DE112011100452T5 - Method and system for bending by means of bending press - Google Patents

Abstract

Bending method by means of a bending press, characterized in that by dipping an upper tool in the V-opening of the lower tool under this upper tool and touching the workpiece with the inclined surfaces of the V-opening of this lower tool, the workpiece is bent so that its production angle to set Target production angle (θT) corresponds; at this time, the target production angle (θ1) of the work obtained in canting in the free-arc state is set larger than the set production angle (θF) of the work after discharge on contact of the work with the inclined surfaces of the V-opening; the workpiece is bent by immersing the upper tool in the V-hole with a target immersion depth (St1) corresponding to this target production angle (θ1), and the actual production angle (θM) of the workpiece folded at this target insertion depth (St1) is measured; from the St / θ graph, which shows the relationship between the immersion depth (St) of the upper tool and the production angle (θ) of the workpiece, the target immersion depth (StT) for the folding is calculated so that the slope (f1) of Just by measuring point and ...

Description

Technical part

The present invention relates to a method and system for bending by means of a bending press, in which a workpiece is folded by dipping an upper tool in the V-shaped opening of a lower tool at the targeted angle.

Technical background

Typical prior art bending presses, as described in Patent Document 1, are constituted by an upper tool and an underlying lower tool having a V-shaped opening, which are arranged so that the upper and lower tools approach each other; In this case, the workpiece is folded by dipping the upper tool in the V-shaped opening of the lower tool at a predetermined angle. In bending presses with up and down movement of a plunger, on which such an upper tool is mounted about a tabular o. Ä. Workpiece is supported on the lower tool and applied by downward movement of the upper tool together with the plunger, a pressing force on the workpiece, while the upper tool immersed in the V-hole; As a result, the workpiece is bent at a predetermined angle. The angle at which the workpiece is folded is thus defined by how far the upper tool moves from abutting the workpiece to the lower end position (insertion depth of the upper tool / stroke).

It is well known that the bending angle of such a workpiece after relieving the upper tool, with which this workpiece is loaded, and the removal from the tool by the springback is greater than the bending angle of the workpiece during the load by the upper tool. To abzukanten a workpiece at the targeted angle, therefore, before bending the workpiece on the basis of material and material thickness of the workpiece to be machined, the shape of upper and lower tool, the angle and width of the V-opening, the rigidity of the machine, etc. the Immersion depth of the upper tool calculated. In the context of this description, the bending angle of the workpiece in the clamped state between the upper and lower tool is referred to as the "clamping angle" and the bending angle of the workpiece in the spring-loaded state after relief as "production angle".

Documents on the state of the art

Patent documents

• Patent Document 1: Laid-Open Publication JP 2002-79319 A

Summary of the invention

Object of the invention

For the depth of immersion of the upper tool, the influence of calculation factors such as material and material thickness of the workpiece, shape of upper and lower tool, angle and width of the V-opening, rigidity of the machine, etc. is first recorded in a database; The immersion depth is then calculated on the basis of the calculation factors in this database. However, such databases do not fully match the values achieved with workpieces, bending presses, etc., during machining in practice, but only within certain tolerances; therefore, it has heretofore been difficult to achieve the target values for the final angle of production of the final workpiece at one time.

When folding workpieces, therefore, bending tests are undertaken in order to check the accuracy of the machining with the calculated insertion depth of the upper tool and to regulate this. Thus, a trial workpiece is first folded, the production angle of this bent workpiece measured and then adapted to this production angle according to the immersion depth of the upper tool. Then, with the adjusted immersion depth of the upper tool, the next workpiece is folded; This is followed by several passes, in each of which the production angle of the workpiece is measured and the immersion depth of the upper tool is further adjusted until the exact depth of immersion of the upper tool is reached by trial and error, with which the workpiece can be tilted in the targeted production angle , To set a value for the immersion depth of the upper tool receive, with which the target production angle can be achieved, so several bending tests must be undertaken; the loss of time and material until the actual folding of workpieces can be started, and the resulting loss of productivity represent a major problem.

In particular, when bent so that the workpiece comes into contact with the inclined surfaces thereof when the upper tool is dipped in the V-hole, the bending properties of the workpiece considerably change due to its contact with the inclined surfaces of the V-hole; the determination of the exact depth of immersion of the upper tool by computational means is therefore difficult; because of the need to perform several bending tests, there was a great need for improvement.

As a method for edging workpieces with the targeted manufacturing angle and thereby facilitating such bending tests on the workpiece, while methods for measuring the bending angle of the workpiece (the clamping angle) during the bending process, such as in the mentioned patent document 1, are known. Specifically, a sensor is attached to the upper tool, which comes into contact with the workpiece and measures the clamping angle on the workpiece during the Abkantens; then the manufacturing angle of the temporarily relieved workpiece is measured, determined from the difference between clamping angle and manufacturing angle when relieving the Rückfedermaß and based on which determines the additional required immersion depth with which the workpiece is then folded. However, if the workpiece must be folded so that it touches the inclined surfaces of the V-opening during bending, this significantly changes the bending properties of the workpiece, so that even with the use of processing methods with in-process measurement by such sensors, the Abkantbearbeitung the workpiece still must be performed several times and a high processing efficiency can not be achieved. In this machining process, it has also been pointed out that the mounting of sensors leads to larger tools and more complicated equipment and is associated with significant limitations of the machinable workpiece shape, that the application area of the plant is narrowed and simultaneously the measuring surface of the sensor depending on the material of the workpiece is contaminated by contact with the sensor and an accurate measurement is therefore not guaranteed. In order to enable measurements with high accuracy, more expensive sensors would also have to be used, which would increase the production costs of the plant. In practice, said bending method with in-process measurement by sensors is therefore hardly suitable for general use.

The aim of the present invention, which proposes a preferred solution for the abovementioned object of the prior art, is therefore to provide a method and system for bending by means of a bending press, with which the insertion depth of the upper tool can be adjusted according to the final target. Production angle of the workpiece can be determined by one-time bending.

Solution of the task

The method for bending by bending press according to claim 1 of the present application, with which the mentioned object is achieved and the set target is to be achieved, is characterized in that by dipping an upper tool ( 26 ) into the V-opening ( 20 ) of the under this upper tool ( 26 ) lower tool ( 18 ) and contact of the workpiece (W) with the inclined surfaces of the V-opening ( 20 ) of this sub tool ( 18 ) the workpiece (W) is bent so that its production angle corresponds to the specified target production angle (θ _T ); In this case, the target production angle (θ ₁ ) of the workpiece (W), which is achieved in bending in freigebogenem state, set greater than the specified manufacturing angle (θ _F ) of the workpiece (W) after discharge upon contact of the workpiece (W) with the sloping surfaces of the V-opening ( 20 ); the workpiece (W) is removed by dipping the upper tool ( 26 ) into the V-opening ( 20 ) with a desired immersion depth (St ₁ ) according to this target production angle (θ ₁ ) bent and the actual production angle (θ _M ) of the workpiece with this desired immersion depth (St ₁ ) beveled workpiece (W) measured; using the St / θ graph, which shows the relationship between the immersion depth (St) of the upper tool ( 26 ) and the production angle (θ) of the workpiece (W), the target immersion depth (St _T ) for the folding is calculated so that the slope (f1) of the straight line through the measuring point and inflection point on the one hand and the slope (f2) of the straight line on the other hand, they are in fixed relation to each other through the turning point and the machining point; where the measuring point is defined by the actual production angle (θ _M ) and the desired immersion depth (St ₁ ), the inflection point by the specified production angle (θ _F ) and the specified immersion depth (St _F ), with an immersion depth of the upper tool ( 26 ) is achieved according to the set production angle (θ _F ); the processing point, on the other hand, is defined by the target production angle (θ _T ) and the target immersion depth (St _T ), with which an immersion depth of the upper tool ( 26 ) is achieved according to the target production angle (θ _T ).

The method for bending by bending press according to claim 2 is characterized in that the target immersion depth (St _T ) is calculated so that the slope (f1) of the straight line by measuring point and inflection point on the one hand and the slope (f2) of the straight line by inflection point and On the other hand, in the relationship described by formula (f) below, where (V) is the width of the V opening (FIG. 20 ) of the lower tool ( 18 ) and (t) is the material thickness of the workpiece (W).

[Point 5]

[Formula (f)]

• 4.5 ≤ (f1 / f2) x (V / t) ≤ 6.5

The method for bending by means of a bending press according to claim 3 is characterized in that a by the processing conditions of the workpiece (W) and the production angle (θ) of the workpiece (W) defined Abkantfaktor (A ₁ ) based on the target manufacturing angle (θ ₁ ) determined and calculating the target immersion depth (St ₁ ) according to formula (e) below with A = A ₁ and θ = θ ₁ ; after the workpiece has been folded (W) with this desired immersion depth (St ₁ ), the correction factor (A ') with θ is calculated via the set immersion depth (St ₁ ) and the actual production angle (θ _M ) according to formula (e) below = θ _M calculated; then the specified immersion depth (St _F ) is calculated using the correction factor (A ') and the specified production angle (θ _F ) according to formula (e) below with A = A' and θ = θ _F ; Based on this immersion depth, the slope (f1) of the straight line is again calculated by measuring point and inflection point.

[Number 4]

[Formula (e)]

• R:

  Inner radius of the bending part on the workpiece

  A:

  bend factor

  θ:

  Production angle of the workpiece

  St:

  Immersion depth

  R _d :

  Radius of the support surface of the lower tool

  V:

  Width of the V-opening

  φ:

  Angle of the V-opening

  α:

  (180 - θ) / 2,

  δ:

  Compensation dimension for springback of the workpiece

  σ _0.2 :

  Strength of the workpiece

  e:

  E-modulus of the workpiece

The method for bending by means of bending press according to claim 4 is characterized in that the Abkantfaktor (A ₁ ) according to formula (i) below with θ = θ _{1 is} calculated.

[Number 8]

[Formula (i)]

• θ _x:

  maximum production angle with which the workpiece can be folded

  θ _y :

  Approach angle

  d, e:

  material-specific workpiece coefficients

The method for bending by means of bending press according to claim 5 is characterized in that the Abkantwinkel of the workpiece (W) after folding with the corrected target immersion depth (St ₁ '), resulting from the desired immersion depth (St ₁ ) plus after Formula (m) below with θ = θ ₁ and St = St ₁ composed spring deflection of the plant (λ ₁ ) composed, as actual production angle (θ _M ) is measured; then the workpiece (W) with the corrected target immersion depth (St _T ') resulting from the target immersion depth (St _T ) plus the spring deflection calculated according to formula (m) below with θ = θ _T and St = St _T the plant (λ _T ) composed, folded.

[Number 12]

[Formula (m)]

• λ = W / k
• i) for θ ≥ θ _A : W = W _a
• ii) for θ _F ≤ θ ≤ θ _A :
  
• iii) for θ ≤ θ _F : W = W _f + k _W × (St - St _F ), in which
  
  k ₁ = -0.055 × V / t + 1.753 W _f = k _f × W _a k _w = {k _a × ln (t) + k _b } × W _a

  θ _A :

  Manufacturing angle for reference machining force; here 135 °

  St _A :

  Immersion depth corresponding to θ _A

  W _a :

  Reference machining force

  k:

  Longitudinal stiffness coefficient of the plant

  σ _B :

  Tensile strength of the workpiece

  ω:

  Folding

  k ₁ :

  Coefficient calculated from the ratio between the width of the V-hole of the lower tool and the material thickness of the workpiece

  k _f, k _a, k _b:

  material-specific workpiece coefficients

The method for bending by means of bending press according to claim 6 is characterized in that the edge of this upper tool is arcuate in the bending of workpieces by means of an upper tool, the Abkantwinkel the workpiece after folding with the radius bending corrected target immersion depth (St ₁ ''), the is composed of the desired immersion depth (St ₁ ) minus the immersion depth deviation (D ₁ ) calculated according to formula (q) below with θ = θ ₁ , measured as the actual production angle (θ _M ); then the workpiece is bent with the radius bending corrected target immersion depth (St _T ''), which is calculated from the target immersion depth (St _T ) minus the immersion depth deviation (D _T ) calculated according to formula (q) below with θ = θ _T ,

[Paragraph 16]

[Formula (q)]

• D = (R _P -R) × 1-cosα / cosα

The method for bending by bending press according to claim 7 is characterized in that the target manufacturing angle (θ ₁ ) is set in the range of 0.1 ° ≤ θ ₁ -θ _F ≤ 7 °.

