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Analytical Modelling of Milling Forces for Helical End Milling Based on a Predictive Machining Theory

Procedia CIRP 2015年 31卷 258-263页

作者： Zhongtao Fu Wenyu Yang Xuelin Wang Jürgen Leopold State Key Laboratory of Digital Manufacturing Equipment and Technology School of Mechanical Science and Technology Huazhong University of Science and Technology Wuhan430074 China Formerly Fraunhofer Institute for Machine Tools and Forming Technology Chemnitz09661 Germany

Milling forces play an importantrole in the milling process and are generally calculatedbythe mechanistic or numerical methods which are considered time-consuming and impractical forvarious cutting conditions and workpiece-toolpair. Therefore, this paper proposes an analytical method for modelling themilling forcesin helical end milling process based on a predictive machining theory, which regards the workpiece material properties, tool geometry, cutting conditions and types of milling as the input data. In this method,each cutting edge is discretized into a series of infinitesimal elements along the cutter axis and the cutting action of each elementis equivalent to the classical oblique cutting process. The three dimensional cutting force components applied on eachelement are predicted analytically using this predictive oblique cutting modelwith the effect of cutting edge radius. Finally, the proposed analytical model of milling forcesis verified by the publishedresultsandthe simulation values using the software AdvantEdgeFEM.

关键词： Analytical modelling Milling forces Helical end milling Predictive machining theory

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Analysis of Feature Extracting Ability for Cutting State Monitoring Using Deep Belief Networks

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Procedia CIRP 2015年 31卷 29-34页

作者： Yang Fu Yun Zhang Haiyu Qiao Dequn Li Huamin Zhou Jürgen Leopold State Key Laboratory of Material Processing and Die & Mold Technology Huazhong University of Science and Technology Wuhan 430074 P. R. China Formerly Fraunhofer Institute for Machine Tools and Forming Technology Chemnitz 09661 Germany

Information extracting method from numerous measured signals is a critical technique for intelligent manufacturing application to further reduce the manpower cost and improve the productivity and workpiece quality. Manually defining signal features,as the common way, unfortunately will lose most of the information and the performance can’t be guaranteed. In the past few years, machine learning method with deep structure has been the most promising automatic feature extracting method which has made great breakthrough in computer vision and automatic speech recognition. In this paper, deep belief networksareemployed using vibration signal obtained from endmilling to build feature space for cutting states monitoring. Greedy layer-wise strategy is adopted to pre-train the network and standard samples are used for fine-tuning by applying back-propagation method. Comparisons are made with several manually defined features both in time and frequency domain, like MFCC and wavelet method. Different modeling methods are also employed in the research forcomparisons. Resultsshow that the deep learning method has similar ability to characterize the signal for cutting states monitoring compared to those manually defined features. And the modeling accuracy ismuch better thanother traditionalmodeling ***, benefitting fromthe potentialcapability in information fusion, deep learning method would be a promising solution for more complex applications, like tool wear monitoring, machining surface prediction et al.

关键词： Intelligent manufacturing Cutting states monitoring Deep belief networks Feature extraction.

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Reducing blade manufacturing cost while maintaining aerodynamic performance of vertical axis wind turbines

Reducing blade manufacturing cost while maintaining aerodyna...

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European Wind Energy Association Conference and Exhibition 2014, EWEA 2014

作者： Domínguez, Diego Pröhl, Marco De Troyer, Tim Feng, Guoying Werner, Markus Runacres, Mark Department of Engineering Technology Vrije Universiteit Brussel Brussels Belgium Fraunhofer Institute for Machine Tools and Forming Technology IWU Chemnitz Germany

Vertical axis wind turbines have experienced a renewed impulse during the last few years, with important research efforts focused on them. This work is focused in the development of new blade designs capable of notably reduce their manufacturing cost and, consequently, improve global profitability. Thanks to the aerodynamic and structural analyses that have been carried out, a final blade design has been achieved. It is based on the use of hydroforming manufacturing techniques with metal sheets, creating 3 meters blades to be used in a turbine capable of produce about 1kW. First estimations show that with the positive effects of a mass use and production (economies of scale), such metal blades have a 90 % reduction potential in their production costs compared to fibre-reinforced ones for single turbines.

关键词： Turbomachine blades

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Integrated Requirements and Systems Modeling in the Mechatronic Development Process

Integrated Requirements and Systems Modeling in the Mechatro...

