Bending method and bending system

Abstract

To achieve stabilization of quality of a finished article while reducing burden of accuracy confirmation work on an operator.SOLUTION: A bending method comprises: an acquisition process in which a reference value of an origin position of a punch with respect to a die is acquired for each finished article before start-up of work-piece bending by a bending machine having the punch and the die; a storage process in which the acquired reference value is stored by linking the same to each finished article; a readout process in which the reference value linked to the finished article for which bending is executed is read out; a measurement process in which a measurement value of the origin position is acquired after the start-up of work-piece bending; a calculation process in which on the basis of the measured measurement value, the reference value or an amount of change over time from the previous measurement value is calculated as a push-in amount of the punch to the die and a correction value for change over time of the origin position of the punch; and a re-setting process in which during automatic operation of work-piece bending, the push-in amount or the origin position is re-set for each prescribed trigger condition by use of the correction value for change over time.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a bending method and a bending system. [Background technology]

[0002] There is known a bending machine that, when bending a workpiece, determines an approximation equation for the bending load based on the initial bending load and the relative movement position of the punch with respect to the die (see Patent Document 1). In this bending machine, the approximation equation is determined each time bending is performed, after a predetermined number of bending operations, or after an arbitrary number of bending operations, etc., to correct changes in the bending angle caused by displacement of the frame due to changes in the bending machine over time. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-88183 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the bending machine disclosed in the above Patent Document 1, even when bending a plurality of different types of workpieces continuously over a long period of time, the machine operation must be stopped every time a correction is made, and the operator must also periodically check the bending accuracy after switching between workpieces, etc. For this reason, there is a limit to stabilizing the quality of the workpieces while reducing the burden of the accuracy check work.

[0005] One aspect of the present invention is a bending method and bending system that can stabilize the quality of a processed product while reducing the burden of accuracy checking work on an operator. [Means for solving the problem]

[0006] A bending method according to one embodiment of the present invention includes an acquisition step of acquiring a reference value of an origin position of the punch relative to the die for each workpiece before starting bending of the workpiece using a bending machine having a punch and a die; a storage step of linking and storing the acquired reference value for each workpiece; a reading step of reading out the reference value linked to the workpiece for which bending is to be performed; a measurement step of acquiring a measurement value of the origin position after starting bending of the workpiece; a calculation step of calculating, based on the measured measurement value, the reference value or a change over time from the previous measurement value as a push-in amount of the punch relative to the die or a correction value for change over time of the origin position of the punch; and a resetting step of resetting the push-in amount or the origin position for each specified trigger condition using the correction value for change over time during automatic operation of bending the workpiece.

[0007] According to a bending method according to one aspect of the present invention, before the bending machine starts bending a workpiece, a reference value of the punch origin position relative to the die for each workpiece is obtained, and this reference value is associated with each workpiece and stored. Then, the reference value associated with the workpiece to be bent is read out, and after the bending operation starts, a measurement value of the origin position is obtained, and based on the measurement value, the amount of change over time from the reference value or the previous measurement value is calculated as a correction value for the amount of push-in of the punch relative to the die or the origin position of the punch. Using this correction value for the change over time, the amount of push-in or the origin position is reset for each predetermined trigger condition during automatic operation of the bending operation. This reduces the burden on the operator in checking the accuracy, while stabilizing the quality of the workpiece. Effect of the Invention

[0008] According to one aspect of the present invention, it is possible to stabilize the quality of processed products while reducing the burden on the operator of checking accuracy. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is an explanatory diagram showing a basic configuration of a bending system for performing a bending method according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is an explanatory diagram showing a schematic overall configuration of the bending system. [Diagram 3] FIG. 3 is an explanatory diagram showing an outline of a general die used in a bending machine of a bending system. [Figure 4] FIG. 4 is a block diagram showing a schematic internal configuration of a control device of the bending system. [Diagram 5] FIG. 5 is a diagram for explaining a linking table between a processed product and a reference value stored in the storage unit of the control device. [Figure 6] FIG. 6 is a flowchart showing an outline of the processing procedure of the bending method executed by the bending system. [Figure 7] FIG. 7 is an explanatory diagram showing an overview of a general die used in a bending machine of a bending system according to a second embodiment of the present invention. [Figure 8] FIG. 8 is a flowchart showing an outline of a processing procedure of a bending method according to the third embodiment of the present invention. [Figure 9] FIG. 9 is a flowchart showing an outline of a processing procedure of a bending method according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, a bending method and a bending system according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. However, the following embodiments do not limit the invention according to each claim, and not all combinations of features described in the embodiments are necessarily essential to the solution of the invention. In addition, in the following embodiments, the scale and dimensions of each component may be exaggerated, and some components may be omitted.

[0011] [First embodiment] Fig. 1 is an explanatory diagram showing a basic configuration of a bending system for performing a bending method according to a first embodiment of the present invention. Fig. 2 is an explanatory diagram showing a schematic overall configuration of the bending system. Fig. 3 is an explanatory diagram showing an overview of a general die used in a bending machine of the bending system. Fig. 4 is a block diagram showing a schematic internal configuration of a control device of the bending system.

[0012] As shown in FIG. 1, the bending system 1 according to the first embodiment includes a bending machine 10 having a punch P and a die D, and a control device 30 that controls the bending machine 10 to perform bending. The control device 30 includes an acquisition unit 2 that acquires a reference value of the origin position of the punch P relative to the die D for each workpiece before the bending machine 10 starts bending the workpiece, a storage unit 32 that associates the acquired reference value with each workpiece and stores it, a readout unit 4 that reads out the reference value associated with the workpiece to be bent, a measurement unit 5 that acquires a measurement value of the origin position after the workpiece bending operation starts, a calculation unit 6 that calculates the reference value or the amount of change over time from the previous measurement value based on the measured measurement value as a push-in amount of the punch P relative to the die D or a correction value for the change over time of the origin position of the punch P, and a reset unit 7 that resets the push-in amount or the origin position for each predetermined trigger condition using the correction value for the change over time during automatic operation of the bending of the workpiece. In the first embodiment, the control device 30 includes, for example, an ON / OFF setting unit 9 that sets ON / OFF of execution of resetting in the resetting unit 7. The reference value is obtained for each processed product obtained by bending a workpiece, and is obtained when a predetermined pressure is reached by meshing the punch P and the die D.

[0013] 2, the bending system 1 includes an automatic robot 20 that is a manipulator that positions a workpiece relative to a punch P and a die D of a bending machine 10 such as a press brake, but is not limited to this. In a configuration including the automatic robot 20, a control device 30 controls the bending machine 10 and the automatic robot 20 to perform bending of the workpiece.

[0014] The control device 30 is configured with a general-purpose NC (numerical control) device, a workstation, a personal computer, or the like, and is configured to be able to communicate data with the bending machine 10 that actually bends the workpiece. The basic structures of the bending machine 10 and the automatic robot 20 are known, so only an outline will be described here. In the following description, the "X-axis direction" refers to the left-right direction when facing the front of the bending machine 10, the "Y-axis direction" refers to the depth direction in this case, and the "Z-axis direction" refers to the up-down direction in this case.

[0015] First, the bending machine 10 of the bending system 1 will be described. As shown in Fig. 2, the bending machine 10 has an upper table 11 and a lower table 12 at the center of the front. The upper table 11 and the lower table 12 are aligned in the vertical direction (Z-axis direction) so that one surface in the depth direction (Y-axis direction), for example, the outer plate surface, faces the front. The bending machine 10 also has support parts 13 arranged on the left and right sides to support the upper table 11 and the lower table 12.

