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PublicationLife cycle analysis results for engine blisk LCA( 2024-02-05)Purpose - The aviation industry has seen consistent growth over the past few decades. To maintain its sustainability and competitiveness, it is important to have a comprehensive understanding of the environmental impacts across the entire life cycle of the industry, including materials, processes and resources; manufacturing and production; lifetime services; reuse; end-of-life; and recycling. One important component of aircraft engines, integral rotors known as Blisks, are made of high-value metallic alloys that require complex and resource-intensive manufacturing processes. The purpose of this paper is to assess the ecological and economical impacts generated through Blisk production and thereby identify significant ‘hot-spots’. Design/methodology/approach - This paper focuses on the methodology and approach for conducting a full-scale Blisk life cycle assessment (LCA) based on ISO 14040/44. Unlike previous papers in the European Aerospace Science Network series, which focused on the first two stages of LCA, this publication delves into the "life cycle impact assessment" and "interpretation" stages, providing an overview of the life cycle inventory modeling, impact category selection and presenting preliminary LCA results for the Blisk manufacturing process chain. Findings - The result shows that the milled titanium Blisk has a lower CO2 footprint than the milled nickel Blisk, which is less than half of the global warming potential (GWP) of the milled nickel Blisk. A main contributor to GWP arises from raw material production. However, no recycling scenarios were included in the analysis, which will be the topic of further investigations. Originality/value - The originality of this work lies in the detailed ecological assessment of the manufacturing for complex engine components and the derivation of hot spots as well as potential improvements in terms of eco-footprint reduction throughout the products cradle-to-gate cycle. The LCA results serve as a basis for future approaches of process chain optimisation, use of "greener" materials and individual process improvements.
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PublicationMachinability study in orthogonal cutting of additively manufactured Inconel 718 with specifically induced porosity( 2024-02-01)In comparison to conventional manufacturing technologies, additive manufacturing (AM) offers great design freedom, the integration of functions into components, new lightweight design concepts and high material efficiency. In aerospace and turbomachinery, this technology is increasingly coming into focus, especially the laser-based powder bed fusion of metals (PBF-LB/M) process. PBF-LB/M is already used for some aerospace components, which are often exposed to high thermal and mechanical loads. Dependent on the component geometry, support structures are required for AM, which then usually have to be removed by machining. One suitable support structure is the use of material with specifically induced porosity. This ensures good heat dissipation and thus homogeneous component properties, high retention forces and short process times in PBF-LB/M. However, the machinability of porous, additively manufactured material has hardly been researched so far. One preliminary investigation of milling porous, additively manufactured Inconel 718, though, showed significantly poorer machinability of the porous material compared to the dense material. To further examine this phenomenon, this paper presents the results of fundamental machinability studies with porous, additively manufactured Inconel 718 in orthogonal cutting. The investigations with tungsten carbide cutting tools on a special fundamental test rig include the analysis of the cutting force, the chip geometry, the chip temperature and the surface quality. The research results provide explanations for the poorer machinability of the porous material and derived approaches for improving the machinability in future studies.
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PublicationAn optimization approach for a milling dynamics simulation based on Quantum Computing( 2024-02-01)
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PublicationBlisk Specific Query Language (BLISQL) - An approach for domain specific data querying in Blisk Manufacturing( 2023-07-18)Product lifecycle management (PLM) is constantly improved by a steadily growing amount of data collected along the product and process development chain. This data supports designing optimized geometries and manufacturing processes. For the optimization of the manufacturing process, data from process design and manufacturing are extracted and processed. The use of a query language is helpful to make the extraction more efficient. Query languages, referring to the specific domain of a component, simplify the formulation of the queries. We present an approach for domain specific data querying in blisk manufacturing based on the Resource Description Framework (RDF) using SPARQL.
