Patent Publication Number: US-2021187669-A1

Title: Light shield and laser processing system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based on and claims priority to Japanese Patent Application No. 2019-232861 filed on Dec. 24, 2019, the content of which is incorporated herein by reference in its entirety. 
     FIELD 
     The present disclosure relates to a light shield and a laser processing system. 
     BACKGROUND 
     A laser processing device is known in which a laser light emitting head or a workpiece is mounted to a robot and the workpiece is processed with laser light (e.g., see Japanese Unexamined Patent Application, Publication No. 2008-114458). 
     To shield laser light of this laser processing system not to be emitted outside, the laser processing system including the whole body of the robot is surrounded with a light shield. 
     SUMMARY 
     An aspect of the present disclosure is a light shield that houses a space where a workpiece is disposed during laser processing performed by a robot with the workpiece or a laser emitting device mounted on a tip of a wrist of the robot, the light shield including a plurality of shield members capable of forming a closed space by being combined, wherein at least one of the shield members is provided to be movable between a state where the shield member is away from another shield member of the shield members and a state where the shield member is combined with the other shield member, and an opening configured to allow a part of the robot to pass without a gap is defined at a position of a boundary between the two shield members that are combined. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is an overall configuration diagram showing a laser processing system according to an embodiment of the present disclosure. 
         FIG. 2  is a perspective view showing an opened state of a light shield according to the embodiment of the present disclosure provided in the laser processing system of  FIG. 1 . 
         FIG. 3  is a perspective view showing a closed state of the light shield of  FIG. 2 . 
         FIG. 4  is an overall configuration diagram showing a state where the light shield of the laser processing system of  FIG. 1  is closed to perform laser processing. 
         FIG. 5  is a perspective view showing an opened state of a modification of the light shield of  FIG. 2 . 
         FIG. 6  is a perspective view showing a closed state of the light shield of  FIG. 5 . 
         FIG. 7  is a front view of the light shield of  FIG. 5 . 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Hereinafter, description will be made as to a light shield  4  and a laser processing system  1  according to an embodiment of the present disclosure with reference to the drawings. 
     As shown in  FIG. 1 , the laser processing system  1  according to the present embodiment is provided with a robot  2  having a tip of a wrist unit (a wrist)  10  to which a workpiece W is mounted, a laser processing device  3  that processes the workpiece W with laser light, a light shield  4  according to the present embodiment, and a controller  5  that controls these components. 
     The robot  2  is, for example, a vertical 6-axis articulated robot. The robot  2  includes a base  6  fixed to a floor surface F, a swivel body  7  supported rotatably about a vertical first axis to the base  6 , and a first arm  8  supported swingably about a horizontal second axis to the swivel body  7 . 
     Furthermore, the robot  2  includes a second arm  9  supported rotatably about a horizontal third axis to the first arm  8 , and a three-axis wrist unit  10  is attached to a tip of the second arm  9 . 
     As shown in  FIG. 1  to  FIG. 3 , the light shield  4  according to the present embodiment is provide with an upper box member (a shield member)  11  and a lower box member (a shield member)  12  that are combined to form a rectangular parallelepiped box body, and an opening/closing mechanism  13  that opens and closes these members. The upper box member  11  and the lower box member  12  are composed of a material that can shield the laser light. 
     As shown in  FIG. 2 , the upper box member  11  is provided with a rectangular top plate  11   a  and four side walls (wall surfaces)  11   b  extending vertically downward from four sides of the top plate  11   a , and is formed in a box shape that does not include a bottom plate. 
     As shown in  FIG. 2 , the lower box member  12  is provide with a bottom plate  12   a  having about the same shape as the top plate  11   a  and four side walls (wall surfaces)  12   b  extending vertically upward from four sides of the bottom plate  12   a , and is formed in a box shape that does not include the top plate. 
     A lower edge (a boundary) of one of the side walls  11   b  of the upper box member  11  is provided with a semicircular cutout  14  at a center position of the lower edge in a width direction. 
     Furthermore, an upper edge (a boundary) of one of the side walls  12   b  of the lower box member  12  is provided with a semicircular cutout  15  at a center position of the upper edge in the width direction. 
     A radius of the cutout  14 ,  15  is, for example, slightly larger than a radius of a flange  31  of the tip of the wrist unit  10  of the robot  2 . An elastic member  16 ,  17  such as a sponge rubber that is elastically deformable when pressed is disposed over a whole circumference of an inner edge of the cutout  14 ,  15 . The elastic member  16 ,  17  is also composed of a material that can shield the laser light. 