[0016] The bending machine 10 further includes a drive mechanism 16. The drive mechanism 16 is configured to, for example, reciprocate the upper table 11 in the up-down direction relative to the lower table 12. The bending machine 10 also includes a position detection sensor 17 (see FIG. 4) that detects the movement position of the upper table 11 when it is moved by the drive mechanism 16.

[0017] Here, the upper table 11 and the lower table 12 are made of plate-like members such as metal. The upper table 11 has a plurality of upper die holders 14 at its lower part for holding an upper die such as a punch P. The lower table 12 has a lower die holder 15 at its upper part for holding a lower die such as a die D. In this embodiment, each support part 13 is formed, for example, by a plate-like side frame formed in a substantially U-shape when viewed from the side. However, each support part 13 is not limited to this and may be formed, for example, by a rod-shaped tie bar or the like.

[0018] The driving mechanism 16 is, for example, a hydraulic cylinder that serves as a driving source for the upper table 11. The driving mechanism 16 is attached to the upper part of each support part 13. Each driving mechanism 16 is configured to reciprocate (move up and down) the upper table 11 relatively in the up and down direction with respect to the lower table 12. Note that each driving mechanism 16 may use other driving means such as a servo motor instead of a hydraulic cylinder.

[0019] 4, the position detection sensor 17 detects the relative movement position of the punch P with respect to the die D when the upper table 11 is moved by the drive mechanism 16. This position detection sensor 17 is made up of, for example, an encoder or a linear scale, and is well known, so a detailed description of it will be omitted here.

[0020] The position detection sensor 17 can detect the pushing amount (movement stroke amount) (mm) that represents the blade distance on the D axis of the die by the punch P and the die D. The blade distance means, for example, the distance between the tip (lower end) of the punch P and the upper surface (opening end) of the die D, or the distance between the tip of the punch P and the bottom end of the die D, and may be defined as the D value.

[0021] In this embodiment, the push-in amount is defined as follows. That is, as shown in FIG. 3, for example, the position when the punch P and the die D are engaged with each other without a workpiece is defined as the reference position (0 mm) of the die. Then, the position of the tip (lower end) of the punch P at a predetermined position in the direction in which the punch P moves away from this reference position is defined as the stroke start (SS) position. The push-in amount represents the distance from the reference position to the SS position (so-called inter-blade distance) in this case. Note that the die used has a total length in the left-right direction of, for example, 35 mm or more. If the total length is less than 35 mm, there is a possibility that the die will not be able to withstand a predetermined load, which will be described later, when it is applied.

[0022] In the first embodiment, the reference value and the measured value are acquired based on the D-axis position when a predetermined load is applied to the punch P and the die D, as described in detail below. That is, the control device 30 reads the D-axis value when a predetermined load F (e.g., 10 kN ≈ 1000 kgf) is applied at this reference position as the reference value (UT0) or the measured value (UT1 to UTn) of the origin position of the punch P.

[0023] Then, based on these read values, the amount of change over time of the entire mechanical system including the die and the drive mechanism 16 is calculated as a correction value for change over time (ΔUT). This correction value for change over time (ΔUT) calculated in this manner is used as a correction value for the amount of push-in of the punch P, and for example, the amount of push-in is corrected by adding this correction value to the amount of push-in. Note that, as will be described later, the reference value (UT0) includes reference values ​​(UTa, UTb, ...) associated with the die used in bending the workpiece.

[0024] The bending machine 10 is further provided with a bending load detection sensor 18 (see FIG. 4) for detecting a bending load applied to the punch P when the upper table 11 is moved by the drive mechanism 16 to engage the punch P with the die D to bend the workpiece. When the drive mechanism 16 is constituted by, for example, a hydraulic cylinder as described above, the bending load detection sensor 18 can be configured to detect a fluid pressure.

[0025] Furthermore, the bending load detection sensor 18 can be configured to detect torque or load current when the drive mechanism 16 is configured with a motor. Alternatively, the bending load detection sensor 18 can be configured in various ways, such as a piezoelectric element provided at the mounting portion of the punch P to the upper table 11 (or the mounting portion of the die D to the lower table 12).

[0026] Next, the automatic robot 20 of the bending system 1 will be described. The automatic robot 20 includes, for example, a slider 22 that is movable in the left-right direction along a guide rail 21 that extends in the left-right direction (X-axis direction). The automatic robot 20 includes a base frame 23 placed on the slider 22.

[0027] The automatic robot 20 also includes a rotating base 24 that is provided on the base frame 23 and can rotate horizontally. A first arm 25 that can swing (rotate) up and down around a horizontally extending rotation axis is provided on the rotating base 24. A second arm 26 is provided on the tip side of the first arm 25 and can rotate around a horizontally extending rotation axis.

[0028] Further, a robot hand 27 is provided at the tip end of the second arm 26, which is rotatable about a horizontally extending rotation axis and also about a rotation axis perpendicular to the longitudinal direction of the second arm 26. During automatic operation of bending a workpiece, the automatic robot 20 carries in and supplies the workpiece to the bending machine 10 between the punch P and the die D (i.e., to the metal mold). At the same time, the automatic robot 20 unloads and carries out the bent workpiece (processed product) from the bending machine 10.

[0029] In the bending system 1 of this embodiment, the bending machine 10 and the automatic robot 20 are made to cooperate under the control of the control device 30, so that, for example, different types of products (workpieces) can be bent in an automatic operation (relay operation). Note that the relay operation here refers to an operation in which different workpieces are bent continuously in an automatic operation of a series of bending processes.

[0030] Next, the control device 30 of the bending system 1 will be described. 4, the control device 30 includes, for example, a calculation unit 31, a storage unit 32, an operation driver 33, an input interface (I / F) 34, a communication interface (I / F) 35, and a display unit 36. The calculation unit 31 has, for example, a CPU (central processing unit), and realizes the functions of the acquisition unit 2, readout unit 4, measurement unit 5, calculation unit 6, resetting unit 7, and ON / OFF setting unit 9 described above together with the input I / F 34 and communication I / F 35.

[0031] The storage unit 32 has storage media such as a random access memory (RAM), a read only memory (ROM), a hard disk drive (HDD), and a solid state drive (SSD), and stores various data in a readable and writable manner. The operation driver 33 operates the drive mechanism 16 according to an operation command from the calculation unit 31. The input I / F 34 is connected to an input unit 37 consisting of input devices such as a keyboard, a mouse, and a touch panel, and inputs input information from the input unit 37 to the calculation unit 31.

[0032] A room temperature sensor 38 consisting of a thermocouple or the like for measuring the room temperature in the installation environment of the bending machine 10 is electrically connected to the communication I / F 35, together with the above-mentioned position detection sensor 17 and bending load detection sensor 18. The display unit 36 ​​can be composed of a display, a monitor, a touch panel having the functions of the input unit 37, or the like.

[0033] On the display screen of the display unit 36, for example, a UI screen (not shown) for controlling the bending machine 10 is displayed. On this UI screen, for example, various information such as processing conditions, information indicating a correction value for change over time (ΔUT) used in bending, etc. are displayed in a visually recognizable and configurable manner. Since the configurations of these components of the control device 30 are publicly known, detailed explanations will be omitted here.

[0034] In the control device 30, a bending program stored in a memory unit 32 is called and executed by a calculation unit 31. Under the control of this program, the calculation unit 31 controls the operation of the drive mechanism 16 of the bending machine 10 and the operation of the automatic robot 20 via an operation driver 33.

[0035] The calculation unit 31 executes various calculation processes related to bending based on processing conditions such as the workpiece thickness, material, bending angle, and die conditions input via the input unit 37 and input I / F 34, and also based on detection information from the sensors 17, 18, and 38 obtained via the communication I / F 35. In the calculation processes, the calculation unit 31 also calculates the push amount of the punch P from the SS position to a reference position for the die D, the contact position where the punch P contacts the workpiece, and the relative push amount from the contact position for bending the workpiece to a desired bend angle, etc.

