JPH07265957A - Press brake - Google Patents

Abstract

PURPOSE:To provide a press brake capable of bending a plate-shaped work with high precision and in a short time. CONSTITUTION:In the bending of a work W, the temporary advancement position of a ram 14 is found from the working condition of the work to be received from a working condition input part 21 and the relationship between the spring back angle and the target bending angle of the work stored in a spring back data part 24, the ram 14 is driven to this temporary advancement position, and the bending angle of the work is detected by an angle measuring unit 18 at the position. Then, the final advancement position of the ram 14 is obtained from this detected bending angle and the relationship between the advancement of the ram 14 and the bending angle of the work stored in a bending angle - advancement data part 23, and the relationship between the spring back angle and the target bending angle of the work stored in the spring back data part 24, and the ram 14 is driven to this obtained final advancement position to complete the bending.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a press brake for bending a work by means of an upper die and a lower die which is arranged so as to face the upper die. More specifically, the bending angle of the work is controlled during the bending process. The present invention relates to a press brake which can be bent by a bending angle detecting means to perform highly accurate bending.

[0002]

2. Description of the Related Art Conventionally, in a press brake which performs V bending by pressing a plate-like work by an upper die (punch) and a lower die (die), the work material, sheet thickness, and die conditions. It is known that the NC device controls the driving amount of the upper die or the lower die based on data such as the above. In such a press brake, it is difficult to accurately control the amount of drive due to factors such as the plate thickness of the work and variations in material characteristic values.Therefore, the bending angle of the work is measured during the bending process. It has been proposed to improve the bending accuracy by feeding back the measurement result to the die pushing amount. In this case, the springback (return due to elasticity) angle of the work also changes depending on the work material, plate thickness, die conditions, etc., so it is necessary to detect this springback angle in-line.

From this point of view, various proposals have been made in the past for accurately calculating the final drive amount of the driving die. For example, in the one disclosed in Japanese Patent Application Laid-Open No. 1-228612, the springback amount required to obtain the final drive-in position of the driving die is automatically detected for each work, and the springback amount thus detected and the target bending amount are detected. The final drive-in position is calculated from the angle and the actual bending angle. Further, for example, in the one disclosed in Japanese Patent Laid-Open No. 3-71922, the work is bent to a temporary drive-in position and then unloading is performed, and the final drive-in position is calculated from the change in the pressing force at the time of unloading. Has been done.

[0004]

However, in each of the above-mentioned publications, it is necessary to control a complicated driving die, that is, a ram, in order to detect the springback angle. Therefore, there is a problem that productivity is lost.

The present invention has been made in order to solve the above problems, and an object thereof is to provide a press brake capable of highly accurately bending a plate-like work in a short time. To do.

[0006]

In view of the above-mentioned problems, the present inventor has found that the springback angle has little variation between lots, and if the springback angle is layered according to the material of the work and the plate thickness, the accuracy is improved. The inventors have found that they can be estimated well and have completed the present invention.

In short, the press brake according to the present invention is, as shown in the principle diagram of FIG. 1, a press for bending a work by an upper mold and a lower mold arranged so as to face the upper mold. In the brake, (a) a storage means 2 for storing the processing conditions of the work, the relationship of the springback angle to the target bending angle of the work, and the relationship of the driving amount of the driving die 1 to the bending angle of the work, (b) during the bending process Bending angle detecting means 3 for detecting the bending angle of the work, (c) Temporary movement of the driving die 1 from the relationship between the processing conditions of the work stored in the storage means 2 and the springback angle with respect to the target bending angle of the work. Is calculated, and the bending angle of the workpiece detected by the bending angle detection means 3 at the temporary driving position and the storage means. The calculation means 4 and (d) for calculating the final drive-in position of the drive mold 1 from the relationship of the springback angle to the target bend angle of the work and the relationship of the drive-in amount of the drive mold 1 to the bend angle of the work stored in ) A mold driving means 5 is provided for driving the driving mold 1 to the temporary driving position and then driving it to the final driving position.

