Conventional design of the steel cast bracket (upper left) that
was environmentally assessed against the corresponding topology-optimized design of the EOS titanium AM-made bracket (lower right corner). Source: Airbus Group Innovations.
Conventional design of the steel cast bracket (upper left) that was environmentally assessed against the corresponding topology-optimized design of the EOS titanium AM-made bracket (lower right corner). Source: Airbus Group Innovations.

They companies compared the lifecycle of a generic bracket benchmarking the DMLS process with a conventional casting process, and found that  the use phase has by far the biggest impact in terms of energy consumption and CO2 emissions over the whole lifecycle of the bracket. CO2 emissions over the whole lifecycle of the nacelle hinges were reduced by nearly 40% via weight saving using DMLS, and the weight per plane could be reduced by up to 10 kilogrammes.

When using as an example a titanium bracket made using DMLS, the companies found that total energy consumption for creating the initial raw powder metal, then producing the bracket in DMLS, was slightly smaller than the equivalent cast process steps (with the higher energy use of DMLS limited to the melt and chill cycle of its manufacturing profile and offset at the same time by a significantly reduced build time). 

Casting in this comparison also included the furnace operation of burning a stereolithography (SLA) epoxy model, which uses more energy and generates greenhouse gases.

The DMLS process itself used only the material actually needed to make the part – eliminating waste from secondary machining and reducing consumption of titanium by 25% over the cast application.

“DMLS has demonstrated a number of benefits, as it can support the optimization of design and enable subsequent manufacture in low-volume production,” said Jon Meyer, additive layer manufacturing research team leader, in his final report. “In general, the joint study revealed that DMLS has the potential to build light, sustainable parts with due regard for the company’s CO2 footprint.”