[0036] The control device 30 of the bending system 1 of this embodiment can execute a resetting step of resetting the above-mentioned push-in amount for each predetermined trigger condition during automatic operation of bending a workpiece by the bending machine 10. More specifically, before starting bending operation, a check operation including trial processing and accuracy adjustment of the mechanical system is performed for each product (worked piece), and the acquisition unit 2 acquires the above-mentioned reference value of the origin position. Then, the memory unit 32 links the acquired reference value to each processed piece, and constructs and stores a linking table 8 (see FIG. 5) in a database (DB) in the memory unit 32, for example.

[0037] Here, the linking table 8 will be described. FIG. 5 is a diagram for explaining a linking table between a processed product and a reference value stored in the storage unit of the control device. As shown in FIG. 5, the linking table 8 has a product column 8a, a mold used column 8b, a reference value column 8c of the origin position, a measurement value column 8d, and a correction value column 8e.

[0038] The product column 8a stores information on processed products obtained by bending a workpiece, such as "processed product A, processed product B, ...". The used die column 8b stores information on the dies used in bending each processed product in the product column 8a, linked to each processed product. Therefore, for example, the dies (used dies) used for "processed product A" are linked to "die a, die b, die c," and the dies used for "processed product B" are linked to "die b, die d, die e."

[0039] The reference value column 8c for the origin position stores information on the reference value for each processed product acquired by the acquisition unit 2, linked to each processed product. For example, the reference value "UTA (UTa, UTb, UTc)" is linked to "processed product A," and the reference value "UTB (UTb, UTd, UTe)" is linked to "processed product B."

[0040] Note that "(UTa, UTb, UTc)" in the reference value "UTA" and "(UTb, UTd, UTe)" in the reference value "UTB" represent die-specific reference values ​​linked to the die being used. The reference value stored in the reference value column 8c of the origin position can be reset, for example, by an operator's operation input. When the reference value is reset, the control device 30 can acquire and store the reference value again before the start of the next bending operation.

[0041] In the measurement value column 8d, the measurement values ​​acquired by the measurement unit 5 are stored in association with each processed product. For example, the measurement value of "processed product A" is associated with "UTA'", and the measurement value of "processed product B" is associated with "UTB'". The measurement values ​​stored in this measurement value column 8d may be stored such that the previous measurement value and the current measurement value coexist, or the previous measurement value may be overwritten by the current measurement value.

[0042] The correction value column 8e stores, for each processed product, a correction value for the amount of change over time (corrected change over time value) calculated by the calculation unit 6 based on the reference value in the reference value column 8c read by the reading unit 4 and the measurement value in the measurement value column 8d acquired by the measurement unit 5 (or the previous measurement value previously stored in the measurement value column 8d). Specifically, the correction value for "processed product A" is stored as "ΔUTA", and the correction value for "processed product B" is stored as "ΔUTB".

[0043] By using the linking table 8 configured in this manner, the reference value (and the measurement value and correction value) is linked for each workpiece and stored in the memory unit 32. This not only makes it possible to operate the machine with the correction value reflected from the first bending process, but also makes it possible to operate the machine without the operator having to check the accuracy when switching workpieces or replacing dies.

[0044] Furthermore, since the reference values ​​for each processed product (and each mold) are stored in the linking table 8 and stored in the memory unit 32, when the same processed product is processed over a period of time (processing of a repeat product) or when the same mold is used for processing across days, it is possible to calculate correction values ​​based on the measurement values ​​and set mold conditions using the reference values ​​stored in the memory unit 32 without re-taking the reference values.

[0045] That is, during bending, the control device 30 reads out the reference value linked to the workpiece to be bent from the linking table 8 using the reading unit 4. After starting the bending operation, the control device 30 obtains the measurement value of the origin position acquired by the measuring unit 5, calculates a correction value for the change over time in the amount of push-in using the calculation unit 6 based on the measurement value and the reference value, and sets the amount of push-in that reflects this correction value. Thereafter, the control device 30 calculates the amount of change over time for each predetermined trigger condition and corrects the amount of push-in.

[0046] Furthermore, the control device 30 can determine the ON / OFF state of a resetting function of the push-in amount of the punch P against the die D set in the ON / OFF setting unit 9, for example, based on input information input via the input unit 37. In the control device 30, since the ON / OFF setting unit 9 can set the resetting function to ON / OFF in this manner, the operator can arbitrarily enable (ON) or disable (OFF) the resetting function of the push-in amount regardless of, for example, the type of workpiece to be processed or the number of lots.

[0047] For example, when the reset function is enabled (ON), it is possible to automatically correct (automatic correction) changes in the bending angle due to changes over time. Also, when the reset function is disabled (OFF), it is possible to operate bending automatically or manually without setting trigger conditions, etc. When the reset function is ON, automatic correction can be performed according to various types of bending, such as when there are a large number of lots for bending, when there are a small number of lots but multiple workpieces are bent, and when bending workpieces by hand after correcting for changes over time.

[0048] For example, when the resetting execution in the resetting unit 7 is set to OFF by the ON / OFF setting unit 9 during automatic operation, the control device 30 may correct the push-in amount or the origin position using the previously calculated correction value for change over time and perform bending of the workpiece. In this way, it is possible to reduce the calculation process load of the correction value for change over time by the calculation unit 6.

[0049] The control device 30 can also determine whether or not a reset condition for resetting the push-in amount is satisfied. That is, in the control device 30 of the bending system 1, the push-in amount or the origin position is reset by the resetting unit 7 when a reset condition is satisfied after a trigger condition is satisfied, and the reset condition is when each workpiece is being loaded or unloaded into the bending machine 10.

[0050] Therefore, the control device 30 determines that the resetting condition is satisfied, for example, when the automatic robot 20 is loading or unloading a workpiece. When the resetting function is enabled, the control device 30 acquires the D-axis measurement value when the resetting condition is satisfied, and calculates the amount of change over time from the reference value (or the previous measurement value) read based on this as a correction value. Then, the push-in amount of the punch P is corrected by, for example, adding the calculated correction value to the push-in amount, and then resets it.

[0051] This makes it possible to compare the measured value with a reference value obtained in advance from the first bending process, for example, and to calculate the amount of change over time of the entire mechanical system including the die and the driving mechanism 16, etc., caused by external factors such as room temperature. The calculated amount of change over time can then be used as a correction value for the pressing amount of the punch P with respect to the bending angle (i.e., a correction value for the processing conditions).

[0052] This makes it possible to continue automatic bending operation until the end of the operation without checking the accuracy while making corrections such as adding or subtracting the push-in amount using this correction value. Therefore, it is possible to prevent deterioration of processing accuracy due to changes in the bending angle over time without the operator having to check the accuracy, and to stabilize the quality of the processed product.

