Fraunhofer-Institut für Produktionsanlagen und Konstruktionstechnik IPK
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PublicationAnalyse und Nutzung von Aluminium-Bronze-Schleifstaub für das Laser-Pulver-AuftragsschweißenDie additive Fertigung verspricht ein großes Potenzial für den maritimen Sektor. Insbesondere Directed Energy Deposition (DED) Verfahren bieten die Möglichkeit, großvolumige maritime Bauteile wie Propellernaben oder -schaufeln herzustellen. Bei der Nachbearbeitung solcher Bauteile fällt in der Regel eine große Menge an Schleifabfällen an. Ziel des vorgestellten Projekts ist die Entwicklung einer nachhaltigen zirkulären AM-Prozesskette für maritime Komponenten auf Basis von Aluminiumbronze-Schleifresten. Dazu soll das Material wiederaufbereitet und anschließend als Rohmaterial für die Herstellung von Schiffspropellern im Laser-Pulver DED-Verfahren verwendet werden. In der vorliegenden Arbeit werden Schleifabfälle mittels dynamischer Bildanalyse untersucht und mit kommerziellem DED-Pulver verglichen. Anschließend werden Probengeometrien aus Schleifstaub gefertigt und durch metallographische Schliffe und REM/EDX analysiert.
PublicationTransferability of ANN-generated parameter sets from welding tracks to 3D-geometries in Directed Energy DepositionDirected energy deposition (DED) has been in industrial use as a coating process for many years. Modern applications include the repair of existing components and additive manufacturing. The main advantages of DED are high deposition rates and low energy input. However, the process is influenced by a variety of parameters affecting the component quality. Artificial neural networks (ANNs) offer the possibility of mapping complex processes such as DED. They can serve as a tool for predicting optimal process parameters and quality characteristics. Previous research only refers to weld beads: a transferability to additively manufactured three-dimensional components has not been investigated. In the context of this work, an ANN is generated based on 86 weld beads. Quality categories (poor, medium, and good) are chosen as target variables to combine several quality features. The applicability of this categorization compared to conventional characteristics is discussed in detail. The ANN predicts the quality category of weld beads with an average accuracy of 81.5%. Two randomly generated parameter sets predicted as “good” by the network are then used to build tracks, coatings, walls, and cubes. It is shown that ANN trained with weld beads are suitable for complex parameter predictions in a limited way.
PublicationAcoustic emission-based process monitoring in the milling of carbon fibre-reinforced plastics( 2022)
;Uhlmann, E.Holznagel, TobiasMilling of fibre-reinforced plastics is a challenging task. The highly abrasive fibres lead to high tool wear and coating failures, which cause increasing process forces and temperatures. Machining with a worn tool, in turn, can result in unwanted workpiece damages such as delamination or fibre protrusion. Reliable monitoring of the process must therefore be able to detect damages to the milling tool and the workpiece alike. The presented process monitoring approach measures the acoustic emission generated by the milling tool cutting edge entering the workpiece with a sensor attached to the tool holder. Specific acoustic emission frequency spectra and waveforms are emitted in the cutting zone for different tool wear states. Coating failures as well as other acoustic emission events due to workpiece damages can be robustly detected and distinguished by feature extraction and signal processing as well. The developed setup, the monitoring parameterisation techniques and signal processing algorithms as well as experimental and monitoring results are presented and discussed in this paper.
PublicationIntroducing readiness scales for effective reuse of open source hardware( 2022)
;Mies, Robert ;Hassan, MeheraOpen source hardware (OSH) describes physical products that allow for "anyone to study, modify, produce, and distribute them". While OSH principles aim to support design reuse, recent studies have challenged whether this is properly applied in practice. Therefore, this article delivers an assessment scheme that allows to identify the readiness of OSH designs for reuse. Testing the scheme on OSH ventilator designs collected by the Publnv ventilator project showed overall good usefulness of the scheme and emphasised the need of unambiguous assessment scales based on common standards. Less than two thirds of Publnv's listed projects fulfilled minimum criteria for openness.
PublicationMicro-texture dependent temperature distribution of CVD diamond thick film cutting tools during turning of Ti-6Al-4VMachining titanium alloys such as Ti-6Al-4V results in a high thermomechanical load on cutting tools and consequently short tool lifes. With respect to a necessary reduction of the resulting cutting tool temperatures, ultrashort pulse (USP) laser fabricated micro-textured rake faces offer direct supply of cooling lubricant into the cutting zone and lead to a reduced heat induction. As a result, micro-textured CVD diamond thick film cutting tools are also capable of machining high-performance materials due to reduced contact temperatures. In the scope of the research, the resulting temperature distribution for micro-textured rake faces will be compared under both dry and wet process conditions. Measurements show a reduction of the resulting cutting tool temperatures of Δϑt = 27.9 % using micro-textured cutting tools compared to non-textured cutting tools. A validated simulation provides valuable information about the contact temperatures enabling a specific development of the micro-texture geometry. As a result, a reduction of the contact temperature between chip and rake face by ΔϑT = 24.7 % was possible.
