检索结果-内蒙古大学图书馆

Resource and Energy Efficiency in Machining Using High-Performance and Hybrid Processes

Procedia CIRP 2012年 1卷 3-16页

作者： R. Neugebauer W. Drossel R. Wertheim C. Hochmuth M. Dix Fraunhofer Institute for Machine Tools and Forming Technology Reichenhainer Str. 88 09126 Chemnitz Germany Institute for Machine Tools and Production Processes Chemnitz University of Technology 09107 Chemnitz Germany

The main goal in manufacturing is to minimize production time, cost, energy and resources while maintaining or even improving performance. The main influence on process efficiency in metal cutting can be related to the machining parameters, while performance also depends on the material behavior such as strain rate, machining temperature and cutting forces. In the past, industry was searching for higher efficiency mainly by using higher production rates, achieved with higher cutting conditions. However, during the last decade the production process chain has been controlled more and more by the near-net-shape of semi-finished components and the use of high performance processes. This paper presents established and new applications of process modifications, substitutions, optimizations as well as the use of hybrid processes. In high performance cutting (HPC) additional elements play an important role, for example tool design and tool material, wear and tool life, coolant strategies, including dry cutting, MQL, cryogenic and high pressure flushing as well as the machine tool properties. Furthermore, this paper presents and discusses examples of the influence of process parameters in turning, milling, drilling, grinding and impact cutting under HPC conditions on the energy and resources efficiency in the automotive, aerospace, dies and moulds, micromachining and heavy duty industries.

关键词： Flushing Hybrid Resources Energy Efficiency

来源：评论

学校读者我要写书评

暂无评论

Thermal Interactions between the Process and Workpiece

引用

Procedia CIRP 2012年 4卷 63-66页

作者： Reimund Neugebauer Welf-Guntram Drossel Steffen Ihlenfeldt Carsten Richter Fraunhofer Institute for Machine Tools and Forming Technology (IWU) Reichenhainer Straße 88 Chemnitz 09126 Germany

According to an international status report, up to 70% of the errors in cutting production can be traced back to time- and process- dependant temperature fluctuations. In particular, thermal effects from processing lead to the deformation of machine components. This affects the tool and the workpiece. This paper considers the research into interactions between process-related and thermal deformations with a focus on the high-precision machining of large workpieces. Previously conducted investigations have demon- strated the effects of the heat flow into the structures of workpieces during the machining process. As one might expect, deforma- tion occurs, which leads to deviations in shape and position. In the same way, length changes due to process-heat transfer can be observed on the tool side. This leads to displacements of the centre point of the tool, which are dependent on the tool geometry and process parameters. However, resulting production errors can often be reduced by improved process control. Considering an exam- ple from the field of mould construction, this problem has been discussed from a practical perspective. Starting with experimental analyses, the heat flow into the workpiece related to the inherent deformation was measured. This was realised using thermographic systems and displacement sensors. Relevant parameters that have a significant influence on the process were to be identified in these tests. Heat-transfer effects were analysed while varying these parameters. In the same way, this should provide support for simulative analyses and facilitate the verification of these analyses. Using computer models, it was possible to detect and evaluate thermoelastic displacements before the processing. Based on this, the findings led to appropriate countermeasures, such as the use of a modified machining sequence. The aim of all of these investigations is the development of optimal machining strategies t o help reduce manufacturing errors.

关键词： Process Thermal effects Machining

来源：评论

学校读者我要写书评

暂无评论

Realistic machine Simulation with Virtual Reality

引用

Procedia CIRP 2012年 3卷 103-108页

作者： R. Neugebauer P. Klimant M. Witt Institute for Machine Tools and Production Processes Chemnitz University of Technology Reichenhainer Strasse 70 09126 Chemnitz Germany Fraunhofer Institute for Machine Tools and Forming Technology Chemnitz Reichenhainer Strasse 88 09126 Chemnitz Germany

Today highly complex components are manufactured on NC-controlled machine tools. The NC programs, controlling these machines, are usually automatically generated by CAM software. This automatic processing is often erroneous. The VR-based realistic machine simulation, presented in this paper, extends the usual content of a machine simulation, like material removal and collision detection, by various new aspects. The coupling of a real NC unit allows the recognition and elimination of all process- as well as controller-caused errors. The integration of the multi-body simulation enables the consideration of inertia, machine rigidity and milling cutter deflection.

关键词： machine Simulation Multi-Body Simulation Virtual Reality

来源：评论

学校读者我要写书评

暂无评论

Ultrasonic-assisted micro-EDM of deep bores: Process and discharge analysis 12

Ultrasonic-assisted micro-EDM of deep bores: Process and dis...

