检索结果-内蒙古大学图书馆

Modeling of the wet immersed tumbling process with the Discrete Element Method (DEM)

Procedia CIRP 2021年 102卷 1-6页

作者： E. Uhlmann J.-P. Fürstenau Y. Kuche S. Yabroudi J. Polte M. Polte Institute for Machine Tools and Factory Management IWF Technische Universität Berlin Pascalstr. 8-9 Berlin 10587 Germany Fraunhofer Institute for Production Systems and Design Technology IPK Pascalstr. 8-9 Berlin 10587 Germany CADFEM GmbH Pelikanstr. 13 Hannover 30177 Germany

Immersed tumbling is an industrially established process for finishing of components made of metal, ceramic or plastic. In this process, the components are completely surrounded by a wet, abrasive medium, which allows burrs to be removed and surfaces to be polished. In order to gain specific insights into the influence and flow properties of the abrasive media used in this process, numerical approaches using the Discrete Element Method (DEM) with the Rocky DEM software are presented within these investigations. A complete process simulation could be realised by means of a digital machine tool. The immersed tumbling process with cone-shaped polymer abrasive media is implemented by use of a liquid bridge model. The results were validated by experiments with an industrially used immersed tumbling machine tool and for the first time allow sound statements about the contact conditions and interactions of the abrasive media with the workpiece.

关键词： discrete element method DEM immersed tumbling liquid bridge facetted particles

来源：评论

学校读者我要写书评

暂无评论

Fully coupled wet cylindrical turning simulation using the Finite-Pointset-Method

引用

Procedia CIRP 2021年 102卷 43-48页

作者： Eckart Uhlmann Enrico Barth Alexander Quellhorst Tobias Seifarth Jörg Kuhnert Kaissar Nabbout Martin Sommerfeld Technische Universität Berlin Institute for Machine Tools and Factory Management (IWF) Chair of Machine Tools and Manufacturing Technology Pascalstr. 8-9 10587 Berlin Germany Fraunhofer Institute for Production Systems and Design Technology (IPK) Pascalstr. 8-9 10587 Berlin Germany Fraunhofer Institute for Industrial Mathematics ITWM Fraunhofer-Platz 1 67663 Kaiserslautern Germany Otto von Guericke University Magdeburg Institute of Process Engineering Universitaetsplatz 2 39106 Magdeburg Germany

In industrial machining operations, many turning processes are carried out under wet conditions. In contrast, most simulation tools are only suitable for dry cutting processes due to challenges of modeling fluid-structure-interactions (FSI). In this paper, a wet, fully coupled cutting simulation using the Finite-Pointset-Method (FPM) is presented and validated for industrially relevant cylindrical turning. To facilitate the required reduction of the calculation effort, different routines like adaptive numerical discretization are applied. The results indicate different cutting fluid effects like evaporation areas around the chip.

关键词： Turning Cutting fluid Simulation

来源：评论

学校读者我要写书评

暂无评论

production environment of tomorrow (ProMo): Partially automated repair process of small tool moulds, forming tools, injection moulding tools and sand casting tools

引用

IOP Conference Series: Materials Science and Engineering 2021年第1期1140卷

作者： Jan Kuschan Vinzenz Müller Stephan Monchinger Oliver Heimann Carsten Niebuhr Oday Kabha Fraunhofer Institute for Production Systems and Design Technology IPK Germany

Small defects in the grain or major damage to a moulded part or tool can bring production to a standstill. SMEs in particular have neither the personnel nor the equipment to repair such damage on their own, so they send it to specialised contractors. The repair process is carried out manually, depending on the accuracy requirements, and is usually completed by a finishing process. This work requires qualified personnel and, at the same time, requires a lot of time in case of larger damages. In this paper we present a way to map the Maintenance, Repair and Operations (MRO) process chain in a partially automated manner. The symbiosis of individual technologies results in a significantly increased efficiency of the MRO process chain, which continues to focus on people and their process knowledge. While Directed Energy Deposition (DED) for the MRO of moulded parts is used widely, usually a high manual effort in measuring the component geometries and teaching of the machine tool paths is necessary. However, there are clear advantages compared to the manufacture of new parts or manual laser welding repair. At the same time, the resource and energy requirements can often be significantly reduced compared to new part production. Promo focuses on automating the time-consuming machine programming by reducing the number of necessary work steps in CAD/CAM-based program creation. Based on a subsequent robot-guided scan, a digital actual 3D model is generated. Due to intelligent path planning algorithms, no manual programming of the robot is necessary and at the same time it is possible to detect components of different sizes, shapes and covers in this system with a minimum of effort. In addition, the operator passes on elementary information, such as the approach path of the milling head, to the subsequent processes by means of finger gestures and can thus significantly reduce tedious CAM programming steps. Now, the scanned component is transferred to a 3D-CAD model and a target

关键词：

来源：评论

学校读者我要写书评

暂无评论

Process behaviour of micro-textured CVD diamond thick film cutting tools during turning of Ti-6Al-4V

