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Experimental Study on Micro forming of Structured Surfaces for High Static Friction Connection Elements

Procedia Manufacturing 2020年 47卷 1230-1234页

作者： Ingo Schaarschmidt Philipp Steinert Matthias Hackert-Oschätzchen Gunnar Meichsner Andreas Schubert Guido Jungblut Professorship Micromanufacturing Technology Faculty of Mechanical Engineering Chemnitz University of Technology 09107 Chemnitz Germany Chair of Manufacturing Technology with Focus Machining Otto von Guericke University Magdeburg 39106 Magdeburg Germany Fraunhofer Institute for Machine Tools and Forming Technology 09126 Chemnitz Germany Pro-Com A. Jungblut GmbH 66663 Merzig Germany

Bolt connections are the most prevalent technical solution to join several devices. To meet high requirements on lightweight constructions and safety-relevant technologies bolt connections require additional security elements or surface modifications to increase static friction without damaging the workpiece surface significantly. One possible solution is the micro structuring of the connection element surface within the conventional forming process chain. For the manufacturing of micro structured connection elements a micro structured forming tool is needed. Therefore, the forming tool has to feature a negative geometry of the connection element surface micro geometry. Requirements on forming tool materials are high hardness in combination with high wear resistance and good toughness. Suitable technologies to manufacture such micro structured metal dies are laser beam machining (LBM), electrochemical machining (ECM) and electrical discharge machining (EDM), respectively. In this study the micro forming process of high static friction connection elements is investigated. The manufactured connection element surfaces are analyzed after the forming experiments and the results are associated with the surfaces of the metal dies. Therefore the surfaces of the utilized metals dies are compared with each other and with a grinded reference surface and characteristic parameters are analyzed. The comparison is based on the resulting surface roughness parameters and surface conditions before and after lubricated forming experiments. At least wear of the metal dies after multiple forming operations is analyzed. As one result, ECM manufactured metal dies have shown a high degree of replication in combination with high wear resistance.

关键词： Micro forming Static friction Connection element

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Incremental sheet metal forming on the example of car exterior skin parts

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Procedia Manufacturing 2019年 29卷 105-111页

作者： Sören Scheffler Alexander Pierer Peter Scholz Sebastian Melzer Dieter Weise Zdeněk Rambousek Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Straße 88 09126 Chemnitz Germany VÚTS a.s. Svárovská 619 Liberec XI-Růžodol I 460 01 Liberec Czech Republic

In this article, current, application-related investigations in the field of incremental sheet metal forming (ISF) will be presented and discussed. The main focus of the study will be on the chain of conceptual design, experimentation and subsequent work processes, right through to the final assembly of car exterior skin parts of a streamlined vintage concept car. This will be accompanied by a comparison and evaluation of different production technologies with regard to their economic efficiency, their real duration times and the specific boundary conditions for the manufacturing of just one part per geometry. The manufacturing processes at the centre of the study were: deep drawing, hydroforming and ISF (Two Point Incremental forming (TPIF) and rolling). Following the holistic discussion on the procedure and choice of processes, the TPIF is examined in detail using the example of the rear mudguards.

关键词： Incremental Sheet Metal forming Two Point Incremental forming Sheet Metal forming forming machine Design

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Wishbone made of hybrid aluminum foam sandwich

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Lightweight Design worldwide 2018年第2期11卷 36-41页

作者： Claudia Drebenstedt Camilo Zopp Alexander Hackert Lothar Kroll Fraunhofer Institute for Machine Tools and Forming Technology IWU Chemnitz Germany TU Chemnitz Germany

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Zero-error-production through inline-quality control of presshardened automotive parts by multi-camera systems

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IOP Conference Series: Materials Science and Engineering 2021年第1期1157卷

作者： A Pierer T Wiener L Gjakova J Koziorek Fraunhofer-Institute for Machine Tools and Forming Technology Chemnitz Germany VŠB - Technical University of Ostrava Faculty of Electrical Engineering and Computer Science Ostrava Czech Republic

Visual inspection often represents a bottleneck in the production chain due to limited receptivity and human fatigue. Depending on the inspection task, human classification error decisions greater than 10% are not uncommon. In order to make the manufacturing process more robust and sustainable, this paper presents innovative automated inline monitoring to realize a zero-error strategy in the field of industrial manufacturing. The central idea is to detect surface defects in the running production process by data fusion of a multi-camera system. Due to the required data analysis in conjunction with the targeted high throughput rates in production, this generates large amounts of data to process. Massively parallel hardware structures are used to enable defect detection within the production cycle. The paper especially addresses how to tackle boundary conditions in productive press-lines like the software-based mitigation of placement tolerances of parts and real-time capabilities. As a result, benefits could be achieved in terms of minimum detectable failure sizes and inspection speed, enabling 100% inline inspection of produced parts. The feasibility of the presented approach is demonstrated on realistic press-hardened deep-drawn automotive parts.

