JPWO2011096442A1 - Bending method and system using a press brake - Google Patents

Abstract

The target pressing amount of the upper die of the final workpiece can be calculated by one bending process. An upper portion is set by a set push amount (St1) corresponding to a set finish angle (θ1) set under a condition that is larger than a specific finish angle (θF) of a workpiece unloaded at the time of contact with an inclined surface of a V-groove. The mold is pushed into the V groove, and the finished angle (θM) of the workpiece is measured. In the St-θ graph showing the relationship between the indentation amount (St) and the finishing angle (θ), the measurement point determined by the actually measured finishing angle (θM) and the set indentation amount (St1), and the specific finishing angle (θF) and specification The slope (f1) of the straight line passing through the inflection point determined by the specific pushing amount (StF) corresponding to the finishing angle (θF), and the target pushing amount (corresponding to the inflection point and the target finishing angle (θT) ( The target push amount (StT) is calculated so that the slope (f2) of the straight line passing through the machining point determined by StT) satisfies a predetermined relationship. [Selection] Figure 5

Description

  The present invention relates to a bending method and a bending processing system using a press brake that bends a workpiece to a target angle by relatively pushing an upper die into a V groove of a lower die. is there.

  As shown in Patent Document 1, the conventional typical press brake has a lower mold having a V-groove opposed to a lower position of the upper mold and moves the upper and lower molds relatively close to and away from each other. The workpiece is bent at a predetermined angle by relatively pushing the upper die into the V groove of the lower die. For example, in a press brake of a type in which the ram with the upper mold attached is moved up and down, a workpiece such as a plate shape is supported on the lower mold, and the pressure applied by the upper mold moved down together with the ram is applied. By pushing the upper die into the V-groove while acting on the workpiece, the workpiece is bent at a predetermined angle. That is, the angle at which the workpiece is bent is determined by the moving distance of the upper die that moves from the contact to the lower end position (the amount of pressing of the upper die (stroke)).

  The bending angle of the workpiece when the upper die for pressing the workpiece is unloaded and removed from the die is larger than the bending angle when the workpiece is pressurized with the upper die by the spring back. It is generally known that For this reason, in order to bend the workpiece to a target angle, the upper die is determined based on the workpiece material, plate thickness, upper and lower mold shapes, V-groove angle and width, machine rigidity, etc. The amount of indentation is calculated, and the workpiece is bent. In the present specification, the bending angle of the workpiece when the workpiece is sandwiched between the upper and lower molds is referred to as the “clipping angle”, and the bending angle of the workpiece when unloaded and spring-backed is expressed as “ It is called “finish angle”.

JP 2002-79319 A

  By the way, the above-described pressing amount of the upper mold is created by previously creating a database of the influence of calculation factors such as workpiece material, plate thickness, upper and lower mold shapes, V-groove angle and width, and machine rigidity. It is calculated based on the calculation factor that is stored in the database. However, the database does not completely match the values based on the workpieces used for actual machining, press brakes, etc., and has slight errors. Therefore, the final workpiece finishing angle can be determined by a single bending process. It was difficult to set the target value.

  For this reason, when bending a workpiece, a test bending process is performed in order to check the processing accuracy according to the calculated amount of pressing of the upper die and to correct the amount of pressing of the upper die. Yes. That is, the bending work is performed on the work for trial bending, the finishing angle of the work subjected to the bending work is measured, and the pushing amount of the upper mold is increased or decreased according to the finishing angle of the work. Then, the next workpiece is bent on the basis of the corrected amount of pressing of the upper die, and the process of measuring the finished angle and re-correcting the amount of pressing of the upper die is repeated several times. Through repeated trial and error, an accurate upper die push-in amount that can bend the workpiece to the final target angle is obtained. In this way, it is necessary to perform multiple trial bendings until the indentation amount of the upper die that achieves the target finish angle is obtained, and production due to loss of time and materials before the workpiece can be bent. The decline in sex was a major problem. In particular, when the upper die is pushed into the V-groove and bent so that the workpiece contacts the inclined surface of the V-groove, the workpiece is bent by contacting the workpiece with the inclined surface of the V-groove. Since the characteristics greatly change, it is difficult to obtain an accurate indentation amount of the upper die by calculation, and a plurality of trial bendings are indispensable, and improvement has been strongly desired.

  On the other hand, as a method of bending a workpiece to a target finish angle while reducing the trial bending of the workpiece as described above, the bending angle (sandwich angle) of the workpiece in the in-process of bending as described in Patent Document 1 described above. ) Is known. In other words, a sensor that contacts the workpiece is placed on the upper die, and during the bending process while measuring the clamping angle of the workpiece, the workpiece is unloaded once and the finished angle of the workpiece is measured. The amount of spring back is measured from the difference between the sandwiching angle and the finished angle, and the workpiece is further bent by obtaining an additional required amount of pushing based on the result. Even when adopting an in-process machining method using such a sensor, if it is necessary to bend the workpiece so that the workpiece contacts the inclined surface of the V-groove during bending, Since the bending characteristics change greatly, it is still necessary to perform the work bending process a plurality of times, and the work efficiency is not excellent. Also, in this machining method, the installation of the sensor leads to an increase in the size of the mold and the complexity of the device, leading to a significant restriction on the shape of the work that can be machined, thereby reducing the versatility of the device. In addition, depending on the material of the workpiece, foreign matter adheres to the sensor measurement surface due to contact with the sensor, and it is pointed out that the measurement accuracy cannot be guaranteed. Moreover, it is necessary to use an expensive sensor in order to enable high-precision measurement, which increases the manufacturing cost of the apparatus. For this reason, the in-process bending method using the above-described sensor is generally difficult to adopt.

  Accordingly, the present invention has been proposed to solve this problem in view of the above-mentioned problems inherent in the prior art, and the final target finish angle of the workpiece by performing a single bending process. It is an object of the present invention to provide a bending method and a bending system using a press brake capable of obtaining the pressing amount of the upper die corresponding to the above.

In order to overcome the above-mentioned problems and achieve the intended purpose, a bending method using a press brake according to claim 1 of the present application,
When the upper mold (26) is relatively pushed into the V-groove (20) of the lower mold (18) disposed opposite to the upper mold (26), the lower mold (18) Bending using a press brake that makes the workpiece (W) contact the inclined surface of the V-groove (20) and performs a bending process so that the finished angle of the workpiece (W) becomes a predetermined target finished angle (θ _T ). A processing method,
Set the finished angle (θ ₁ ) of the workpiece (W) obtained by bending in the air bend state of the workpiece (W) unloaded when the workpiece (W) contacts the inclined surface of the V groove (20). Set under conditions that are larger than the specific finish angle (θ _F ), and push the upper die (26) into the V groove (20) with the set push amount (St ₁ ) corresponding to the set finish angle (θ ₁ ). The workpiece (W) is bent, and the measured finished angle (θ _M ) of the workpiece (W) bent at the set push-in amount (St ₁ ) is measured.
In the St-θ graph showing the relationship between the pushing amount (St) of the upper die (26) and the finishing angle (θ) of the workpiece (W), the measured finishing angle (θ _M ) and the set pushing amount (St ₁ ) A point determined by a specific indentation amount (St _F ) that is the indentation amount of the upper die (26) corresponding to the specific finishing angle (θ _F ) and the specific finishing angle (θ _F ) Is the inflection point, and the target indentation amount (St _T ) that is the indentation amount of the upper die (26) corresponding to the target finish angle (θ _T ) is taken as the machining point, and the measurement point and the inflection point are passed. Bending is performed by calculating the target pushing amount (St _T ) so that the inclination (f1) of the straight line and the inclination (f2) of the straight line passing through the inflection point and the processing point satisfy a predetermined relationship. Is the gist.

The bending method using the press brake according to claim 2 is:
When the target push-in amount (St _T ) is the width (V) of the V groove (20) of the lower mold (18) and the plate thickness (t) of the workpiece (W), the measurement point and the inflection The gist is that the slope (f1) of the straight line passing through the point and the slope (f2) of the straight line passing through the inflection point and the machining point are calculated so as to satisfy the relationship of the following formula (f).

The bending method using the press brake according to claim 3 is:
The bend factor (A ₁ ) determined based on the machining conditions of the workpiece (W) and the finished angle (θ) of the workpiece (W) is obtained based on the set finished angle (θ ₁ ), and the following equation (e) Then, the set push amount (St ₁ ) is calculated under the conditions of A = A ₁ and θ = θ ₁ and the workpiece (W) is bent at the set push amount (St ₁ ), and then the set push amount (St ₁ ) Calculate the corrected bend factor (A ′) from the measured finish angle (θ _M ) under the condition that θ = θ _M in the following equation (e),
Based on the specific indentation amount (St _F ) calculated from the corrected bend factor (A ′) and the specific finishing angle (θ _F ) under the conditions of A = A ′ and θ = θ _F in the following equation (e): The gist is that the slope (f1) of the straight line passing through the measurement point and the inflection point is calculated.

The bending method using the press brake according to claim 4 is:
The bend factor (A ₁ ) is calculated based on the following equation (i) under the condition of θ = θ ₁ .

The bending method using the press brake according to claim 5 is:
In the following equation (m), the device set deflection amount (λ ₁ ) obtained under the conditions of θ = θ ₁ and St = St ₁ is added to the set push amount (St ₁ ), and the corrected set push amount (St ₁ ′). Measure the bending angle of the workpiece (W) after bending with the measured finished angle (θ _M ),
Formula (m) in the _{θ = θ T, St = St} T and the apparatus deflection amount obtained under the following conditions (lambda _T) corrected target pressing amount obtained by adding to the target pressing amount (St _T) a (St T _') The gist is that the workpiece (W) is bent at.

The bending method using the press brake according to claim 6 is:
When bending a workpiece using an upper die whose tip is formed in an arc shape,
In the following equation (q), the indentation amount error (D ₁ ) obtained under the condition that θ = θ ₁ is subtracted from the set indentation amount (St ₁ ), and the bending amount is set by the R bending correction setting indentation amount (St ₁ ″). The bending angle of the workpiece after bending is measured as the actually measured finish angle (θ _M ),
In the following equation (q), the workpiece is calculated with an R bending corrected target push amount (St _T ″) obtained by subtracting the push amount error (D _T ) obtained under the condition of θ = θ _T from the target push amount (St _T ). The main point is that the bending process is performed.

The bending method using the press brake according to claim 7 is:
The gist is that the set finishing angle (θ ₁ ) is set in a range of 0.1 ° ≦ θ ₁ −θ _F ≦ 7 °.

In order to overcome the above-mentioned problems and achieve the intended purpose, a folding system using a press brake according to claim 8 of the present application is provided.
An upper mold (26), a lower mold (18) in which a V-groove (20) disposed opposite to the upper mold (26) is formed, and an upper mold (26 in the V-groove (20)) ) And a mold driving means (28) for driving the upper mold (26) or the lower mold (18) so as to push the upper mold (26), and the upper mold (26) by driving the mold driving means (28). ) Is pushed into the V-groove (20), the work (W) is brought into contact with the inclined surface of the V-groove (20), and the finished angle of the work (W) is equal to the predetermined target finish angle (θ _T ). A bending system using a press brake that performs bending so that
An input means (32) for inputting a machining condition of the workpiece (W) and a target finish angle (θ _T ) of the workpiece (W) and an actual measured finish angle (θ _M ) of the measured workpiece (W); ,
Based on the machining conditions and the target finish angle (θ _T ) of the workpiece (W) input to the input means (32), the load is unloaded when the workpiece (W) comes into contact with the inclined surface of the V-groove (20). Setting means (34) for setting the set finishing angle (θ ₁ ) of the workpiece (W) under a condition that is larger than the specific finishing angle (θ _F ) of the workpiece (W);
A set push amount (St ₁ ) that is the push amount of the upper die (26) corresponding to the set finishing angle (θ ₁ ) set by the setting means (34) is calculated, and the set push amount (St ₁ ) And an actual finishing angle (θ _M ) input to the input means (32), and a target pushing amount (St _T ) that is a pushing amount of the upper mold (26) corresponding to the target finishing angle (θ _T ). ) Calculating means (36),
The mold driving means so that the upper mold (26) is pushed into the V groove (20) according to the set pushing amount (St ₁ ) or the target pushing amount (St _T ) calculated by the calculating means (36). Drive control means (40) for controlling the drive,
The calculating means (36) is configured to measure the measured finish angle (θ _M ) in a St-θ graph representing the relationship between the pushing amount (St) of the upper die (26) and the finish angle (θ) of the workpiece (W). And a point determined by the set push amount (St ₁ ) as a measurement point, a specific push amount that is a push amount of the upper die (26) corresponding to the specific finish angle (θ _F ) and the specific finish angle (θ _F ) (St _F) and an inflection point a point defined by the target pushing amount of the push-in amount of the target finish angle upper die corresponding to (θ _{T) (26)} to (St _T) in the case of the processing point The target indentation amount (St _{T T} ) so that the slope (f1) of the straight line passing through the measurement point and the inflection point and the slope (f2) of the straight line passing through the inflection point and the machining point satisfy a predetermined relationship. ) Is calculated,
Said drive control means (40) is folded for the first time by controlling the driving of the said mold driving means (28) bending is performed according to the settings pushing amount calculated by said calculating means (36) (St _1), Calculated by the calculating means (36) based on the actually measured finishing angle (θ _M ) and the set push-in amount (St ₁ ) of the workpiece (W) input to the input means (32) after the first bending process. The gist is that the second and subsequent bending processes are executed by the drive control means (40) drivingly controlling the mold drive means (28) in accordance with the target pushing amount (St _T ).

