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Frederik Zanger

Dr.-Ing. Frederik Zanger

Oberingenieur
Bereich: Fertigungs- und Werkstofftechnik
Sprechstunden: nach Vereinbarung
Raum: 103, Geb. 10.92
Tel.: +49 721 608-42450
Fax: +49 721 608-45004
Frederik ZangerOzx9∂kit edu

Campus Süd



Oberingenieur Dr.-Ing. Frederik Zanger

Forschungs- und Arbeitsgebiete:

Prozesse Surface Engineering

Fertigungsprozesse

  • Zerspanung
  • Mikrobearbeitung
  • Generative Fertigung
  • Mechanische Oberflächenbehandlung
     
     

Prozessführung und -simulation

  • Kühlschmierkonzepte
  • In-Prozess-Kontrolle
  • Simulation von Prozessen und -ketten
  • Prozess-Werkstück-Maschine-Interaktion

Bauteilrandzonen

  • Topographie
  • Gefüge
  • Eigenspannungen
  • Verfestigung
  • Simulation der Bauteilzustände
     

Bauteilverhalten

  • Schwingende Beanspruchung
  • Tribologische Beanspruchung
  • Simulation des Bauteilverhaltens


Allgemeine Aufgaben:

 

Dissertation:

Segmentspanbildung, Werkzeugverschleiß, Randschichtzustand und Bauteileigenschaften: Numerische Analysen zur Optimierung des Zerspanungsprozesses am Beispiel von Ti-6Al-4V

 

Lebenslauf:

seit 01/2017

Koordinator des Forschungsschwerpunkts Generative Fertigung

01/2015 - 12/2016

Koordinator des Forschungsschwerpunkts Mikroproduktion

seit 10/2014

Vertreter der wissenschaftlichen Mitarbeiter im Prüfungsausschuss Maschinenbau

seit 04/2014

Mitglied im Young Investigator Network (YIN) des KIT

seit 08/2013 Research Affiliate der CIRP 
05/2013 - 04/2014

Erfolgreich in der DFG-Nachwuchsakademie mit dem Projekt "Komplementärzerspanung"

07/2013 Dr.-Ing. Willy-Höfler-Doktorandenpreis für die beste Dissertation mit fertigungs-, mess- oder regelungstechnischer Zielsetzung
seit 01/2013 Lehrbeauftragter an der DHBW Karlsruhe
seit 12/2012 Geschäftsführer des Graduiertenkollegs 1483
seit 11/2012 Oberingenieur des Forschungsbereichs Fertigungs- und Werkstofftechnik am wbk - Institut für Produktionstechnik des Karlsruher Instituts für Technologie (KIT)
02.11.2012 Promotion: „Segmentspanbildung, Werkzeugverschleiß, Randschichtzustand und Bauteileigenschaften: Numerische Analysen zur Optimierung des Zerspanungsprozesses am Beispiel von Ti-6Al-4V“
01/2012 - 10/2012 Gruppenleiter des Forschungsbereichs Fertigungs- und Werkstofftechnik am wbk - Institut für Produktionstechnik des Karlsruher Instituts für Technologie (KIT)
10/2011 Baden-Württemberg Zertifikat für Hochschuldidaktik
02/2009 - 02/2015 Koordinator des Forschungsschwerpunkts Virtuelle Produktion
10/2007 – 10/2012 Wissenschaftlicher Mitarbeiter in der Gruppe Fertigungs- und Werkstofftechnik am wbk - Institut für Produktionstechnik des Karlsruher Instituts für Technologie (KIT)
06/2007 Diplomarbeit am wbk – Institut für Produktionstechnik, Thema: „Mathematische Modellierung des Wärmeeintrags bei der Fräsbearbeitung von EN-GJL-260 Cr“
2002 – 2007 Studium: Ingenieur-Pädagogik (Fachrichtung Maschinenbau und Mathematik) an der Universität Karlsruhe (TH)

Veröffentlichungen

[ 1 ] Fleischer, J.; Pabst, R. & Zanger, F. (2008), „Modellierung des Wärmeeintrages bei der Trockenbearbeitung von Fahrzeugkomponenten aus Grauguss“ in Spanende Fertigung, Hrsg. Weinert, K. & Biermann, D., Vulkan-Verlag GmbH, Essen, S. 233-243. ISBN/ISSN: 978-3-8027-2943-0
Abstract:
Die Trockenbearbeitung von Fahrzeugkomponenten aus Grauguss steht und fällt mit der Beherrschung des Prozesses. Die Werkzeug- und Maschinentechnik ist zumeist für den Einsatz der Trockenbearbeitung, auch mit Minimalmengenschmierung, geeignet. Allerdings entfällt durch den Verzicht auf KSS die Temperierung des Prozesses, wodurch ein zeitlich begrenzter, ungerichtet mehrdimensionaler Verzug des Bauteils resultiert, der bei Kenntnis der Wärmedichte des Prozesses mit FE‑Methoden quantitativ simuliert werden kann. Die Wärmedichte kann in aufwendigen Versuchsreihen für einzelne Werkzeuge messtechnisch bestimmt werden. Ziel dieses Beitrags ist es, erste mathematische Modelle zur Berechnung des Wärmeeintrags vorzustellen. Basierend auf diesen Modellen kann die Wärmedichte als Eingangsparameter für die Simulation berechnet werden. Dies erlaubt die thermische Simulation und damit auch die Optimierung des Bearbeitungsprozesses.

[ 2 ] Osterried, J.; Zanger, F. & Schulze, V. (2009), „chip formation simulations in hard machining“. 22. Workshop Composite Forschung der Mechanik /3. Forum Metallplastizität, 01.12.2009-02.12.2009, Paderborn, Deutschland, 22. Workshop Composite Forschung der Mechanik / 3. Forum Metallplastizität, Hrsg. Mahnken, R.; Böhlke, T.; Wünsch, O.; Nestler, B. & Schulze, V., S. 19.
Abstract:
Broaching of hardened steels is one of the sub-processes of the process-chain examined in Graduate School 1483. This topic aims at predicting the surface layer conditions, like residual stresses and distortion, after hard machining within the process chain. A hard machining strategy with minimal machining effort will be developed consequential for best possible surface layer and component conditions. Therefore the broaching of hardened materials is mapped to simulation, based on the component characteristics resulting from preceding heat treatment. In doing so, the component is machining history is taken into account when simulating broaching within the process chain. Based on a global view of the component at heat treatment, it is crucial to transfer quantities specifying component state to a local mesh for chip forming simulations. Input data from heat treatment simulation have to be implemented to describe the actual component condition before hard machining. This condition has then to be set as an accurately defined initial state for the hard machining simulation. Defining the initial state is of great importance for simulations within the process chain, as the sub-processes are linked by inheriting the respective component conditions like residual stress behaviour. Therefore appropriate techniques have to be provided. For the development of the machining strategy, simulations with varied process parameters can be triggered consequently. At the end of the hard machining simulation process the present output quantities have to be translated into a global mesh of the three-dimensional component.

[ 3 ] Osterried, J.; Zanger, F.; Autenrieth, H. & Schulze, V. (2010), „Neue Simulationsmethode zur Randschichtcharakterisierung unter Berücksichtigung der Mehrfachspanbildung beim Räumen“. 1. Klausurtagung des Graduiertenkollegs 1483, 3. Symposium des CCMSE, 25.02.2010-26.02.2010, Bad Herrenalb, Deutschland, Graduiertenkolleg 1483 Prozessketten in der Fertigung: Wechselwirkung, Modellbildung und Bewertung von Prozesszonen, Begleitband zur 1. Jährlichen Klausurtagung 2010, Hrsg. Pabst, R.; Nestler, B. & Schulze, V., Shaker Verlag, S. 57-61.
Abstract:
Um eine durchgängige Simulation einer Prozesskette, bestehend aus den Teilprozessen Weichbearbeitung, Wärmebehandlung, Hartbearbeitung und Oberflächenbehandlung, zu erreichen, müssen zunächst diese Teilschritte abgebildet und anschließend über geeignete Schnittstellen verkettet werden. Dadurch ist eine skalenübergreifende Betrachtung von lokaler Ebene im Einzelprozess bis zum globalen Bauteilzustand möglich. Das Bauteil innerhalb der fertigungstechnischen Prozesskette weist eine spezifische Bearbeitungsgeschichte auf. Diese vorliegenden Bauteilzustände müssen, als Voraussetzung zur Verkettung, zwischen den Teilprozessen übertragen werden können. Es wird eine Methode vorgestellt, um einem FE-Modell einen definierten Bauteilzustand als Anfangszustand vorzugeben. Das Aufprägen von Bauteilzuständen ermöglicht damit die Berücksichtigung der Bearbeitungsgeschichte und zudem die Durchführung von Mehrfachspansimulationen zur Abbildung des in der Prozesskette eingesetzten Räumverfahrens. Dazu werden die Zustände aus dem Nachlaufbereich der Schneide extrahiert und der Simulation des nächsten Zahnes unter Verwendung von Benutzerroutinen aufgeprägt. Die Spanbildungssimulation ist mittels Neuvernetzung realisiert.

[ 4 ] Zanger, F.; Autenrieth, H.; Hoffmeister, J. & Schulze, V. (2010), „Numerische Materialmodellierung und deren Anwendung in der virtuellen Produktion“. 1. Klausurtagung des Graduiertenkollegs 1483, 3. Symposium des CCMSE, 25.02.2010-26.02.2010, Bad Herrenalb, Deutschland, Graduiertenkolleg 1483 Prozessketten in der Fertigung: Wechselwirkung, Modellbildung und Bewertung von Prozesszonen, Begleitband zur 1. Jährlichen Klausurtagung 2010, Hrsg. Pabst, R.; Nestler, B. & Schulze, V., Shaker Verlag, S. 125-129.
Abstract:
Eine realitätsnahe Beschreibung von Fertigungsprozessen mit hohen Umformgraden setzt eine Berücksichtigung des Materialversagens im Werkstück voraus. Das Versagensverhalten zeigt eine Abhängigkeit von den Zustandsgrößen Spannungszustand, Verformungsgeschwindigkeit und Temperatur, die mittels analytischer Funktionen beschrieben werden können. Des Weiteren ist das Versagensverhalten werkstoffspezifisch. Eine realistische Materialmodellierung ermöglicht die simulative Abbildung unterschiedlichster Fertigungsprozesse, sodass stabile Prozessparameter identifiziert werden können. Die hier vorgestellten Materialmodelle für die beiden Werkstoffe C45E und Ti-6Al-4V, in denen das elastisch-viskoplastische Verformungs- und das duktile Versagensverhalten berücksichtigt wurden, konnten erfolgreich unter anderem zur Beschreibung dynamisch belasteter Scherproben eingesetzt werden (C45E). Zudem wurden diese Modelle zur Beschreibung von Spanbildungsprozessen (C45E und Ti-6Al-4V) und eines Umformprozesses eingesetzt (C45E). Die entwickelten Modelle erlaubten eine Beschreibung der Spanformen, der Prozesskräfte und Temperaturen in den Scherzonen. Diese zeigten eine gute Übereinstimmung mit den experimentellen Befunden.

