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10th International Conference on technology of Plasticity, ICTP 2011

作者： Neugebauer, R. Göschel, A. Rautenstrauch, A. Meza-García, E. Fraunhofer Institute for Machine Tools and Forming Technology IWU Chemnitz Germany Machine Tools and Forming Technology TU Chemnitz Germany

ISBN: (纸本)9783514007840

Continuous Cooling Transformation (CCT) diagrams determined with a dilatometer were used to analyse the influence of the alloying elements on the phase transitions of high strength steel sheet alloys. Mo and Cr additions showed a significant influence on the extension of the bainitic region, whereas C and B additions showed noteworthy Improvement on the quenchability of these steel alloys. These alloy properties are desirable requirements to be integrated In the hot formed components. Dilatometer samples of the 22MnB5 steel alloy were used to determine the resulting mechanical properties In function of the cooling rate. Hardness and micro-bending tests were carried out and they showed a qualitative trend with the cooling rate, which permits a preliminary estimation of the crash performance. A hot-forming process of a car B-pillar foot was simulated In commercial finite element code LS-DYNA considering experimentally determined Input parameter for the 22MnB5 sheet alloy. These results were evaluated with an experimental trial showing a good approach. Results obtained In this work show an overview of essential research fields for the optimization of the hot forming process for the production of graded components, Including the possibility of Increasing the spectrum of alloys used In this process. © 2011 Wiley-VCH Verlag GmbH & Co. KGaA. Weinheim.

关键词： High strength steel

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Machining with redundant kinematics

Machining with redundant kinematics

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ASME 2011 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, IDETC/CIE 2011

作者： Neugebauer, Reimund Drossel, Welf-Guntram Ihlenfeldt, Steffen Rentzsch, Hendrik Fraunhofer Institute for Machine Tools and Forming Technology IWU Chemnitz 09126 Germany

ISBN: (纸本)9780791854839

The demand for high productivity and quality combined with the need for decreasing energy consumption will substantially affect machine tool design in the future. This development is driven by a modification of process chains which is focused on resource conservation. One important contribution for that purpose is the transition towards complete machining. This approach calls for a configuration targeting major process stability as well as a structure geared towards accuracy and dynamism. The compromise between potential dynamism and machine size can be improved by using redundant drives. This paper describes models, simulation tools and the method of the development process for redundant kinematics. To highlight the different aspects of designing such machine tool structures, their development process is demonstrated on the basis of two examples, complete machining for tool- and die making and an adaptive spindle holder for micro contouring and -structuring. Copyright © 2011 by ASME.

关键词： Energy utilization

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Semantic Web based dynamic energy analysis and forecasts in manufacturing engineering

Semantic Web based dynamic energy analysis and forecasts in ...

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作者： Wenzel, Ken Riegel, Jörg Schlegel, Andreas Putz, Matthias Fraunhofer Institute for Machine Tools and Forming Technology IWU Chemnitz Germany

ISBN: (纸本)9783642196911

This paper proposes an approach for supporting the analysis of collected energy consumption data in combination with structured system models to reveal correlations between energy usage and related properties of products, operations and equipment. The described method serves as a starting point for the creation of tailored simulation models for energy consumption forecasts that can be used in the planning phase of manufacturing systems. Therefore several energy-oriented simulation methods are introduced and discussed regarding their suitability for different use cases in manufacturing engineering.

关键词： Energy efficiency

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Property distribution in aluminium material processed by gradation rolling

Property distribution in aluminium material processed by gra...