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Structural loading of cellular metals: Damage mechanisms and standardization concepts 10th

Structural loading of cellular metals: Damage mechanisms and...

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10th International Conference on Porous Metals and Metallic Foams, MetFoam 2017

作者： Krupp, Ulrich Hipke, Thomas Nesic, Srecko Institute of Materials Design and Structural Integrity University of Applied Sciences Osnabrück Osnabrück49009 Germany Fraunhofer Institute of Machine Tools and Forming Technology IWU Chemnitz09126 Germany

ISBN: (纸本)9783035712315

Structural loading of cellular metals is strongly affected by brittle fracture of cell struts and walls that exhibit tensile loads, e.g., during fatigue loading. The present paper summarizes results of compression, tension and cyclic loading experiments on various closed-cell metal foams and metal foam sandwiches (Alulight, Alporas, Foamtech, AFS) using various mechanical testing systems. The results were correlated with a thorough analysis of the cellular mesostructure and the cell strut/wall microstructure by means of scanning electron microscopy revealing defects, such as casting porosity and large Si precipitates in the Al-Si eutectic of aluminum cast alloy. The results of the work served for the definition of testing standards for compression testing (ISO 13314) and tensile testing (DIN 50099), which are outlined in the paper. Such standards and design guidelines are crucial for a successful implementation of cellular metals in innovative products in mechanical, automotive and energy engineering as well as in bioengineering. © 2018 Trans Tech Publications, Switzerland.

关键词： Tensile testing

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Modelling of surface formation mechanism during burnishing of aluminium

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Procedia CIRP 2019年 82卷 450-454页

作者： Rico Stöckmann Matthias Putz Technische Universität Chemnitz Institute for Machine Tools and Production Processes Reichenhainer Str. 70 09126 Chemnitz Germany Fraunhofer Institute for Machine Tools and Forming Technology Reichenhainer Str. 88 09126 Chemnitz Germany

Burnishing is a finishing process which levels the roughness of machined surfaces and increases the hardness by micro-forming. In this paper, a novel two-dimensional finite element model for the diamond ball burnishing process on aluminium is presented, which allows a prediction of the surface structure. The force, step over distance, and tool geometry during the burnishing process are taken into account by the model and the results are verified by experimental investigations. The verification shows that the model is able to predict all geometrical surface aspects like roughness, sinking-in and bulge formation for reasonable process parameters.

关键词： Finite element method (FEM) Surface modification Burnishing

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Decision Support for Planning Techniques in Energy Efficiency Projects

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Procedia CIRP 2018年 69卷 306-311页

作者： Marian Süße Johannes Stoldt Andreas Schlegel Matthias Putz Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Straße 88 09126 Chemnitz Germany

Factory operators can select from a multitude of measures to improve their energy efficiency. Despite the variety of planning techniques intended to help investigating the energy flows, little assistance is available for determining the most efficient approach to pursue in a specific project. This paper presents decision support procedures for making appropriate selections during planning, focusing on the selections of an energy model and a matching energy data acquisition method. They build on problem-independent decision models and systematize available alternatives. The models are solved independently by applying the Analytic Hierarchy Process that allows the integration and quantification of different criteria.

关键词： Energy efficiency Sustainable development Decision-making Analytic Hierarchy Process

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Minimally-invasive lag screw fixation technique for posterior malleolus fractures: A cadaveric study

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Foot & Ankle Surgery: Techniques, Reports & Cases 2024年第2期4卷 100385-100385页

作者： Fullarton, M., MSc Vidakovic, H., FRACS Kieser, D.C., PhD, FRACS Hammer, N., PhD Wyatt, M.C., MD, FRACS University of Otago Department of Anatomy Dunedin New Zealand University of Otago Department of Orthopaedics and Musculoskeletal Medicine Christchurch New Zealand Medical University of Graz Division of Macroscopic and Clinical Anatomy Gottfried Schatz Research Center Graz Austria Department of Trauma Orthopedic and Plastic Surgery University Hospital of Leipzig Germany Fraunhofer Institute for Machine Tools and Forming Technology Division of Biomechatronics Dresden Germany College of Health Massey University New Zealand

