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89th Annual Meeting on the International Association of Applied Mathematics and Mechanics, GAMM 2018

作者： Glänzel, Janine Stoll, Martin Unger, Roman Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Straße 88 Chemnitz09126 Germany Technische Universität Chemnitz Faculty of Mathematics Reichenhainer Straße 41 Chemnitz09126 Germany

Thermo-elastic deformations represent one of the main reasons for positioning errors in machine tools. Investigations of the thermo-mechanical behaviour of machine tools often rely on accurate simulations involving large-scale CFD simulations, where the heat transfer coefficient is computed. It has been shown that radial basis functions (RBFs) are a valid tool to reduce the number of CFD simulations by interpolation. We here present an efficient approach for the case of a three-axis milling machine. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

关键词： machine tools

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High Precision Machining of Hybrid Layer Composites by Abrasive Waterjet Cutting

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Procedia Manufacturing 2018年 21卷 583-590页

作者： M. Putz A. Rennau M. Dix Chemnitz University of Technology Institute for Machine Tools and Production Processes (IWP) Reichenhainer Str. 70 09126 Chemnitz Germany Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Str. 88 09126 Chemnitz Germany

In industrial applications the increasing variety of high performance materials and their combination to material composites is challenging for the common machining processes. Their high application range combined with minimal forces and no significant thermal loads predestinates abrasive waterjet cutting for machining such complex structures. This paper verifies the high precision machinability of 2D- and 3D-layer composites out of CFRP and a lightweight metal such as aluminum or magnesium using the abrasive waterjet. Therefore, different cutting strategies were determined as well as process influences to the joining zone and characteristics of the machined component.

关键词： Waterjet machining Fiber reinforced plastic Hybrid layer composite

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Methodology for the early analysis and evaluation of the resource efficiency of process chains for manufacturing hybrid structures

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Procedia Manufacturing 2019年 33卷 430-437页

作者： C. Symmank J. Boll A. Rautenstrauch A. Graf L. Markov R. Decker A. Schmidt U. Götze B. Awiszus V. Kräusel D. Landgrebe L. Kroll Professorship of Management Accounting and Control Chemnitz University of Technology Thüringer Weg 7 09126 Chemnitz Germany Professorship Virtual Production Engineering Chemnitz University of Technology Reichenhainer Straße 70 09126 Chemnitz Germany Professorship for Forming and Joining Chemnitz University of Technology Reichenhainer Straße 70 09126 Chemnitz Germany Department of Lightweight Structures and Polymer Technology Chemnitz University of Technology Reichenhainer Straße 31/33 09126 Chemnitz Germany Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Straße 88 09126 Chemnitz Germany

To ensure a successful development of resource-efficient and sustainable technologies, products, and production processes, it is essential to support R&D activities in early design stages. Thus, amongst others an appropriate assessment should be accomplished, which captures the high complexity and interdependencies of process chains, considers the technological feasibility, the energetic and economic benefit as well as the robustness as facets of resource efficiency, and hence, serves as a basis for deriving impulses for R&D activities. A promising evaluation methodology for such assessments is the Multidimensional Evaluation Method for Process Chains of HybrId Structures (MEMPHIS). In this paper, MEMPHIS is outlined and illustrated for an innovative process chain for producing hybrid laminates with sensor functionality. As a result, the paper will contribute to the further development of the methodology, show its applicability, and provide insights into the innovative technology.

关键词： cost effectiveness energy efficiency hybrid assembled composites robustness sustainable manufacturing processes

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Requirements for Volume Flexibility and Changeability in the Production of Electrified Powertrains

Requirements for Volume Flexibility and Changeability in the...

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International Electric Drives Production Conference (EDPC)

作者： Jens Niemann Christoph Eckermann Andreas Schlegel Thomas Büttner Johannes Stoldt Matthias Putz Planning and Production of Electrified Powertrains BMWAG Munich Germany Machine Tools Production Systems and Machining Fraunhofer-Institute for Machine Tools and Forming Technology IWU Chemnitz Germany

