Professor’s grinding research provides efficient solution

HOBOKEN, N.J. — Sharpening the saw – or in this case the grinding wheel – used to mean you had to slow down or stop working. Not anymore, thanks to some award-winning research at Stevens Institute of Technology.

For decades, researchers have sought efficient and cost-effective methods for machining materials. Because of its high precision and high productivity, grinding has been the dominant process for machining various metals, alloys, ceramics, metal-ceramic composites and semiconductor materials.

However, the process becomes time consuming and costly because of constant wear and tear on the grinding wheel, and it is necessary to sharpen the grinding wheel consistently.

Dr. Zhenqi Zhu, assistant professor in the Department of Mechanical Engineering at Stevens Institute of Technology, has been researching the sharpening process, known as dressing. His research supports in-process dressing of grinding wheels during high-speed grinding as a cost-effective and efficient solution to this problem.

According to Zhu, mechanical dressing can be carried out in two ways. One way is to sharpen the grinding wheel using a diamond or other abrasive tool while the grinding wheel is grinding a part. This is known as in-process dressing. The other way is to stop the grinding process and sharpen the wheel manually.

Both methods require hard-to-find, experienced operators who decide process parameters, and both methods have to be performed at low speeds. Zhu says this makes the sharpening process costly and time consuming.

In addition to the mechanical dressing methods, various chemical or thermal methods have been used in the industry. The best of these methods for precision grinding is called electrolytic in-process dressing (ELID), which was invented in Japan about 10 years ago. This process is capable of dressing super-abrasive wheels consistently. Worn abrasives are removed and new abrasives are exposed as the bond material holding the abrasives together is etched away gradually. The wheel wear rate and its corresponding etching rate are kept the same, autonomously determined by the principle of electrolysis.

According to Zhu, the major weakness of ELID is that it is only effective at low grinding speeds, which is expensive and reduces productivity. More importantly, he says the speed is too low for most industrial applications.

In answer to these challenges, Zhu has conducted research on high-speed ELID, known as HELID. The HELID process, proposed at Stevens with patent pending, is a method of dressing grinding wheels running at high speeds with consistency and efficiency. This in-process dressing method keeps wheel consumption and machine time to a minimum. It also sharpens high-speed grinding wheels for precision or ultra-precision grinding.

Zhu’s research, Innovative Approach of Electrolytic In-Process Dressing for High-Speed Grinding, recently received recognition for best paper at the Third International Machining and Grinding Conference. In his research, Zhu and his research assistant, Xiaoming Liu, propose to use traveling foil electrodes to establish an electrolyte film between the electrode and the grinding wheel surface, thus allowing high-speed grinding without breaking down the electrolyte film essential to the electrolytic in-process dressing.

For more information, reporters may contact Zhu at (201) 216-5582 or via e-mail at zzhu2@stevens.edu.

About Stevens Institute of Technology

Founded in 1870, Stevens Institute of Technology is one of the leading technological universities in the world dedicated to learning and research. Through its broad-based curricula, nurturing of creative inventiveness, and cross disciplinary research, the Institute is at the forefront of global challenges in engineering, science, and technology management. Partnerships and collaboration between, and among, business, industry, government and other universities contribute to the enriched environment of the Institute. A new model for technology commercialization in academe, known as Technogenesis®, involves external partners in launching business enterprises to create broad opportunities and shared value.

Stevens offers baccalaureates, master’s and doctoral degrees in engineering, science, computer science and management, in addition to a baccalaureate degree in the humanities and liberal arts, and in business and technology. The university has a total enrollment of 2,150 undergraduate and 3,500 graduate students, with about 250 full-time faculty. Stevens’ graduate programs have attracted international participation from China, India, Southeast Asia, Europe and Latin America. Additional information may be obtained from its web page at www.stevens.edu.  

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