Mechanical Engineering ETDs

Publication Date

Spring 4-10-2019

Abstract

Laser powder bed fusion additive manufacturing consists of a process that incorporates many process variables into fabricating parts. This study investigated several of these process variables and determined their influence on part properties. The process variables investigated include laser power, velocity, focus offsets, layer thickness, and powder particle size. Physical properties will be compared including surface roughness, form, and density. Tensile testing provided mechanical properties including unloading Young’s modulus, ultimate tensile strength, yield strength, uniform elongation, and ductility. Process maps will be developed that will provide recommendations for these process settings. It will be shown that these laser settings can be used to maximize physical properties and manipulate the mechanical properties. Several samples had their grains analyzed showing that laser settings also have an influence on grain sizes. Two simple models were tested for accuracy against experimental results. The results from the models showed they can be used as a starting point for future process optimization studies.

Keywords

Additive Manufacturing, Process Development, Laser Powder Bed Fusion, Laser Characterization, Mechanical Property Minipulation

Degree Name

Mechanical Engineering

Level of Degree

Masters

Department Name

Mechanical Engineering

First Committee Member (Chair)

Dr Yu-Lin Shen

Second Committee Member

Dr Mehran Tehrani

Third Committee Member

Dr Bradley Jared

Document Type

Thesis

Language

English

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