| 摘要 |
PURPOSE:To facilitate centering by providing a workpiece cradle into which numerous pores, jetting compressed air toward the surface where the workpiece is placed, have been substantially vertically bored and by floating the workpiece by supplying jetting air onto the cradle. CONSTITUTION:When processing a workpiece 3 in the first time, valves 71, 71' and 72'' are selected and opened in such a way that compressed air is jetted from a pore 41 corresponding to the base area of the workpiece 3. Then, a valve 72 is opened while adjusting it according to the weight of the workpiece 3 in such a way that the workpiece 3 is slightly floated on a cradle 4. For the second workpiece and the subsequent, the floating is effected by only handling the valve 72. Next, a hole is drilled by means of a drill 2 after manually bringing the outer periphery of the workpiece 3 to come in contact with a ring 6 and permitting a prepared hole 31 to come just under the drill 2. Since the workpiece is subjected to floating, centering can be automatically performed with improved efficiency, allowing a cutter to take a new lease on life. |
