
Dr. Dave Bourell (left), a professor of mechanical engineering at The University of Texas at Austin, receiving the International Solid Freeform Fabrication Symposium Freeform and Additive Manufacturing Excellence (FAME) Award for his work in additive manufacturing. In this photo, he is presented with a $2,000 check from Dr. Rich Crawford, also from the Mechanical Engineering Department at The University of Texas at Austin.
Dr. David L. Bourell has been honored with the International Freeform and Additive Manufacturing Excellence (FAME) Award, sponsored by the Solid Freeform Fabrication Symposium under the aegis of the Advanced Manufacturing Center of The University of Texas at Austin. The award was granted for Dr. Bourell's pioneering work in the development of a manufacturing process known as Laser Sintering (LS), for which he holds 14 patents and has published over 200 publications including journal articles and conference proceedings since 1990. Laser sintering is a rapid manufacturing process in which objects are constructed by fusing together small particles of plastic, metal, ceramic, or glass.
Professor Dave Bourell

Professor David Bourell photographed in his office at The University of Texas at Austin, March 9, 2011.
Dr. Bourell is a Professor of Mechanical Engineering (ME) and Materials Science and Engineering at The University of Texas at Austin and serves as director of the Laboratory for Freeform Fabrication. Having worked in the area of Laser Sintering since 1988, Professor Bourell is a leading expert in the field and was the lead author on the original materials patent for LS technology. Issuing in 1990, this patent has been cited in over 100 other patents and represents the original intelletual property for mixed and coated powders for LS, including binders, used to build objects in this additive manufacturing process, also known as a type of three-dimensional printing.
Professor Bourell has previously received several other awards for his work on LS, as well as his career as a teacher. He was the 2009 recipient of the Outstanding Scientist/Engineer Award from the Materials Processing and Manufacturing Division (MPMD) of The Minerals, Metals and Materials Society (TMS) He received the Japan Society for the Promotion of Science Fellowship in 2006. He was the 1998 recipient of the Cockrell School of Engineering's Lockheed Martin Award for Excellence in Engineering Teaching. He was elected Fellow of ASM International (Materials Information Society) in 1997 and Fellow of TMS in 2011. In 1991, he was the recipient of a prestigious Alexander von Humboldt Research Fellowship to the Max Planck Institute Powder Metallurgy Research Lab in Stuttgart, Germany, now known as the Max Planck Institute for Intelligent Systems. He won the ASM International Bradley Stoughton Award for Outstanding Young Teachers of Metallurgy in 1986. He is internationally recognized in the field of Additive Manufacturing (AM) and is chair of the Organizing Committee of the annual Solid Freeform Fabrication (SFF) Symposium, the leading research conference in the world on this subject.

Newly manufactured UT Tower models still standing in some excess plastic powder.
Laser Sintering
Laser sintering is a type of 3D printing technique used in additive manufacturing. Additive manufacturing is a relatively new method of manufacturing in which objects are constructed by joining materials together and has many advantages over traditional subtractive manufacturing) methods in which unwanted material is cut away from stock material like wooden blocks, metal bars, etc. in order to form the desired object. By removing the constraints of conventional manufacturing methods such as tool clearance (the need for cutting tools to be able to reach the desired material to be cut), additive manufacturing methods such as LS are able to create complex components that would otherwise be impossible to manufacture without breaking them down into smaller parts. Several examples are shown in this video featuring Dave Bourell at Austin's annual South by Southwest festival.
The process of LS begins with a thin layer of loose plastic powder laid flat across the building surface. Next, a computer-controlled high-power CO2 laser fuses (sinters) the plastic powder together into one layer of the desired shape of the part being constructed. The part is then lowered into a cylinder (shown on the right side of the diagram) while a vat of more plastic powder (shown on the left side of the diagram) is simultaneously raised up onto the building surface.

A diagram depicting the process of Selective Laser Sintering.
A roller mechanism pushes the new supply of plastic powder flat across over the previously sintered layer, and then the new layer of powder is sintered onto the top of the existing part. The process repeats, adding one thin layer at a time until the entire part has been fabricated. By building one solid object from the ground up, LS can construct just about any three-dimensional object or enclosed combinations of physical objects, such as one solid box inside of another without any openings to get the smaller box in or out. A more complex example of such an object is the Archimedes Screw designed by Mechanical Engineering alumna Kelly Alexander, which is built entirely of solid plastic - no screws, glue, or other adhesive tools.