Fraunhofer-Institut für Produktionsanlagen und Konstruktionstechnik IPK

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PowerGrasp: Development Aspects for Arm Support Systems

2022 , Goppold, J.-P. , Kuschan, J. , Schmidt, H. , Krüger, J.

Exoskeletons can support workers on physically demanding tasks, but in industry they lack of acceptance. This contribution gives an insight into design aspects for upper body exoskeletons, especially how active exoskeletons for industrial applications differ from military and medical use-cases. To overcome typical rigid exoskeleton problems, we suggest the use of modular soft-exosuit support systems and therefore checked different types of soft actuation principles for their eligibility for the use on upper body joints. Most promising approach is using two-layered actuators sting of robust fabric with embedded rubber tubes as pressure chambers. By inflating the tubes, it is possible to vary the stiffness of the chambers, which can be effectively used to generate assisting forces and moments at human joints (shoulder, elbow, wrist, finger).

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Development of a Conceptual Understanding of the term Technological Capability

2021 , Hecklau, Fabian , Kidschun, Florian , Kohl, Holger , Hizal, Gamze Gül

The term "technological capability" has been studied for almost 40 years. It is an important component of technology strategy that contributes to the success and strengthening of organizations competitiveness. There are numerous attempts to define the term in the literature, but it is always used in different contexts. Thus, the definition of technological capability varies depending on the researcher's perspective and objectives. Therefore, the main objective of this research is to develop an own definition and interpretation of the term technological capability. To this end, an extensive literature review will be conducted to examine the basic concepts and management areas of technological capability and to analyze the individual definitions of the term. The subsequent goal is to derive an understanding of what technological capability is in terms of research and technology organizations.

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Micro-milling of a sprue structure in tungsten carbide-based metal matrix composite

2021 , Uhlmann, E. , Polte, J. , Polte, M. , Hein, C. , Hocke, T. , Jahnke, C.

Many industries rely on plastic components manufactured by micro-injection moulding. There is a high potential to further increase the cost-effectiveness by machining the moulds needed for this process from non-ferrous metals and reinforcing the parts of the mould, which experience high loads during the micro-injection moulding. Inserting tungsten carbide particles locally into the surface of these non-ferrous metals is one possibility of reinforcement. The resulting metal-matrix-composites (MMC) exhibit the needed wear resistance, while the ground material can be machined very effectively through micro-milling. In contrast, the Micro-milling of these MMC-materials is challenging and so far not state of the art. Thus, this investigation is concerned with the development and qualification of micro-milling parameters for tungsten carbide-based MMC-materials. Binderless polycrystalline diamond as innovative cutting material was applied for this purpose. The goal of the mil ling parameter development was to optimize the surface roughness and the form accuracy for machining an aluminium bronze workpiece reinforced with tungsten carbide particles through laser injection. Based on an analysis of a wide range of process parameters, an optimised milling strategy was applied to machine a sprue structure from the described MMC-material. Different parameter sets are evaluated by analysing the form accuracy and measuring the surface roughness of machined structures. A surface roughness of Ra = 80 nm and form accuracy of a = 3 µm could be achieved with optimized micro-milling parameters and qualified the developed parameters for industrial applications.

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Towards a Framework for Impact Assessment of Research & Technology Organisations