The bending processing system by the press brake according to claim 9 of the present application is:
When the calculation means (36) uses the width (V) of the V-groove (20) of the lower mold (18) and the thickness (t) of the workpiece (W), the measurement in the St-θ graph is performed. The target pushing amount so that the relationship between the slope (f1) of the straight line passing through the point and the inflection point and the slope (f2) of the straight line passing through the inflection point and the machining point satisfies the relationship of the following formula (f): The gist is that it is set to calculate (St _T ).

The bending processing system by the press brake according to claim 10 of the present application is:
Storage means for storing a bend factor data table representing a correspondence relationship between the finish angle (θ) of the work (W) and the bend factor (A) calculated from the machining conditions and the finish angle (θ) of the work (W) (38)
The calculating means (36)
The bend factor (A ₁ ) corresponding to the set finishing angle (θ ₁ ) set by the setting means (34) is stored based on the machining conditions of the workpiece (W) input to the input means (32). It is obtained from the bend factor data table stored in the means (38), and is set so as to calculate the set push amount (St ₁ ) under the condition that A = A ₁ and θ = θ ₁ in the following equation (e). And
Found finishing angle (theta _M) and the set pressing amount (St ₁₎ fixed in the conditions as theta = theta _M in the formula (e) below from the bend factor of the input work (W) to said input means (32) ( A ′) is calculated backward, and the specific indentation amount (A = A ′, θ = θ _F in the following equation (e) is calculated from the corrected bend factor (A ′) and the specific finish angle (θ _F ) ( Based on St _F ), the gist is set to calculate the slope (f1) of the straight line passing through the measurement point and the inflection point.

The bending system by the press brake according to claim 11 of the present application is:
The calculating means (36)
The bend factor (A ₁ ) corresponding to the set finishing angle (θ ₁ ) set by the setting means (34) is calculated under the condition that θ = θ ₁ in the following formula (i), and the following formula In (e), the setting push amount (St ₁ ) is set to be calculated under the conditions of A = A ₁ and θ = θ ₁ .
Found finishing angle (theta _M) and the set pressing amount (St ₁₎ fixed in the conditions as theta = theta _M in the formula (e) below from the bend factor of the input work (W) to said input means (32) ( A ′) is calculated backward, and the specific indentation amount (A = A ′, θ = θ _F in the following equation (e) is calculated from the corrected bend factor (A ′) and the specific finish angle (θ _F ) ( Based on St _F ), the gist is set to calculate the slope (f1) of the straight line passing through the measurement point and the inflection point.

The bending system by the press brake according to claim 12 of the present application is:
The calculating means (36)
Correction setting push amount obtained by adding the setting push-in amount that equation in _{(m) θ = θ 1,} St = St 1 and the conditions in the sought device Deflection (lambda ₁₎ below (St ₁₎ a (St 1 _') The correction target is set to be calculated, and the device deflection amount (λ _T ) obtained under the condition of θ = θ _T and St = St _{T in the} equation (m) is added to the target pushing amount (St _T ). It is set to calculate the indentation amount (St _T ')
It said correction setting pushing amount calculated by said calculating means (36) (St 1 _') 1 st order diffracted by said drive control means (40) drives and controls the die driving means (28) in accordance with bending is performed Then, the drive control means (40) drives and controls the mold drive means (28) according to the corrected target pushing amount (St _T ') calculated by the calculation means (36), so that the second and subsequent bendings are performed. The gist is that the processing is performed.

The bending system by the press brake according to claim 13 of the present application is
The tip of the upper mold is formed in an arc shape,
The calculating means includes
The setting push amount equation given by theta = theta ₁ and the conditions in (q) pushing amount error (D ₁₎ of the following R bending correction setting pushing amount is subtracted from (St ₁₎ calculated (St 1 _'') R bending correction target push amount (St) obtained by subtracting the push amount error (D _T ) obtained under the condition that θ = θ _{T in the} equation (q) from the target push amount (St _T ) _Is set to calculate _T '')
According to the R bending correction setting push amount (St ₁ ″) calculated by the calculating unit, the drive control unit drives and controls the mold driving unit, and the first bending process is executed. The gist is that the drive control means controls the mold drive means according to the calculated R bending correction target push-in amount (St _T ″) so that the second and subsequent bending processes are executed. And

The bending system by the press brake according to claim 14 of the present application is:
The gist of the setting means (34) is to set the set finishing angle (θ ₁ ) in a range of 0.1 ° ≦ θ ₁ −θ _F ≦ 7 °.

According to the bending method and the bending processing system using the press brake according to the present invention, the workpiece is folded to a target finish angle at which the workpiece needs to be brought into contact with the inclined surface of the V groove of the lower mold during the bending process. Even when bending, the target indentation amount corresponding to the target finish angle can be calculated by bending the workpiece once, reducing the number of times the workpiece needs to be bent before the product can be manufactured. Productivity can be improved. Moreover, since it is not necessary to measure the bending angle of the workpiece during the bending process, it is not necessary to use sensors for the upper and lower molds, and general-purpose molds that are generally used can be used, so that the work shapes that can be machined It is possible to easily bend the workpiece to the target finish angle without being restricted by the above. In addition, when the inclination of the straight line passing through the measurement point and the inflection point and the inclination of the straight line passing through the inflection point and the machining point are satisfied, the workpiece is accurately obtained. Can be bent to the target finish angle.
In addition, by calculating the bend factor based on the formula (i), it is not necessary to create a database of bend factor values in advance for each machining condition of the workpiece, and the applicable range of the set finishing angle is widened and versatility is enhanced. . Furthermore, by correcting the deflection amount of the apparatus at the time of bending the workpiece, the workpiece can be bent with higher accuracy. Furthermore, when bending is performed using an upper mold having a tip formed in an arc shape, an error that separates the tip of the upper mold from the deepest part of the bent part of the workpiece is corrected. As a result, the workpiece can be bent with higher accuracy.

It is a front view which shows the press brake which concerns on the Example of this invention. It is explanatory drawing which shows the state which bends a workpiece | work with the press brake which concerns on an Example, (a) shows the state before the bending process which the upper metal mold contacted the workpiece, (b) shows an upper metal mold. A state in which the workpiece is pushed into the V groove and brought into contact with the inclined surface of the V groove of the lower mold is shown. It is a block diagram which shows the relationship between the input means of the press brake which concerns on an Example, a control apparatus, and a metal mold | die drive means. It is the graph which showed the relationship between the width / plate thickness of the V groove in the bending process of a workpiece | work, and a specific finishing angle. It is a St-θ graph showing the relationship between the pressing amount of the upper mold and the finishing angle of the workpiece, and is a schematic diagram showing the relationship between measurement points, inflection points, and machining points in workpiece bending. It is explanatory drawing which derives | leads-out the relational expression which shows the relationship between the upper and lower metal mold | dies at the time of the workpiece bending process by a press brake, and a workpiece | work. It is explanatory drawing which derives the relational expression which shows the relation between the upper and lower molds and the work at the time of work bending by press brake, (a) shows the relation between the work and the lower mold, (b) It is the figure which expanded the X part of a). It is a graph showing the relationship between a set finishing angle and a bend factor for a cold-rolled steel sheet (SPCC) in a bend factor data table stored in a storage means. It is a graph which shows the experimental result at the time of bending a workpiece | work with the width V = 8mm of V groove in the 1st experiment example. It is a graph which shows the experimental result at the time of bending a workpiece | work with the width V = 10mm of V groove in the 1st experiment example. It is a graph which shows the experimental result at the time of bending a workpiece | work with the width | variety V = 12mm of V groove in the 1st experiment example. It is a graph which shows the experimental result at the time of bending a workpiece | work with the width | variety V = 16mm of V groove in the 1st experiment example. It is a graph which shows the experimental result at the time of carrying out the bending process of the width | variety V = 12mm of V groove in the 2nd experiment example, and plate | board thickness t = 1.5mm of a workpiece | work. It is a graph which shows the experimental result at the time of carrying out the bending process of the width | variety V = 12mm of V groove in the 2nd experiment example, and plate | board thickness t = 2.0mm of a workpiece | work. It is a graph which shows the experimental result at the time of bending a workpiece | work by setting the width V = 16mm of V groove in the 2nd experiment example, and plate | board thickness t = 3.0mm of a workpiece | work. It is a graph which shows the experimental result at the time of bending a workpiece | work with the width V of a V-groove V = 12mm and the board thickness t = 1.5mm of a workpiece | work in a 3rd experiment example. It is a graph which shows the experimental result at the time of bending a workpiece | work with the width V = 16mm of V groove in the 3rd experiment example, and plate | board thickness t = 3.0mm of a workpiece | work. It is a graph which shows the experimental result at the time of carrying out the bending process of the width | variety V = 12mm of V groove in the 4th experiment example, and plate | board thickness t = 1.0mm of a workpiece | work. It is a graph which shows the experimental result at the time of carrying out the bending process of the width | variety V = 16mm of V groove in the 4th experiment example, and plate | board thickness t = 1.5mm of a workpiece | work. It is a graph which shows the experimental result at the time of bending a workpiece | work with the width V = 12mm of V-groove, and the board thickness t = 1.0mm of a workpiece | work in a 5th experiment example. It is a graph which shows the experimental result at the time of bending a workpiece | work with the width V = 16mm of V groove in the 5th experiment example, and plate | board thickness t = 1.5mm of a workpiece | work. It is a graph which shows the experimental result at the time of bending a workpiece | work with the width | variety V = 12mm of V-groove and the board thickness t = 1.0mm of a workpiece | work in a 6th experiment example. It is a graph which shows the experimental result at the time of carrying out the bending process of the width | variety V = 10mm of V groove in the 6th experiment example, and plate | board thickness t = 1.5mm of a workpiece | work. It is a graph which shows the experimental result at the time of bending a workpiece | work with the width | variety V = 12mm of V-groove and the board thickness t = 2.0mm of a workpiece | work in a 6th experiment example. It is a graph which shows the experimental result at the time of bending a workpiece | work with the width | variety V = 6mm of V-groove and the board thickness t = 1.0mm of a workpiece | work in a 7th experiment example. It is a graph which shows the experimental result at the time of bending a workpiece | work with the width | variety V = 10mm of V groove in the 7th experiment example, and plate | board thickness t = 1.5mm of a workpiece | work. It is a graph which shows the experimental result at the time of carrying out the bending process of the width | variety V = 12mm of V groove in the 7th experiment example, and plate | board thickness t = 2.0mm of a workpiece | work. It is a graph which shows the experimental result at the time of bending a workpiece | work with the width | variety V = 12mm of V-groove and the board thickness t = 1.0mm of a workpiece | work in the 8th experiment example. It is a graph which shows the experimental result at the time of bending a workpiece | work with the width | variety V = 16mm of V groove in the 8th experiment example, and plate | board thickness t = 1.5mm of a workpiece | work. It is a graph which shows the experimental result at the time of bending a workpiece | work with the width | variety V = 18mm of V-groove and the board thickness t = 2.0mm of a workpiece | work in the 8th experiment example. The horizontal axis is the finished angle (θ), and the vertical axis is the ratio of the value of the bend factor (A) at each finished angle (θ) to the value of the bend factor (A ₁₀₀ ) at the finished angle of 100 °. is there. The broken line indicates an intermediate value of A / A ₁₀₀ values at each finishing angle. Regarding cold rolled steel sheet (SPCC), the relationship between V groove width (V) / sheet thickness (t) and bend factor value (A ₁₀₀ ) / V groove width (V) at a finishing angle of 100 ° is shown. FIG. It is the graph which showed the relationship between pushing amount (St) and processing load (W). A V-groove width (V) / plate thickness (t), is a graph showing the relationship between the coefficient (k _1). In the bending process within the range of indentation amount of the upper mold (St) ≧ specific indentation amount (St _F ), the ratio between the increase amount of the indentation amount (St) and the variation amount of the processing load (W) is expressed as k _w In this case, the horizontal axis is the plate thickness (t) of the workpiece W, and the vertical axis is k _w / W _a . It is the schematic which shows the state which bent the workpiece | work using the upper metal mold | die in which the front-end | tip part was formed in circular arc shape. When bending a workpiece of aluminum (A5052P) with a tip radius R _P = 1.0 mm, V groove width V = 6 mm, and plate thickness t = 1.0 mm, the upper die is obtained by equation (n). Is a graph showing the relationship between the R-bend corrected push amount (St ″) and the finished angle (θ) and the analysis value of the R-bend corrected push amount (St ″) analyzed by the finite element analysis method. is there. Note that the relationship between the push-in amount (St) and the finished angle (θ) obtained by the equation (e) is indicated by a broken line.