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International Conference on Developments in eSystems Engineering (DESE)

作者： Christoph Richter Georg Hackenberg Michael F. Zäh Gunther Reinhart Fraunhofer Institute for Machine Tools and Forming Technology Augsburg Germany Software & Systems Engineering Technische Universität München München Germany Institute for Machine Tools and Industrial Management Technische Universität München München Germany

Manufacturing systems continuously increase in complexity due to higher customer expectations regarding their purpose and flexibility of use. In addition, the growing meaning of electronic and software components in manufacturing systems complicates the engineering since the interaction of different disciplines leads to increasing coordination efforts and problems regarding the interfaces between these disciplines. For these reasons, development processes in this context need to be adapted continuously to the present situation. To face these challenges, the suitable handling of arising requirements is one key factor for the success of engineering processes. Therefore, a modeling technique for an integrated requirements and systems modeling in the mechatronic development process is presented in this paper. After a summary of approaches for model-based development and requirements engineering in the context of mechatronic systems, the modeling technique is illustrated on a meta-model level. To demonstrate the feasibility, the proposed approach is applied to a miniaturized packaging machine, which is currently developed at the institute for machine tools and Industrial Management (iwb) of Technische Universit München for benchmarking engineering methods and tools. Excerpts of this application are outlined in this paper as well as the results of a discussion with experts from the machine tools industry regarding the presented modeling approach. Finally, an outlook with respect to possible enhancements of the modeling technique is given.

关键词： Mechatronics Object oriented modeling Unified modeling language Requirements engineering Analytical models Software

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Characterisation of tool coatings for press hardening

Characterisation of tool coatings for press hardening

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6th International Conference on Tribology in Manufacturing Processes and Joining by Plastic Deformation, ICTMP 2014

作者： Müller, Roland Mosel, André Fraunhofer-Institute for Machine Tools and Forming Technology IWU Reichenhainer Straße 88 09126 Chemnitz Germany Chemnitz University of Technology Machine Tools and Forming Technology Straße der Nationen 62 09107 Chemnitz Germany

ISBN: (纸本)9783038351276

Hot sheet metal forming is gaining in importance in many fields, because of its capability to produce more complex components than possible with cold forming. Hot forming is also used to influence the final material properties with the hot forming of manganese-boron steels being a good example. One of the major challenges in hot forming is the tribological conditions between the tool and sheet material at the required high temperatures. This article will discuss the influence of different tool material coatings, ranging from PVD to mechanically bonded ceramic coatings, on the tribological conditions during forming. It will also shed light on how these coatings influence the heat transfer between the component´s material and the tool material. © (2014) Trans Tech Publications, Switzerland.

关键词： Heat transfer

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A pilot trial comparing the tear-out behavior in screw sockets and cemented polyethylene acetabular components – a cadaveric study

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Revue de Chirurgie Orthopedique et Traumatologique 2016年第6期102卷 530-530页

作者： Möbius, R. Schleifenbaum, S. Grunert, R. Löffler, S. Werner, M. Prietzel, T. Hammer, N. Institute of Anatomy University of Leipzig Faculty of Medicine Liebigstraße 13 Leipzig 04103 Germany Department of Orthopedics Trauma Surgery and Plastic Surgery University Hospital of Leipzig Liebigstraße 20 Leipzig 04103 Germany Fraunhofer Institute for Machine Tools and Forming Technology Nöthnitzer Straße 44 Dresden 01187 Germany HELIOS Clinic Blankenhain Germany Department of Anatomy University of Otago Lindo Ferguson Building 270 Great King St Dunedin 9016 New Zealand

Background The removal of well-fixed acetabular components following total hip arthroplasty (THA) is a difficult operation and could be accompanied by the loss of acetabular bone stock. The optimal method for fixation is still under debate. The aim of this pilot study was to compare the tear-out resistance and failure behavior between osseo-integrated and non-integrated screw cups. Furthermore, we examined examined whether there are differences in the properties mentioned between screw sockets and cemented polyethylene cups. Hypothesis Tear-out resistance and related mechanical work required for the tear-out of osseo-integrated screw sockets are higher than in non-integrated screw sockets. Patients and methods Ten human coxal bones from six cadavers with osseo-integrated screw sockets (n = 4), non-integrated (implanted postmortem, n = 3) screw sockets and cemented polyethylene cups (n = 3) were used for tear-out testing. The parameters axial failure load and mechanical work for tear-out were introduced as measures for determining the stability of acetabular components following THA. Results The osseo-integrated screw sockets yielded slightly higher tear-out resistance (1.61 ± 0.26 kN) and related mechanical work compared to the non-integrated screw sockets (1.23 ± 0.39 kN, P = 0.4). The cemented polyethylene cups yielded the lowest tear-out resistance with a failure load of 1.18 ± 0.24 kN. Compared to the screw cups implanted while alive, they also differ on a non-significant level (P = 0.1). Osseous failure patterns differed especially for the screw sockets compared to the cemented polyethylene cups. Discussion Osseo-integration did not greatly influence the tear-out stability in cementless screw sockets following axial loading. Furthermore, the strength of the bone–implant interface of cementless screw sockets appears to be similar to cemented polyethylene cups. However, given the high failure load, high mechanical load and because of the related bone failure

关键词： Acetabular component Acetabular revision Cementless fixation Osseo-integration Screw socket THA

