Masters Theses

Abstract

"The purpose of this research is to develop a process that will enable a Selective Laser Sintering (SLS) machine to create geometrically complex green parts of various sizes that become strong, dense ceramic parts after sintering. This will be applicable to SLS systems already operational in industry, and may offer a more cost-effective, more time-efficient method for producing high-temperature ceramic rapid prototype parts. Alumina was the chosen ceramic for the developmental stage of this research. Fine alumina powder (average particle size of 0.4 µm) was coated with stearic acid, which served as a binder. Green parts were made from this powder using low temperature, low laser power SLS processes. The green strength of parts produced in this research was sufficient for safe transport and to survive the binder burnout process to remove the organic binder. The average final density of fully sintered parts was 88% of the theoretical density for alumina (3.96 g/cm³), and the average flexural strength of fully sintered flexural test bars was 255 MPa. The sintered parts have an average surface roughness of approximately 7.6 µm without any finishing processes such as grinding or polishing. No infiltration, compaction, or post-processing other than binder burnout/sintering is required to achieve these results. Holes of diameters less than 1 mm and holes with multiple bends have consistently been produced in Al₂O₃ parts of various thickness and height. Average dimensional variances are approximately 0.12 mm for hole diameters and 0.25x0.27x0.21 mm for the length, width, and height of flexural strength bars, respectively. Features of green parts produced in this research include sharp corners, crisp lines, flat surfaces, complex holes, slots, and overhangs"--Abstract, page iii.

Advisor(s)

Leu, M. C. (Ming-Chuan)

Committee Member(s)

Hilmas, Greg
Liou, Frank W.

Department(s)

Mechanical and Aerospace Engineering

Degree Name

M.S. in Mechanical Engineering

Sponsor(s)

Air Force Research Laboratory (Wright-Patterson Air Force Base, Ohio)

Publisher

University of Missouri--Rolla

Publication Date

2007

Pagination

x, 114 pages

Note about bibliography

Includes bibliographical references (pages 37-40).

Rights

© 2007 Jason John Nolte, All rights reserved.

Document Type

Thesis - Open Access

File Type

text

Language

English

Library of Congress Subject Headings

Sintering
Solid freeform fabrication
Aluminum oxide -- Testing
Rapid prototyping

Thesis Number

T 9173

Print OCLC #

861190857

Electronic OCLC #

861223197

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