[0053] 6 is a flowchart showing an outline of the processing procedure of the bending method executed by the bending system. This bending method is executed by the control device 30. The bending method according to this embodiment generally includes an acquisition step in which the acquisition unit 2 acquires, before the bending machine 10 having the punch P and the die D starts bending a workpiece, a reference value (UTA, UTB, etc.) of the origin position of the punch P with respect to the die D for each workpiece (workpiece A, workpiece B, etc.), a storage step in which the storage unit 32 associates the acquired reference value (UTA, etc.) with each workpiece (workpiece A, etc.) and stores it, a reading step in which the reading unit 4 reads out the reference value (UTA, etc.) associated with the workpiece (workpiece A, etc.) on which bending is to be performed, and a measurement step in which the measurement unit 5 measures the reference value (UTA, etc.) and stores the reference value (UTA, etc.) for each workpiece (workpiece A, etc.). The method includes a measuring step of acquiring a measurement value (UTA', UTB', etc.) of the origin position after the start of bending operation of the workpiece, a calculation step of calculating a reference value (UTA, etc.) or a time-dependent change amount from a previous measurement value based on the measured measurement value (UTA', etc.) by the calculation unit 6 as a push-in amount of the punch P against the die D or a time-dependent change correction value (ΔUTA, ΔUTB, etc.) of the origin position of the punch P based on the measured measurement value (UTA', etc.), and a resetting step of resetting the push-in amount or the origin position for each predetermined trigger condition by the resetting unit 7 using the time-dependent change correction value (ΔUTA, etc.) during automatic operation of bending the workpiece. The reference value acquired in the acquisition step by the acquisition unit 2 is acquired for each processed product obtained by bending the workpiece, and is obtained when the punch P and the die D are engaged to reach a predetermined pressure. The bending method further includes an ON / OFF setting step of setting ON / OFF of the execution of the resetting step by the resetting unit 7 by the ON / OFF setting unit 9.

[0054] Specifically, as shown in FIG. 6, the control device 30, for example by starting a bending processing program read by the calculation unit 31 from the memory unit 32, first determines whether the function of resetting the die depression amount is enabled (ON) or not (step S10) based on the operator's operation input via the input unit 37 and the input I / F 34, or via the touch panel of the display unit 36, or based on setting input from other external PCs, etc. (hereinafter referred to as "input information").

[0055] In step S10, the ON / OFF of the reset function as described above is determined based on the input information. For example, when an operator wants to perform manual bending after automatic bending, the operator can disable (OFF) the push-in amount reset function at will, thereby skipping the trigger condition setting process described later and performing manual bending.

[0056] In step S10, if it is determined that the push-in amount resetting function is enabled (ON) (YES in step S10), i.e., if the resetting process is to be executed, a trigger condition for resetting the push-in amount (for executing the resetting process) based on the amount of change over time of the entire mechanical system including the mold and drive mechanism 16 is set based on the input information (step S11).

[0057] Here, the trigger condition is, for example, at least one selected from the following (1) to (5). That is, the trigger condition is: (1) Room temperature (2) time (3) Number of processing (4) First bending process after changing the workpiece (5) Mounting the mold on the bending machine etc.

[0058] When the trigger condition set in step S11 is the room temperature as described above in (1), room temperature conditions are set such as, for example, setting the room temperature at the start of automatic operation as the reference temperature value, incrementing / decrementing the temperature change by ±10% from the reference temperature value, and repeatedly setting the temperature value at how many degrees in absolute temperature it rises or falls from the room temperature set as the reference temperature value as the next reference temperature value.

[0059] Furthermore, when the trigger condition to be set is the time in (2) above, a time condition is set, such as every 30 minutes, every hour, every two hours, etc., from the start of automatic operation. When the trigger condition to be set is the number of processed items in (3) above, a condition is set, such as the number of processed lots in every 50 lots, every 100 lots, etc., from the start of automatic operation, or the desired number of processed lots for one processed product, etc.

[0060] Furthermore, when the trigger condition to be set is the first bending after switching the workpiece as described above in (4), this corresponds to, for example, the first bending of the above-mentioned "workpiece A" after the start of automatic operation, or the first bending of "workpiece B" when bending is switched from "workpiece A" to "workpiece B." Furthermore, when the trigger condition to be set is the attachment of a die to the bending machine 10 as described above in (5), this corresponds to the attachment of a die to the bending machine 10, including the replacement of the die to be used.

[0061] In addition, when a first die (e.g., the above-mentioned "die a") attached to the bending machine 10 is replaced with a second die (e.g., the above-mentioned "die b"), the control device 30 determines that the trigger condition in (5) above is satisfied, but when the second die (e.g., "die b") is replaced (returned) with the first die (e.g., "die a"), the control device 30 does not determine that the trigger condition in (5) above is satisfied.

[0062] That is, the trigger condition of (5) includes, for example, when a die needs to be replaced between bending processes, the detection that the same die has been installed after replacement. This makes it possible to skip the calculation process and resetting process of the correction value based on the measurement value when the die is returned, and to continue the bending process by using resources such as the correction value linked to the die used before the replacement. In the following, for example, a case will be described in which one die is used for one workpiece, the time of (2) is used as the trigger condition to be set, and the resetting of the push-in amount is triggered by the elapse of 30 minutes from the start of automatic operation.

[0063] After setting the trigger conditions in step S11, the bending machine 10 and the automatic robot 20 are operated to perform trial processing of each workpiece (in this example, workpiece A and workpiece B), and a check operation is performed to ensure accuracy (step S12), and the processing state is inspected by measuring the bending angle and various dimensions (step S13). At this time, correction values ​​(processing correction values) for the bending angle, various dimensions, the pressing amount of the punch P, etc., for the previously set processing conditions are calculated and may be stored separately in the storage unit 32.

[0064] By inspecting the processing state, the reference value of the origin position of the punch P relative to the die D for each workpiece (in this example, workpiece A and workpiece B) is acquired by the acquisition unit 2 before the start of automatic bending operation (step S14), and the acquired reference values ​​are stored and memorized in the reference value column 8c for the origin position in the linking table 8 of the memory unit 32 (step S15).

[0065] Next, the calculation unit 31 calls up from the storage unit 32 a product program corresponding to the workpiece to be bent (step S16), reads out the linked reference value stored in the linking table 8 by the reading unit 4 (step S17), starts a timer or the like built into the control device 30, and starts the product processing operation (step S18). For example, if the workpiece to be bent is the above-mentioned "workpiece A," the product program corresponding to workpiece A is called up in step S16, and the linked reference value "UTA" is read out in step S17.

[0066] When the machining operation is started, first, during the initial loading, the measurement unit 5 acquires the measurement value of the origin position of the punch P (step S19), and stores it in the measurement value column 8d of the linking table 8 in the storage unit 32 as necessary. Then, the calculation unit 6 calculates a correction value for the amount of change over time from a reference value based on the measurement value, and the calculated correction value for change over time is used to correct the amount of push-in, for example by adding it to the initial amount of push-in, and the machining conditions or die conditions are set (step S20). Note that the correction of the amount of push-in is not limited to adding the correction value for change over time.

[0067] The correction value for change over time can be calculated as follows and used for setting, for example. That is, when the read-out reference value is UT0 and the measured values ​​are UT1 to UTn (n is a positive integer), for example, by comparing the measured value UT1 with the reference value UT0, a difference value ΔUT (difference between the measured value UT1 and the reference value UT0) of the reference position can be calculated as shown in FIG. 3. When the reference position is 0, this difference value ΔUT can be made positive in the direction toward the die D and negative in the direction away from the die D when viewed from the movement stroke of the punch P on the D axis. Then, the amount of change over time (correction value for change over time) ΔUT1 to ΔUTn from the reference position is calculated by the calculation unit 6 based on this difference value ΔUT, and the correction value for change over time ΔUT1 to ΔUTn is added to the initial amount of depression, for example, to correct the amount of depression, thereby setting the processing conditions or the die conditions.

[0068] An upper limit (e.g., ±0.07 mm) may be set in advance for the time-dependent change correction values ​​ΔUT1 to ΔUTn, and when the time-dependent change correction values ​​ΔUT1 to ΔUTn calculated in the calculation step exceed the upper limit, the resetting unit 7 may reset the push-in amount or the origin position using the previously calculated time-dependent change correction value ΔUTn-1 or the upper limit. This allows automatic operation to be continued by adopting an appropriate correction value, even if a time-dependent change occurs that significantly disrupts the processing accuracy of the bending process.