[ 5 ] Schulze, V. & Zanger, F. (2011), „Development of a Simulation Model to Investigate Tool Wear in Ti-6Al-4V Alloy Machining“. 13th CIRP Conference on Modeling of Machining Operations (CIRP CMMO), 12.05.2011-13.05.2011, Sintra, Portugal, Modelling of Machining Operations, Hrsg. Trans Tech Publications, Trans Tech Publications, S. 535-544.
Abstract:
Titanium alloys like Ti‑6Al‑4V have a low density, a very high strength and are highly resistant to corrosion. However, the positive qualities in combination with the low heat conductivity have disadvantageous effects on mechanical machining and on cutting in particular. Ti‑6Al‑4V forms segmented chips for the whole range of cutting velocities which influences tool wear. Thus, optimization of the manufacturing process is difficult. To obtain this goal the chip segmentation process and the tool wear are studied numerically in this article. Therefore, a FEM model was developed which calculates the wear rates depending on state variables from the cutting simulation, using an empirical tool wear model. The segmentation leads to mechanical and thermal load variations, which are taken into consideration during the tool wear simulations. In order to evaluate the simulation results, they are compared with experimentally obtained results for different process parameters.

[ 6 ] Schulze, V.; Zanger, F.; Michna, J.; Ambrosy, F. & Pabst, R. (2011), „Investigation of the machining behavior of metal matrix composites (MMC) using chip formation simulation“. 13th CIRP Conference on Modeling of Machining Operations (CIRP CMMO), 12.05.2011-13.05.2011, Sintra, Portugal, Modelling of Machining Operations, Hrsg. Trans Tech Publications, Trans Tech Publications, S. 20-29.
Abstract:
The machining of metal matrix composites (MMC) induces cyclic loadings on tools, which creates new challenges for machining. In particular the distributed reinforcement, consisting of silicon carbide (SiC) or aluminum oxide (Al2O3), evokes especially high mechanical loads. The development of metal matrix composites is pointing towards higher fractions of reinforcements, which affects the resulting forces and temperatures. In this regard the influence of varying particle filling degrees, particle diameters, cutting velocities and tool geometries in terms of rake angle and cutting edge radius have been investigated by means of cutting simulation. For the process a self-designed continuous remeshing routine was used for which a dual phase material behavior has been implemented. The developed simulation model enables investigations of the machining behavior of metal matrix composites to the extent that ideal process strategies and tool geometries can be identified by multiple simulations.

[ 7 ] Schulze, V.; Michna, J.; Zanger, F. & Pabst, R. (2011), „Modeling the Process-Induced Modifications of the Microstructure of Work Piece Surface Zones in Cutting Processes“. 13th CIRP Conference on Modeling of Machining Operations (CIRP CMMO), 12.05.2011-13.05.2011, Sintra, Portugal, Modelling of Machining Operations, Hrsg. Trans Tech Publications, Trans Tech Publications, S. 371-380.
Abstract:
Cutting processes lead to mechanical and thermal loading of tool and work piece. This loading entails a direct influence of the cutting process on the surface layers of the manufactured work pieces. As a result, residual stresses and modifications of the micro-structure like white layers can occur in surface-near zones of the work piece. This paper presents the development of a FE-simulation model to predict phase transformations due to cutting processes. Therefore a 2D-FE-cutting simulation including a dynamic re-meshing is combined with a simulation routine to describe phase transformations that was primarily developed to simulate laser hardening. This paper illustrates the implemented mechanisms to determine phase transformations considering short time austenization and shows first experimental results revealing the influence of process parameters on the surfaces microstructure.

[ 8 ] Schulze, V.; Osterried, J.; Meier, H. & Zanger, F. (2011), „Simulation of Multiple Chip Formation when Broaching SAE 5120 Low Alloy Steel“. 13th CIRP Conference on Modeling of Machining Operations (CIRP CMMO), 12.05.2011-13.05.2011, Sintra, Portugal, Modelling of Machining Operations, Hrsg. Trans Tech Publications, Trans Tech Publications, S. 37-45.
Abstract:
The paper aims to predict component conditions after each subprocess of a manufacturing process chain. A continuous simulation has to be achieved, considering the inheritance of component states. To identify functional descriptions between component conditions as input and output quantities a broaching simulation is being developed. It includes multiple chip formation with multi-toothed broaching tools and machining history of a component as well. For this purpose component conditions are extracted from and transferred to a workpiece model as an initial condition. The 2D finite element chip formation model uses remeshing for material separation allowing highly detailed surface layer characterizations. Parallel experimental studies vary process parameters, whose objective is optimization of process control and forecast of component properties. Characterization of component conditions is based on distortion analysis, cutting force and surface measurements. Comparing the specific cutting forces between simulation model and performed experiments show a reasonable agreement of results.

[ 9 ] Schulze, V. & Zanger, F. (2011), „Numerical Analysis of the Influence of Johnson-Cook-Material Parameters on the Surface Integrity of Ti-6Al-4 V “. 1st CIRP Conference on Surface Integrity (CSI), 30.01.2012-01.02.2012, Bremen, Deutschland, Procedia Engineering 19, Hrsg. Prof. E. Brinksmeier, S. 306-311.
Abstract:
During machining metals the material of the work piece is highly deformed and heated, which influences surface integrity. To simulate the machining process the thermo-mechanical material behavior in dependence of strain, strain rate and temperature has to be well known. One of the most used material models is the Johnson-Cook-Model, where the material dependent parameters are determined by Split-Hopkinson pressure bar tests. For the titanium alloy Ti-6Al-4 V used for the simulations different investigations with the goal of determining material parameters have been published. However, the presented results vary significantly. It is expected that these varying parameters result in different predictions of surface integrity after machining. This influence is investigated by machining simulations using a self-developed continuous remeshing method.

[ 10 ] Zanger, F. (2012), Segmentspanbildung, Werkzeugverschleiß, Randschichtzustand und Bauteileigenschaften: Numerische Analysen zur Optimierung des Zerspanungsprozesses am Beispiel von Ti-6Al-4V. Dissertation.
Abstract:
An die Lebensdauer hochbelasteter Bauteile wie Verdichterräder in Turboladern werden aufgrund der steigenden Relevanz von Ressourcen- und Energieeffizienz wachsende Ansprüche gestellt. Diese Bauteile werden häufig aus Leichtbaumaterialien wie Metall-Matrix-Verbundwerkstoffen oder Titanlegierungen hergestellt. Wegen ihrer guten mechanischen und thermischen Materialeigenschaften wird häufig die Titanlegierung Ti-6Al-4V eingesetzt. Bei der zerspanenden Bauteilherstellung von Komponenten aus Ti-6Al-4V führt deren hohe Zugfestigkeit in Kombination mit einem geringen E-Modul und einer geringen Wärmeleitfähigkeit zu großen Belastungen der verwendeten Werkzeuge, was zu einem besonders schnellen Verschleißwachstum führt. Der Verschleiß am Werkzeug ist gekennzeichnet durch eine Änderung der idealen Werkzeuggeometrie, wodurch die Prozessbedingungen beeinflusst werden. Veränderte Prozessbedingungen führen wiederum zur Beeinflussung der erzielbaren Bauteiloberflächen in Form von makroskopisch erkennbaren Rauheiten bis hin zu Mikrodefekten der Randschicht. Diese Beeinflussung des Bauteilzustandes führt zu einem veränderten Bauteilverhalten bei Funktionsbauteilen und zu einer Variation der Lebensdauer bei hoch beanspruchten Bauteilen. Sowohl der Werkzeugverschleiß als auch die resultierenden Bauteilzustände und eigenschaften nach der Zerspanung werden von den Prozessparametern und der Werkzeuggeometrie beeinflusst. Die Kenntnis des Verschleißfortschritts und der dadurch beeinflussten Bauteilqualität ermöglicht eine Optimierung der Prozessbedingungen. Um dies zu erreichen, werden in der vorliegenden Arbeit Simulationsmodelle vorgestellt, die ausgehend von Zerspanungssimulationen über die Simulation des Werkzeugverschleißes sowie der resultierenden Bauteilzustände und eigenschaften eine ganzheitliche Prozessoptimierung ermöglichen. Mittels umfangreicher zerspanungstechnologischer Untersuchungen erfolgt neben einer Prozesscharakterisierung die Validierung der Simulationsmodelle. In der abschließenden Prozessoptimierung wird gezeigt, dass bei gezielter Prozessparameterwahl eine hervorragende Kombination aus Werkzeugstandzeit und den damit erreichbaren Bauteileigenschaften erzielt werden kann.

[ 11 ] Zanger, F. (2012), Segmentspanbildung, Werkzeugverschleiß, Randschichtzustand und Bauteileigenschaften: Numerische Analysen zur Optimierung des Zerspanungsprozesses am Beispiel von Ti-6Al-4V, Shaker, Aachen. ISBN/ISSN: 978-3-8440-1645-1
Abstract:
An die Lebensdauer hochbelasteter Bauteile wie Verdichterräder in Turboladern werden aufgrund der steigenden Relevanz von Ressourcen- und Energieeffizienz wachsende Ansprüche gestellt. Diese Bauteile werden häufig aus Leichtbaumaterialien wie Metall-Matrix-Verbundwerkstoffen oder Titanlegierungen hergestellt. Wegen ihrer guten mechanischen und thermischen Materialeigenschaften wird häufig die Titanlegierung Ti 6Al 4V eingesetzt. Bei der zerspanenden Bauteilherstellung von Komponenten aus Ti 6Al 4V führt deren hohe Zugfestigkeit in Kombination mit einem geringen E-Modul und einer geringen Wärmeleitfähigkeit zu großen Belastungen der verwendeten Werkzeuge, was zu einem besonders schnellen Verschleißwachstum führt. Der Verschleiß am Werkzeug ist gekennzeichnet durch eine Änderung der idealen Werkzeuggeometrie, wodurch die Prozessbedingungen beeinflusst werden. Veränderte Prozessbedingungen führen wiederum zur Beeinflussung der erzielbaren Bauteiloberflächen in Form von makroskopisch erkennbaren Rauheiten bis hin zu Mikrodefekten der Randschicht. Diese Beeinflussung des Bauteilzustandes führt zu einem veränderten Bauteilverhalten bei Funktionsbauteilen und zu einer Variation der Lebensdauer bei hoch beanspruchten Bauteilen. Sowohl der Werkzeugverschleiß als auch die resultierenden Bauteilzustände und eigenschaften nach der Zerspanung werden von den Prozessparametern und der Werkzeuggeometrie beeinflusst. Die Kenntnis des Verschleißfortschritts und der dadurch beeinflussten Bauteilqualität ermöglicht eine Optimierung der Prozessbedingungen. Um dies zu erreichen, werden in der vorliegenden Arbeit Simulationsmodelle vorgestellt, die ausgehend von Zerspanungssimulationen über die Simulation des Werkzeugverschleißes sowie der resultierenden Bauteilzustände und eigenschaften eine ganzheitliche Prozessoptimierung ermöglichen. Mittels umfangreicher zerspanungstechnologischer Untersuchungen erfolgt neben einer Prozesscharakterisierung die Validierung der Simulationsmodelle. In der abschließenden Prozessoptimierung wird gezeigt, dass bei gezielter Prozessparameterwahl eine hervorragende Kombination aus Werkzeugstandzeit und den damit erreichbaren Bauteileigenschaften erzielt werden kann.