  Next, the bending method and the bending processing system using the press brake according to the present invention will be described in detail with reference to the accompanying drawings by giving preferred embodiments.

  FIG. 1 is a schematic diagram illustrating a press brake 10 according to the first embodiment. The press brake 10 is provided with a lower table 16 on a bed 14 positioned at the lower part of the front surface of a pair of left and right side frames 12, 12 formed in a C shape, and a lower mold 18 is detachable on the lower table 16. A ram 22 is provided on the upper front surface of the side frames 12 and 12 so as to be movable up and down. A holder 24 is provided at a lower end portion of the ram 22 at a position facing a lower mold 18 mounted on the lower table 16, and an upper mold 26 is detachably attached to the holder 24. Also, cylinder rods of hydraulic cylinders arranged as an example of the mold drive means 28 are connected to the upper left and right ends of the ram 22 at the upper positions of the left and right side frames 12 and 12, respectively. By driving this, the ram 22 is moved up and down to move the upper mold 26 up and down. The mold driving means 28 is not limited to a hydraulic cylinder, and other conventionally known means such as a ball screw driven by a servo motor can be employed.

  As shown in FIG. 2, a V-shaped groove 20 (hereinafter referred to as a V-groove) that opens upward is formed on the upper surface of the lower mold 18 so as to extend in the width direction of the press brake 10. As the ram 22 moves downward, the upper mold 26 enters the V groove 20. Accordingly, when the ram 22 is moved downward while the work W is supported by the lower mold 18 so as to straddle the V-groove 20, the pressure applied by the upper mold 26 acts on the work W, whereby the work W is predetermined. It can be bent at an angle. The press brake 10 according to the first embodiment is of a type in which the upper die 26 moved downward is pushed into the V groove 20 of the lower die 18 to bend the workpiece W. Even if the lower die 18 is moved up and down by driving the means 28 and the upper die 26 is pushed into the V groove 20 of the lower die 18, the workpiece W can be bent similarly. . That is, when the upper mold 26 is relatively pushed into the V groove 20 of the lower mold 18 disposed opposite to the upper mold 26, any of the upper and lower upper molds 26 moves up and down. There may be.

Further, the press brake 10 is provided with a control device 30 for controlling the press brake 10, and based on the workpiece machining conditions input to the input means 32 (input terminal) connected to the control device 30. The pushing amount of the upper die 26 (the amount of downward movement of the upper die 26 after coming into contact with the workpiece W) is calculated, and the upper die 26 is pushed into the V groove 20 by the calculated pushing amount. The mold drive control means 40 provided in the control device 30 is configured to drive the mold drive means 28 so that the ram 22 moves up and down. Here, the input means 32 includes an angle (for example, 80 °, 88 °, 90 °, etc.) of the V groove 20 of the lower mold 18, a width dimension (V) of the V groove 20 of the lower mold 18, and an upper mold. Mold information such as the tip angle of the mold 26 (for example, 80 °, 88 °, 90 °, etc.) is input, and workpiece information such as the material of the workpiece W and the thickness (t) of the workpiece W is input. Is done. Further, the input means 32 receives a target finish angle of the workpiece W (hereinafter referred to as a target finish angle (θ _T )) in the final product bent by the press brake 10, and the first time. The finished angle of the workpiece W measured after the bending process (hereinafter referred to as the measured finished angle (θ _M )) is input. Based on these input values, the first bending process is performed. The pushing amount of the upper die 26 (hereinafter referred to as a set pushing amount (St ₁ )) and the pushing amount of the upper die 26 (hereinafter referred to as a target pushing amount (St _T )) during the second and subsequent bending processes. The control device 30 is configured to calculate. In the press brake 10 according to the first embodiment, the mold information related to the upper and lower molds 18 and 26 is preset for each type of the molds 18 and 26 in the storage unit 38 included in the control device 30. Corresponding mold information is automatically acquired by selecting the molds 18 and 26 used for the bending process on the input means 32.

Next, a method for calculating the set push amount (St ₁ ) and the target push amount (St _T ) in the control device 30 will be described. The control device 30 determines the finishing angle of the workpiece W that is bent in the first bending process based on the input values (the processing conditions and the target finishing angle (θ _T ) of the workpiece W) input to the input means 32. A setting means 34 for setting a set finishing angle (θ ₁ ) is provided, and a setting that is a pressing amount of the upper mold 26 based on the setting finishing angle (θ ₁ ) set by the setting means 34. A push amount (St ₁ ) is calculated, and an upper metal plate corresponding to the target finish angle (θ _T ) based on the set push amount (St ₁ ) and the actually measured finish angle (θ _M ) input to the input means 32. A calculating means 36 for calculating the pressing amount of the mold 26 (that is, the target pressing amount (St _T )) is provided (see FIG. 3). That is, in the press brake 10 according to the first embodiment, the target of the upper die 26 corresponding to the final target angle (θ _T ) of the target workpiece W is obtained by performing the first workpiece bending process. The pushing amount (St _T ) is calculated, and the workpiece W bent at the target finish angle (θ _T ) is manufactured by bending the workpiece W for the second and subsequent times.

Here, the setting means 34 is referred to as a finished angle of the workpiece W when the workpiece W is unloaded when the workpiece W comes into contact with the inclined surface of the V groove 20 of the lower mold 18 (hereinafter referred to as a specific finished angle (θ _F )). ) Is set so that the set finishing angle (θ ₁ ) is set under a condition that becomes larger than. It has been experimentally confirmed that the specific finishing angle (θ _F ) is determined depending on the thickness (t) of the workpiece W and the width dimension (V) of the V groove 20 for each material of the workpiece W, The value of V / t and the specific finishing angle (θ _F ) have the relationship shown in FIG. Therefore, an inflection point expression represented by the following expression (a) obtained by approximating each curve shown in FIG. 4 with a quadratic function is set in the setting means 34, and the workpiece W input to the input means 32 is set. The specific finishing angle (θ _F ) is calculated based on the machining conditions (specifically, the width dimension (V) of the V-groove 20, the plate thickness (t) of the workpiece W, the material of the workpiece W), and the specified The set finishing angle (θ ₁ ) is set under conditions that are larger than the finishing angle (θ _F ). Note that a, b, and c are coefficients specific to the material of the workpiece W. Table 1 shows the coefficient values for an example of the workpiece W when the angle of the V groove 20 of the lower mold 18 is 88 °. Show.

Here, in the setting means 34 of the press brake 10 according to the _first embodiment, the set finishing angle (θ ₁ ) is set in a range of 0.1 ° ≦ θ ₁ −θ _F ≦ 7 °. In the St-θ graph (see FIG. 5) showing the relationship between the pressing amount (St) of the upper die 26 and the finishing angle (θ) of the workpiece W when the workpiece W is bent, the inflection point is described later. The calculation means 36 calculates the target finish angle (θ _T ) using changes in the slopes f1 and f2 of the straight lines before and after (a point specified by the specific push amount (St _F ) and the specific finish angle (θ _F )). However, because of the characteristics of the bending process, the relationship between the pushing amount (St) of the upper die 26 and the finished angle (θ) of the workpiece W is not represented by a complete linear function. The set finishing angle (θ ₁ ) is set in the range of 0.1 ° ≦ θ ₁ −θ _F ≦ 7 °, and the point specified by the measurement point (setting push amount (St ₁ ) and actual finishing angle (θ _M )) ) by the close as possible to the inflection point, calculate child target pushing amount (St ₁₎ with high precision It becomes possible. On the other hand, when the set finishing angle (θ ₁ ) is set in the range of θ ₁ −θ _F <0.1 °, the workpiece W becomes V at the time of bending due to the dimensional error of the thickness (t) of the workpiece W. There is a possibility that the bending characteristics of the workpiece will change greatly due to contact with the inclined surface of the groove 20, and it is preferable to satisfy 0.1 ° ≦ θ ₁ −θ _F. If high-precision bending is not required, the set finishing angle (θ ₁ ) may be set so that the value of θ ₁ −θ _F falls outside the above range.

When the setting finish angle (θ ₁ ) is set by the setting means 34, the set push-in amount (St ₁ ) is calculated by the calculation means 36 based on the setting finish angle (θ ₁ ). Here, the set push amount (St ₁ ) is determined by the finish angle of the work W bent and unloaded in the air bend state from the geometric shape of the work W bending, and the push amount of the upper die 26. It is calculated from the relational expression showing

  Therefore, the derivation of the relational expression showing the relationship between the finished angle of the work W bent and unloaded in the air bend state and the pushing amount of the upper mold 26 will be described. First, as shown in FIG. 6, the following equation (b) is geometrically determined from the bent state of the work W with an air bend.

  Further, when attention is paid to the triangular portion shown by oblique lines in FIG. 7, the following equations (c) and (d) are obtained. Note that the bending angle (θ) in the expressions (b) to (d) is the sandwiching angle.

  Since FIG. 7 has a relationship of α = (180−θ) / 2, assuming that the inner radius R of the work bent portion and the inner arc length A of the work bent portion, the relationship of A = 2παR / 180 is obtained. The following formula (e) can be obtained by combining the formulas (b) to (d) by using the above. In FIG. 7, the upper mold 26 for pressurizing the workpiece W is omitted. Note that, when the workpiece W is unloaded after the upper die 26 is pressed by applying the pressing force, a springback occurs. Therefore, the amount of bending when the workpiece W is plastically deformed to the center is determined by the elastic recovery of the workpiece W. The correction amount δ is calculated by calculation of the bending of material mechanics, and is subtracted from the pushing amount of the upper die 26. In this way, by correcting the elastic recovery correction amount δ, the bending angle (θ) in the equation (e) can be regarded as a finished angle.

  The arc length A means the length of the arc portion of the workpiece bending portion in the mathematical formula, but the bent portion of the workpiece W that is actually bent is not a complete arc. , A is referred to as “bend factor (A)”.

The bend factor (A) is the processing conditions of the workpiece W (specifically, the angle (φ) of the V groove 20, the width dimension (V) of the V groove 20, the material of the workpiece W, the plate thickness (t) of the workpiece W) ) And a value determined based on the relationship with the finished angle of the workpiece W during bending. Therefore, in the first embodiment, a bend factor data table indicating the relationship between the finished angle (θ) of the workpiece W obtained by the finite element analysis method and the bend factor (A) is stored in the storage unit 38 for each machining condition of the workpiece W. It is remembered. Table 2 shows an example of the bend factor data table stored in the storage means 38, and FIG. 8 shows an example of the cold rolled steel sheet (SPCC) as a graph in the bend factor data table stored in the storage means 38. Is. That is, the calculation means 36 calculates the bend factor (A ₁ ) corresponding to the set finishing angle (θ ₁ ) set by the setting means 34 based on the machining conditions of the workpiece W input to the input means 32. Obtained from the bend factor data table stored in the storage means 38. In the above formula (e), the set push amount (St ₁ ) is calculated under the conditions of A = A ₁ and θ = θ ₁ .

Further, when the measured finishing angle (θ _M ) measured from the workpiece W after the first bending of the workpiece is input to the input unit 32, the calculating unit 36 sets the set push-in amount (St ₁ ) and measured. Based on the finishing angle (θ _M ), the target pressing amount (St _T ) that is the pressing amount of the upper mold 26 corresponding to the target finishing angle (θ _T ) is set. Specifically, the calculation means 36 is a St-θ graph representing the relationship between the pushing amount (St) of the upper die 26 and the finish angle (θ) of the work W, and the measured finish angle (θ _M ) and Using the point determined by the set push amount (St ₁ ) as a measurement point, the specific push amount (St _F ) that becomes the push amount of the upper mold 26 corresponding to the specific finish angle (θ _F ) and the specific finish angle (θ _F ) ) and inflection points the point defined by, when said target finishing angle (theta _T) target pushing amount of the push-in amount of the upper die 26 corresponding to the (St _T) was processed point, surveying a fixed point and The target indentation amount (St _T ) is calculated so that the inclination (f1) of the straight line passing through the inflection point and the inclination (f2) of the straight line passing through the inflection point and the machining point satisfy a predetermined relationship. Is set.

Specifically, in the calculation means 36, θ = θ _M in the above equation (e) from the actually measured finishing angle (θ _M ) and the set push amount (St ₁ ) of the workpiece W input to the input means 32. The corrected bend factor (A ′) is calculated backward under the condition of St = St ₁ and A = A ′, θ = in the above equation (e) from the corrected bend factor (A ′) and the specific finished angle (θ _F ). Based on the specific indentation amount (St _F ) calculated under the condition of θ _F , the measurement point and the inflection point in the St-θ graph are specified, and the slope of the straight line passing through the measurement point and the inflection point ( f1) is calculated.

