JPH02284721A - Bending angle corrector for bending machine - Google Patents

Abstract

PURPOSE:To select adequate bending condition at the time of bending the work between upper and lower dies by picking up the image of the end face shape of the work, detecting the present bending angle of the work in accordance with the picked up image and correcting the angle so as to attain the preset target bending angle. CONSTITUTION:A punch holder 13 and a punch 17 (upper die) as well as a die holder 15 and a die 19 (lower die) are mounted onto a body frame 11 on a base 3 of a swinging press 1. The work W is clamped by clamp jaws 23 of a robot arm 21. Visual sensors 27, 29 mounted to the frame 11 pickup the images of the sectional shape. The present bending angle is then corrected to the preset bending angle via an image processor 33 and an NC unit 31 which controls the operations of the press and the robot. The detection and correction of the deviation in the clamping and further, the detection and correction of the bending angle are automatically executed in this way and the high-accuracy bending is automatically executed.

Description

Detailed Description of the Invention [Object of the Invention] (Industrial Application Field) The present invention relates to a bending angle correction device for a bending machine.

(Prior Art) In bending workpieces, especially sheet metal, it takes time and effort to adjust the pressing force to obtain a target bending angle or to adjust clamping displacement when clamping the workpiece. Conventionally, the pressure force was adjusted manually by repeatedly performing trial bending.

(Problem to be solved by the invention) By the way, in pursuit of bending precision in the trend of higher precision sheet metal processing, "C. Variations between workpieces, especially differences in rolling direction and lot differences. Errors in bending angle due to variations such as these cannot be ignored.Therefore, there is currently no means to easily resolve this error in bending angle, which is a bottleneck in achieving higher precision.

In particular, for high-precision robot cells suitable for high-mix, low-volume production, adding processes such as trial bending is contrary to the purpose of the cell.

In addition, a high-precision robot clamps the workpiece,
In a cell that automatically bends a workpiece in cooperation with a bending machine, workpiece positioning errors due to clamp misalignment during workpiece clamping cannot be ignored, and the impact on processing accuracy cannot be ignored.

The purpose of this invention is to provide a bending machine with a bending angle correction function.
To provide a bending angle correcting device for a bending workpiece, which also serves as a workpiece position correction function during workpiece crank 1 and can automatically perform high-precision bending work.

[Structure J of the Invention (Means for Solving the Problem 1) In order to achieve the above object, the present invention provides a bending method in which a workpiece interposed between a bunch and a die is bent using both metals 717. A bending angle correction device of a processing machine includes an appropriate number of imaging means for imaging the end face shape of the workpiece, and a current bending angle of the workpiece based on the image of the end face shape of the workpiece taken by the imaging means. A bending angle detecting means for detecting a bending angle, a bending angle correcting means for correcting the bending angle so that the current bending angle detected by the bending angle detecting means becomes a preset target bending angle, and a bending angle correcting means for correcting the bending angle so that the current bending angle detected by the bending angle detecting means becomes a preset target bending angle. A bending angle correction device for a bending machine is provided with a bending force correction means for automatically correcting the bending force based on the corrected bending angle obtained.

Further, the present invention provides the bending angle correction device, further comprising a workpiece clamping means for clamping the workpiece, an imaging means for taking an image of the workpiece clamped by the workpiece clamping means and positioned, and a workpiece imaged by the imaging means. a workpiece tip position detection means for detecting the current tip position of the workpiece based on the workpiece image; The apparatus is equipped with a workpiece position correction means for correcting the position of the workpiece.

(Function) By adopting the bending angle correction device of the bending machine of the present invention, when bending a workpiece interposed between the upper mold and the lower mold by using both molds, the image capturing An image of the end face shape of the workpiece bent by the means is taken. The current bending angle is detected by the bending angle detection means based on the end face shape (bent shape) of the workpiece imaged by the imaging means.

The current bending angle detected by the bending angle detection means and the preset target bending angle are used to calculate a corrected bending angle by the bending angle correction means. The bending pressure force correction means is activated by the corrected bending angle obtained by the bending angle correction means and the bending pressure force is corrected, so that the current bending angle is automatically changed to the target bending angle and high precision bending processing is performed. It will be done.

Further, when performing the bending process, the workpiece is clamped and positioned by the workpiece clamping means.

After being positioned, the ml imaging means takes an image of the tip position of the workpiece. The current tip position of the workpiece is detected by the workpiece tip position detection means based on the term of the cotton tip device imaged by the imaging device.

Based on the detected current tip position of the workpiece and the preset target tip position, the workpiece position correction means automatically corrects the current tip position to the 1'' marker y7H position.

By performing the above-described bending angle correction after correction by this workpiece position correction means, there is no clamping displacement of the soak and highly accurate bending is performed.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

Examples of the bending machine include a press brake, a two-way press brake, and a swinging press (7), but the present invention will be explained by taking the swinging press as an example.

