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The influence of the process parameters on the surface integrity during peripheral milling of Ti-6Al-4V

Der Einfluss der Prozessstellgrößen auf die Oberflächenintegrität beim Umfangsfräsen von Ti 6Al 4V
Matthias Wimmer, Muhammed Zubair Shahul Hameed, Christoph Wölfle, Vanessa Weisbrodt, Michael Friedrich Zaeh, Ewald Werner, Christian Krempaszky and Thomas Semm
From the journal tm - Technisches Messen

Abstract

The titanium alloy Ti-6Al-4V represents a significant metal portion of state-of-the-art aircraft structural and engine components. When critical structural components in the aerospace industry are manufactured with the objective to reach high reliability levels, surface integrity is one of the most relevant parameters used for evaluating the quality of machined surfaces. The residual stresses and the surface alteration induced by machining titanium alloys are critical due to safety and sustainability issues. In this paper, a series of end milling experiments was conducted to comprehensively characterize the surface integrity at various milling conditions. The experimental results have shown that the surface roughness value increases with the feed and the cutting velocity. However, the residual stress state in the surface layer zone is influenced by the variation of the process control variables. Here, compressive residual stresses occur both in cutting and in feed direction. In addition, a new type of sensory tool holder is presented, which should enable the indirect measurement of residual stresses during the milling process.

Zusammenfassung

Die Titanlegierung Ti-6Al-4V wird für die Herstellung von Flugzeugstruktur- und Triebwerkskomponenten verwendet. Wenn kritische Strukturkomponenten in der Luft- und Raumfahrtindustrie mit dem Ziel hergestellt werden, ein hohes Zuverlässigkeitsniveau zu erreichen, ist die Oberflächenintegrität einer der wichtigsten Parameter, die zur Bewertung der Qualität der endbearbeiteten Oberflächen verwendet wird. Die Eigenspannungs- und die Oberflächenveränderung, die durch die Bearbeitung von Titanlegierungen auftreten, sind aufgrund von Sicherheits- und Nachhaltigkeitsaspekten kritisch. In diesem Beitrag wurde eine Reihe von Umfangsfräsversuchen durchgeführt, um die Oberflächenintegrität bei verschiedenen Fräsbedingungen umfassend zu charakterisieren. Die experimentellen Ergebnisse haben gezeigt, dass die Oberflächenrauheitswerte durch Änderungen des Vorschubs pro Zahn und der Schnittgeschwindigkeit nicht signifikant beeinflusst werden. Der Eigenspannungszustand in der Randschichtzone ist jedoch durch die Variation der Prozessstellgrößen beeinflusst. Hierbei treten Druckeigenspannungen sowohl in Schnitt- als auch in Vorschubrichtung auf. Darüber hinaus wird ein neuartiger sensorischer Werkzeughalter vorgestellt, der die indirekte Messung von Eigenspannungen während des Fräsprozesses ermöglichen soll.

Funding source: Deutsche Forschungsgemeinschaft

Award Identifier / Grant number: SPP 2086

Funding statement: The scientific work has been supported by the DFG within the research priority program SPP 2086.

Acknowledgment

The authors thank the DFG for this funding and intensive technical support.

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Received: 2020-07-20
Accepted: 2020-09-20
Published Online: 2020-10-01
Published in Print: 2020-11-26

© 2020 Walter de Gruyter GmbH, Berlin/Boston

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