The calculating means 36 calculates the measurement point and the inflection point in the St-θ graph when the width dimension (V) of the V groove 20 of the lower mold 18 and the plate thickness (t) of the workpiece W are set. The relationship between the inclination (f1) of the straight line passing through and the inclination (f2) of the straight line passing through the inflection point and the machining point passes through the inflection point and the machining point so as to satisfy the relationship of the following formula (f). The inclination (f2) of the straight line is determined, and corresponds to the target finish angle (θ _T ) of the workpiece W input to the input means 32 on the straight line of the inclination (f2) passing through the inflection point and the machining point. The pushing amount is calculated as a target pushing amount (St _T ). Then, when the target pushing amount (St _T ) is calculated by the calculating means 36, the mold of the control device 30 is pushed so that the upper mold 26 is pushed into the V groove 20 by the calculated target pushing amount (St _T ). The mold drive control means 40 controls the mold drive means 28 to execute the second and subsequent bending processes.

When the target pushing amount (St _T ) is calculated by the calculating means 36, the control device 30 moves the die 30 so that the upper die 26 is pushed into the V groove 20 by the calculated target pushing amount (St _T ). The drive means 28 is driven and controlled, and the second and subsequent bending processes are executed. Thereby, the final finished angle (θ _L ) after being bent by the second and subsequent bending processes is in the range of −0.25 ° ≦ θ _L −θ _T ≦ 0.25 °. Can be obtained. That is, when the upper mold 26 is relatively pushed into the V groove 20 of the lower mold 18, the target finish angle at which the work W needs to be brought into contact with the inclined surface of the V groove 20 of the lower mold 18. even in the case of bending the workpiece W to (θ _T), is calculated once the target pressing amount corresponding to the target finish angle (theta _T) by performing a bending of the workpiece W to (St _T) Thus, the number of times the workpiece W is bent before the product can be manufactured can be greatly reduced, and productivity can be improved. In addition, since it is not necessary to measure the bending angle of the workpiece W during the bending process, a special mold having a sensor or the like is not required for the upper and lower molds 18 and 26, and the general-purpose general-purpose used. Since a die can be adopted, the workpiece W can be easily bent at the target finish angle (θ _T ) without being restricted by the shape of the workable workpiece.

[Experimental example]
Next, an experimental example in which the workpiece W is bent using the bending method and the bending system using the press brake 10 according to the first embodiment described above will be described. In this experimental example, the input means 32 includes an angle (φ) of the V groove 20 of the lower mold 18 of 88 °, a tip angle of the upper mold 26 of 88 °, and a target finish angle (θ _T ) of the workpiece W. The workpiece W was bent under the input of 90 °. Incidentally, in the vertical axis in FIGS. 9 to 30, to view the dashed line at the position of 90 ± 0.25 °, if there is data between the chain line the one-dot, -0.25 ° ≦ θ _L -θ _T It represents that the bending work of the work W with high accuracy satisfying ≦ 0.25 ° is performed.

(First experiment example)
In the first experimental example, a workpiece W in which aluminum (A5052P) is formed with a plate thickness (t) = 1.5 mm is used. The lower mold 18 was bent. In this first experimental example, (f1 / f2) × (V / t) = 5.0 in the above formula (f), and θ ₁ −θ _F = 1.5 °. The experimental results are shown in FIGS.

In the first test when the width dimension (V) of the V groove 20 of the lower mold 18 is 8 mm, the specific finish angle (θ _F ) calculated from the above formula (a) = 90.48 ° is shown in Table 3. As shown in the figure, a set finishing angle (θ ₁ ) = 91.98 ° and a set indentation amount (St ₁ ) = 3.152 mm were obtained. Then, from the first bending of the workpiece based on the set push amount (St ₁ ) = 3.152 mm, the actually measured finished angle (θ _M ) = 91.43 °, the specific push amount (St _F ) = 3.190 mm, The target pushing amount (St _T ) = 3.212 mm was obtained. Then, when the second workpiece bending process was performed based on the target pushing amount (St _T ) = 3.212 mm, θ _L −θ _T = 0 was obtained. Furthermore, in the same second test, θ _L −θ _T = −0.02 °, and in the third test, θ _L −θ _T = −0.03 °. In addition, the pushing amount in Table 3 is a dimension in which the upper die 26 is actually pushed into the V groove 20 in the bending process, and the same applies to Tables 4 to 10 below.

In the first test when the width dimension (V) of the V groove 20 of the lower mold 18 is set to 10 mm, from the specific finish angle (θ _F ) = 91.10 ° calculated from the above formula (a), As shown in Table 3, the set finishing angle (θ ₁ ) = 92.60 ° and the set indentation amount (St ₁ ) = 4.093 mm were obtained. From the first workpiece bending process based on the set push amount (St ₁ ) = 4.093 mm, the actually measured finished angle (θ _M ) = 92.58 °, the specific push amount (St _F ) = 4.172 mm, the target push The quantity (St _T ) = 4.231 mm was obtained. Then, when the second workpiece bending process was performed based on this target indentation amount (St _T ) = 4.231 mm, θ _L −θ _T = 0 ° was obtained. Further, in the same second test, θ _L −θ _T = −0.02 °, and in the third test, θ _L −θ _T = −0.03 °.

Furthermore, in the first test when the width dimension (V) of the V groove 20 of the lower mold 18 is set to 12 mm, from the specific finish angle (θ _F ) = 91.58 ° calculated from the above formula (a), As shown in Table 3, the set finishing angle (θ ₁ ) = 93.08 ° and the set indentation amount (St ₁ ) = 5.039 mm were obtained. From the first bending of the workpiece based on the set push amount (St ₁ ) = 5.039 mm, the actually measured finished angle (θ _M ) = 92.72 °, the specific push amount (St _F ) = 5.116 mm, the target push The quantity (St _T ) = 5.202 mm was obtained. Then, when the second workpiece bending process was performed based on this target indentation amount (St _T ) = 5.202 mm, θ _L −θ _T = + 0.17 °. Further, in the same second test, θ _L −θ _T = + 0.08 °, and in the third test, θ _L −θ _T = + 0.05 °.

In the first test when the width dimension (V) of the V groove 20 of the lower mold 18 is set to 16 mm, from the specific finish angle (θ _F ) = 92.10 ° calculated from the above formula (a), As shown in Table 3, the set finishing angle (θ ₁ ) = 93.60 ° and the set indentation amount (St ₁ ) = 6.938 mm were obtained. From the first workpiece bending process based on this set indentation amount (St ₁ ) = 6.938 mm, the actually measured finished angle (θ _M ) = 94.00 °, the specific indentation amount (St _F ) = 7.130 mm, the target Indentation amount (St _T ) = 7.252 mm was obtained. Then, when the second workpiece bending process was performed based on the target push amount (St _T ) = 7.252 mm, θ _L −θ _T = −0.03 °. Further, in the same second test, θ _L −θ _T = −0.17 °, and in the third test, θ _L −θ _T = −0.02 °.

That is, as shown in FIGS. 9 to 12, the target push amount (St _T ) corresponding to the target finish angle (θ _T ) can be calculated by performing the first bending of the workpiece W, In the second and subsequent work bending processes, high-precision bending is performed by pressing the upper mold 26 into the V-groove 20 based on the target pressing amount (St _T ).

(Example 2)
In the second experimental example, the width dimension (V) of the V-groove 20 (V) = 12 mm, V for a workpiece W in which aluminum (A5052P) is formed to a predetermined plate thickness (t) = 1.5 mm, 2.0 mm, and 3.0 mm. Bending was performed using a lower mold 18 having a thickness of 16 mm. In this experimental example, in the above formula (f), (f1 / f2) × (V / t) = 4.5 and θ ₁ −θ _F = 1.5 °. The experimental results are shown in FIGS.

In the case where the workpiece thickness (t) = 1.5 mm and the width dimension (V) of the V groove 20 of the lower mold 18 = 12 mm, the specific finishing angle (θ _F ) calculated from the above formula (a) = From 91.58 °, as shown in Table 4, the set finishing angle (θ ₁ ) = 93.08 ° and the set indentation amount (St ₁ ) = 5.039 mm were obtained, and the result of the first workpiece bending process The actually measured finished angle (θ _M ) = 92.72 °, the specific pushing amount (St _F ) = 5.115 mm, and the target pushing amount (St _T ) = 5.177 mm were obtained. Then, when the second workpiece bending process was performed based on the target push amount (St _T ) = 5.177 mm, θ _L −θ _T = + 0.23 °. Further, in the first test in the case where the workpiece thickness (t) = 2.0 mm and the width dimension (V) of the V groove 20 of the lower die 18 = 12 mm, as shown in Table 4, a specific finish angle (θ _F ) = 90.81 °, setting finishing angle (θ ₁ ) = 92.31 ° and setting indentation amount (St ₁ ) = 4.833 mm are obtained. As a result of the first work bending, the actually measured finish is obtained. An angle (θ _M ) = 92.10 °, a specific pushing amount (St _F ) = 4.911 mm, and a target pushing amount (St _T ) = 4.948 mm were obtained. Then, when the second bending process was performed under the condition of this target indentation amount (St _T ) = 4.948 mm, θ _L −θ _T = + 0.08 °, and in the same second test, , Θ _L −θ _T = + 0.05 °. Further, in the first test in the case where the workpiece thickness (t) = 3.0 mm and the width dimension (V) of the V groove 20 of the lower mold 18 = 16 mm, as shown in Table 4, a specific finish angle (θ _F ) = 90.48 °, setting finish angle (θ ₁ ) = 91.98 °, setting indentation amount (St ₁ ) = 6.295 mm are obtained, and as a result of the first work bending process, the measured finish is obtained. An angle (θ _M ) = 92.18 °, a specific pushing amount (St _F ) = 6.433 mm, and a target pushing amount (St _T ) = 6.466 mm were obtained. Then, when the second workpiece bending process was performed under the condition of this target indentation amount (St _T ) = 6.466 mm, θ _L −θ _T = + 0.08 °, and the same second test was conducted. Then, θ _L −θ _T = + 0.12 °.

That is, as shown in FIGS. 13 to 15, by setting (f1 / f2) × (V / t) = 4.5, by performing the first bending work W, the target finish angle ( The target push amount (St _T ) corresponding to θ _T ) can be calculated. In the second and subsequent workpiece bending processes, the upper die 26 is placed in the V groove 20 based on the target push amount (St _T ). High-precision bending is performed by pushing into the.

(Third experimental example)
In the third experimental example, the width dimension (V) of the V groove 20 (V) = 12 mm and V = 16 mm for a workpiece W in which aluminum (A5052P) is formed to a predetermined plate thickness (t) = 1.5 mm and 3.0 mm. Bending was performed using the lower mold 18. In this experimental example, in the above formula (f), (f1 / f2) × (V / t) = 6.5 and θ ₁ −θ _F = 1.5 °. The experimental results are shown in FIGS.

In the first test when the workpiece thickness (t) = 1.5 mm and the width dimension (V) of the V groove 20 of the lower mold 18 = 12 mm, the specific finishing angle calculated from the above formula (a) ( from θ _F) = 91.58 °, set finishing angle as shown in Table _{5 (θ 1) = 93.08 °} , set pressing amount (St ₁₎ = 5.039mm are obtained, the first workpiece folding As a result of bending, the actually measured finished angle (θ _M ) = 92.58 °, the specific indentation amount (St _F ) = 5.106 mm, and the target indentation amount (St _T ) = 5.196 mm were obtained. Then, when the second workpiece bending process was performed under the condition of this target indentation amount (St _T ) = 5.196 mm, θ _L −θ _T = −0.22 °, which was the same as the second performed. In the test, θ _L −θ _T = −0.18 °. In the first test in which the workpiece thickness (t) = 3.0 mm and the width dimension (V) of the V groove 20 of the lower mold 18 = 16 mm, the specific finish calculated from the above formula (a) is used. From the angle (θ _F ) = 90.48 °, the set finished angle (θ ₁ ) = 91.98 ° and the set indentation amount (St ₁ ) = 6.295 mm are obtained. As a result of the first bending process, The actually measured finished angle (θ _M ) = 92.18 °, the specific pushing amount (St _F ) = 6.433 mm, and the target pushing amount (St _T ) = 6.481 mm were obtained. Then, when the second workpiece bending process was performed under the condition of this target indentation amount (St _T ) = 6.481 mm, θ _L −θ _T = −0.17 °, which was the same as the second performed. In the test, θ _L −θ _T = −0.02 °.