引用

Procedia CIRP 2020年 87卷 25-30页

作者： Eckart Uhlmann Danny Schröter Institute for Machine Tools and Factory Management (IWF) Technische Universität Berlin 10587 Berlin Germany Fraunhofer Institute for Production Systems and Design Technology (IPK) 10587 Berlin Germany

Currently, an efficient machining of high-performance materials, such as titanium alloy Ti-6Al-4V, represents a challenge in manufacturing. For the reduction of high cutting temperatures, micro-textured CVD diamond thick film cutting tools establish new potentials regarding the process productivity. The application of micro-textures allows a reduced contact area between chip and tool in order to decrease the generation of heat. Furthermore, a direct application of lubricant into the cutting zone is possible. The present study investigates the influence of micro-textured CVD diamond thick film cutting tools on the resulting process forces, chip formation as well as maximum cutting volumes during turning process. Part of the investigations was a variation of micro-texture trajectory with micro-textures parallel to the major cutting edge, perpendicular to the bisector of corner angle ε and curved along the cutting edge. The analyses showed that both positive and negative effects occur using micro-textures. The forces can be reduced by 14 % whereas the use of micro-textures leads to higher feed forces F f by 21 % as well as an additional notch effect in the micro-texture bottom.

关键词： CVD diamond thick film micro-texture Ti-6Al-4V turning

来源：评论

学校读者我要写书评

暂无评论

AI-enhanced Identification, Inspection and Sorting for Reverse Logistics in Remanufacturing

引用

Procedia CIRP 2021年 98卷 300-305页

作者： Marian Schlüter Hannah Lickert Katharina Schweitzer Pinar Bilge Clemens Briese Franz Dietrich Jörg Krüger Fraunhofer IPK - Institute for Production Systems and Design Technology Pascalstr. 8-9 10587 Berlin Germany Technische Universität Berlin Institute for Machine Tools and Factory Management Pascalstr. 8-9 10587 Berlin Germany acatech – Deutsche Akademie der Technikwissenschaften Karolinenplatz 4 80333 München Germany

In a circular economy for remanufacturing, after each life cycle used products are returned to a remanufacturer for identification, inspection, sorting and reprocessing. Shortcomings and requirements of the remanufacturing market are identified through expert interviews and process analysis. A concept is proposed to enable an improved identification and a more objective inspection by enhancing the working environment and processes of sorting stations. Digitization and machine learning are applied on business data, using machine vision as well as sensor and actor skills of the worker. With an experimental case study on visual object recognition a positive impact on identification and thus sorting could be demonstrated.

关键词： Circular Economy Remanufacturing Reverse Logistics Sorting Computer Vision Machine Learning Assistance system

来源：评论

学校读者我要写书评

暂无评论

Data augmentation for inertial sensor based human action recognition using deep learning

引用

AIP Conference Proceedings 2024年第1期2989卷

作者： Jan Kuschan Hristo Filaretov Jörg Krüger Process Automation and Robotics Fraunhofer Institute for Production Systems and Design Technology IPK Pascalstr. 8-9 10587 Berlin Germany Industrial Automation Technology Institute of Machine Tools and Factory Management Technical University Berlin Pascalstr. 8-9 10587 Berlin Germany

Human Activity Recognition (HAR) approaches are predominantly based on supervised deep learning and benefit from large amounts of labeled data—an expensive resource. Data augmentation enriches labeled datasets by adding synthetic data, which is substantially cheaper, and often results in improved model performance, but is very rarely used for sensor data. This work explores data augmentation for inertial-sensor-based HAR by transforming the data through physically interpretable operations. The main studies were conducted on the Opportunity and the Overhead Car Assembly (OCA) datasets. For these experiments, only 20% of the available training data were used, and the experiments were conducted in an 8-fold cross-validation procedure over different subsets of the training *** results show that simple geometric augmentations can be beneficial in many cases. Timewarping proved to offer the most reliable single augmentation, improving the average F1 score of Opportunity from 0.570 to 0.597 and of OCA Mixed from 0.884 to 0.906. Combining augmentations improved the accuracy in almost all scenarios but to a degree comparable to timewarping. Applying augmentations on all the available training data improved the F1 score compared to the base case with no augmentations, although this effect is more pronounced for datasets with more similar training and test data: for the OCA Mixed variant, the average F1 score improved from 0.917 to 0.933, while for the OCA Leave-One-Out (LOT) variant, the average F1 score did not significantly change. For Opportunity, which similarly to OCA LOT uses a participant-based training-test split, the F1 score improved from 0.684 to 0.697.

关键词：

来源：评论

学校读者我要写书评

暂无评论

User centered development of a Digital Twin concept with focus on sustainability in the clothing industry

引用

Procedia CIRP 2020年 90卷 660-665页

作者： Theresa Riedelsheimer Lisa Dorfhuber Rainer Stark Fraunhofer-Institute for Production Systems and Design Technology (IPK) Pascalstrasse 8-9 10587 Berlin Germany Technical University Berlin Pascalstrasse 8-9 10587 Berlin Germany

The optimization of a product's socio-economic and environmental impact is gaining more relevance for customers and regulating institutions. Still, there is a gap between sustainable attitude and behavior. In this context, new technologies are explored to stimulate sustainable consumers' behavior. This paper aims at analyzing the concept of a Digital Twin and its sustainability impact. The authors present a user centered development of a Digital Clothing Twin with the aim to foster sustainability in the Mid-of-life and End-of-Life-phase. The sustainability impact of the Digital Twin concept as a potential solution as well as part of the problem is discussed.