Referring to FIG. 11, in the swinging brace 1, a frame 5 is integrally extended in the vertical direction at the center of both sides of the base 3. At the upper part of this frame 5, a U-shaped bracket 1 7 is pivotally supported by a pin 9.

A C-shaped main body frame 11 is rotatably provided on the bracket 17. A punch holder 13 and a die boulder 15 are attached to the left side of the main body frame 11 in FIG. 11, respectively. A bunch 17 as an upper mold is mounted on the bunch holder 13 so as to be able to reciprocate, for example. A die 19 serving as a lower mold is fixedly attached to the die holder 15.

Note that the bamboo 17 may be fixed to the punch holder 13 and the die 19 may be attached to the die holder 15 so as to be able to reciprocate.

Above the main body frame 11, a robot arm 21, a part of which is omitted, is installed, for example, as shown in FIG. ing. A work clamp bar 25 equipped with a clamp jaw 23 for clamping the work W is attached to the tip of the robot arm 21.

With the above configuration, the workpiece clamper 25 is clamped by the clamp jig 3''-23 attached to the tip of the robot arm 21, and the punch holder 13. It is positioned between a bunch 17 and a die 19 mounted via a die holder 15, and the desired bending process is performed on the work W by the cooperation of the bunch 17 and die 19.

The body frame 11 is equipped with a CO as an imaging means, for example.
Visual sensors 27 and 29 from a D camera or the like are attached. As shown in FIGS. 9 and 10, the visual sensors 27 and 29 are installed on the main body frame 11 so as to pass through the bending center axis A so that the cross-sectional shape of the workpiece W can be imaged. In addition, a lens 2 is provided in front of the visual sensors 27 and 29.
7A.

29A is provided. Through these lenses 27Δ and 29A, the areas of visual fields 1 and 2 are projected as shown in FIG. Make sure both cross sections are included.

In FIGS. 9 and 10, two visual sensors 27.2
9 are lined up, but it does not matter if there is one or three or more. In this embodiment, two visual sensors 27 and 29 are used.
We will explain the case using .

An NC device 31 is connected to the swinging brace 1 and the robot arm 21, and this NC device 31 controls the swinging brace 1 and the robot arm 2.
1 is operated by numerical control and 5 B. An image processing device 33 is connected to the visual sensor 27, 29,
Further, the NC device 31 and the display device 35 are connected to the image processing device 33 .

With the above configuration, an image of the cross-sectional shape of the workpiece W imaged by the visual pins +j27 and 29 is outputted to the image processing device 33 as a video signal. 1iIiii The measurement results are fed back from the image processing device 33 to the NC stomach 31.

A configuration control block diagram of the image processing device 33 is shown in FIG. In FIG. 1, the image processing device 33 includes a switch 37 that selects a video signal of the cross-sectional shape of the workpiece W imaged by the visual sensors 27 and 29, an A/D converter 39 that converts the video signal into digital data, and an A/D converter 39 that converts the video signal into digital data. Frame memory 41 for storing digital signals, CPU 43. ROM45. RAM
47 and l1049.

This l1049 is the "1 standard bending angle" that is input and set by the NG device 31 removal device β.

The target workpiece tip position is temporarily stored.

With the above configuration, the video signals from the visual sensors 27 and 29 are selected by the switch 37 and sent to the A/D converter 39.
The data is digitized and stored in the frame storage 41. C P U 4. 3, in accordance with the bending angle detection command from the NC device 31, the following bending angle detection algorithm is executed, and the workpiece W stored in the frame memory 41 is
The bending angle of the work W is detected from the image data of the bending cross section, and this result is sent to the NC device 31 via 1/04.9.
Or it will be output to the display 35.

Also, according to the clamp deviation detection command from the NC device 31, the clamp deviation detection algorithm is executed in the next step, and the clamp deviation of the image data J = rework W stored in the frame memory 41 is detected. Then, this result is output to the NC device 31 or the display 35.

Next, the bending angle detection method will be explained. As shown in FIG. 2, both bending sections of the workpiece W are created at the visual sensor ++27.29. Figure 3.

As shown in FIG. 4, in each image, the approximate straight line Ml, 2 of the bent cross-sectional image is determined, and the angle θ1. Detect θ2.

Taking into account the installation angle difference α between the visual sensors 27 and 29, which was measured in advance when the visual sensors 27 and 29 were purchased,
The current bending angle θ is detected using the following equation. This means for detecting the current bending angle θ is called a bending angle detecting means.

θ-O1 Moro 2-α The detected current bending angle θ and the target bending angle θ0 stored in advance in the NC device 31 are taken into the CPU 43, and Δθ-100-01 is arithmetic processed. 〇 is calculated for the corrected bending angle.

The means for determining this corrected bending angle Δθ is called bending angle Tσ correction means.

If the corrected bending angle △θ obtained by this bending angle correction means is equal to or greater than the allowable value, it is outputted to the NC device 31 or displayed on the display 35 so that it approaches the target bending angle 60, and the bending angle is Correction is performed by automatically operating the bending force using the pressure correction means.

