| Summary: | 碩士 === 國立清華大學 === 動力機械工程學系 === 104 === Sapphire (single-crystal Al2O3) is highly used in LED, semiconductor, optical and communication industries, because of its high hardness, great optical transparency and chemical stability. In engineering applications, sapphire is always required to be thinning and high surface integrity. However, sapphire is very difficult to grind because of extraordinarily hard material property with Vickers hardness 2200 Kg/mm2.Two-dimension ultrasonic assisted grinding (2D-UAG) has been proved to be promising in machining of hard and brittle materials. However, its potential has not been sufficiently developed because the processing mechanism has not been clearly explained.
In this paper, the trajectory of abrasive in different amplitude of 2D-UAG are analyzed. It gives the relationship of amplitude and equivalent chip thickness. The grinding experiments under the existence/non-existence of 2D-UAG are performed. The grinding process transform from brittle to ductile mode. It’s estimated by experiments to verify that the grinding force, specific grinding energy, surface formation mechanism and chip formation of 2D-UAG.
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