引用

12th International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2012

作者： Schubert, Andreas Zeidler, Henning Wolf, Nicolas Hackert-Oschätzchen, Matthias Schneider, Jörg Chemnitz University of Technology Department of Micromanufacturing Technology Reichenhainer Str. 70 Chemnitz09107 Germany Fraunhofer Institute for Machine Tools and Forming Technology IWU Department Micro- and High-Precision Manufacturing Reichenhainer Str. 88 Chemnitz09126 Germany

ISBN: (纸本)9780956679000

Ultrasonic vibration has been found very beneficial for the micro electro discharge machining (μEDM) of deep microstructures with high aspect ratios. In this study, the discharge properties of μEDM aided with direct ultrasonic workpiece vibration are analysed and compared to conventional μEDM machining. It can be shown that not only the number of discharges per second is significantly improved, but also the typical height of the discharge current is differently distributed. The investigation shows that the amount of open circuit states in μEDM can be noticeably reduced by using ultrasonic vibration assistance.

关键词： Ultrasonic effects

来源：评论

学校读者我要写书评

暂无评论

SIMULATION AND OPTIMIZATION OF ROBOT DRIVEN PRODUCTION SYSTEMS FOR PEAK-LOAD REDUCTION 12

SIMULATION AND OPTIMIZATION OF ROBOT DRIVEN PRODUCTION SYSTE...

引用

Simulation Conference

作者： Soren Lorenz Matthias Hesse Anja Fischer Fraunhofer Institute for Machine Tools and Forming Technology IWU Chemnitz Germany Chemnitz University of Technology Chemnitz Germany

ISBN: (纸本)9781467347792

One way to improve the energy efficiency in manufacturing is the use of energy-sensitive methods in production planning. So far, the energy consumption behavior of production facilities has not been investigated in great detail. Estimates are typically obtained by connected wattage values and concurrency factors. We present a new methodology to simulate and optimize complex robot driven production systems with special emphasis on energy aspects. In particular, we show how to translate the process descriptions and energy consumption profiles into a discrete-event-based simulation model and illustrate this with an example of a car body shop facility. In order to minimize the peak-load we set up an optimization model that is based on periodic time-expanded networks. A solution of this model corresponds to a process sequence for the robots that prescribes relative starting times via additional wait intervals. This sequence is then reinserted into the simulation model to validate the improvement.

关键词： improvement sequence simulation

来源：评论

学校读者我要写书评

暂无评论

Model-based position control of Shape memory alloy actuators

引用

International Journal of Mechatronics and Manufacturing Systems 2012年第2期5卷 93-105页

作者： Neugebauer, Reimund Pagel, Kenny Bucht, Andre Drossel, Welf-Guntram Department of Adaptronics and Acoustics Fraunhofer Institute for Machine Tools and Forming Technology Nöthnitzer Straße 44 01187 Dresden Germany

Shape-memory-alloys (SMAs) are easy to integrate into mechanical structures and capable of handling high specific workloads. Therefore, SMAs possess an outstanding potential to serve as positioning devices in various applications. We present here the multi-domain modelling of an electrically heated SMA wire which includes changes of electrical parameters in conjunction to mechanical parameters. Due to the correlation between electrical resistance and mechanical stroke, it was possible to implement a resistance-based position control without the necessity of an external positioning sensor. In order to design a linear position controller by common rules, the highly complex and non-linear model was simplified. Controller development yielded a PID algorithm that was implemented on a rapid prototyping system as part of an SMA wire test bench. The models accuracy was verified by various measurements with different wires and multiple loads. Based on that, it was possible to design an actuator which utilises a flexible socket instead of fixed mountings. Copyright © 2012 Inderscience Enterprises Ltd.

关键词： Position control

来源：评论

学校读者我要写书评

暂无评论

Automatic Production of Induced Pluripotent Stem Cells

引用

Procedia CIRP 2013年 5卷 2-6页

作者： Ulrich Marx Friedrich Schenk Jan Behrens Ulrike Meyr Paul Wanek Werner Zang Robert Schmitt Oliver Brüstle Martin Zenke Fritz Klocke Fraunhofer Institute for Production Technology IPT Steinbachstr. 17 52074 Aachen Germany Institute for Biomedical Engineering Department of Cell Biology RWTH Aachen University Hospital Pauwelsstr. 30 52074 Aachen Germany FH Aachen Campus Jülich Heinrich-Mußmann-Str. 1 52428 Jülich Germany Laboratory for Machine Tools and Production Engineering WZL RWTH Aachen University 52056 Aachen Germany Institute of Reconstructive Neurobiology University of Bonn Sigmund-Freud-Straße 25 53127 Bonn Germany

Induced pluripotent stem cells (iPS cells) exhibit unique properties similar to embryonic stem cells (ES cells). A central feature of iPS cells is their pluripotency: they have the potential of growing indefinitely and differentiating into all cell types of the human body. Therefore, essentially unlimited numbers of somatic cells might be generated. Until now, there is a paucity of industrial processes for large scale production of human iPS cells and their differentiated progeny. This is mostly due to the high complexity of the manual processes, which are involved in the production of these cells. To take full advantage of the potential of iPS cell technology there is the need to produce iPS cell lines in high numbers, by employing automation, high throughput techniques and standardized protocols. Therefore we set up a large scale research project to develop a novel automatic production unit for reprogramming, cultivation and differentiation of iPS cells. A key step within the process chain is the automatic selection of primary iPS cell colonies in the culture dish. Within this study central elements of the automation process and quality control are presented.

