack productivity, quality, and repeatability
• Comprehensive testing: Advanced magnetic performance tests ensure every stack meets exacting standards.

The Impact on eVTOL Motor Performance

These advancements translate directly into superior motor performance for eVTOL applications. Applications and companies will benefit from:

• Tighter tolerances: eVTOL motor designers are targeting profile tolerances of 0.002 inches, significantly improving over the industry standard of 0.006-0.008 inches.
• Higher power density: Improved stacking, smaller air gaps, and higher copper fill factors lead motors to deliver more power in the same footprint.
• Consistent performance: Our ability to maintain tight tolerances across high-volume production runs ensures consistent motor performance, which is critical for the safety and reliability demands of aerospace applications.
• Production at scale: Expected eVTOL demand will require high volumes of stator and rotor stacks for the electric propulsion units.  Carpenter Electrification's manufacturing processes have been developed to produce these tight tolerance, high power density, and repeatable stacks at scale."

Paving the Way for the Future of Aerospace

As the eVTOL market accelerates, the demand for high-performance motors is set to increase. Carpenter Electrification's advancements in high-tolerance, high-volume manufacturing position us at the forefront of this revolution. Our comprehensive approach — encompassing alloy development, precision stamping, automated assembly, and rigorous testing — provides a robust foundation for the next generation of aerospace motors.

Reach Out to Learn More

The aerospace industry is at a pivotal moment, with eVTOL aircraft promising to reshape our skies. At Carpenter Electrification we are developing the technology to help make this dream a reality. Our breakthroughs in high-tolerance, high-volume manufacturing of stator and rotor stacks are setting new standards for motor performance, reliability, and cost-effectiveness.

Are you ready to take your aerospace motor designs to new heights? Contact Carpenter Electrification today to learn how our advanced stator and rotor stacks can propel your eVTOL projects further.