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10th International Conference on technology of Plasticity, ICTP 2011

作者： Neugebauer, R. Sterzing, A. Zachäus, R. Bergmann, M. Fraunhofer Institute for Machine Tools and Forming Technology IWU Chemnitz Germany Chemnitz University of Technology Institute for Machine Tools and Production Processes Germany

ISBN: (纸本)9783514007840

One approach in the area of material development Is the designing of materials properties by grain refinement. Methods of severe plastic deformation (SPD) can create ultrafine-grained or nanostructured metallic materials with outstanding properties. The material Is usually uniformly modified over the complete volume. The paper presents an innovative technological solution for efficient manufacturing of rod shaped specimen with locally different grain sizes. The resulting material properties In different regions of a graded aluminium billet are analyzed by hardness measuring and tension tests. The mechanical properties of processed standard aluminium specimen are Investigated. A method for the investigation of the properties In different layers with tensile tests Is presented. The mechanical parameters show the typical characteristics of coarse grained material in the core region, strain hardened material In the transition region and severely deformed material In the kneaded region of the specimen's outer layers. © 2011 Wiley-VCH Verlag GmbH & Co. KGaA. Weinheim.

关键词： Aluminum

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Structuring of tribological active surfaces for reduction of frictional losses 11

Structuring of tribological active surfaces for reduction of...

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11th International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2011

作者： Schubert, A. Edelmann, J. Sylla, D. Hackert-Oschätzchen, M. Fraunhofer Institute for Machine Tools and Forming Technology IWU Chemnitz Germany Department of Micromanufacturing Technology Chemnitz University of Technology Chemnitz Germany

ISBN: (纸本)9780955308291

Surfaces in a wide range of engineering applications are subject to tribological loads. Many of these surfaces have a profound effect on the efficiency of manufacturing processes and products during service. This paper focuses on the effect of surface microstructure geometry on the friction coefficient between lubricated sliding partners. Initially, the Computational Fluid Dynamics (CFD) package COMSOL Multiphysics was used to determine the effect of geometry parameters of semi-spherical cavities on hydrodynamic pressure. The simulations showed that surface microstructures act as micro pressure chambers that would allow the sliding partners to reach hydrodynamic lubrication at lower operating speeds. Patterns of the microstructure that showed the highest pressure build-up in the simulations were then manufactured by Jet-ECM and tested in a tribometer. It was determined that patterned spherical segment cavities 10 μm deep and 500 μm wide yield a friction coefficient reduction of up to 35 %.

关键词： Multiphysics

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Integrated piezoelectric actuators in deep drawing tools to reduce the try-out

Integrated piezoelectric actuators in deep drawing tools to ...

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10th International Conference on technology of Plasticity, ICTP 2011

作者： Mainda, P. Kerschner, M. Hein, C. Drossel, W.-G. Fraunhofer Institute for Machine Tools and Forming Technology IWU Chemnitz Germany Volkswagen AG Wolfsburg Germany Audi AG Ingolstadt Germany

ISBN: (纸本)9783514007840

Tool making is a very time consuming and expensive operation because many iteration loops are used to manually adjust tool components during the try-out process. That means that trying out deep drawing tools is 30% of the total costs. This is the reason why an active deep drawing tool in kind of an active die was developed at the fraunhofer Institute for machine tools and forming technology iwu in cooperation with Audi and Volkswagen to reduce the costs of the try-out. The main difference between the active and conventional deep drawing tools is using piezoelectric actuators at the active die to control the forming process. The active die idea, which is the main subject of this research, will be presented as well as the findings of experiments with the experimental tool. This experimental tool was designed according to production requirements and has been equipped with piezoelectric actuators at the die that allow active pressure distribution on the sheet metal flange. © 2011 IBF (RWTH Aachen) & IUL (TU Dortmund).

关键词： Deep drawing

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Cast iron cutting with nano TiN and multilayer TiN-CrN coated inserts

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IOP Conference Series: Materials Science and Engineering 2012年第1期40卷

作者： M Perucca S Durante U Semmler C Rüger G G Fuentes E Almandoz DIAD Buttigliera Alta Italy IWU Fraunhofer-Institute for Machine Tools and Forming Technology Chemnitz Germany Center of Advanced Surface Engineering AIN Spain