In the present invention, further, a springback data updating process for updating the data relating to the relationship between the target bending angle of the work and the springback angle in accordance with the actually measured bending angle data detected by the bending angle detecting means 3. Means 6 are preferably provided.

Further, the data relating to the relationship of the driving amount of the driving die 1 with respect to the bending angle of the work is updated according to the actual measurement data of the bending angle detected by the bending angle detecting means 3 to update the bending angle and the driving amount data. It is preferable to provide processing means 7. In this case, update data relating to the relationship between the bending angle of the work and the driving amount of the driving mold 1 is
It can be obtained by directly calculating an approximate expression from the actual measurement data of the bending angle detected by the bending angle detecting means 3, or from the actual measurement data of the bending angle detected by the bending angle detecting means 3 in advance. It can also be obtained by a correction calculation for the registered approximate expression registered in the storage means 2.

Further, the provisional drive-in position of the drive mold 1 is set to a position where the drive mold 1 comes into contact with the work, and the mold drive means 5 can be manually driven from this contact position to the final drive-in position. You can

Further, after the bending process is completed, the bending accuracy is confirmed by detecting the bending angle of the work by the bending angle detecting means 3, and the final drive-in position of the driving die 1 is corrected according to the confirmed bending accuracy. Preferably.

[0012]

When bending the work, the temporary of the driving mold 1 of the upper mold or the lower mold is determined from the relationship between the working condition stored in the storage means 2 and the springback angle with respect to the target bending angle of the work. Is calculated, and the driving mold 1 is driven by the mold driving means 5 to the temporary driving position, and the bending angle of the work is detected by the bending angle detecting means 3 at that position. Next, based on the detected bending angle and the relationship of the driving amount of the driving mold 1 with respect to the bending angle of the workpiece stored in advance in the storage unit 2, the driving amount of the driving mold 1 at the temporary driving position is determined. The final drive-in position of the drive mold 1 is determined from the relationship between the drive amount of the drive die 1 with respect to the bending angle of the work and the relationship of the springback angle with respect to the target bend angle of the work. Then, the driving die 1 is driven to the obtained final drive-in position, and the bending process is completed. In this way, it is possible to perform highly accurate bending processing in a short time by detecting the angle once, without the need for complicated control of the driving mold 1 and repeated detection of the bending angle.

In the present invention, the bending angle detecting means 3 detects the data relating to the relation of the springback angle to the target bending angle of the work and the data relating to the relation of the driving amount of the driving die 1 to the bending angle of the work. If it can be updated according to the actual measurement data of the bending angle, the bending angle accuracy can be further improved, and various materials can be flexibly dealt with.

In this case, update data relating to the relationship between the bending angle of the work and the driving amount of the driving die 1 is registered in advance in the storage means 2 from the actual measurement data of the bending angle detected by the bending angle detection means 3. If the calculation is performed by the correction calculation for the registered approximation formula, the updated data can be easily calculated by using the registered approximation formula registered in advance.

Further, the provisional drive-in position of the drive mold 1 is set to a position where the drive mold 1 comes into contact with the workpiece, and the mold drive means 5 can be manually driven from this contact position to the final drive-in position. If a teaching mode is provided,
Since the operator can perform the bending while checking the bending state, it is possible to perform the bending of the special material, and the flexibility of the system can be enhanced.

Further, after the bending process is completed, the bending accuracy is confirmed by detecting the bending angle of the work by the bending angle detecting means 3, and the final drive-in position of the driving die 1 is corrected according to the confirmed bending accuracy. By doing so, the more accurate final drive-in position value obtained by such correction can be used for the next bending process, and detection of the bending angle from the next time can be omitted.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, specific embodiments of the press brake according to the present invention will be described with reference to the drawings.

FIG. 2 shows a system configuration diagram of an embodiment of the present invention. In the press brake 11 of the present embodiment, a lower die (die) supported by the gantry 12
13 and an upper die (punch) 15 that is attached to a lower portion of a ram 14 that is provided above the lower die 13 and that can be lifted and lowered above the lower die 13. The lower die 13 and the upper die 15 are provided. A work W made of a metal plate is inserted between the lower mold 13 and the lower mold 13 and the ram 14 is lowered to place the work W between the lower mold 13 and the upper mold 15. The work W is bent by being pinched.

