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Hybrid approach to evaluate surface integrity based on grinding power and Barkhausen noise

Procedia CIRP 2022年 108卷 489-494页

作者： Jonas Heinzel Rahel Jedamski Maximilian Rößler Bernhard Karpuschewski Jérémy Epp Martin Dix MAPEX Center for Materials and Processes University of Bremen Bibliothekstr. 1 28359 Bremen Leibniz Institute for Materials Engineering IWT Badgasteiner Str. 3 Bremen 28359 Germany Fraunhofer Institute for Machine Tools and Forming Technology Reichenhainer Straße 88 09126 Chemnitz Germany

In this paper the potential of a reliable characterization of surface and subsurface properties is presented by measurement of process forces for determining the specific grinding power Pc” and the micromagnetic Barkhausen noise in cylindrical grinding trials. Therefore different dressing conditions by grinding with conventional wheel with varying process parameters are investigated. It is shown that an identified lower thermal limit in a Pc” - ∆t -diagram (contact time ∆t ) to prevent tempering zones in the ground surface and subsurface area of case hardened steel is applicable even if the condition of the grinding wheel is intentionally influenced by dressing. Finally a soft sensor concept for the use of the specific grinding power and in perspective also the use of the Barkhausen noise for process control is derived.

关键词： grinding burn detection surface integrity process control

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Comparison of Resistive and Optical Strain Measurement for Early Fracture Detection

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

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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

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Local Microscopic and Integral Macroscopic Analysis of Magnetic Pulse Welds and Deformations for Dissimilar Metal Joints 13th

Local Microscopic and Integral Macroscopic Analysis of Magne...

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13th International Conference on the technology of Plasticity, ICTP 2021

作者： Huberth, Frank Ragupathi, Balaji Scheffler, Christian Psyk, Verena Preußner, Johannes Fraunhofer Institute for Mechanics of Materials IWM Woehlerstrasse 11 Freiburg79108 Germany Department of Sustainable Systems Engineering EFM University of Freiburg Faculty of Engineering Emmy-Noether-Str. 2 Solar Info Center 4 Freiburg79110 Germany Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Strasse 88 Chemnitz09126 Germany

ISBN: (纸本)9783030753801

Magnetic pulse technology is used for high-speed forming as well as for joining. Joining by magnetic pulse welding (MPW) is the combination of high-speed forming, impact, and a resulting weld in the collision zone of the accelerated flyer and the impacted target. This MPW process allows the welding of dissimilar metals, like aluminum and steel for lightweight construction or aluminum and copper for E-mobility applications. Investigations showed up scattering in binding strength and failure for comparable welds. The effects leading to the bond formation and the reasons for the quality variation are not fully understood until now. For further understanding, a combined experimental investigation of integral and local mechanical weld properties supported by simulations and microstructure analysis was performed considering dissimilar metal joints of aluminum EN AW1050 H14/24 and copper Cu DHP R240 for different configurations and impact energies. Lap shear tests served for quantifying integral mechanical properties, while local mechanical properties were determined by microtensile tests on samples prepared in the thickness direction of the welded metal sheets and microstructural analysis. These local microscopic testing and analysis results provide information about the weld strength distribution. These investigations give new hints on the bond-forming mechanisms and local process depending on material effects. © 2021, The Minerals, Metals & Materials Society.

关键词： Welds

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Synergy Analysis and verification of connected Cyber Physical Systems using virtual commissioning

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Procedia CIRP 2021年 99卷 639-644页

作者： Christoph Allmacher Anna Seiderer Philipp Klimant Michael Kuhl Institute for Machine Tools and Production Processes Chemnitz University of Technology Reichenhainer Str. 70 09126 Chemnitz Germany Mittweida University of Applied Sciences Technikumplatz 17 09648 Mittweida Germany Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Str. 88 09126 Chemnitz Germany

The design of cyber physical systems in today’s production and intralogistics is influenced by the increasing availability and exchange of data. On the one hand, synergies between connected systems can be used to develop lightweight applications by sharing and reusing data. On the other hand, the possible combinations between these systems increase the complexity and design options. This paper presents a method to structure possible design options systematically and proposes virtual commissioning as solution for their analysis and verification to enable early design decisions. The method is demonstrated using an automated guided vehicle combined with a tactile warning device.

