Method for teaching a machining line

#1. Field of the Invention:

#The present invention relates to a method capable of automatic teaching of a machining line, which is used in a machining apparatus.

#2. Description of the Prior Art:

#Various other objects, features and attendant advantages of the present invention will readily be appreciated as the same becomes better understood by reference to the following detailed description of a preferred embodiment when considered in connection with the accompanying drawings, in which:

#FIG. 1 is a schematic view of a laser machining apparatus according to the present invention;

#FIG. 2 is a sectional chart of the borderline sensor shown in FIG. 1;

#Referring now to the drawings, FIG. 1 illustrates a laser machining apparatus constructed in accordance with a first embodiment of the present invention.

#A first rail member 12 is guided by rails 10, 11 and is moved along the first axis (i.e., X axis) by a servomotor. A carrier 13 is mounted on the rail member 12 and is moved along the second axis (i.e., Y axis) by a feed screw 14 driven by a servomotor M2. On one side of the carrier 13, a moving head 16 is mounted and is moved along the third axis (i.e., Z axis). A wrist 15 which swings about the fourth, fifth and sixth axes is mounted at the lower end of the moving head 16. On the wrist 15, a machining tool T such as a laser torch for a emitting laser beam and a borderline sensor S are mounted. Numeral 1 indicates a laser exciting apparatus, and a laser beam emitted by the laser exciting apparatus 1 is led to the carrier 13 with mirrors 2, 3, 4 and beam guides 5, 6 so that the laser beam is emitted from the machining tool T against a workpiece W.

#FIG. 2 shows the structure of the borderline sensor S. A light emitting device 16 for emitting a light beam against the workpiece W and a light receiving device 17 for detecting a light beam reflected from the workpiece W are mounted on the sensor S. The borderline sensor S outputs an on-off signal based upon the amount of reflected light beam which is received by the light receiving device 17 in order to detect a borderline K on the workpiece W. Namely, the working surface of the workpiece W is divided into two zones by the borderline K corresponding to a machining line, and one of the two zones is colored with black paint, as shown in FIG. 3(a), so that one zone becomes a dark zone L and another zone becomes a bright zone M. The light receiving device 17 detects the borderline K based upon the change in the reflected light beam between the dark zone L and the bright zone M, and changes the status of the output signal as shown in FIG. 3(b).