关键词： Life Cycle Sustainability Assessment (LCSA) Life Cycle Assessment (LCA) Digital Twin Sustainability Smart products Use case

来源：评论

学校读者我要写书评

暂无评论

Demand-oriented barriers and potentials for remanufacturing in Vietnam

引用

International Journal of Sustainable Manufacturing 2020年第2-4期4卷 336-349页

作者： Guidat, Thomas Wewer, Aleksandra Kohl, Holger Seliger, Günther Department of Machine Tools and Factory Management Technische Universität Berlin Pascalstraße 8-9 Berlin10587 Germany Vietnamese German University Lê Lai Đinh Hoà Thů Dâu Môt Bình Dương Viet Nam Fraunhofer Institute for Production Systems and Design Technology IPK Pascalstraße 8-9 Berlin10587 Germany

Since the liberalisation of its economy, Vietnam has emerged as a key location for investment in workforce-intensive assembly processes operation, through an available and cheap workforce. Soaring national consumption levels for goods and services generate in turn unprecedented quantities of waste to be treated locally. In 2015, governmental decision 16/2015/QĐ-TTg set a basis for a national waste legislation for mechanical and electronic equipment goods. Remanufacturing is a non-destructive, industrial reuse strategy which aims at restoring products to original specifications by reusing a maximum number of original components in their current form. It has potential to provide Vietnam with an alternative to low value-added repair activities. As Vietnam is the fourth market for motorcycles in the world, this paper presents a case study about barriers and potentials for remanufacturing from the market and customer perspective. Potential solutions for supporting industrial development are suggested. © 2020 Inderscience Enterprises Ltd.

关键词： Motorcycles

来源：评论

学校读者我要写书评

暂无评论

With synthetic data towards part recognition generalized beyond the training instances

引用

AIP Conference Proceedings 2024年第1期2989卷

作者： Paul Koch Marian Schlüter Jörg Krüger Fraunhofer Institute for Production and System Design Technology Pascalstraße 8-9 10587 Berlin Germany Technical University Berlin Institute for Machine Tools and Factory Management Pascalstraße 8-9 10587 Berlin Germany

In this work we investigate the effect of using synthetic data, generated in a simulation, in order to pre-train an AI-based image classification for industrial components. After pre-training we use real camera-captured training images to fine-tune the AI with the aim to close the Sim2Real domain gap. We compare our approach to purely using real training images of a single candidate object instance. In an exemplary case study for screw recognition, we found that a given AI classification algorithm dropped its recognition rate from 99.8% to 88.5% when testing the algorithm with known and unknown screw instances of the learned object classes, respectively. Employing our pre-training method on the basis of synthetic data, the drop in recognition rate is decreased from 99% to 96.95%. Thus, our proposed method has only a relative drop of 2.05% when shifting towards a generalized domain (including unknown part instances), while a compared approach on the basis of real camera-captured data showed a drop of 11.3%.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Micro-cutting of a MMC-composite for enhanced injection moulds 19

Micro-cutting of a MMC-composite for enhanced injection moul...

引用

19th International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2019

作者： Uhlmann, E. Polte, M. Hein, C. Polte, J. Jahnke, C. Fraunhofer Institute for Production Systems and Design Technology IPK Germany Institute for Machine Tools Factory Management IWF Technische Universität Berlin Germany

ISBN: (纸本)9780995775145

Tools for micro-injection moulding are currently made of hardened steel. These tools are exposed to high local loads, which significantly reduce the injection moulding tool life time tT. Furthermore, the occurring wear of the milling tool during machining of hardened steel leads to reduced surface roughness Ra and geometrical accuracy GF. Copper and aluminium alloys as mould materials provide an alternative to hardened steel with advantages regarding material removal rate QW and wear of the milling tool, but with a significantly reduced life time of the injection moulding tool tT. Until now, the combination of a good machinability and high wear resistance cannot be achieved. The approach, presented in this paper consists of an easy to machine material and the development of a wear resistant metal-matrix-composite (MMC) material layer with a hardness of up to 3,000 HV. Therefore, the pre-machined test specimens made of aluminium-bronze are coated by laser dispersing with wolfram-carbide-particles W2C-WC. Furthermore, for the finishing machining of the coated moulds, a cutting technology for the machining of W2C-WC-particles was developed. The verification of the developed technology was performed with an injection moulding process based on carbon-fibre reinforced thermoplastic material. By means of documented machining efforts, the quality indicators geometrical accuracy GF and surface roughness Ra as well as occurring tool wear, the feasibility of the developed technology was demonstrated. © 2019 European Society for Precision Engineering and Nanotechnology, Conference Proceedings - 19th International Conference and Exhibition, EUSPEN 2019. All rights reserved.

关键词： Injection molding

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：