High speed velocity effects in production technology provide a broad range of technological and economic advantages [1, 2]. However, exploiting them necessitates the knowledge of strain rate dependent material behavio...
High speed velocity effects in production technology provide a broad range of technological and economic advantages [1, 2]. However, exploiting them necessitates the knowledge of strain rate dependent material behavior in process modelling. In general, high speed material data characterization features several difficulties and requires sophisticated approaches in order to provide reliable material data. This paper proposes two innovative concepts with electromagnetic and pneumatic drive and an approach for material characterization in terms of strain rate dependent flow curves and parameters of failure or damage models. The test setups have been designed for investigations of strain rates up to 105 s-1. In principle, knowledge about the temporary courses and local distributions of stress and strain in the specimen is essential for identifying material characteristics, but short process times, fast changes of the measurement values, small specimen size and frequently limited accessibility of the specimen during the test hinder directly measuring these parameters at high-velocity testing. Therefore, auxiliary test parameters, which are easier to measure, are recorded and used as input data for an inverse numerical simulation that provides the desired material characteristics, e.g. the Johnson-Cook parameters, as a result. These parameters are a force equivalent strain signal on a measurement body and the displacement of the upper specimen edge.
Boron doped diamond materials, which are generated by Chemical Vapor Deposition (CVD), offer a great potential for the application on highly stressed tools, e. g. in cutting or forming processes. As a result of the CV...
Boron doped diamond materials, which are generated by Chemical Vapor Deposition (CVD), offer a great potential for the application on highly stressed tools, e. g. in cutting or forming processes. As a result of the CVD process rough surfaces arise, which require a finishing treatment in particular for the application in formingtools. Cutting techniques such as milling and grinding are hardly applicable for the finish machining because of the high strength of diamond. Due to its process principle of ablating material by melting and evaporating, Electrical Discharge Machining (EDM) is independent of hardness, brittleness or toughness of the workpiece material. EDM is a suitable technology for machining and structuring CVD diamond, since boron doped CVD diamond is electrically *** this study the ablation characteristics of boron doped CVD diamond by micro electrical discharge machining are investigated. Experiments were carried out to investigate the influence of different process parameters on the machining result. The impact of tool-polarity, voltage and discharge energy on the resulting erosion geometry and the tool wear was analyzed. A variation in path overlapping during the erosion of planar areas leads to different microstructures. The results show that micro EDM is a suitable technology for finishing of boron doped CVD diamond.
Determination of the material behaviour for high speed forming processes is challenging due to high process velocity and small specimen geometry in experimental analysis. This paper proposes two different material cha...
Determination of the material behaviour for high speed forming processes is challenging due to high process velocity and small specimen geometry in experimental analysis. This paper proposes two different material characterisation concepts for high strain rates at 103 s−1 and higher, namely a pneumatically device and an electromagnetically accelerated hammer, for obtaining experimental values. Furthermore, two measuring principles of the hammer velocity and displacement are presented and compared. The authors describe a measurement system with an acceleration sensor for the pneumatic device and a shadowing principle for the electromagnetically driven concept. Using the measured data, material parameters are iteratively adapted in an optimisation procedure until an objective function, comparing the difference between numerical and experimental results, is satisfied. In this case the parameter identification is applied on a strain rate dependant flow curve approximation based on Johnson-Cook.
This paper introduces the application of the Unscented Kalman Filter (UKF) for the support of different error models for machinetools. The UKF is used to minimize measuring and modeling errors for geometric and therm...
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This paper introduces the application of the Unscented Kalman Filter (UKF) for the support of different error models for machinetools. The UKF is used to minimize measuring and modeling errors for geometric and thermal errors of machinetools. Error models are introduced and transformed into a formulation for the UKF. Geometric and thermal error measurements in three- and five-axis machinetools are presented. The modeling and potential correction results with and without the UKF are analyzed and compared. It is observed that the Unscented Kalman Filter is able to reduce modeling errors due to non-linearity and measurement noise.
Condition Monitoring and Maintenance prediction are permanent demands of state-of-the-art machinetools. Their IT-infrastructure including drive control systems and specific sensors deliver extensive amounts of data f...
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Condition Monitoring and Maintenance prediction are permanent demands of state-of-the-art machinetools. Their IT-infrastructure including drive control systems and specific sensors deliver extensive amounts of data for monitoring. However to combine and link this data to define critical characteristic values remains challenging. The paper presents a novel approach to deal with these tasks. Firstly equal machine states are detected at different times by checking and comparing several parameters. If an equal state is detected an algorithm is executed which leads to a characteristic value. The value as well as its limits is self-adapting and time-depending by constant redefining based on the machine history.