2021 , Kidschun, Florian , Hecklau, Fabian

Due to their ability to bridge the gap between knowledge created by basic research and market requirements, Research and Technology Organisations (RTOs) play a major role in countriesâ innovation systems. Their R&D results should lead to innovations, which in turn generate the economic output of public investment in research and development. Moreover, they should support the foundation of new companies and industrial innovations. RTOs can thus be seen as intermediaries between R&D and the industry, while they themselves constitute to a certain extent entrepreneurs and actors in applied R&D that focus on industrial and commercial application right from the start of their activities. Therewith, RTOs pursue to increase the competitiveness of the entire economy. With a growing demand for evaluating their actual contribution in national innovation systems, simply stating the goal of positive impact to stakeholders like governments, the public, investors etc. is not enough; its accomplishment needs to be proven by robust evidence. In this regard, the value of an impact assessment is determined by the strength of the evidence produced and the credibility of the evaluation. RTOâs research activities and their impacts are diverse in nature and occur across many sectors of the economy. To gain transparent insights into relevant and comprehensive performance metrics showing the impact of RTOs from a micro- and macroeconomic perspective, impacts are only appropriate for evaluation if a causal relationship can be drawn back to their origin. While some impacts are primarily economic and suitable for quantitative analysis, others have to be evaluated qualitatively. Regardless of its type, each impact needs to be assessed within a common framework to enable a comprehensive understanding of RTO's impact. Within this contribution, an impact assessment framework is established with the aim to enable the identification of causal relationships between impacts and their origin.

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Service Modelling Language Applied for Hyper Connected Ecosystem

2021 , Jäkel, Frank-Walter , Zelm, Martin , Chen, David

The paper elaborates the application of service modelling language for hyper-connected ecosystems. A specific target is to demonstrate the use of ISO 19440 standard together with a set of specialized service modelling constructs developed in the scope of CEN TC310/WG1. It presents a conceptual use case to model a 'Matching Service' and the service system required to provide the Matching Service in a service ecosystem. The purpose of this study is to test and demonstrate the use of a service modelling language related to ISO19440:2020 to describe in a formal and systematic way a service and its needed service system at business level for communication and validation. The paper first presents the motivation of the study and recalls related works. The service modelling language and the background of this work are discussed. The Matching service use case will be presented in detail and the concluding summary as well as some outlooks are given at the end of the paper.

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Tool wear and surface roughness in micro-milling of aluminium and high-alloyed aluminium materials using cutting tools made of binderless carbide

2021 , Uhlmann, E. , Polte, M. , Hein, C. , Polte, J. , Wiesner, H.M.

Micro-milling can be applied for manufacturing in a wide range of materials and complex geometries. This process is especially important for the aerospace industry. High-alloyed aluminium is a common material for aerospace applications with complex micro- and macro-geometry due to its high wear resistance. The costs-effectiveness of producing these parts can be increased by using tools with improved wear behaviour and higher life times. However, wear-resistant tools are often associated with higher tool costs, which reduces the cost-effectivness of the whole production. An innovative solution is offered by the use of a cutting tool made of binderless tungsten carbide. The micro-milling of conventional and high-alloy aluminium with a new cutting material based on a binderless tungsten carbide is analysed in this investigation. The absence of a binding phase leads to an increased hardness and improves the wear behaviour of these tools. Therefore, tools with a tool diamete r of D = 10 mm were manufactured and there machinability was successfully proven. The feasibility of these innovative tools is demonstrated in a series of experiments. The experimental investigations were carried out on the five-axis high precision machine tool PFM 4024-5D PRIMACON GMBH, PeiÃenberg, Germany, with a workpiece made of TiAl 48-2-2. A surface roughness of Ra = 0.202 µm was detected after a path length due to primary motion lc = 70 m without any noticeable wear marks on the cutting tool. These results show the economic potential for milling tools based on binderless carbide for achieving high precision surfaces while reaching high lifetimes.

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Investigation on laser cladding of rail steel without preheating

2021 , Brunner-Schwer, Christian , Biegler, Max , Rethmeier, Michael

The contact between train wheels and rail tracks is known to induce material degradation in the form of wear, and rolling contact fatigue in the railhead. Rails with a pearlitic microstructure have proven to provide the best wear resistance under severe wheel-rail interaction in heavy haul applications. High speed laser cladding, a state-of-the-art surface engineering technique, is a promising solution to repair damaged railheads. However, without appropriate preheating or processing strategies, the utilized steel grades lead to martensite formation and cracking during deposition welding. In this study, laser cladding of low-alloy steel at very high speeds was investigated, without preheating the railheads. Process speeds of up to 27 m/min and laser power of 2 kW are used. The clad, heat affected zone and base material are examined for cracks and martensite formation by hardness tests and metallographic inspections. A methodology for process optimization is presented and the specimens are characterized for suitability. Within the resulting narrow HAZ, the hardness could be significantly reduced.