AbstractAnatomical reduction and lag screw fixation of posterior malleolar (PM) ankle fractures typically involves an open posterolateral approach. The aim of this anatomical study was to assess whether a minimally-invasive, percutaneous posterior-to-anterior lag screw fixation technique is safe to perform. Eighteen cadaveric ankle specimens were used. A transverse incision was made at the lateral border of the Tendo Achilles (TA). Windows were made lateral to and through the substance of the TA and simulated reduction and placement of a single lag screw performed. Specimens were then fully dissected to ascertain proximity and damage to anatomical structures. Lag screw fixation was placed appropriately in all ankles. No injury to the neurovascular structures, ankle joint or syndesmotic ligaments was observed. The mean distance from the soft tissue window to sural nerve was 10.0 mm (range 5–16), and 9.5 mm to short saphenous vein (4–14). Whilst the muscle belly of flexor hallucis longus (FHL) was pierced in six specimens, no injuries to the FHL tendon were observed. The mean distance from screw to syndesmosis was 9.3 mm (range 3–15) and 12.7 mm to the ankle joint (7–17). This study demonstrates that posterior percutaneous lag screw fixation is both safe and accurate. Further work is required to evaluate the precision of reduction and the biomechanical stability of this fixation technique. This novel minimally-invasive technique may be beneficial in avoiding the wound complications associated with open posterolateral ankle approaches and also offer a functional advantage due to minimal soft tissue disruption.

关键词： Ankle joint Approach Fixation Posterior malleolus fracture Trauma V

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Methodology and model for predicting energy consumption in manufacturing at multiple scales

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Procedia Manufacturing 2018年 21卷 694-701页

作者： Jan Reimann Ken Wenzel Marko Friedemann Matthias Putz Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Straße 88 09126 Chemnitz Germany

Certain fields of manufacturing, like casting, forming or cutting, may cause high energy load. Especially under the consideration of renewable energy sources it is beneficial to negotiate production schedules and consumption forecasts with the energy supplier. This would enable an optimized management of energy sources and infrastructure components on the supplier side, helping to reduce costs. Optimal and balanced expenses for production would be the consequence. The problem of power consumption prediction in manufacturing was subject of many studies in the past. Most of them either consider the physical modeling of processes at a very detailed level, or they introduce tailored prediction models for specific production processes. Thus, it is hard to apply their results to other uses cases in different scenarios. As a consequence, a generic methodology and model regarding power consumption prediction in manufacturing is required in order to cover the variety of processes, machines and materials. Furthermore, an approach must support flexible levels of granularity for predicting the energy consumption of manufacturing processes. On the one hand, a whole factory may be the object of investigation while, on the other hand, predictions for finer-grained levels, such as certain parts of a machine, are required to allow for specific optimizations. Our contribution is twofold. First, we propose a generic model for the specification of the power-consuming machine. A tree-based compositional approach supports arbitrary levels, depending on the structure of the machine, or external factors, such as company policies. This approach is highly extensible since the models are stored in ontologies. Second, we propose a methodology for static and dynamic modeling of power consumption for every structural level. Based on that model the prediction can be realized. In addition, we provide an example implementation and prediction for a continuous casting machine process.

关键词： Energy efficiency Predictive Model Ontology

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Product Flexible Car Body Fixtures with Position-dependent Load Balancing Based on Finite Element Method in Combination with Methods of Artificial Intelligence

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Procedia CIRP 2018年 67卷 452-457页

作者： Rayk Fritzsche Andreas Richter Matthias Putz Head of group assembly systems at Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Strae 88 Chemnitz 09126 Germany Scientific employee at Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Strae 88 Chemnitz 09126 Germany

In car-body production, the fixtures used for fixing the car-body panels during the joining processes predominantly consist of rigid constructions that are precise and specific for one car-model. In addition to the already presented automatic adaptation of such fixtures, and specific for the production of many different car-models using same fixture, different clamping robots have been developed. In order to meet the high quality requirements, the positional deviations of these clamping robots are adjusted due to different external loads. This control loop is carried out using a combination of finite element method, mathematical algorithms and modern methods of artificial intelligence.

关键词： Quality management Body in white Rramp up Artificial intelligence Neuronal network Database

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