Additive manufacturing (AM) processes are based on the controlled selective deposition of material by which a part is manufactured or remanufactured (repaired), layer by layer. Research in AM is drastically on the inc...
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Additive manufacturing (AM) processes are based on the controlled selective deposition of material by which a part is manufactured or remanufactured (repaired), layer by layer. Research in AM is drastically on the increase in the last several years owing to the benefits that AM provides over conventional manufacturing i.e. reduction in material usage, time-to-market reduction, improved functionality, increased ability to customize and near-net shape manufacturing. There has been a number of AM techniques focused on non-metallic materials. In addition, many industries have already embraced the use of AM for metallic parts using laser as an efficient machining tool, including automotive, die & mold, aerospace & defense, industrial products, consumer products and health care. However, the research on metallic materials has been facing a lot of obstacles due to the complexity involved in laser additive manufacturing (LAM) process. This complexity arrives from a multitude variables involved in the process itself i.e. system design as well as process design variables. As a result, there are nowadays limited AM technologies commercially available. This can motivate researchers to focus their work in order to ruggedize LAM processes for commercial large-scale. In this regard, this paper gives the definition and classification of additive manufacturing processes according to ASTM Standard F2792-12a, followed by a description of principles and future perspectives for fabrication of parts via LAM focused on hot-work tool steels, and potential future applications of LAM for industries i.e. die & mold, forging and cutting tools and automotive. The present paper also talks about the barriers to implementation of LAM for hot-work tool steels.
The global trends towards improving fuel efficiency and reducing CO;emissions are the key drivers for lightweight solutions. In sheet metal processing, this can be achieved by the use of materials with a supreme stren...
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The global trends towards improving fuel efficiency and reducing CO;emissions are the key drivers for lightweight solutions. In sheet metal processing, this can be achieved by the use of materials with a supreme strength-toweight and stiffness-to-weight ratio. Besides monolithic materials such as high-strength or light metals, in particular metal–plastic composite sheets are able to provide outstanding mechanical properties. Thus, the adaption of conventional, wellestablished forming methods for the processing of hybrid sheet metals is a current challenge for the sheet metal working industry. In this work, the planning phase for a conventional sheet metal forming process is studied aiming at the forming of metal–plastic composite sheets. The single process steps like material characterization, FE analysis, tool design and development of robust process parameters are studied in detail and adapted to the specific properties of metal–plastic composites. In material characterization, the model of the hybrid laminate needs to represent not only the mechanical properties of the individual combined materials, but also needs to reflect the behaviour of the interface zone between *** on experience, there is a strong dependency on temperature as well as strain rate. While monolithic materials show a moderate anisotropic behaviour, loads on laminates in different directions generate different strain states and completely different failure modes. During the FE analysis, thermo-mechanic and thermo-dynamic effects influence the temperature distribution within tool and work pieces and subsequently the forming behaviour. During try out and production phase,those additional influencing factors are limiting the process window even more and therefore need to be considered for the design of a robust forming process. A roadmap for sheet metal forming adjusted to metal–plastic composites is presented in this paper.
Modern value creation is characterized by collaboration of large networks of specialized companies. Due to market requirements and increasing competition, concurrent or simultaneous engineering has become the standard...
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Additive Manufacturing (AM) provides an industrially relevant technology for serial production of complex parts. A layer-wise buildup permits an innovative product design, for instance via functional integration, ligh...
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Additive Manufacturing (AM) provides an industrially relevant technology for serial production of complex parts. A layer-wise buildup permits an innovative product design, for instance via functional integration, lightweight design following biomimetic principles. This results in a vast design solution space for product optimization. Exhausting the potential of AM relies on a systematic and economic design phase. The wide range of the design solution space prevents an economic exploitation of design freedom and results in an incomplete part optimization. This leads to an unsystematic design, a cost-intensive and long term trial-and-error part design optimization. This paper presents a systematic design approach. A situative application- and target-oriented TRIZ-based methodology is introduced that incorporates database-enhanced biomimetic part design specifically for AM. Inspired by nature those examples provide a vast design solution space due to an extensive evolutionary development of various optimized systems. The work is concluded with a validation through a case study of a design optimization problem.
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