[0069] After the processing conditions or die conditions are set in this way, the bending process (step S21) of the workpiece corresponding to the processed product is automatically performed under the set conditions. During the automatic operation of this bending process, it is determined whether or not the trigger condition has been satisfied (whether or not the trigger condition has been reached) based on the time measured by the timer, that is, whether or not 30 minutes have passed since the start of the automatic operation (step S22).

[0070] If it is determined that 30 minutes have passed since the start of automatic operation and the trigger condition is satisfied (YES in step S22), it is determined whether or not the reset condition for resetting the next push-in amount is satisfied, that is, whether a workpiece is being loaded or unloaded (step S23). If it is determined that 30 minutes have not passed since the start of automatic operation and the trigger condition is not satisfied (NO in step S22), the process proceeds to step S24 described later.

[0071] In step S23, if it is determined that the resetting condition is satisfied (YES in step S23), the process proceeds to step S19 to obtain the next measurement value (UT2 to UTn) of the origin position, and the subsequent processes are repeated. On the other hand, if it is determined that the resetting condition is not satisfied (NO in step S23) or if it is determined that the trigger condition is not satisfied (NO in step S22), it is determined, for example, whether or not the workpiece is to be switched (step S24).

[0072] Then, when it is determined that the workpiece is to be switched, that is, for example, that the workpiece is to be switched from "workpiece A" to "workpiece B" (YES in step S24), the process proceeds to step S16, where the product program corresponding to workpiece B is called, and the reference value "UTB" associated therewith is read out in step S17, and the subsequent processes are repeated. When the workpiece is switched, for example, steps S17 and S19 may be omitted, and the time-varying correction value (ΔUT) for the workpiece before the switch may be continued and used. In this way, it is possible to eliminate the need for accuracy confirmation work when the workpiece is switched.

[0073] On the other hand, if it is determined that the workpiece will not be switched (NO in step S24), it is determined whether or not the end conditions for the automatic operation, such as the number of workpiece processing lots (e.g., 50 lots) or processing time (e.g., 3 hours) set in advance, have been reached (step S25), and if it is determined that the end conditions have not been reached (NO in step S25), the process proceeds to step S21 and the automatic operation of the workpiece bending process (step S21) continues. On the other hand, if it is determined that the end conditions have been reached (YES in step S21), the automatic operation is terminated, and the processing of the bending method according to this flowchart is terminated.

[0074] If the automatic operation of the bending process is continued in step S21, it is determined whether the trigger condition is satisfied again during the automatic operation, for example, whether a predetermined time (30 minutes) has passed since the previous elapsed time (step S22). If the predetermined time has not passed, it is determined that the trigger condition is not satisfied (NO in step S22) and the process proceeds to step S24, but if the predetermined time has passed, it is determined that the trigger condition is satisfied (YES in step S22) and it is determined whether the reset condition for the next reset is satisfied (step S23). If the reset condition is satisfied (YES in step S23), the process proceeds to step S19 and the subsequent processes are repeated.

[0075] In this way, the bending system 1 of the first embodiment acquires and associates and stores the reference value of the origin position of the punch P for each workpiece before the start of automatic operation, reads out the reference value associated with the workpiece on which bending is actually performed, and then acquires the measured value of the origin position after the start of automatic operation. Then, a time-change correction value for the amount of change from the reference value over time is calculated based on the measured value, and using this, bending can be performed under processing conditions including the push-in amount reflecting the time-change correction value from the initial bending.

[0076] In addition, the resetting of the push-in amount that reflects the correction value for the change over time can be repeated multiple times (e.g., n times) until the end condition of the automatic operation is reached, for example, at the stage where the resetting condition is satisfied each time the trigger condition is satisfied, thereby enabling the bending process to be automatically operated. This reduces the burden on the operator of checking the accuracy without stopping the automatic operation, and also makes it possible to stabilize the quality of the processed product.

[0077] In addition, in the above step S10, if it is determined that the push-in amount resetting function is not enabled (ON) (disabled (OFF)) (NO in step S10), the above trigger condition setting process (step S11) is not performed, and a check operation (step S26) is performed by, for example, the bending machine 10 and the automatic robot 20, and the processing state is inspected (step S27).

[0078] Then, a product program corresponding to the workpiece on which bending is to be performed is called from memory unit 32 (step S28), and time-dependent correction values, such as a time-dependent correction value preset for the workpiece, a time-dependent correction value used in a previous bending process on the workpiece and carried over without being cleared, are read from memory unit 32, and the amount of depression is corrected using these, and the processing conditions or die conditions are set (step S29).

[0079] After that, the product processing operation is started (step S30), and the bending process of the workpiece (step S31) is performed automatically or manually. Then, it is determined whether or not the end condition of the operation is reached (step S32), and if the end condition is not reached (NO in step S32), the bending process (step S31) is continued, but if the end condition is reached (YES in step S32), the bending operation is ended, and the processing of the bending method according to this flowchart is ended.

[0080] In the first embodiment described above, the correction values ​​ΔUT1 to ΔUTn for the amount of push-in are calculated by comparing the reference value UT0 with each of the measured values ​​UT1 to UTn to calculate the difference value ΔUT, but for example, the difference value ΔUT may be calculated by comparing the acquired measured value (UTn) with the previously acquired measured value (UTn-1). Even if the amount of push-in is corrected using the correction values ​​ΔUT1 to ΔUTn for the amount of push-in calculated in this way, it is possible to perform automatic operation of the bending process as described above.

[0081] In the first embodiment described above, the resetting condition is that the automatic robot 20 is loading a workpiece, but this condition may refer to that the automatic robot 20 is unloading a workpiece, or that the workpiece is being loaded / unloaded manually. In this way, if the measured value is acquired during loading / unloading of the workpiece and the push-in amount is reset, there is no effect on the operation of automatic bending. Therefore, during automatic operation, correction can be made without stopping the automatic operation, eliminating the need for the operator to check the accuracy.

[0082] Furthermore, in the above-mentioned first embodiment, the pushing amount of the punch P (mold) against the die D used for product processing is measured and obtained, but the present invention is not limited to this. The pushing amount of a die other than the die actually used (for example, the punch P against the die D not used for bending that is attached to the upper die holder 14 and the lower die holder 15) may be measured and stored in advance in the storage unit 32 in association with each other. In this way, it is possible to calculate a correction value for change over time similar to that described above. In other words, as long as the above-mentioned reference value UT0 and the measured value UTn can be obtained from the same die, the effect of this embodiment can be achieved regardless of whether the die is used or unused for bending.

[0083] [Modification of the first embodiment] In the bending method of the first embodiment described above, relay operation in which different workpieces are successively bent in an automatic operation of a series of bending processes has been mainly described as an example, but this bending method can also be applied to bending processes in which a die change is required between bending processes. That is, although not shown in the drawings, in the bending method of the modified example, a reference value for each die is acquired in the acquisition process of step S14, and the reference value is associated with each die and stored in the storage process of step S15.

[0084] Then, all the reference values ​​associated with the dies to be used first to nth in the bending process, as specified in the program called in step S16, are read out in a reading process in step S17, and after the start of processing, measurement values ​​based on the currently used die are obtained (step S19), and bending processing is performed based on the obtained measurement values ​​and a correction value for change over time calculated based on the reference values ​​of the die used (step S21).

