Direct Plating Could Reduce Rotor Blade Cost and Weight

Alpha Metalcraft Group (AMG) believes it can reduce the cost and complexity of specialist manufacturing tasks such as applying the leading-edge guards that prolong the service life of carbon-fiber rotary blades. The company is working with OEMs, including developers of eVTOL aircraft, to introduce an electroplating process in which nickel is directly deposited on composite surfaces rather than making the guards separately and then fitting them to the blades.

The current process involves expensive stainless steel mandrel forms for shaping the nickel abrasion guards. This approach is also time-consuming, with five separate steps plus two or more transportation stages to get the finished items installed on the blades.

Mandrels produced to duplicate the shape of the rotorblade can cost up to $100,000 apiece. According to AMG engineering director Luigi Cazzaniga, as many as 80 mandrels might be needed for various parts of an eVTOL and, in his view, some of the advanced air mobility sector start-ups have not yet fully considered this or other aspects of preparations for high-volume manufacturing.

“By moving to direct composite plating, we can make the trailing edge as thin as we like, which will also mean weight savings for the aircraft,” Cazzaniga explained. “The ability to directly plate a nickel substrate onto a carbon-filled composite structure eliminates the need for multiple assembly processes and can lower overall manufacturing costs.”

With proof-of-concept engineering work now complete, AMG is partnering with M4 Engineering to make composite panels onto which metal layers that could include lightning-strike protection can be electro-deposited. The metal guard can be exposed by abrasion techniques with the nickel and copper layers bonded and embedded into the composites. Essentially, the composite blade acts as its own mandrel.

By April, the Connecticut-based company expects to be ready to take the next step with a manufacturing partnership. AMG is open to business models that could include licensed manufacturing or establishing facilities close to aircraft OEMs. With certification issues still to be resolved, Cazzaniga estimated that it could take another 12 to 18 months to achieve full-scale production for the new process.

AMG’s engineering team has conducted strength tests on various direct plating samples to identify specific failure points. This work has led the company to improve the surface abrasion process.