Patent ID: 7794306
Filing Date: 2010-09-14
Classification: B24B

Abstract:
1. A surface finishing apparatus for surface finishing a target shaped periphery of a workpiece into a mid-concave profile, comprising: a workpiece supporting mechanism for supporting the workpiece having the target shaped periphery to be surface finished; a surface finish tool including a lapping film adapted to be in abutting contact with the target shaped periphery of the workpiece; a pressure applying mechanism including a plurality of shoes disposed on a rear side of the lapping film to be operative to apply a pressure force to the lapping film to cause the lapping film to be held in pressured contact with the target shaped periphery of the workpiece; a drive mechanism for rotating the workpiece about an axial direction during operation of the pressure applying mechanism to allow the surface finish tool to surface finish the target shaped periphery of the workpiece into the mid-concave profile, while exhibiting a distribution pattern of the pressure force of the surface finish tool; and an oscillating mechanism for oscillating at least one of the workpiece and the lapping film in the axial direction of the workpiece in a given oscillation stroke such that a working position of the lapping film is cyclically shifted in the given oscillation stroke with respect to the target shaped periphery of the workpiece to allow the workpiece to be surface finished in the mid-concave profile, wherein the pressure applying mechanism is adapted to operatively hold the plurality of shoes on the rear side of the lapping film in different contact areas in a partially overlapping relationship at a central region of the target shaped periphery of the workpiece and in non-overlapping relationship in both terminal regions of the target shaped periphery such that the plurality of shoes are held in opposing offset positions with offset displacement of each of the plurality of shoes set to be less than the given oscillation stroke provided by the oscillating mechanism to allow the central region of the target shaped periphery to be lapped at a greater rate than those at which other regions of the target shaped periphery are lapped, resulting in the target shaped periphery having a surface profile formed in the mid-concave profile having a depth equal to or greater than 5 μm and equal to or less than 20 μm.