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Fabrication Method for Series Production of Sheet Metal Parts with Integrated Piezoelectric Transducers

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Procedia technology 2014年 15卷 494-502页

作者： Matthias Nestler Welf-Guntram Drossel Sebastian Hensel Roland Müller Fraunhofer Institute for Machine Tools and Forming Technology IWU 09126 Chemnitz Germany

The paper presents a high volume compatible production method for the fabrication of sheet metal parts with integrated piezoelectric transducers. The functionality of the integrated piezomodule is shown on a wing assembly, consisting of two sheet metals shaped with roll bending and three point bending operations. The stimulation of the structure is performed with a shaker, the reduction of the acoustic noise was realized with the integrated piezomodule and monitored with vibrometer measurements. Impedance measurements were performed for health monitoring of the multiple bolted joint. Furthermore, a simulation of the structure was used for the determination of resonance frequencies. The results show a good correlation between experiment and simulation.

关键词： piezo-metal-compound adhesive MFC piecoelectic transducer vibration compensation health monitoring

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Multidimensional Analysis of Process Chains Regarding the Resource-efficient Manufacturing of Hybrid Structures

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Procedia CIRP 2015年 26卷 595-600页

作者： C. Fanghänel A. Rautenstrauch C. Symmank J. Katzenberger M. Putz V. Kräusel U. Götze B. Awiszus Fraunhofer Institute for Machine Tools and Forming Technology Reichenhainer Straße 88 09126 Chemnitz Germany Technische Universität Chemnitz Professorship for Machine Tools and Forming Technology Reichenhainer Straße 70 09126 Chemnitz Germany Technische Universität Chemnitz Professorship Management Accounting and Control Thüringer Weg 7 09126 Chemnitz Germany Technische Universität Chemnitz Professorship Virtual Production Engineering Reichenhainer Straße 70 09126 Chemnitz Germany

One of the leading topics in the automotive industry as well as in the aircraft and aerospace sector is the use of lightweight structures for weight reduction. For this purpose, hybrid materials, e.g. metal-plastic structures, are of essential importance. Despite the high technological challenge, the manufacturing techniques still provide versatile development potential. Especially the integration of separate production techniques in one single tool opens new possibilities of successfully designing a resource-efficient process chain for hybrid components, suitable for series production. Within the Cluster of Excellence “MERGE Technologies for Multifunctional Lightweight Structures”, a modelling approach for the resource-efficient process design of the manufacturing of hybrid structures, which is based on a multidimensional analysis, will be developed. Besides the technical optimisation, the energy efficiency, the cost-effectiveness, the robustness of process chains as well as the maturity regarding series production will be considered during the entire development process. The paper will present main features of this modelling approach including a proposal for a systematic and structured procedure of a multidimensional analysis.

关键词： cost-effectiveness energy efficiency hybrid components maturity analysis resource-efficient process chain robustness

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Tempered forming of Magnesium Alloys Using the Example of Roll forming

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Materials Today: Proceedings 2015年 2卷 S60-S66页

作者： K. Richter R. Haase F. Schieck D. Landgrebe Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Str. 88 09126 Chemnitz Germany

The sheet metal forming of magnesium alloys requires an adaption of the forming processes utilized. Due to limited formability at room temperature, heating above a temperature of 200 to 225 °C is necessary in order to activate additional gliding planes. By the example of roll forming, the temperature regime and implementation of heating equipment into the forming process is illustrated. On account of the progressive feed of sheet material necessary for roll forming, a transverse flux induction heating was used in the experimental setup. Results of experimental design and experimentation with AZ31 alloy will be presented in this paper.

关键词： Magnesium Alloys AZ31 Roll forming Inductive Heating

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Integrated Sensors System for Human Safety during Cooperating with Industrial Robots for Handing-over and Assembling Tasks

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Procedia CIRP 2014年 23卷 65-70页

作者： Mohamad Bdiwi Department of Joinging and Assembling Fraunhofer Institute for Machine Tools and Forming Technology IWU Chemnitz Germany

Human safety is the main concern which prevents performing some tasks requiring physical interaction between human and robot. Therefore, the safety concept was previously based on eliminating contact between human and robots. This paper will propose a robot system which integrates different types of sensors to ensure human safety during the physical human robot interaction. The implemented sensors are vision, force and sensitive skin. Using vision system, the robot will be able to detect and recognize human face, loadfree human hand and any object carried by human hand (active hand). Furthermore, it will help the robot to define in which directions the force should be applied and what are the dangerous directions for human safety. The force sensor will help the robot to react to the motion of the human hand during the handing-over or assembling task. The sensitive skin will prevent any collision between the human and the robot arm. The proposed system is supported with a voice system for informing human about the actual status of the system.

关键词： Human-robot interaction Human-safety visual servoing force control handing-over and assembly tasks

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