关键词： Induced pluripotent stem cells iPC cells iPSC laboratory automation Measurement technology

来源：评论

学校读者我要写书评

暂无评论

New High-Speed machine Tool Structure by Holistic Mechatronic Systems Design

引用

Procedia CIRP 2012年 1卷 307-312页

作者： R. Neugebauer S. Ihlenfeldt U. Frieß M. Wabner S. Rauh Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Str. 88 09126 Chemnitz Germany Chemnitz University of Technology Reichenhainer Str. 70 09126 Chemnitz Germany

One possibility to increase the performance of machine tools is the achievement of higher accelerations and jerks of moved slides and stands. By this the energy consumption and machining-costs can be optimized. Nowadays machine tool structures are already optimized and further enhancements are not easily achieved. The paper deals with the mechatronic system optimization of a large-scale HSC- and HPC- portal milling centre for e.g. forming tools. This includes the identification of dynamic limiting structures and the following optimization by mechatronic system-monitoring. From process necessities a machining-time reduction by higher accelerations and improved process stability is intended. The system parameters where achieved by the implementation of a redundant axis and the usage of up-to-date lightweight design by reinforced *** over the design phase the structure was constantly monitored regarding their dynamic behaviour. Furthermore a model was used – using a state space – to prejudge the machining time for a concrete example cycle. So even before any physical prototype exists the mechatronic system-behaviour of the machine tool was pre estimated using a virtual mechatronic model. This allows for a virtual product design with a new and improved quality of safety in achieving the pre-defined goals.

关键词： HSC machining machine tool mechatronic simulation

来源：评论

学校读者我要写书评

暂无评论

Chuck system for integrated IR-based temperature measurement in rotational grinding of sapphire wafers 12

Chuck system for integrated IR-based temperature measurement...

引用

12th International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2012

作者： Klocke, F. Dambon, O. Herben, M. Veselovac, D. Adams, O. Kuljanic, E. Sortino, M. Totis, G. Fraunhofer Institute for Production Technology IPT Germany Laboratory for Machine Tools and Production Engineering RWTH Aachen University Germany Department of Electrical Management and Mechanical Engineering University of Udine Italy

ISBN: (纸本)9780956679000

Single crystalline sapphire wafers are used as a substrate for semiconductor and optoelectronic applications like gallium nitride-based LED light sources. In the optimization of the manufacturing chain, rotational grinding plays a mayor role by substituting the conventional lapping process in order to reduce cost intensive efforts in downstream polishing steps. Due the material properties of the sapphire and in particular its hardness of 9 on the Mohs Scale however, it is difficult to establish a stable finishing process. For this reason, the detection of in-process variables like the grinding temperature distribution in the contact zone between the wafer and the grinding wheel are of significant interest. On the one hand, the acquired data increase process understanding, enhancing grinding wheel and process development. On the other hand, real-time processing of the measurement data enables direct control of the process in order to achieve optimum stability. Within this paper, a novel chuck system for the measurement of contact zone temperatures is presented. The general behaviour of the realized system is examined in preliminary calibration tests and grinding tests are performed to prove the feasibility of the chuck system under common machining conditions.

关键词： Grinding (machining)

来源：评论

学校读者我要写书评

暂无评论

Lifecycle impact profile for efficient product development - Jet engine example 19

引用

19th CIRP Conference on Life Cycle Engineering, LCE 2012

作者： Hacker, Patrick Ansgar Schuh, Günther Von Czerniewicz, Frank Division Technology Management of Fraunhofer Institute for Production Technology Aachen Germany Department of Production Engineering Laboratory of Machine Tools and Production Engineering Aachen University Germany MTU Aero Engines GmbH Munich Germany

ISBN: (纸本)9783642290688

Development of jet engines faces increasing complexity. To cope with this efficiently the management of product development has to be strengthened. More frontloading is necessary to improve the efficiency of product development processes. Therefore new tools are required, especially to reduce time spend on iterative problem solving. These tools have to be different from existing Target Costing or Lifecycle Assessment tools. Based on results of psychology and solution space management, these new tools should enhance effective and creative problem solving. In this paper a method is proposed which addresses the detailed design phase by the example of jet engines.

关键词： Product development

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：