检索结果-内蒙古大学图书馆

Machinability study in orthogonal cutting of additively manufactured Inconel 718 with specifically induced porosity

Procedia CIRP 2024年 121卷 168-173页

作者： S.A.M. Schneider Y. Li J. Boseila P. Ganser T. Bergs J.H. Schleifenbaum Fraunhofer Institute for Production Technology IPT Steinbachstrasse 17 52074 Aachen Germany Chair of Digital Additive Production RWTH Aachen University Campus-Boulevard 73 52074 Aachen Germany Laboratory for Machine Tools and Production Engineering (WZL) of RWTH Aachen University Campus-Boulevard 30 52074 Aachen Germany

In comparison to conventional manufacturing technologies, additive manufacturing (AM) offers great design freedom, the integration of functions into components, new lightweight design concepts and high material efficiency. In aerospace and turbomachinery, this technology is increasingly coming into focus, especially the laser-based powder bed fusion of metals (PBF-LB/M) process. PBF-LB/M is already used for some aerospace components, which are often exposed to high thermal and mechanical loads. Dependent on the component geometry, support structures are required for AM, which then usually have to be removed by machining. One suitable support structure is the use of material with specifically induced porosity. This ensures good heat dissipation and thus homogeneous component properties, high retention forces and short process times in PBF-LB/M. However, the machinability of porous, additively manufactured material has hardly been researched so far. One preliminary investigation of milling porous, additively manufactured Inconel 718, though, showed significantly poorer machinability of the porous material compared to the dense material. To further examine this phenomenon, this paper presents the results of fundamental machinability studies with porous, additively manufactured Inconel 718 in orthogonal cutting. The investigations with tungsten carbide cutting tools on a special fundamental test rig include the analysis of the cutting force, the chip geometry, the chip temperature and the surface quality. The research results provide explanations for the poorer machinability of the porous material and derived approaches for improving the machinability in future studies.

关键词： LPBF PBF-LB/M SLM additive manufacturing AM porous porosity Inconel 718 alloy 718 machining support structure orthogonal cutting

来源：评论

学校读者我要写书评

暂无评论

Surface optimization of dental implants with laser surface texturing and silver coating 22

Surface optimization of dental implants with laser surface t...

引用

22nd International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2022

作者： Uhlmann, E. Brehmer, A. Schneider, Peter Hein, C. Schweitzer, L. Fraunhofer Institute for Production Systems and Design Technology Berlin Germany Institute for Machine Tools and Factory Management Technische Universität Berlin Germany Department of Orthopedics and Orthopedic Surgery University Medicine Greifswald Germany Laser Mikrotechnologie D. Kieburg GmbH James-Franck-Straße 15 Berlin12489 Germany

ISBN: (纸本)9781998999118

The risk of bacterial inflammation at the interface between implant and tissue exists following the implantation of a dental prosthesis. Nearly half of implants are at risk of colonisation by pathogenic bacteria, which is associated with the occurrence of peri-implant mucositis. This disease can develop into peri-implantitis and thereby trigger a severe inflammatory process. The occurrence of peri-implantitis includes different phases. The initial attachment of microorganisms is only possible by pioneer bacteria, such as the gram-positive streptococci. Since the pathogenic cannot form a biofilm unless attached to a surface, the attachment of the pioneer bacteria is crucial for the onset of peri-implantitis. Due to the flexibility and contact free process, laser material processing is used for the surface structuring of several materials. In the biomedical field, laser-based surface texturing enables the production of implants with improved biological reaction surfaces to positively influence protein adsorption and cell adhesion. This paper presents laser texturing and silver coating to reduce initial biofilm formation on Ti6Al4V. The laser processing includes the manufacturing of LIPSS (Laser Induced Periodic Surface Structures), which enables the functionalisation of the surface. Furthermore, the surfaces are coated with silver to act as an inhibitor of biofilm formation. The implant material undergoes an in vitro culture of the microorganism Streptococcus salivarius in order to determine the biofilm formation applying both techniques. The analysis was realized by fluorescence microscopy with the application of 4', 6-diamidino-2-phenylindole (DAPI) on the adhered biofilm. Results show that the surface modification plays a major role in the inhibition of biofilm formation. © European Society for Precision Engineering and Nanotechnology, Conference Proceedings - 22nd International Conference and Exhibition, EUSPEN 2022. All rights reserved.