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Sensor integration in hybrid additive manufactured parts for real-time monitoring in turbine operations

2021 , Uhlmann, E. , Polte, J. , Kersting, R. , Brunner-Schwer, C. , Neuwald, T.

Real-time monitoring of operation conditions such as tempeatures and vibrations enables efficiency enhancement for maintenance tasks. In energy industry monitoring of critical components such as turbine blades is essential for the operation safety. But the effective recording of critical process data is a challenging task due to the extreme operating conditions. With a hybrid processing approach combining two additive manufacturing technologies new classes of self-monitoring components become possible allowing data acquisition directly inside the component. Using the example of a turbine blade, the hybrid process chain is described. The turbine blade blank is produced via Laser Powder Bed Fusion (L-PBF) with channels for the integration of high temperature sensors. After integration cavities were closed by Laser Directed Energy Deposition (L-DED) followed by classical milling operations for part finishing. The data acquisition is integrated in state-of-the-art product l ifecycle monitoring (PLM) software to create a digital twin. Evaluation shows that temperature could be successfully monitored at conditions of Π= 550°C.

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Precision finishing of additively manufactured components using the immersed tumbling process

2021 , Polte, J. , Polte, M. , Hocke, T. , Lahoda, C. , Uhlmann, E.

Additive manufacturing enables the production of highly complex metallic components with highest geometrical flexibility in dedicated lightweight construction. For titanium-aluminium alloys, which are used in particular in the aviation industry, powder bed based processes such as the laser powder bed fusion are established. Nevertheless, laser powder bed fusion is limited with regard to the producible surface roughness in a range of 5 µm ⤠Ra ⤠15 µm. According to the state of the art, the increase of the geometrical accuracy and the reduction of the surface roughness values of the additive manufactured components are realised by different cutting and non-conventional processes. In this investigation, a new approach for the reduction of the surface roughness values by immersed tumbling was realised. Therefore, additively manufactured square bars made of the titanium alloy Ti-5Al-5Mo-5V-3Cr were used as sample geometries. An immersed tumbling machine tool with plan etary kinematics for post-processing was applied and the lapping media QZ, HSC 1/500 and M5/400 were evaluated. In addition, the influence of the rotor speed and the holder as well as the depth of immersion were considered as influencing factors. As target values the surface roughness values as well as the rounded edge radius were examined. Within this investigations the surface roughness values could be reduced by more than 90 %. In addition, a targeted rounding of the edges could be obtained, which removed the excess edge height at the part resulting from the laser powder bed fusion process. As a result the immersed tumbling process shows a great suitability as a finishing process for additively manufactured components and is particularly suitable for automated and serial finishing processes.

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Time-Sensitive Networking over Metropolitan Area Networks for Remote Industrial Control

2021 , Tschöke, Simon , Lynker, Frederic , Buhr, Hauke , Schreiner, Florian , Willner, Alexander , Vick, Axel , Chemnitz, Moritz

The benefits of the currently evolving IEEE Time-Sensitive Networking (TSN) standard have already been globally recognized. Whereas the application of TSN in a LAN is currently widely and globally tested, TSN in a Metropolitan Area Network (MAN) has not been a major focus until now. The possible benefits of utilizing co-located Edge Clouds in order to support multiple urban production sites with industrial realtime applications open a wide range of new business models. Therefore, we have analyzed the feasibility of transparently using PROFINET over TSN via a Dense Wavelength Division Multiplex (DWDM) link, where a machine park is controlled remotely by an Edge-based virtual Programmable Logic Controller (vPLC). As a result, we are able to setup a TSN connection over a MAN with a one-way delay of about 156.5 J.ms and a jitter of about 12 ns. This work can be extended to allow for dynamically provisioned TSN flows and multi-path Frame Replication and Elimination (FRER) for distributed hard real-time machine control and adoption to Ultra-Reliable Low-Latency Communication (URLLC) 5G campus networks.

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