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Ultrasonic Vibration assisted Silver Integration by Powder Mixed EDM for Antibacterial Surfaces

Procedia CIRP 2024年 123卷 410-415页

作者： Viet D. Bui André Martin Thomas Berger Karsten Harnisch Joachim Döring Jessica Bertrand Andreas Schubert Chemnitz University of Technology Professorship Micromanufacturing Technology Reichenhainer Str. 70 09126 Chemnitz Germany Otto-von-Guericke University Magdeburg Institute of Materials and Joining Technology Universitätsplatz 2 39106 Magdeburg Germany Otto-von-Guericke University Magdeburg Department of Orthopaedic Surgery Leipziger Str. 44 39120 Magdeburg Germany Fraunhofer Institute for Machine Tools and Forming Technology Reichenhainer Str. 88 09126 Chemnitz Germany

Powder mixed electrical discharge machining (PMEDM) with silver nano-powder has demonstrated its potential capability in antibacterial surface modification. Analyses in the cross-sectional layer showed that silver was mainly integrated near the topmost surface layer, and its content is reduced within the layer towards the substrate. However, to achieve a long-term antibacterial efficacy, silver needs to be deeply integrated in the modified layer. Previous studies indicated that ultrasonic vibration (UV) assisted PMEDM can homogenize the silver content in the deposited layer. In this study, the effect of UV on the silver distribution within the modified layer is investigated. Ti6Al4V workpieces were stimulated by UV with a frequency of 22.3 kHz and an amplitude of 2.5 µm. Hydrocarbon-based dielectric fluid, mixed with silver nano-powder with concentrations up to 15 g/L, were internally flushed through a hollow tool with a pressure of 4 bar. PMEDM without UV was investigated for comparison. The layer thickness, micro-cracks and the cross-sectional distribution of deposited silver were analysed by confocal microscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Results indicate that applying UV leads to the highest silver content in the middle region of the layer, a significant decrease of micro-cracks and a slight reduction of the layer thickness.

关键词： powder mixed EDM ultrasonic vibration silver distribution modified layer antibacterial effect

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Ethanol Exposure Duration Effects on Soft Tissue Biomechanics

SSRN

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SSRN 2024年

作者： Werner, Michael Drossel, Welf-Guntram Löffler, Sabine Hammer, Niels Fraunhofer Institute for Machine Tools and Forming Technology Dresden Germany Institute of Anatomy University of Leipzig Leipzig Germany Division of Macroscopic and Clinical Anatomy Gottfried Schatz Research Center Medical University of Graz Graz Austria Department of Orthopedic and Trauma Surgery University of Leipzig Leipzig Germany Department of Anatomy University of Otago Dunedin New Zealand

When conducting biomechanical testing or clinical training using embalmed human soft tissues, it is essential to understand their impact on biomechanical properties and their time dependence. Previous studies have investigated this influence, but specific variations over different embalming durations have not been thoroughly addressed to ***-seven human iliotibial band specimens were obtained from nine donors. All specimens were embalmed in ethanol-glycerin for varying durations: one day, eight days, and fourteen days. Prior to the mechanical trials, the specimens underwent osmotic water adjustment, tapering and standardized clamping. Uniaxial tensile tests were conducted to determine elastic modulus, ultimate tensile strength, and ultimate strain. Surface strain measurements were performed using a digital image correlation ***-glycerin embalming of soft tissues significantly affects ultimate strain after one day of submersion time, elastic modulus after eight days, and the ultimate tensile strength after fourteen days. For applications requiring consistent and reliable material properties reflecting a (supra-)vital state, caution is advised against using embalmed tissues even following short submersion durations in ethanol-glycerin. © 2024, The Authors. All rights reserved.

关键词： Tensile strength

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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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Modular instrument for the minimally invasive surgery with SMA actuation and control

Modular instrument for the minimally invasive surgery with S...

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

作者： Braun, Dennis Weik, David Eisner, Sophia Werner, Michael Fraunhofer Institute for Machine Tools and Forming Technology IWU Department of Medical Engineering Dresden Germany

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Automated continuous fabrication of load-path adapted thermoplastic fiber prepregs 18

Automated continuous fabrication of load-path adapted thermo...

