Method for polishing ball screw and ball screw polishing apparatus

A ball screw polishing apparatus for polishing a ball screw comprising a screw shaft defining a screw axis, the screw shaft being formed with a screw groove having a lead and a lead angle, the ball screw polishing apparatus comprising:

• a holding mechanism configured to rotatably hold the screw shaft;
• a rotating mechanism configured to rotate the screw shaft at a rotational speed about the screw axis;
• a pressing roller configured to rotate about a rotational axis and having an outer peripheral surface;
• a tape-conveying mechanism configured to continuously or intermittently convey a polishing tape, the polishing tape having a polishing portion traveled around the outer peripheral surface;
• a tape-pressing mechanism configured to guide the polishing tape such that the polishing portion is traveled around the outer peripheral surface and press the polishing portion against the screw groove;
• a tilting mechanism configured to tilt the pressing roller such that the rotational axis is aligned with the lead angle;
• a linear oscillating mechanism configured to linearly oscillate the pressing roller along the rotational axis;
• a moving mechanism configured to move the polishing tape at a moving speed in a direction parallel to the screw axis;
• and
• a speed-synchronizing mechanism configured to synchronize the rotational speed with the moving speed based on the lead.