The American Society of Mechanical Engineers recently recognized four Missouri University of Science and Technology researchers for their paper describing an additive manufacturing method for fabricating 3-D parts by extrusion of water-based ceramic pastes.

Drs. Ming Leu (second from left) and Robert G. Landers (third from left) receive the ASME award from (at left) award committee chair Dr. Shreyes Melkote and (at right) Dr. Brad Kinsey, ASME manufacturing engineering division chair.

Mingyang Li, a current Ph.D. student, and Lie Tang, a recently graduated Ph.D. student, both in mechanical engineering at Missouri S&T, and their faculty advisors, Dr. Robert G. Landers and Dr. Ming Leu, received the 2014 ASME Blackall Machine Tool and Gage Award for a two-part paper describing the research. The four received the award on June 11 during the 2014 ASME International Manufacturing Science and Engineering Conference in Detroit, Michigan.

The award is presented annually for the most outstanding paper published in the ASME’s Journal of Manufacturing Science and Engineering during the preceding two years. The Missouri S&T researchers’ two-part paper describes a mathematical model for fabricating ceramic parts known as “freeze-form extrusion fabrication,” as well as experimental verification of the model.

The process involves mixing ceramic materials with water to create a paste that is then extruded to form manufactured parts. This approach is an additive manufacturing method, which is known broadly as “3-D printing,” because it creates parts layer by layer.

Unlike other additive manufacturing techniques, however, freeze-form extrusion fabrication occurs in a low-temperature environment, which causes the water in the ceramic paste to freeze and the part to maintain its shape during the fabrication process. In their two-part paper, the researchers discuss the impact air bubbles in the mixture, as well as extrusion force, have on the paste extrusion velocity. They conclude that settling time decreases rapidly as the extrusion force – the force at which the paste is pushed out of extruder nozzles – increases. When the extrusion force increases beyond a certain value, however, the settling time changes slowly. They also found that when more air is trapped in the material, it takes longer for the extrusion force to settle.

Ceramic materials are widely used in the automotive and aerospace industries because of their hardness and heat-resistance capabilities, the researchers write in their paper, “Extrusion Process Modeling for Aqueous-Based Ceramic Pastes – Part 1: Constitutive Model and Part 2: Experimental Verification.” Both parts of the paper were published in the October 2013 issue of ASME’s Journal of Manufacturing Science and Engineering (part 1) (part 2).

Landers is a professor of mechanical engineering and associate chair for graduate affairs. Leu is the Keith and Pat Bailey Missouri Distinguished Professor of Integrated Product Manufacturing. He also leads the Advanced Manufacturing signature area, one of four leading research efforts at Missouri S&T that were announced earlier this year.