Multipole Magnetic Rotor for Aerospace

By Paul Fears | 29 January 2020

Bunting has secured an order for the supply of 300 multi-pole Samarium Cobalt (SmCo) magnetic rotors annually to a prominent aerospace customer. The magnetic rotor order was placed at the end of 2019 with deliveries starting in 2020 and running for 10 years.

The Bunting engineering team has worked with this aerospace customer for a number of years. The new order was placed after a 12-month period of close co-operation between the two companies quality and production teams identifying and implementing improvements to manufacturing processes for compliance with strict aerospace regulations.

Magnetic Rotor Technology
Multi-pole magnetic rotor

The Magnetic Rotor Technology

This multi-pole SmCo rotor is assembled un-magnetised with four pure arc magnets secured using a high-temperature adhesive. Samarium Cobalt is a permanent rare earth magnet material that outperforms other high strength magnets, such as Neodymium, above 150 degrees Celsius. SmCo has excellent resistance to corrosion and is used widely in the aerospace, military, and automotive industries.

Once the magnets are fixed into position, the assembly is then precision ground on the outer diameter and bearing surfaces. Following the grinding operation, a metallic retention sleeve is a heat shrunk onto the outer diameter of the magnet, before attaching the shaft and end collars. Sleeving the magnetic rotor prior to magnetisation allows for a higher elevated temperature during the sleeving process without permanent loss to the magnetic strength. The result is a higher pre-stress on the magnets, which allows a higher operational rotation speed.

The rotor sleeve is then machined back to a thickness of 0.15mm before being cleaned prior to magnetisation. The magnetic rotor assembly is magnetised in a bespoke Bunting designed and built post-assembly magnetising fixture. Following magnetic saturation tests, the magnetic rotors are packed ready for despatch.

Meeting Aerospace Requirements

In order to meet the ongoing customer’s required usage, Bunting has increased the stock position of semi-finished and finished components.

In order to smooth out potentially price volatility of SmCo magnets over the term of the project, the customer provided initial funding and future order cover to forward purchase key raw materials.

Samarium Cobalt Magnets
Samarium Cobalt Magnets

This latest aerospace project reflects the magnet engineering expertise of the Bunting team at Berkhamsted, UK. Bunting supplies magnetic materials and magnetic assemblies for many commercial and military aerospace partners with some bespoke components supplied into the satellite industry.

Bunting design and manufacture a wide range of magnetic separators, metal detectors, magnets and magnetic assemblies.  Many are bespoke for specific applications.  For further information on bespoke magnet assemblies or magnet designs, please contact us via:

Phone:  +44 (0) 1442 875081


Via the Bunting-Berkhamsted website for specialist magnets and magnetic assemblies

Via Bunting-eMagnets for online purchase of Magnets and Magnetic Technology

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