At the front part (man side) of the mount 12,
An angle measuring unit 18 including a slit-shaped light source 16 for projecting a linear projection image on the bent outer surface of the work W and a CCD camera 17 for capturing the linear projection image by the light source 16 is attached. The bending angle of the work W is measured by the measuring unit 18. The angle measuring unit 18 may be provided at the rear part (machine side) of the gantry 12 instead of at the front part of the gantry 12, or may be provided at both the front part and the rear part of the gantry 12.

The image picked up by the CCD camera 17 is displayed on a monitor television (not shown) and is processed by the bending angle calculation section 19 as image data. Then, the bending angle of the work W is calculated by the calculation in the bending angle calculation unit 19, and the calculation result is input to the NC device 20.

In the NC device 20, work information (material, bending line length, bending angle, etc.), die information (die height, V)
Groove width, V angle, punch R, etc.), machining condition input section 21 for inputting various data such as machine information (rigidity, speed specifications, stroke specifications, etc.) and machining conditions input from this processing condition input section 21. Accordingly, the measurement / pass / fail condition setting is performed to set various conditions such as angle measurement position in bending, measurement process number and tolerance data, sampling conditions (number of times, angle) for updating the database, and bending angle pass / fail judgment conditions. The part 22 and the bending angle to the driving amount data part 23 in which the data relating to the amount of the ram 14 pushing into the bending angle is registered, and the spring in which the data relating to the relationship of the springback angle to the target bending angle is registered. When the temporary drive-in position (lower limit position) of the ram 14 is calculated based on the data from the back data unit 24 and the processing condition input unit 21 At the same time, the final drive-in position of the ram 14 is calculated based on the data from the bending angle to the drive-in amount data unit 23 and the springback data unit 24, the data from the processing condition input unit 21 and the data from the bend angle calculation unit 19. A drive-in position calculation unit 25 that outputs a drive signal to the ram 14 based on these calculation results, a pass / fail determination unit 26 that determines the bending accuracy of the work that has been subjected to bending processing based on the data from the bending angle calculation unit 19, and this pass / fail determination. A drive-in position changing unit 27 that changes the drive-in position of the ram 14 based on a signal from the unit 26 is further provided, and the data from the bend angle calculating unit 19 is temporarily stored to newly set the bend angle to the drive-in amount data unit 23. Bending angle to set data or update data, set calculation form and calculate coefficient The data update processing unit 28 and the springback data for temporarily storing the data from the bending angle calculation unit 19 and registering new data or update data in the springback data unit 24, and setting the calculation form and calculating the coefficient. The update processing part 29 is provided.

Thus, when bending the work W, first, the work conditions such as work information, mold information, machine information, etc. input from the work condition input section 21 and the work W registered in the springback data section 24 are processed. Based on the relationship between the target bending angle and the springback angle, the drive-in position calculation unit 25 determines the temporary drive-in position of the ram 14, and the ram 14 is driven to the temporary drive-in position and the upper die 15 is lowered. Next, the bending angle of the work W is measured by the angle measuring unit 18 at this temporary driving-in position, and this bending angle is calculated by the bending angle calculation unit 19
Is calculated in. After that, the driving amount of the ram 14 at the temporary driving position is obtained from the calculated bending angle and the relationship between the bending angle and the driving amount of the ram 14 with respect to the bending angle registered in the driving amount data section 23. Further, the final drive-in position of the ram 14 is obtained from the relationship of the amount of the ram 14 driven in with respect to the bending angle and the relationship of the springback angle with respect to the target bending angle of the workpiece W registered in the springback data section 24. Then, the ram 14 is driven to the obtained final drive-in position and bending is performed.