The press brake bending system according to claim 8 of the present application, which is intended to solve the mentioned object and to achieve the set target, is characterized in that said system for bending by means of a bending press via an upper tool ( 26 ), one under this upper tool ( 26 ) lying lower tool ( 18 ) with V-opening ( 20 ) and via a tool drive element ( 28 ), with which the upper tool ( 26 ) or lower tool ( 18 ) is driven so that the upper tool ( 26 ) into the V-opening ( 20 ), the workpiece (W) during immersion of the upper tool ( 26 ) into the V-opening ( 20 ) by driving with the tool drive element ( 28 ) the inclined surfaces of the V-opening ( 20 ) and the angle of manufacture of the workpiece (W) during bending corresponds to the set target production angle (θ _T ); this system has an input element ( 32 ) with which both the machining conditions and the target machining angle (θ _T ) of the workpiece (W) and the measured actual machining angle (θ _M ) of the workpiece (W) are input via an adjusting member (FIG. 34 ), with which by the input element ( 32 ) inputted machining conditions and the target production angle (θ _T ) on the workpiece (W) of the target manufacturing angle (θ ₁ ) of the workpiece (W) is set to be greater than the predetermined manufacturing angle (θ _F ) of the workpiece (W) after discharge upon contact of the workpiece (W) with the inclined surfaces of the V-opening ( 20 ), via a computing element ( 36 ), with which the desired immersion depth (St ₁ ) is calculated so that an immersion depth of the upper tool ( 26 ) according to the via the adjusting element ( 34 ) set target production angle (θ ₁ ), and with the basis of this target immersion depth (St ₁ ) and via the input element ( 32 Input) Actual production angle (θ _M), the target depth of immersion (St _T) is calculated so that an immersion depth of the top tool ( 26 ) according to the target manufacturing angle (θ _T ); as well as via a drive control element ( 40 ), with which the drive is controlled by the tool drive element so that the upper tool ( 26 ) according to the via the computing element ( 36 ) calculated target immersion depth (St ₁ ) or target immersion depth (St _T ) in the V-opening ( 20 immersed); the computing element ( 36 ) is set to calculate a target immersion depth (St _T ) at which the slope (f1) of the straight line passes through measurement point and Turning point on the one hand and the slope (f2) of the straight line by turning point and machining point on the other hand are in a fixed relationship to each other; it is in the St / θ graph, the relationship between the immersion depth (St) of the upper tool ( 26 ) and the production angle (θ) of the workpiece (W), the measurement point defined by the actual production angle (θ _M ) and the target immersion depth (St ₁ ), the inflection point by the set production angle (θ _F ) and the set immersion depth (St _F ), with an immersion depth of the upper tool ( 26 ) is achieved according to the set production angle (θ _F ); the processing point, on the other hand, is defined by the target production angle (θ _T ) and the target immersion depth (St _T ), with which an immersion depth of the upper tool ( 26 ) is achieved according to the target production angle (θ _T ); First of all, by drive control of the tool drive element ( 28 ) via the drive control element ( 40 ) according to the by the computing element ( 36 ) calculated target immersion depth (St ₁ ) folded; After this first bending operation, starting from the second bending operation by drive control of the tool drive element (FIG. 28 ) via the drive control element ( 40 ) according to the target immersion depth (St _T ), which is determined by the computing element ( 36 ) on the basis of the input element ( 32 ) input actual working angle (θ _M ) of the workpiece (W) and the desired immersion depth (St ₁ ) was calculated, folded.

The system for bending by bending press according to claim 9 of the present application is characterized in that the computing element ( 36 ) is set so that the target immersion depth (St _T ) is calculated so that in the St / θ graph, the slope (f1) of the straight line by measuring point and inflection point on the one hand and the slope (f2) of the straight line by inflection point and processing point on the other hand, in the relationship defined by the formula (f) below, where (V) is the width of the V opening ( 20 ) of the lower tool ( 18 ) and (t) is the material thickness of the workpiece (W).

[Point 5]

[Formula (f)]

• 4.5 ≤ (f1 / f2) x (V / t) ≤ 6.5

The system for bending by bending press according to claim 10 of the present application is characterized in that this system via a memory element ( 38 ), in which a Abkantfaktoren data table is deposited, showing the relationship between the production angle (θ) of the workpiece (W) and on the basis of machining conditions and manufacturing angle (θ) of the workpiece (W) calculated Abkantfaktor (A); while the computing element ( 36 ) is set so that the Abkantfaktor (A ₁ ) according to the over the adjustment ( 34 ) set target production angle (θ ₁ ) by means of the input element ( 32 ) input machining conditions of the workpiece (W) from the in the memory element ( 38 ) and the set immersion depth (St ₁ ) is calculated according to the formula (e) below with A = A ₁ and θ = θ ₁ and based on the input element ( 32 ) input actual working angle (θ _M ) of the workpiece (W) and the desired immersion depth (St ₁ ) of the correction factor (A ') according to the formula (e) below with θ = θ _M determined based on the correction factor (A') and the set production angle (θ _F ) according to the formula (e) below with A = A 'and θ = θ _F the calculated immersion depth (St _F ) is calculated and based on this the slope (f1) of the straight line is calculated by measuring point and inflection point.

[Number 4]

[Formula (e)]

• R:

  Inner radius of the bending part on the workpiece

  A:

  bend factor

  θ:

  Production angle of the workpiece

  St:

  Immersion depth

  R _d :

  Radius of the support surface of the lower tool

  V:

  Width of the V-opening

  φ:

  Angle of the V-opening

  α:

  (180 - θ) / 2

  δ:

  Compensation dimension for springback of the workpiece

  σ _0.2 :

  Strength of the workpiece

  e:

  E-modulus of the workpiece

The system for bending by bending press according to claim 11 of the present application is characterized in that the computing element ( 36 ) is set so that the Abkantfaktor (A ₁ ) according to the via the setting ( 34 ) setpoint production angle (θ ₁ ) according to the formula (i) below with θ = θ ₁ and calculated the desired immersion depth (St ₁ ) according to the formula (e) below with A = A ₁ and θ = θ ₁ and by means of the input element ( 32 ) input actual working angle (θ _M ) of the workpiece (W) and the desired immersion depth (St ₁ ) according to the formula (e) below with θ = θ _M, the correction factor (A ') determined based on the correction factor (A') and the set production angle (θ _F ) according to the formula (e) below with A = A 'and θ = θ _F the calculated immersion depth (St _F ) is calculated and based on this the slope (f1) of the straight line is calculated by measuring point and inflection point.

[Number 4]

[Formula (e)]

• R:

  Inner radius of the bending part on the workpiece

  A:

  bend factor

  θ:

  Production angle of the workpiece

  St:

  Immersion depth

  R _d :

  Radius of the support surface of the lower tool

  V:

  Width of the V-opening

  φ:

  Angle of the V-opening

  α:

  (180 - θ) / 2

  δ:

  Compensation dimension for springback of the workpiece

  σ _0.2 :

  Strength of the workpiece

  e:

  E-modulus of the workpiece

[Number 8]

[Formula (i)]

• θ _x:

  maximum production angle with which the workpiece can be folded

  θ _y :

  Approach angle

  d, e:

  material-specific workpiece coefficients

The system for bending by bending press according to claim 12 of the present application is characterized in that the computing element ( 36 ) is adjusted so that from the desired immersion depth (St ₁ ) plus the determined according to the formula (m) below with θ = θ ₁ and St = St ₁ springing the system (λ ₁ ), the corrected target immersion depth (St ₁ ') and calculated from the target immersion depth (St _T ) plus the according to this formula (m) with θ = θ _T and St = St _T determined springing of the system (λ _T ) the corrected target immersion depth (St _T ') is, and is constructed so that initially only by drive control of the tool drive element ( 28 ) via the drive control element ( 40 ) according to the by the computing element ( 36 ) calculated corrected immersion depth (St ₁ ') bent and from the second bending operation by drive control of the tool drive element ( 28 ) via the drive control element ( 40 ) according to the by this computing element ( 36 ) calculated corrected target immersion depth (St _T ') is folded.

[Number 12]

[Formula (m)]

• λ = W / k
• i) for θ ≥ θ _A : W = W _a
• ii) for θ _F ≤ θ ≤ θ _A :
  
• iii) for θ ≤ θ _F : W = Wf + k _W × (St - St _F ), in which
  
  k ₁ = -0.055 × V / t + 1.753 W _f = k _f × W _a k _w = {k _a × ln (t) + k _b } × W _a

  θ _A :

  Manufacturing angle for reference machining force; here 135 °

  St _A :

  Immersion depth corresponding to θ _A

  W _a :

  Reference machining force

  k:

  Longitudinal stiffness coefficient of the plant

  σ _B :

  Tensile strength of the workpiece

  ω:

  Folding

  k ₁ :

  Coefficient calculated from the ratio between the width of the V-hole of the lower tool and the material thickness of the workpiece

  k _f, k _a, k _b:

  material-specific workpiece coefficients

The system for bending by bending press according to claim 13 of the present application is characterized in that the tip of the upper tool is circular arc-shaped, and the computing element is set so that the radius bending corrected target immersion depth (St ₁ ''), resulting from the target Immersion depth (St ₁ ) minus the immersion depth deviation (D ₁ ) determined according to formula (q) below with θ = θ ₁ , and the radius bend corrected target immersion depth (St _T '') resulting from the target immersion depth (St _T ) minus the immersion depth deviation (D _T ) determined according to this formula (q) with .theta. =. theta. _T , and constructed such that first of all by drive control of the tool drive element via the drive control element in accordance with the radius bending-corrected desired insertion depth calculated by the computation element (St ₁ '') bent and from the second bending operation by drive control of the tool drive bselements via the drive control element according to the by this computing element ( 36 ) calculated radius bending corrected target immersion depth (St _T '') is bent.

[Paragraph 16]

[Formula (q)]

• D = (R _P -R) × 1-cosα / cosα

The bending press-bending system according to claim 14 of the present application is characterized in that the target manufacturing angle (θ ₁ ) is set via the adjusting element (13). 34 ) is set in the range of 0.1 ° ≦ θ ₁ -θ _F ≦ 7 °.

Advantages of the invention

With the method and system for bending by means of bending press according to the present invention can also be in Abkantverfahren in which the workpiece at the target production angle with the inclined surfaces of the V-opening of the lower tool must be brought into contact, by a single edge of a workpiece a target - calculate the immersion depth that corresponds to the target production angle, which reduces the number of required bending operations on the workpiece until good parts can be produced and increases productivity. Furthermore, since the bending angle on the workpiece does not have to be measured during the bending process, general-purpose universal tools can be used can be used without the need for upper and lower tool sensors, which allows easy bending of workpieces with the target production angle without restrictions on the machinable workpiece shape.

Furthermore, when the slope of the straight line by measuring point and inflection point on the one hand and the slope of the straight line by turning point and machining point on the other hand in the relationship defined by formula (f), workpieces with high accuracy in the target manufacturing angle can be tilted.

Furthermore, by calculating the Abkantfaktors according to formula (i), it is no longer necessary to previously capture the Abkantfaktoren for the individual processing conditions of the workpiece in a database, while at the same time a wider range of target production angles can be realized and the usability is extended. Next can be achieved by correcting the springing of the system when folding the workpiece a more accurate Abkantbearbeitung the workpiece. Furthermore, when bending by means of an upper tool whose tip is circular arc-shaped, a more accurate bending machining of the workpiece can be achieved by correcting the deviation (offset) between the tip of the upper tool and the lowest point of the bending part on the workpiece.

Brief explanation of the illustrations

[ ] Bending press according to an embodiment of the present invention in plan view

[ ] Representation of the Abkantbearbeitung a workpiece with a bending press according to an embodiment; (a) shows the upper tool in contact with the workpiece before folding, while (b) shows the workpiece in contact with the inclined surfaces of the V-hole of the lower tool when the upper tool is dipped in the V-hole.

[ ] Block diagram for the relationship of input element, control device and tool drive element of a bending press according to an embodiment

[ ] Graph on the relationship between width of the V-opening / material thickness and the specified production angle when folding workpieces

[ ] St / θ graph on the relationship between the insertion depth of the upper tool and the production angle of the workpiece / scheme for the relationship between the measuring point, inflection point and machining point when folding workpieces

[ ] Diagram, from which the formula for the relationship between upper / lower tool and workpiece can be derived when bending workpieces by means of a bending press

[ ] Diagram, from which the formula for the relationship between upper / lower tool and workpiece can be derived when bending workpieces by means of a bending press; where (a) shows the relationship between the workpiece and the lower tool, while (b) shows the enlarged section X of Fig. (a).

