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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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Multiphysics Simulation of the Material Removal in Jet Electrochemical Machining

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Procedia CIRP 2015年 31卷 197-202页

作者： Matthias Hackert-Oschätzchen Raphael Paul Michael Kowalick André Martin Gunnar Meichsner Andreas Schubert Professorship Micromanufacturing Technology Faculty of Mechanical Engineering Technische Universität Chemnitz D-09107 Chemnitz Germany Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Strasse 88 D-09126 Chemnitz Germany

Jet Electrochemical Machining (Jet-ECM) is a technology for quickly and flexibly generating micro structures and micro geometries in metallic parts independently from the material's hardness and without any thermal or mechanical impact [1] . In the process no tool wear occurs and the machined surface is very smooth [2] . The Jet-ECM process strongly depends on the shape of the electrolyte jet. In a previous study Hackert [3] built a numerical model with COMSOL Multiphysics based on a predefined jet shape. The simulated dissolution results of this model progressively differ from experimental results with increasing processing time. Hence, a multiphysics model which integrated fluid dynamics using the level set method for two-phase flow was created. Furthermore, in the present study the electric boundary resistance at the interface of workpiece and electrolyte is considered. According to the real Jet-ECM process the simulation is divided into two steps. In the first simulation step the jet is formed, and in the second simulation step the anodic dissolution is simulated by deforming the geometry. The dynamic behavior of the electrolyte jet could be simulated during the material removal process. So effects became visible which affect the machining results.

关键词： Jet Electrochemical Machining localized anodic dissolution continuous electrolytic free jet multiphysics simulation boundary resistance

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Manufacturing of micro fluidic moulds by combining micro milling and laser structuring 14

Manufacturing of micro fluidic moulds by combining micro mil...

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14th International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2014

作者： Schubert, A. Gross, S. Eckert, U. Edelmann, J. Fraunhofer Institute for Machine Tools and Forming Technology IWU Germany

ISBN: (纸本)9780956679031

Increasing demands regarding the functionality and the functional density of micro fluidic systems require constant miniaturisation of single components and also of the complete system. A cost efficient and effective manufacturing process requires replication processes such as injection moulding or hot embossing to structure disposables cost-effectively. This paper presents the development of the sequential process combination of laser micro structuring and micro milling for the manufacturing of micro fluidic moulds.

关键词： Injection molding

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Making Sustainability Paradigms a Part of PPC

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Procedia CIRP 2015年 29卷 209-214页

作者： Matthias Putz Johannes Stoldt Christin Fanghänel Annett Bierer Andreas Schlegel Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Strasse 88 09126 Chemnitz Germany HTWK Leipzig – Faculty of Business Administration Gustav-Freytag-Straße 42a04277 Leipzig Germany

The mounting pressure of the European legislative to improve the sustainability of production operations prompts companies to implement sustainability paradigms into their production planning and control (PPC). First results from an ongoing European project will show how the innovative Resource Networks Methodology can be used to alter the production organisation accordingly. In particular, novel PPC strategies improving the integration of renewable energy sources and other resource efficient technologies by using previously identified levels of flexibility will be presented. These are complemented by an approach for unifying the readiness levels for application (RLA) of similar methodologies. The latter will assist decision making during the development phase and in preparation for industrial implementations.

关键词： Production planning Sustainable development Readiness levels Resource networks

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Evaluating mobile machine tool dynamics by substructure synthesis

Evaluating mobile machine tool dynamics by substructure synt...

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WGP Congress 2014

作者： Law, Mohit Rentzsch, Hendrik Ihlenfeldt, Steffen Fraunhofer Institute for Machine Tools and Forming Technology IWU Chemnitz Germany

ISBN: (纸本)9783038352457

Mobile machining solutions use autonomous machining units that can be transported to different part locations, making possible easy maintenance and repair of large industrial equipment. Every new part and location results in different boundary conditions for the mobile machine toolpart system, influencing the dynamics of the combined system and necessitating different strategies for part/machine referencing and clamping. To facilitate efficient mutability and modularity in mobile machining solutions, this paper presents a dynamic substructuring strategy that combines the response characteristics of the mobile machine unit with that of two different simulated base models under varying levels of contact stiffness and damping to obtain the synthesized mobile machine tool dynamic response. Numerical verification of the approach is provided. The framework presented can also combine measured response of parts for which models may not be available a priori. Methods presented provide experimental guidelines for establishing strategies for part/machine referencing and planning of machining strategies based on the esaluated dynamics. © (2014) Trans Tech Publications, Switzerland.