[ 12 ] Schulze, V.; Klotz, S. & Zanger, F. (2012), „Experimentelle Untersuchung von Bauteilschädigung und Werkzeugverschleiß bei der FVK-Bearbeitung“ in Spanende Fertigung, Hrsg. Biermann, D., Vulkan-Verlag, Essen, S. 330-337. ISBN/ISSN: 978-3-8027-2965-2
Abstract:
In den vergangenen Jahren hat der Einsatz von faserverstärkten Kunststoffen (FVK) immer weiter an Bedeutung gewonnen. Als einer der Treiber dieser Weiterentwicklung hat die Automobilindustrie in der jüngsten Vergangenheit verstärkt den Leichtbau mit Faserverbundbauteilen fokussiert. Die Gründe hierfür liegen beispielsweise in immer höheren Anforderungen an den Umweltschutz und den erforderlichen Gewichtsreduktionen [1]. Die Faserverbundwerkstoffe sind hier mit ihrer besseren spezifischen Steifigkeit und Festigkeit den Metallen deutlich überlegen. Zudem können durch die gezielte Anpassung von Faserverläufen an die vorliegenden Lastpfade weitere Gewichtsreduktionen erfolgen. Bauteile aus Faserverbundwerkstoffen werden meist endkonturnah hergestellt. Aus fertigungstechnischen Gründen ist jedoch eine Nachbearbeitung, beispielsweise bei der Herstellung von Bohrungen, für die spätere Montage oder zur Fügestellenvorbereitung, erforderlich. In den Bereichen, in denen die Bauteile nachbearbeitet werden, werden die Faserverläufe jedoch wieder unterbrochen, was zu einer Schwächung der Bauteile führt. Durch ungünstige Bearbeitungskräfte bei der Bearbeitung entstehen zudem Schädigungen an den Randzonen des Bauteils, die dieses weiter schwächen. Das primäre Ziel bei der Nachbearbeitung von FVK-Bauteilen ist es daher, bearbeitungsinduzierte Schädigungen zu vermeiden. Der zunehmende Einsatz von Faserverbundwerkstoffen, auch in Bereichen der Großserienfertigung, erfordert jedoch auch neue Herstelltechnologien, welche die wirtschaftlichen Anforderungen der Serienfertigung berücksichtigen [1]. Neben der Fertigungsqualität gewinnen die Fertigungskosten bei der Bearbeitung von FVK zur Sicherung der Wettbewerbsfähigkeit immer mehr an Bedeutung. Daher sind neben geringen Schädigungen möglichst geringe Prozesskosten ebenfalls ein wichtiger Bestandteil für den wirtschaftlichen Serieneinsatz von Faserverbundwerkstoffen.

[ 13 ] Schulze, V.; Boev, N. & Zanger, F. (2012), „Simulation of Metal Cutting Process with Variable Cutting Thickness During Broaching “. 5th CIRP Conference on High Performance Cutting 2012, 04.06.2012-06.06.2012, Zürich, Schweiz, Procedia CIRP 1, Hrsg. Konrad Wegener, S. 437-442.
Abstract:
With the advancements of different simulation approaches several metal cutting processes have been simulated, investigated and improved. However, very little work has been published in the field of metal cutting with variable cutting thicknesses by means of cutting simulations. This paper presents a 2D cutting simulation approach using the finite element method (FEM), which is applied in order to predict cutting forces, temperatures and chip shapes while broaching. To investigate the influence of varying cutting thicknesses the broaching process is simulated with different constant cutting thicknesses at the beginning (20, 35 μm and 50 μm).

[ 14 ] Schulze, V.; Boev, N. & Zanger, F. (2012), „Numerical Investigation of the Changing Cutting Force Caused by the Effects of Process Machine Interaction While Broaching “. 3rd CIRP Conference on Process Machine Interaction, 29.10.2012-30.10.2012, Nagoya, Japan, Procedia CIRP 4, Hrsg. Prof. Eiji Shamoto, S. 140-145.
Abstract:
During broaching, interactions between the process and the machine are inevitable and affect the process itself and the resulting work piece. To understand these effects profoundly, they have to be analyzed and investigated. One of these effects is the vibration of the cutting edge which results for example in a change in rake angle or cutting thickness during the cutting process. Therefore, the first part of this paper presents results o f investigations concerning a variable cutting thickness and the second includes investigations of the variable rake angle during broaching, in both cases the effects on the cutting forces by means of two-dimensional (2D) cutting simulations.

[ 15 ] Schulze, V.; Ambrosy, F. & Zanger, F. (2012), „Spanender Endbearbeitungsprozess zur Modifizierung der Randzonenzustände“, Konstruktion - Zeitschrift für Produktentwicklung und Ingenieur-Werkstoffe, S. 14-16.
Abstract:
Endbearbeitungsprozesse sind heute primär auf das Erreichen der in den Bauteilzeichnungen festgelegten Maße und Oberflächenrauheiten ausgerichtet. Die gezielte Fertigung von Randzonen, welche ein optimiertes tribologisches Verhalten im Betrieb ermöglichen, stellt bisher kein Optimierungsziel dar. Die Bildung dieser triboinduzierten Grenzschichten beginnt jedoch schon während der Fertigung. Der Endbearbeitungsprozess führt sowohl zu Änderungen der Topografie als auch zu Modifikationen der strukturellen Zusammensetzung des oberflächennahen Werkstoffvolumens. Bei optimierter Fertigung können so gezielt bereits im letzten Bearbeitungsschritt nanokristalline Randschichten erzeugt werden, welche das Reibungs- und Verschleißverhalten günstig beeinflussen.

[ 16 ] Schulze, V.; Hoffmeister, J.; Zanger, F.; Ambrosy, F. & Erz, A. (2012), „Development of a microstructured deep rolling tool for generation of nanocrystalline surface layer“. Euspen Topical Meeting: Structured & Freeform Surfaces, 05.12.2012-06.12.2012, Teddington, UK, Topical Meetings Structured & Freeform Surfaces , Hrsg. European Society for Precision Engineering & Nanotechnology, S. 57-80.
Abstract:
The focus of this paper is the development of a modified deep rolling tool. Here, the effects of the variation of the roller surface microstructuring are studied. After machining with the modified tool the work piece surface shall remain plane and without microstructures, whereas the grain size in the surface layer shall be reduced drastically. A negative influence on fatigue life is possible due to a folding of the material on the work piece surface attributed to discontinuous deformation. Multiple EDM process variations were used to define microstructures on the roller surface, which increase shearing at the work piece and initiate the formation of a nanocrystalline surface layer during the deep rolling process.

[ 17 ] Schulze, V.; Osterried, J.; Strauß, T. & Zanger, F. (2012), „Analysis of surface layer characteristics for sequential cutting operations“, HTM Journal of heat treatment and materials, Band 67, S. 347-356. doi: 10.3139/105.110170
Abstract:
For manufacturing processes like milling, broaching and skiving tools with multiple cutting edges are used. The geometry and the characteristics of the machined components are the result of sequential cuts. A finite element model is built up including the sequential cutting by transferring component states between work piece models. The model is validated by comparing residual stresses between numerical and experimental results. Small element sizes allow for a detailed resolution of quantities describing the component state. Characteristics of the specific depth profiles are used for the analysis of residual stresses. The influence of process parameters and the number of simulated sequential cuts are examined. Sequential cuts show an influence on surface residual stresses. Residual stresses decrease for low cutting velocities and slightly increase for high cutting velocities. Tensile stresses also reach to deeper areas of the surface layer with increasing number of cuts. Compressive stresses pass through a significant maximum before decreasing to a constant value. A steady stress state is identified after ten sequential cuts.

[ 18 ] Schulze, V. & Zanger, F. (2012), „Untersuchung der Zerspanung von Metall-Matrix-Verbundwerkstoffen (MMC) mittels Finite-Elemente-Simulationen“ in Spanende Fertigung, Hrsg. Biermann, D., Vulkan-Verlag GmbH, Essen, S. 51-58. ISBN/ISSN: 978-3-8027-2965-2
Abstract:
Am wbk- Institut für Produktionstechnik wurde eine Methode für die FE-Zerspanungssimulation mehrphasiger Werkstoffmaterialien auf Mikroebene entwickelt und hier vorgestellt. Dazu wurden zwei verschiedene Werkstoffe mit unterschiedlichen Materialmodellen implementiert. Die Spanbildung konnte mittels einer selbstentwickelten Neuvernetzung in ABAQUS/Standard realisiert werden. Die hier vorgestellten Ergebnisse zeigen, dass das Simulationsmodell für eine präzise Vorhersage der in den Prozesszonen wirkenden Spannungen, Deformationen, Temperaturen und der daraus an den Werkzeugen resultierenden Kräfte geeignet ist, sodass die Wechselwirkungen unterschiedlicher Prozessparameter und Geometriegrößen sowie der Werkstoffzusammensetzung auf die resultierenden mechanischen und thermischen Werkzeugbelastungen in weiteren Analysen untersucht und diskutiert werden können.

[ 19 ] Schulze, V.; Michna, J.; Zanger, F.; Faltin, C.; Maas, U. & Schneider, J. (2013), „Influence of cutting parameters, tool coatings and friction on the process heat in cutting processes and phase transformations in workpiece surface layers“, HTM Journal of Heat Treatment and Materials, Band 68, S. 22-31.
Abstract:
The surface states and thus the functionality of machined workpieces are influenced by parameters of the process and the cutting tool. Depending on these variables different mechanical and thermal loads lead to changing characteristics of components. This paper presents a 2D-FE-cutting simulation model predicting machining induced phase transformations of workpiece surface layers for the steel 42CrMo4 (AISI 4140) considering detailed friction modeling between tool and workpiece, based on tribological experiments. The cutting simulation model was developed using the commercial software ABAQUS. Friction and phase transformations are implemented using specific user subroutines. The model calculates the process of austenization and the transformed volume fraction of the phases ferrite/perlite, bainite and martensite. Additional thermo dynamical simulations of the heat transfer using the code INSFLA are performed. The simulated temperatures, cutting forces and phase transformations are compared to orthogonal cutting experiments.

[ 20 ] Kümmel, J.; Poser, K.; Zanger, F.; Michna, J. & Schulze, V. (2013), „Surface layer states of worn uncoated and TiN-coated WC/Co-cemented carbide cutting tools after dry plain turning of carbon steel“, Advances in Tribology, S. 1-10. http://dx.doi.org/10.1155/2013/519686
Abstract:
Analyzing wearmechanisms and developments of surface layers inWC/Co-cemented carbide cutting inserts is of great importance for metal-cutting manufacturing. By knowing relevant processes within the surface layers of cutting tools during machining the choice of machining parameters can be influenced to get less wear and high tool life of the cutting tool. Tool wear obviously influences tool life and surface integrity of the workpiece (residual stresses, surface quality, work hardening, etc.), so the choice of optimised process parameters is of great relevance. Vapour-deposited coatings onWC/Co-cemented carbide cutting inserts are known to improve machining performance and tool life, but the mechanisms behind these improvements are not fully understood. The interaction between commercial TiN-coated and uncoated WC/Co-cemented carbide cutting inserts and a normalised SAE 1045 steel workpiece was investigated during a dry plain turning operation with constant material removal under varied machining parameters. Tool wear was assessed by light-optical microscopy, scanning electron microscopy (SEM), and EDX analysis.The state of surface layer was investigated by metallographic sectioning. Microstructural changes and material transfer due to tribological processes in the cutting zone were examined by SEM and EDX analyses.

