Multistage fine hole machining method and device

A multistage fine-hole machining device comprising:

• a plurality of lap stations each for lapping an inner surface defining a through-hole of a workpiece to enlarge a diameter of the through-hole, each of the lap stations having a holding unit for holding the workpiece, a wire supply unit for supplying a wire, a passing unit for passing the wire supplied from the wire supply unit through the through-hole of the workpiece, a tension applying unit for applying tension to the wire passed through the through-hole of the workpiece by the wire passing unit, a polishing material supply unit for supplying a polishing material to the wire, and a sliding unit for effecting relative sliding movement between the workpiece and the wire during a lapping operation while the workpiece is held by the holding unit, the wire is passed through the through-hole of the workpiece by the passing unit, tension is applied to the wire by the tension applying unit, and the wire is supplied with the polishing material by the polishing supply unit to thereby lap the inner surface of the workpiece with the polishing material and enlarge the diameter of the through-hole;
• whereby the through-hole of the workpiece is successively enlarged during lapping operations.

A multistage fine-hole machining device comprising:

• a plurality of lap stations each having a holding unit for holding a workpiece having an inner surface defining a through-hole, a first supply unit for supplying a wire, a passing unit for passing the wire supplied from the first supply unit through the through-hole of the workpiece, a second supply unit for supplying a polishing material to the wire, and a sliding unit for effecting relative sliding movement between the workpiece and the wire during a lapping operation while the workpiece is held by the holding unit, the wire is passed through the through-hole of the workpiece by the passing unit, and the wire is supplied with the polishing material by the second supply unit to thereby lap the inner surface of the workpiece with the polishing material and enlarge the diameter of the through-hole;
• and
• a transfer device for successively transferring the workpiece to each of the lap stations to lap the inner surface of the workpiece at each of the lap stations during the lapping operation for successively enlarging the diameter of the through-hole to a preselected diameter.