Thus, as shown in FIGS. 16 to 17, by setting (f1 / f2) × (V / t) = 6.5, the target finish is achieved by performing the first bending work W. The target push amount (St _T ) corresponding to the angle (θ _T ) can be calculated. In the second and subsequent workpiece bending processes, the upper die 26 is moved to the V-groove based on the target push amount (St _T ). By being pushed into 20, a highly accurate bending process is performed. That is, from the first experimental example to the third experimental example, when the value of (f1 / f2) × (V / t) satisfies the relationship of the formula (f), It becomes possible to obtain the workpiece W bent with high accuracy in the range of 0.25 ° ≦ θ _L −θ _T ≦ 0.25 °.

(Example 4)
In the fourth experimental example, the width dimension (V) of the V groove 20 (V) = 12 mm and V = 16 mm for a workpiece W in which aluminum (A5052P) is formed to a predetermined plate thickness (t) = 1.0 mm and 1.5 mm. Bending was performed using the lower mold 18. In this experimental example, (f1 / f2) × (V / t) = 3.0 in the above formula (f), and θ ₁ −θ _F = 1.5 °. The experimental results are shown in FIGS.

In the first test where the workpiece thickness (t) = 1.0 mm and the width dimension (V) of the V groove 20 of the lower mold 18 = 12 mm, the specific finishing angle calculated from the above formula (a) ( From θ _F ) = 92.15 °, a set finishing angle (θ ₁ ) = 93.65 ° and a set indentation amount (St ₁ ) = 5.297 mm are obtained. As a result of the first bending, the actually measured finish is obtained. An angle (θ _M ) = 93.70 °, a specific pushing amount (St _F ) = 5.413 mm, and a target pushing amount (St _T ) = 5.456 mm were obtained. Then, when the second bending process was performed under the condition of this target indentation amount (St _T ) = 5.456 mm, θ _L −θ _T = + 0.98 °, and in the same second test, , Θ _L −θ _T = + 1.08 °. In the first test when the workpiece thickness (t) = 1.5 mm and the width dimension (V) of the V groove 20 of the lower mold 18 is 16 mm, the specific finish calculated from the above formula (a) is used. From the angle (θ _F ) = 92.10 °, the set finished angle (θ ₁ ) = 93.60 ° and the set push-in amount (St ₁ ) = 6.937 mm are obtained, and the result of the first workpiece bending process The actually measured finished angle (θ _M ) = 93.75 °, the specific pushing amount (St _F ) = 7.103 mm, and the target pushing amount (St _T ) = 7.169 mm were obtained. Then, when the second work bending process was performed under the condition of this target indentation amount (St _T ) = 7.169 mm, θ _L −θ _T = + 1.52 °, and the same second test was conducted. Then, θ _L −θ _T = + 1.12 °.

  That is, when (f1 / f2) × (V / t) = 3.0, the accuracy of the finished angle of the bent workpiece W is lower than in the first to third experimental examples, and 4 It has been experimentally revealed that it is preferable to perform .5 ≦ (f1 / f2) × (V / t) for highly accurate bending.

(Fifth experimental example)
In the fifth experimental example, the width dimension (V) of the V groove 20 (V) = 12 mm and V = 16 mm for a workpiece W in which aluminum (A5052P) is formed to a predetermined plate thickness (t) = 1.0 mm and 1.5 mm. Bending was performed using the lower mold 18. In this experimental example, in the above formula (f), (f1 / f2) × (V / t) = 8.0 and θ ₁ −θ _F = 1.5 °. The experimental results are shown in FIGS.

In the case where the plate thickness (t) of the workpiece is 1.0 mm and the width dimension (V) of the V groove 20 of the lower mold 18 is 12 mm, the specific finishing angle (θ _F ) calculated from the above formula (a) = 92 From 15 °, the set finishing angle (θ ₁ ) = 93.65 ° and the set indentation amount (St ₁ ) = 5.297 mm are obtained. As a result of the first work bending, the actually measured finishing angle (θ _M ) = 93.70 °, specific indentation amount (St _F ) = 5.413 mm, and target indentation amount (St _T ) = 5.526 mm. Then, when the second workpiece bending process was performed under the condition of this target indentation amount (St _T ) = 5.526 mm, θ _L −θ _T = −1.05 °, which was the same as the second performed. In the test, θ _L −θ _T = −0.98 °. In the first test when the workpiece thickness (t) = 1.5 mm and the width dimension (V) of the V groove 20 of the lower mold 18 is 16 mm, the specific finish calculated from the above formula (a) is used. From the angle (θ _F ) = 92.10 °, the set finished angle (θ ₁ ) = 93.60 ° and the set push-in amount (St ₁ ) = 6.937 mm are obtained, and the result of the first workpiece bending process The actually measured finished angle (θ _M ) = 93.72 °, the specific pushing amount (St _F ) = 7.100 mm, and the target pushing amount (St _T ) = 7.271 mm were obtained. Then, when the second bending process was performed under the condition of this target indentation amount (St _T ) = 7.271 mm, θ _L −θ _T = −0.43 °, and the same second test was performed. Then, θ _L −θ _T = −0.75 °.

  That is, when (f1 / f2) × (V / t) = 8.0, the accuracy of the finished angle of the bent workpiece W is lower than in the first to third experimental examples, It has been experimentally found that f1 / f2) × (V / t) ≦ 6.5 is preferable for high-precision folding.

(Sixth experimental example)
In the sixth experimental example, the width dimension (V) of the V groove 20 (V) = 10 mm, V for a workpiece W in which aluminum (A5052P) is formed to have a predetermined plate thickness (t) = 1.0 mm, 1.5 mm, and 2.0 mm. Bending was performed using a lower mold 18 having a thickness of 12 mm. In this experimental example, in the above equation (f), (f1 / f2) × (V / t) = 5.0 and θ ₁ −θ _F = 0.1 °. The experimental results are shown in FIGS.

In the case where the plate thickness (t) of the workpiece is 1.0 mm and the width dimension (V) of the V groove 20 of the lower mold 18 is 12 mm, the specific finishing angle (θ _F ) calculated from the above formula (a) = 92 From 15 °, a set finishing angle (θ ₁ ) = 92.25 ° and a set indentation amount (St ₁ ) = 5.402 mm are obtained. As a result of the first work bending, the actually measured finishing angle (θ _M ) = 92.45 °, specific pushing amount (St _F ) = 5.425 mm, and target pushing amount (St _T ) = 5.503 mm. When the second bending process was performed under the condition of this target indentation amount (St _T ) = 5.503 mm, θ _L −θ _T = 0 °, and θ _L −θ was obtained in the same second test. _T = −0.02 °. Further, in the first test when the workpiece thickness (t) = 1.5 mm and the width dimension (V) of the V groove 20 of the lower mold 18 = 10 mm, the specific finish calculated from the above formula (a) is used. From the angle (θ _F ) = 91.10 °, the set finishing angle (θ ₁ ) = 91.20 ° and the set indentation amount (St ₁ ) = 4.167 mm are obtained. As a result of the first bending process, The actually measured finished angle (θ _M ) = 90.93 °, the specific pushing amount (St _F ) = 4.158 mm, and the target pushing amount (St _T ) = 4.218 mm were obtained. When the second bending process was performed under the condition of this target indentation amount (St _T ) = 4.218 mm, θ _L −θ _T = + 0.18 °. In the second test conducted in the same manner, _L −θ _T = −0.08 °. Furthermore, in the first test when the workpiece thickness (t) = 2.0 mm and the width dimension (V) of the V-groove 20 of the lower die 18 is 12 mm, the constant finish calculated from the above formula (a). From the angle (θ _F ) = 90.81 °, the set finished angle (θ ₁ ) = 90.91 ° and the set indentation amount (St ₁ ) = 4.918 mm are obtained. As a result of the first bending process, The actually measured finished angle (θ _M ) = 90.45 °, the specific pushing amount (St _F ) = 4.896 mm, and the target pushing amount (St _T ) = 4.950 mm were obtained. When the second bending process was performed under the condition of this target indentation amount (St _T ) = 4.950 mm, θ _L −θ _T = −0.02 °, and in the same second test, θ _L −θ _T = −0.08 °.

That is, as shown in FIGS. 22 to 24, the target push-in amount corresponding to the target finish angle (θ _T ) is obtained by performing the first bending of the workpiece W with θ ₁ −θ _F = 0.1 °. (St _T ) can be calculated, and in the second and subsequent workpiece bending processes, the upper mold 26 is pushed into the V-groove 20 based on the target push amount (St _T ). Bending is performed.

(Example 7)
In the seventh experimental example, the width dimension (V) of the V groove 20 (V) = 6 mm, V for a work W in which aluminum (A5052P) is formed to have a predetermined thickness (t) = 1.0 mm, 1.5 mm, and 2.0 mm. Folding was performed using the lower mold 18 with = 10 mm and V = 12 mm. In this experimental example, in the above formula (f), (f1 / f2) × (V / t) = 5.0 and θ ₁ −θ _F = 7.0 °. The experimental results are shown in FIGS.

In the case where the plate thickness (t) of the workpiece is 1.0 mm and the width dimension (V) of the V groove 20 of the lower mold 18 is 6 mm, the specific finishing angle (θ _F ) calculated from the above formula (a) = 90 .81 °, a set finishing angle (θ ₁ ) = 97.81 ° and a set indentation amount (St ₁ ) = 2.264 mm are obtained. As a result of the first bending, the actually measured finishing angle (θ _M ) is obtained. = 97.40 °, specific indentation amount (St _F ) = 2.453 mm, and target indentation amount (St _T ) = 2.479 mm. When the second bending process was performed under the condition of this target indentation amount (St _T ) = 2.479 mm, θ _L −θ _T = −0.08 °, and in the same second test, θ _L −θ _T = −0.08 °. Further, in the first test when the workpiece thickness (t) = 1.5 mm and the width dimension (V) of the V groove 20 of the lower mold 18 = 10 mm, the specific finish calculated from the above formula (a) is used. From the angle (θ _F ) = 91.10 °, the set finished angle (θ ₁ ) = 98.10 ° and the set indentation amount (St ₁ ) = 3.808 mm are obtained. As a result of the first bending process, The actually measured finished angle (θ _M ) = 98.07 °, the specific pushing amount (St _F ) = 4.171 mm, and the target pushing amount (St _T ) = 4.231 mm were obtained. Then, when the second bending process was performed under the condition of this target indentation amount (St _T ) = 4.231 mm, θ _L −θ _T = + 0.08 °, and in the same second test, , Θ _L −θ _T = + 0.10 °. Furthermore, in the first test when the workpiece thickness (t) = 2.0 mm and the width dimension (V) of the V-groove 20 of the lower mold 18 = 12 mm, the specific finish calculated from the above formula (a) is used. From the angle (θ _F ) = 90.81 °, the set finishing angle (θ ₁ ) = 97.81 ° and the set indentation amount (St ₁ ) = 4.507 mm are obtained. As a result of the first bending process, The actually measured finished angle (θ _M ) = 97.45 °, the specific pushing amount (St _F ) = 4.901 mm, and the target pushing amount (St _T ) = 4.954 mm were obtained. When the workpiece was bent for the second time under the condition of this target indentation amount (St _T ) = 4.954 mm, θ _L −θ _T = 0 °, and in the second test conducted in the same manner, θ _L −θ _T = + 0.18 °.

That is, as shown in FIGS. 25 to 27, even when the _first workpiece W is bent at θ ₁ −θ _F = 7.0 °, the target push-in corresponding to the target finish angle (θ _T ) is performed. The amount (St _T ) can be calculated. In the second and subsequent workpiece bending processes, the upper die 26 is pushed into the V-groove 20 based on the target pushing amount (St _T ). High-precision folding is performed in a range of .25 ° ≦ θ _L −θ _T ≦ 0.25 °.

(Example 8)
In the eighth experimental example, the width dimension (V) of the V-groove 20 (V) = 12 mm, V for a workpiece W in which aluminum (A5052P) is formed to a predetermined plate thickness (t) = 1.0 mm, 1.5 mm, 2.0 mm. Bending was performed using a lower mold 18 having a thickness of 16 mm and V = 18 mm. In this experimental example, (f1 / f2) × (V / t) = 5.0 and θ ₁ −θ _F = 10.0 ° in the above formula (f). The experimental results are shown in FIGS.