     The upper box member  11  and the lower box member  12  are arranged at positions where the lower edge of the upper box member  11  and the upper edge of the lower box member  12  butt against each other, and the semicircular cutout  14  of the upper box member  11  and the semicircular cutout  15  of the lower box member  12  are arranged at positions where the cutouts butt against each other to form a round opening  30 . 
     As shown in  FIG. 4 , the upper box member  11  and the lower box member  12 , when combined, is of sufficient size that a hand  18  attached to the tip of the wrist unit  10  of the robot  2  and the workpiece W grasped with the hand  18  can be housed and rotated inside. 
     The opening/closing mechanism  13  includes an upper direct drive mechanism  19  that raises and lowers the upper box member  11 , and a lower direct drive mechanism  20  that raises and lowers the lower box member  12 . The upper direct drive mechanism  19  is, for example, an air cylinder, and raises and lowers the upper box member  11  attached to a tip of a rod in a vertical direction between a lower end position where it butts against the lower box member  12  and an upper end position where it is disposed vertically above the lower end position. 
     The lower direct drive mechanism  20  is also, for example, an air cylinder, and raises and lowers the lower box member  12  attached to a tip of a rod in a vertical direction between an upper end position where it butts against the upper box member  11  and a lower end position where it is disposed vertically below the upper end position. 
     The laser processing device  3  includes a laser oscillator  21  that generates the laser light, and a scanner  22  that scans the laser light emitted from the laser oscillator  21 . The scanner  22  is fixed to an upper part of the top plate  11   a  of the upper box member  11 . The top plate  11   a  is provided with a through portion  23  through which the laser light output from the scanner  22  passes into the upper box member  11 . The laser oscillator  21  is connected to the scanner  22  by an optical fiber  24 , and the laser light emitted from the laser oscillator  21  enters the scanner  22  via the optical fiber  24 . 
     Hereinafter, description will be made as to operations of the light shield  4  and the laser processing system  1  according to the present embodiment having such a configuration. 
     To perform laser processing of the workpiece W by use of the laser processing system  1  according to the present embodiment, the controller  5  actuates the opening/closing mechanism  13  to move the upper box member  11  to the upper end position and the lower box member  12  to the lower end position, as shown in  FIG. 2 . As a result, a sufficient gap is made between a lower end of the upper box member  11  and an upper end of the lower box member  12 . 
     Next, the controller  5  actuates the robot  2  to grasp the workpiece W with the hand  18 . As shown in  FIG. 1 , the grasped workpiece W is disposed in the gap between the upper box member  11  and the lower box member  12 . 
     In this state, the controller  5  actuates the opening/closing mechanism  13  to move the upper box member  11  to the lower end position and the lower box member  12  to the upper end position, as shown in  FIG. 3 . This causes the lower edge of the upper box member  11  and the upper edge of the lower box member  12  to butt against each other, sealing the space therebetween, and the light shield  4  made of a rectangular parallelepiped box body is formed. 
     At this time, the semicircular cutout  14  formed in the lower edge of the upper box member  11  and the semicircular cutout  15  formed in the upper edge of the lower box member  12  are combined to form the round opening  30 . As shown in  FIG. 4 , the flange  31  of the tip of the wrist unit  10  of the robot  2  passes through the formed opening  30 . The elastic members  16 ,  17  are arranged in the cutouts  14 ,  15 , and hence the elastic members  16 ,  17  are pressed onto an outer peripheral surface of the flange  31  and accordingly elastically deformed, to fill the gap between the cutouts  14 ,  15  and the outer peripheral surface of the flange  31 . 
     In this state, the hand  18  attached to the tip of the wrist unit  10  of the robot  2  and the workpiece W grasped with the hand  18  are housed in the light shield  4 . The flange  31  of the robot  2  is made to pass through the opening  30  formed in the light shield  4 , so that only a tip shaft can be rotated without changing relative positions of the flange  31  and the opening  30 . This allows the workpiece W to be rotated inside the light shield  4 . 
     Then, the controller  5  controls the laser processing device  3 , to irradiate a desired position on the workpiece W with the laser light emitted from the laser oscillator  21  by the scanner  22  as shown in  FIG. 4 , so that the laser processing can be performed to the workpiece W. 
     In this case, since the workpiece W is covered with the light shield  4 , the laser light can be more reliably prevented from leaking to outside. 
     That is, according to the laser processing system  1  of the present embodiment, a region including the whole body of the robot  2  is not surrounded with the light shield  4 , but only a region including the tip of the wrist unit  10  of the robot  2  and the workpiece W is surrounded with the light shield  4 . This has an advantage that the whole laser processing system  1  does not need to be increased in size. 
