A control device includes a control part which generates a torque command based on a resultant command, which is obtained by adding a position deviation, which is the difference between a position command and the actual position of a feed shaft, to an oscillation command to control the feed shaft, and an elastic deformation amount calculation part which calculates the elastic deformation amount of a structure composed of a tool or workpiece and the feeding mechanism therefor based on the torque command. An oscillation command generation part generates the above oscillation command based on the rotation speed of the workpiece, the position command of the feed shaft, and the above elastic deformation amount.

A lathe includes a spindle rotatable on a spindle axis, a tool post to which a tool is attachable, an X1-axis ball screw extended in an X1-axis direction perpendicular to the spindle axis and capable of moving the tool post in the X1-axis direction, and an X1-axis support bearing provided on an end of the X1-axis ball screw with respect to the X1-axis direction to restrict movement of the X1-axis ball screw in the X1-axis direction. The tool post is provided with an X1-axis ball screw nut engaged with the X1-axis ball screw. The X1-axis ball screw nut is movable in the X1-axis direction according to rotation of the X1-axis ball screw. The direction that the X1-axis ball screw nut approaches the X1-axis support bearing faces the same direction as the direction that the tool cuts into the workpiece.

A mechanism for machining a workpiece includes a fixing base, a driving member, a connecting member, a cutter, a first guiding sleeve, and a spring. The driving member is positioned above the fixing base. The connecting member is coupled to the driving member. One end of the cutter is fixed to the connecting member, and the cutter is passed through the fixing base to machine the workpiece positioned under the fixing base. The spring is positioned between the connecting member and the fixing base. The spring is compressed when the driving member drives the cutter away from the fixing base to machine the workpiece, and the spring restores to bring the cutter back toward the fixing base after the machining.

A processing mechanism for machining a workpiece includes a fixing base, a driving member, a connecting member, a cutter and a spring. The driving member is positioned above the fixing base. The connecting member is coupled to the driving member. One end of the cutter is fixed to the connecting member, and the cutter can be driven to pass through the fixing base to machine the workpiece positioned under the fixing base. The spring is positioned between the connecting member and the fixing base. The spring is compressed when the driving member drives the cutter away from the fixing base to machine the workpiece, and the spring under compression biases the cutter back toward the fixing base. The disclosure also supplies a processing device using the processing mechanism.

A control device includes a control part which generates a torque command based on a resultant command, which is obtained by adding a position deviation, which is the difference between a position command and the actual position of a feed shaft, to an oscillation command to control the feed shaft, and an elastic deformation amount calculation part which calculates the elastic deformation amount of a structure composed of a tool or workpiece and the feeding mechanism therefor based on the torque command. An oscillation command generation part generates the above oscillation command based on the rotation speed of the workpiece, the position command of the feed shaft, and the above elastic deformation amount.

A turning method includes driving a first movement apparatus to locate a cutting edge of a turning tool at a first radial position; driving a second movement apparatus to move the turning tool in an axial direction to perform first turning with the cutting edge at the first radial position; driving the second movement apparatus to move the turning tool away from a workpiece in the axial direction after performing the first turning; calculating an error between the processed dimension and a target dimension; driving a third movement apparatus, which is configured to move the turning tool relative to the first movement apparatus in a radial direction, to locate the cutting edge of the turning tool at a second radial position to correct the error; and driving the second movement apparatus to move the turning tool in the axial direction to perform second turning at the second radial position.