JPH0434164B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for bending a plate-shaped work by combining a press brake and an articulated playback type industrial robot.

When a playback type industrial robot (hereinafter abbreviated as robot) is used to abut a workpiece against a limit gauge such as a backgauge installed in a press brake, each work point is taught in advance so that the workpiece is abutted against the limit gauge. You have to try to hit it.

However, there may be a slight deviation in the teaching points visually observed by the operator, and it may not be possible to turn on the limit gauge. In order to avoid this situation, the speed of the robot is slowed down and the number of teaching points near the end of the collision is increased.

In this conventional method, a large number of teaching points must be taught very carefully, which requires a lot of effort and a lot of time for both teaching and playback, and also relies heavily on the visual observation of the teaching operator. There were drawbacks that worsened product accuracy.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a sheet material bending apparatus that can shorten teaching time, simplify teaching operations, and improve product accuracy.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an overall side view showing the correspondence between the press brake and the robot, and FIG. 2 is a side view for explaining the workpiece butting operation. FIG. 3 shows a flow chart for robot control. FIG. 4 is an enlarged explanatory view of the buffer spring.

The correspondence relationship between the press brake and the robot will be explained with reference to FIGS. 1 and 2.

In FIG. 1, reference numeral 1 denotes a press brake comprising upper and lower molds for bending a plate-shaped workpiece W, and a robot 3 is disposed in front of this press brake 1. The robot 3 has a suitably large number of joints, and grasps a workpiece 5 with fingers 7. A buffer spring S is provided on the finger. The figure shows the state just before the end of the butting work. As shown in the block diagram, the robot 3 has a computer 9 and a storage device.
The robot's CPU 15 is controlled to execute the data in the RAM 11 in the storage device ROM 13 according to the procedure.
A servo mechanism _M3 of the robot is driven through a pulse distributor 17 and an amplifier 19. Further, the results of driving the robot 3 are returned to the pulse distributor 17 for feedback control.

The press brake is also equipped with a computer 21, and the CPU 25 positions the limit gauge 23 that determines the end position of the workpiece and performs bending operations, etc.
It is controlled by. For example, a limit switch is used as the limit gauge 23, and is adjusted by moving left or right in the figure depending on the type of workpiece 5. An example is shown in which both the gauge movement motor M ₁ and the bending operation motor M ₂ are controlled by pulse motors.

The operation will be explained using the flowchart of FIG. 3 while referring to FIGS. 1 and 2.

The workpiece 5 is gripped by the fingers 7 of the robot 3 via the buffer spring S, and brought to the top (or near) of the workbench (mold) 27 of the press brake 1. Let this point be A (see Figure 2). Point A is a position where the workpiece 5 can be brought to the end point C of the abutting operation where the limit gauge 23 is located by simply advancing the workpiece 5. Point A and point C are stored in the robot storage device RAM 11 by direct teaching.

FIG. 3 shows a flowchart in which a service code that repeats advance and signal sensing from point A to point C is inserted at the start point of the abutting operation.

The robot carries the tip of the workpiece to point A (step 101). In step 102, the robot is advanced 1 mm to point B. The forward distance lmm is an arbitrary dimension of the straight forward distance in which the workpiece cannot hit the limit gauge, and is determined, for example, to be 10 mm. The subsequent forward movement is performed in small steps of △lmm until the terminal point C. Steps to wait for a signal from the limit switch
103 shows. The signal sense ON by the limit switch 23 indicates that the abutment has been completed, and the signal sense OFF indicates that the abutment has not yet been completed.

If it is determined that the signal from the limit switch is off, the process moves from step 104 to step 107.

At step 107, a command to advance △lmm, for example 2mm, is issued. The end point determination in step 108 is to determine whether the teaching end point C described above has been reached. If it has not yet been reached, the answer is NO and the process returns to step 103, where the limit switch signal is held again. The signal wait time is, for example, 20 msec, and this time can be changed freely.

Steps 103 → 104 → 107 → 108 → 103 are repeated several times, and when it is determined that the signal sense is on in step 104, the process moves to step 105, and after a pause, step 106
The next processing, for example, indicates that the robot 3 removes the workpiece 5 from the finger 7, moves backward, and hands over the work to the press brake. At the time of collision, robot 3
pushes workpiece 5 by a maximum of △lmm. The buffer spring S provided on the finger 7 of the robot is provided in order to absorb this pressing force of Δlmm and to prevent excessive force from being applied to the robot, workpiece, and press brake.

The switch was not turned on at step 104 and the step
It is conceivable that the process moves to step 107, advances by Δlmm, determines the end point in step 108, and moves to another process in step 109. This condition occurs due to dimensional errors in the workpiece. In step 109, this work is transferred to a table separately provided on the side of the press brake, and processing such as counting the number of defective products or generating an alarm is performed.