[0085] During the automatic operation of this bending process, a determination is made as to whether or not a die (including automatic die mounting) has been performed based on die change (including automatic die change by the automatic robot 20) as a trigger condition (step S22). For example, when automatic die mounting by the automatic robot 20 has occurred (YES in step S22) and the reset condition is satisfied (YES in step S23), a measurement value based on the die used that was mounted except when the die was returned as described above is obtained (step S19). A correction value for change over time is calculated based on this measurement value and the reference value for the die used that was read out, and bending is performed until the workpiece is switched or the operation termination condition is satisfied (step S21).

[0086] In this way, in the bending method of the modified example, even if bending is performed in which the dies used are switched in bending of one workpiece, it is possible to stabilize the quality of the workpiece while reducing the burden of the accuracy confirmation work on the operator. Note that, for example, when a die set consisting of a plurality of dies is replaced as a unit of die replacement, the reference value associated with each die may be stored in association with each die set.

[0087] [Second embodiment] 7 is an explanatory diagram showing an overview of a general die used in a bending machine of a bending system according to a second embodiment of the present invention. In the following description, the same reference numerals are used for components that are the same as or correspond to those in the first embodiment and its modified examples, and therefore duplicated descriptions will be omitted.

[0088] The bending method according to the second embodiment differs from the bending method according to the first embodiment in that when the workpiece is clamped between the punch P and the die D, i.e., when the workpiece is clamped in the metal mold, the origin position of the punch P is reset based on the D-axis position, and the amount of depression is not changed.

[0089] That is, the reference value and the measured value are obtained based on the D-axis position when the workpiece is sandwiched between the punch P and the die D. In this case, in the second embodiment, the origin position of the punch P is set as the position (reference position (0 mm)) when the tip of the punch P is brought into contact with the surface of the workpiece with a workpiece having a thickness T placed on the die D, as shown in Fig. 7. The push-in amount ST represents the distance from this reference position to the groove bottom (lower end) of the V-groove portion of the die D.

[0090] In the bending method of the second embodiment, for example, after the automatic operation of bending starts, the origin position of the punch P is measured to calculate a correction value for change over time, and thereafter, the origin position of the punch P is reset using the correction value for change over time for each predetermined trigger condition. In this way, the origin position of the punch P is reset without changing the push-in amount, for example, while the automatic operation of bending continues until the end of the operation. In the bending method of the second embodiment, too, the change in the bending angle due to change over time can be corrected without stopping the operation, and the quality of the processed product can be stabilized while reducing the burden of the accuracy confirmation work on the operator.

[0091] [Third embodiment] Fig. 8 is a flowchart showing an outline of the processing procedure of a bending method according to a third embodiment of the present invention. The third embodiment assumes a case in which a correction value for change over time is used in the case of manual bending. Here, the processing will be described as a continuation of the processing of the bending method according to the flowchart of Fig. 6, but is not limited to this.

[0092] As shown in Fig. 8, after the process in Fig. 6 is completed, the calculation unit 31 of the control device 30 judges whether or not the power to the bending machine 10 is automatically shut off (step S40). If it is judged to be an automatic power shutoff (YES in step S40), the control device 30 temporarily stores the mold used for bending by the automatic robot 20 in a mold stocker or the like (step S41), and shuts off (OFF) the power (step S42).

[0093] The control device 30 then waits until the bending system 1 is started up by turning on the power, etc. (NO in step S43), and when the bending system 1 is started up (YES in step S43), a program corresponding to the workpiece to be manually bent is called up, for example, by an operator's operation input via the input unit 37 and the input I / F 34 (step S44), and for example, whether or not the automatic robot 20 has automatically attached a die to the bending machine 10 is determined as a trigger condition (step S45).

[0094] If it is determined that the mold is mounted and the trigger condition is satisfied (YES in step S45), it is determined whether the mounted mold is in the initial state (step S46). If it is determined that the mounted mold is not in the initial state (NO in step S46), the process proceeds to step S52, which will be described later, and the mold is initialized.

[0095] If it is determined that the die is in its initial state (YES in step S46), the reference value associated with the hand-bent workpiece or the reference value associated with the attached die is read from the linking table 8 in the memory unit 32 (step S47), the measurement value of the origin position is obtained (step S48), a correction value for change over time based on the measurement value and the reference value is calculated to set the processing conditions, etc. (step S49), and the workpiece is manually bent (step S50).

[0096] Finally, it is determined whether the end condition for the manual bending has been reached (step S51). If it is determined that the end condition has not been reached (NO in step S51), the manual bending process (step S50) is continued, but if it is determined that the end condition has been reached (YES in step S51), the manual bending operation is terminated and the processing of the bending method according to this flowchart is terminated.

[0097] In addition, if it is determined in step S40 above that there is no automatic power cut (NO in step S40), the control device 30 executes a mold initialization process including, for example, automatic mold change by the automatic robot 20 and mold storage in which the mold being used is temporarily stored in a mold stocker or the like (step S52), and then proceeds to step S44 above to repeat the subsequent processes.

[0098] In this way, even when bending is performed manually, bending can be performed without the need for an operator to check the accuracy, and similar to the effects of the first and second embodiments, it is possible to reduce the burden of checking the accuracy and stabilize the quality of the processed product. Note that, for example, it is also possible to skip steps S40 to S43, S46, and S52 to simplify the manual bending method.

[0099] [Other embodiments] FIG. 9 is a flowchart showing an outline of a processing procedure of a bending method according to another embodiment of the present invention. In the bending method according to another embodiment, the change in bending angle due to the aging of the automatically operated bending system 1 can be corrected without stopping the operation, and the productivity and quality can be improved.

[0100] In the control device 30 of this embodiment, for example, based on input information input via the input unit 37, it is possible to determine whether to turn on or off a function for resetting the amount of pressing of the punch P against the die D. For example, when the number of lots of bending processing is large, the operator can arbitrarily enable (ON) the function for resetting the amount of pressing, thereby automatically correcting changes in the bending angle due to changes over time. Also, when the number of lots of bending processing is small, the operator can arbitrarily disable (OFF) the function for resetting the amount of pressing, thereby enabling automatic operation without setting trigger conditions, etc.

[0101] The control device 30 may also determine whether or not the acquisition condition for setting the initial reference position and the reset condition for resetting the push-in amount are satisfied. The control device 30 determines that the acquisition condition and the reset condition are satisfied when, for example, the automatic robot 20 is loading or unloading a workpiece. When the reset function is enabled, the control device 30 waits until the acquisition condition and the reset condition are satisfied, acquires the value of the D axis as the reference position when the acquisition condition is satisfied, and when the reset condition is satisfied, calculates the amount of change over time as a correction value and resets the push-in amount of the punch P after correcting it, for example by adding the correction value to the push-in amount.

[0102] The control device 30 also executes a resetting step of resetting the above-mentioned push-in amount for each predetermined trigger condition during automatic operation of bending a workpiece by the bending machine 10. More specifically, when automatic operation of bending starts, the initial reference position is acquired to set the push-in amount, and thereafter, the amount of change over time in the reference position is calculated for each predetermined trigger condition to correct the push-in amount.

[0103] As a result, for example, by comparing a later acquired reference position with an initially acquired reference position, the amount of change over time of the entire mechanical system including the die and drive mechanism 16 caused by external factors such as room temperature can be calculated, and the calculated amount of change over time can be used as a correction value for the punch P thrust amount related to the bending angle (i.e., a correction value for the processing conditions), and the thrust amount can be corrected by using this correction value to add or subtract, and the automatic operation of the bending process can be continued until the end of the operation. Therefore, the change in the bending angle caused by the change over time can be corrected without stopping the bending process operation, making it possible to improve the productivity and quality of the bent product.