ISBN: (纸本)9781728101491;9781728101484

Electro mobility represents a key concept in response to current trends in the mobility sector. Yet, strong uncertainties regarding future demand of electric vehicles pose major challenges for capacity planning and procurement. Current forecasts predict a total market share of electric vehicles between 3 % and 24 % in 2025. This paper presents a study that aims to shed light on the challenges of capacity planning. We provide insights on the requirements of volume flexibility and changeability in the production and purchasing of electrified powertrains. The study relies on expert interviews in the field of production and procurement. We interviewed 13 managers from three leading, premium German carmakers. The interviews were conducted using a semi-structured guide that addresses six hypotheses concerning market development, long-term capacity planning, identification and definition of courses of action, interdependencies between the production and the supplier, specifics of the production system for electrified powertrains, and access to resources. The study's results show that demand volatility of electrified vehicles is expected to persist for the next 5 years. Consequently, existing demand uncertainties lead to a high number of different planning scenarios. This challenges capacity planners to provide enough capacity by relying on flexibility or changeability measures. Differences in supplier structures further require automotive OEM to change their mindset and to implement new processes. Despite those substantial changes, however, the task of purchasing remains vital to prevent quality losses or significant cost increases. Lastly, we show the importance of integrating supplier and purchasing department capacity planning process. Our main results indicate the need for developing a decision support system. It supports supply chain capacity planning of electric drive trains in order to enable fast and efficient reactions to volatile volumes.

关键词： Capacity planning Supply chains Interviews Electric vehicles Mechanical power transmission Uncertainty

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Sensorless fault detection in linear axes with dynamic load profiles

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Procedia Manufacturing 2018年 19卷 66-73页

作者： M. Putz C. Trimborn C. Naumann J. Fischer M. Naumann L. Gebel Fraunhofer-Institute for Machine Tools and Forming Technology IWU Reichenhainer Straße 88 09126 Chemnitz Germany Volkswagen AG Berliner Ring 2 38440 Wolfsburg Germany

Press lines are commonplace in the automotive industry. They typically use transfer systems to transport parts from one manufacturing stage to the next. Since these transfers are forced to endure great loads, both the gears and the shaft break fairly frequently and need to be replaced. Since every minute of downtime these maintenance tasks require costs manufacturers a lot of money, a condition monitoring system able to detect or predict damaged parts in linear drives would allow them to schedule maintenance so that downtime can be minimized and costs reduced. This paper presents a new method of fault detection for dynamic load profiles which is non-intrusive and requires no additional sensors. After a brief overview of the state of the art in fault detection and condition monitoring, the new method will be explained and demonstrated using measurement data from a press transfer.

关键词： Condition monitoring Servo system Motor current signature analysis

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Evaluation of thermo-energetic behavior for demand-oriented operating of machine tool cooling systems

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Procedia Manufacturing 2018年 21卷 213-220页

作者： Joachim Regel Du Xu Michael Bräunig Volker Wittstock Matthias Putz Institute for Machine Tools and Production Processes Technische Universität Chemnitz Reichenhainer Str. 70 09126 Chemnitz Germany Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Str. 88 09126 Chemnitz Germany

In state of the art machine tools, structural thermal displacement is commonly reduced by cooling and tempering measures. The application of these measures frequently counteracts the original goal of energy efficiency. To design demand-oriented cooling systems, this paper presents a method to evaluate cooling measures and control parameters by means of a variance-based sensitivity analysis regarding the thermo-energetic efficiency. The evaluation is carried out by using the example of a machine bed made of high performance concrete. The integrated fluid-air cooling system with fan speed control and the bed structure are modelled by lumped elements. In addition to the PID-control of the cooling fluid temperature, the evaluation considers a two-position control of separately controllable cooling circuits and the influence of ambient temperature. The criteria to evaluate are temperature differences within the machine structure, the dissipated heat and their proportions to deployed electrical energy.

关键词： machine tool sensitivity analysis thermal measures cooling system energy efficiency simulation experiment thermal modeling

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The Effect of Torsional Vibrations on Metal Cutting Dynamics

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Procedia CIRP 2018年 77卷 461-464页

作者： Andreas Otto Martin Kolouch Günter Radons Institute of Physics Chemnitz University of Technology 09107 Chemnitz Germany Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Straße 88 09126 Chemnitz Germany

The effect of torsional vibrations on the dynamics of metal cutting processes is studied. An extended dynamic process model is presented, where the spindle angle and the time delay are dynamic variables resulting in delay differential equations with state-dependent delay. Stability lobes are calculated based on the new extended process model and compared with results from the classical chatter theory with constant spindle speed and delay. For an ideal symmetric tool, stable cutting is characterized by a periodic spindle speed but still a constant delay. In this case, the main difference between the new extended and the classical model is a different periodic solution to periodic torsional tool displacements, which results only in slight modifications of the stability lobes. However, the new theory shows that it is important to consider tool asymmetries (e.g. runout), because this would result in periodically varying delays during stable cutting and larger stability changes due to torsional vibrations.

