Machine tool, position information correction method, and position information correction program

1 . A machine tool comprising:

a spindle configured to rotatably grip a workpiece;

a turret configured to mount a tool for processing the workpieces;

a movable body configured to move independently from the spindle and the turret;

a contact type sensor configured to move in accordance with a movement of the movable body; and

a controller configured to calculate center position information indicating a center position of the spindle based on spindle position information acquired via the sensor moved to the vicinity of the workpiece by moving the movable body, wherein

the sensor has a cylindrical support member and a detector, and the detector having a plurality of contacts includes four contacts arranged separated by 90 degrees each at a circumferential surface of the support member,

the controller acquires first position information indicating an upper end position of the workpiece, second position information indicating a left end position of the workpiece, third position information indicating a lower end position of the workpiece, and fourth position information indicating a right end position of the workpiece, as the spindle position information by moving the movable body to bring the detector into contact with the workpiece, and

the controller acquires cutting edge position information indicating a position of a cutting edge of the tool via the sensor by moving the movable body, and corrects the cutting edge position information based on the center position information.

2 . The machine tool according to claim 1 , wherein the controller acquires the cutting edge position information by moving the movable body so that the center position of the sensor is conformed to the center axis of the spindle, and contacting the cutting edge of the tool with the sensor by moving the turret.

3 . The machine tool according to claim 2 , wherein the step for moving the movable body so that the center position of the sensor is conformed to the center axis of the spindle includes a step for moving the movable body so that the center axis of the support member is conformed to the center axis of the spindle.

4 . The machine tool according to claim 3 , wherein a distance between the pair of contacts arranged 180 degrees apart included in the four contacts is the same as the diameter of the workpiece.

5 . The machine tool according to claim 1 , wherein the movable body is a rear spindle arranged so as to face the spindle.

6 . A position information correction method for a machine tool having

a spindle configured to rotatably grip a workpiece;

a turret configured to mount a tool for processing the workpieces;

a movable body configured to move independently from the spindle and the turret;

a contact type sensor configured to move in accordance with a movement of the movable body; and

a controller configured to calculate center position information indicating a center position of the spindle based on spindle position information acquired via the sensor moved to the vicinity of the workpiece by moving the movable body,

wherein the sensor has a cylindrical support member and a detector, and the detector having a plurality of contacts includes four contacts arranged separated by 90 degrees each at a circumferential surface of the support member, executed by the controller:

acquiring first position information indicating an upper end position of the workpiece, second position information indicating a left end position of the workpiece, third position information indicating a lower end position of the workpiece, and fourth position information indicating a right end position of the workpiece, as the spindle position information by moving the movable body to bring the detector into contact with the workpiece, and

acquiring cutting edge position information indicating a position of a cutting edge of the tool via the sensor by moving the movable body; and

correcting the cutting edge position information based on the center position information.

7 . A computer-readable recording medium having stored therein a position information correction program for a machine tool having

a spindle configured to rotatably grip a workpiece;

a turret configured to mount a tool for processing the workpieces;

a movable body configured to move independently from the spindle and the turret;

a contact type sensor configured to move in accordance with a movement of the movable body, wherein the sensor has a cylindrical support member and a detector, and the detector having a plurality of contacts includes four contacts arranged separated by 90 degrees each at a circumferential surface of the support member; and

a controller configured to calculate center position information indicating a center position of the spindle based on spindle position information acquired via the sensor moved to the vicinity of the workpiece by moving the movable body, for causing the controller to execute a process comprising:

acquiring first position information indicating an upper end position of the workpiece, second position information indicating a left end position of the workpiece, third position information indicating a lower end position of the workpiece, and fourth position information indicating a right end position of the workpiece, as the spindle position information by moving the movable body to bring the detector into contact with the workpiece; and

acquiring cutting edge position information indicating a position of a cutting edge of the tool via the sensor by moving the movable body; and

correcting the cutting edge position information based on the center position information.