During the past decade great success has been achieved in the development of duplex and multilayer multi-functional surface systems. Among these surface systems outstanding properties have nanoscale multilayer coatings. Within the framework of the M3-2S project funded in the 7th European Framework Programme, several nanoscale multilayer coatings have been developed and investigated for experimental and industrial validation. This paper shows the performance of TiN and TiN/CrN nanoscale multilayer coatings on WC cutting inserts when machining GJL250 cast iron. The thin films have been deposited by cathodic arc evaporation in an industrial PVD system. The multilayer deposition characteristic and its properties are shown. The inserts have been investigated in systematic cutting experiments of cast iron bars on a turning machine specifically equipped for force measurements, accompanied by wear determination. Furthermore, equivalent experiments have been carried out on an industrial turning unit. Industrial validation criteria have been applied to assess the comparative performance of the coatings. The choice of the material and the machined parts is driven by an interest in automotive applications. The industrial tests show the need to further optimise the multi-scale modelling approach in order to reduce the lead time of the coating development as well as to improve simulation reliability.

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Mechanical joining with self piercing solid‐rivets at elevated tool velocities

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AIP Conference Proceedings 2011年第1期1353卷 1278-1283页

作者： R. Neugebauer F. Jesche C. Kraus S. Hensel Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Straße 88 09126 Chemnitz Germany

In the present paper the influence of a higher setting velocity in the joining process of self piercing solid‐rivets is shown. In the conventional process tool velocities well below 1 m/s are common. The present research results show the potential of increasing them in the range of about 5 m/s. The results are especially relevant for joining high‐strength steels. These steel sheets often cause problems in the process of riveting mixed materials, e. g. aluminium‐steel compound. The high strength of the steel sometimes leads to undesirable material flow in the joining process or unwanted burr development. These effects, which are described in detail in the article, can be reduced significantly for the investigated cases by the use of higher tool velocities. Using a high speed camera and a load cell, a test setup based on a drop tower was realized. It was used to time the force signals and the motion profile of the high speed riveting process. The results of the force analysis show an oscillating force progression. Within a numerical research the principal effects influencing the results of the riveting process can be shown. It was found that the pulse‐like force transmission between riveting machine and punch, results in various vibrations especially of long and thin tool parts. Hence the rivet penetrates the sheet metal with non‐uniform velocities. As a result the early indentation of die into the lower sheet metal at the beginning of the process is reduced, so that the final process step provides a sufficient material flow into the circular rivet groove. A strain‐rate dependent process model with elastic tool properties and consideration of inertia effects is presented.

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Media -Based Press-Hardening of Hollow Profiles

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ATZproduktion worldwide eMagazine 2011年第3期4卷 44-48页

作者： Albert, André Paul, Alexander Pierschel, Norbert Demuth, Rico Fraunhofer Institute for Machine Tools and Forming Technology (IWU) Chemnitz Germany Chemnitz University of Technology Chemnitz Germany

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Micro - EDM: Process effects on the tool wear ratio 11

Micro - EDM: Process effects on the tool wear ratio

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11th International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2011

作者： Schubert, A. Wolf, N. Zeidler, H. Fraunhofer Institute for Machine Tools and Forming Technology IWU Department Micro- and High-Precision Manufacturing Reichenhainer Str. 88 Chemnitz09126 Germany Chemnitz University of Technology Department Micromanufacturing Technology Chemnitz09107 Germany

ISBN: (纸本)9780955308291

The fabrication of high aspect ratio microstructures is very challenging, especially when the work piece material is hard to machine. Electro Discharge Machining (EDM) offers a contact- and nearly force free way of micromachining and is therefore an appropriate means to producing microstructures. One key obstacle for a precise machining by micro-EDM is the tool wear. When ED-machining microstructures process speed, stability and thus tool wear are related to the aspect ratio of the structures. In this study, tool wear ratio within different stages of the EDM process is analysed when machining high aspect ratio micro bores in steel. Experiments with bores of different depths show the correlation between the stage of the process and the flushing conditions on the one hand and the tool wear ratio on the other hand. Thus, it is possible to find and apply optimized parameters for the different process stages. A better understanding of the tool wear will help to minimize it, reducing the cost of the tools and enhancing the precision of the process. This also shall allow an enhancement of the process speed because the need for flushing material out of the bore is reduced by the amount of tool material that can be saved.

关键词： Micromachining

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