关键词： Bacteria

来源：评论

学校读者我要写书评

暂无评论

Constructive compensation of the thermal behaviour for industrial robots 13

Constructive compensation of the thermal behaviour for indus...

引用

13th International DAAAM Baltic Conference and 29th International Baltic Conference, BALTMATTRIB 2021

作者： Uhlmann, Eckart Polte, Julian Mohnke, Christian Fraunhofer Institute for Production Systems Design Technology IPK Pascalstraße 8-9 Berlin10587 Germany Institute of Machine Tools and Factory Management Pascalstraße 8-9 Berlin10587 Germany

Industrial robot systems offer a flexible, adaptable basis due to their kinematics and their mobility An influencing variable, which is particularly relevant for processes with long process times, is the thermal heating and the associated thermal drift of the tool center point. The maximum deviation from the actual nominal position can reach up to ΔAPt = 1.5 mm. Currently, there are no procedures and methods established in practice which compensate the effects of thermal drift without expensive calibration measures and system downtime. In these investigations a system was developed which allows the reduction of thermally induced displacement by using controlled heating elements. The aim is to keep the entire robot system at a permanent, balanced temperature level. The heating elements are adapted to the geometry of the respective axis and heat the material to a temperature ϑ close to the steady state. A comparison of the drift through the heating system with the error occurring in normal operation shows that the drift of the heating system is comparable with the drift of normal heating. With the heating mats, a thermally induced error of ΔAPt = 0.234 mm can be generated within t = 20 min. While normal heating requires up to t = 600 min. The achieved error deviation of the drift of the self-heating to the heated variants is with ΔAP = 0.04 mm only minimal. The results can help to reduce the influence of thermal heating and the associated thermal drift of the TCP without using cost-intensive measures with additional hardware and software on external computers for compensating the errors. © 2021 DAAAM International. All rights reserved.

关键词： Industrial robots

来源：评论

学校读者我要写书评

暂无评论

Comparison of Resistive and Optical Strain Measurement for Early Fracture Detection

Comparison of Resistive and Optical Strain Measurement for E...

引用

作者： Carabello, Alina Neupetsch, Constanze Werner, Michael Rotsch, Christian Drossel, Welf-Guntram Zajonz, Dirk Chemnitz University of Technology Adaptronics and Lightweight Design in Production Chemnitz Germany Fraunhofer Institute for Machine Tools and Forming Technology Iwu Chemnitz/ Dresden Germany Zeisigwaldkliniken Bethanien Chemnitz Germany

To increase learning success in surgical training, physical simulators are supplemented by measurement technology to generate and record objective feedback and error detection. An opportunity to detect fractures following hip stem implantation early can be measurement of occurring strains on bone surface. These strains can be determined while using strain gauges, digital image correlation (DIC) or photoelasticity. In this research strain gauges and DIC were compared regarding their suitability as strain measurement tools for use in physical simulators. Therefore a testing method was described to replicate the implantation of a hip stem. Testing devices modelled on a realistic prosthesis were pressed into prepared porcine femora in a two-step procedure with a material testing machine. The local strains occurring on bone surface were determined using an optical measurement system for DIC and strain gauges. The initial fractures in the tested femora are located medial-anterior in most cases (73,6%). With increasing indentation depth of the test device, the strains on bone surface increase. Comparing the local strains determined by DIC and strain gauges consistencies in curves are noticeable. Maximal determined strains before fracturing amount to 0,69% with strain gauges and 0,75% with DIC. In the range of the fracture gap, strain gradients are determined by using DIC. However the detected surfaces are of low quality caused by gaps and motion artefacts. The results show strains on bone surfaces for early fracture detection are measurable with strain gauges and DIC. DIC is assessed as less suitable compared to strain gauges. Furthermore strain gauges have greater level of integration and economic efficiency, so they are preferred the use in surgical training simulators. © 2020 by Walter de Gruyter Berlin/Boston 2020.

