Selective Laser Sintering of Low Density, Low Coefficient of Thermal Expansion Silica Parts

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Date

2016

Authors

Hostetler, John M.
Goldstein, Jonathan T.
Urbas, Augustine M.
Gutierrez, Rodrigo E.
Bender, Theresa E.
Wojnar, Charles S.
Kinzel, Edward C.

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University of Texas at Austin

Abstract

This paper presents a study of selective laser sintering of silica-gel. The objective of this work is to investigate a technique to create free-form, low to zero coefficient of thermal expansion structures. This offers potential cost savings over the conventional casting of large pieces of glass-ceramic followed by machining lightening features. In this paper, A CO2 laser is coupled through a gantry system and focused onto a binder-free silica-gel powder bed (15-40 µm particles). Prior to writing each layer, powder is dispensed by sifting it onto the build platform as opposed to a conventional wiper system. This avoids contacting and potentially damaging sensitive parts. After deposition, the parts are annealed in a furnace to increase their strength. The influence of various process parameters including scan speed and laser power on final shape is investigated. In addition, the flexural strength of annealed parts is measured via three-point bending tests.

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