[ 21 ] Schulze, V.; Zanger, F.; Krausse, M. & Boev, N. (2013), „Simulation Approach for the Prediction of Surface Deviations Caused by Process-Machine-Interaction During Broaching “. 14th CIRP Conference on Modeling of Machining Operations (CIRP CMMO), 13.06.2013-14.06.2013, Turin, Italy, Procedia CIRP 8, Hrsg. Prof. Luca Settineri, S. 252-257.
Abstract:
Broaching is a highly efficient metal machining process in mass production. Parts with high quality requirements are manufactured by broaching, which can be influenced by different factors. One of them is vibration caused by process-machine-interactions. Such vibrations can easily be investigated with external broaching, where these vibrations result in varying process forces and wavily profiled machining surfaces. This paper presents a 2D FEM-simulation approach for the prediction of surface rough-ness generated by broaching. In the simulation model, the solid machine structure that consists of a large number of machine parts is realized by using elements representing the stiffness and the dynamic properties of the machine structure. Thus, it is possible to avoid high calculation times. The broach is implemented as an elastic body and the resulting process forces are realized by an analytical model that considers the process parameters cutting thickness, cutting velocity and rake angle. These process parameters are calculated for each increment, which allows determining the resulting process forces and applying them onto the teeth. Finally, the presented simulation approach for the prediction of the surface roughness generated by broaching is validated by means of experiments. Broaches with different numbers of teeth are used for the experimental setup.

[ 22 ] Zanger, F. & Schulze, V. (2013), „Investigations on Mechanisms of Tool Wear in Machining of Ti-6Al-4V Using FEM Simulation“. 14th CIRP Conference on Modeling of Machining Operations (CIRP CMMO), 13.06.2013-14.06.2013, Turin, Italy, Procedia CIRP 8, Hrsg. Prof. Luca Settineri, S. 158-163.
Abstract:
The titanium alloy Ti-6Al-4V is used very often for highly stressed components like compressor wheels because of its excellent mechanical and thermal properties. However, when machining components made of Ti-6Al-4V, their high tensile strength in combination with a low Young's modulus and a low thermal conductivity leads to high thermal and mechanical stresses in the cutting tools, which in turn lead to a particularly fast tool wear. Thus, optimization of the manufacturing process is required. However, to obtain this goal the mechanisms of tool wear were studied numerically and some results are presented in this article. Ti-6Al-4V forms segmented chips for the whole range of cutting velocities. The mechanical and thermal load variations due to the segmentation are taken into consideration during these investigations. A FEM model using a self-developed continuous remeshing method to form segmented chips was developed. Thus resulting state variables like stresses, temperatures and relative velocities between the tool face and the chip along the cutting tool can be investigated, which are well known for influencing tool wear in machining. The distributions of these state variables along the cutting tool, especially in the area of the cutting edge, are analyzed and related to experimentally caused tool wear. In order to evaluate the developed simulation model, orthogonal cutting experiments have been conducted with uncoated carbide (WC/Co) cutting tools. Simulated results are compared with experimentally obtained data for different process parameters.

[ 23 ] Schulze, V.; Zanger, F.; Michna, J. & Lang, F. (2013), ԫD-FE-Modelling of the Drilling Process – Prediction of Phase Transformations at the Surface Layer “. 14th CIRP Conference on Modeling of Machining Operations (CIRP CMMO), 13.06.2013-14.06.2013, Turin, Italy, Procedia CIRP 8, Hrsg. Prof. Luca Settineri, S. 33-38.
Abstract:
Due to friction, plastic deformation and cutting, the drilling process leads to high mechanical and thermal loadings of drilling tool and workpiece. Distortion and modifications of the surface layer microstructure, especially rehardened zones, can be observed, whereby the experimental investigation of correlations between machining processes and resulting surface layers are very complicated and time consuming. This paper presents a numerical approach to predict machining induced phase transformations at the surface layer of drilled holes. Based on experimental results and 2D FE machining simulations, an abstract model representing the mechanical and thermal collective load of the drilling process has been developed in relation to the parameters cutting speed and feed rate. To predict phase transformations of the steel 42CrMo4 (AISI 4140) at the surface layer of drilled holes a 3D FE-model has been established using the commercial software ABAQUS. The kinetics of the phase transformations are implemented using specific user subroutines. The model calculates the process of austenization and the transformed volume fraction of the phases ferrite/perlite, bainite and martensite and also considers transformation plasticity and the resulting hardness of the microstructure. By simulating different combinations of cutting parameters, relations between drilling process and resulting surface layers of drilled holes have been studied. In addition the machining induced distortion of the workpiece can be calculated simultaneously. The simulation model has been verified by drilling experiments, thermal imaging and metallographic investigations. Predicting machining induced surface layer states, the functionality of future components can be improved.

[ 24 ] Schulze, V.; Zanger, F. & Boev, N. (2013), „Numerical Investigations on Changes of the Main Shear Plane while Broaching “. 14th CIRP Conference on Modeling of Machining Operations (CIRP CMMO), 13.06.2013-14.06.2013, Turin, Italy, Procedia CIRP 8, Hrsg. Prof. Luca Settineri, S. 246-251.
Abstract:
The quality of broached components can be influenced by different factors, such as am-bient temperatures, human factors or vibrations of the machine structure induced by process-machine-interactions. These vibrations are normally initiated by changing pro-cess forces, which are mainly caused by cutting thickness or rake angle variations. Broached components are produced within one motion of the broach along the surface of the work piece, where multiple teeth in a row are in contact. The variation of the cut- ting thickness results from a wavy profile on the surface generated by the previous cut-ting process or the previous tooth. When the cutting thickness changes during the process, the rake angle varies, too. In some further published works, the changing cutting thickness and the changing rake angle during broaching were investigated by means of machining simulations with the result that the process forces are still adjusting after the cutting thickness and the rake angle have already reached a stable value. The adjustment of the shear plane on the new cutting conditions is mentioned as the main reason. This paper presents some deeper investigations on this effect. Therefore, 2D machining simulations for different cutting thicknesses and cutting velocities are performed. The investigations show tendencies for the still adjusting shear plane after changing the cutting thickness or the rake angle during the cutting process. Finally, the simulation results are validated with experimentally observed data.

[ 25 ] Schulze, V.; Arrazola, P. J.; Zanger, F. & Osterried, J. (2013), „Simulation of Distortion Due to Machining of Thin-walled Components “. 14th CIRP Conference on Modeling of Machining Operations (CIRP CMMO), 13.06.2013-14.06.2013, Turin, Italy, Procedia CIRP 8, Hrsg. Prof. Luca Settineri, S. 45-50.
Abstract:
The distortion of components is strongly related to the residual stress state induced by manufacturing processes like heat treatment, forming or machining. Each process step affects the initial stress state of the following process step. When removing material during machining, the component establishes a new stress equilibrium. Stresses are redistributed causing the component geometry to adjust. Especially for thin-walled components distortion potential is high. Gaining knowledge about the influence of initial loads and the release of distortion during machining processes helps to increase product quality and efficiency. The influences of different initial stress states and different machining parameters on the amount of distortion are examined using both FEM simulations and experiments. A thin-walled T-profile made of aluminum alloy Al 7075-T6 serves as test specimen. A bending process applies a load to initialize a repeatable and defined residual stress state. A groove was machined afterwards into the plastically deformed work piece to trigger stress redistribution and a release of distortion. Different loads with 35 to 45 kN and two different geometries of a groove were used. The amount of initial stress has a significant effect on the distortion potential which could be quantified in the study. Simulations show the same behavior as the experiments and the results match very well especially for a high load.

[ 26 ] Schulze, V.; Zanger, F. & Klotz, S. (2013), „Verschleißbedingte Parameteranpassung bei der Bohrungsherstellung in faserverstärkten Kunststoffen“. 19. Symposium Verbundwerkstoffe und Werkstoffverbunde, 03.07.2013-05.07.2013, Karlsruhe, Deutschland, Verbundwerkstoffe, Hrsg. Wanner, A. & Weidenmann, K. A., S. 658-664.
Abstract:
Faserverstärkte Kunststoffe besitzen entlang der Faserrichtung hohe spezifische Festigkeiten und Steifigkeiten. Trotz deren meist endkonturnaher Herstellung müssen teilweise noch Bohrungen in die Bauteile eingebracht werden. Bei der Bohrbearbeitung entstehen Bearbeitungskräfte, die senkrecht zur Verstärkungsrichtung der Fasern wirken. Diese Prozesskräfte verursachen an den Decklagen Schädigungen in Form von Ausfransungen und Delaminationen. In den meisten Fällen werden die Bohrungen mit über die gesamte Werkzeugstandzeit gleichbleibenden Prozessparametern eingebracht. Bestehende Ansätze zur Vermeidung der Bauteilschädigungen zielen lediglich auf eine Reduzierung der Vorschubgeschwindigkeiten im Bereich des Bohrungsaustritts ab, um dort die kritischen Prozesskräfte zu verringern. Bei der Bohrbearbeitung mit konstanten Parametern verändern sich in Abhängigkeit des Verschleißzustands des Bohrwerkzeugs die Eingriffsverhältnisse der Werkzeugschneide, was in sich verändernden Prozesskraftrichtungen und zunehmenden Werkstückschädigungen resultiert. Eine andere Möglichkeit, die Schädigungen an den Bauteilen zu verringern, besteht daher in der dynamischen Anpassung der Prozessparameter an den aktuellen Verschleißzustand des Werkzeugs. Damit können durch die Einstellung von konstanten Eingriffsverhältnissen zwischen Werkzeugverschleiß und Schnitttiefe über die gesamte Werkzeuglebensdauer die Schädigungen an den Decklagen gezielt verringert werden. Es werden die Ergebnisse einer Versuchsreihe mit unterschiedlichen Eingriffsverhältnissen, einer Referenzuntersuchung sowie deren Auswirkungen auf die entstehenden Bauteilschädigungen vorgestellt.

