1/9/2014 Julia Cation
Written by Julia Cation
Chandra Nath, a postdoctoral research associate in MechSE, has placed himself in excellent company—alongside professors from top-tier universities and experienced engineers from large companies around the world—upon winning the prestigious SME 2014 Outstanding Young Manufacturing Engineer Award. Nath is one of six recipients of the award, which recognizes manufacturing engineers, age 35 or younger, who have made exceptional contributions and accomplishments in the manufacturing industry.
The honor from SME (the Society of Manufacturing Engineers) was based on Nath’s leadership, achievements, and research in manufacturing engineering. His research comprises modeling, simulation, and experimental works that led to the scientific understanding and development of advanced manufacturing processes and systems in the field of multi-scale machining of difficult-to-cut materials, including hardened/alloy steels, titanium- and nickel-based alloys, tungsten carbide, structural ceramics, and nanocomposites.
Nath has been working on multiple projects with Professor and Grayce Wicall Gauthier Chair Shiv G. Kapoor since 2011. One of these projects is the development of a new atomization-based cutting fluid (ACF) spray system for effectively machining difficult-to-cut materials—mostly aerospace materials like titanium and nickel alloys, which produce extremely high temperatures (nearly 2,000o F) during machining, ultimately decreasing the life of the cutting tool.
Traditional flood cooling methods utilize an excess of cutting fluid to ensure coverage. “Generally, the cutting tool-chip interface is small, say, within a few square millimeters, but the cutting fluid covers a much larger area surrounding the interface, which means there is a ton of excess cutting fluid with no effective use to improve tool life. Currently, commercial industries in North America use about two billion gallons of cutting fluid every year,” said Nath.
The high pressure coolant—another method to penetrate the cutting fluid at the cutting interface—is not good for the health and safety of the operator and others on the shop floor. Additionally, said Nath, “High pressure means the delivery of more cutting fluid. It requires a lot of setup, which means you’re using a lot of energy. Overall productivity is not improved that much, either. And you cannot dispose of coolant just anywhere. The U.S. government charges companies a fee to dispose of the chemical coolant because it’s hazardous to the environment.”
Nath’s ACF spray system overcomes these challenges. It consists of a standard ultrasonic atomizer, small fluid tank, high-velocity gas delivery system, and a simple nozzle unit. It uses a fast-moving thin layer of cutting fluid from the atomized droplets, which penetrates into the tool-chip interface to reduce the cutting temperature and friction coefficient in a much more targeted and effective way. Generally, commercial cutting uses about four liters of cutting fluid per minute. By comparison, Nath’s new spray system uses 10-20 mL.
Impressively, with his new system, Nath found a 30-50% improvement in tool life over conventional cooling during the machining of a titanium-based alloy.
Since the small amount of fluid is gravity-fed during machining, the spray system requires no pump. And as the amount of fluid delivery is so small, it also doesn’t require an expensive fluid filter unit in the setup. Additionally, the spray system is designed to use compressed CO2 from a cylinder that happens to be a by-product from the food processing industry.
Nath’s cooling fluid is not chemically different than that used in conventional cooling methods. It simply uses a smaller amount of cutting fluid more effectively. It is in the application of it that Nath’s work is unique.
“Because of all these advantages, the system not only improves tool life, but also productivity, and becomes highly energy efficient and environmentally friendly,” said Nath. Not surprisingly, Nath’s ACF spray system has attracted significant funding from both industry sources and the National Science Foundation (NSF). Additionally, a research paper entitled, “Characterization of Fluid Film Produced by an Atomization-Based Cutting Fluid (ACF) Spray System During Machining,” co-authored with Kapoor and Alexander C. Hoyne (MSME 2013), won a third-place ASME Best Paper Award at the Manufacturing Science and Engineering Conference in June 2013.
TechSolve Inc., an Ohio-based aerospace manufacturing company that first supported the project for machining aerospace alloys, has implemented a prototype of the system in their technology development center, and has been conducting additional experiments with the goal of commercializing the ACF cooling technology within the manufacturing sector. The University of Illinois has filed for a provisional patent and an invention disclosure on the spray system technology.
Nath is helping lead the way in advanced multi-scale manufacturing. He is involved in several research collaborations with professors at the University of California at Los Angeles and Renessaler Polytechnic Institute in New York. He collaborated with professors at the National University of Singapore during his work as a research scientist at the Singapore Institute of Manufacturing Technology, a national research lab in Singapore. Nath has supervised several students in their research projects, has been published in 35 journal and conference publications, and has given talks around the world.
Nath is also a visiting lecturer at Illinois for two mechanical engineering courses at the undergraduate and graduate levels.