In the case where the plate thickness (t) of the workpiece is 1.0 mm and the width dimension (V) of the V groove 20 of the lower mold 18 is 12 mm, the specific finishing angle (θ _F ) calculated from the above formula (a) = 92 From 15 °, a set finishing angle (θ ₁ ) = 102.15 ° and a set indentation amount (St ₁ ) = 4.695 mm are obtained. As a result of the first bending, the actually measured finishing angle (θ _M ) = 101.95 °, specific indentation amount (St _F ) = 5.393 mm, and target indentation amount (St _T ) = 5.471 mm. When the second bending process was performed under the condition of this target indentation amount (St _T ) = 5.471 mm, θ _L −θ _T = + 1.10 °, and in the second test similarly performed, _L −θ _T = + 1.00 °. In the first test when the workpiece thickness (t) = 1.5 mm and the width dimension (V) of the V groove 20 of the lower mold 18 is 16 mm, the specific finish calculated from the above formula (a) is used. From the angle (θ _F ) = 92.10 °, the set finished angle (θ ₁ ) = 102.10 ° and the set indentation amount (St ₁ ) = 6.128 mm are obtained. As a result of the first bending process, The actually measured finished angle (θ _M ) = 102.22 °, the specific pushing amount (St _F ) = 7.101 mm, and the target pushing amount (St _T ) = 7.222 mm were obtained. When the second bending process was performed under the condition of this target indentation amount (St _T ) = 7.222 mm, θ _L −θ _T = + 0.38 °. In the second test conducted in the same manner, _L −θ _T = + 0.62 °. Further, in the first test in which the workpiece thickness (t) = 2.0 mm and the width dimension (V) of the V groove 20 of the lower mold 18 is 18 mm, the specific finish calculated from the above formula (a) is used. From the angle (θ _F ) = 91.84 °, the set finished angle (θ ₁ ) = 101.84 ° and the set indentation amount (St ₁ ) = 6.751 mm are obtained. As a result of the first bending process, The actually measured finished angle (θ _M ) = 101.82 °, the specific pushing amount (St _F ) = 7.801 mm, and the target pushing amount (St _T ) = 7.941 mm were obtained. Then, when the second bending process was performed under the condition of this target indentation amount (St _T ) = 7.941 mm, θ _L −θ _T = + 0.58 °, and in the same second test, , Θ _L −θ _T = + 0.63 °.

That is, when θ ₁ −θ _F = 10.0 °, the accuracy of the finished angle of the bent workpiece W is lower than that of the first to third experimental examples, and 0.1 ° ≦ θ It has been experimentally clarified that ₁₋ θ _F ≦ 7.0 ° is preferable for high-precision folding.

  Next, a bending method and a bending system using the press brake according to the second embodiment will be described. Since the configuration of the press brake according to the second embodiment is the same as that of the press brake 10 shown in the first embodiment, the same reference numerals are given and detailed description thereof is omitted.

In the first embodiment described above, the processing conditions of the workpiece W (specifically, the angle (φ) of the V groove 20, the width dimension (V) of the V groove 20, the material of the workpiece W, the plate thickness (t) of the workpiece W). A bend factor data table in which the values of the bend factors (A ₁ ) are stored in advance as a database is set for each, and the bend factor (A ₁ ) corresponding to the set finishing angle (θ ₁ ) set by the setting means 34 is input. The upper die 26 is pushed in at the first bending using the bend factor (A ₁ ) acquired based on the processing conditions of the workpiece W input to the means 32 and acquired from the bend factor data table. The set push amount (St ₁ ) is calculated. On the other hand, in the second embodiment, the bend factor (A ₁ ) corresponding to the set finishing angle (θ ₁ ) is approximately calculated by calculation, so that the labor for constructing the bend factor data table in advance is omitted. Thus, the amount of data set in the storage means 38 is reduced, and the range that can be adopted as the set finishing angle (θ ₁ ) is expanded to improve versatility.

As is apparent from the relationship between the set finishing angle (θ ₁ ) and the bend factor (A) shown in FIG. 8, the value of the bend factor (A) varies depending on the finishing angle (θ) of the workpiece W. In order to increase the accuracy of the target push amount (St _T ) calculated backward by bending, it is desirable to use a value close to the target finish angle (θ _T ) as the set finish angle (θ ₁ ). Further, the value of the bend factor (A) has a smaller fluctuation range than the change in the set finishing angle (θ ₁ ) of the workpiece W, and the set finishing angle (θ ₁ ) becomes small (that is, the target pushing amount (St _T )). It can be seen that the value becomes almost constant as the value becomes closer to. Therefore, the following equation (g) is expressed as an equation that approximates the curve shape of FIG. The value of C _t in the formula (g) is an approximate absolute value of the bend factor (A ₁ ) value corresponding to the set finishing angle (θ ₁ ) of the work W. Θ _x is a finishing angle (that is, an upper limit value of the set finishing angle) that is an upper limit at which the workpiece W can be bent using the formula (g), and θ _y is a value of the bend factor (A ₁ ). Is a reference angle (hereinafter referred to as an approximate angle) that serves as a reference for approximating.

That is, the finishing angle (θ _x ) that is the upper limit at which the workpiece W can be bent is determined in a range of θ _F <θ _x ≦ 180 °. Here, the theta _x since the upper limit that can be bending the workpiece W, it is preferable to adopt a value close to 180 °. Further, as the finishing angle (θ) of the workpiece W approaches the specific finishing angle (θ _F ), the change in the bend factor (A) greatly affects the pushing amount of the upper die 26. Therefore, in order to increase the approximation accuracy, it is preferable to set the bend factor (A ₁ ) value close to the specific finishing angle (θ _F ) as the approximate angle θ _y that serves as a reference. However, as can be seen from FIG. 31, because of the characteristics of the bending process, the bending behavior of the workpiece W changes suddenly from the vicinity where the workpiece W starts to contact the inclined surface of the V groove 20, so that the specific finishing angle (θ _F ) is obtained. It is not appropriate to use a close value as a reference for approximating the value of the bend factor (A). That is, the approximate angle (θ _y ) that approximates the value of the bend factor (A) is preferably determined within the range of θ _F <θ _y <θ _x , and more preferably 95 ° ≦ θ _y <θ _x. Range. Here, the accuracy of θ _y is improved by adopting a value close to the target finish angle (θ _T ) that is the final finish angle of the workpiece W. In the second embodiment, a case where θ _x = 170 ° θ _y = 100 ° is described, and an approximate value of the bend factor (A ₁ ) at this time is expressed as A ₁₀₀ (that is, C _t = A ₁₀₀ ). .

Here, the following equation (h) is obtained by logarithmically approximating the relationship between (V / t) and (A ₁₀₀ / V) shown in FIG. Incidentally, d in the formula (h), e is an inherent coefficient determined by the material of the workpiece W, illustrating each coefficient value of the one example of the work W in the case of the A ₁₀₀ in Table 11.

The following formula (i) can be obtained by combining the formula (g) and the formula (h). That is, the bend factor (A ₁ ) as an approximate value is calculated by setting θ = θ ₁ in the following equation (i), and from the calculated bend factor (A ₁ ) and the set finishing angle (θ ₁ ), A set push amount (St ₁ ) is calculated based on the equation (e).

Specifically, the calculation means 36 of the control device 30 provided in the press brake 10 according to the second embodiment uses the bend factor (A ₁ ) corresponding to the set finishing angle (θ ₁ ) set by the setting means 34. Is calculated under the condition that θ = θ ₁ in the equation (i), and the set push amount (St ₁ ) is calculated under the conditions where A = A ₁ and θ = θ ₁ in the equation (e). The corrected bend factor (A ′) is set under the condition that θ = θ _M in the equation (e) from the actually measured finished angle (θ _M ) and the set pushing amount (St ₁ ) of the workpiece inputted to the input means 32. ) To the specific indentation amount (St _F ) calculated from the corrected bend factor (A ′) and the specific finishing angle (θ _F ) under the condition that A = A ′ and θ = θ _F in the equation (e). Based on this, the slope (f1) of the straight line passing through the measurement point and the inflection point is calculated. Cormorant is set.

As described above, in the second embodiment, the bend factor data table in which the bend factor (A ₁ ) for each machining condition of the workpiece W is previously stored in the database is not stored in the storage unit 38, and the set finish angle (θ ₁ ) is supported. The bend factor (A ₁ ) to be calculated can be calculated. Further, when the bend factor (A ₁ ) is databased as a bend factor data table, the set finishing angle (θ ₁ ) not included in the bend factor data table cannot be used. By calculating the bend factor (A ₁ ) approximately as described above, as long as the condition “set finish angle (θ ₁ )> specific finish angle (θ _F )” is satisfied, the applicable set finish angle (θ ₁ ) The versatility is improved.

  Next, a bending method and a bending system using the press brake according to the third embodiment will be described. Since the configuration of the press brake according to the third embodiment is the same as that of the press brake 10 shown in the first embodiment, the same reference numerals are given and detailed description thereof is omitted.

When the workpiece W is bent by relatively pushing the upper die 26 into the V groove 20 of the lower die 18, the processing load (W) when the upper die 26 is pushed into the V groove 20. In response to this, “deflection” occurs in the bed 14 of the press brake 10, the upper and lower molds 18, 26, and other apparatus constituent members. Therefore, when the mold driving device 30 is driven so that the upper mold 26 is pushed into the V groove 20 with the set push amount (St ₁ ) or the target push amount (St _T ), the set push amount (St ₁ ) and the target push amount (St _T ) and the push amount by which the upper die 26 is actually pushed into the V groove 20 cause an error due to “deflection”. Therefore, in the third embodiment, the upper die 26 is relatively pushed into the V groove 20 of the lower die 18 with a pushing amount obtained by correcting the deflection on the press brake 10 side that occurs during the bending process, so that a more precise workpiece W is obtained. A bending method and a bending system using a press brake capable of performing the bending process will be described. In the following description, the deflection that occurs on the side of the press brake 10 during bending is expressed as the device deflection amount (λ).

  The amount of device deflection (λ) is the longitudinal stiffness coefficient (k) [kN / mm] of the press brake 10, and the processing load (W when the upper die 26 is relatively pushed into the V groove 20 of the lower die 18. ) [KN], it can be expressed as λ = W / k by Hooke's law. That is, the device deflection (λ) is determined by the machining load (W). The longitudinal stiffness coefficient (k) is a value specific to the press brake 10 and can be obtained from design values and experiments of the press brake 10. The longitudinal stiffness coefficient (k) of the press brake 10 used in the third embodiment is used. ) Is k = 178.57.

By the way, as shown in FIG. 33, when the workpiece W is bent in a state of air bend (that is, when the pushing amount (St) of the upper die 26 does not reach the specific pushing amount (St _F )). Indicates that the processing load (W) slightly increases or decreases slightly as the push-in amount (St) increases depending on the material of the workpiece W, while the processing load (W) becomes a substantially constant value, while the workpiece W becomes V When the workpiece W is bent while being in contact with the inclined surface of the groove 20 (that is, when the upper die 26 is pushed with a pushing amount equal to or greater than the specific pushing amount (St _F )), the pushing amount (St) It is known that the machining load (W) increases rapidly with an increase in.

Here, when bending the workpiece W with air bend, until the finish angle (θ) of the workpiece W reaches 135 °, the machining load (W) is almost constant even if the pushing amount (St) increases. No change was found by finite element analysis. Therefore, the finishing angle finishing angle of the workpiece W (theta) is the 135 ° with respect finish angle (theta _A), reference finishing angle (theta _A) as a reference push-in amount of the push-in amount of the upper die 26 comprising (St _A ) In the case of “finish angle of the workpiece W (θ) ≧ reference finish angle (θ _A )” (that is, “the push amount of the upper mold 26 (St) ≦ the reference push amount (St _A )”). The processing load (W _a ) is a known fact and can be expressed by the following formula (j). In the following description, the machining load (W _a ) when “finished angle (θ) ≧ reference finished angle (θ _A ) of the workpiece W” is referred to as a reference machining load.

Here, the relationship between the ratio (V / t) of the width (V) of the V groove 20 of the lower mold 18 and the thickness (t) of the workpiece W and the coefficient (k ₁ ) is analyzed by the finite element analysis method. The results are shown in FIG. From FIG. 34, since linear approximation can be performed in the range of 5 ≦ V / t ≦ 10, k ₁ = −0.055 × V / t + 1.753 as shown in the above formula (j).

Also, when bending in the range of “specific finish angle (θ _F ) ≦ finish angle of workpiece W (θ) ≦ reference finish angle (θ _A )” (that is, “reference push amount (St _A ) ≦ upper metal In the case of the indentation amount (St) ≦ specific indentation amount (St _F ) ”of the die 26), as described above, gradually increases from the reference processing load (W _a ) as the indentation amount (St) of the upper die 26 increases. Or gradually decrease. Here, between “specific finish angle (θ _F ) ≦ θ ≦ reference finish angle (θ _A )”, the amount of change in the processing load (W) is slight because bending is performed in an air bend state, It can be considered that the processing load (W) changes linearly. Therefore, the processing load (W) when bending in the range of “specific finishing angle (θ _F ) ≦ θ ≦ reference finishing angle (θ _A )” is the processing load at the specific finishing angle (θ _F ). When the load (W _f ) is used, it is expressed by the following equation (k). Note that k _f in the equation (k) is a specific coefficient determined by the material of the work W, and Table 12 shows coefficient values for an example of the work W.

