Doctoral Dissertations

Cody S. Lough

Keywords and Phrases

Additive Manufacturing; In-Situ Monitoring; Laser Powder Bed Fusion; Thermography

Abstract

“Laser Powder Bed Fusion (LPBF) metal Additive Manufacturing (AM) fabricates 3D metal parts layer-by-layer. The process enables production of geometrically complex parts that are difficult to inspect with traditional methods. The LPBF parts experience significant geometry driven thermal variations during manufacturing. This creates microstructure and mechanical property inhomogeneities and can stochastically cause defects. Mission critical applications require part qualification by measuring the defects non-destructively. The layer-to-layer nature of LPBF permits non-intrusive measurement of radiometric signals for a part’s entire volume. These measurements provide thermal features that correlate with the local part health. This research establishes Optical Emission Spectroscopy (OES) and Short-Wave Infrared (SWIR) imaging radiometric inspection methods that infer the final material state in LPBF. The instruments’ signals are correlated with bulk and local part properties to evaluate prediction capabilities. A probability framework defines the SWIR camera’s local defect detection successes and limitations. Finally, a superposition thermal model based on SWIR data predicts laser scan path driven thermal history effects for process correction applications”--Abstract, page iv.

Advisor(s)

Drallmeier, J. A.

Committee Member(s)

Kinzel, Edward C.
Landers, Robert G.
Bristow, Douglas A.
Newkirk, Joseph William

Department(s)

Mechanical and Aerospace Engineering

Degree Name

Ph. D. in Mechanical Engineering

Comments

This work was funded by Honeywell Federal Manufacturing & Technologies under Contract No. DE-NA0002839 with the U.S. Department of Energy.

Publisher

Missouri University of Science and Technology

Publication Date

Spring 2021

Journal article titles appearing in thesis/dissertation

  • In-Situ Optical Emission Spectroscopy of Selective Laser Melting
  • Correlation of SWIR Imaging with LPBF 304L Stainless Steel Part Properties
  • Local Prediction of Laser Powder Bed Fusion Porosity by Short-Wave Infrared Imaging
  • Rapid Thermal History Prediction for Laser Powder Bed Fusion by Experimentally Informed Superposition Model

Pagination

xiii, 117 pages

Note about bibliography

Includes bibliographic references.

Rights

© 2021 Cody Shannon Lough, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Thesis Number

T 12070

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Included in

Manufacturing Commons

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