[ 27 ] Schulze, V.; Zanger, F. & Ambrosy, F. (2013), „Investigation of the Impact of Orthogonal Cutting Processes on Nanocrystalline Surface Layer Generation“. 16th annual ESAFORM Conference on Material Forming, 22.04.2013-24.04.2013, Aveiro, Portugal, The Current State-of-the-Art on Material Forming, Hrsg. Trans Tech Publications, S. 2009-2020.
Abstract:
The present work analyzes the influence of an orthogonal machining process on the generation of nanocrystalline surface layers. Thereby, AISI 4140 is used as work piece material. Metallic parts with a severe nanocrystalline grain refinement in the near-surface area show many beneficial properties. Such surface layers considerably influence the friction and wear characteristics of the work piece in a subsequent usage as design elements working under tribological loads. The focus of this paper is an experimental analysis of a finishing orthogonal cutting operation, carried out with a broaching machine, to generate nanocrystalline surface layers. The influence of process and geometry parameters on the generation of nanocrystalline surfaces is investigated with the aim to massively decrease the grain size in the work piece surface layer. Parameters that are studied and taken into account in the manufacturing process are cutting edge radius r_beta, depth of cut h and cutting velocity vc. The cutting edge radius r_beta is modified by a drag finishing process. The generation of nanocrystalline surface layers is especially influenced by the design of the uncoated carbide cutting tools. Additionally, cutting force Fc and passive force Fp are determined by a 3-component dynamometer to calculate the relationship between specific cutting force kc and specific passive force kp. The temperature beneath the clearance face is detected by a fiber optic pyrometer. These measurement methods and devices are applied to detect the impact of the most relevant measurement values occurring during machining and causing a drastic reduction of grain size in the surface layer. The evaluation of the manufacturing process is carried out by detailed analyses of the microstructural conditions in the surface layer after processing using a Focused Ion Beam (FIB) system. These material characterizations provide information about the surface engineering concerning the microstructural changes in the surface layer of the work piece due to finishing orthogonal cutting processes.

[ 28 ] Schulze, V.; Zanger, F. & Ambrosy, F. (2013), „Quantitative Microstructural Analysis of Nanocrystalline Surface Layer Induced by a Modified Cutting Process“. WGP Congress 2013, 22.07.2013-23.07.2013, Erlangen, Deutschland, WGP Congress 2013, Hrsg. Trans Tech Publications, S. 109-115.
Abstract:
Present work analyzes the influence of process and modified geometry parameters of an orthogonal final machining process (finishing) on the nanocrystalline surface layers generation by quantitative microstructural analysis. Thereby, AISI 4140 (German Steel 42CrMo4) in a state quenched and tempered at 450°C is used as workpiece material. Metallic materials used in technical applications are polycrystalline in nature and are composed of a large number of grains which are separated by grain boundaries. The grain size has a strong influence on the mechanical material properties. Metallic parts with a severe nanocrystalline grain refinement in the near-surface area show many beneficial properties. Such surface layers considerably influence the friction and wear characteristics of the workpiece in a subsequent usage as design elements working under tribological loads due to their extreme superplastic properties. The tribologically induced surface layers formation already starts during the manufacturing of the components, by leading to a change of workpiece material near the surface. Particularly when the depth of cut h becomes of the same order as the cutting edge radius r_beta, the ploughing process becomes increasingly important and strongly influences the chip formation process. The plastic zone depth within the surface layer is especially influenced by the design of the microgeometry of the cutting tools and increases almost linearly with the ratio of cutting edge radius r_beta to depth of cut h. The plastic zone is hereby approximately of the same order of magnitude as the cutting edge radius r_beta. Parameters that are studied and taken into account in the manufacturing process are cutting edge radius r{\ss }, depth of cut h and cutting velocity vc. Variations of cutting depth h are performed in a range of 30 to 100 µm and variations of cutting edge radius r_beta are executed in a range of 30 to 150 µm. The microgeometries of the tools are preconditioned by abrasive grinding with a drag finishing machine and observed by a confocal light microscope. A cutting velocity vc of 25 and 150 m/min is applied. The evaluation of the manufacturing process is carried out by detailed analyses of the microstructural conditions in the surface layer after processing using a Focused Ion Beam system. These material characterizations provide information about the surface engineering concerning the microstructural changes in the workpiece surface layer due to machining. Hereby, the grain size analysis is investigated by a line method based on the characterization of portions of several test-lines positioned across the two dimensional Focused Ion Beam images.

[ 29 ] Schulze, V.; Zanger, F.; Deuchert, M. & Hoppen, P. (2013), „Compensating the cutting edge displacement during micro milling - a mechatronic approach“. International Conference on Multi-Material Micro Manufacture, 08.10.2013-10.10.2013, San Sebastian, Spanien, Proceedings of the 10th International Conference on Multi-Material Micro Manufacture, Hrsg. Sabino Azcárate and Stefan Dimov, S. 225-228.
Abstract:
The turnover of micro system technology (MST)-based products increases within the next years. This Ieads to the challenge of reliable processes with narrow tolerances. Processes as micro milling still have to deal with scale effects and narrow tolerances usually are only producible with high efforts. This article shows a mechatronic clamping system to compensate several inaccuracies at once. The cutting edge displacement results from inaccuracies in the machine tool , the clamping system and the milling tool. Compensating the cutting edge displacement while rotating with nominal rpm is an effective way to increase the accuracy up to 1 µm.

[ 30 ] Gerstenmeyer, M.; Klotz, S.; Zanger, F. & Schulze, V. (2013), „Untersuchungen zum Einspannen von FVK“, MM Maschinenmarkt Composites World, S. 14-17.
Abstract:
Faserverstärkte Kunststoffe liegen im trend und müssen nach ihrer meist endkonturnahen Fertigung noch spanend bearbeitet werden, um einsatzfähig zu sein. Was beim Einspannen von Composites zu beachten ist, damit sie nicht beschädigt werden, zeigt folgender Artikel.

[ 31 ] Schulze, V.; Zanger, F. & Ambrosy, F. (2013), „Quantitative Microstructural Analysis of Nanocrystalline Surface Layer Induced by a Modified Cutting Process“, Advanced Materials Research, Band 769, S. 109-115. 10.4028/www.scientific.net/AMR.769.109
Abstract:
Present work analyzes the influence of process and modified geometry parameters of an orthogonal final machining process (finishing) on the nanocrystalline surface layers generation by quantitative microstructural analysis. Thereby, AISI 4140 (German Steel 42CrMo4) in a state quenched and tempered at 450°C is used as workpiece material. Metallic materials used in technical applications are polycrystalline in nature and are composed of a large number of grains which are separated by grain boundaries. The grain size has a strong influence on the mechanical material properties. Metallic parts with a severe nanocrystalline grain refinement in the near-surface area show many beneficial properties. Such surface layers considerably influence the friction and wear characteristics of the workpiece in a subsequent usage as design elements working under tribological loads due to their extreme superplastic properties. The tribologically induced surface layers formation already starts during the manufacturing of the components, by leading to a change of workpiece material near the surface. Particularly when the depth of cut h becomes of the same order as the cutting edge radius rß, the ploughing process becomes increasingly important and strongly influences the chip formation process. The plastic zone depth within the surface layer is especially influenced by the design of the microgeometry of the cutting tools and increases almost linearly with the ratio of cutting edge radius rß to depth of cut h. The plastic zone is hereby approximately of the same order of magnitude as the cutting edge radius rß. Parameters that are studied and taken into account in the manufacturing process are cutting edge radius rß, depth of cut h and cutting velocity vc. Variations of cutting depth h are performed in a range of 30 to 100 µm and variations of cutting edge radius rß are executed in a range of 30 to 150 µm. The microgeometries of the tools are preconditioned by abrasive grinding with a drag finishing machine and observed by a confocal light microscope. A cutting velocity vc of 25 and 150 m/min is applied. The evaluation of the manufacturing process is carried out by detailed analyses of the microstructural conditions in the surface layer after processing using a Focused Ion Beam system. These material characterizations provide information about the surface engineering concerning the microstructural changes in the workpiece surface layer due to machining. Hereby, the grain size analysis is investigated by a line method based on the characterization of portions of several test-lines positioned across the two dimensional Focused Ion Beam images.

[ 32 ] Schulze, V.; Zanger, F. & Hoppen, P. (2014), „How to teach design for manufacturability at micro scale tasks“. 15th International Conference on Engineering and Product Design Education, 05.09.2013-06.09.2013, Dublin, Irland, Proceedings of E&PDE 2013, Hrsg. Lawlor, J.; Reilly, G.; Simpson, R.; Ring, M.; Kovacevic, A.; McGrath, M.; Ion, W.; Tormey, D.; Bohemia, E.; McMahon, C. & Parkinson, B., S. 58-63.
Abstract:
Designing for manufacturability is a big challenge for every designer. Every manufacturing process has its characteristics and its limits. Costs and manufacturing time are often difficult to estimate, especially for engineers who do not cope with the daily problems of production processes. The relative tolerances are much higher when manufacturing on micro scale than on macroscopic scale and the production processes are generally less stable. An increasing number of products in different industries possess micro geometries and this trend will continue. Therefore the competence to design micro systems for manufacturability is getting more and more important for the next generation of designers. The wbk Institute of Production Science at the Karlsruhe Institute of Technology (KIT) is researching manufacturing processes on micro scale for more than 10 years. The institute is investigating processes such as micro milling, micro electric discharge machining, micro laser ablation and micro powder injection molding presently and will pursue this in future. Besides this research work the education of students in this field does have a high priority. Since about 10 years students are taught the basics of micro production processes and designing micro systems. Within the program of engineering studies a master course that comprises theory and application of micro systems is offered. This course consists of several lectures on the manufacturing processes at wbk and project work with one of the institute’s industry partners. This assures that the students get acquainted with the present problems of manufacturing on micro systems in the industry. Furthermore they learn designing for manufacturability as it is required in real world manufacturing processes.

[ 33 ] Schulze, V.; Zanger, F.; Boev, N.; Michna, J.; Maas, U. & Faltin, C. (2014), „FE-Simulation of Machining Induced Phase Transformations Considering Friction as a Function of Temperature and Sliding Speed and Detailed Modeling of the Heat Transport“, Advanced Engineering Materials, Band 16, Nr. 2, S. 137-141. DOI: 10.1002/adem.201300103
Abstract:
2D-FE-cutting simulation for the steel 42CrMo4 (AISI4140) including the prediction of machining induced phase transformations at the workpiece surface layer. The model predicts thickness, composition and hardness of transformed workpiece material.

[ 34 ] Schulze, V.; Zanger, F. & Hoppen, P. (2014), „Broaching“, CIRP Encyclopedia of Production Engineering, S. 1-12.
Abstract:


[ 35 ] Ambrosy, F.; Zanger, F.; Schulze, V. & Jawahir, I. (2014), „An Experimental Study of Cryogenic Machining on Nanocrystalline Surface Layer Generation “. 2nd CIRP Conference on Surface Integrity (CIRP CSI), 28.05.2014-30.05.2014, Nottingham, United Kingdom, Procedia CIRP 13, Hrsg. Prof. Dragos Axinte, S. 169-174.
Abstract:
This paper presents an analysis of in-process liquid nitrogen cryogenic cooling on the generation of nanocrystalline workpiece (AISI4140) surface layer in machining. Samples from cryogenic machining demonstrate nanocrystalline grain refinement with beneficial properties, e.g., favorable wear characteristics. Correlations are established among process and geometry parameters, cooling conditions, cutting forces and surface layer states. Parameters studied are cooling state, depth of cut and cutting edge radius. Cutting forces are measured and a detailed analysis of micro/nano-structural surface layer conditions was carried out using Focused Ion Beam system, Atomic Force Microscopy and Nanoindentation. It is shown that the obtained micro/nano- structure strongly depends on the cooling conditions. In particular, the affected depth is influenced by the cooling state.