Further, when bending is performed in the range of “finish angle (θ) ≦ specific finish angle (θ _F ) of work W” (that is, “specific push amount (St _F ) ≦ push amount (St) of upper die 26”. ”), Since the workpiece W is bent while the workpiece W is in contact with the inclined surface of the V groove 20, the processing load (St) increases as the pressing amount (St) of the upper mold 26 increases as shown in FIG. W) increases rapidly from the specific processing load (W _f ). Here, the increase of the push amount (St) and the change amount of the work load (W) in the bending process within the range of “specific push amount (St _F ) ≦ push amount (St) of the upper die 26” are expressed as k _w FIG. 35 shows the result of measuring the relationship between the plate thickness (t) of the workpiece W and k _w / W _a by simulation. We obtain an approximate expression of k _w to FIG. 35 and logarithmic approximation, represents the processing load (W) in the "finishing angle (theta) ≦ particular finishing angle of the workpiece W (θ _F)" by the following equation (l) . Note that k _a and k _b in equation (l) are specific coefficients determined by the material of the workpiece W, and Table 13 shows coefficient values for an example of the workpiece W.

  Summarizing the above, by calculating the processing load (W) according to the finished angle (θ) of the workpiece W by the following formula (m), the amount of deflection of the device at the finished angle (θ) of the workpiece W is calculated. (λ) can be obtained.

In the press brake 10 according to the third embodiment, the device deflection amount (λ ₁ ) obtained under the condition that θ = θ ₁ and St = St ₁ in the formula (m) is set as the set push amount (St ₁ ). The calculation means 36 is set so that the correction setting push amount (St ₁ ′) is calculated by addition (St ₁ ′ = St ₁ + λ ₁ ), and the correction set push amount (St ₁ ) calculated by the calculation means 36 (St ₁ ′). ₁ ), the mold drive control means 40 controls the mold drive means 28 so that the first bending process is executed. That is, the set pressing amount (St ₁₎ In the apparatus deflection amount when bending (lambda ₁₎ correction setting pushing amount obtained by correcting the (St 1 _') finishing angle of the workpiece W after bending at said actual It is measured as the finished angle (θ _M ). Similarly, the calculation means 36 adds the device deflection amount (λ _T ) obtained under the condition of θ = θ _T and St = St _T in the equation (m) to the target push amount (St _T ). The correction target push amount (St _T ′) is set to be calculated (St _T ′ = St _T + λ _T ), and the mold drive control means is set according to the corrected target push amount (St _T ′) calculated by the calculation means 36. 40 is configured to execute the second and subsequent bending processes by controlling the driving of the mold driving means 28.

That is, by driving the upper mold 26 so as to be set pressing amount unit deflection amount occurring when bending in (St ₁₎ (λ ₁₎ correction setting pushing amount obtained by correcting the (St 1 _'), the actual Since the workpiece W is bent at the set indentation amount (St ₁ ), the bending accuracy in the first bending is improved. As a result, the accuracy of the corrected bend factor (A ′) calculated based on the set push amount (St ₁ ) and the actually measured finishing angle (θ _M ) is improved, and the correction is performed based on the corrected bend factor (A ′). The processing accuracy of the second and subsequent bending processes can be increased. Also, driving the upper mold 26 to be the target push-in amount the workpiece W (St _T) occurring during the bending process in the apparatus deflection amount (lambda _T) corrected target pressing amount obtained by correcting the (St T _') Since the workpiece W is actually bent at the target push amount (St _T ), the workpiece W can be bent accurately at the target finish angle (θ _T ).

  Next, a bending method and a bending system using the press brake according to the fourth embodiment will be described. Since the configuration of the press brake according to the third embodiment is the same as that of the press brake 10 shown in the first embodiment, the same reference numerals are given and detailed description thereof is omitted.

In the fourth embodiment, description will be given of a case where the workpiece W is bent by relatively pushing the upper die 26 having a tip formed in an arc shape into the V groove 20 of the lower die 18. In the following description, it represents the arc radius of the distal end portion of the upper mold 26 as the tip radius R _P (see FIG. 36). First, when the workpiece W is bent by relatively pushing the upper die 26 having the tip formed into a square shape into the V groove 20 of the lower die 18, the workpiece W is bent. Since the state in which the corner end portion of the upper die 26 is in contact with the deepest portion CP (see FIG. 36) of the bent portion of the work W is maintained even if the upper die 26 advances, the pushing amount (St ) Will be bent as much as possible. On the other hand, when the upper mold 26 whose tip is formed in an arc shape is relatively pushed into the V groove 20 of the lower mold 18, the inner radius R of the workpiece bending portion is increased. until it coincides with the point radius R _P of the mold 26, as if tip of the corner shape of the upper mold 26, the deepest portion CP of the bent portion of the workpiece W to the distal end portion PE of the upper die 26 The bending process proceeds while contacting. On the other hand, the upper mold 26 is pushed in into the V groove 20 of the lower mold 18, the inner surface radius R of the workpiece bent portion is less tip radius R _P of the upper mold 26 (i.e., R ≦ R _P ), The bending process proceeds so that the deepest portion CP of the bent portion of the work W is separated from the front end portion PE of the upper mold 26 as shown in FIG. That is, in the region where the inner surface radius R of the workpiece bent portion is equal to or less than the tip radius R _P of the upper mold 26, the gap between the deepest portion CP of the bent portion of the distal end portion PE and the workpiece W of the upper die 26 Will be able to. Therefore, the pushing amount (St) of the upper mold 26 necessary for bending the workpiece W to a predetermined finishing angle (θ) is larger than that in the case of using the upper mold 26 having a tip formed in a square shape. In the case of using the upper mold 26 whose tip is formed in an arcuate shape, it becomes shorter.

  Here, the pushing amount (St) obtained by the above-described equation (e) is such that the tip of the upper die 26 is located at the deepest portion CP of the bent portion of the workpiece W like the upper die 26 having a square tip. The amount of pressing (St) of the upper die 26 when bending is performed under the condition where the part PE is in contact. Therefore, in the fourth embodiment, when the workpiece W is bent at a predetermined finishing angle (θ) using the upper mold 26 whose tip is formed in an arc shape, the pushing amount obtained by the above-described equation (e) is used. (St) can be corrected by the gap between the tip portion PE of the upper mold 26 and the deepest portion CP of the bent portion of the workpiece W, so that the workpiece W can be bent more precisely. A bending method and a bending system using a press brake will be described. In the following description, a value obtained by correcting the indentation amount (St) obtained by the equation (e) so as to correspond to the bending process in the upper die 26 having a circular arc shape at the tip portion is an R-bend correction indentation amount ( St ″), and the gap distance between the front end PE of the upper mold 26 and the deepest portion CP of the bent portion of the workpiece W is expressed as an indentation amount error (D).

  Here, the relationship between the indentation amount (St) obtained by the equation (e), the R-bend correction indentation amount (St ″), and the indentation amount error (D) is geometrically shown in FIG. (N).

  As shown in FIG. 36, the center point of the tip arc of the upper mold 26 is O, and the intersection of the perpendicular passing through the center point O with respect to the flat surface of the work W and the flat surface of the work W is P, From the relationship of the triangle OPQ, when the intersection point where the extension line along the flat surface of the workpiece W passing through the intersection point P intersects with the vertical line passing through the center point O of the tip arc of the upper die 26 is represented by the following equation: (o) is obtained.

  Furthermore, as shown in FIG. 36, the center point of the arc portion of the workpiece bending portion in the bent workpiece W is defined as O ′, and a perpendicular drawn from the center point O ′ to the flat plate surface of the workpiece W and the workpiece W The following formula (p) is obtained from the relationship of the triangle O′P′Q where the intersection point with the flat plate surface is P ′. As in the paragraph [0037], the inner radius of the bent part of the work is R.

Summarizing the above, the following formula (q) is obtained. That is, as shown in paragraph [0037], α = (180−θ) / 2, and as shown in equation (e), R = 180A / {(180−θ) × π} Therefore, by obtaining the bend factor (A) corresponding to the finishing angle (θ) as in the first embodiment or the second embodiment, the tip radius (R _P ) of the upper mold 26 and the finishing angle of the workpiece W ( The push-in amount error (D) according to θ) can be obtained, and by substituting it into the above-described equation (n), the upper die 26 having an arcuate tip is actually used as the V groove 20 of the lower die 18. The amount of pushing that should be pushed into the inside is determined.

Here, the plate thickness (t) is set to 1.0 mm under the condition that the tip radius (R _P ) of the upper mold 26 is 1.0 mm and the width dimension (V) of the V groove 20 of the lower mold 18 is 6 mm. When bending the formed aluminum (A5052P) workpiece W, the amount of pushing of the upper die 26 (that is, the R bending correction pushing amount (St ″)) obtained by the above-described formula (n) and the finishing angle ( The relationship with θ) is indicated by a solid line in FIG. 37, and the analysis value of the R bending correction push amount (St ″) analyzed by the finite element analysis method is plotted in the graph of FIG. From FIG. 37, the workpiece W is bent by pushing the upper die 26 into the V groove 20 of the lower die 18 with the R bending push amount (St ″) obtained by the above-described equation (n). Thus, it is found that the workpiece W can be bent with high accuracy at a predetermined finishing angle (θ). In FIG. 37, the relationship between the pushing amount (St) obtained by the equation (e) and the finishing angle (θ) is indicated by a broken line. That is, when the workpiece W is bent using the upper die 26 whose tip is formed in an arcuate shape, the push amount (St) obtained by the above-described equation (e) is expressed by the equation (q). It can be seen that the accuracy of bending the workpiece W is improved by subtracting and correcting the indentation amount error (D).

In the press brake 10 according to the fourth embodiment, the bending amount error (D ₁ ) obtained under the condition that θ = θ ₁ in the equation (q) is subtracted from the set pushing amount (St ₁ ) to perform R bending. The calculation means 36 is set so as to calculate the correction setting push amount (St ₁ ″) (St ₁ ″ = St ₁ −D ₁ ), and the R bend correction set push amount calculated by the calculation means 36. According to (St ₁ ″), the mold drive control means 40 controls the mold drive means 28 so that the first bending process is executed. That is, the finished angle of the workpiece W after bending by bending at the processing for the time of pushing amount error (D ₁₎ R bending correction setting push-in amount was corrected (St 1 _'') the set pressing amount (St ₁₎ Is measured as the actually measured finished angle (θ _M ). Similarly, the calculation means 36 subtracts the push amount error (D _T ) obtained under the condition that θ = θ _T in the equation (q) from the target push amount (St _T ) and corrects the R bending correction target push. The amount (St _T ″) is set to be calculated (St _T ″ = St _T −D _T ), and the die is set according to the R bending correction target indentation amount (St _T ″) calculated by the calculation means 36. The drive control means 40 drives and controls the mold drive means 28 so that the second and subsequent bending processes are executed.

Thus, driving the upper mold 26 so as to be the set pressing amount R bending correction setting pushing amount by correcting the pressing amount error (D ₁₎ generated when the bending in _{(St 1) (St 1 '} ') By doing so, the workpiece W is actually bent at the set push-in amount (St ₁ ), so that the bending accuracy in the first bending is improved. As a result, the accuracy of the corrected bend factor (A ′) calculated based on the set push amount (St ₁ ) and the actually measured finishing angle (θ _M ) is improved, and the correction is performed based on the corrected bend factor (A ′). The processing accuracy of the second and subsequent bending processes can be increased. Further, the upper mold 26 so that the workpiece W target pushing amount (St _T) corrects the pushing amount error (D _T) which occurs during the bending in the R bending correction target pushing amount and (St T _'') By driving, the workpiece W is actually bent at the target pushing amount (St _T ), so that the workpiece W can be bent at the target finishing angle (θ _T ) with high accuracy.

(Change example)
In the embodiment, an example in which the press brake is configured to include an input unit, a setting unit, a calculation unit, and the like has been described. However, the present invention is not limited thereto, and the set finishing angle (θ ₁ ) Is set to be larger than the specific finish angle (θ _F ), and the workpiece is folded by pushing the upper die into the V groove with the set push amount (St ₁ ) corresponding to the set finish angle (θ ₁ ). The actual finished angle (θ _M ) of the workpiece bent and bent at the set indentation amount (St ₁ ) is measured, and the slope (f1) of the straight line passing through the measurement point and the inflection point in the St-θ graph, If a bending method is employed in which the target indentation amount (St _T ) is calculated so that the inflection point and the slope (f2) of the straight line passing through the processing point satisfy a predetermined relationship, the bending process is performed. Target finish angle by bending workpiece once It is possible to obtain the target pressing amount corresponding, to reduce the bending number of work required before product manufacturing can be performed it is possible to improve the productivity.

In the embodiment, the slope (f1) of the straight line passing through the measurement point and the inflection point and the slope (f2) of the straight line passing through the inflection point and the machining point are calculated so as to satisfy the relationship of the formula (f). However, it is not limited to this. That is, depending on the required bending accuracy of the workpiece, the range is set to (f1 / f2) × (V / t) <4.5, or 6.5 <(f1 / f2) × (V / t) can also be set, and in the St-θ graph, the slope (f1) of the straight line passing through the measurement point and the inflection point and the slope (f2) of the straight line passing through the inflection point and the machining point are used. By doing so, it is possible to obtain a target push-in amount corresponding to the target finish angle by one work bending. Similarly, the set finishing angle (θ ₁ ) can be set outside the range of 0.1 ° ≦ θ ₁ −θ _F ≦ 7 ° according to the required bending accuracy of the workpiece.

