Date on Master's Thesis/Doctoral Dissertation

1-2020

Document Type

Master's Thesis

Degree Name

M.S.

Department

Mechanical Engineering

Degree Program

Mechanical Engineering, MS

Committee Chair

Berfield, Thomas

Committee Co-Chair (if applicable)

Starr, Thomas

Committee Member

Yang, Li

Author's Keywords

additive manufacturing; surface roughness; exposure settings; stainless steel; dimensional accuracy; selective laser melting

Abstract

The relationship between varying contour settings and part geometry provides insight into the attainable surface roughness and dimensional accuracy of parts fabricated in 17-4 stainless steel via selective laser melting (SLM). Varying the contour settings of laser power (W), scan speed (mm/s), and beam offset (mm) for unsupported inclined bars. The utilization of a coordinate measuring machine (CMM) and surface profilometer quantified the dimensional accuracy and average surface roughness (Ra) for upface, downface, and topface surfaces. Adjusting the laser power and scan speed had minimal affect to surface roughness compared to part geometry. Part dimensionality was affected by the incline angle, laser power, and scan speed. Lower energy densities (J/mm) resulted in over-sized parts, while higher energy densities resulted in undersized dimensions. A clear relationship between varying contour settings and part geometry with the dimensionality and surface roughness of 17-4 fabricated benchmark parts was found.

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