Buch, Englisch, Band 14, 204 Seiten, Format (B × H): 148 mm x 210 mm, Gewicht: 300 g
Scripts Precision and Microproduction Engineering, Band 14
Buch, Englisch, Band 14, 204 Seiten, Format (B × H): 148 mm x 210 mm, Gewicht: 300 g
Reihe: Scripts Precision and Microproduction Engineering
ISBN: 978-3-95735-125-8
Verlag: Wissenschaftliche Scripten
Gegenstand dieser Arbeit ist die Bearbeitung von Nitinol für medizinische Anwendungen mittels Mikrofunkenerosion (Mikro-EDM) ermittelt. Dabei wurden die generelle Möglichkeit und das Potential dieser Bearbeitung untersucht. Dazu gehört die Analyse von Prozesseffekten auf die Oberflächeneigenschaften, auf das Verhalten der martensitischen Phasenumwandlung sowie auf die mechanischen Eigenschaften von Nitinol. Auf Grund der Eigenschaften Formgedächtniseffekt und Superelastizit¨at wird Nitinol häufig für medizinische Anwendungen eingesetzt. Diese Arbeit gibt einen Einblick in die Auswirkungen des Bearbeitungsprozesses auf diese beiden speziellen Eigenschaften. Es konnte gezeigt werden, dass Mikro-EDM das Potenzial hat, thermische Effekte zu implementieren, die das Verhalten der Nitinolphasenumwandlung verändern können. Dazu gehören die Reduzierung der Hysterese sowie das Auftreten eines Dreispitzenphänomens bei der umgekehrten endothermen Phasenumwandlung beim Erwärmen. Als Hauptursache für dieses Dreispitzenverhalten konnte das Auftreten von Lichtbögen ermittelt werden. Darüber hinaus konnte gezeigt werden, dass es durch systematische Variation ausgewählter Prozessparameter möglich ist, Nitinol mit vernachlässigbaren thermischen Einflüssen zu bearbeiten. Unter der Voraussetzung einer Lichtbogen freien Bearbeitung war es zudem möglich, eine Erhöhung der Entladungsenergie zu erreichen, ohne wesentlich das Umwandlungsverhalten des Materials zu beeinflussen. Dies erlaubt die Abtragrate, die Elektrodenverschleißrate und die Oberflächenqualität zu optimieren und gleichzeitig unerwünschte Prozesseffekte zu minimieren.
Abstract
Within the scope of this work, micro-electrical discharge machining (micro-EDM) of medical-grade nitinol has been undertaken and examined for suitability and capability. This includes analysing process effects on nitinol’s surface characteristics, martensitic phase transformation behaviour as well as mechanical properties. Consequently, an insight on
how the process affects nitinol’s shape memory and superelasticity, two unique properties that make nitinol a key application material in the medical field, is given. It can be shown that micro-EDM has the potential to impart thermal effects that alter nitinol’s phase transformation behaviour. These include reducing hysteresis as well as resulting in the occurrence of a three-peak phenomenon during the reverse endothermic phase transformation on heating. It was also possible to establish arcing as the main cause of this three-peak behaviour. Moreover, it can be shown that by carefully controlling vital micro-EDM machining parameters, it is not only possible to machine nitinol parts with negligible thermal-related influences, but also that, as long as arcing is avoided, an increase in discharge energy does not significantly affect the material’s phase transformation behaviour. This can therefore aid in optimising the material removal rate, tool wear rate and surface quality, while minimising unwanted process effects.
Autoren/Hrsg.
Weitere Infos & Material
Fundamentals
Surface modification by cathodic hydrogenation with electrochemical jet
Zhao, Y.; Zhang, G.; Xue, J.; Kakudo, S.; Kunieda, M.
Features of the discharge between a metal anode and a hollow current supply
Popov, A. I.; Novikov, V. I.; Radkevich, M. M.; Novoselov, M. V.; Zakharov, S. V.; Teplukhin, V. G.
Detection of hydrogen in cathode tool during pulse electrochemical machining
Ghasemiansafaei, M.; Güner, M.; Schäfer, F.; Zeiner, M.; Bähre, D.
Formation of Flow-Grooves during Electrochemical Machining
Rommes, B.; Klink, A.; Herrig, T.; Vorspohl, J.; Ehle, L.; Bergs, T.
Processing / Process Control
Investigation of Single Pulse Smoothing Characteristics during PECM
Klink A.; Rommes, B.; Heidemanns, L.; Herrig, T.
Process source analysis of the regulation parameters for simultaneous hole widening
Schulze, H.-P.; Kröning, O.; Herzig, M.
New potentials for precise ECM achieved by Orbiting-kinematics
Schoesau, R.; Böttcher, F.; Petzold, T.; Rentzsch, H.; Edelmann, J.