PublicationPotentials of Design Thinking for knowledge transfer of Model-Based Systems Engineering( 2022)
;Manoury, Marvin Michael ;Horländer, ToniZimmermann, ThomasIndustrial products are becoming increasingly complex due to the use and development of mechatronic systems. This increasing complexity is addressed by virtual representations of the systems in the form of interdisciplinary models. Model-Based Systems Engineering (MBSE) supports product development from the early development phase through validation, verification and integration up to later life cycle phases of the product by means of system modeling.Typical drivers for innovations in the industrial environment are business viability, technology driven feasibility and human driven desirability. While business viability and feasibility are considered in most product development processes and innovation driven projects, the human factor is often neglected in this context. This is addressed by a MBSE Capability and Maturation Matrix (CMM), which consists of capabilities for the acquisition and mastering of the MBSE competencies. The authors have considered Design Thinking as a feasible approach to transfer MBSE knowledge and thus support this acquisition MBSE competencies. This publication shall present the first findings on the application of Design Thinking for the creation of a user-centered MBSE introduction event. This event shall be used in further iterative steps to teach non-experts in the MBSE field the required competencies for their work and thus support the CMM development capability.
PublicationOptTopo: Automated set-point optimization for coupled systems using topology information( 2022)
;Thiele, Gregor ;Johanni, Theresa ;Sommer, David ;Eigel, MartinKrüger, JörgThe manufacturing sector has witnessed a rapid rise in the importance of energy-efficient operation. For finding optimal set-points for industrial facilities, optimization problems of increasing complexity occur. Key challenges are the leak of derivative information and the curse of dimensionality. For systematic reduction of the search-space by decomposition of the model, a methodology for the inclusion of topology knowledge in the optimization procedure is developed. An implementation of OptTopo (Optimization based on Topology), embedded in a testbed, demonstrates its advantages compared to popular out-of-the-box-optimization. OptTopo could be integrated in energy management software offering advanced set-point control for complex facilities.
PublicationInfluence of superimposed low frequency oscillations on single-pass honing of long-chipping steel( 2022)
;Uhlmann, E.Rozek, AndréSingle-pass honing is used as a finishing process to meet high demands regarding form and dimensional accuracy of drilled bores. The disadvantages of single-pass honing compared to the conventional long-stroke honing are high process forces and torques as well as an increased risk of chip space clogging of the abrasive stones. A significant reduction in process forces and torques can be achieved by superimposing the axial movement with oscillations. In this work the kinematic basics of different oscillation parameters and their effects on single-pass honing of long-chipping steel are analyzed. It can be concluded that by superimposing low frequency oscillations in single-pass honing, the process forces and torques as well as the specific energy consumption can be reduced significantly without a decline in surface quality and form accuracy.
PublicationResidual stress assessment during cutting tool lifetime of CVD-diamond coated indexable inserts( 2022)
;Uhlmann, E.Hinzmann, DanielInsufficient coating adhesion limits reproducibility regarding tool lifetime as well as workpiece quality during the application of CVD-diamond coated cutting tools. Depending on the combination of tungsten carbide substrate material, coating thickness as well as coating morphology, individual residual stress conditions exist within CVD-diamond coated cutting tool specifications. The application of these tools is accompanied by coating delamination as primary cutting tool failure. The tool lifetime of the respective cutting tool composition depends on the corresponding residual stress condition until crack development within the CVD-diamond coating initiates tool failure. During external cylindrical turning of hypereutectic aluminium silicon alloy AlSi17Cu4Mg-T6 the residual stress condition of a CVD-diamond coated cutting tool is assessed along the cutting edge, the rake face as well as flank face throughout the respective tool lifetime. Consequently, the progression of the residual stress condition until cutting tool failure regarding coating delamination is observed. During the tool lifetime of the investigated CVD-diamond cutting tools, compressive residual stress ∆σR,c shifts to tensile residual stress ∆σR,t underneath the cutting edge corner. The approximated residual stress difference of ∆σR ≈ 5 GPa indicates stress peak relaxation processes, such as crack initiation, within the CVD-diamond coating.
PublicationIntuitive Interaktion mit Strukturdaten aus einem PLM-System( 2012)
; ;Wolter, Lars ;Hayka, HaygazunRöhlig, MartinDie Tätigkeit des Ingenieurs im Bereich der virtuellen Produktentwicklung betrifft neben dem Entwurf und der Absicherung einer dreidimensionalen Produktgeometrie auch die Erstellung, Analyse und Veränderung von strukturierten Produktinformationen. Dabei handelt es sich in erster Linie um Anforderungs-, Funktions- oder Produktstrukturen, welche innerhalb unterschiedlicher Phasen des Produktentstehungsprozesses in einem PLM-System verwaltet werden. Die Produktstruktur nimmt häufig einen zentralen Stellenwert ein, da sie als digitales Grundgerüst und Referenzstruktur innerhalb der Produktentwicklung gilt. Die Anzahl der strukturell organisierten Einzelteile und Dokumente für ein Produkt können je nach Sparte bis über 1.000.000 Elemente einnehmen (Carneo 2010), welche in mehreren Baugruppen über verschiedene Hierarchiestufen zusammengehalten werden. In der Produktstruktur werden zu dem unterschiedliche Varianten des Produktes über Konfigurationsregeln organisiert. Unter dem zusätzlichen Aspekt der zeitlichen Dynamik bei den Iterationszyklen des Entwicklungsprozesses kann für der Produktstruktur von einem komplexen Informationsgebilde gesprochen werden.