After the bending process is performed in this way, in this embodiment, the ram 14 is slightly lifted and the bending angle is measured again to check the accuracy, and the final ram 14 driving amount is automatically corrected. It is made possible. Then, by using the value of the final drive-in amount with satisfactory accuracy obtained by such automatic correction for the next bending process, it is possible to omit the measurement of the bending angle from the second time and thereafter. There is.

In the bending process of the present embodiment, a so-called teaching mode in which the upper die 15 is brought into contact with the work W and the work W is pressed and held to manually lower the ram 14 to perform the bending work. Are available for selection.
By providing the teaching mode in this way, the operator can perform bending while confirming the bending state, bending of a special material can be performed, and flexibility of the system can be enhanced.

Further, in this embodiment, in order to improve the bending accuracy, the data of the driving amount of the ram 14 with respect to the bending angle registered in the bending angle to the driving amount data unit 23 is supplied from the bending angle calculation unit 19. The bending angle to the drive-in amount data update processing unit 28 according to the measured data of the bending angle.
The data registered in the springback data unit 24 can also be updated by the springback data update processing unit 29 in accordance with the actual measurement data of the bending angle from the bending angle calculation unit 19. ing. As a result, the bending angle accuracy can be further improved, and various materials can be flexibly dealt with.

Next, the bending process of this embodiment will be described with reference to the flow chart shown in FIG.

S1 and S2: It is judged whether or not the bending angle measurement mode is set (S1), and when not in the measurement mode, bending is executed in the normal mode (S2) and the flow is ended. On the other hand, when it is in the measurement mode, the process proceeds to step S3. Whether or not the bending is performed in the bending angle measurement mode is set by an operator using an external switch. S3 to S6: Work information (material, bending line length, bending angle, etc.), mold information (mold height, V) from the processing condition input unit 21.
Enter machining conditions such as groove width, V angle, punch R, etc., machine information (rigidity, speed specifications, stroke specifications, etc.) (S
3) Next, the longitudinal position and setting state of the angle measuring unit 18, which is the condition for measuring the bending angle, are set (S4). Then, the provisional target lower limit position of the ram 14 is determined from the relationship between the processing condition and the springback angle of the workpiece W registered in the springback data section 24 (S5), and the NC device 20 is activated ( S6).

S7: It is determined whether or not the teaching mode is set. When the teaching mode is not set, the process proceeds to step S8, and when the teaching mode is set, the process proceeds to step S13. S8 to S10: Since the teaching mode is not selected, the work W is set between the upper mold 15 and the lower mold 13 (S8), and the upper mold 15 is lowered to the temporary target lower limit position. Then, the bending is performed (S9), the angle is measured by the angle measuring unit 18 at the temporary target lower limit position, and the measurement result is displayed (S10).

S11 to S12: measurement angle <target bending angle-
Whether or not the springback angle + constant (where the constant is a value such as a tolerance) is satisfied, in other words, the ram 14
Determines whether or not has reached the final lower limit (S1
1). Then, as a result of this determination, when the final lower limit value is not reached, the relationship between the measured bending angle and the bending angle to the bending angle registered in the driving-in amount data section 23, and the spring-back data section The final lowering position (final lower limit value) of the ram 14 is obtained from the relationship between the springback angle and the target bending angle of the work W registered in No. 24, and the target lower limit value is changed (S12). Return to continue bending. On the other hand, when the ram 14 has reached the final lower limit value, the process proceeds to step S21.

S13 to S18: Since the teaching mode is selected, the target lower limit position, in other words, the position where the tip of the upper die 15 touches the work W is set from the above processing conditions (S13), and then described later. In order to display the limit value during the manual bending process of the ram 14, the final lower limit position of the ram 14 and the springback are determined from the relationship between the processing condition and the springback angle with respect to the target bending angle of the workpiece W registered in the springback data section 24. The reference value of the angle is displayed (S14). Thereafter, the work W is set between the upper mold 15 and the lower mold 13 (S15), and the upper mold 15 is lowered to the target lower limit position to move the work W to the upper mold 15 and the lower mold 13. The pressure is maintained during the period (S16). Then, in this state (the pressure switch is turned on), the pulse generator is manually rotated to lower the ram 14 to bend the workpiece W (S17), and the angle is measured and the measured value is displayed. Yes (S18).