关键词： Image correlation

来源：评论

学校读者我要写书评

暂无评论

Metal Foams with Ceramic Inserts for Security Applications 11th

Metal Foams with Ceramic Inserts for Security Applications

引用

11th International Conference on Porous Metals and Metallic Foams, MetFoam 2019

作者： Vogel, René Drebenstedt, Claudia Szyniszewski, Stefan Bittner, Florian Fras, Teresa Blanc, Ludovic Fraunhofer Institute for Machine Tools and Forming Technology IWU Chemnitz Germany University of Surrey Guildford United Kingdom Fraunhofer Institute for Wood Research Wilhelm-Klauditz-Institut WKI Hannover Germany Saint-Louis France

ISBN: (纸本)9783030427979

Protective performance and a low weight of armour plates are the most important objective in security applications. Metallic foams can provide a high level of protection without an extensive mass and were used as a part of various laminated armour systems in the past. Embedding small ceramic parts in metallic foam combines the hardness of ceramics with the flexibility of the lightweight cellular matrix. The material has an extreme cutting resistance against mechanical tools such as angle grinder, drill bits, or other cutting devices. In several testing campaigns, aluminium foams were combined with different internal layouts of stacked or integrated ceramics. The cellular core was foamed directly to steel cover sheets or was bonded to different steel alloy faceplates. In additional tests, blast wave propagation of the metallic foam ceramic composite (MFCC) panels was evaluated. Furthermore, several ballistic tests were performed and compared to state-of-the-art armour materials. It was possible to achieve better performance in this comparison to standard armoured steel at a lower overall weight. © 2020, The Minerals, Metals & Materials Society.

关键词： Metals

来源：评论

学校读者我要写书评

暂无评论

Advancing functional integration through multi-material additive manufacturing: Simulation and experimental validation of a burner nozzle

Advancing functional integration through multi-material addi...

引用

作者： Ringel, Bjoern Zaepfel, Martin Herlan, Florian Horn, Max Schmitt, Matthias Seidel, Christian Fraunhofer Institute for Casting Composite and Processing Technology IGCV Am Technologiezentrum 10 Augsburg86159 Germany Technical University of Munich Institute for Machine Tools and Industrial Management Boltzmannstrasse 15 Garching85748 Germany Department of Applied Sciences and Mechatronics Munich University of Applied Sciences Lothstr. 34 Munich80335 Germany

A combination of simulation and experimental testing is introduced that opens the ability to evaluate the fluid-driven heat exchange of multi-material components. Multi-material laser powder bed fusion is used for processing a nickel-base (Ni) and a copper-base (Cu) alloy in one process fabricating a burner tip component. The multi-material component is compared to its mono-material counterpart made entirely from the Ni-base alloy. A computational fluid dynamics simulation is used to calculate the maximum component temperature differences between both components as-built and heat-treated leading to a theoretical thermal improvement of 36% in the burner tip. Differences between the experimentally achieved thermal improvement of 32% and the theoretical benchmark are discussed by metallographic part analysis. Using the example burner tip component, multi-material process-specific challenges and component design approaches are presented for future applications. © 2022

关键词： Copper alloys

来源：评论

学校读者我要写书评

暂无评论

Reproducibility of modal parameters using different excitation types 26

Reproducibility of modal parameters using different excitati...

引用

26th International Congress on Sound and Vibration, ICSV 2019

作者： Hensel, Eric Knöfel, Björn Fraunhofer Institute for Machine Tools and Forming Technology Dresden Germany

ISBN: (纸本)9781999181000

Experimental acquisition techniques of modal parameters are well-known topics in the dynamic characterization process of steel structures. The objective is to determine the structure's natural vibration properties, which are eigenfrequencies, corresponding mode shapes and damping. Mostly, the experimentally obtained modal parameters are used to verify numerical models, which can be utilized e.g. for overall system vibration simulations. The modal parameters usually were taken from single measurements and thus, few information about the parameter variances are available. In experimental modal analysis, the choice of the boundary condition (e.g. free or grounded support) as well as the corresponding excitation type (e.g. impulse hammer or shaker) may impact the variance of the obtained modal data. The present article focuses on the differences in reproducibility of modal parameters using an impact hammer and a modal shaker, where measurements are carried out under free/free boundary conditions. The test object is a gear wheel, which first eigenfrequency occurs in a frequency range around 4.6 kHz. During the experimental modal analysis, the frequency response functions are obtained up to 20 kHz. Due to the high frequency range, a 3D Scanning Laser Doppler Vibrometer is used to measure the vibrations velocities in all configurations. In a first test setup, statistical variations of a single gear wheel's modal parameters are analyzed and special attention will be payed on the reproducibility of the excitation force using an automated impulse hammer. In a second step, repeated measurements of modal parameters of one gear wheel are presented followed by a comparison of measurements on three identical gear wheels of one lot. Finally, repeating measurements are carried out using a modal shaker for system excitation and the corresponding modal parameters are compared to the results obtained using an impact hammer © Proceedings of the 26th International Congress on Sound and V