     In the present embodiment, the upper box member  11  and the lower box member  12  are moved in an up-down direction by the opening/closing mechanism  13 . Alternatively, the members may be moved in an arbitrary direction, for example, in a horizontal direction. Furthermore, the air cylinder is employed as the opening/closing mechanism  13 . Alternatively, a direct drive mechanism provided with a motor and a ball screw or another actuator may be employed. 
     Furthermore, both the upper box member  11  and the lower box member  12  are moved. Alternatively, one of these members may be fixed, and only the other member may be moved. 
     Additionally, in the present embodiment, the upper box member  11  and the lower box member  12  including the semicircular cutouts  14 ,  15  are employed. Alternatively, in place of the wall surfaces  11   b ,  12   b  of the upper box member  11  and the lower box member  12  in which the opening  30  is formed, as shown in  FIG. 5  to  FIG. 7 , wall surfaces may be employed on which a plurality of band plate-shaped strip members (longitudinal members)  25 ,  26  extending in a moving direction of the upper box member  11  and the lower box member  12  are arranged adjacent to one another in a width direction without a space. 
     The respective strip members  25 ,  26  are each provided movable in the moving direction (a longitudinal direction) of the upper box member  11  and the lower box member  12 . As shown in  FIG. 7 , the strip members are urged in directions toward tips that form boundaries, by springs (urging mechanisms)  27 ,  28 . 
     Therefore, the lower edge of the upper box member  11  and the upper edge of the lower box member  12 , with nothing in between, are pushed by the springs  27 ,  28 . Consequently, as shown in  FIG. 5 , the strip members are linearly aligned, respectively. 
     Furthermore, in the tips of the respective strip members  25 ,  26 , elastic members (elastic bodies)  29   a ,  29   b  composed of a sponge rubber or the like are arranged to be elastically deformable in accordance with an outer surface shape of the robot  2 . 
     Then, when the lower edge of the upper box member  11  and the upper edge of the lower box member  12  are brought close to each other with the flange  31  of the robot  2  is placed between the edges, the strip members  25 ,  26  of the portions in contact with the flange  31  are pushed against urging forces of the springs  27 ,  28  and moved in the longitudinal direction, as shown in  FIG. 6  and  FIG. 7 . Accordingly, as the upper box member  11  and the lower box member  12  come close to each other, an opening  30  surrounding the flange  31  is formed following a shape of the flange  31 . Therefore, only the region including the tip of the wrist unit  10  of the robot  2  and the workpiece W can be subjected to laser processing while being surrounded with the light shield  4  in the same manner as described above. 
     According to this structure, the opening  30  is formed by pressing the edges of the strip members  25 ,  26  against the outer peripheral surface of the flange  31  of the robot  2 , and hence a position where the flange  31  is interposed can be freely set in the width direction of the strip members  25 ,  26 . In this case, it is preferable that the strip members  25 ,  26  have a comparatively small width dimension, because the opening  30  can be accurately formed in the outer peripheral surface of the flange  31  of the robot  2 . 
     In place of the springs  27 ,  28  that urge the strip members  25 ,  26 , a direct drive mechanism including a motor and a ball screw may be employed, and the controller  5  may control each motor based on positional information of the robot  2  to change a position of the opening  30 . This allows the position of the opening  30  to be changed, while moving the robot  2 , and a posture of the workpiece W can be more freely changed. 
     Furthermore, the wall surfaces  11   b ,  12   b  on which the strip members  25 ,  26  are arranged do not have to be provided only on one surface, and may be provided on two surfaces or more. Additionally, to form the opening  30  that accurately follows the shape of the outer peripheral surface of the flange  31  of the robot  2 , pins having a small diameter and a round cross section may be arranged and formed in place of the strip members  25 ,  26 . 
     Additionally, in the present embodiment, the flange  31  of the robot  2  is made to pass through the opening  30  formed in one wall surface of the upper box member  11  and the lower box member  12 . Alternatively, an arbitrary position of the robot  2  may be opened. However, in order to pass the flange through the opening  30  having a defined shape or the opening  30  formed by moving the strip members  25 ,  26 , it is preferable that the opening is a portion having a simply round, elliptic or another cross sectional shape. With the simple shape, the light shield  4  can be more reliably formed without any gaps by elastic deformation of the elastic member  16 ,  17 ,  29   a , or  29   b.    
     Furthermore, in the present embodiment, it has been illustrated that the workpiece W is grasped with the hand  18  attached to the tip of the wrist unit  10  of the robot  2 . Alternatively, the present invention may be applied to a case where the workpiece W is disposed within the light shield  4 , and a laser emitting device is supported on the robot  2 .