S19 to S20: Measurement angle <target bending angle-
It is determined whether or not the springback angle + constant is established (S19), and when not established (the ram 14 has not reached the final lower limit value), a reference value for the final drive-in position (final lower limit value) of the ram 14 Is displayed and requested (S20),
Thereafter, the process returns to step S17 to continue the bending process, while when the ram 14 has reached the final lower limit value, the process proceeds to step S21.

S21 to S23: Raise the ram 14 (S
21) Then, it is determined whether or not to confirm the bending accuracy (S22). Then, when the accuracy is not confirmed, the flow is ended, and when the accuracy is confirmed, the measured value of the bending angle is displayed (S23). In this case, in order to prevent the work W from falling and being unable to measure the angle due to the rise of the ram 14, it is desirable to perform the angle measurement while the work W is lightly clamped.

S24 to S26: Whether or not the measured angle is within the allowable range (S24), and if it is within the allowable range, the final lower limit value is automatically corrected (S25) and the flow is ended. On the other hand, if it is not within the allowable range, it means that the bending process has failed. Therefore, it is determined whether or not the forced lower limit correction is performed (S26). If the correction is performed, the process proceeds to step S25. If the correction is not performed, Ends the flow.

Next, the bending angle-the driving amount data update processing unit 28 detects the bending angle from the bending angle detection data.
A method for obtaining the relationship of the drive-in amount and a method for estimating the final drive-in amount of the ram 14 from the calculated relationship will be described. The method for obtaining the relationship between the bending angle and the amount of drive-in can be divided into a new method for directly obtaining it and a method for correcting an already registered equation.

(1) Method for directly obtaining the relationship between the bending angle and the driving amount based on the angle measurement data In this method, angle measurement is first performed several times during bending of a work of a predetermined material, Bending angle-follow-up amount data as shown in FIG. 4 is obtained. Then, based on the measurement data thus obtained,
An appropriate arithmetic expression format is selected from among several kinds of arithmetic expression formats prepared in advance, and the relational arithmetic expression (approximate arithmetic expression) between the bending angle and the driving amount is obtained by the selected arithmetic expression format. To be Table 1 shows an example of a registration table for this approximate arithmetic expression. In the example of Table 1, the coefficients X, Y, and Z of the arithmetic expression format: D _p = XA ² + YA + Z are obtained from the measurement data, and the relationship between the bending angle and the driving amount is quantified.

[0036]

[Table 1]

The relationship between the bending angle and the driving amount thus obtained and the relationship of the springback angle with respect to the previously registered target bending angle (springback table)
From the above, the final lower limit value of the ram 14 is obtained as follows (see the flow chart shown in FIG. 5 and the graph shown in FIG. 6).

First, a temporary lower limit value D _pp is obtained from the processing conditions and the like (T1), and bending is performed up to this temporary lower limit value D _pp (T2). Next, the angle measurement is performed at the temporary lower limit value D _pp to obtain the measurement angle FA (T3), and the bending angle corresponding to the obtained measurement angle FA-the drive amount D in the drive amount curve (FIG. 6). ₀ is calculated (T4). Next, referring to the springback table, the amount D ₁ of the bending angle-the amount of drive-in at the point WA-SB (target bending angle-springback angle) in the curve of the amount of drive-in is calculated (T5), and finally,
The final drive amount (final lower limit value) D _pl is _calculated by the following equation (T6). D _pl = D _pp − (D ₀ −D ₁ )

(2) Method for correcting the already registered relationship between the bending angle and the pushing amount In this method, the angle is measured several times during the bending process in the same manner as in (1), and the bending angle is the pushing amount. After the data is obtained, an appropriate one arithmetic expression format is selected, and the relational arithmetic expression (approximate arithmetic expression) of the correction value of the driving amount with respect to the bending angle is obtained by this selected arithmetic expression format. This approximate calculation formula shows a correction formula for the calculation formula already registered in the NC device.
Table 2 shows an example of this correction formula registration table. In the example of Table 2, the coefficients l, m, and n of the arithmetic expression format: C = 1a ² + mA + n are obtained from the measurement data, and the relationship between the bending angle and the correction value of the driving amount is quantified. Note that FIG. 7 shows the relationship between the conventional calculated value (shown by the solid line) of the NC device and the calculated value based on the angle measurement, and FIG. 8 shows the relationship between the correction value and the bending angle. It is shown.