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18th European Conference on Composite Materials, ECCM 2018

作者： Gabriel, Felix Nebel, Daniel Fürst, Alexander TU Braunschweig Institute of Machine Tools and Production Technology Langer Kamp 19b Braunschweig38106 Germany Fraunhofer Institute for Machine Tools and Forming Technology STEX Department Fraunhofer Project Center Wolfsburg Hermann-Münch-Straße 2 Wolfsburg38440 Germany TU Braunschweig Institute for Engineering Design Langer Kamp 8 Braunschweig38106 Germany

ISBN: (纸本)9781510896932

Due to the lack of suitable production processes, most up-to-date composite components show a rather simple shell design with constant laminate build-up. Such designs are also known as "black metal" and lead to high costs and incomplete material utilization. In contrast, a special load-path adapted design with a high utilization of deployed materials can increase the lightweight degree and reduce costs at the same time. This paper proposes a first practical approach to provide the automated continuous fabrication of load-path adapted thermoplastic fiber prepregs in a calendaring process. For the complete impregnation of the textile, additional matrix is added in powder form in order to ensure a homogenous fiber volume ratio. An adjustable powder application system is proposed, which can be directly integrated into the calender and is able to follow the load-path adapted design routes provided as continuous semifinished material. A sensor-driven control strategy for the application module is presented in order to cope with the challenge of synchronization of the conveyed semifinished textile with the positioning and powder dosing mechanisms of the application system. © CCM 2020 - 18th European Conference on Composite Materials. All rights reserved.

关键词： Fabrication

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Inductive Sintering Module for Improved Multi-Die Attach in the Field of Power Packaging

Inductive Sintering Module for Improved Multi-Die Attach in ...

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IEEE CPMT Symposium Japan

作者： Christian Hofmann Patrick Rochala Martin Kroll Sushant Panhale Mario Baum Harald Kuhn Kiyoshi Oi Masaki Sanada Kei Murayama Department System Packaging Fraunhofer Institute for Electronic Nano Systems ENAS Chemnitz Germany Professorship for Forming and Joining Institute for Machine Tools and Production Processes (IWP) Chemnitz University of Technology Chemnitz Germany Department Systems Engineering Fraunhofer Institute for Electronic Nano Systems ENAS Chemnitz Germany Fraunhofer Institute for Electronic Nano Systems ENAS Chemnitz Germany Process Development Dept. SHINKO ELECTRIC INDUSTRIES CO. LTD. Nagano Japan

This work presents a heating technology for multi-die attach based on inductive silver sintering. Thus, the heat for the sintering reaction is confined locally to the bond region, avoiding heating of the entire power ...

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Improvements to a method for determining leg length following total hip arthroplasty

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Journal of Medical Engineering and technology 2020年第2期44卷 69-75页

作者： Wendler, Toni Heilemann, Martin Grunert, Ronny Möbius, Robert Schmidt, Michael Schleifenbaum, Stefan Prietzel, Torsten Centre for Research on Muscoskeletal Systems Leipzig University Leipzig Germany Faculty of Medicine Institute of Anatomy Leipzig University Leipzig Germany Department of Orthopaedic Trauma and Plastic Surgery Leipzig University Leipzig Germany Fraunhofer Institute for Machine Tools and Forming Technology Dresden Germany Department of Neurosurgery Leipzig University Leipzig Germany Department of Orthopaedic Trauma and Plastic Surgery Zeisigwaldkliniken Bethanien Chemnitz Chemnitz Germany