[ 36 ] Klotz, S.; Gerstenmeyer, M.; Zanger, F. & Schulze, V. (2014), „Influence of Clamping Systems During Drilling Carbon Fiber Reinforced Plastics “. 2nd CIRP Conference on Surface Integrity (CIRP CSI), 28.05.2014-30.05.2014, Nottingham, United Kingdom, Procidia CIRP, Hrsg. Axinte, D., S. 208-213.
Abstract:
During postprocessing of carbon fiber reinforced plastics, drilling is one of the mostly used machining processes. With increasing complexity of components the requirements on the clamping systems are rising. This paper shows the investigation of drilling tests fordifferent types of clamping positions which are examined regarding their influence on the resulting workpiece quality. The clamping of the planar specimens was realized by 3 and 4 points and by a ring clamping system with variable distances from the drill axis to the fixed points. During the experiments the process forces were measured and the resulting delamination and fiber pullouts at the workpiece surface were determined. The results demonstrate that the distance from the drill axis to the fixed points has a significant influence on the process forces and the achievable workpiece quality.

[ 37 ] Hoppen, P.; Zanger, F. & Schulze, V. (2014), „Aktive Kompensation des Schneidkantenversatzes“, Mikroproduktion, S. 58-62.
Abstract:
In der Mikrozerspanung haben kleinste Rundlauffehler große Auswirkkungen auf die Standzeiten des Werkzeugs und das Bearbeitungsergebnis. Neue Perspektiven für die hochpräzise Mikrobearbeitung bietet jetzt das WERKZEUGSPANNSYSTEM >µChuck<, das den Versatz der Schneidkante µm-genau kompensiert.

[ 38 ] Zanger, F.; Boev, N. & Schulze, V. (2014), „Surface Quality after Broaching with Variable Cutting Thickness “. 2nd CIRP Conference on Surface Integrity (CIRP CSI), 28.05.2014-30.05.2014, Nottingham, United Kingdom, Procedia CIRP 13, Hrsg. Prof. Dragos Axinte, S. 114-119.
Abstract:
During machining, new surfaces are generated. Depending on the machining process, different qualities of surfaces are produced. After broaching, a high surface quality is expected. However, the quality can be influenced by vibrations of the machine structure which leads to varying cutting thicknesses and thus to low surface qualities. The influence of variable cutting thicknesses during machining was investigated experimentally and by means of simulations. Dynamic changes in cutting thickness were considered as geometrical profiles on the uncut surfaces. Process forces were measured during the experiments and the roughness before and after broaching with one tooth was evaluated. The residual stresses in the workpiece surfaces were simulated with an already validated model of orthogonal machining using a self-implemented re-meshing method.

[ 39 ] Fleischer, J.; Schulze, V.; Zanger, F.; Leberle, U.; Boev, N. & Spohrer, A. (2014), „Spanntechnikvergleich bei der Hochleistungszerspanung“, VDI-Z, Band 2, S. 42-44. [02.04.16].
Abstract:
In einer Studie wurden am wbk - Institut für Produktionstechnik Werkzeughaltersysteme in Hydro-Dehnspanntechnik und Warmschrumpftechnik vergleichend gegenübergestellt. Der Fokus lag auf den bei der Hochleistungszerspanung bedeutsamen Kriterien Produktivität und Werkzeugstandzeit.

[ 40 ] Zanger, F. & Gerstenmeyer, M. (2014), „Material Behaviour of Armco-Iron and AISI 4140 at High Speed Deformation during Machining“. WGP Congress 2014, 09.09.2014-10.09.2014, Erlangen, Deutschland, WGP Congress 2014, Hrsg. Trans Tech Publications, S. 161-166.
Abstract:
During machining of metals high temperatures and deformations occur at the surface layers leading to changing component states. Depending on the thermal and mechanical set of stress microstructural changes like residual stresses and grain refinement can be found. Grain refinement is influenced by the amount of deformation. In the present investigations high deformations of the surface layers are realized by using the cutting tool in opposed direction resulting in high negative rake angles. This test setup is used to investigate the material behaviour of Armco-Iron and AISI 4140 at different cutting velocities during machining. Furthermore the flow stresses at different strain rates and temperatures were determined by means of high speed tensile tests. The flow behaviour of the investigated materials is used to explain the results of the machining experiments.

[ 41 ] Klotz, S.; Zanger, F. & Schulze, V. (2014), „Influence of clamping systems during milling of carbon fiber reinforced composites“. New Production Technologies Aerospace Industry - 5th Machining Innovations Conference (MIC 2014), 19.11.2014-20.11.2014, Hannover, Deutschland, New Production Technologies in Aerospace Industry, Hrsg. Prof. Dr.-Ing. Berend Denkena, S. 248-256.
Abstract:
Carbon fiber reinforced composites (CFRP) are mostly manufactured near net shape. Nevertheless, a final milling step at the edges of the cured components is still necessary. Damages which occur during milling or drilling of CFRP lower the durability of the components and increase the production costs. Requirements concerning the clamping system for milling or drilling CFRP are rising simultaneously with increasing complexity of the components. This stresses the need for complex clamping systems like linear clamping jaws around the whole workpiece. However such types of clamping systems induce poor accessibility to the component being worked on and hence longer machining time. As a result to the need for complex clamping systems, the production costs are increased. Therefore, several benefits can be achieved by increasing the distances between the clamping points of the clamping system to reduce machining time and production costs. This paper discusses investigations of milling tests with variable clamping conditions of the workpieces. In the experiments a linear milling operation the edge of the workpiece is examined. The clamping of the planar specimens was realized with a clamping system which enables the adjustment of different distances between the clamping points of the specimen. The process forces and the resulting damage at the workpiece surfaces were measured during the experiments. These results are compared with a linear clamping system to examine the influence of rising clamping distances. The results demonstrate that the distance of the clamping points while milling the edge of the workpiece has a significant influence on the process forces.

[ 42 ] Klotz, S.; Zanger, F. & Schulze, V. (2014), „Influence of Clamping Systems during Milling of Carbon Fiber Reinforced Composites “, Procedia CIRP, S. 38-43. http://dx.doi.org/10.1016/j.procir.2014.07.142
Abstract:
Carbon fiber reinforced composites (CFRP) are mostly manufactured near net shape. Nevertheless, a final milling step at the edges of the cured components is still necessary. Damages which occur during milling or drilling of CFRP lower the durability of the components and increase the production costs. Requirements concerning the clamping system for milling or drilling CFRP are rising simultaneously with increasing complexity of the components. This stresses the need for complex clamping systems like linear clamping jaws around the whole workpiece. However such types of clamping systems induce poor accessibility to the component being worked on and hence longer machining time. As a result to the need for complex clamping systems, the production costs are increased. Therefore, several benefits can be achieved by increasing the distances between the clamping points of the clamping system to reduce machining time and production costs. This paper discusses investigations of milling tests with variable clamping conditions of the workpieces. In the experiments a linear milling operation the edge of the workpiece is examined. The clamping of the planar specimens was realized with a clamping system which enables the adjustment of different distances between the clamping points of the specimen. The process forces and the resulting damage at the workpiece surfaces were measured during the experiments. These results are compared with a linear clamping system to examine the influence of rising clamping distances. The results demonstrate that the distance of the clamping points while milling the edge of the workpiece has a significant influence on the process forces.

[ 43 ] Zanger, F.; Fellmeth, A.; Gerstenmeyer, M. & Schulze, V. (2015), „Influence of Kinematic Hardening during Machining of ARMCO Iron“. 15th CIRP Conference on Modelling of Machining Operations (15th CMMO), 11.06.2015-12.06.2015, Karlsruhe, Deutschland, Procedia CIRP, Hrsg. Schulze, V., S. 106-111.
Abstract:
The simpler implementation of isotropic hardening begs the question, if modelling kinematic hardening is necessary, especially if the hardening is nonlinear and temperature dependent. This question not only depends on the material, but also on the modelled load case, which varies with different manufacturing processes. To answer this, thermo-mechanically coupled elasto-plastic materials were used in an implicit material model in ABAQUS/Standard for a two-dimensional cutting simulation. The nonlinear hardening in the models varies from isotropic to mixed isotropic-kinematic hardening. The two-dimensional cutting simulation uses a two-dimensional continuous remeshing technique. A slow machining process was simulated leaving out strain rate and temperature dependencies and focussing purely on the kinematics of deformation. The necessity of a kinematically translated yield surface is concluded for iron, by comparing the purely isotropic to the mixed isotropic-kinematic hardening results. A comparison with experimental data illustrates the conformance quality of the different hardening modes.

[ 44 ] Zanger, F.; Boev, N. & Schulze, V. (2015), „Novel Approach for 3D Simulation of a Cutting Process with Adaptive Remeshing Technique “. 15th CIRP Conference on Modelling of Machining Operations (15th CMMO), 11.06.2015-12.06.2015, Karlsruhe, Deutschland, Procedia CIRP 31, Hrsg. Volker Schulze, S. 88-93.
Abstract:
This paper presents an approach of a 3D cutting simulation with a continuous adaptive remeshing technique. Such a method allows the investigation of cutting processes without losing precious information. Furthermore, the developed 3D remeshing technique represents a possibility to investigate the effects caused by the secondary cutting edge in detail for more complex cutting processes. When a 3D model is built up to simulate the cutting process, an accurate meshing of the workpiece and the cutting edge is applied, which means that a large number of elements is generated. The presented remeshing method is applied only locally at regions, where distorted elements are located. This leads to a significant reduction of the calculation times compared to other remeshing techniques.

[ 45 ] Ambrosy, F.; Zanger, F. & Schulze, V. (2015), „FEM-simulation of machining induced nanocrystalline surface layers in steel surfaces prepared for tribological applications “, CIRP Annals - Manufacturing Technology, Band 64, Nr. 1, S. 69-72. http://dx.doi.org/10.1016/j.cirp.2015.04.063
Abstract:
A formation of nanocrystalline grains due to dynamic recrystallization within the workpiece surface layer (AISI4140) resulting from machining has proven to be suitable for obtaining improved tribological and fatigue behaviour. In the work presented an optimization of the machining process is carried out with cutting simulations using a continuous remeshing method and describing surface layer generation. The simulations describe the influence of process parameters and tool geometry on evolution of grain size distributions within the subsurface and affected depth after this thermo-mechanical processing. The validation is performed by experimental analyses based on cutting technology and focused ion beam technique.

[ 46 ] Bejnoud, F.; Zanger, F. & Schulze, V. (2015), „Component Distortion due to a Broaching Process“. WGP Jahreskongress, 07.09.2015-08.09.2015, Hamburg, Deutschland, Progress in Production Engineering, Hrsg. Trans Tech Publications, S. 239-246.
Abstract:
In order to obtain a better understanding of the effects of an internal broaching operation on the resulting component geometry, investigations were carried out. The investigations were carried out on sliding sleeves made of case hardening steel SAE 5115 (German grade 16MnCrS5). The cutting speed was varied. The results indicate that the arrangement of teeth on the scope of the tool has a significant influence on the resulting component geometry. Furthermore the results show that also the cutting speed has a significant influence on the resulting component geometry, in particular due to the resulting process temperatures.

