Abstract: Hard and brittle materials, such as optical glass, engineering ceramics, and silicon-based materials, are widely used in high-tech fields, such as optical engineering and integrated circuits, because of their good physical and chemical properties. Their low plasticity and high brittleness lead to low efficiency and poor surface quality during cutting. A model of wire saw velocity and normal cutting force in the cutting process of diamond wire saw is established, and a minimum variance self-tuning controller is designed for controlling the cutting force on-line in real-time. The experimental results show that the minimum variance self-tuning controller can be used to reduce the fluctuation of cutting force on the slice in the wire saw cutting system, and make the cutting force tend to be stable. Compared with the slice cutted under the condition of the constant parameters, the surface of work-piece finished using the minimum variance self-tuning control strategy is relatively smooth, and the surface roughness is decreased by about 30%. Key

Key words: brittlematerial, wiresawcutting, wiresawvelocity, normalforce, minimumvarianceself-tuningcontrol, surfaceroughness