Air traffic is expected to double over the next 20 years and Flightpath 2050 targets to a 70 % reduction of CO2 and a 90 % reduction of NOx. Optimization of future aircraft engines often is dominantly driven by a focus on the reduction of fuel burn and emissions during operation. To identify additional environmental improvement potential a full Life Cycle Analysis (LCA) shall be aspired also including Materials, Processes and Resources, Manufacture and Production, Lifetime Services as well as Reuse, End-of-Life and Recycling. Core engine components, for example integral rotors, are comprised of Titanium-or Nickel-alloys and require complex manufacturing processes. A geometry design model of a compressor blisk is introduced which is employed as basis for a future LCA approach focusing on materials, processes and resources as well as manufacture and production. The model is a carrier for challenging manufacturing features such as large blade twist, high aspect ratio and small blade gaps. In addition to the geometry model, a first set of multiple technology scenarios and their process chains will be introduced which will serve as base for a future LCA.

The aviation industry has been growing continuously over the past decades. To ensure sustainability and competitiveness for the aviation industry sector, a full understanding of the environmental impacts is required, not only during use phase but along the entire life cycle, including “Materials”, “Processes and Resources”, “Manufacturing and Production”, “Lifetime Services” as well as “Reuse, End-of-Life and Recycling”. Core engine components, such as integral rotors (Blisks), are comprised of high value metallic alloys that require complex and resource consuming manufacturing processes. This paper will introduce an approach for Life-Cy-cle-Inventory data acquisition during Blisk manufacturing as basis for a Life-Cycle-Assessment (LCA) according to ISO 14040. A particular focus will be set on the data quality and confidence level regarding measuring, acquisition, and analysis of in- and output flows within the Blisk manufacturing process chain in scope. This includes the stages of material generation, forming processes, heat treatments, machining, surface treatments and quality assurance. A greater emphasis is drawn to selected variations on mechanical machining processes. On this basis, first results of an LCA for Blisk-manufacturing will be presented.

The aviation industry has been growing continuously over the past decades. Despite the current Covid-19 crisis, this trend is likely to resume in the near future. On an international level, initiatives like the Green Recovery Plan promoted by the European Union set the basis towards a more environmentally friendly future approach for the aero-industry. The increasing air traffic and the focus on a more sustainable industry as a whole lead to an extensive need for a more balanced assessment of a products life cycle especially on an ecological level. Blisks (or IBRs) remain a central component of every current and very possible every future aero engine configuration. Their advantages during operation compared to conventional compressor rotors are met with a considerably complex manufacturing and production process. In the high-pressure compressor segment of an engine, the material selection is limited to Titanium alloys such as Ti6Al4V and heat-resistant Nickel-alloys such as Inconel718. The corresponding process chains consist of numerous different process steps starting with the initial raw material extraction and ending with the quality assurance (cradle to gate). Especially the central milling process requires a highly qualified process design to ensure a part of sufficient quality. Life-Cycle-Assessments enable an investigation of a products overall environmental impact and ecological footprint throughout its distinct life-cycle. Formal LCAs are generally divided by international standards into four separate steps of analysis: the goal and scope definition, the acquisition of Life Cycle-Inventory, the Life-Cycle-Impact-Assessment and the interpretation. This content of this paper focuses on a general approach for Life-Cycle-Assessment for Blisk manufacturing. • Firstly, the goal and scope is set by presenting three separate process chain scenarios for Blisk manufacturing, which mainly differ in terms of raw material selection and individual process selections for blade manufacturing. • Secondly, the LCI data (Life-Cycle Inventory) acquisition is illustrated by defining all significant in- and outputs of each individual process step. • Thirdly, the approach of a Life-Cycle-Impact-Assessment is presented by introducing the modelling approach in an LCA-software environment. • Fourthly, an outlook and discussion on relevant impact-indicators for a subsequent interpretation of future results are conducted.

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Nickel-based alloys such as Inconel 718 belong to the group of heat-resistant super alloys. Combined with good mechanical properties over a wide range of temperatures nickel alloys are used extensively in the aero engine sections exposed to elevated temperatures. Besides turbine blades and discs, integrally designed compressor rotors (Blisks) in the high-pressure compressor (HPC) are increasingly made of Ni-alloys. This is the result of an efficiency-driven increase in temperature levels in the rear compressor stages. The machining of these hard-to-machine materials is characterized by low productivity and high tool wear. Compared to the machining with conventional cemented carbide end mills, innovative SiAlON ceramics offer a significant potential to increase the performance of these machining processes while saving cooling-lubricants. Besides an increase in productivity, the evaluation of the overall environmental impact of specific manufacturing processes is gaining importance in the context of more sustainable product life-cycles. This paper focuses on the comparison of different milling strategies in the production of high-pressure compressor rotors made from Inconel 718 in a cradle-to-gate assessment based on DIN EN ISO 14040/44. Thus, the ecological impact of both the state-of-the-art and the novel SiAlON roughing strategy are evaluated considering the consumption of energy, water and compressed air as well as the tool wear. The Life-Cycle-Impact-Analysis (LCIA) will be performed as a midpoint analysis taking multiple indicators into account such as the Global Warming Potential (GWP).

Nickel-based alloys such as Inconel 718 belong to the group of heat-resistant super alloys. Combined with good mechanical properties over a wide range of temperatures nickel alloys are used extensively in the aero engine sections exposed to elevated temperatures. Besides turbine blades and discs, integrally designed compressor rotors (Blisks) in the high-pressure compressor (HPC) are increasingly made of Ni-alloys. This is the result of an efficiency-driven increase in temperature levels in the rear compressor stages. The machining of these hard-to-machine materials is characterized by low productivity and high tool wear. Compared to the machining with conventional cemented carbide end mills, innovative SiAlON ceramics offer a significant potential to increase the performance of these machining processes while saving cooling-lubricants. Besides an increase in productivity, the evaluation of the overall environmental impact of specific manufacturing processes is gaining importance in the context of more sustainable product life-cycles. This paper focuses on the comparison of different milling strategies in the production of high-pressure compressor rotors made from Inconel 718 in a cradle-to-gate assessment based on DIN EN ISO 14040/44. Thus, the ecological impact of both the state-of-the-art and the novel SiAlON roughing strategy are evaluated considering the consumption of energy, water and compressed air as well as the tool wear. The Life-Cycle-Impact-Analysis (LCIA) will be performed as a midpoint analysis taking multiple indicators into account such as the Global Warming Potential (GWP).