GRINDING MACHINE

PURPOSE: A grinding machine is provided to buffer vibration and to enhance processing precision with air cushion formed by pneumatic pressure in a tool holder. CONSTITUTION: A grinding machine consists of a pneumatic pressure generator(2) generating pressure using air; a tool holder(4) communicated with a pneumatic suction device(8) and installed on a main rotating shaft ; a position sensor(14) detecting the position of a grinding stone(6) in the tool holder; a controller(22) controlling pneumatic amount from the pneumatic suction device to a space unit(4a) by controlling the grinding stone, the pneumatic pressure generator according to the position of the grinding stone. The tool holder includes a fixing shaft(10) for the pneumatic suction device and the space unit for the grinding stone. The size of the space unit is different according to air pressure through the pneumatic suction device. Further, the tool holder includes an air discharge hole(12) to form the movement of pneumatic pressure. A guide rail is vertically installed to guide the grinding stone and a porous rubber material is installed in the space unit to support the grinding stone. Thus, vibration is attenuated with air cushion and processing precision is enhanced with the guide rail.