A Missouri University of Science and Technology proposal to produce 3-D tooling components more quickly and cost-effectively was one of seven selected for development by the National Additive Manufacturing Innovation Institute (NAMII), a program administered by the National Center for Defense Manufacturing and Machining.

Missouri S&T and Northrop Grumman Aerospace Systems will co-lead projects that will focus on fused deposition modeling (FDM®), a commercially successful process of additive manufacturing and rapid prototyping. The Robert C. Byrd Institute’s Composite Center of Excellence, Stratasys Inc. and The Boeing Co. are also involved in the projects.

Additive manufacturing uses a digital model to construct objects in layers. The method can create complex 3-D shapes and produces far less scrap than conventional methods.

“Our project will investigate the use of ‘sparse-build’ versus ‘solid-build’ molds and dies,” says Dr. Ming Leu, the Keith and Pat Bailey Missouri Distinguished Professor of Integrated Product Manufacturing at Missouri S&T. “Solid-build has zero porosity, but sparse-build has various levels of engineered porosity. Leu is collaborating with Dr. K. Chandrashekhara, Curators’ Professor of mechanical and aerospace engineering at Missouri S&T.

“The purpose of sparse-build is to save material, thus saving fabrication cost and time,” he says. “But the parts are not as strong, thus research is needed about how to optimize sparse-build in order to save cost and time while satisfying the requirement on part properties.”

Samples constructed by a Stratasys’ Fortus machine using ULTEM 9085, a flame-retardant, high-performance thermoplastic material, will go through a series of compression and flexure tests at both room and elevated temperatures.

“We will compare different kinds of sparse-builds in detail in terms of material need, mechanical properties, etc., and will study whether they are strong enough for multiple runs in vacuum-assisted resin transfer molding and hydroforming applications,” says Leu.

“NAMII’s fundamental objective is to spawn the creation of new, innovative products and the corresponding U.S. jobs to support them based on the unique capabilities of additive manufacturing,” said NCDMM Vice President and NAMII Director Ed Morris in a statement. NAMII will provide $4.5 million in funding toward the seven projects.