关键词： Metal Cutting Sawing Chatter Vibrations Stability State-dependent delay

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Using Industrial Robots as Haptic Devices for VR-Training

Using Industrial Robots as Haptic Devices for VR-Training

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IEEE Annual International Symposium Virtual Reality

作者： Sebastian Knopp Mario Lorenz Luigi Pelliccia Philipp Klimant Institute for Machine Tools and Production Processes University of Technology Chemnitz Department of Orthopedics University Clinics of Leipzig Chemnitz Institute for Machine Tools and Production Processes Chemnitz University of Technology Fraunhofer Institute for Machine Tools and Forming Technology IWU Chemnitz

ISBN: (纸本)9781538633663

Many VR-training application require the integration of haptics, i.e. for surgical training. However, surgical VR-training is still limited to minimal invasive surgeries. For surgeries where high forces occur, like hip replacement, no VR-training applications have been developed. One cause for this is the lack of appropriate haptic devices which can deliver high forces. Novel industrial collaborative robots can provide high forces. Although, they lack control interfaces allowing to use them as haptic devices. We present 4 approaches for using these robots as general, multipurpose haptic input and output devices. The implemented approach was integrated into a VR hip replacement training application. An initial assessment demonstrates the general feasibility of our solution.

关键词： Conferences Virtual reality Three-dimensional displays User interfaces

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Equivalence assessment method for the resource efficiency of equipment, technologies and production systems

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Procedia Manufacturing 2018年 21卷 525-532页

作者： A.P. Kuznetsov H.-J. Koriath A.V. Kalyashina T. Langer Moscow State University of Technology “STANKIN” 127055 Moscow Russia Fraunhofer Institute for Machine Tools and Forming Technology IWU 09126 Chemnitz Germany Kazan National Research Technical University Kazan Russia

The paper analyses different assessment methods for the overall equipment effectiveness (OEE), energy efficiency and productivity of equipment and production systems. The proposed model and systematic assessment approach define the total and relative resource efficiency of equipment, technologies and production systems in the form of material, energy and information efficiency. This common resource efficiency assessment method is based on the physical and mathematical equivalence of efficiency indicators including probable events for resource usability. Three typical relations, determining any kind of efficiency, are obtained from those equivalents. Examples for resource efficiency assessment types are energy efficiency, productivity and accuracy. Integrated evaluation indicators for a comparative benchmarking of equipment, technologies and production systems are provided based on the equivalence assessment method and the proposed three typical relations. This method is also applicable to process chains.

关键词： equipment resource efficiency technology production system

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Virtual Prototyping Technologies Enabling Resource-Efficient and Human-Centered Product Development

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Procedia Manufacturing 2018年 21卷 749-756页

作者： C. Allmacher M. Dudczig P. Klimant M. Putz Chemnitz University of Technology Reichenhainer Str. 70 09126 Chemnitz Germany Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Str. 88 09126 Chemnitz Germany

In modern production environments employees work progressively closer together with autonomous robots and vehicles. Besides the technical specifications, the development of these products focuses on the human-machine interaction. Within the federally funded Project FOLLOWme an automated guided vehicle (AGV) for intralogistics that follows and interacts with the user is developed using virtual reality based prototypes. The benefits in comparison to using only physical prototypes are on the one hand specific user feedback regarding ergonomics and trust. On the other hand the validation of navigation and collision avoidance algorithms and optimization of technical parameters is achieved considering complex environmental conditions. This paper focuses on the latter in detail and deals with the optimization of a fuzzy logic controller using the game engine Unity3D to create the required virtual setup. This approach saves valuable time at early project stages and allows the optimization of a larger number of parameters compared to just physical tests. Furthermore it reduces resources like occupied physical infrastructure and improves the comprehension by using virtual reality.

关键词： Resource Efficiency Human Factors Virtual Prototype Automated Guided Vehicle Obstacle Avoidance Fuzzy Logic Controller Unity3D

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