| Summary: | 碩士 === 國立臺灣科技大學 === 機械工程系 === 96 === Sintered alumina parts large in dimension usually require intensive grinding before a final structure is attained. In order to enhance the yield rate of machining such large alumina parts, diamond tools having self-dressing behavior are required. The goal of this study was to improve the self-dressing behavior of metal-bond diamond tools by varying the composition of the bonding matrix. Metal-bond diamond tools using copper based alloys as the bonding matrices were used to grind sintered alumina using a CNC center-milling machine. Variation in the composition of the bonding matrix affects not only the mechanical properties of the bonding matrix but also the interfacial bonding strength between diamond grits and the bonding matrix, both of which determined the self-dressing behavior and tool life of the diamond tools as well as the yield rate of the alumina parts. The Compositions of the bonding matrix investigated in this study included Cu, Cu-15Sn, and Cu-15Sn-10Ti alloys. The behaviors and properties of the bonding matrix as well as the metal-bond diamond composite were determined by using, pin-on-disk abrasion test, Raman spectroscopy, X-ray diffraction, and scanning electron microscope. In addition, the grinding performances of the diamond tools which monitored by recording the frequency spectrum of vibration during grinding on alumina. The results based on frequency spectrum of vibration indicated that, by adding a small fraction of Ti to the bonding matrix, self-dressing behavior of the diamond tools could be improved. Such self-dressing behavior was found be strongly related to the formation of brittle matrix phases and enhanced bonding strength between the diamond grits and the bonding matrix with the addition of Ti into the bonding matrix. Along with improved self-dressing behavior, the grinding ratio of the diamond tools and the yield rate of the alumina parts were also enhanced.
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