[ ] Graph on the relationship between the target production angle and the cold rolled steel sheet (SPCC) as a component of a press brake datum table stored in the memory element

[ ] Graph on the test results when folding workpieces with a V-opening width of V = 8 mm in the first example experiment

[ ] Graph on the test results in the bending of workpieces with a width of the V-opening of V = 10 mm in the first example experiment

[ ] Graph on the test results when folding workpieces with a width of the V-opening of V = 12 mm in the first example experiment

[ ] Graph on the test results when folding workpieces with a V-opening width of V = 16 mm in the first example experiment

[ ] Graph on the test results when folding workpieces with a width of the V-opening of V = 12 mm and a workpiece material thickness of t = 1.5 mm in the second example experiment

[ ] Graph on the test results when folding workpieces with a width of the V-opening of V = 12 mm and a workpiece material thickness of t = 2.0 mm in the second example experiment

[ ] Graph on the test results when folding workpieces with a width of the V-opening of V = 16 mm and a workpiece material thickness of t = 3.0 mm in the second example experiment

[ ] Graph on the test results when folding workpieces with a width of the V-opening of V = 12 mm and a workpiece material thickness of t = 1.5 mm in the third example experiment

[ ] Graph on the test results when folding workpieces with a width of the V-opening of V = 16 mm and a workpiece material thickness of t = 3.0 mm in the third example experiment

[ ] Graph on the test results when folding workpieces with a width of the V-opening of V = 12 mm and a workpiece material thickness of t = 1.0 mm in the fourth example experiment

[ ] Graph on the test results when folding workpieces with a width of the V-opening of V = 16 mm and a workpiece material thickness of t = 1.5 mm in the fourth example experiment

[ ] Graph of the test results when folding workpieces with a width of the V-opening of V = 12 mm and a workpiece material thickness of t = 1.0 mm in the fifth example experiment

[ ] Graph on the test results when folding workpieces with a width of the V-opening of V = 16 mm and a workpiece material thickness of t = 1.5 mm in the fifth example experiment

[ ] Graph on the test results when folding workpieces with a width of the V-opening V = 12 mm and a workpiece material thickness of t = 1.0 mm in the sixth example experiment

[ ] Graph on the test results when folding workpieces with a width of the V-opening V = 10 mm and a workpiece material thickness of t = 1.5 mm in the sixth example experiment

[ ] Graph on the test results when folding workpieces with a width of the V-opening V = 12 mm and a workpiece material thickness of t = 2.0 mm in the sixth example experiment

[ ] Graph of the test results when folding workpieces with a width of the V-opening of V = 6 mm and a workpiece material thickness of t = 1.0 mm in the seventh example experiment

[ ] Graph on the test results in the bending of workpieces with a width of the V-opening of V = 10 mm and a workpiece material thickness of t = 1.5 mm in the seventh example experiment

[ ] Graph on the test results in the bending of workpieces with a width of the V-opening of V = 12 mm and a workpiece material thickness of t = 2.0 mm in the seventh example experiment

[ ] Graph on the test results when folding workpieces with a width of the V-opening of V = 12 mm and a workpiece material thickness of t = 1.0 mm in the eighth example experiment

[ ] Graph on the test results when folding workpieces with a width of the V-opening of V = 16 mm and a workpiece material thickness of t = 1.5 mm in the eighth example experiment

[ ] Graph on the test results for the bending of workpieces with a width of the V-opening of V = 18 now and a workpiece material thickness of t = 2.0 mm in the eighth example experiment

[ ] Graph with the production angle (θ) on the x-axis and the ratio between the Abkantfaktor (A) at the corresponding production angle (θ) on the one hand and the Abkantfaktor (A ₁₀₀ ) at a production angle of 100 ° on the other hand on the y-axis; The dashed line shows the average of the values for A / A ₁₀₀ at the respective production angles.

[ Graph on the relationship between the width of the V-opening (V) divided by the material thickness (t) on the one hand and the Abkantfaktor at a production angle of 100 ° (A ₁₀₀ ) divided by the width of the V-opening (V) on the other hand for cold-rolled steel sheet (SPCC)

[ ] Graph on the relationship between immersion depth (St) and working force (W)

[ Graph on the relationship between the width of the V-opening (V) divided by the material thickness (t) on the one hand and the coefficient (k ₁ ) on the other

[ ] Graph with the material thickness (t) of the workpiece W on the x-axis and k _w / W _a on the y-axis when folding with an upper tool immersion depth (St) greater than or equal to the specified immersion depth (St _F ), where k _w represents the relationship between the increase in immersion depth (St) and the change in machining force (W).

[ ] Scheme for folding a workpiece with an upper tool whose tip is circular arc-shaped

[ Graph on the relationship between the radius bend-corrected penetration depth (St '') determined by formula (n) and the angle of manufacture (θ) for edging an aluminum workpiece (A5052P) with a tip radius of the upper tool of R _p = 1.0 mm, a width the V-opening of V = 6 mm and a material thickness of t = 1.0 mm; as well as the calculated values of the radius bend-corrected immersion depth (St '') determined by FEM analysis; The dashed line shows the relationship between the immersion depth (St) determined according to formula (e) and the production angle (θ).

Embodiments of the present invention

In the following, the method and system for bending by bending press according to the present invention will be described in detail with reference to some preferred embodiments with reference to the accompanying drawings.

Embodiment 1

shows a diagram of the bending press 10 according to the present embodiment 1. In this bending press 10 is on the below the side surfaces of a C-shaped pair of left and right side frames 12 . 12 located bed 14 a sub-table 16 attached, on the turn, a lower tool 18 is detachably attached; at the same time is on the side surfaces of the page frame 12 . 12 a pestle 22 vertically movably mounted. At the bottom of this pestle 22 , opposite to that on the undercounter 16 attached lower tool 18 , is a holder 24 attached, in turn, an upper tool 26 is detachably attached. The bending press is further constructed so that at the top of the pair of left and right side frames 12 . 12 the cylinder pistons exemplified as tool drive elements 28 attached hydraulic cylinder respectively with the left and right upper edge of the plunger 22 are connected, so that the plunger 22 driven vertically by the hydraulic cylinder and thus the upper tool 26 moved up and down.

For these tool drive elements 28 Not only can hydraulic cylinders be used, but also servo-driven ball screws or other elements of the prior art.

As in is shown at the top of the lower tool 18 an upwardly open V-shaped opening 20 (hereinafter referred to as "V-opening") formed across the width of the press brake 10 extends; during downward movement of the plunger 22 dives the upper tool 26 according to the V-opening 20 one. By downward movement of the plunger 22 while the workpiece W is above the V-opening 20 away on the lower tool 18 is supported, accordingly, the pressing force of the upper tool 26 on the workpiece W, whereby the workpiece W is folded at a specified angle. This is the bending press 10 in the embodiment 1 by a type in which the upper tool 26 for bending the workpiece W by downward movement in the V-opening 20 of the lower tool 18 dips; However, the workpiece W can also be folded in the same way when the bending press is constructed so that the upper tool 26 by vertical movement of the lower tool 18 via drive via tool drive elements 28 in the V-opening 20 of the lower tool 18 dips. Unless the top tool 26 in the V-opening 20 of this upper tool 26 opposite lower tool 18 dive, the bending press so only needs to be constructed so that one of the two tools 18 and 26 moved vertically.

The bending press 10 also has a control unit 30 for controlling this bending press 10 ; This one is designed to be based on the one with this controller 30 connected input element 32 (Input device) input machining conditions of the workpiece, the immersion depth of the upper tool 26 (Measure of the downward movement of the upper tool 26 calculated from abutment on the workpiece W) and the tool drive element 28 via a in the control unit 30 installed tool drive control 40 is driven so that the plunger 22 moved vertically, so that the upper tool 26 exactly up to the calculated immersion depth in the V-opening 20 dips. It will be in the input element 32 both tool data and the angle of the V-hole 20 of the lower tool 18 (eg, 80 °, 88 °, 90 °, etc.), the width (V) of the V-hole 20 of the lower tool 18 or the tip angle of the upper tool 26 (For example, 80 °, 88 °, 90 °, etc.) as well as data on the machined workpiece as the material or the material thickness (t) of the workpiece W entered. The structure is further designed so that in the input element 32 the targeted production angle of the workpiece W for the means of bending press 10 folded final product (hereinafter referred to as target production angle (θ _T )) as well as the measured after initial bending actual value for the production angle of the workpiece W (hereinafter referred to as actual production angle (θ _M )) are entered; The control unit calculates on the basis of these input values 30 the immersion depth of the upper tool 26 at the first bending (hereinafter referred to as the desired immersion depth (St ₁ )) and the immersion depth of the upper tool 26 from the second bending process (hereinafter referred to as target immersion depth (St _T )). Furthermore, in the bending press 10 according to embodiment 1 for the different types of tools 18 . 26 in each case the tool data of the upper and lower tool 18 . 26 in the memory element 38 of the control unit 30 preset, so that by selecting the tools to be used for the folding 18 . 26 via the input element 32 the corresponding tool data are obtained automatically.

The following is the procedure for calculating the desired immersion depth (St ₁ ) and target immersion depth (St _T ) with the control unit 30 described. The control unit 30 has an adjustment element 34 for setting the by using the input element 32 entered input values (machining conditions of the workpiece W and target production angle (θ _T )) calculated manufacturing angle of the workpiece W, which is bent at the first pass (hereinafter referred to as target manufacturing angle (θ ₁ )) and a computing element 36 (please refer ), the basis of the above the adjustment 34 set. Target production angle (θ ₁ ) the desired immersion depth (St ₁ ), with the upper tool 26 submerges, and further on the basis of this target immersion depth (St ₁ ) and the on the input element 32 entered actual production angle (θ _M ) the immersion depth of the upper tool 26 that corresponds to this target manufacturing angle (θ _T ) (ie, the target immersion depth (St _T )). The bending press 10 According to Embodiment 1 is thus constructed so that by a single folding of a workpiece, the target immersion depth (St _T ) of the upper tool 26 , which corresponds to the final target production angle (θ _T ) of the workpiece W, and that from the second bending operation on this workpiece W, a workpiece W bent to the target production angle (θ _T ) is produced.

Here is the adjustment 34 is so constructed that the target manufacturing angle (θ ₁ ) is set larger than the manufacturing angle of the workpiece W after relief on contact of the workpiece W with the inclined surfaces of the V-hole 20 of the lower tool 18 (hereinafter referred to as a specified production angle (θ _F )). In experiments, it was possible to prove that the specified production angle (θ _F ) is specific to the individual materials of the workpiece W by the material thickness (t) of the workpiece W and the width (V) of the V-opening 20 can be determined: the value for V / t and the specified production angle (θ _F ) for the individual materials of the workpiece W are in the shown context. Here is the adjustment 34 is set to the formula (a) below for calculating the inflection point at which the in shown curves are approximated by a quadratic function; on the basis of the input element 32 input processing conditions for the workpiece W (specifically: the width (V) of the V-opening 20 , the material thickness (t) of the workpiece W and the material of the workpiece W), the set production angle (θ _F ) is calculated, and at the same time the target production angle (θ ₁ ) is set larger than the set production angle (θ _F ). a, b and c are here material-specific coefficients for the workpiece W; Table 1 shows the coefficients of exemplary workpieces W when the angle of the V-opening 20 of the lower tool 18 88 °.

[Number 1]

[Formula (a)]

• θ _F = a × (V / t) ² + b × (V / t) + c

[Table 1] SPCC A5052P SUS304 SUS430 C2801 - 1 / 4H a -0.0133 -0.0406 -0.0114 -0.0144 -0.0329 b .3489 .9538 .4695 .4573 .9128 c 87.718 86.547 87.818 87.578 86.723

In this case, the target production angle (θ ₁ ) in the adjustment 34 the bending press 10 according to the embodiment 1 in the range of 0.1 ° ≤ θ ₁ - θ _F ≤ 7 ° set.

In the St / θ graph (see ), which determines the relationship between the immersion depth (St) of the upper tool 26 when bending the workpiece W and the manufacturing angle (θ) of the workpiece W, the target manufacturing angle (θ _T ) is calculated by the computing element as described below 36 calculated from the change of the slope f1 or f2 of the straight line around the turning point (a point defined by the fixed insertion depth (St _F ) and the specified production angle (θ _F )); because the relationship between the immersion depth (St) of the upper tool 26 and the manufacturing angle (θ) of the workpiece W due to process characteristics in bending does not correspond to a perfectly linear function, the target immersion depth (St ₁ ) can be set by setting the target production angle (θ ₁ ) in the range of 0.1 ° ≤ θ ₁ - θ _F ≤ 7 ° and as far as possible approximation of the measuring point (a point defined by the set immersion depth (St ₁ ) and the measured production angle (θ _M )) to the inflection point with high accuracy. On the other hand, because of dimensional tolerances, etc., in the material thickness (t) of the workpiece W, the bending properties of the workpiece upon its contact with the inclined surfaces of the V-hole 20 during the chipping, when the target manufacturing angle (θ ₁ ) is set in a range of θ ₁ -θ _F ≤ 0.1 °, it should preferably be in a range of 0.1 ° ≤ θ ₁ -θ _F be set. If no high-precision folding is required, the target production angle (θ ₁ ) can of course also be set so that θ ₁ - θ _{F is} outside the limits specified above.

After so the target manufacturing angle (θ ₁ ) on the adjustment 34 is set is via the computing element 36 calculated on the target manufacturing angle (θ ₁ ) the desired immersion depth (St ₁ ). In this case, the desired immersion depth (St ₁ ) on the basis of the geometric Abkantform of the workpiece W from the formula for the relationship between the manufacturing angle of the relieved workpiece W after free bending and the immersion depth of the upper tool 26 derived.

Here is briefly on the derivation of the formula for the relationship between the manufacturing angle of the relieved workpiece W after the free bending and the immersion depth of the upper tool 26 To be received. First, as in shown, based on the position of the workpiece W when bending the formula (b) determined geometrically below.

[Number 2]

[Formula (b)]

• S _t = t + R _d (1 - cos α) + C + R (1 - cos α)

Taking into account the hatched triangle in Furthermore, the formulas (c) and (d) can be derived below. In the formulas (b) to (d), the bending angle (θ) corresponds to the clamping angle.