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PublicationCloud-based process design in a digital twin framework with integrated and coupled technology models for blisk milling( 2022-12-19)
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PublicationResilience in Aviation( 2022-11-14)Pandemic, sustainability and efficiency targets pose ongoing challenges for the aviation industry: It must continue to develop propulsion concepts and tap into new materials and manufacturing processes. Cross-domain digital twins harbor previously untapped potential for mastering growing requirements with the help of digitization, as a practical example from the production of aerospace components shows in the white paper. The trend topic of sustainability drives innovation and complements productivity, quality and costs as criteria for strategic corporate decisions. Awareness of this must be consolidated among personnel, as well as the ability to manage resilient processes. Such processes ensure the successful handling of disruptions. In this way, a disruption can even turn into an opportunity. In the white paper, the Fraunhofer IPT pools its expert knowledge on how the dimensions of "technology", "digitalization", "sustainability" and "employees" can be combined in the context of aviation in order to seize this opportunity.
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PublicationResilienz in der Luftfahrt( 2022-09-16)Pandemie, Nachhaltigkeits- und Effizienzziele stellt fortlaufende Herausforderungen an die Luftfahrtindustrie: Sie muss Antriebstechnologien weiterentwickeln sowie neue Werkstoffe und Fertigungsverfahren erschließen. Domänenübergreifende digitale Zwillinge bergen bisher ungenutzte Potenziale, um wachsende Anforderungen mithilfe von Digitalisierung zu bewältigen, wie ein praxisnahes Beispiel aus der Fertigung von Luftfahrtkomponenten im Whitepaper aufzeigt. Das Trendthema Nachhaltigkeit treibt Innovationen an und ergänzt Produktivität, Qualität und Kosten als Kriterium für strategische Unternehmensentscheidungen. Das Bewusstsein dafür muss sich beim Personal festigen sowie die Fähigkeit, resiliente Prozesse zu bewältigen. Solche Prozesse stellen den erfolgreichen Umgang mit Störungen sicher. So kann sich eine Störung sogar zu einer Chance wandeln. Das Fraunhofer IPT bündelt im Whitepaper sein Expertenwissen, wie sich die Dimensionen »Technologie«, »Digitalisierung«, »Nachhaltigkeit« und »Personal« im Kontext der Luftfahrt verbinden lassen, um diese Chance zu ergreifen.
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PublicationPreparation of Papers for IFAC Conferences & Symposia: Adaptive fixture system for reducing machining distortion caused by residual stresses in milling( 2022)Machining distortion caused by residual stresses is one of the major challenges in the production of thin-walled monolithic parts, which are widely used in the aerospace industry. The relevant influencing factors include the selected process parameters, the machining sequence as well as the used fixture system. This paper presents an adaptive fixture system for reducing machining distortion caused by residual stresses in milling. To validate the advantage of this system, machining distortion experiments are conducted on monolithic parts made of Ti-6A1-4V using a conventional and the adaptive fixture system.
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PublicationLife-Cycle-Assessment for Rough Machining of Inconel 718 Comparing Ceramic to Cemented Carbide End Mills( 2022)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-tomachine 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).
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PublicationMachinability analysis for milling of additively manufactured Inconel 718 with specifically induced porosity( 2022)Compared to conventional manufacturing technologies, additive manufacturing (AM) offers great design freedom, the integration of functions into components, new lightweight construction concepts and high material efficiency. This technology is increasingly coming into focus in aerospace and turbomachinery engineering, especially the Laser Powder Bed Fusion (LPBF) process. LPBF is already being used for some aerospace components that are often subject to high thermal and mechanical loads. Depending on the component geometry, support structures are required for additive manufacturing, which then have to be removed, usually by machining. Among others, the use of material with specifically induced porosity is suitable as a support structure. This ensures good heat dissipation and thus homogeneous component properties, high retention forces and short process times in the LPBF process. However, the machinability of porous, additively manufactured material has hardly been researched to date. This paper therefore presents the results of machinability investigations with porous, additively manufactured Inconel 718. The investigations included the analysis of active cutting force, cutting tool wear, surface finish and chip geometry in the milling process with tungsten carbide cutting tools. It was found that with the porous material, the dominant type of wear is early starting chipping of the cutting tool edges. The active force decreases with increasing porosity. Partial smearing of the pores was observed on the milled surfaces. The chips of the porous material show a disrupted surface. In future investigations, the aim is to improve the wear behaviour when milling porous Inconel 718.