Materials
Electrochemical machining of molybdenum
Schneider, M.; Simunkova, L.; Michaelis, A.; Hoogsteen, W.
Experimental study of electrochemical machining of selective laser melted Inconel 718
Herter, F.; Ernst, A.; Bergmann, A.; Bähre, D.
Statistical Analysis of Jet Electrochemical Post-processing of Additively Manufactured Workpieces
Yahyavi Zanjani, M.; Martin, A.; Zinecker, M.; Schubert, A.
Pulsed electrochemical machining of 1.2709 additive manufactured steel
Schröder, S.; Petzold, T.; Martin, A.; Schubert, A.
Simulation and Modelling
Multiphysics simulation enabled ‘virtual sensing’ approach for monitoring the parameters in the interelectrode gap during tool-based hybrid laser-electrochemical micromachining
Saxena, K. K.; Wu, M.; Chen, X.; Qian, J.; Reynaerts, D.
Transient Removal Simulation of the Jet Electrochemical Machining Process based on a Finite Area Element Grid
Wienand, T.; Meichsner, G.; Hackert-Oschätzchen, M.
Order Reduction of Simulation Models for the Precise Electrochemical Machining of Centrifugal Impellers
Loebel, S.; Petzold, T.; Steinert, P.; Zinecker, M.; Schubert, A.
Applications
Antibacterial surfaces textured by electrolyte jet machining
Jing, H.; Kunieda, M.; Romoli, L.
Precise processing of multiple actuator elements by pulsed electrochemical machining
Schneider, J.; Petzold, T.; Uhlmann, M.; Boehm, A.; Edelmann, J.; Martin, A.; Schubert, A.
Pulse Electrochemical Machining (PECM) of microstructured functional surfaces
Hall, T.; Ernst, A.; Durneata, D.; Natter, H.; Saumer, M.; Bähre, D.
Process design for the precise electrochemical machining of internal blind hole gears
Schaarschmidt, I.; Steinert, P.; Zinecker, M.; Schubert, A.
Hybrid EC-Processes
Electrolytic Plasma Micropatterning of Plasma Sprayed Ceramic Coatings
Laugel, N.; Bogachov, D.; Yerokhin, A.
Hybrid Electrochemical Machining Processes
Ruszaj, A.; Cygnar, M.; Furyk-Grabowska, K.; Grabowski, M.
Workpiece temperature during plasma-electrolytic polishing
Zeidler, H.; Böttger-Hiller, F.; Penzel, M.; Böttger, T.
Correlation between Current Density and Ablation Rate of Jet-PeP
Quitzke, S.; Martin, A.; Schubert, A.
Electrolyte flow in Plasma-electrolytic Polishing
Zeidler, H.; Böttger-Hiller, F.; Penzel, M.; Böttger, T.; Leihkauf, H.
Authors Index
Foreword from the editor
The book series titled, “Precision and Microproduction Engineering” presents, in an irregular sequence, results of research related to recent developments in the sectors of Precision Manufacturing and Surface Technology. These results are based on the research of the Professorship “Micromanufacturing Technology” of Chemnitz University of Technology as well as the“Functional Surfaces and Microsystem Manufacturing”department of the Fraunhofer Institute for Machine Tools and Forming Technology, both of which form the “Competence Center Micromanufacturing and Surface Technologies - KoMOT”. This thirteenth volume of the series is dedicated to the topic of Electrical Discharge Machining (EDM). EDM is an important manufacturing technology especially when it comes to the need for machining very hard, or hard to machine electrically conducting materials, a need which is often combined with the demand for achieving tiny and/or precise features. In this volume, the focus is set on micromachining a nickel-titanium based shape memory alloy. The dissertation submitted by James Wamai Mwangi aims for the analysis of influences of micro-electrical discharge machining on shape memory alloys, specifically the nickeltitanium alloy usually referred to as Nitinol. The presented work considers the influence of material and surface property changes, that are inflicted by the machining process, on the mechanical properties as well as the phase transformation behavior of Nitinol. Moreover, the influence of micro-EDM’s thermal impact on the material is investigated. In this regard, different machining conditions were considered and the influence of the micro-EDM process was compared with influences related to other suitable nitinol machining processes. This work contains challenging scientific tasks and includes experimental as well as analytical work in the field of engineering sciences. The results show the impact of the micro-EDM machining process, mainly of the thermal influences, on the properties of Nitinol, the roughness and the chemical composition of the surface layer and the stress-strain-behavior of the machined material. In addition, investigations are done to establish how the thermal impact of the machining process leads to an altering of the phase transformation temperatures and the thermal hysteresis of the material.Generally speaking, this thesis supports the systematic design of appropriate micro-EDM processes for machining of Nitinol in the context of medical and microstructured applications.
Prof. Dr.-Ing. Andreas Schubert
Chemnitz, June 2019
