Title: Evaluations of temperature measurements in powder-based electron beam additive manufacturing by near-infrared thermography

Authors: Steven Price; Kenneth Cooper; Kevin Chou

Addresses: Department of Mechanical Engineering, The University of Alabama, 290 Hardaway Hall, 7th Ave., Tuscaloosa, AL 35487, USA ' Advanced Manufacturing Technology Team, Marshall Space Flight Center, Mail Stop EM42, Bldg 4707, Room 142, Huntsville, AL 35812, USA ' Department of Mechanical Engineering, The University of Alabama, 290 Hardaway Hall, 7th Ave., Tuscaloosa, AL 35487, USA

Abstract: Powder-based electron beam additive manufacturing (EBAM) has received an increased attention from different industries for various applications. Process metrology such as part temperature measurements is essential to process model validations as well as process monitoring. However, temperature measurements in EBAM are challenging because of high temperature ranges, extreme gradients and fast transient response, etc. In this study, temperature measurements during the EBAM process were attempted using a near-infrared (NIR) thermal camera. The thermal camera was able to capture the pre-heating, contour melting, and hatch melting events. The best obtained spatial resolution is around 12 µm. Moreover, temperature data were processes and analysed to illustrate the process phenomenon, analogy to a moving heat source event. Moreover, from the extracted temperature profiles, a melting range can be identified and utilised for melt pool geometry estimates. It is shown that a typical melt pool in hatch melting from this test is about 1.91 mm long and 0.63 mm wide.

Keywords: EBAM; electron beam additive manufacturing; NIR; near-infrared thermography; process temperature; temperature measurements; pre-heating; contour melting; hatch melting.

DOI: 10.1504/IJRAPIDM.2014.062010

International Journal of Rapid Manufacturing, 2014 Vol.4 No.1, pp.1 - 13

Received: 25 Feb 2013
Accepted: 29 Aug 2013
Published online: 23 Oct 2014 *

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