Discrepancy in leg length does frequently occur as a side effect of total hip arthroplasty and may lead to reduced patient satisfaction as well as injury in the sequalae. It is consequently important to reduce leg length discrepancy where-ever technically possible. This may be achieved by recording precise intraoperative measurements and using different sized implanted components. The aim of the given study was to improve the accuracy of a previously validated optic measurement system (OMS) to reduce leg length discrepancy. This pre-existing OMS was first trialled and based on these preliminary findings developed further. Using this improved system, measurements were taken in models and cadavers. Inter observer reliability of the improved OMS was assessed. The system is introduced in the given technical feasibility study. Its accuracy was greater in the model setup (swivel joint: 772.7 ± 1.5 mm;ball joint: 770.0 ± 3.7 mm;reference: 772 mm) compared to the trial using cadaveric tissues (588.8 ± 5.7 mm;reference: 586 mm). Results of two examiners were similar. The third one measured significantly shorter values (p=.011). The results of the measurements with the OMS indicate that a significant increase in accuracy (p = 2.076×10−6) has been achieved compared to the previously reported system, however, a further improvement to measurement accuracy is necessary for this to be applied clinically. © 2020, © 2020 Informa UK Limited, trading as Taylor & Francis Group.

关键词： Arthroplasty

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Haptic feedback is more important than VR experience for the user experience assessment of in-car human machine interfaces 31st

Haptic feedback is more important than VR experience for the...

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31st CIRP Design Conference 2021, CIRP Design 2021

作者： Schölkopf, Lasse Lorenz, Mario Stamer, Mareike Albrecht, Lina Klimant, Philipp Hammer, Niels Tümler, Johannes Volkswagen AG Berliner Ring 2 Wolfsburg38436 Germany Professorship for Production Systems and Processes Chemnitz University of Technology Reichenhainer Straße 70 Chemnitz09126 Germany Department of Orthopedics Trauma and Plastic Surgery University Hospital Leipzig Liebigstraße 20 Leipzig04103 Germany Department of Macroscopic and Clinical Anatomy Medical University of Graz Harrachgasse 21 Graz8010 Austria Fraunhofer Institute for Machine Tools and Forming Technology IWU Nöthnitzer Straße 44 Dresden01187 Germany Professur Ingenieurinformatik Anhalt University of Applied Sciences Bernburger Str. 55 Köthen06366 Germany

The user experience (UX) of a product is important for a customer's decision, especially in the automotive sector. In recent years, a frontloading of UX assessments from physical prototypes to virtual prototypes has occurred. Nevertheless, there are clear indications that established UX assessments methods cannot simply be transferred 1-to-1 from real to virtual evaluation setups as results get biased. For the UX assessment of an in-car human machine interface (HMI) the haptic properties of the knobs and buttons are just as important as their visual features. Therefore, it is mandatory to also simulate the haptic behavior of the in-car HMI in virtual reality (VR) assessment scenarios. However, accurately simulating this haptic behavior adds considerable costs and effort, diminishing the beneficial effects of VR UX assessments. Due to confidentiality reasons the volunteering participants of VR UX studies in the automotive sectors are typically employees with a varying degrees of VR experience. It is unknown if this gap in VR experience biases the results of UX assessments in VR. This paper presents a UX assessment study of an in-car HMI in VR in comparison to reality. From a practitioners viewpoint two research question are investigated: (1) How much is the UX assessment impaired by missing haptic simulation? (2) Does VR experience influence UX assessment ratings in VR? The results show that missing haptic feedback severely diminishes UX ratings, leaving no doubt that meaningful UX assessments in VR can only be performed when haptic is included. This means that more effort has to be put into earlier VR assessments severely reducing its benefits compared to UX assessments with physical prototypes. However, the VR experience of the participants only has a slight effect on the UX assessment results. © 2021 Elsevier B.V.. All rights reserved.