[Number 3]

[Formula (c)]

• C = (B - tsinα) tanα - tcosα

[Formula (d)]

• B = V / 2 + R _d tan (45 - θ / 4) - Rdsinα - Rsinα
• Further, from the context, α = (180-θ) / 2 in FIG via the relationship A = 2παR / 180 by summarizing formulas (b) to (d) derive the formula (e) below, where R is the inner radius of the Abkantteils on the workpiece and A is the inner arc length of the Abkantteils on the workpiece. This is the top tool 26 with which the workpiece W is loaded, according to the illustration omitted. Further, the workpiece W upon unloading after immersion under the action of the pressing force of the upper tool 26 By spring-back, the deflection in the plastic deformation of the workpiece W to the middle is calculated by means of elastostatic springback calculations to the middle as a degree of balance δ for the springback of the workpiece W, the depth of immersion of the upper tool 26 is deducted. Thus, the bending angle (θ) in the formula (e) can be set equal to the production angle by correction by the compensation amount for the springback δ.

[Number 4]

[Formula (e)]

• R:

  Inner radius of the bending part on the workpiece

  A:

  bend factor

  θ:

  Production angle of the workpiece

  St:

  Immersion depth

  R _d :

  Radius of the support surface of the lower tool

  V:

  Width of the V-opening

  φ:

  Angle of the V-opening

  α:

  (180 - θ) / 2

  δ:

  Compensation dimension for springback of the workpiece

  σ _0.2 :

  Strength of the workpiece

  e:

  E-modulus of the workpiece

The arc length A is in the formula for the arc length of the Abkantteils on the workpiece; however, since the folded part of the finished workpiece W does not correspond to a whole circular arc in practice, A will be referred to as "folding factor (A)" in the following description.

The folding factor (A) is determined by the relationship between the machining conditions for the workpiece W (specifically, the angle (φ) of the V-hole 20 , the width (V) of the V-opening 20 , the material of the workpiece W and the material thickness (t) of the workpiece W) and the production angle of the workpiece W during bending determined. It is in the embodiment 1 in the memory element 38 deposits a Abkantfaktoren data table showing the relationship between the determined by FEM analysis production angle (θ) of the workpiece W and the Abkantfaktor (A) for the respective processing conditions of the workpiece W. Table 2 shows an example of one in the memory element 38 stored edge factor data table; shows an example of a graph for cold rolled steel (SPCC) as part of a storage element 38 stored edge factor data table.

In the computing element 36 So is the Abkantfaktor (A ₁ ), that of the above the adjustment 34 set target production angle (θ ₁ ), based on the input element 32 input machining conditions of the workpiece W from the in the memory element 38 stored Abkantfaktoren data table read out. Then the formula (e) above with A = A ₁ and θ = θ ₁ the target immersion depth (St ₁ ) is calculated. [Table 2] Bending factor data table for θ ₁ = 94 ° t (mm) V (mm) A5052 SPCC SUS304 SUS430 C2801 - 1 / 4H 1.0 6 0.597 1,094 1,261 0,797 1,222 8th 0.622 1,685 1,745 1,208 1,700 10 0,610 2,326 2,242 1.651 2,193 12 0.567 3,006 2,750 2,120 2,698 1.5 8th 0.866 1,366 1,656 1,003 1,600 10 0.915 1,927 2,131 1,395 2,069 12 0.933 2,527 2,617 1,812 2,549 16 0,898 3,822 3,615 2,707 3,540 2.0 10 1,131 1,644 2,052 1,213 1,981 12 1,193 2,188 2,523 1,594 2,444 14 1,230 2,765 3,002 1,996 2,917 18 1,241 4,000 3,984 2,852 3,889

Furthermore, the computing element becomes 36 set so that after input of the measured value for the actual production angle (θ _M ) on the workpiece W after the first-time bending of the workpiece via the input element 32 the target immersion depth (St ₁ ) and the actual production angle (θ _M ) a target immersion depth (St _T ) is calculated, in which an immersion depth of the upper tool 26 according to the target manufacturing angle (θ _T ). Concrete is the computing element 36 adjusted so that the target immersion depth (St _T ) based on the St / θ graph, the relationship between the immersion depth (St) of the upper tool 26 and the production angle (θ) of the workpiece W is calculated so that the slope (f1) of the straight line by measuring point and turning point on the one hand and the slope (f2) of the straight line by turning point and machining point on the other hand in a fixed relationship to each other, wherein the Measuring point is defined by the actual production angle (θ _M ) and the desired immersion depth (St ₁ ), the inflection point by the specified manufacturing angle (θ _F ) and the specified immersion depth (St _F ), with an immersion depth of the upper tool 26 corresponding to the predetermined production angle (θ _F) is obtained, the processing point but by the target production angle (θ _T) and the target immersion depth _(T St), with an immersion depth of the upper tool 26 is achieved according to the target manufacturing angle (θ _T ).

Specifically, the computing element works 36 such that by means of the input element 32 input actual manufacturing angle (θ _M ) of the workpiece W and the target immersion depth (St ₁ ) according to formula (e) above for θ = θ _M and St = St _1, the correction factor (A ') determined based on the correction factor (A' ) and the set production angle (θ _F ) according to formula (e) above for A = A 'and θ = θ _F calculates the specified insertion depth (St _F ), in turn determining the measurement point and inflection point in the St / θ graph and finally the slope (f1) of the straight line is calculated by measuring point and inflection point.

The computing element then determines 36 the slope (f2) of the straight line through the inflection point and the processing point in the St / θ graph such that the slope (f1) of the straight line through the measuring point and inflection point on the one hand and the slope (f2) of the straight line through inflection point and processing point on the other hand in the ratio according to formula (f) below, and calculates the immersion depth according to the via the input element 32 entered target production angle (θ _T ) of the workpiece W on this straight line by inflection point, and processing point with the slope (f2) as a target immersion depth (St _T ), where V is the width of the V-opening 20 of the lower tool 18 and t is the material thickness of the workpiece W. After calculating the target immersion depth (St _T ) via the computing element 36 is used for the bending from the second pass the drive of the tool drive element 28 via the tool drive control 40 of the control unit 30 so controlled that the upper tool 26 exactly with the calculated target immersion depth (St _T ) in the V-opening 20 dips.

[Point 5]

[Formula (f)]

• 4.5 ≤ (f1 / f2) x (V / t) ≤ 6.5

After calculating the target immersion depth (St _T ) via the computing element 36 For the Abkantbearbeitung from the second pass the drive of the tool drive element 28 via the control unit 30 so controlled that the upper tool 26 exactly with the calculated target immersion depth (St _T ) in the V-opening 20 dips. As a result, starting from the second bending operation, a workpiece W can be produced whose final production angle (θ _L ) after folding is in the range -0.25 ° ≤ θ _L -θ _T ≤ 0.25 °.

This also makes it possible for Abkantverfahren, in which the workpiece during immersion of the upper tool 26 in the V-opening 20 of the lower tool 18 at the target manufacturing angle (θ _T ) with the inclined surfaces of the V-hole 20 of the lower tool 18 must be brought into contact, by a single folding of a workpiece W, a target immersion depth (St _T ) calculated corresponding to the target production angle (θ _T ), thereby increasing the number of required Abkantvorgänge the workpiece W, with the production of good parts can be started, significantly reduce and increase productivity. Furthermore, since the bending angle on the workpiece W does not have to be measured during the bending process, general-purpose universal tools can be used without the need for upper and lower tools 18 . 26 Special tools with sensors o. Ä. Would be required, whereby a simple folding of workpieces with the target production angle (θ _T ) is made possible without restrictions on the machinable workpiece shape.

[Example Experiments]

In the following example tests for the bending of workpieces W with the mentioned method and system for bending by means of bending press 10 according to embodiment 1 shown. In these example tests, workpieces W were folded, the angle of the V-opening 20 of the lower tool 18 (φ) with 88 °, the tip angle of the upper tool 26 with 88 ° and the target production angle (θ _T ) of the workpiece W at 90 ° in the input element 32 was entered. On the y-axis in the to are indicated at the position 90 ± 0.25 ° each dash-dot lines; Data within these dash-dot lines show that the folding of the workpiece W was performed with high accuracy (-0.25 ° ≤ θ _L -θ _T ≤ 0.25 °).

(Example 1)

In Example 1, workpieces W were made of aluminum (A5052P) with a material thickness (t) of 1.5 mm, in each case with sub-tools 18 folded, in which the width of the V-opening 20 V = 8 mm, V = 10 mm, V = 12 mm and V = 16 mm. In this first example experiment, in the formula (f) above, (f1 / f2) × (V / t) = 5.0 and θ ₁ -θ _F = 1.5 °. The results of this experiment are in the to and shown in Table 3. [Table 3] f1 / f2 × V / t = 5.0 θ ₁ -θ _F = 1.5 ° t = 1.5 [mm] 1st attempt Second attempt 3. Attempt Immersion depth manufacturing angle Immersion depth manufacturing angle Immersion depth manufacturing angle V = 8 [mm] θ ₁ = 91.98 [°] 1st passage 3,152 91.43 3,152 91.58 3,152 91.57 2nd passage 3,212 90.00 3,218 89.98 3,217 89.97 V = 10 [mm] θ ₁ = 92.60 [°] 1st passage 4,093 92.58 4,093 92.63 4,093 92.68 2nd passage 4,231 90.00 4,234 89.98 4,237 89.97 V = 12 [mm] θ ₁ = 93.08 [°] 1st passage 5,039 92.72 5,039 92.77 5,039 92.88 2nd passage 5,202 90.17 5,206 90.08 5,213 90.05 V = 16 [mm] θ ₁ = 93.60 [°] 1st passage 6,938 94.00 6,938 94.07 6,938 94.07 2nd passage 7,252 89.97 7,259 89.83 7,259 89.98

In the first attempt resulted in a width (V) of the V-opening 20 of the lower tool 18 of 8 mm with the specified production angle (θ _F ) of 90.48 ° calculated from the formula (a) above, as shown in Table 3, a target manufacturing angle (θ ₁ ) of 91.98 ° and a target immersion depth ( St ₁ ) of 3.152 mm. When a workpiece with the desired immersion depth (St ₁ ) of 3.152 mm was bent for the first time, an actual production angle (θ _M ) of 91.43 °, a specified immersion depth (St _F ) of 3.190 mm and a target immersion depth (St _T ) of 3.212 mm. This results in the second bending of the workpiece with the target immersion depth (St _T ) of 3.212 mm for θ _L - θ _{T is} a value of 0; In the second attempt according to the same principle results for θ _L - θ _T a value of -0.02 ° and the third attempt a value of -0.03 °. The immersion depth in Table 3 expresses the value to that of the upper tool 26 when folding actually in the V-opening 20 dips; the same applies to Tables 4 to 10 below.

Next revealed in the first attempt at a width (V), the V-opening 20 of the lower tool 18 of 10 mm with the specified production angle (θ _F ) of 91.10 ° calculated according to the formula (a) above, as shown in Table 3, a target manufacturing angle (θ ₁ ) of 92.60 ° and a target immersion depth ( St ₁ ) of 4.093 mm. The first time that a workpiece was beveled with the desired immersion depth (St ₁ ) of 4.093 mm, an actual production angle (θ _M ) of 92.58 °, a specified immersion depth (St _F ) of 4.172 mm and a target immersion depth (St _T ) of 4,231 mm. This results in the second bending of the workpiece with the target immersion depth (St _T ) of 4.231 mm for θ _L - θ _T a value of 0.

In the second experiment according to the same principle, a value of -0.02 ° results for θ _L - θ _T and a value of -0.03 ° for the third attempt.

Furthermore, in the first experiment, the width of a V (V) was revealed 20 of the lower tool 18 of 12 mm with the specified production angle (θ _F ) of 91.58 ° calculated according to the formula (a) above, as shown in Table 3, a target manufacturing angle (θ ₁ ) of 93.08 ° and a target immersion depth ( St ₁ ) of 5,039 mm. When a workpiece with the desired immersion depth (St ₁ ) of 5.039 mm was bent for the first time, an actual production angle (θ _M ) of 92.72 °, a specified immersion depth (St _F ) of 5.116 mm and a target immersion depth (St _T ) of 5.202 mm. This results in the second bending of the workpiece with the target immersion depth (St _T ) of 5.202 mm for θ _L - θ _T a value of + 0.17 °; In the second experiment according to the same principle, a value of + 0.08 ° results for θ _L - θ _T and a value of + 0.05 ° for the third test.

Further, in the first experiment, the V-opening had a width (V) 20 of the lower tool 18 of 16 mm with the specified production angle (θ _F ) of 92.10 ° calculated according to the formula (a) above, as shown in Table 3, a target manufacturing angle (θ ₁ ) of 93.60 ° and a target immersion depth ( St ₁ ) of 6.938 mm. The first time that a workpiece was machined with the 6.9638 mm target immersion depth (St ₁ ), the actual production angle (θ _M ) was 94.00 °, the insertion depth (St _F ) was 7.130 mm, and the target immersion depth (St _T ) of 7.252 mm. This results in the second bending of the workpiece with the target immersion depth (St _T ) of 7.252 mm for θ _L - θ _T a value of -0.03 °; in the second experiment according to the same principle, a value of -0.17 ° results for θ _L - θ _T and a value of -0.02 ° for the third attempt.

