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- Kledwig, Christian, et al.
(author)
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A Study on the accuracy of Thermography-based Temperature measurement in Powder-fed directed energy deposition
- 2020
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In: 20th CIRP Conference on Electro Physical and Chemical Machining. - : Elsevier. ; , s. 35-41
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Conference paper (peer-reviewed)abstract
- Due to continuous development and increasingly deep understanding of the additive process, directed-energy deposition (DED) is becoming more and more interesting for industrial use. However, both the number of influencing factors and the process complexity, still require well-trained operators who can monitor and understand the machine tools. In order to facilitate the operators and to enable longer unattended processes, higher process safety, reliable monitoring systems and closed-loop controller are required. For example, despite a large number of investigations, the monitoring and control of the temperature distribution within the work piece still poses a big challenge.This study focusses on workpiece temperature measurement using a thermal imaging camera that observes the entire machining area. In order examine the measurement error caused by different viewing angles (φ = 0 … 75°), object temperatures (T = 333 … 1073K), surface conditions (welded and milled) and materials (316L, Inconel 718 and CuAl10) commonly used in DED, several approaches were followed using a thermal camera.It was found that surface condition and material cause the greatest measuring errors (up to +325K |−453K).). However, the measuring errors can be significantly reduced by suitable selection of the emissivity, so that it is possible to measure even the milled CuAl10 surface at a known viewing angle with a measuring error of +13.3% |−10.9%.
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