[ 47 ] Schoop, J.; Ambrosy, F.; Zanger, F.; Schulze, V.; Jawahir, I. S. & Balk, T. J. (2016), „Increased Surface Integrity in Porous Tungsten from Cryogenic Machining with Cermet Cutting Tool“, Materials and Manufacturing Processes, Nr. 7, S. 823-831. 10.1080/10426914.2015.1048467
Abstract:
In order to eliminate the process of backfilling porous tungsten with a plastic infiltrant during machining to prevent unwanted smearing of surface pores, cryogenic machining is investigated as a viable alternative. Porous tungsten is mainly used in the manufacture of dispenser cathodes where demands for surface quality and dimensional tolerances are extremely high. For these reasons, the ability of cryogenic machining to provide increased surface integrity and tool life compared to conventional dry machining is explored. Moreover, some preliminary results of machining with various cutting edge radii and effects on surface stress state are presented. Overall, cryogenic machining does provide significant surface quality and tool wear improvements over conventional dry machining practices.

[ 48 ] Schoop, J.; Ambrosy, F.; Zanger, F.; Schulze, V.; Balk, T. J. & Jawahir, I. S. (2016), „Cryogenic machining of porous tungsten for enhanced surface integrity “, Journal of Materials Processing Technology, S. 614-621. http://dx.doi.org/10.1016/j.jmatprotec.2015.10.002
Abstract:
Abstract Cryogenic machining of porous tungsten is being developed as an alternative sustainable process to current industry practice of machining plastic infiltrated workpieces. Eliminating the use of plastic infiltrant is contingent on the ability to control as-machined surface properties of porous tungsten. To this end, the influence of various machining parameters and cooling conditions on machining mechanisms, particularly as a function of cutting temperature, is explored. By employing modified polycrystalline diamond cutting tools, high speed cryogenic machining of porous tungsten by ductile shear was achieved. Cutting speeds of up to 400 m/min are possible with this novel approach, and very low surface roughness of Ra ≈ 0.4 μm is realized, at the expense of surface porosity. At low cutting speeds, rake angle has a key impact on surface morphology, with more negative rake angles increasing the amount of brittle fracture occurring on the machined surface and thereby increasing surface porosity. An excellent mix of open surface porosity and low surface roughness may be achieved at low cutting speeds of 20 m/min when a sharp edged cutting tool with a rake angle of −5° is used. Using a separate set of machining parameters for rough and finish machining may offer an optimum approach to realize economical cryogenic machining of porous tungsten.

[ 49 ] Gerstenmeyer, M.; Zanger, F. & Schulze, V. (2016), „Complementary Machining – Machining Strategy for Surface Modification“. Conference on Surface Integrity, 08.06.2016, Charlotte, North Carolina, USA, Procedia CIRP 45, Hrsg. Elsevier, S. 247-250.
Abstract:
In metal production mechanical surface treatments are used to optimize workpiece characteristics like fatigue strength. Complementary Machining is a new machining strategy which is characterized by the combination of cutting and mechanical surface treatment. After cutting the insert is used reversely acting as a tool for mechanical surface treatment. This paper shows the effect of high plastic deformation rates in the surface layer reducing surface roughness and increasing strain hardening. Furthermore, it is supposed that the process induces grain refinement in the surface layer. The process strategy Complementary Machining is investigated during machining Armco-Iron and AISI 4140.

[ 50 ] Schulze, V.; Bollig, P.; Gerstenmeyer, M.; Segebade, E. & Zanger, F. (2016), „Surface Engineering - Optimierte Oberflächen durch Zerspanungsprozesse“, mav Innovationsforum 2016, S. 6-8.
Abstract:
Bei der spanenden Bauteilherstellung ändern sich die Zustände der bearbeiteten Oberflächen durch hohe mechanische und thermische Belastungen maßgeblich. Diese Änderungen wirken sich neben topologischen Zuständen wie Rauheiten auf mechanische Zustände wie Eigenspannungen oder Verfestigungen und auf metallographisch erfassbare Zustände wie Phasenumwandlungen oder Änderung der Mikrostruktur aus. Mit Hilfe neuer Kenntnisse über die Wechselwirkungen zwischen Prozessen und Bauteilen werden am wbk Institut für Produktionstechnik in enger Zusammenarbeit mit dem Institut für angewandte Materialien-Werkstoffkunde (IAM-WK) mittels Surface Engineering die Eigenschaften von Bauteilen definiert eingestellt. Hierbei stehen besonders Charakteristika der Bauteilrandzonen, wie Eigenspannungs- und Verfestigungszustände, im Vordergrund, die durch den Fertigungsprozess bestimmt werden und einen großen Einfluss auf die Eigenschaften bei schwingender oder tribologischer Beanspruchung besitzen. Die definierte Erzeugung von Bauteilrandzonen, aber auch die schädigungsarme Bearbeitung, spielt dabei eine große Rolle. Am wbk werden zerspanungsbedingte Bauteilzustände und –eigenschaften in verschiedenen Forschungsprojekten zusätzlich zu den experimentellen Untersuchungen mittels Prozesssimulationen analysiert, um damit zu einer numerisch unterstützten Optimierung des Zerspanungsprozesses zu gelangen.

[ 51 ] Bollig, P.; Köhler, D.; Zanger, F. & Schulze, V. . (2016), „Effects of different levels of abstraction simulating heat sources in FEM considering drilling“. 7th HPC 2016 – CIRP Conference on High Performance Cutting, 31.05.2016, Chemnitz, Deutschland, Procedia CIRP, Hrsg. Elsevier, S. 115-118.
Abstract:
This paper presents a comparison of three different methods of simulating heat sources in 3D-FEM-simulations with various levels of abstraction for drilling. The investigated methods are modelled and evaluated with respect to calculation time and accuracy of simulated temperature fields and phase transformations. Results are showing a significant variance of the maximum temperature and temperature distribution for the three different heat sources although the same amount of energy is used in the simulation model. According to the longest simulation time the most detailed heat source provides a realistic temperature distribution.

[ 52 ] Bollig, P.; Wengle, D.; Schulze, V. & Zanger, F. . (2016), „Analyse der MMS-Zerspanung zur Aerosolbeurteilung“, Maschinenmarkt, S. 32-35.
Abstract:
Basierend auf Untersuchungen zur Charakterisierung von Minimalmengenschmiersystemen [MMS] soll es möglich werden, das Zusammenspiel von einzelnen Komponenten für MMS-Systeme, wie Werkzeugen oder MMS-Geräten, bewerten.

[ 53 ] Fleischer, J.; Schulze, V.; Klaiber, M.; Bauer, J.; Zanger, F.; Boev, N.; Leberle, U.; Spohrer, A. & Rothaupt, B. (2016), „The influence of tool holder technologies on milling performance “. 7th HPC 2016 – CIRP Conference on High Performance Cutting, 31.05.2016-02.06.2016, Chemnitz, Deutschland, Procedia CIRP 46 ( 2016 ), Hrsg. ELSEVIER, S. 226-229.
Abstract:
The quality of machined surfaces is significantly influenced by machine vibrations caused by the cutting process. Whereas most publications ignore the influence of the tool holder, this paper considers the dynamic behaviour of the whole cutting system consisting of spindle, tool holder, tool and workpiece. Therefore modal and operational vibration analyses were performed to describe the damping and operational characteristics of two competing tool holder technologies, namely heat shrink (HS) and hydraulic expansion (HE). It is shown that HE has higher damping rates than HS. Therefore, HE showed mainly better surface qualities, a 10 % higher productivity and an up to 300 % higher achievable life time of tools.

[ 54 ] Segebade, E.; Zanger, F. & Schulze, V. (2016), „Influence of Different Asymmetrical Cutting Edge Microgeometries on Surface Integrity“. CIRP Conference on Surface Integrity, 08.06.2016, Charlotte, North Carolina, USA, Procedia CIRP 45, Hrsg. Elsevier, S. 11-14.
Abstract:
The importance of cutting edge microgeometries in machining operations has been proven time after time again. Not only with regard to wear, but also as an important factor influencing the resulting surface integrity. In this paper the influence of asymmetric cutting edge microgeometries and different process parameters on the resulting accumulated plastic strain, plastic strain rates and surface layer microstructure of AISI 4140 in cutting experiments and FE-simulations is investigated. To characterize the cutting edge microgeometries a recently published method considering the process parameters such as cutting angles is used.

[ 55 ] Matuschka, B.; Boev, N.; Zanger, F. & Schulze, V. (2016), „Simulation based reduction of the impact load occurring in the moment of cutting edge entrance in order to prolong tool-life“. WGP Jahreskongress 2016, 05.09.2016-06.09.2016, Hamburg, Deutschland, Applied Mechanics and Materials, Hrsg. TPP, S. 112-118.
Abstract:
High mechanical impact loads in interrupted or inhomogeneous machining processes frequently lead to spontaneous fracture of the cutting edge. Even modern cutting materials cannot provide a combination of hardness and toughness that is capable of preventing this sort of tool failure. Such machining conditions therefore remain difficult, and further investigations aiming to reduce the impact load of the cutting tool in order to enhance tool-life are necessary. A simulation model of the impact situation, that serves to optimize a force conducting structure with regard to elasticity, damping properties and resulting force peaks, was developed and is presented in this paper. Furthermore, measurement devices were composed that are needed for high-resolution recording of impact forces without repercussions and for verification of the elaborated simulation model. It could be shown that mechanical damping of the cutting tool can lead to reduced impact forces on the cutting edge, which in turn should lead to longer tool life.

[ 56 ] Bejnoud, F.; Zanger, F. & Schulze, V. (2016), „Influence of a high speed broaching and case-hardening process on the resulting component geometry“. 13th International Conference on High Speed Machining, 04.10.2016-05.10.2016, Metz, Frankreich, 13th International Conference on High Speed Machining, Hrsg. Tbd., S. 6.
Abstract:
In this study the effects of a case hardening process on the resulting component geometry considering the pre-process broaching is examined for sliding sleeves made of case hardening steel SAE 5115. The results indicate a significant influence of the initial state of the components on the resulting component contour after heat treatment. Particularly deviations from the ideal contour of the components due to a previous internal soft broaching process with different cutting speeds influence the resulting component contour. Near surface phase transformations during soft broaching at high cutting speeds are identified as a further influence on the resulting component contour.

