Automatic Layerwise Acquisition of Thermal and Geometric Data of the Electron Beam Melting Process using Infrared Thermography

Ridwan, S.
Mireles, J.
Gaytan, S.M.
Espalin, D.
Wicker, R.B.
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University of Texas at Austin

Layerwise monitoring has become an area of interest in the field of additive manufacturing because of potential to further enable part qualification during every stage of fabrication. Spatial monitoring and qualification during part fabrication has never before been possible with traditional manufacturing processes such as milling or casting. An IR camera has been externally annexed atop an EBM system to obtain layerwise thermographs throughout the fabrication process. This paper demonstrates a process to compare each layer of fabrication using automatically acquired thermal images to the corresponding CAD file for each fabricated object. Two different methods of image analysis for part detection were compared (analysis on the basis of color and analysis by edge detection). Detection allowed the quantification of processing information (average temperature and surface anomalies) and geometric information (surface area and perimeter). A percent error of the compared surface area was found to range from 5%- 17%, and automatically acquired temperature measurements were within 7.8K of the recorded thermograph. The methods presented in this research showcase the beginning steps of integrated metrology in advanced manufacturing systems and automatic monitoring of per-part thermal behavior and part quality.