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Univ. Prof. Dr. Ing.
Bergs, Thomas
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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)
;Li, Yupeng ;Boseila, JonasSchleifenbaum, Johannes HenrichIn 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. -
PublicationAn optimization approach for a milling dynamics simulation based on Quantum Computing( 2024-02-01)
;Danz, Sven ;Kienast, Pascal ;König, ValentinaSince the machining of complex aerospace components, like integral compressor-rotors (blade integrated disks), is very cost-intensive, optimizing the process by means of process simulations is an active field of research. With the rise of Quantum Computing, a new instrument with high optimization potential is moving into focus. In this paper, a possible application of Quantum Computing for the machining simulation of multi-axis milling of thin-walled aerospace components is discussed. For this reason, a simulation framework used for the milling simulation is analyzed and each component is evaluated separately in relation to Quantum Computing. Parts of the Harrow, Hassidim, and Lloyd algorithm are proposed to enhance the Finite-Element simulation-based component, like the modal analysis for dynamics simulation. This algorithm can solve linear system problems with exponential speed-up over the classical method. The paper presents a roadmap on how the classical steps of a modal analysis for dynamics simulation could be replaced by quantum algorithms based on quantum phase estimation. The implementation of the first working steps is presented to validate this approach. The linear system problem, arising from the dynamics simulation, is analyzed in detail and a minimal value problem of linear coupled oscillators is derived. -
PublicationBlisk Specific Query Language (BLISQL) - An approach for domain specific data querying in Blisk Manufacturing( 2023-07-18)
;Vinogradov, GeorgProduct 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. -
PublicationCloud-based process design in a digital twin framework with integrated and coupled technology models for blisk milling( 2022-12-19)
;Kienast, Pascal ;Vinogradov, GeorgIn this publication, the application of an implemented Digital Twin (DT) framework is presented by orchestration of CAM-integrated and containerized technology models carrying out FEM-coupled simulations for the finishing process of a simplified blade integrated disk (blisk) demonstrator. As a case study, the continuous acquisition, processing and usage of virtual process planning and simulation data as well as real machine and sensor data along the value chain is presented. The use case demonstrates the successful application of the underlying DT framework implementation for the prediction of the continuously changing dynamic behavior of the workpiece and according stable spindle speeds in the process planning phase as well as their validation in the actual manufacturing phase. -
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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PublicationKnowledge-Based Process Design Optimisation in Blisk Manufacturing( 2022)
;Vinogradov, GeorgThe manufacturing process of blade-integrated disks (blisks) represents one of the most challenging tasks in turbomachinery manufacturing. The requirement is to machine complex, thin-walled blade geometries with high aspect ratios made of difficult-to-cut materials. In addition, extremely tight tolerances are required, since the smallest deviations can lead to a reduction in efficiency of the blisk in the later use. Nowadays, the ramp-up phase for the manufacturing of a new blisk is time and cost intensive. To find a suitable manufacturing process that meets the required tolerances of the blisk, many experimental tests with different process parameters and strategies are necessary. The used approach is often trial and error which offers limited testing opportunities, is time consuming and wastes resources. Therefore, the objective of this paper is to develop a knowledge-based process design optimization in blisk manufacturing. For this purpose, this paper picks up the results from our previous work. Based on these results, an experimental validation of the two process design tasks "number of blocks"and "block transition"is conducted. As part of the validation, the results of machining tests on a demonstrator blisk made of Inconel 718 are presented and discussed. -
PublicationInvestigations on five-axis milling and subsequent five-axis grinding of gears( 2022)
;Janßen, Christopher ;Jahnel, KirkBrimmers, JensHigh-productivity processes such as gear hobbing and gear grinding are normally used in the manufacturing of gears. In some applications, however, the use of these processes is not possible due to accessibility. One example is the production of planetary gears with double helical teeth for the gear box in modern aircraft engines. The gear boxes are used to increase the efficiency of the engines but should be as light and compact as possible. Thus, the tool runout area for gear hobbing or gear grinding tools is too small. One way of manufacturing these gears is five-axis machining. While five-axis milling of gears has been the subject of several publications, five-axis grinding of gears has hardly been a topic. This paper presents the results of investigations on five-axis milling and subsequent five-axis grinding of gears in comparison to conventionally manufactured gears. For this purpose, after hardening, gears were first five-axis milled and then five-axis ground using different process parameters and then investigated on back-to-back test rigs regarding load carrying capacity. In addition, the dimensional accuracy was measured and the surfaces were examined metallographically. The dimensional accuracy became worse after five-axis grinding. However, in terms of gear life, the five-axis milled and then five-axis ground variant showed an increase of 8.2 % compared to the conventionally manufactured gear which indicates a high potential for further research in regard to the presented five-axis machining process chain of gears. -
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-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).