[ 57 ] Klotz, S.; Zanger, F.; Sellmeier, V. & Schulze, V. (2017), „Signifikant Leistungsfähiger - synchroner Drehwirbel-Prozess“, WB Werkstatt + Betrieb, Nr. 12, S. 62-65.
Abstract:
Ein Gemeinschaftsprojekt des wbk Karlsruhe mit den Firmen Index, Paul Horn und Smith & Nephew belegt: Das parallele Wirbeln und Drehen von Gewinden eröffnet Zerspanern ein großes Potenzial hinsichtlich Fertigungszeit und Oberflächengüte der Gewindegeometrien

[ 58 ] Gerstenmeyer, M.; Segebade, E.; Zanger, F. & Schulze, V. (2017), „Simulation der mechanischen Oberflächenbehandlung mit Simufact Forming“. Roundtable Simulating Manufacturing, 30.05.2017-01.06.2017, Marburg, Deutschland, 18. Roundtable Simulating Manufacturing, Hrsg. Dr. Hendrik Schafstall und Michael Wohlmuth, S. 180-189.
Abstract:
Zur spanenden Herstellung metallischer Bauteile sind mehrere Prozessschritte erforderlich. Diese sind bspw. ausgehend vom Halbzeug über Schrupp-Schlicht-Strategien bis hin zum Surface- Finishing. Bei der Schrupp-Schlicht-Strategie folgt einer Zerspanung mit vergleichsweise hohen Schnitttiefen eine Endbearbeitung mit weitaus geringerer Schnitttiefe und angepassten Prozessparametern. Eine Möglichkeit zum Surface-Finishing ist die sog. Komplementärzerspanung. Dabei erfolgt nachfolgend zur Zerspanung eine mechanische Oberflächenflächenbehandlung mit dem eigentlichen Schneidwerkzeug. Charakteristisch ist, dass die Bearbeitungsrichtungen von Zerspanung und Oberflächenbehandlung entgegengesetzt erfolgen. Jeder dieser Prozessschritte beeinflusst die Bauteilzustände in der Randschicht. Die simulative Betrachtung von vorhergehenden Prozessen und der damit einhergehenden Änderung der Randschichtzustände ist für das Prozessverständnis ein elementarer Bestandteil, um optimale Bearbeitungsergebnisse und damit Bauteileigenschaften zu erhalten. Neben der reinen Beschreibung der Fertigungsprozesse muss für eine ganzheitliche Prozessbeschreibung auch das elasto-plastische Materialverhalten mittels geeigneter Materialmodelle beschrieben werden. In dieser Arbeit werden aufbauend auf 2D- und 3D-Spanbildungssimulationen in Simufact Forming eine Mehrfachzerspanung (Schrupp-Schlicht- Strategie) sowie die Komplementärzerspanung vorgestellt. Neben der Betrachtung der Schneidkantenmikrogeometrie stehen auch die resultierenden Randschichtzustände im Mittelpunkt der Untersuchungen.

[ 59 ] Segebade, E.; Gerstenmeyer, M.; Zanger, F. & Schulze, V. (2017), „Zerspanungssimulation mit Simufact Forming“. Roundtable Simulating Manufacturing, 30.05.2017-01.06.2017, Marburg, Deutschland, 18. Roundtable Simulating Manufacturing, Hrsg. Dr. Hendrik Schafstall und Michael Wohlmuth, S. 116-127.
Abstract:
Spanbildungsvorgänge an metallischen Bauteilen, wie beispielsweise der Drehprozess, sind gekennzeichnet durch ein thermo-mechanisches Lastkollektiv, welches während des Prozesses auf die der Schneidkante sowie auf das Bauteil und den Span einwirkt. Der Einfluss hoher Temperaturen, Dehnraten und Dehnungen müssen für Werkstoffe charakterisiert werden, um in der Simulation ein realistisches Materialverhalten abzubilden. Dabei stellen auch unsichere Kenntnisse über die Reibungsverhältnisse im realen Prozess eine Herausforderung für die Modellierung dar. Hinzu kommt die Notwendigkeit einer stabilen und effizienten Neuvernetzungs- oder Trennungsroutine zur Realisierung der Spanbildung. Für die Simulation spanabhebender Fertigungsprozesse haben sich aufgrund dieser Umstände in den letzten Jahren geeignete Softwarepaketen international etabliert. Die Eignung der Software Simufact Forming wurde im Rahmen aktueller Arbeiten sowohl für 2D- als auch für 3D-Spanbildungssimulationen demonstriert und anhand von experimentell ermittelten Kräften validiert. Dabei fand auch die Schneidkantenmikrogeometrie Beachtung. Die Mikrogeometrie nimmt nachweislich Einfluss auf die Prozesskräfte sowie die zerspanungsbedingten Randzonenzustände, wie die Gefügestruktur und Eigenspannungsverteilung.

[ 60 ] Schulze, V.; Zanger, F.; Bollig, P.; Segebade, E.; Gerstenmeyer, M. & Klotz, S. (2017), „Randschichtzustände nach Fertigungsprozessen – Erzeugung und Bewertung“ in Moderne Zerspanungstechnologie - Neue Entwicklungen und trends aus der Forschung und Praxis, Hrsg. Azarhoushang, B. & Wolf, T., Hochschule Furtwangen, Villingen-Schwenningen, S. 1-7.
Abstract:
Die spanende Bearbeitung von metallischen Werkstoffen besitzt in der produzierenden Industrie einen hohen Stellenwert. Dabei beeinflusst der spanende Endbearbeitungsprozess mit mechanischer und thermischer Wechselwirkung zwischen Werkstückstoff und Werkzeug die finalen Bauteilzustände. Dabei spielen neben Oberflächenrauheit oder geometrischen Toleranzen auch die Eigenspannungen und Verfestigungen eine wichtige Rolle. Mit Surface Engineering wird die gezielte Prozesssteuerung zur Beeinflussung des Bauteilverhaltens bezüglich der Schwingfestigkeit, der tribologischen Eigenschaften sowie der entstehenden Phasenumwandlungen oder der Mikrostruktur bezeichnet. Unter diesem Gesichtspunkt werden am wbk Institut für Produktionstechnik in Zusammenarbeit mit dem Institut für angewandte Materialien – Werkstoffkunde (IAM-WK) neue Fertigungsprozesse entwickelt sowie bestehende Prozesse optimiert. Hierbei werden in Forschungsprojekten experimentelle und simulationsgestützte Methoden angewandt, um das Prozessverständnis zu erhöhen und die geforderten Eigenschaften zu erzielen. Ausgewählte Themen sind die Untersuchung von Werkzeugverschleiß und Randschichtzuständen bei der Bearbeitung schwer zerspanbarer Materialien, die Phasenumwandlung bei der Trockenbearbeitung und der Minimalmengenschmierung (MMS), die Erzeugung von nanokristallinen Randschichten in Abhängigkeit der Schneidkantenmikrogeometrie und auch die am Institut entwickelte Prozessstrategie Komplementärzerspanung.

[ 61 ] Segebade, E.; Zanger, F. & Schulze, V. (2017), „Asymmetrische Schneidkantenmikrogeometrien - Bedeutung, Charakterisierung, potenzielle Anwendungen und Herausforderungen“ in Spanende Fertigung, Hrsg. Dirk Biermann, Vulkan Verlag, Essen, S. 79-85. ISBN/ISSN: 978-3-8027-2989-8
Abstract:
In der Zerspanung wird der Schneidkantenmikrogeometrie bereits seit Jahren ein hoher Stellenwert zugesprochen. Neben der anfänglichen Überlegung, durch gezielte Schneidkantenpräparation die Standzeit von Werkzeugen zu erhöhen, wurde in den letzten Jahren insbesondere das Potential betreffend der Ausbildung von Bauteilrandschichten untersucht. In beiden Fällen ist auch die vergleichbare Charakterisierung von Schneidkanten auf der µm-Skala Ziel vieler Untersuchungen geworden. In diesem Beitrag wird der Stand der Forschung asymmetrischer Schneidkantenmikrogeometrien insbesondere bezüglich der Charakterisierung fokussiert, sowie auf potentielle Anwendungen und Herausforderungen bei derselben eingegangen. In diesem Zuge werden zur Verdeutlichung Daten aus aktueller experimenteller Forschung herangezogen.

[ 62 ] Gerstenmeyer, M.; Ort, B.; Zanger, F. & Schulze, V. (2017), „Influence of the cutting edge microgeometry on the surface integrity during mechanical surface modification by Complementary Machining“. Conference on Modelling of Machining Operations, 15.06.2017-16.06.2017, Cluny, Frankreich, Procedia CIRP, Hrsg. Elsevier, S. 55-60.
Abstract:
In metal production, mechanical surface modifications are used to optimize workpiece characteristics to improve properties such as fatigue strength. Machining and mechanical surface modification can be integrated in the process strategy Complementary Machining. After machining the cutting tool is used reversely acting as a tool for mechanical surface modification. This paper shows the influence of the cutting edge microgeometry on process forces and temperatures as well as process induced grain refinement in the surface layer during the mechanical surface modification of Armco-Iron and AISI 4140. The mechanical surface modification is simulated in a 3D-FEM-simulation with ABAQUS/Standard.

[ 63 ] Segebade, E.; Gerstenmeyer, M.; Zanger, F. & Volker, S. (2017), „Cutting Simulations Using a Commercially Available 2D/3D FEM Software for Forming“. Converence on Modelling of Machining Operations, 15.06.2017-16.06.2017, Cluny, Frankreich, Procedia CIRP, Hrsg. Elsevier, S. 73-78.
Abstract:
Chip formation simulations require either sophisticated material based element removal or deactivation routines, or a powerful remeshing procedure. Therefore the accuracy of all chip formation simulations significantly depends on the FEM-software as well as the material data. Over the course of the past years, a few select commercial programs became the pre-eminent choice for chip formation simulations. In this work, the software simufact.forming, which is not one of those few programs widely in use, has been employed for 2D and 3D chip formation simulations. Orthogonal cutting experiments with AISI4140 were conducted and subsequently modeled, including the cutting edge radius. The results were analyzed with regard to how well chip formation and the resulting process forces in 2D and 3D can be depicted.

[ 64 ] Zanger, F.; Sellmeier, V.; Klose, J.; Bartkowiak, M. & Schulze, V. (2017), „Comparison of Modeling Methods to Determine Cutting Tool Profile for Conventional and Synchronized Whirling“. Conference on Modelling of Machining Operations (CMMO), 15.06.2017-16.06.2017, Cluny, Frankreich, Procedia Cirp, Hrsg. Elsevier, S. 222-227.
Abstract:
The determination of cutting tool profiles for machining operations with coupled rotational kinematics like gear and screw generation can be a complex task which is executed by either numerical or analytical methods. The cutting tool profile for whirling is derived from process parameters and desired workpiece geometry by both a numerical dexel-based model and an analytical model based on the condition of tangential motion. The models are adapted to a process variant of whirling with synchronized rotation of tool and workpiece and compared regarding accuracy, computation time and geometrical flexibility.

[ 65 ] Zanger, F.; Gerstenmeyer, M. & Weule, H. (2017), „Identification of an optimal cutting edge microgeometry for Complementary Machining“, CIRP Annals - Manufacturing Technology, S. 81-84.
Abstract:
The process strategy Complementary Machining combines machining and surface modification, resulting in optimal workpiece properties like fatigue strength. Right after machining the cutting tool is used reversely acting as a tool for a mechanical surface modification. The challenge of designing a cutting edge microgeometry that withstands the load spectrum and induces optimal surface layer states during Complementary Machining is solvable by modeling the resulting surface layer using FEM-simulation. Using the simulation-based analyses a deep process understanding is accomplished enabling further optimization of surface integrity (e.g. grain refinement) which is proven by measurements.