MICROSTRUCTURAL EFFECTS ON THE MACHINING PERFORMANCE OF DENTAL CERAMICS     D. T. Le, Lixun Qi and Guangming Zhang Department of Mechanical Engineering & the Institute for Systems Research University of Maryland College Park, Maryland 20742   Stanley J. Ng Naval Air Warfare Center Aircraft Division Department of the Navy Patuxent River, Maryland 20670     Abstract
   Constraints of mechanical, thermal, and chemical properties are making ceramics the material choice for industrial and dental applications. The quality of a machined surface of ceramics is fundamentally dependent on the response of the material to the machining process. This paper presents a combined analytical and experimental study with focus on optimizing the machining performance of dental ceramics -- DICOR/MGC -- with three distinguished microstructures. The study starts from analyzing the microstructural characteristics to searching for the machining conditions that provide satisfactory performance in terms of acceptable flexural strength. Evidence gained from the cutting force measurements and evaluation of fracture strength degradation indicates that the control of micro-scale fracture formed on the machined surface, with microstructural characteristics being considered, is the key factor which dominates the machining performance.