关键词： Modal analysis

来源：评论

学校读者我要写书评

暂无评论

VariPath: A Database for Modelling the Variance of Human Pathways in Manual and HRC Processes with Heavy-Duty Robots

VariPath: A Database for Modelling the Variance of Human Pat...

引用

IEEE International Conference on Robotics and Automation (ICRA)

作者： Mohamad Bdiwi Ann-Kathrin Harsch Paul Reindel Matthias Putz Fraunhofer Institute for Machine Tools and Forming Technology IWU Chemnitz

ISBN: (数字)9781728173955

ISBN: (纸本)9781728173962

Unlike robots, humans do not have constant movements. Their pathways are individually changeable and influenced by circumstances. This paper presents a method to investigate human pathway variations in a real study. In systematically selected tasks, human pathways are examined for 100 participants in manual and human-robot collaboration (HRC) scenarios. As a result, the variations of pathways are presented depending on various features: e.g. in nearly all cases the variance of women's walking pathways is smaller than that of men. VariPath database can be used in any planning process of manual or HRC scenarios to ensure safety and efficiency.

关键词： Legged locomotion Service robots Task analysis Planning Atmospheric measurements Particle measurements

来源：评论

学校读者我要写书评

暂无评论

New VDI guideline 2248 - An overview

New VDI guideline 2248 - An overview

引用

International Conference on Shape Memory and Superelastic Technologies 2019, SMST 2019

作者： Böhm, Andrea Fraunhofer Institute for Machine Tools and Forming Technology Dresden Germany

来源：评论

学校读者我要写书评

暂无评论

Digital innovation hubs for robotics - TRINITY approach for distributing knowledge via modular use case demonstrations 8

Digital innovation hubs for robotics - TRINITY approach for ...

引用

8th CIRP Conference of Assembly technology and Systems, CATS 2020

作者： Lanz, Minna Reimann, Jan Ude, Aleš Kousi, Niki Pieters, Roel Dianatfar, Morteza Makris, Sotiris Tampere University Tampere Finland Fraunhofer Institute for Machine Tools and Forming Technology IWU Chemnitz Germany Jožef Stefan Institute Ljubljana Slovenia University of Patras Patras Greece

Robots are no longer stand-alone systems on the factory floor. The demand for industrial robots (market) is anticipated to be growing to 65 billion euros by the year 2023. Within all areas of robotics, the demand for collaborative and more flexible systems is rising as well. The level of desired collaboration and increased flexibility will only be reached if the systems are developed as a whole, e.g. perception, reasoning and physical manipulation. The rising need for collaborative robots in the automation industry is acting as a driver for this market and is expected to serve as a market opportunity for future growth. However, at the same time especially smaller companies have difficulties to formulate a concrete vision and strategies for the uptake of robotics, finding skilled workforce to develop and deploy the robot systems and/or work in the manufacturing industry. A number of Digital Innovation Hubs (DIHs) have been developed to enhance the knowledge and technology transfer from laboratories to factory floors, mitigating the skills gap and supporting the formulation of innovation ecosystems with the specific focus on small and medium-sized companies around Europe. The main aim of this paper is to introduce the concept and approach taken in H2020 TRINITY-project that aims to develop a Robotics Innovation Hub focused on Agile Production. The paper will introduce the concept and technical approach of the project, and discusses the preliminary results, challenges and opportunities of these kind of DIHs. © 2020 The Author(s).

关键词： Industrial robots

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：