SURFACE INTEGRITY OF WIRE ELECTRO-DISCHARGE MACHINED AL_(2)O_(3) CERAMIC COMPOSITE

摘要

More and more applications need ceramic composites with high quality surface. Surface integrity plays an extremely important role in the unexpected fracture and the reliability in service. The machining of ceramic composites proves to be a sticky problem because it is almost inevitable that some micro-structural flaws, especially microcracks, remain in the machined surface. Cracks, micro-cracks and hidden micro-cracks in the surface are detrimental to the reliability of the ceramic composite parts. On the basis of the present knowledge, the principal limiting factor for Electro-discharge machining (EDM) is the electrical conductivity of workpiece material with a threshold value of either 100Ω·cm or 300Ω·cm. Apart from the generation of extremely complex geometry through ED sinking and wire cutting, electro-discharge processing can be performed regardless of the hardness and strength of workpiece materials, and the machining forces exerted on the workpiece materials are negligible. These specific advantages provide opportunities to the design engineer.