ABSTRACT
CONTENTS Summary ............................................................................................................. 110 Key Words .......................................................................................................... 110 5.1 Introduction ............................................................................................... 111 5.2 ELID Grinding Principle.......................................................................... 113
5.2.1 Electrodischarge Truing Technique........................................... 115 5.2.2 Electrical Behavior during Predressing .................................... 117 5.2.3 ELID Grinding Mechanism......................................................... 118
5.3 Experimental Setup .................................................................................. 118 5.3.1 Grinding Wheels........................................................................... 120 5.3.2 Grinding Fluid .............................................................................. 120 5.3.3 Power Supply ................................................................................ 121 5.3.4 Materials......................................................................................... 121 5.3.5 Measuring Instrument Used....................................................... 121
5.4 Results and Discussions .......................................................................... 122 5.4.1 Influence of Bond Material ......................................................... 122 5.4.2 Influence of Power Source .......................................................... 124 5.4.3 Comparison between Conventional and ELID Grinding ...... 125 5.4.4 Modified ELID Dressing Grinding ............................................ 127 5.4.5 Grinding with Bronze and Cobalt-Bonded Wheels................ 130 5.4.6 Investigation of Grinding Ratio ................................................. 130 5.4.7 Efficient Cylindrical Grinding on a Turning Center .............. 134 5.4.8 Ultraprecision Grinding with ELID........................................... 135
5.4.8.1 SEM and AFM Studies ................................................. 138 5.4.9 Flexural Strength of Silicon Nitride .......................................... 139
5.5 Conclusions................................................................................................ 142 5.6 Acknowledgments .................................................................................... 143 References ........................................................................................................... 143
SUMMARY In manufacturing parts from structural ceramics, grinding costs can constitute up to 80% of the total manufacturing costs; this has been well documented. The high cost of manufacturing is attributed to: (a) the low material removal rates (MRR) and (b) the high wear of the superabrasive wheels. By maximizing the MMR, grinding costs can be reduced significantly. However, high MRR leads to increased wear of the grinding wheel, which requires frequently redressing the grinding wheel by stopping the process. One of the authors of this paper, Dr. Ohmori, has pioneered a novel grinding technology, known as electrolytic in-process dressing (ELID), which incorporates ‘‘in-process dressing’’ of metal-bonded grinding wheels. This technology provides dressing of the metal-bonded wheels during the grinding process, while maintaining continuous protrudent abrasive from the superabrasive wheels. With ELID grinding applied to various structural ceramic materials for high MRR, successful grinding operations were accomplished using coarse grit-sized wheels. ELID grinding provided stable operations and achieved high MRR in conventional grinding machines. Both the principle and the characteristics of ELID grinding, with emphasis on their importance in industrial applications in the manufacture of ceramic components, will be addressed in this paper.