[0104] As shown in FIG. 9, the control device 30 starts the bending program read by the calculation unit 31 from the memory unit 32, and first determines whether the function of resetting the die depression amount is enabled (ON) or not based on input information such as the operation input by the operator (user) as described above or the setting input as described above (step S100).

[0105] That is, in this step S100, the ON / OFF of the reset function is determined based on the input information. For example, as described above, when the number of bending lots is small, the operator can disable the reset function of the push-in amount at his / her discretion, thereby skipping the setting process of the trigger condition described later and performing automatic operation.

[0106] In this step S100, when it is determined that the push-in amount resetting function is enabled (ON) (YES in step S100), that is, when the resetting step is executed, a trigger condition for resetting the push-in amount (for executing the resetting step) based on the input information is set (step S101). As the trigger condition, for example, at least one of the time, room temperature, and number of processing is set.

[0107] Here, if the trigger condition to be set is time, a time condition such as every hour or every two hours from the start of automatic operation is set. If the trigger condition to be set is room temperature, a room temperature condition is set such that, for example, the room temperature at the start of automatic operation is set as a reference value and the temperature change is incremented / decremented by ±10% from the reference value, or the value at which the absolute temperature rises or falls from the room temperature set as the reference value is repeatedly set as the next reference value. If the trigger condition to be set is the number of processing, a condition is set such as the number of processing lots, for example, every 50 lots or every 100 lots from the start of automatic operation.

[0108] Other trigger conditions may be set, for example, when a mold needs to be replaced between processes and the same mold is detected as being inserted after replacement. In the following, room temperature is used as the trigger condition to be set, and a specified temperature change increment / decrement from the room temperature at the start of automatic operation is used as a trigger to reset the push-in amount.

[0109] After the trigger conditions are set in this way, the bending machine 10 and the automatic robot 20 are operated to perform a test processing (check operation) of the workpiece (step S102), the bending angle and various dimensions are measured to inspect the processing state (step S103), and correction values ​​(processing correction values) related to the bending angle and various dimensions for the set processing conditions, the push-in amount of the punch P, etc. are calculated. Then, the processing correction values ​​are input and set based on the input information (step S104), the temperature is measured by the room temperature sensor 38, and the product processing operation is started (step S105).

[0110] When the machining operation is started, first, it is determined whether or not the acquisition condition of the reference value for setting the initial push-in amount is satisfied (step S106). In this embodiment, this acquisition condition indicates that the automatic robot 20 is loading a workpiece. Therefore, the control device 30 waits until the acquisition condition is satisfied (for example, until the initial workpiece is being loaded) (NO in step S106), and when the acquisition condition is satisfied (loading is in progress) (YES in step S106), the control device 30 acquires the initial reference position value (reference value UT0) and sets the die conditions (step S107).

[0111] If the acquired reference value UT0 is stored in, for example, the storage unit 32, when the same die is used to process a product across days, this reference value UT0 can be used to set the die conditions, so there is no need to retake the reference value UT0. Then, the bending process (step S108) of the workpiece is automatically performed under the processing conditions including the set die conditions.

[0112] During automatic operation of the bending process, it is determined whether the trigger condition is satisfied (whether the trigger condition is reached) based on the room temperature measured by the room temperature sensor 38, that is, whether a predetermined temperature change has been incremented / decremented from the room temperature at the start of automatic operation (step S109). If it is determined that the predetermined temperature change has not been incremented / decremented from the room temperature at the start of automatic operation and the trigger condition is not satisfied (NO in step S109), the bending process in step S108 is continued.

[0113] On the other hand, if it is determined that the trigger condition is satisfied by incrementing / decrementing the predetermined temperature change from the room temperature at the start of automatic operation (YES in step S109), it is determined whether the reset condition for resetting the next depression amount is satisfied (step S110). That is, as described above, the control device 30 waits until the reset condition is satisfied (NO in step S110), and when the reset condition is satisfied (YES in step S110), it acquires the value of the next reference position (measured value UT1) (step S111).

[0114] By comparing the measured value UT1 thus obtained with the reference value UT0 obtained initially, a difference value ΔUT (difference between the measured value UT1 and the reference value UT0) of the reference position can be calculated as shown in Fig. 3. When the reference position is set to 0, for example, this difference value ΔUT can be made positive in the direction toward the die D and negative in the direction away from the die D in terms of the movement stroke of the punch P on the D axis. Then, based on this difference value ΔUT, a correction value (amount of change over time) ΔUT1 of the first change over time from the reference position is calculated, and the correction value ΔUT1 is added to the initial amount of push-in to correct the amount of push-in and set the die conditions (step S112). Note that the correction of the amount of push-in is not limited to adding the correction value ΔUT1.

[0115] After the die conditions are set, it is determined whether or not an end condition for automatic operation, for example a preset number of workpiece processing lots (e.g., 200 lots), has been reached (step S113), and if it is determined that the end condition has not been reached (NO in step S113), automatic operation of the workpiece bending process (step S108) is continued based on the processing conditions including the die conditions set in step S112. On the other hand, if it is determined that the end condition has been reached (YES in step S113), the automatic operation is terminated and the processing of the bending method according to this embodiment is terminated.

[0116] If automatic operation of the bending process is continued in step S108, it is determined whether or not a trigger condition has been satisfied during the automatic operation, for example, whether a predetermined temperature change has been incremented / decremented from the room temperature that was previously incremented / decremented (step S109). If the predetermined temperature change has not been incremented / decremented, it is determined that the trigger condition has not been satisfied (NO in step S109) and the bending process is continued as is, but if there has been a predetermined temperature change, it is determined that the trigger condition has been satisfied (YES in step S109), and it is determined whether or not the reset condition for the next reset has been satisfied (step S110).

[0117] Here, the control device 30 waits until the reset condition is satisfied (NO in step S110), and when the reset condition is satisfied (YES in step S110), acquires the value of the next reference position (measured value UT2) (step S111).Then, the control device 30 compares this measured value UT2 with the initial reference value UT0 to calculate the difference value ΔUT of the reference position (difference between the measured value UT2 and the reference value UT0), calculates the correction value (amount of change over time) ΔUT2 of the second change over time from the reference position, and corrects the push-in amount as described above by adding the correction value ΔUT2 to the initial push-in amount, for example, to set the mold condition (step S112), executes the next judgment process (step S113), and repeats the subsequent processes.

[0118] In this way, the bending system 1 of another embodiment can repeatedly acquire the value of the reference position multiple times (for example, n times) until the end condition of the automatic operation is reached, for example, at the stage where the reset condition is satisfied each time the trigger condition is satisfied. This allows the reference value UT0 of the reference position acquired initially to be compared with the measured values ​​UT1 to UTn of the reference position acquired the first to nth times, respectively, to calculate the difference value ΔUT associated with the aging of the die and the mechanical system, and to calculate the correction values ​​ΔUT1 to ΔUTn of the aging of the first to nth times. Then, the push-in amount is corrected using these correction values ​​ΔUT1 to ΔUTn, for example, by adding each correction value ΔUT1 to ΔUTn to the push-in amount, and the automatic operation of the bending process can be continued, so that the change in the bending angle due to the aging can be corrected without stopping the automatic operation, and at the same time, productivity and quality can be improved.

[0119] If it is determined in step S100 that the push-in amount resetting function is not valid (disabled (OFF)) (NO in step S100), the above-mentioned trigger condition setting process (step S101) is not carried out, and trial processing is performed by the bending machine 10 and the automatic robot 20 (step S114), the processing state is inspected (step S115), and a processing correction value is calculated. Then, this processing correction value is input and set based on the input information (step S116), product processing operation is started (step S117), and the workpiece bending process (step S118) is performed automatically or manually.

