Papers by Author: D.L. Bourell

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Authors: B.Y. Stevinson, D.L. Bourell, J.J. Beaman
Abstract: Silicon infiltrated silicon carbide parts have been manufactured using selective laser sintering (SLS). The processing route has been defined, including post-processing steps: formation of a green part from silicon carbide powder using a phenolic binder, infiltration with a transient epoxy binder, dissociation of the binders thermally to create a brown part, heating the brown part to the infiltration temperature and infiltrating with molten silicon. A dimensional analysis study was performed. Cubes 25.4 mm on each side were selective laser sintered and measured after each processing step. The largest dilatation (volume strain), 7.3%, was associated with creation of the green part relative to the computer solid model. The smallest dilatation, -6%, was associated with binder dissociation shrinkage. These volume strains nominally offset, resulting in creation of nonmetallic parts with small dimensional errors relative to the computer solid model. This research was funded by the National Science Foundation under grant award DMI-0522176.
Authors: D.L. Bourell, R.S. Evans, S.L. Barrows
Abstract: There are several commercial processes for producing metallic parts by selective laser sintering (SLS) followed by infiltration of a molten metal at 700-900C. These parts are used in rapid manufacturing and rapid tooling applications. The present work centers around research to produce non-metallic parts infiltrated with materials at temperatures exceeding 1300C. Specific systems include siliconized silicon carbide. Of primary concern are: process control during the high-temperature infiltration; the binder system which must bind powder together during SLS, provide structural strength continuously from room temperature to the infiltration temperature, and react favorably with the infiltrant. This research was funded by State of Texas Technology Development and Transfer Grant Number 003658.
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