关键词： Virtual commissioning Automated guided vehicle Tactile warning device

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Usage-based leasing of complex manufacturing systems: A method to transform current ownership-based into pay-per-use business models

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Procedia CIRP 2022年 107卷 1238-1244页

作者： Mohaned Alaluss Chris Drechsler Robin Kurth Anton Mauersberger Steffen Ihlenfeldt Michael Marré Rainer Labs Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Strafβ 88 09126 Chemnitz Germany Institute of Mechatronic Engineering Technische Universität Dresden Helmholtzstr. 7a 01069 Dresden Germany South Westphalia University of Applied Sciences Frauenstuhlweg 31 58644 Iserlohn Germany

Manufacturing technology with its cost- and resource-intensive manufacturing machines like machine tools, whose amortization often takes several years, is characterized by a high degree of individualization. Here, the need for increasingly complex as well as individualized products leads to the demand for high flexibility and resilience in complex manufacturing systems. The increasing uncertainty and volatility in the markets pose high economic risks for machine operators with ownership-based business models to enter new technologies. Consequently, this restrains the innovative and creative power of manufacturing companies. Although leasing models exist in various industry sectors like printing industry or compressed air supply, their implementation is still challenging due to the high degree of complexity regarding machine system, process, and services of the leasing product. In this paper, a novel method, with increased consideration of technical-technological aspects, to transform current ownership-based into usage-based business models like pay-per-use, is proposed. The resulting method also considers the pay-per-use readiness through an initial assessment of the existing manufacturing system.

关键词： perfomance-based contracting pay-per-use method business models manufacturing machines machine tools industry 4.0 agile production

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Reproducibility of modal parameters using different excitation types 26

Reproducibility of modal parameters using different excitati...

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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

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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...

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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

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machine learning for material characterization with an application for predicting mechanical properties

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GAMM Mitteilungen 2021年第1期44卷 e202100003-e202100003页

作者： Stoll, Anke Benner, Peter Data-Mining and Machine Learning Fraunhofer Institute for Machine Tools and Forming Technology IWU Chemnitz Germany Computational Methods in Systems and Control Theory The Max Planck Institute for Dynamics of Complex Technical Systems Magdeburg Germany

Currently, the growth of material data from experiments and simulations is expanding beyond processable amounts. This makes the development of new data-driven methods for the discovery of patterns among multiple lengthscales and time-scales and structure-property relationships essential. These data-driven approaches show enormous promise within materials science. The following review covers machine learning (ML) applications for metallic material characterization. Many parameters associated with the processing and the structure of materials affect the properties and the performance of manufactured components. Thus, this study is an attempt to investigate the usefulness of ML methods for material property prediction. Material characteristics such as strength, toughness, hardness, brittleness, or ductility are relevant to categorize a material or component according to their quality. In industry, material tests like tensile tests, compression tests, or creep tests are often time consuming and expensive to perform. Therefore, the application of ML approaches is considered helpful for an easier generation of material property information. This study also gives an application of ML methods on small punch test (SPT) data for the determination of the property ultimate tensile strength for various materials. A strong correlation between SPT data and tensile test data was found which ultimately allows to replace more costly tests by simple and fast tests in combination with ML. © 2021 The Authors. GAMM - Mitteilungen published by Wiley-VCH GmbH.

关键词： machine learning

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New VDI guideline 2248 - An overview

New VDI guideline 2248 - An overview

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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

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An investigation of abrasive waterjet machining of cubic boron nitride (CBN) with a softer abrasive material

An investigation of abrasive waterjet machining of cubic bor...

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20th CIRP Conference on Electro Physical and Chemical Machining, ISEM 2020

作者： Morczinek, F. Putz, M. Chemnitz University of Technology Reichenhainer Str. 70 Chemnitz09126 Germany Fraunhofer Institute for Machine Tools an Forming Technology IWU Reichenhainer Str. 88 Chemnitz09126 Germany

For an effective machining of high-performance materials, high-strength cutting materials, e.g. cubic boron nitride (CBN), with high resistance to any kind of wear are used. However, these materials must also be able to be machined in order to produce geometric elements such as chip breakers or chip grooves. According to the current state of the art, grinding and laser beam technology are used for this purpose. In this paper, an attempt was made to use the erosive removal mechanism of abrasive water jet technology to cut a harder material with a softer abrasive. Within the framework of a full factorial test plan, the removal rate, the macroscopic kerf geometry on CBN were investigated by means of abrasive water jet machining. It could be proven that it is possible to remove a harder material with a softer abrasive by means of abrasive water jet technology. © 2020 The Authors. Published by Elsevier B.V.

关键词： Abrasion

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