[0040]

[Table 2]

In the case of this method, the final lower limit value of the ram 14 is obtained as follows (see the graph shown in FIG. 9).

[0042] First, truly running bent to the lower limit value D _pp provisional performs angle measurement seeking measured angle FA at the lower limit D _pp This temporary, corresponding to the sought measurement angle FA The driving amount D _{0 of} is calculated by the following equation. D ₀ = d ₀ + c ₀ d ₀ : Calculation amount value of the current NC at the measurement angle point c ₀ : Correction amount at the measurement angle point Next, referring to the springback table, the bending angle ~
The true drive-in amount D ₁ at the WA-SB (target bending angle-spring back angle) point in the drive-in amount curve is calculated by the following formula. D ₁ = d ₁ + c ₁ d ₁ : Current NC calculation drive-in amount value at WA-SB point c ₁ : Correction amount at WA-SB point Finally, the final drive-in amount (final lower limit value) D _{pl according} to the following formula
Ask for. D _pl = D _pp − (D ₀ −D ₁ ) = D _pp − (d ₀ + c ₀ −d ₁ −c ₁ ).

Next, the processing flow for updating the bending angle to the drive-in amount data will be described with reference to the flowchart of FIG. A sample work is used for this updating process.

U1 to U4: Set machining conditions such as work information, mold information, machine information and product information (U1), and set measurement conditions such as a measurement angle for measuring a bending angle and the number of measurements ( U2) The lower limit value of the first bending is set (U3). Then, the work W is set between the upper mold 15 and the lower mold 13 (U4). U5 to U8: Bending is performed (U5), the angle is measured, and the data of the measurement result is stored (U6). Then, it is determined whether or not the number of measurements reaches the set number (U
7) If not reached, the value is changed to the next lower limit (U8) and the process returns to step U5. If the set number of times is reached, the process proceeds to step U9.

U9: Select an appropriate arithmetic expression format from the arithmetic expression formats relating to the relationship between the bending angle and the driving amount. U10 to U13: It is determined whether or not the relationship between the bending angle and the pushing amount is directly obtained (U10), and when it is directly obtained, the coefficient of the relational expression of the bending angle and the pushing amount is obtained and quantified (U11). When the calculation value is to be obtained by correction, the coefficient of the relational expression of the correction value of the bending angle to the correction amount is obtained and quantified (U12). Then, the obtained data is registered in a table and made into a database (U13).

Next, the flow of updating the springback data will be described with reference to the flowchart of FIG. A sample work is also used in this updating process.

V1: It is determined whether or not there is a load monitor for detecting the unloading state of the work W. If there is no load monitor, the processes from step V2 to step V13 are performed. If there is a load monitor, the process starts from step V14. The processing up to step V25 is performed. V2 to V4: Input processing conditions such as work information, mold information, and machine information from the processing condition input unit 21 (V2), and then set the longitudinal position and setting state of the angle measuring unit 18, which is the bending angle measuring condition. Set (V3). Then, the lower limit position of the ram 14 relating to the first bending angle of the work W is obtained from the processing conditions and the like (V4).

V5 to V10: The work W is set between the upper die 15 and the lower die 13 (V5), and the upper die 15 is lowered to the lower limit position for bending (V6). The angle is measured by the angle measuring unit 18 at the position and the measurement result is displayed (V7). Then ram 14
Is raised to a predetermined position (V8), the angle is measured again at the raised position, and the measurement result is displayed (V
9). Then, the springback angle for the target bending angle obtained from the measurement results of these bending angles is temporarily stored (V10). V11: It is determined whether or not the number of measurements reaches the set number,
If not reached, the process returns to step V5, and if reached, the process proceeds to step V12.