It was thus, as in the to shown, by a single folding of a workpiece W, a target immersion depth (St _T ) according to the target manufacturing angle (θ _T ) calculate and from the second folding of the workpiece by dipping the upper tool 26 in the V-opening 20 realize a high-precision bending with this target immersion depth (St _T ).

(Example 2)

In Example 2, workpieces W were made of aluminum (A5052P) with a defined material thickness (t) of 1.5 mm, 2.0 mm and 3.0 mm with sub-tools 18 folded, in which the width of the V-opening 20 V = 12 mm and V = 16 mm. In this example experiment, in the formula (f) above, (f1 / f2) × (V / t) = 4.5 and θ ₁ -θ _F = 1.5 °. The results of this experiment are in the to and shown in Table 4.

[Table 4]

At a workpiece material thickness (t) of 1.5 mm and a width (V) of the V-opening 20 of the lower tool 18 of 12 mm was obtained with the specified production angle (θ _F ) of 91.58 ° calculated according to the formula (a) above, as shown in Table 4, a target manufacturing angle (θ ₁ ) of 93.08 ° and a target Immersion depth (St ₁ ) of 5.039 mm, which in turn at the first bending of a workpiece an actual production angle (θ _M ) of 92.72 °, a fixed immersion depth (St _F ) of 5.115 mm and a target immersion depth (St _T ) of 5,117 mm resulted. This results in the second bending of the workpiece with the target immersion depth (St _T ) of 5.117 mm for θ _L - θ _T a value of + 0.23 °. Further, at a workpiece material thickness (t) of 2.0 mm and a width (V) of the V-opening 20 of the lower tool 18 of 12 mm in the 1st trial, as shown in Table 4, with the specified production angle (θ _F ) of 90.81 ° a target manufacturing angle (θ ₁ ) of 92.31 ° and a target immersion depth (St ₁ ) of 4,833 mm, which in turn resulted in an actual production angle (θ _M ) of 92.10 °, a specified insertion depth (St _F ) of 4.911 mm and a target immersion depth (St _T ) of 4.948 mm when first bending a workpiece. This results in the second bending of the workpiece with the target immersion depth (St _T ) of 4.948 mm for θ _L - θ _T a value of + 0.08 °; in the second experiment according to the same principle, a value of + 0.05 ° results for θ _L - θ _T.

Further, at a workpiece material thickness (t) of 3.0 mm and a width (V) of the V-hole were found 20 of the lower tool 18 of 16 mm in the 1st trial, as shown in Table 4, with the specified production angle (θ _F ) of 90.48 °, a target manufacturing angle (θ ₁ ) of 91.98 ° and a target immersion depth (St ₁ ) of 6.295 mm, which in turn resulted in an actual production angle (θ _M ) of 92.18, a specified immersion depth (St _F ) of 6.433 mm and a target immersion depth (St _T ) of 6.466 mm when a workpiece was first edged. This results in the second bending of the workpiece with the target immersion depth (St _T ) of 6.466 mm for θ _L - θ _T a value of + 0.08 °; In the second experiment according to the same principle, a value of + 0.12 ° results for θ _L - θ _T.

It was thus, as in the to shown, by a single bending of a workpiece W with (f1 / f2) × (V / t) = 4.5 calculate a target immersion depth (St _T ) according to the target manufacturing angle (θ _T ) and from the second folding of the workpiece by Dipping the upper tool 26 in the V-opening 20 realize a high-precision bending with this target immersion depth (St _T ).

(Example 3)

In Example 3, workpieces W were made of aluminum (A5052P) with a defined material thickness (t) of 1.5 mm and 3.0 mm with sub-tools 18 folded, in which the width of the V-opening 20 V = 12 mm and V = 16 mm. In this example experiment, in the formula (f) above, (f1 / f2) × (V / t) = 6.5 and θ ₁ -θ _F = 1.5 °. The results of this experiment are in the and and shown in Table 5. [Table 5] f1 / f2 × V / t = 6.5 θ ₁ -θ _F = 1.5 ° 1st attempt Second attempt Immersion depth manufacturing angle Immersion depth manufacturing angle V = 12 [mm] θ ₁ = 93.08 [°] t = 1.5 [mm] 1st passage 5,039 92.58 5,039 92.58 2nd passage 5,196 89.78 5,196 89.82 V = 16 [mm] θ ₁ = 91.98 [°] t = 3.0 [mm] 1st passage 6,295 92.18 6,295 92.18 2nd passage 6,481 89.83 6,481 89.98

At a workpiece material thickness (t) of 1.5 mm and a width (V) of the V-opening 20 of the lower tool 18 of 12 mm was found in the first test with the calculated according to the formula (a) above production angle (θ _F ) of 91.58 °, as shown in Table 5, a target manufacturing angle (θ ₁ ) of 93.08 ° and a target immersion depth (St ₁ ) of 5.039 mm, which in turn at the first bending of a workpiece an actual production angle (θ _M ) of 92.58 °, a fixed immersion depth (St _F ) of 5.106 mm and a target immersion depth (St _T ) of 5.196 mm. This results in the second bending of the workpiece with the target immersion depth (St _T ) of 5.196 mm for θ _L - θ _T a value of -0.22 °; in the second attempt on the same principle results in a value of -0.18 °. Further, a workpiece material thickness (t) of 3.0 mm and a width (V) of the V-hole resulted 20 of the lower tool 18 of 16 mm in the first test with the specified production angle (θ _F ) of 90.48 ° calculated according to the formula (a) above, a target production angle (θ ₁ ) of 91.98 ° and a desired immersion depth (St ₁ ) of 6,295 mm, which in turn resulted in an initial production angle (θ _M ) of 92.18 °, a specified insertion depth (St _F ) of 6.433 mm and a target insertion depth (St _T ) of 6.481 mm when first edging a workpiece , This results in the second bending of the workpiece with the target immersion depth (St _T ) of 6.481 mm for θ _L - θ _T a value of -0.17 °; In the second experiment according to the same principle, a value of -0.02 ° results for θ _L - θ _T.

It was thus, as in the and shown; by a single folding of a workpiece W with (f1 / f2) × (V / t) = 6.5 a target immersion depth (St _T ) according to the target manufacturing angle (θ _T ) and calculate from the second folding of the workpiece by immersing the top tool 26 in the V-opening 20 realize a high-precision bending with this target immersion depth (St _T ). From the example experiments 1 to 3, it is apparent that the folding of the workpiece W from the second pass can be performed with high accuracy (-0.25 ° ≤ θ _L -θ _T ≤ 0.25 °) if the value for ( f1 / f2) × (V / t) corresponds to the ratio represented by formula (f).

(4th example experiment)

In Example 4, workpieces W were made of aluminum (A5052P) with a defined material thickness (t) of 1.0 mm and 1.5 mm with sub-tools 18 folded, in which the width of the V-opening 20 V = 12 mm and V = 16 mm. In this example experiment, in the formula (f) above, (f1 / f2) × (V / t) = 3.0 and θ ₁ -θ _T = 1.5 °. The results of this experiment are in the and and shown in Table 6. [Table 6] f1 / f2 × V / t = 3.0 θ ₁ -θ _F = 1.5 ° 1st attempt Second attempt Immersion depth manufacturing angle Immersion depth manufacturing angle V = 12 [mm] θ ₁ = 93.65 [°] t = 1.0 [mm] 1st passage 5,297 93,70 5,297 93.73 2nd passage 5,456 90.98 5,459 91.08 V = 16 [mm] θ ₁ = 93.60 [°] t = 1.5 [mm] 1st passage 6.937 93.75 6.937 94.00 2nd passage 7,169 91.52 7,194 91.12

At a workpiece material thickness (t) of 1.0 mm and a width (V) of the V-hole 20 of the lower tool 18 of 12 mm resulted in the first test with the calculated according to the formula (a) above production angle (θ _F ) of 92.15 °, a target manufacturing angle (θ ₁ ) of 93.65 ° and a target immersion depth (St ₁ ) of 5.297 mm, which, in turn, at the time of first bending a workpiece, has an actual production angle (θ _M ) of 93.70 °, a fixed insertion depth (St _F ) of 5.413 mm and a target immersion depth (St _T ) of 5.456 mm revealed. This results in the second bending of the workpiece with the target immersion depth (St _T ) of 5.456 mm for θ _L - θ _T a value of + 0.98 °; in the second experiment according to the same principle, a value of + 1.08 ° results. The result was a workpiece material thickness (t) of 1.5 mm and a width (V) of the V-opening 20 of the lower tool 18 of 16 mm in the first test with the specified production angle (θ _F ) of 92.10 ° calculated according to the formula (a) above, a target production angle (θ ₁ ) of 93.60 ° and a desired immersion depth (St ₁ ) of 6.937 mm, which in turn gave an actual production angle (θ _M ) of 93.75 °, a fixed immersion depth (St _F ) of 7.103 mm and a target immersion depth (St _T ) of 7.169 mm when the workpiece was first edged , This results in the second bending of the workpiece with the target immersion depth (St _T ) of 7.169 mm for θ _L - θ _T a value of + 1.52 °; In the second experiment according to the same principle, the result for θ _L - θ _{T is} + 1.12 °.

It was thus clear in the experiment that the production angle of the folded workpieces W for (f1 / f2) × (V / t) = 3.0 was less accurate compared to the example tests 1 to 3, and that for a high-precision folding 4 , 5 ≤ (f1 / f2) x (V / t) is advantageous.

(Example 5)

In Example 5, workpieces W were made of aluminum (A5052P) with a defined material thickness (t) of 1.0 mm and 1.5 mm with sub-tools 18 folded, in which the width of the V-opening 20 V = 12 mm and V = 16 mm. In this example experiment, in the formula (f) above, (f1 / f2) × (V / t) = 8.0 and θ ₁ -θ _F = 1.5 °. The results of this experiment are in the and and shown in Table 7. [Table 7] f1 / f2 × V / t = 8.0 θ ₁ -θ _F = 1.5 ° 1st attempt Second attempt Immersion depth manufacturing angle Immersion depth manufacturing angle V = 12 [mm] θ ₁ = 93.65 [°] t = 1.0 [mm] 1st passage 5,297 93,70 5,297 93.65 2nd passage 5.526 88.95 5,523 89.02 V = 16 [mm] θ ₁ = 93.60 [°] t = 1.5 [mm] 1st passage 6.937 93.72 6.937 93.85 2nd passage 7,271 89.57 7,285 89.25

At a workpiece material thickness (t) of 1.0 mm and a width (V) of the V-hole 20 of the lower tool 18 of 12 mm resulted in the first test with the calculated according to the formula (a) above production angle (θ _F ) of 92.15 °, a target manufacturing angle (θ ₁ ) of 93.65 ° and a target immersion depth (St ₁ ) of 5.297 mm, which, in turn, at the time of first bending a workpiece, has an actual manufacturing angle (θ _M ) of 93.70 °, a fixed immersion depth (St _F ) of 5.413 mm, and a target immersion depth (St _T ) of 5.526 mm revealed. This results in the second bending of the workpiece with the target immersion depth (St _T ) of 5.526 mm for θ _L - θ _T a value of -1.05 °; in the second attempt on the same principle results in a value of -0.98 °. The result was a workpiece material thickness (t) of 1.5 mm and a width (V) of the V-opening 20 of the lower tool 18 of 16 mm in the first test with the specified production angle (θ _F ) of 92.10 ° calculated according to the formula (a) above, a target production angle (θ ₁ ) of 93.60 ° and a desired immersion depth (St ₁ ) of 6.937 mm, which yielded an actual production angle (θ _M ) of 93.72 °, a specified insertion depth (St _F ) of 7,100 mm and a target immersion depth (St _T ) of 7.271 mm when a workpiece was first edge-edged. This results in the second bending of the workpiece with the target immersion depth (St _T ) of 7.271 mm for θ _L - θ _T a value of -0.43 °; In the second experiment according to the same principle, the result for θ _L - θ _{T is} -0.75 °.

It was thus clear in the experiment that the production angle of the folded workpieces W for (f1 / f2) × (V / t) 8.0 was less accurate compared to the example tests 1 to 3, and that for a high-precision folding (f1 / f2) × (V / t) ≤ 6.5 is advantageous.

(Example 6)

In the example experiment 6, workpieces W were made of aluminum (A5052P) with a defined material thickness (t) of 1.0 mm, 1.5 mm and 2.0 mm with sub-tools 18 folded, in which the width of the V-opening 20 V = 10 mm and V = 12 mm. In this example experiment, in the formula (f) above, (f1 / f2) × (V / t) = 5.0 and θ ₁ -θ _F = 0.1 °. The results of this experiment are in the to and shown in Table 8. [Table 8] f1 / f2 × V / t = 5.0 θ ₁ -θ _F = 0.1 ° 1st attempt Second attempt Immersion depth manufacturing angle Immersion depth manufacturing angle V = 12 [mm] θ ₁ = 92.25 [°] t = 1.0 [mm] 1st passage 5,402 92.45 5,402 92.53 2nd passage 5,503 90.00 5,505 89.98 V = 10 [mm] θ ₁ = 91.20 [°] t = 1.5 [mm] 1st passage 4,167 90,93 4,167 91.10 2nd passage 4,218 90.18 4,227 89.92 V = 12 [mm] θ ₁ = 90.91 [°] t = 2.0 [mm] 1st passage 4,918 90.45 4,918 90,60 2nd passage 4,950 89.98 4,959 89.92

At a workpiece material thickness (t) of 1.0 mm and a width (V) of the V-hole 20 of the lower tool 18 of 12 mm in the first experiment with the calculated according to the formula (a) above defined production angle (θ _F ) of 92.15 ° a target production angle (θ ₁ ) of 92.25 ° and a target immersion depth (St ₁ ) of 5.402 mm, with which, in turn, when a workpiece is first bent, an actual Production angle (θ _M ) of 92.45 °, a specified immersion depth (St _F ) of 5.425 mm and a target immersion depth (St _T ) of 5.503 mm resulted.

