Environmental Impact Assessment of Direct Energy Deposition (DED)

Sustainable manufacturing

The MTC demonstrated the use of DED for both complex component builds and part repairs through this propeller blade case study. The technologies were assessed on their environmental impact benchmarked against traditional manufacturing methods

the challenge

Current casting methods for propeller blade manufacturing generate large amounts of waste. A near net shape DED manufacturing process has the potential to therefore reduce the environmental impact during the manufacturing phase.

Alongside the challenge of building these components, propeller blades are highly susceptible to corrosion in service, limiting their use life to an average of 5 years. DED offers a viable repair mechanism for these parts, providing a means to increase this lifespan, thus reducing the demand for virgin components. However, analysis is required to understand the ‘in process’ environmental impact of this repair method compared to the potential benefits of life extension.

mtc's solution

• The MTC produced a propeller blade using wire arc additive manufacturing (WAAM), with the build validated against the programmed CAD model using the MTC’s state of the art metrology equipment. During the build, the resources required for the process were monitored providing the necessary information to calculate the environmental impact of the process.

• The repair of the blade was then performed using wire fed laser DED, where defects on the leading edge and top edge were accurately repaired (see above images). The environmental monitoring conducted on the build was then repeated on the repair, providing an indication of the life extension required to offset the environmental inputs of the repair.

the outcome

• Near net shape propeller blade manufactured and repaired using wire fed DED processes.

• Calculation of the environmental impact of both processes, with identification of ‘hot spots’ where improvements to the process could be made from an environmental perspective.

• An end to end methodology for assessing a manufacturing processes environmental impact which can be used across the MTC and industrially.

Benefits to the client

• A business case for the adoption of DED processes for industry to harness both performance and environmental sustainability benefits.

• Up to 35% reduction in embodied carbon emissions per propeller blade manufacture through the use of DED compared to investment casting.

• Energy efficiency recommendations were made which could reduce the energy consumption of the build process, and in turn reduce the cost of electricity, by up to 73.69%.

• Capability to calculate the environmental impact of further manufacturing processes to aid industry in making informed decisions regarding sustainability.