If the corrected bending angle is less than or equal to the allowable value, the bending process ends.

The clamp displacement detection method will be explained. As shown in FIGS. 5 and 6, when the workpiece W is clamped by the clamp jig 3-23 of the workpiece clamper 25, the NC device 31 moves the tip of the workpiece W to the target position (Xo , Vo). At this time, the amount of movement is the position of the visual sensor 27, (Xo, Vo)
It is determined by the coordinate values of .

This means for determining the current tip position of the workpiece W is called a workpiece tip position detection means.

From the image of the tip position n of the workpiece W marked by the visual sensor 27, the target tip position of the workpiece W (XW, yw) is determined.
Find the deviation d (for the y-axis only). The means for determining this deviation (j) is called a workpiece position correction means. This deviation d is the amount of clamp deviation, and as position correction data, this deviation d is output to the NC device 31 or displayed on the display 35. Position correction is performed automatically or manually.

After performing position correction, as shown in Figure 7,
The bending process is performed at a distance MLF from the tip of the workpiece W.

Next, the entire operation of J3 in this embodiment will be explained based on the flowchart shown in FIG.

In FIG. 8, at J3, (2) clamp deviation detection processing is performed.

In other words, ■, the work clamper 25 is operated by the NC device 31.
The workpiece W is clamped by the clamp jaws 23 and moved to the deviation detection target position iQ as shown in FIG. ■,
A clamp deviation detection command is sent from the NC device 31 to the image processing device 33. (2) The image processing device 33 starts processing. (2) Capture an image using the visual sensor 27 and output it to the image processing device 33; (2) Measure 81 clamp misalignment;
Output to the device 31. [F], the NC device 31 is
is corrected and positioned at a predetermined bending position.

■ Bending processing is performed. That is, ◎: A bending angle detection command is sent from the NC device 31 to the image processing device 33. (2) The image processing device 33 starts the bending J process.

(2) The visual sensor 27 outputs a cross-sectional image of the workpiece W to the image processing device 33. (2) The angle θ1 is measured based on the image data.

(2) The visual sensor 29 outputs a cross-sectional image of the workpiece W to the image processing device 33, and (2) C1 angle θ based on the image @f-y
Perform 2 measurements. (2) Next, in the image processing device 33, θ-
Calculation processing of θ1+θ2−α is performed. (2) This calculated angle θ is output to the NC device 31, and the NC device 31 calculates the deviation Δθ between this angle θ and a pre-stored target bending angle θ0. ◎, Next, if this deviation is greater than the allowable value, adjust the pressurizing force.

Then, ■, repeat the steps from ◎ to ◎ above, Q,
When the deviation Δθ becomes less than or equal to the allowable value, the bending angle correction work is completed.

In this way, clamp displacement detection and correction, as well as bending angle detection and correction, can be performed automatically and easily. Therefore, highly accurate bending processing can be performed automatically.

J5, this invention is not limited to the embodiments described above, but can be implemented in other embodiments by making appropriate changes.

[Effects of the Invention J] As can be understood from the description of the embodiments below, according to the present invention, while the workpiece is being bent by the bending machine, the clamping displacement of the workpiece can be detected, By automatically performing correction, bending angle detection, and supplementary iF, high-precision bending processing can be performed automatically.

[Brief explanation of drawings]

FIG. 1 shows the main parts according to the present invention, and is a configuration control block diagram of an image processing device, FIG. 2 is a state diagram when a cross-section of a workpiece is imaged with a visual sensor, and FIG. FIG. 4 is an enlarged positive image of a cross section of the workpiece for which the bending angle is to be detected; FIGS. FIG. 8 illustrates the operation of this embodiment.
, FIG. 9, and FIG. 10 are explanatory diagrams of a state in which a visual sensor is installed to take an image of a cross section of a workpiece, and FIG. 11 is a perspective view of a swinging press according to an embodiment of the present invention.

Claims (2)

[Claims] (1) A bending angle correction device for a bending machine that bends a workpiece interposed between a punch and a die using both dies, and an appropriate number of imaging means for imaging the end face shape of the workpiece. , a bending angle detection means for detecting the current bending angle of the workpiece based on an image of the end face shape of the workpiece taken by the image means; a bending angle correction means for correcting the bending angle to a target bending angle; and a bending force correction means for automatically correcting the bending force based on the corrected bending angle obtained by the bending angle correction means. A bending angle correction device for a bending machine, characterized by comprising: (2) The claim (1) further includes a workpiece clamping means for clamping the workpiece, an imaging means for taking an image of the workpiece after being clamped and positioned by the workpiece clamping means, and an image of the workpiece taken by the imaging means. workpiece tip position detection means for detecting the current tip position of the workpiece based on the workpiece tip position; and position correction so that the current position of the workpiece detected by the workpiece tip position detection means becomes a preset target tip position of the workpiece. A bending angle correcting device for a bending machine, characterized in that it is equipped with a workpiece position correcting means.