Electric Hybrid Motor Aerospace Case Study

02/19/2021

An aerospace EV developer approached Laser Technologies with a cutting edge design for a propulsion motor using  thin gauge (0.004”) lamination material. The segmented stator design involved complex geometry and thin back iron. The final assembly needed to be stacked with minimum movement or out of position features, and required the laminations to lay as flat as possible to minimize bonding stresses.

The high alloy material underwent a lot of stress from rolling, compaction, heating and cooling due to the various processes required to manufacture the raw material. When this material is sheared and sheeted, laser cut or stamped, these stresses can be magnified, and producing a satisfactory finished part becomes a tremendous challenge. 

Upon initial test runs, the segmented laminations had a tendency to want to curl up on itself causing fingers to close up on the slot dimensions. Laser Technologies’ engineers developed a solution that involved multiple processes to manage the material stress. Laser cutting was done first, followed by a pre-annealing process to flatten the parts. Upon completion of the first anneal, parts were magnetically tested and verified against customer requirements. After testing, a secondary annealing process was implemented to ensure optimum magnetic properties were met. 

After annealing a final process was executed to apply a microns thick layer of C5 insulating coating to a finished part that was approximately 9” in length and 0.0004” thick. The coating thickness also had to be measured and maintained in order to adhere to extremely tight tolerances across the part. 

After everything was successfully manufactured, the final challenge involved packaging and delivering the flimsy thin back iron laminations to the customer without incurring any damage. Laser Technologies has in-house capabilities to design and procure customer specific packaging utilizing foam-in-place, custom crating, desiccants and VCI paper to ward off moisture. Some customers require 3-5 years of shelf-stable parts which require delivering the parts in vacuum sealed bags. 

Laser Technologies' 35 years of experience manufacturing laminations contributed to the successful completion and delivery of very complex, fragile thin back iron parts to their customer.