This results in the second bending of the workpiece with the target immersion depth (St _T ) of 5.503 mm for θ _L - θ _T a value of 0 °; in the second attempt according to the same principle results in a value of -0.02 °. The result was a workpiece material thickness (t) of 1.5 mm and a width (V) of the V-opening 20 of the lower tool 18 of 10 mm in the first test with the specified production angle (θ _F ) of 91.10 ° calculated according to the formula (a) above, a target production angle (θ ₁ ) of 91.20 ° and a desired immersion depth (St ₁ ) of 4.167 mm, which in turn resulted in an initial production angle (θ _M ) of 90.93 °, a specified insertion depth (St _F ) of 4.158 mm, and a target immersion depth (St _T ) of 4.218 mm when a workpiece was first edged , This results in the second bending of the workpiece with the target immersion depth (St _T ) of 4.218 mm for θ _L - θ _T a value of + 0.18 °; in the second experiment according to the same principle, for θ _L - θ _T a value of -0.08 ° results. Further, at a workpiece material thickness (t) of 2.0 mm and a width (V) of the V-hole resulted 20 of the lower tool 18 of 12 mm in the first test with the specified production angle (θ _F ) of 90.81 ° calculated according to the formula (a) above, a target production angle (θ ₁ ) of 90.91 ° and a desired immersion depth (St ₁ ) of 4.918 mm, which, in turn, gave an initial production angle (θ _M ) of 90.45 °, a fixed immersion depth (St _F ) of 4.896 mm, and a target immersion depth (St _T ) of 4.950 mm when first edging a workpiece , This results in the second bending of the workpiece with the target immersion depth (St _T ) of 4.950 mm for θ _L - θ _T a value of -0.02 °; in the second experiment according to the same principle, for θ _L - θ _T a value of -0.08 ° results.

It was thus, as in the to shown, by a single bending of a workpiece W with θ ₁ - θ _T = 0.1 ° calculate a target immersion depth (St _T ) according to the target production angle (θ _T ) and from the second folding of the workpiece by dipping the upper tool 26 in the V-opening 20 realize a high-precision bending with this target immersion depth (St _T ).

(Example 7)

In Example 7, workpieces W were made of aluminum (A5052P) with a defined material thickness (t) of 1.0 mm, 1.5 mm and 2.0 mm with sub-tools 18 folded, in which the width of the V-opening 20 V = 6 mm, V = 10 mm and V = 12 mm. In this example experiment, in the formula (f) above, (f1 / f2) × (V / t) = 5.0 and θ ₁ -θ _F = 7.0 °. The results of this experiment are in the to as well as shown in Table 9. [Table 9] f1 / f2 × V / t = 5.0 θ ₁ -θ _F = 7.0 ° 1st attempt Second attempt Immersion depth manufacturing angle Immersion depth manufacturing angle V = 6 [mm] θ ₁ = 97.81 [°] t = 1.0 [mm] 1st passage 2,264 97,40 2,264 96,87 2nd passage 2,479 89.92 2,462 89.92 V = 10 [mm] θ ₁ = 98.10 [°] t = 1.5 [mm] 1st passage 3,808 98.07 3,808 97.98 2nd passage 4,231 90.08 4,225 90,10 V = 12 [mm] θ ₁ = 97.81 [°] t = 2.0 [mm] 1st passage 4,507 97.45 4,507 97,20 2nd passage 4,954 90.00 4,938 90.18

At a workpiece material thickness (t) of 1.0 mm and a width (V) of the V-hole 20 of the lower tool 18 of 6 mm in the first test with the calculated production angle (θ _F ) of 90.81 ° calculated according to the formula (a) above, a target production angle (θ ₁ ) of 97.810 and a target immersion depth (St ₁ ) of 2.264 were obtained mm, which in turn resulted in an actual production angle (θ _M ) of 97.40 °, a specified immersion depth (St _F ) of 2.453 mm and a target immersion depth (St _T ) of 2.479 mm when first bending a workpiece. This results in the second bending of the workpiece with the target immersion depth (St _T ) of 2.479 mm for θ _L - θ _T a value of -0.08 °; The second attempt on the same principle yields a value also -0.08 °. The result was a workpiece material thickness (t) of 1.5 mm and a width (V) of the V-opening 20 of the lower tool 18 of 10 mm in the first test with the specified production angle (θ _F ) of 91.10 ° calculated according to the formula (a) above, a target production angle (θ ₁ ) of 98.10 ° and a desired immersion depth (St ₁ ) of 3.808 mm, which in turn gave an actual production angle (θ _M ) of 98.07 °, a specified immersion depth (St _F ) of 4.171 mm and a target immersion depth (St _T ) of 4.241 mm when first edging a workpiece , This results in the second bending of the workpiece with the target immersion depth (St _T ) of 4.231 mm for θ _L - θ _T a value of + 0.08 °; in the second experiment according to the same principle, a value of + 0.10 ° results for θ _L - θ _T.

Further, at a workpiece material thickness (t) of 2.0 mm and a width (V) of the V-hole resulted 20 of the lower tool 18 of 12 mm in the first test with the specified production angle (θ _F ) of 90.81 ° calculated according to the formula (a) above, a target production angle (θ ₁ ) of 97.81 ° and a desired immersion depth (St ₁ ) of 4,507 mm, which in turn gave an actual production angle (θ _M ) of 97.45 °, a fixed immersion depth (St _F ) of 4.901 mm and a target immersion depth (St _T ) of 4.954 mm when first edging a workpiece , This results in the second bending of the workpiece with the target immersion depth (St _T ) of 4.954 mm for θ _L - θ _T a value of 0 °; in the second experiment according to the same principle, a value of + 0.18 ° results for θ _L - θ _T.

It was thus, as in the to shown, by a single bending of a workpiece W with θ ₁ - θ _T = 7.0 ° calculate a target immersion depth (St _T ) according to the target production angle (θ _T ) and from the second folding of the workpiece by dipping the upper tool 26 in the V-opening 20 with this target immersion depth (St _T ) make a high-precision bending machining in the range -0.25 ° ≤ θ _L - θ _T ≤ 0.25 °.

(Example 8)

In Example 8, workpieces W were made of aluminum (A5052P) with a defined material thickness (t) of 1.0 mm, 1.5 mm and 2.0 mm with sub-tools 18 folded, in which the width of the V-opening 20 V = 12 mm, V = 16 mm and V = 18 mm. In this example experiment, in the formula (f) above, (f1 / f2) × (V / t) = 5.0 and θ ₁ -θ _F = 10.0 °. The results of this experiment are in the to and shown in Table 10. [Table 10] f1 / f2 × V / t = 5.0 θ ₁ -θ _F = 10.0 ° 1st attempt Second attempt Immersion depth manufacturing angle Immersion depth manufacturing angle V = 12 [mm] θ ₁ = 102.15 [°] t = 1.0 [mm] 1st passage 4,695 101.95 4,695 101.75 2nd passage 5,471 91.10 5,455 91.00 V = 16 [mm] θ ₁ = 102.10 [°] t = 1.5 [mm] 1st passage 6,128 102.22 6,128 102.22 2nd passage 7,222 90.38 7,222 90.62 V = 18 [mm] θ ₁ = 101.84 [°] t = 2.0 [mm] 1st passage 6.751 101.82 6.751 101.82 2nd passage 7,941 90.58 7,941 90.63

At a workpiece material thickness (t) of 1.0 mm and a width (V) of the V-hole 20 of the lower tool 18 of 12 mm resulted in the first attempt with the formula (A) calculated above production angle (θ _F ) of 92.15 ° a target production angle (θ ₁ ) of 102.15 ° and a target immersion depth (St ₁ ) of 4.695 mm, which in turn when first folding a Workpiece, an actual manufacturing angle (θ _M ) of 101.95 °, a specified immersion depth (St _F ) of 5.393 mm and a target immersion depth (St _T ) of 5.471 mm. This results in the second bending of the workpiece with the target immersion depth (St _T ) of 5.471 now for θ _L - θ _T a value of + 1.10 °; in the second attempt according to the same principle results in a value of + 1.00 °. The result was a workpiece material thickness (t) of 1.5 mm and a width (V) of the V-opening 20 of the lower tool 18 of 16 mm in the first test with the specified production angle (θ _F ) of 92.10 ° calculated according to the formula (a) above, a target production angle (θ ₁ ) of 102.10 ° and a target immersion depth (St ₁ ) of 6.128 mm, which in turn resulted in an actual production angle (θ _M ) of 102.22 °, a fixed immersion depth (St _F ) of 7.101 mm and a target immersion depth (St _T ) of 7.222 mm when first bending a workpiece. This results in the second bending of the workpiece with the target immersion depth (St _T ) of 7.222 mm for θ _L -θ _T a value of + 0.38 °; In the second experiment according to the same principle, a value of + 0.62 ° results for θ _L - θ _T. Further, at a workpiece material thickness (t) of 2.0 mm and a width (V) of the V-hole resulted 20 of the lower tool 18 of 18 mm in the first test with the specified production angle (θ _F ) of 91.84 ° calculated according to the formula (a) above, a target production angle (θ ₁ ) of 101.84 ° and a desired immersion depth (St ₁ ) of 6.751 mm, which in turn resulted in an actual production angle (θM) of 101.82 °, a specified insertion depth (St _F ) of 7.801 mm and a target immersion depth (St _T ) of 7.941 mm when a workpiece was first edged. This results in the second bending of the workpiece with the target immersion depth (St _T ) of 7.941 mm for θ _L - θ _T a value of + 0.58 °; In the second experiment according to the same principle, the result for θ _L - θ _{T is} + 0.63 °.

It was thus clear in the experiment that the production angle of the bent workpieces W for θ _L - θ _T = 10.0 ° was less accurate compared to the example tests 1 to 3, and that for a high-precision folding 0.1 ° ≤ θ ₁ - θ _F ≤ 7.0 ° is advantageous.

Embodiment 2

In the following, the method and system for bending by means of bending press according to the embodiment 2 will be described. Since the bending press according to Embodiment 2 is the same structure as the bending press described in Example 1 10 , the detailed description is omitted here and instead referenced by like reference numerals to the former.

In the described embodiment 1, the bending factors (A ₁ ) for the individual machining conditions of the workpiece W (specifically: the angle (φ) of the V-hole 20 , the width (V) of the V-opening 20 , the material of the workpiece W and the material thickness (t) of the workpiece W) previously recorded in a database, which is then set as Abkantfaktoren data table to the basis of the input element 32 input machining conditions of the workpiece W the Abkantfaktor (A ₁ ) according to the on the setting 34 set desired production angle (θ ₁ ) read and with the thus read from the Abkantfaktoren data table Abkantfaktor (A ₁ ) the desired immersion depth (St ₁ ), with the upper tool 26 dips when first folding, to calculate. In contrast, in the embodiment 2, the Abkantfaktor (A ₁ ) corresponding to the target production angle (θ ₁ ) is calculated by means of arithmetic approximation, whereby the effort to previously create a Abkantfaktoren data table, and saved in the memory element 38 To be set amount of data can be reduced, while at the same time a wider range of target production angles (θ ₁ ) can be realized and the usability is extended.

As from the in shown relationship between target production angle (θ ₁ ) and Abkantfaktor (A) can be seen, the Abkantfaktor (A) depending on the production angle (θ) of the workpiece W different values; Therefore, in order to increase the accuracy of the target dipping depth (St _T ) determined at the time of first folding, it is desirable to use a target production angle (θ ₁ ) as close as possible to the target production angle (θ _T ).

Further, it can be seen that the fluctuation width of the Abkantfaktors (A) compared to the change of the target manufacturing angle (θ ₁ ) on the workpiece W is low; with decreasing target production angle (θ ₁ ) (ie approaching the value at target immersion depth (St _T )), the Abkantfaktor increasingly approaches a constant value. Here, formula (g) below expresses the approximation formula to the waveform The value for C _t in formula (g) represents the approximate amount of the Abkantfaktors (A ₁ ) corresponding to the target manufacturing angle (θ ₁ ) on the workpiece W. θ _x stands for the largest manufacturing angle, with the workpieces W based of formula (g) (ie for the maximum value of the target production angle), while θ _{y stands} for the production angle, by means of which the folding factor (A ₁ ) is approximated (hereinafter referred to as the approach angle).