In the embodiment, the workpiece finishing angle (θ) and bend are changed for each workpiece machining condition (V groove angle (φ), V groove width dimension (V), workpiece material, workpiece thickness (t)). The bend factor data table indicating the relationship with the factor (A) is stored in the storage means. However, as shown in FIG. An approximate expression of a curve for each processing condition may be derived, and the corresponding bend factor (A) value may be calculated from the set finishing angle (θ ₁ ) based on the approximate expression.

18 Lower mold 20 V groove 26 Upper mold 32 Input means 34 Setting means 36 Calculation means 38 Storage means 40 Mold drive control means θ ₁ Set finish angle θ _F Specific finish angle θ _M Actual finish angle θ _T Target finish angle St ₁ set push amount St _F specific push amount St _T target push amount λ ₁ θ = θ ₁ , device deflection amount obtained under the conditions of St = St ₁ λ _T θ = θ _T , obtained under the conditions of St = St _T Device deflection amount St ₁ ′ set pushing amount (St ₁ ) + device deflection amount (λ ₁ )
St _T 'Set push amount (St _T ) + device deflection (λ _T )
Indentation amount error under the condition of D ₁ θ = θ ₁ Indentation amount error under the condition of D _T θ = θ _T St ₁ ″ Set indentation amount (St ₁ ) −Indentation amount error (D ₁ )
St _T ″ Set push amount (St _T ) −Push amount error (D _T )
f1 Inclination of straight line passing through measurement point and inflection point f1 Inclination of straight line passing through inflection point and machining point W Workpiece

Claims (14)

When the upper mold is relatively pushed into the V groove of the lower mold disposed opposite to the upper mold, the workpiece is brought into contact with the inclined surface of the V groove of the lower mold, and the finished angle of the workpiece Is a bending method using a press brake that performs a bending process so as to be a predetermined target finish angle (θ _T ),
Conditions that the set finishing angle (θ ₁ ) of the workpiece obtained by bending in the air bend state is larger than the specific finishing angle (θ _F ) of the workpiece unloaded when the workpiece contacts the inclined surface of the V groove The upper die is pushed into the V groove with the set push amount (St ₁ ) corresponding to the set finishing angle (θ ₁ ), the work is bent, and the workpiece is bent with the set push amount (St ₁ ). Measure the measured finished angle (θ _M ) of the workpiece,
In the St-θ graph showing the relationship between the indentation amount (St) of the upper mold and the finish angle (θ) of the workpiece, a point determined by the actually measured finish angle (θ _M ) and the set indentation amount (St ₁ ) is measured. A point determined by the specific indentation amount (St _F ) that is the indentation amount of the upper die corresponding to the specific finishing angle (θ _F ) and the specific finishing angle (θ _F ) is defined as an inflection point, and the target finishing Using the target push amount (St _T ), which is the push amount of the upper die corresponding to the angle (θ _T ), as the machining point, the inclination (f1) of the straight line passing through the measurement point and the inflection point, the inflection point, Bending using a press brake, wherein the target pushing amount (St _T ) is calculated and bending is performed so that the slope (f2) of the straight line passing through the processing point satisfies a predetermined relationship. Method. The target pushing amount (St _T ) is the slope (f1) of the straight line passing through the measurement point and the inflection point when the width (V) of the V groove and the plate thickness (t) of the workpiece are set as the lower mold. ) And the inclination (f2) of the straight line passing through the inflection point and the machining point are calculated so as to satisfy the relationship of the following formula (f).

A bend factor (A ₁ ) determined based on a workpiece machining condition and a workpiece finishing angle (θ) is obtained based on a set finishing angle (θ ₁ ), and A = A ₁ in the following equation (e): theta = theta calculate the set pressing amount in the _first condition (St _1), after the workpiece is bent at the set pressing amount (St _1), set pressing amount (St ₁₎ and actual finishing angle (theta _M ) To calculate the corrected bend factor (A ′) in the following formula (e) under the condition of θ = θ _M ,
Based on the specific indentation amount (St _F ) calculated from the corrected bend factor (A ′) and the specific finishing angle (θ _F ) under the conditions of A = A ′ and θ = θ _F in the following equation (e): The bending method using a press brake according to claim 1 or 2, wherein an inclination (f1) of a straight line passing through the measurement point and the inflection point is calculated.

The bending method using a press brake according to claim 3, wherein the bend factor (A ₁ ) is calculated based on the following equation (i) under the condition of θ = θ ₁ .

In the following equation (m), the device set deflection amount (λ ₁ ) obtained under the conditions of θ = θ ₁ and St = St ₁ is added to the set push amount (St ₁ ), and the corrected set push amount (St ₁ ′). Measure the bending angle of the workpiece after bending with the measured finished angle (θ _M ),
Formula (m) in the _{θ = θ T, St = St} T and the apparatus deflection amount obtained under the following conditions (lambda _T) corrected target pressing amount obtained by adding to the target pressing amount (St _T) a (St T _') 5. A bending method using a press brake according to claim 3 or 4, wherein the workpiece is bent at a step.

When bending a workpiece using an upper die whose tip is formed in an arc shape,
In the following equation (q), the indentation amount error (D ₁ ) obtained under the condition that θ = θ ₁ is subtracted from the set indentation amount (St ₁ ), and the bending amount is set by the R bending correction setting indentation amount (St ₁ ″). The bending angle of the workpiece after bending is measured as the actually measured finish angle (θ _M ),
In the following equation (q), the workpiece is calculated with an R bending correction target push amount (St _T ″) obtained by subtracting the push amount error (D _T ) obtained under the condition of θ = θ _T from the target push amount (St _T ). The bending method using the press brake according to any one of claims 3 to 5, wherein the bending is performed.

The bending finish using the press brake according to claim 1, wherein the set finishing angle (θ ₁ ) is set in a range of 0.1 ° ≦ θ ₁ −θ _F ≦ 7 °. Method. An upper mold, a lower mold having a V-groove disposed opposite to the upper mold, and a mold for driving the upper mold or the lower mold to push the upper mold into the V-groove Drive means, and when the upper mold is pushed into the V-groove by driving the mold drive means, the workpiece is brought into contact with the inclined surface of the V-groove so that the work finish angle is a predetermined target finish angle. A bending system using a press brake that performs bending so as to be (θ _T ),
An input means for inputting a machining condition of the workpiece and a target finish angle (θ _T ) of the workpiece and an actual measured finish angle (θ _M ) of the measured workpiece;
Based on the workpiece machining conditions and the target finish angle (θ _T ) input to the input means, it is larger than the specific finish angle (θ _F ) of the workpiece unloaded when the workpiece contacts the inclined surface of the V groove. A setting means for setting the set finishing angle (θ ₁ ) of the workpiece under the condition of the value;
The set push amount (St ₁ ) that is the push amount of the upper die corresponding to the set finishing angle (θ ₁ ) set by the setting means is calculated, and the set push amount (St ₁ ) and the input means Calculation means for calculating a target push amount (St _T ) that is a push amount of the upper mold corresponding to the target finish angle (θ _T ) based on the input actual finish angle (θ _M );
Drive control means for drivingly controlling the mold drive means so that the upper mold is pushed into the V-groove according to the set push amount (St ₁ ) or the target push amount (St _T ) calculated by the calculation means. ,
In the St-θ graph showing the relationship between the pressing amount (St) of the upper die and the finishing angle (θ) of the workpiece, the calculating means is based on the measured finishing angle (θ _M ) and the set pressing amount (St ₁ ). Using the determined point as a measurement point, the point determined by the specific indentation amount (St _F ) that becomes the indentation amount of the upper mold corresponding to the specific finishing angle (θ _F ) and the specific finishing angle (θ _F ) When the target push amount (St _T ), which is the push amount of the upper die corresponding to the target finish angle (θ _T ), is set as the machining point, the slope of the straight line passing through the measurement point and the inflection point ( f1) and the inclination (f2) of the straight line passing through the inflection point and the machining point are set so as to calculate the target pushing amount (St _T ) so as to satisfy a predetermined relationship,
The drive control means drives and controls the mold drive means according to the set push amount (St ₁ ) calculated by the calculation means, and the first folding process is executed. After the first bending process, In accordance with the target pushing amount (St _T ) calculated by the calculating means based on the actually measured finishing angle (θ _M ) and the set pushing amount (St ₁ ) of the workpiece input to the input means, the drive control means moves the mold driving means. A folding system using a press brake, wherein the second and subsequent folding processes are executed by driving control. The calculation means has a slope of a straight line passing through the measurement point and the inflection point in the St-θ graph when the width (V) of the V-shaped groove and the plate thickness (t) of the workpiece are set. f1) and the inclination (f2) of the straight line passing through the inflection point and the machining point are set so as to calculate the target pushing amount (St _T ) so as to satisfy the relationship of the following formula (f). Item 9. A bending system using a press brake according to item 8.

A storage means for storing a bend factor data table representing a correspondence relationship between a work finishing angle (θ) and a bend factor (A) determined based on a machining condition and a finishing angle (θ) of the work;
The calculating means includes
The bend factor (A ₁ ) corresponding to the set finishing angle (θ ₁ ) set by the setting means is determined from the bend factor data table stored in the storage means based on the workpiece machining conditions input to the input means. Acquired and set to calculate the set push amount (St ₁ ) under the conditions of A = A ₁ and θ = θ ₁ in the following equation (e),
The corrected bend factor (A ′) is calculated backward from the measured finish angle (θ _M ) and the set push amount (St ₁ ) of the workpiece input to the input means under the condition that θ = θ _M in the following equation (e). Based on the specific indentation amount (St _F ) calculated from the corrected bend factor (A ′) and the specific finishing angle (θ _F ) under the conditions of A = A ′ and θ = θ _F in the following equation (e): 10. A bending system using a press brake according to claim 8 or 9, which is set so as to calculate an inclination (f1) of a straight line passing through the measurement point and the inflection point.

The calculating means includes
The bend factor (A ₁ ) corresponding to the set finishing angle (θ ₁ ) set by the setting means is calculated under the condition that θ = θ ₁ in the following formula (i), and the following formula (e) Is set to calculate the set push amount (St ₁ ) under the conditions of A = A ₁ and θ = θ ₁ ,
The corrected bend factor (A ′) is calculated backward from the measured finish angle (θ _M ) and the set push amount (St ₁ ) of the workpiece input to the input means under the condition that θ = θ _M in the following equation (e). Based on the specific indentation amount (St _F ) calculated from the corrected bend factor (A ′) and the specific finishing angle (θ _F ) under the conditions of A = A ′ and θ = θ _F in the following equation (e): 10. A bending system using a press brake according to claim 8 or 9, which is set so as to calculate an inclination (f1) of a straight line passing through the measurement point and the inflection point.

The calculating means includes
In the following equation (m), the device set deflection amount (λ ₁ ) obtained under the conditions of θ = θ ₁ and St = St ₁ is added to the set push amount (St ₁ ), and the corrected set push amount (St ₁ ′). And a correction in which the device deflection amount (λ _T ) obtained under the condition that θ = θ _T and St = St _{T in the} equation (m) is added to the target pushing amount (St _T ) It is set to calculate the target push amount (St _T '),
According to the correction setting push amount (St ₁ ′) calculated by the calculation means, the drive control means drives and controls the mold drive means, and the first bending process is executed. The press brake according to claim 10 or 11, wherein the second and subsequent bending processes are executed by the drive control means drivingly controlling the mold drive means in accordance with the corrected target push amount (St _T '). By bending system.

The tip of the upper mold is formed in an arc shape,
The calculating means includes
The setting push amount equation given by theta = theta ₁ and the conditions in (q) pushing amount error (D ₁₎ of the following R bending correction setting pushing amount is subtracted from (St ₁₎ calculated (St 1 _'') R bending correction target push amount (St) obtained by subtracting the push amount error (D _T ) obtained under the condition that θ = θ _{T in the} equation (q) from the target push amount (St _T ) _Is set to calculate _T '')
According to the R bending correction setting push amount (St ₁ ″) calculated by the calculating unit, the drive control unit drives and controls the mold driving unit, and the first bending process is executed. 11. The second and subsequent bending processes are performed by the drive control means drivingly controlling the mold drive means in accordance with the calculated R bending correction target push-in amount (St _T ″). The bending processing system by the press brake as described in any one of -12.

14. The bending by press brake according to claim 8, wherein the setting means sets the set finishing angle (θ ₁ ) in a range of 0.1 ° ≦ θ ₁ −θ _F ≦ 7 °. Processing system.

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