V12: It is judged whether or not the measurement for all the target bending angles is completed. If not completed, the process proceeds to step V13, and if completed, the process proceeds to step V26. V13: Since the measurement of all angles has not been completed, the lower limit reference value of the ram 14 for the next target bending angle is calculated and the process returns to step V5.

V14 to V19: The same processing as steps V2 to V7 in the case without the load monitor described above is performed. V20 to V22: The ram 14 is raised until the load detected by the load monitor reaches a predetermined value (V20), the angle is measured again at this raised position, and the measurement result is displayed (V21). Then, the springback angle for the target bending angle obtained from the measurement results of these bending angles is temporarily stored (V22).

V23: It is determined whether or not the measurement for all the target bending angles is completed. If not completed, the process proceeds to step V24, and if completed, the process proceeds to step V25. V24: Since the measurement of all angles has not been completed, the lower limit value of the ram 14 for the next target bending angle is calculated, and the process returns to step V18. V25: It is determined whether or not the number of measurements reaches the set number,
If not reached, the process returns to step V16, and if reached, the process proceeds to step V26.

V26 to V27: The coefficient of the approximate arithmetic expression for calculating the springback angle is obtained (V26), and the obtained data is registered in a table and made into a database (V27).

If there is no load monitor as described above, data relating to one target bending angle can be obtained from one sample work piece in the processing from step V5 to step V11. If there is a load monitor, from step V17. In the processing up to step V25, data relating to a plurality of target bending angles can be obtained with one sample work. Note that steps V17 to V2 when there is a load monitor
The processes up to 5 can be automatically executed.

Table 3 shows an example of a table for registering the springback angle thus obtained. In this way, the springback angle depends on the material, plate thickness, die V
A predetermined value is registered and updated for each width and punch R and for each target bending angle.

[0055]

[Table 3]

[0056]

As described above, according to the present invention, the bending angle of the work is detected at the temporary driving position,
From the relationship between the detected bending angle, the springback angle with respect to the target bending angle of the workpiece stored in the storage unit 2 and the relationship between the bending amount of the driving die 1 with respect to the bending angle of the workpiece, the final driving die 1 is obtained. Since the drive-in position is calculated, it is not necessary to perform complicated control of the driving die 1 or to detect the bending angle many times, and highly accurate bending can be performed in a short time by detecting the angle once. Therefore, productivity can be improved.

In the present invention, the bending angle detecting means 3 detects data relating to the relationship of the springback angle to the target bending angle of the work and data relating to the relationship of the driving amount of the driving die 1 to the bending angle of the work. If it can be updated according to the actual measurement data of the bending angle, it is possible to further improve the bending angle accuracy and flexibly deal with various materials.

The so-called tentative drive-in position of the drive mold 1 is set to a position where the drive mold 1 comes into contact with the work, and the mold drive means 5 can be manually driven from this contact position to the final drive-in position. If a teaching mode is provided,
Since the operator can perform bending while checking the bending state, it is possible to perform bending of a special material, which is suitable for one-time bending of an unknown work piece, and system flexibility Can be increased.

After the bending process is completed, the bending accuracy is confirmed by detecting the bending angle of the work by the bending angle detecting means 3, and the final driving-in position of the driving die 1 is corrected according to the confirmed bending accuracy. By doing so, the more accurate final drive-in position value obtained by such correction can be used for the next bending process, and detection of the bending angle from the next time can be omitted.

[Brief description of drawings]

FIG. 1 is a diagram showing the principle of the invention of a press brake according to the present invention.

FIG. 2 is a system configuration diagram of an embodiment of the present invention.

FIG. 3 is a flowchart showing a bending process of this embodiment.

FIG. 4 is a graph showing the relationship between the bending angle of a work and the amount of ram driven in.