[Point 6]

[Formula (g)]

• θ _x:

  maximum production angle with which the workpiece can be folded

  θ _y :

  Approach angle

The maximum production angle with which the workpiece W can be folded (θ _x ) is thus selected in the range θ _F ≤ θ _x ≤ 180 °. Since θ _{x is} the maximum manufacturing angle with which the workpiece W can be folded, a value close to 180 ° is preferred here. The closer the production angle (θ) of the workpiece W is to the specified production angle (θ _F ), the more changes in the folding factor (A) affect the insertion depth of the upper tool 26 , Accordingly, in order to increase the accuracy of approximation, it is preferable to set a value close to the predetermined production angle (θ _F ) for the approximate angle θ _y , which approximates the folding factor (A ₁ ). However, the bending behavior of the workpiece W starts as shown emerges, due to process characteristics when folding, starting from abutment of the workpiece W at the inclined surfaces of the V-opening 20 to change rapidly; therefore, values near the set production angle (θ _F ) are not suitable approximations of the bending factor (A). The proximity angle (θ _y), by which the bend factor (A) is approached, therefore, is preferably selected in the range θ _F <θ _y <θ _x with a range of 95 ° ≤ θ _y ≤ θ _x is particularly preferred.

In this case, the accuracy is increased by choosing a value close to the target production angle (θ _T ), that is, the production angle of the final workpiece W, for θ _y . Embodiment 2 will be described in the case of θ _x = 170 ° and θ _y = 100 °; The approximate value for the bending factor (A1) under these conditions is given as A ₁₀₀ (ie C _t = A ₁₀₀ ).

Here, logarithmic approximation of the in shown relationship between (V / t) and (A ₁₀₀ / V) derive the formula (h) below. In formula (h), d and e represent different material-specific coefficients depending on the workpiece W; the coefficients of exemplary workpieces W for case A ₁₀₀ are shown in Table 11.

[Number 7]

[Formula (h)]

• A ₁₀₀ / V = d × ln (V / t) + e

  d, e:

  material-specific workpiece coefficients

[Table 11] SPCC A5052P SUS304 SUS430 C2801 - 1 / 4H d 0.0967 -0.074 0.00686 0.0622 0.0301 e 0.0061 .2304 0.1902 0.0192 .1464

By combining formula (g) and formula (h), formula (i) can be derived below. The Abkantfaktor (A ₁ ) is thus calculated according to formula (i) below with θ = θ ₁ as approximate value; from the calculated Abkantfaktor (A ₁ ) and the target production angle (θ ₁ ) is then calculated using formula (e), the desired immersion depth (St ₁ ).

[Number 8]

[Formula (i)]

• θ _x:

  maximum production angle with which the workpiece can be folded

  θ _y :

  Approach angle

  d, e:

  material-specific workpiece coefficients

The computing element becomes concrete 36 of the control unit 30 that in the press brake 10 is installed according to Embodiment 2, set so that the Abkantfaktor (A ₁ ) according to the via the adjustment 34 set target production angle (θ ₁ ) according to formula (i) with θ = θ ₁ calculated and the desired immersion depth (St ₁ ) according to formula (e) with A = A ₁ and 0 = 0 _{1 is} calculated, and that at the same time via the input element 32 input actual manufacturing angle (θ _M ) of the workpiece and the target immersion depth (St ₁ ) according to formula (e) with θ = θ _M, the correction factor (A ') determined based on the correction factor (A') and the set production angle (θ _F ) according to formula (e) with A = A 'and θ = θ _F the calculated immersion depth (St _F ) is calculated and based on this the slope (f1) of the straight line is calculated by measuring point and inflection point.

Thus, in the exemplary embodiment 2, the folding factor (A ₁ ) can be calculated in accordance with the target production angle (θ ₁ ) without the bending factors (A ₁ ) for the individual processing conditions of the workpiece W being previously recorded in a database and as the folding factors data table in the storage element 38 must be set. While using a Abkantfaktoren data table by detecting the Abkantfaktoren (A ₁ ) in a database no target manufacturing angle (θ ₁ ) are not included in this Abkantfaktoren data table, can be determined by approximating the Abkantfaktors (A ₁ ) As in Embodiment 2, this limitation of the realizable target production angle (θ ₁ ) cancel and expand the applicability, provided that the condition "target production angle (θ ₁ )> fixed production angle (θ _F )" is met.

Embodiment 3

In the following, the method and system for bending by means of bending press according to the embodiment 3 will be described. Since the bending press according to Embodiment 3 is the same structure as the bending press described in Example 1 10 , the detailed description is omitted here and instead referenced by like reference numerals to the former.

When folding a workpiece W by dipping an upper tool 26 in the V-opening 20 a lower tool 18 guides the machining force (W) when dipping the upper tool 26 in the V-opening 20 for bending of bed 14 , Upper and lower tool 18 . 26 the bending press 10 as well as other plant components. When the tool drive 30 is driven accordingly, so that the upper tool 26 with target immersion depth (St ₁ ) or target immersion depth (St _T ) in the V-opening 20 dips, therefore, arise between the desired immersion depth (St ₁ ) and target immersion depth (St _T ) and the actual immersion depth with which the upper tool 26 in the V-opening 20 dips, deflection-related deviations. In the embodiment 3, a method and system for bending by means of a bending press is described here, in which workpieces W by immersing the upper tool 26 in the V-opening 20 of the lower tool 18 with one around the deflection of the press brake 10 When folding, correct the corrected immersion depth more accurately. In the following description, the deflection of the bending press 10 when folding as "springing of the system (λ)" referred to.

The springing of the system (λ) can be represented by the Hooke's law with λ = W / k, where k is the longitudinal stiffness coefficient of the bending press 10 [kN / mm] and W for the machining force when dipping the upper tool 26 in the V-opening 20 of the lower tool 18 [kN] stands. The springing of the system (λ) is thus determined by the processing force (W). The longitudinal stiffness coefficient (k) is a bend press specific value based on design values of the press brake 10 or can be determined experimentally; the longitudinal stiffness coefficient (k) of the bending press used in Embodiment 3 10 is k = 178.57.

However, it is known that, as in shown when bending a workpiece W in freigebogenem state (ie if the immersion depth (St) of the upper tool 26 does not reach the specified immersion depth (St _F )), the machining force (W) depending on the material of the workpiece W with increasing immersion depth (St) only slightly increases or decreases and remains approximately constant, while bending a workpiece W in contact with the oblique Areas of the V-opening 20 (ie when dipping the upper tool 26 with an immersion depth that corresponds at least to the specified immersion depth (St _F )), the machining force (W) increases rapidly with increasing immersion depth (St).

It could be demonstrated by FEM analysis that when bending a workpiece W in freigebogenem state, the machining force (W) hardly changes even with increasing immersion depth (St) until the production angle (θ) of the workpiece W reaches 135 °. The processing force (W _a ) for the case of "production angle (θ) of the workpiece W ≥ reference production angle (θ _A )" (that is, the case of "submerged depth (St) of the upper tool 26 "Reference immersion depth (St _A )") is known to be expressed by formula (j) below, where θ _{A is} the reference production angle at which the manufacturing angle (θ) of the workpiece W reaches 135 °, and St _{A is} the reference Immersion depth at which with the immersion depth of the upper tool 26 the reference production angle (θ _A ) is reached stands.

In the following description, the machining force (W _a ) in the case of "machining angle (θ) of the workpiece W ≥ reference machining angle (θ _A )" is considered as a reference machining force.

[Point 9]

[Formula (j)]

• k ₁ = -0.055 × V / t + 1.753

  W _a :

  Reference machining force

  k ₁ :

  Coefficient calculated from the ratio between the width of the V-hole of the lower tool and the material thickness of the workpiece

At this time, the relation between the width (V) of the V-hole became 20 of the lower tool 18 and the material thickness (t) of the workpiece W (V / t) on the one hand and the coefficient (k1) on the other hand FEM analyzes performed, the results in are shown. Since based on in the range 5 ≦ V / t ≦ 10, k ₁ = -0.055 × V / t + 1.753 was set as shown in formula (j).

When bending in the range "fixed production angle (θ _F ) ≤ production angle (θ) of the workpiece W ≤ reference production angle (θ _A )" (ie in the case of "reference immersion depth (St _A ) ≤ immersion depth (St) of the upper tool 26 ≤ fixed immersion depth (St _F ) ") arise, as mentioned, with increasing immersion depth (St) of the upper tool 26 slight positive or negative deviations from the reference processing force (W _a ). Since the folding here in the range "fixed production angle (θ _F ) ≤ θ ≤ reference production angle (θ _A )" in free-arc state, the machining force (W) is subject to only minor changes; for the processing force (W) a linear change can be assumed. Therefore, the machining force (W) at the time of folding in the range of "fixed production angle (θ _F ) ≤ θ ≤ reference production angle (θ _A )" can be represented by formula (k) below, where the "fixed machining force (W _f )" of the machining force corresponds to the specified production angle (θ _F ).

In formula (k) k _f stands for the material-specific workpiece coefficient; Coefficients for example workpieces W are shown in Table 12.

[Number 10]

[Formula (k)]

[Table 12] SPCC A5052P SUS304 SUS430 C2801 - 1 / 4H k _f 1.00 0.83 1.17 1.01 1.07

Since during bending in the area "production angle (θ) of the workpiece W ≤ fixed production angle (θ _F )" (ie in the case "fixed immersion depth (StF) ≤ immersion depth (St) of the upper tool 26 ") The workpiece W during the Abkantens with the inclined surfaces of the V-opening 20 is in contact, as in shown, the processing force (W) with increasing immersion depth (St) of the upper tool 26 when increasing above the specified processing force (W _f ) addition to rapidly. shows the measurement results in simulation of the relationship between the material thickness (t) of the workpiece W and k _w / W _a , where k _{w is} the ratio between the increase of the immersion depth (St) and the change of the machining force (W) during bending in the range "fixed Immersion depth (St _F ) ≤ immersion depth (St) of the upper tool 26 "Represents. By logarithmic approximation, the an approximate formula for k _{w was} determined; the machining force (W) for the case of "production angle (θ) of the workpiece W ≤ fixed production angle (θ _F )" can therefore be represented by formula (1) below. In formula (1), k _a and k _{b are} material-specific workpiece coefficients; Coefficients for exemplary workpieces W are shown in Table 13.

[Number 11]

[Formula (1)]

• W = W _f + k _w × (St - St _F )
• k _w = {k _a × ln (t) + k _b } × W _a

  W _a :

  Reference machining force

  k _a , k _b :

  material-specific workpiece coefficients

[Table 13] SPCC A5052P SUS304 SUS430 C2801 - 1 / 4H k _a -6.615 -20.130 -3.726 -6.288 4.326 k _b 9.499 26.842 5,898 10.074 6.868

Due to these relationships, first, the processing force (W) for the production angle (θ) of the workpiece W can be calculated, and the spring-set (λ) for the production angle (θ) of the workpiece W can be determined by the formula (m) shown below.

[Number 12]

[Formula (m)]

• λ = W / k
• i) for θ ≥ θ _A : W = W _a
• ii) for θ _F ≤ θ ≤ θ _A :
  
• iii) for θ ≤ θ _F : W = W _f + k _W × (St - St _F ), in which
  
  k ₁ = -0.055 × V / t + 1.753 W _f = k _f × W _a k _w = {k _a × ln (t) + k _b } × W _a

  θ _A :

  Manufacturing angle for reference machining force; here 135 °

  St _A :

  Immersion depth corresponding to θ _A

  W _a :

  Reference machining force

  k:

  Longitudinal stiffness coefficient of the plant

  σ _B :

  Tensile strength of the workpiece

  ω:

  Folding

  k ₁ :

  Coefficient, which is calculated from the ratio between the width of the V-opening of the lower tool and the material thickness of the workpiece

  k _f, k _a, k _b:

  material-specific workpiece coefficients

At the bending press 10 according to embodiment 3 is the computing element 36 set so that from the set immersion depth (St ₁ ) plus the spring-loaded (λ ₁ ) calculated according to formula (m) with θ = θ ₁ and St = St ₁ , the corrected set immersion depth (St ₁ ') is calculated (St ₁ '= St ₁ + λ ₁ ); it is constructed so that the first bending operation by drive control of the tool drive element 28 via the tool drive control 40 according to the on the computing element 36 calculated corrected desired immersion depth (St ₁ ') takes place. The production angle of the workpiece W after folding with the nominal depth of immersion (St _{1 '} ) corrected by the springing up of the installation (λ ₁ ) during bending with the desired immersion depth (St ₁ ) is thus measured as the actual production angle (θ _M ).

Next is the computing element 36 set so that the corrected target immersion depth (St _T ') is calculated from the target immersion depth (St _T ) plus the system spring (λ _T ) calculated according to formula (m) with θ = θ _T and St = St _T (St _T '= St _T + λ _T ); the bending press is constructed so that the folding from the second pass through drive control of the tool drive element 28 via the tool drive control 40 according to the on the computing element 36 calculated corrected target immersion depth (St _T ') takes place.

By driving the top tool 26 with the nominal immersion depth (St _{1 '} ) corrected for the springing-up of the installation (λ ₁ ) during bending with the desired immersion depth (St ₁ ), the workpiece W can be folded with the actual desired immersion depth (St ₁ ); This makes it possible to increase the bending accuracy when first folding. This, in turn, makes it possible to increase the accuracy of the correction factor (A ') calculated on the basis of desired immersion depth (St ₁ ) and actual production angle (θ _M ) and to increase the machining accuracy from the second pass during the folding operation with this correction factor (A'). Further, by driving the upper tool 26 with the target immersion depth (St _{T '} ) corrected for the springing-up of the installation (λ _T ) during folding with target immersion depth (St _T ), the workpiece W is bent at the actual target immersion depth (St _T ); As a result, the workpiece can be bent precisely with the target production angle (θ _T ).

