Titel Wear detection through measurement of the thermoelectrical current and electrical resistance
Autor Yutian Wu, Chen Chen, Peter Groche
Infos zum Autor Yutian Wu; Chen Chen; Peter Groche
Yutian Wu M. Sc.1, Chen Chen M. Sc.1, Prof. Dr.-Ing. Dipl.-Wirtsch.-Ing. Peter Groche1
1Technische Universität Darmstadt – Institute for Production Engineering
and Forming Machines
Otto-Berndt-Straße 2
64287 Darmstadt, Germany
Telefon: +49(0)6151 16-23314 Mail: wu@ptu.tu-darmstadt.de
Inhalt Increasing demand of high strength steels within the forming industry leads to new challenges for the tribological process design. For example, the oil film of the tribological system used for high strength steels tends to fail in earlier forming steps compared to the system used for mild sheet metal. Also, this accelerated wear development leads to abrupt failures of forming tools such as tools for deep drawing and stretch forming, which are of high economic relevance. In order to increase the understanding of the preconditions leading to tool failure, a wear detection system with high resolution and high sensibility is necessary. A promising concept to realize such a detection system is the measurement of the electrical resistance and thermoelectrical current between base and counter body. In this approach, a measuring system is presented, which enables the determination of the electrical resistance and the thermoelectrical current between two tools and the sheet metal. The experimental investigations are conducted using a strip drawing test, which is an application oriented testing method in sheet metal forming. Several sets of tribological systems are tested, until macroscopic detectable wear occurs. During these test runs, the development of the electrical resistance and thermoelectrical current as well as the surface roughness of the sheet metal is recorded. By analyzing the evolution of the measured values throughout the entire wear development and comparing the results with other classical methods such as surface roughness and drawing force measurement, this new measuring method is evaluated. In addition, the reproducibility of the results is also discussed in this approach. The results show that wear can be detected by measuring the electrical resistance and thermoelectrical current between the forming tools and sheet metal with better sensibility and precision compared to classical measurement methods.
Datum 2018