Challenge

Using additive manufacturing to optimise and lightweight motor casings.

Background

The conventional manufacturing of electric motor casings, typically involving die casting and CNC machining, presents several challenges. This multi-stage process can be energy-intensive, may not utilise material in the most efficient way and can restrict the ability to design complex, lightweight components.

Additive manufacturing (AM) offers a different approach to component production, allowing for greater design freedom and the potential for part consolidation. By building components layer by layer, AM can enable the creation of intricate geometries and integrated features that might be difficult or impossible to achieve with traditional methods.

This project investigated the application of AM to redesign an existing electric motor casing with the aim of optimising its weight and functionality, while incorporating necessary mounting brackets and spiral cooling channels. The original design space, loading conditions and applied material were considered as the basis for the AM redesign.  

Innovation

The core of this project involved redesigning the motor casing specifically for additive manufacture. This optimisation considered a system-level approach to explore opportunities for part consolidation and multi-functional use. Support brackets, which would typically be separate components, were organically incorporated into the motor case as a single, unified body.

An in-house algorithm was developed to morph the integrated liquid cooling channel geometry to suit the manufacturing constraints of the AM process used, and potentially achieve greater thermal control. Digital datasets were collected throughout the project to enable a direct comparison of the AM-produced component with those manufactured using conventional processing methods.

Result

A full-sized electric motor casing with integrated mounting brackets and cooling channels was successfully fabricated in a single AM build. This result is particularly impressive as the tortuous cooling channel path was manufactured without the inclusion of any additional internal support structures.

This result proves the effectiveness of the in-house developed algorithm and its viability for use in thermal management future motor casing applications.

The successful incorporation of support brackets and cooling channels into a single AM component also demonstrated the possibility of part consolidation and weight reduction for electric machine casings, and a potential route towards quicker assembly times and lower system costs.

Impact

If the UK is to truly make electric flight a reality in the next 15 years, manufacturers will need to find a way to vastly improve the continuous power density of electrical machines.

This innovation, an optimised motor casing, will allow more efficient and power-dense electrical machines to be manufactured.

By exploring the use of AM to create lighter, more integrated and potentially better-cooled motor casings, this project contributes to the advancement of more efficient and power-dense electric motors, which are crucial for applications like electric flight and beyond. The principles demonstrated could also be applicable to optimising motor casings for other industries.