FIG. 5 is a flowchart for calculating the final lower limit value of the ram in the method of directly obtaining the relationship between the bending angle and the driving amount.

FIG. 6 is a graph illustrating a formula for calculating a final lower limit value of a ram in a method of directly obtaining a relationship between a bending angle and a driving amount.

FIG. 7 is a graph showing a relationship between a measured value and a conventional calculated value in a method of obtaining a relationship between a bending angle and a driving amount by a correction calculation.

FIG. 8 is a graph showing a relationship between a bending angle and a correction value in a method of obtaining a relationship between a bending angle and a driving amount by a correction calculation.

FIG. 9 is a graph illustrating a calculation formula of a final lower limit value of a ram in a method of obtaining a relationship between a bending angle and a driving amount by a correction calculation.

FIG. 10 is a flowchart showing a flow of processing for updating bending angle-follow-up amount data.

FIG. 11 is a flowchart showing a flow of update processing of springback data.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Driving die 2 Storage means 3 Bending angle detecting means 4 Computing means 5 Mold driving means 6 Springback data updating processing means 7 Bending angle / pushing amount data updating processing means 11 Press brake 13 Lower mold 14 Ram 15 Upper mold 16 light source 17 CCD camera 18 angle measurement unit 19 bending angle calculation unit 20 NC device 21 processing condition input unit 22 measurement / acceptance condition setting unit 23 bending angle-drive amount data unit 24 springback data unit 25 drive-in position calculation unit 26 pass / fail judgment Part 27 Drive-in position change unit 28 Bending angle-drive-in amount data update processing unit 29 Springback data update processing unit

Claims (7)

[Claims] 1. In a press brake for bending a work by an upper die and a lower die arranged to face the upper die, (a) a working condition of the work and a springback angle with respect to a target bending angle of the work. Relationship, and storage means for storing the relationship of the driving die driving amount with respect to the bending angle of the work, (b) bending angle detection means for detecting the bending angle of the work during the bending process, (c) stored in the storage means. The temporary driving-in position of the driving die is calculated from the relationship between the working condition of the workpiece and the springback angle with respect to the target bending angle of the workpiece, and the workpiece is detected by the bending-angle detecting means at the temporary driving-in position. Relationship between bending angle, springback angle with respect to target bending angle of work stored in storage means, and bending angle of work Calculation means for calculating the final drive-in position of the drive mold from the relationship of the drive-in drive amount with respect to the degree, and (d) the mold drive for driving the drive mold to the temporary drive-in position and then to the final drive-in position. A press brake comprising means. 2. Springback data update processing means for updating data relating to the relationship of the springback angle with respect to the target bending angle of the work according to the actual measurement data of the bending angle detected by the bending angle detecting means is provided. The press brake according to claim 1. 3. The bending angle / pushing amount data update for updating the data relating to the relationship between the bending angle of the work and the driving amount of the driving die according to the actual measurement data of the bending angle detected by the bending angle detecting means. The press brake according to claim 1 or 2, further comprising processing means. 4. The bending angle / pushing amount data update processing means uses update data relating to the relationship between the bending angle of the workpiece and the driving amount of the driving die from the actual measurement data of the bending angle detected by the bending angle detecting means. The press brake according to claim 3, wherein the press brake is obtained by directly calculating an approximate expression. 5. The bending angle / push-in amount data updating processing means updates update data relating to the relationship between the bending angle of the work and the pushing-in amount of the driving die from the measured bending angle data detected by the bending angle detecting means. The press brake according to claim 3, wherein the press brake is obtained by a correction calculation with respect to a registration approximation formula registered in advance in the storage means. 6. A temporary drive-in position of the drive mold is a position where the drive mold contacts the work, and the mold drive means can be manually driven from the contact position to the final drive-in position. The press brake according to claim 1, wherein: 7. The bending accuracy is confirmed by detecting the bending angle of the work by the bending angle detecting means after the bending process is completed, and the final drive-in position of the driving die is corrected according to the confirmed bending accuracy. The press brake according to claim 1, which is provided.