[0120] Thereafter, it is determined whether or not the end condition for the operation has been reached (step S119). If the end condition has not been reached (NO in step S119), the bending process (step S118) is continued, but if the end condition has been reached (YES in step S119), the bending operation is terminated and the processing of the bending method according to this embodiment is terminated.

[0121] In another embodiment, for example, each time the reference position value is acquired, the acquired measurement value may be compared with the previously acquired measurement value (or reference value) to calculate the difference value ΔUT. Even if the push-in amount is corrected using the correction values ​​ΔUT1 to ΔUTn calculated in this way, it is possible to continue the automatic operation of the bending process as described above.

[0122] In addition, the acquisition conditions or the reset conditions for resetting may be performed while the automatic robot 20 is unloading the workpiece. In this way, if the reference position is acquired or the push-in amount is reset while the workpiece is being loaded / unloaded, there is no effect on the operation of the automatic bending process, so that corrections can be made more reliably without stopping the automatic operation.

[0123] Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the scope of the invention and its equivalents described in the claims.

[0124] For example, in the other embodiments described above, a correction value is obtained based on a reference position using the punch P and die D molds to correct the amount of depression, but this is not limited to this, and the correction value may also be obtained by calculating, for example, the amount of elongation (change) of the support part 13 itself when there is no load, or the amount of strain due to the influence of load based on the elongation of the support part 13 itself when a predetermined load is applied, measured using a strain gauge or the like provided on the support part 13 of the bending machine 10, and then calculating based on the result of the calculation.

[0125] The bending methods described in the above-mentioned embodiments can be realized by executing a bending program prepared in advance on a computer such as a personal computer, a workstation, etc. This bending program may be recorded on a computer-readable recording medium such as an HDD, SSD, CD-ROM, DVD, or memory card, and executed by the computer by reading it from the recording medium, and may also be a transmission medium that can be distributed via a network such as the Internet. [Explanation of symbols]

[0126] 1 Bending system 2 Acquisition part 4 Readout section 5 Measuring part 6 Calculation section 7 Resetting section 8. Linking Table 9 ON / OFF setting section 10 Bending machine 11 Upper table 12 Lower Table 13 Support part 14 Upper holder 15 Lower holder 16 Drive mechanism 17 Position detection sensor 18 Bending load detection sensor 20. Automatic Robot 30 Control device 32 Storage section

Claims

1. An acquisition step of acquiring a reference value of an origin position of the punch relative to the die for each workpiece before starting an operation of bending a workpiece using a bending machine having a punch and a die; a storage step of storing the acquired reference values ​​in association with each of the processed products; a reading step of reading the reference value associated with a workpiece to be bent; a measuring step of acquiring a measurement value of the origin position after starting the bending operation of the workpiece; a calculation step of calculating an amount of change over time from the reference value or a previous measured value based on the measured measured value as a correction value for change over time of the amount of push-in of the punch into the die or the origin position of the punch; A resetting step of resetting the push-in amount or the origin position for each predetermined trigger condition using the time-dependent change correction value during automatic operation of the bending process of the workpiece, The calculated correction value for the change over time is associated with each of the processed products and stored. When the processed product is changed, the steps after the storing step are repeated. Bending method.

2. The reference value includes a reference value associated with a die used in bending the processed product. The bending method according to claim 1.

3. The trigger condition is at least one selected from the following (1) to (5): (1) Room temperature (2) Time (3) Number of processing (4) The first bending process after switching the processed product (5) Mounting the mold on the bending machine The bending method according to claim 1 or 2.

4. When the first die attached to the bending machine is replaced with the second die, it is determined that the trigger condition in (5) is satisfied; When the second mold is replaced with the first mold, it is not determined that the trigger condition in (5) is satisfied. The bending method according to claim 3.

5. the push-in amount or the origin position is reset when a reset condition is satisfied after the trigger condition is satisfied, The reset condition is during loading or unloading of the workpiece to or from the bending machine for each of the processed products. The bending method according to any one of claims 1 to 4.

6. An ON / OFF setting step for setting ON / OFF of the execution of the resetting step is provided. The bending method according to any one of claims 1 to 5.

7. When the execution of the resetting process is set to OFF during the automatic operation, the push-in amount or the origin position is corrected using the most recently calculated correction value for change over time, and bending of the workpiece is performed. The bending method according to claim 6.

8. The reference value and the measured value are obtained based on the D-axis position when a predetermined load is applied to the punch and the die. The bending method according to any one of claims 1 to 7.

9. The reference value and the measured value are obtained based on the D-axis position when the workpiece is sandwiched between the punch and the die. The bending method according to any one of claims 1 to 7.

10. An upper limit value is set in advance for the correction value for change over time, and if the correction value for change over time calculated in the calculation step exceeds the upper limit value, the push-in amount or the origin position is reset using the correction value for change over time calculated previously or the upper limit value. The bending method according to any one of claims 1 to 9.

11. A bending machine having a punch and a die; A control device that controls the bending machine to perform bending; Equipped with The control device includes: An acquisition unit that acquires a reference value of an origin position of the punch with respect to the die for each workpiece before the bending machine starts bending the workpiece; a storage unit that stores the acquired reference values ​​in association with each of the processed products; A reading unit that reads out the reference value associated with a workpiece to be bent; a measurement unit for acquiring a measurement value of the origin position after the bending operation of the workpiece is started; a calculation unit that calculates an amount of change over time from the reference value or a previous measured value based on the measured measured value as a correction value for change over time of the amount of push-in of the punch into the die or an origin position of the punch; A resetting unit that resets the push-in amount or the origin position for each predetermined trigger condition using the time-dependent change correction value during automatic operation of bending the workpiece; Including, The storage unit stores the calculated correction values ​​for the change over time in association with each of the processed products, The control device is configured to repeat the processes performed by the reading unit, the measuring unit, the calculating unit, and the resetting unit when the processed product is switched. Bending system.

12. The reference value includes a reference value associated with a die used in bending the processed product. The bending system according to claim 11.

13. The trigger condition is at least one selected from the following (1) to (5): (1) Room temperature (2) Time (3) Number of processing (4) The first bending process after switching the processed product (5) Mounting the mold on the bending machine The bending system according to claim 11 or 12.

14. The control device includes: When the first die attached to the bending machine is replaced with the second die, it is determined that the trigger condition in (5) is satisfied; When the second mold is replaced with the first mold, it is not determined that the trigger condition in (5) is satisfied. The bending system according to claim 13.

15. the push-in amount or the origin position is reset when a reset condition is satisfied after the trigger condition is satisfied, The reset condition is during loading or unloading of the workpiece to or from the bending machine for each of the processed products. The bending system according to any one of claims 11 to 14.

16. The control device includes: An ON / OFF setting unit that sets ON / OFF of the execution of the resetting in the resetting unit The bending system according to any one of claims 11 to 15.

17. The control device includes: When the execution of resetting in the resetting unit is set to OFF by the ON / OFF setting unit during the automatic operation, the push-in amount or the origin position is corrected using the most recently calculated time-dependent change correction value, and bending of the workpiece is performed. The bending system according to claim 16.

18. The reference value and the measured value are obtained based on the D-axis position when a predetermined load is applied to the punch and the die. The bending system according to any one of claims 11 to 17.

19. The reference value and the measured value are obtained based on the D-axis position when the workpiece is sandwiched between the punch and the die. The bending system according to any one of claims 11 to 17.

20. An upper limit value is set in advance for the correction value for change over time, The resetting unit is When the correction value for the change over time calculated by the calculation unit exceeds the upper limit value, the push amount or the origin position is reset using the correction value for the change over time calculated previously or the upper limit value. The bending system according to any one of claims 11 to 19.

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