关键词： Dynamics

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Development of Patient-specific Orbital Floor Implants Made of Shape Memory Alloys

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Procedia CIRP 2016年 49卷 143-146页

作者： Ronny Grunert Jürgen Lichtenstein Nicole Preßler Matthias Geßner Christian Rotsch Maximilian Wagner Susanna Posern Friedemann Pabst Welf-Guntram Drossel Fraunhofer Institute for Machine Tools and Forming Technology IWU Nöthnitzer Straße 44 01187 Dresden Germany Universitätsklinikum Leipzig Klinik und Poliklinik für Orthopädie Unfallchirurgie und Plastische Chirurgie Liebigstraße 20 04103 Leipzig Germany Medizinische Hochschule Hannover Klinik und Poliklinik für Mund- Kiefer- und Gesichtschirurgie Carl-Neubergstraße 1 30625 Hannover Germany Krankenhaus Dresden Friedrichstadt Klinik für Hals-Nasen-Ohrenheilkunde Kopf- und Hals-Chirurgie Plastische Operationen Friedrichstraße 41 01067 Dresden Germany

The shape memory alloy NiTi has successfully proved in many areas of medical technology. This paper describes the innovative idea and development of orbital floor implants made of NiTi. Pseudoelastic NiTi has the peculiarity to withstand large mechanical deformations of up to 8% without being plastically deformed, i.e. it returns to its original shape with relief of the strain. This material property can be used to produce flexible, yet stable implants. The NiTi implants can be implanted into the body in compressed form through relatively small approaches. Arriving at the fracture position, they develop self-reliantly in the previously memorized shape. The perioperative trauma is reduced. The treatment of orbital floor fractures is often done surgically by use of implants made of rigid materials such as titanium, which are inserted in the eye socket through an open approach on the lower eyelid. Implants made of a pseudoelastic shape memory alloys can help to reduce the required incision length of the approach. It is even possible to insert the implant in a minimally invasive procedure via endoscopic access routes and to completely avoid open approach. In this paper first design variants of pseudoelastic orbital floor implants are presented and considerations on the manufacturing process are made.

关键词： NiTi orbital floor fracture orbital reconstruction patient-specific implants shape memory alloys

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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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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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Tailoring properties of commercially pure titanium by gradation extrusion

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AIP Conference Proceedings 2016年第1期1769卷

作者： Markus Bergmann Anja Rautenstrauch René Selbmann Raoni Barreto de Oliveira Rodrigo Santiago Coelho Dirk Landgrebe Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Str. 88 09126 Chemnitz Germany Technische Universität Chemnitz Institute of Machine Tools and Production Processes IWP Reichenhainer Straße 70 09126 Chemnitz Germany SENAI Cimatec Av. Orlando Gomes 1845 – Piatã 41650-010 – Salvador Brazil

Commercially pure titanium (CP Ti) is of great importance in medical applications due to its attractive properties, such as high biocompatibility, excellent corrosion resistance and relatively low density and suitable stiffness. Compared to the commonly used Ti-6Al-4V alloy, its lower strength has to be increased. The most attractive approach is to subject CP Ti to severe plastic deformation (SPD) processes such as Equal Channel Angular Pressing (ECAP). The resulting decreased grain size in CP Ti yields a significant increase in hardness and strength. Common SPD-processes typically provide a uniform modification of the material. Their material efficiency and productivity are critical and limiting factors. A new approach is to tailor the material properties by using Gradation Extrusion, which produces a distinct gradient in microstructure and strength. The forming process combines a regular impact extrusion process and severe plastic deformation in the lateral area of the material. This efficient process can be integrated easily into forming process chains, for instance for dental implants. This paper presents the forming process and the applied die geometry. The results of numerical simulations are used to illustrate the potential of the process to modify and strengthen the titanium material. Experiments show that the material is successfully processed by gradation extrusion. By characterizing the hardness and its distribution within the formed parts the effects of the process are investigated.

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