Doctoral Dissertations

Keywords and Phrases

infrared thermography; LPBF; Powder bed

Abstract

"Laser Powder Bed Fusion (LPBF) is a key technique in metal additive manufacturing and has undergone extensive research over the past few decades. It enables the fabrication of complex geometries directly from digital design models. The solidification process in LPBF is heavily influenced by the characteristics of the powder layer, including its thickness and thermal transport properties. Additionally, the performance of the printed part is impacted by the temperature history during solidification and the final residual stress field. While these topics have been the focus of many studies, almost all research has concentrated on ex-situ measurement and testing. These ex-situ techniques cannot replicate the printing chamber environment accurately to measure powder properties. Hence, they cannot provide real-time feedback to the LPBF system, nor do they aid in the real-time correction of printing parameters.

This dissertation aims to develop an in-situ measurement system to monitor the printing process and predict powder properties, temperature, and residual stress fields in real-time. An infrared camera is integrated into the LPBF machines to collect data on temperature and radiation signals. By combining this data with numerical, analytical, and AI models, the system can predict the powder thickness, thermal diffusivity, temperature, and residual stress fields in real time. This infrared thermography system adds significant insight to the LPBF process. Its low-cost and simple setup also make this approach attractive for industrial adoption" -- Abstract, p. iv

Advisor(s)

Leu, M. C. (Ming-Chuan)

Committee Member(s)

Kinzel, Edward C.
Huang, Jie
Yang, Xiaodong
Almasri, Mahmoud

Department(s)

Mechanical and Aerospace Engineering

Degree Name

Ph. D. in Mechanical Engineering

Publisher

Missouri University of Science and Technology

Publication Date

Summer 2024

Pagination

xviii, 214 pages

Note about bibliography

Includes_bibliographical_references_(pages 69, 119, 157, 174 & 201)

Rights

©2024 Tao Liu , All Rights Reserved

Document Type

Dissertation - Open Access

File Type

text

Language

English

Thesis Number

T 12395

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