In the next process shown in step 106, when the limit switch 23 is turned on, a signal is input to the input interface 29 of the robot to stop the robot. Next, the robot output interface 3
1 to press brake input interface 33
The press brake 1 lowers the upper die by driving the motor _M2 , and places the workpiece 5 between it and the lower die.
Clamp and fix. This fixation of the workpiece 5 can be easily detected by detecting load fluctuations of the motor _M2 , similar to pressure fluctuations in a normal hydraulic press brake. The press brake that has fixed the workpiece notifies the robot through the output interface 35 that the workpiece has been fixed, and causes the robot to move backward. Thereafter, the press brake 1 performs the bending operation under the control of the computer 21.

According to the above flowchart, only two teaching points, point A and point C, need be given instead of the conventional teaching of many points.

Advance distance lmm, speed from work start point A, minute feed step Δlmm, etc. can be freely changed by programming. Therefore, it is easy to teach,
Each product can be dealt with immediately.

As can be understood from the above description of the embodiments, the present invention is provided with upper and lower molds for bending a plate-shaped workpiece 5, and the workpiece 5 is
A press brake 1 includes a limit gauge 23 whose position is freely adjustable in the front and back direction and which positions the work 5 with respect to the mold by abutting one end of the press brake 1. A multi-jointed robot 3 is equipped with a finger 7 for grasping the end side, and a press brake 1 is applied to bend the workpiece 5 after detecting that one end of the workpiece 5 has come into contact with the limit gauge 23. The computer 21 that controls stops the robot 3 when it detects that one end of the workpiece 5 has come into contact with the limit gauge 23, and is informed by the computer 21 that the workpiece 5 is fixed to the press brake 1. A computer 9 that controls the robot 3 to release the grip on the workpiece 5 and move backward later, and absorbs the slight amount of pressure Δl of the workpiece 5 when the workpiece 5 comes into contact with the limit gauge 23. The finger 7 is provided with a buffer spring S.

As is clear from the above configuration, the present invention relates to a bending device formed by combining a press brake 1 and a robot 3, and the computer 21 that controls the press brake 1 is equipped with a Work 5 on limit gauge 23
The computer 9 that controls the robot 3 controls the press brake 1 after detecting that one end has abutted against the limit gauge 2.
When the robot 3 detects that the workpiece 5 has come into contact with the press brake 1, the robot 3 is stopped, and after being notified of the fixation of the workpiece 5 by the computer 21 that controls the press brake 1, the robot 3 releases the workpiece 5 and moves backward. The finger 7 of the robot 3 is equipped with a buffer spring S that absorbs the pressing amount Δl of the workpiece 5.

Therefore, according to the present invention, the point at which the workpiece 5 is gripped by the finger 7 of the robot 3 is appropriately positioned at the position of the mold, and the work of abutting the workpiece 5 against the limit gauge 3 is started. To facilitate the teaching and accurately position the workpiece 5 to perform the bending process when the workpiece 5 is bent by teaching and moving the workpiece 5 by a predetermined amount in the direction of a limit gauge 3 and brought into contact with the limit gauge. It is something that can be done.

[Brief explanation of drawings]

FIG. 1 is an overall side view showing the correspondence between the press brake and the robot, and also shows a control block diagram. Figure 2 is a side view explaining the positional relationship, Figure 3
The figure is a flowchart for control, and FIG. 4 is a side sectional view of the buffer spring. 1...Press brake, 3...Robot, 5...
...Work, 15...Robot CPU, 23...Limit gauge.

Claims (1)

[Claims] 1 Equipped with upper and lower molds for bending a plate-shaped workpiece 5, and a limit gauge 23 for positioning the workpiece 5 with respect to the mold by abutting one end of the workpiece 5, the position of which can be adjusted in the front and back direction. A press brake 1, an articulated robot 3 having a finger 7 disposed in front of the press brake 1 and gripping the other end of the work 5, and a limit gauge 23 that holds one end of the work 5. a computer 21 that controls the press brake 1 to bend the workpiece 5 after detecting that the press brake has come into contact with the press brake; and the limit gauge 23.
The computer 2 stops the robot 3 when it detects that one end of the workpiece 5 has come into contact with the press brake 1, and the computer 2
A computer 9 controls the robot 3 to release the grip on the workpiece 5 and move backward after being informed by the robot 1.
and the finger 7 is provided with a buffer spring S that absorbs a slight amount of pressure Δl of the workpiece 5 when the workpiece 5 comes into contact with the limit gauge 23. Bending equipment.