关键词： Virtual reality

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THE BIOMECHANICAL STABILITY OF A NOVEL BIOABSORBABLE MAGNESIUM ALLOY (ZX00:Mg–Zn–Ca) BONE ANCHOR FOR ROTATOR CUFF REPAIRS: A HUMAN EX VIVO STUDY

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Journal of Musculoskeletal Research 2025年第1期28卷

作者： Kinsky, Rudolf Maximilian Schleifenbaum, Stefan Honea, Maxim Siegert, Paul Hammer, Niels Fischerauer, Stefan Franz Weinberg, Annelie Wurnig, Christian Sanatorium Hera Loeblichgasse 14 Vienna 1090 Austria Department of Orthopedic Trauma and Plastic Surgery Semmelweisstraße 14 Raum-1322 (Sockelgeschoss) Leipzig D-04103 Germany Institute of Materials Science Joining and Forming Technical University of Graz Rechbauerstraße 12 Graz 8010 Austria Orthopaedic Hospital Speising 109 Speisingerstrasse Vienna 1130 Austria Division of Macroscopic and Clinical Anatomy Gottfried Schatz Research Center Medical University of Graz Auenbruggerplatz 25 Graz 8036 Austria Fraunhofer Institute for Machine Tools and Forming Technology Nöthnitzer Str. 44 Dresden 01187 Germany Department of Orthopaedic Trauma and Plastic Surgery University Clinics of Leipzig Liebigstr. 27 Leipzig 04109 Germany University Clinic f. Orthopaedics und Traumatology Medical University Graz Auenbruggerplatz 5 Graz 8036 Austria Musculo-Skeletal Research Unit for Biomaterials Department of Orthopaedics Trauma Medical University of Graz Auenbruggerplatz 5 Graz 8036 Austria

Introduction: The purpose of this study was to ascertain the primary ex vivo biomechanical stability of a novel bioabsorbable magnesium alloy (ZX00: Mg–Zn–Ca) bone anchor in human cadaveric proximal humeri, indicated in the reconstruction of the rotator cuff. Methods: Twenty human Thiel-embalmed cadaveric humeri were prepared and freed from soft tissue. One ∅5.7 × 20.5-mm ZX00 anchor and one ∅5.5 mm × 16.3 mm Arthrex Titanium FT Corkscrew (ATC) control anchor were inserted into the footprint of the supraspinatus tendon, 15 mm apart. The humeri were mounted onto a material testing machine and following a 40 N preload, cyclic loading was performed over 400 cycles. If the construct remained intact, ultimate load to failure (ULTF) was measured using an increasing axial load of 1 mm/s, ULTF and mode of failure were recorded. Results: No difference was found in the ability to withstand cyclic loading, mode or load-to-failure strengths between ZX00 and control anchors. The maximum tractional force loaded for the ZX00 anchors had a median of 257.4 N (range 165.3–328.2). The corresponding value for the ATC anchors averaged 239.9 N (range 118.9–306.7). Conclusion: ZX00 alloy anchors appear to provide adequate initial biomechanical stability when compared to an industry-standard control in a cadaveric rotator cuff repair model. © 2025 The Author(s)

关键词： Absorbable implants Alloys Magnesium Rotator cuff tear Arthropathy Shoulder injuries

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Revisiting machinability assessment: Towards total machining performance

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CIRP Annals 2025年

作者： I.S. Jawahir Helmi Attia Martin Dix Hassan Ghadbeigi Zhirong Liao Julius Schoop Alborz Shokrani Institute for Sustainable Manufacturing (ISM) University of Kentucky Lexington KY USA Mechanical Engineering Department McGill University/Aerospace Manufacturing Technology Centre National Research Council Canada Montreal QC Canada Fraunhofer Institute for Machine Tools and Forming Technology IWU University of Technology Chemnitz Chemnitz Germany School of Mechanical Aerospace and Civil Engineering University of Sheffield Sheffield United Kingdom Faculty of Engineering University of Nottingham Nottingham United Kingdom Department of Mechanical Engineering University of Bath Bath United Kingdom

The term “machinability”, introduced over hundred years ago, is vague and cannot fully describe the performance of machining systems. Machinability databases established over many decades are outdated: missing recent advances, e.g., cutting tool grades, geometry, coatings, and cutting fluids effects. This keynote paper summarizes findings of a CIRP-sponsored three-year collaborative study in five interrelated topics. The paper presents a critical review of the state-of-the-art on these topics, the results of two major round robin tests, three industry-based case studies, and a novel predictive system of machining performance, utilizing advanced deep learning methods. Outlook and future directions are also presented.

关键词： Drills

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