Rolla Researchers Examine 3D “Hybrid” Manufacturing

The Missouri University of Science and Technology in Rolla has been a studying and developing metalcasting processes over many decades, and just like industrial metalcasting Missouri S&T is making advances into the arena of “additive manufacturing” – the still not-fully-defined landscape of computer-aided design, material science, laser technology, prototyping, and 3-D printing that is causing manufacturers everywhere to rethink their production process priorities.

With some financial support from NASA, researchers at Missouri S&T’s Laser Aided Manufacturing Process (LAMP) Laboratory are running computer simulations of processes that could be used to produce stronger, more durable materials to be used in aerospace design. According to Dr. Frank Liou, director of the LAMP center and the Michael and Joyce Bytnar Professor of Product Innovation and Creativity, the project may also involve fabricating some of those new materials.

Dr. Liou and his colleagues have been developing additive manufacturing techniques for more than a decade, specifically working with the direct metal laser sintering method of converting CAD designs into metal parts.  The process involves using high-powered lasers to melt particles of powdered materials as they exit a nozzle, creating three-dimensional shapes. The technique is similar to 3-D printing, which is the term that describes other techniques in which CAD data is used to define a shape that is built by different technologies (stereo lithography, for example.)

Laser sintering is the same process that researchers at Case Western Reserve University are using to develop die design and repair techniques, a project that earned support from the National Additive Manufacturing Innovation Institute.

Liou pointed out that additive technologies can be applied in numerous ways across a range of manufacturing sectors, to produce large-scale designs like aerospace parts to minuscule structures in bioengineered materials for use as surgical implants. For some applications, additive manufacturing can produce a denser, stronger material than conventional methods (e.g., milling, machining or forging.) Liou, who also directs Missouri S&T’s manufacturing engineering program, said the steel parts the have produced using laser sintering are 10% stronger than a comparable structure would be if it had been machined from a steel workpiece.

In the research study, Liou is combining additive manufacturing with more conventional approaches to creating materials. He calls the approach “hybrid manufacturing.” The Missouri S&T researchers are taking the additive manufacturing route to produce aerospace components from two different metals – e.g., steel and copper – and then finishing the parts using CNC machining.

Liou received an estimated $660,000 from NASA to develop computer models of various additive-manufacturing approaches, which he indicated would be used to study how layered materials adhere to different surfaces on which they are deposited. “In many aerospace or biomedical applications, you cannot afford metal fatigue,” he said. “It is important to understand how well a deposited metal bonds to the surface.”

Also, NASA recently awarded $750,000 more to Liou, to support the next step of this research: fabricating new or rare materials not generally found in nature. This research could lead to stronger metals as well as to ways for repairing parts or structures.