Thermography in incremental forming processes at elevated temperatures

Temperature measurement is essential for several forming processes at elevated temperatures. It serves to determine and control the workpiece temperature. Thermography as a non-contact-based technology offers the possibility to capture thermograms of complete workpieces without any time-offset. However, the application of thermography requires the knowledge of the fundamentals of radiation thermometry, in particular the emissivity. This paper presents the results of the application of thermography in incremental sheet forming (ISF) with Joule heating and radial–axial ring rolling as a bulk forming process. Using thermography for the determination of the temperature of the forming zone allows for a real-time closed loop control in ISF with Joule heating. Additionally, the results of the temperature measurement of the surface temperature of radial–axial rolled rings are presented, which can be used as a starting point to make a forecast of the rings’ dimensions in cold state.