Embodiment 4

In the following, the method and system for bending by means of bending press according to the embodiment 4 will be described. Since the bending press according to Embodiment 4 is the same structure as the bending press described in Example 1 10 , the detailed description is omitted here and instead referenced by like reference numerals to the former.

The description of the embodiment 4 relates to the folding of a workpiece W by dipping an upper tool 26 with a circular arc-shaped tip in the V-opening 20 a lower tool 18 , In the following description, the radius of curvature at the top of the upper tool becomes 26 referred to as "tip radius R _p " (see ). When folding a workpiece W by dipping an upper tool 26 with an angularly formed shape in the V-opening 20 a lower tool 18 remains the angular edge of the upper tool 26 during the entire bending process on the workpiece W in contact with the deepest part CP on the bending part of the workpiece W (see ); Therefore, the folding takes place exactly with the immersion depth (St) of the upper tool 26 ,

In contrast, it remains true until the inner radius R of the bending part on the workpiece with the tip radius R _{P of} the upper tool 26 the lowest part CP at the bending part of the workpiece W - as with upper tools 26 with an angularly shaped tip - even when dipping an upper tool 26 with a circular arc-shaped tip in the V-opening 20 of the lower tool 18 during the bending process with the tip PE of the upper tool 26 in touch; but as soon as you dive the upper tool 26 in the V-opening 20 of the lower tool 18 the inner radius of the bending part on the workpiece R is less than or equal to the tip radius R _{p of} the upper tool 26 (ie R ≤ R _p ), as in shown, the deepest part CP moves away at the bending part of the workpiece W during bending from the top PE of the upper tool 26 , As soon as the inner radius of the bending part on the workpiece R is less than or equal to the tip radius R _{p of} the upper tool 26 is, arises between the top PE of the upper tool 26 and the deepest part CP at the bending part of the workpiece W a column. When using an upper tool 26 with arcuately formed tip is therefore for bending the workpiece W with the specified production angle (θ) a lower immersion depth (St) of the upper tool 26 required than when using an upper tool 26 with angular shaped tip.

The immersion depth (St) determined according to the formula (e) is the immersion depth (St) of the upper tool 26 in the event that, as with top tools 26 with angularly shaped tip, the tip PE of the upper tool 26 is in contact with the deepest part CP of the bending part on the workpiece W. In the embodiment 4, a method and system for bending by means of bending press is described here, with which when folding a workpiece W with an upper tool 26 with a circular arc-shaped tip in the specified production angle (θ) can achieve a more accurate bending of the workpiece W by the immersion depth (St) determined by formula (e) by the distance corresponding to the between the top PE of the upper tool 26 and the deepest part CP of the bending part on the workpiece W resulting column is compensated. In the following description, the formula (e) determined and fair the folding by means of upper tool 26 Correspondingly corrected immersion depth (St) with radius-formed tip as "radius bending-corrected immersion depth" (St '') and the distance corresponding to the gap between the tip PE of the upper tool 26 and the deepest part CP at the bending part of the workpiece is called "immersion depth deviation" (D).

Here, the relationship between the immersion depth (St) determined according to formula (e), the radius bending-corrected immersion depth (St '') and the immersion depth deviation (D) can be determined geometrically represented by formula (s) below.

[Number 13]

[Formula (s)]

• St ₁ '' = St - D

From the contexts in the triangle OPQ, as in shown, the formula (o) can be derived below, where O is the center of the arc at the top of the upper tool 26 P, the point of intersection between the straight line through the center O perpendicular to the plane of the workpiece W and this plane of the workpiece W, Q is the point of intersection between the straight line along the plane of the workpiece W through the point of intersection P and the vertical line through the center O of the circular arc at the top of the upper tool 26 ,

[Number 14]

[Formula (o)]

• D '= R / cos α - R

From the contexts in the triangle O'P'Q, as in Further, the formula (p) can be derived below, where O 'is the center of the circular arc at the bent portion of the folded workpiece and P' is the intersection between the line drawn from the center O 'perpendicular to the plane of the workpiece W and the plane of the workpiece W; R stands here, as in paragraph [0037], for the inner radius of the bending part on the workpiece.

[Point 15]

[Formula (p)]

From these relationships, the formula (q) shown below can be derived. The relationship α = (180-θ) / 2 shown in paragraph [0037] and the relationship R = 180A / {(180-θ) × π} shown by formula (e) can be set as in Embodiments 1 and 2 , Determine the bending factor (A) according to the manufacturing angle (θ); This allows the immersion depth deviation (D) to correspond to the tip radius (R _p ) of the upper tool 26 and determine the production angle (θ) of the workpiece W and determine the actual immersion depth by inserting into the formula (s), with the upper tools 26 with a circular arc-shaped tip in the V-opening 20 of the lower tool 18 have to dive.

[Paragraph 16]

[Formula (q)]

• D = (R _P -R) × 1-cosα / cosα

The relationship between the immersion depth of the upper tool determined according to formula (n) 26 (ie, the radius bending-corrected immersion depth (St '')) and the production angle (θ) when bending a workpiece W of aluminum (A5052P) with a material thickness (t) of 1.0 mm, a tip radius (R _p ) of the upper tool 26 of 1.0 mm and a width (V) of the V-hole 20 of the lower tool 18 of 6 mm is indicated by the solid line in while the calculated values of the radius bend-corrected immersion depth (St '') determined by FEM analysis are also shown in the graphs in FIG are drawn. From this it is clear that when folding a workpiece W by dipping an upper tool 26 in the V-opening 20 a lower tool 18 with the radius bending-corrected immersion depth (St '') determined according to formula (n), the workpiece W is bent at high accuracy at the specified production angle (θ). This shows the dashed line in the relationship between the immersion depth (St) determined according to formula (e) and the production angle (θ). It can be seen that when folding by means of an upper tool 26 whose tip is circular arc-shaped, by correction by means of subtraction of the immersion depth deviation (D) represented by formula (q) from the immersion depth (St) determined according to formula (e) can achieve a more accurate bending machining of the workpiece W.

At the bending press 10 according to embodiment 4 is the computing element 36 set so that by subtracting the immersion depth deviation (D ₁ ) from the set immersion depth (St ₁ ) determined according to formula (q) with θ = θ _1, the radius bending corrected target immersion depth (St ₁ '') is calculated (St ₁ '') = St ₁ - D ₁ ); it is constructed so that the first bending operation by drive control of the tool drive element 28 via the tool drive control 40 according to the on the computing element 36 calculated radius bending corrected desired immersion depth (St ₁ '') takes place.

The production angle of the workpiece W after folding with the input immersion depth (St ₁ '') corrected by the immersion depth deviation (D ₁ ) during bending with the desired immersion depth (St ₁ ) is thus measured as the actual production angle (θ _M ). Next is the computing element 36 set such that the radius bending-corrected target immersion depth (St _T '') is calculated from the target immersion depth (St _T ) minus the immersion depth deviation (D _T ) calculated with θ = θ _T according to formula (q) (St _T '' = St _T - D _T ); the bending press is constructed so that the folding from the second pass through drive control of the tool drive element 28 via the tool drive control 40 according to the on the computing element 36 calculated radius bending corrected target immersion depth (St _T '') takes place.

By driving the upper tool 26 with the radius bending-corrected set immersion depth (St ₁ ''), in which the immersion depth deviation (D ₁ ) when folding with target immersion depth (St ₁ ) is compensated, the workpiece W with the actual set immersion depth (St ₁ ) can be folded ; This makes it possible to increase the bending accuracy when first folding. This, in turn, makes it possible to increase the accuracy of the correction factor (A ') calculated on the basis of desired immersion depth (St ₁ ) and actual production angle (θ _M ) and to increase the machining accuracy from the second pass during the folding operation with this correction factor (A'). Further, by driving the upper tool 26 with the radius bending-corrected target immersion depth (St _T ''), in which the immersion depth deviation (D _T ) is compensated when folding with target immersion depth (St _T ), the workpiece W with the actual target immersion depth (St _T ) are folded; As a result, the workpiece can be bent precisely with the target production angle (θ _T ).

(Modification Examples)

In the embodiments, cases have been described with a structure in which the bending press on input, setting, computational u. a. has elements; however, the invention is not limited to such examples. By using Abkantverfahren in which the target production angle (θ ₁ ) of the workpiece, which results in bending in freigebogenem state, is set greater than the specified production angle (θ _F ) and in which before the actual folding the workpiece first by immersion an upper tool in the V-opening with a desired immersion depth (St ₁ ) according to this target production angle (θ ₁ ) bent, the actual production angle (θ _M ) measured with the desired immersion depth (St ₁ ) workpiece measured and the target Immersion depth (St _T ) is calculated such that the slope (f1) of the straight line through the measuring point and inflection point in the St / θ graph on the one hand and the slope (f2) of the straight line through inflection point and machining point on the other hand in a fixed ratio to each other, leaves calculate a target immersion depth, which corresponds to the target production angle with a single folding of a workpiece, whereby the number of required At the same time, it is possible to reduce the number of bending operations on the workpiece until the production of good parts can be started, reduce them and increase productivity.

In the exemplary embodiments, the slope of the straight line (f1) by measuring point and inflection point on the one hand and the slope of the straight line (f2) by inflection point and processing point on the other hand, was calculated so that they are in the relationship described by formula (f); however, the invention is not limited to such examples. Depending on the bending accuracy required for the workpiece, this ratio can be in the range (f1 / f2) × (V / t) ≦ 4.5 or in the range 6.5 ≦ (f1 / f2) × (V / t ) to get voted; Thus, the slope of the straight line (f1) by measuring point and inflection point in the St / θ graph and the slope of the line (f2) by inflection point and machining point with a single edge of a workpiece, the target immersion depth can be determined according to the target production angle. Likewise, the desired manufacturing angle (θ ₁ ) may be selected in the range outside 0.1 ° ≤ θ ₁ - θ _F ≤ 7 °, depending on which bending accuracy is required for the workpiece.

In the embodiments, a bevel factor data table showing the relationship between the production angle (θ) of the workpiece and the folding factor (A) for the individual machining conditions of the workpiece (the angle (φ) of the V-opening, the width (V) of the V-axis. Opening, the material of the workpiece and the material thickness (t) of the workpiece), deposited in the storage element; however, it can also, as in shown, derived from the curves for the relationship between the production angle (θ) of the workpiece and the Abkantfaktor (A) for the individual processing conditions of the workpiece approximate formulas and calculated using these approximation formulas on the target manufacturing angle (θ ₁ ) the corresponding Abkantfaktoren (A) ,

LIST OF REFERENCE NUMBERS

18

lower tool

20

V-opening

26

upper tool

32

input element

34

adjustment

36

computing element

38

storage element

40

Tool drive control Target production angle

θ _F

fixed production angle

θ _M

Actual production angle

θ _T

Target production angle

St ₁

Target depth of immersion

St _F

fixed immersion depth

St _T

Target depth of immersion

λ ₁

for θ = θ ₁ and St = St ₁ determined rebound of the system

λ _T

for θ = θ _T and St = St _T determined springing of the system

St ₁ '

Nominal immersion depth (St ₁ ) + spring-loaded system (λ ₁ )

St _T '

Nominal immersion depth (St _T ) + spring-deflection of the system (λ _T )

D ₁

Immersion depth deviation for θ = θ ₁

D _T

Immersion depth deviation for θ = θ _T

St ₁ ''

Nominal immersion depth (St ₁ ) - Immersion depth deviation (D ₁ )

St _T ''

Nominal immersion depth (St _T ) - Immersion depth deviation (D _T )

f1

Slope of the straight line through the measuring point and inflection point

f2

Slope of the line through inflection point and processing point

W

workpiece

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• JP 2002-79319 A [0004]

Claims (14)

Bending method by means of a bending press, characterized in that by dipping an upper tool in the V-opening of the lower tool under this upper tool and touching the workpiece with the inclined surfaces of the V-opening of this lower tool, the workpiece is bent so that its production angle to set Target production angle (θ _T ) corresponds; while the target production angle (θ ₁ ) of the workpiece, which is achieved in canting in freigebogenem state, set greater than the predetermined manufacturing angle (θ _F ) of the workpiece after discharge on contact of the workpiece with the inclined surfaces of the V-opening; the workpiece is bent by immersing the upper tool in the V-opening with a desired immersion depth (St ₁ ) corresponding to this target production angle (θ ₁ ) and the actual production angle (θ _M ) of the desired immersion depth (St ₁ ) bent workpiece measured; from the St / θ graph, which shows the relationship between the immersion depth (St) of the upper tool and the production angle (θ) of the workpiece, the target immersion depth (St _T ) for the folding is calculated so that the slope (f1) the straight line through the measuring point and turning point on the one hand and the slope (f2) of the straight line through the turning point and the machining point on the other hand are in fixed relation to each other; In this case, the measuring point is defined by the actual production angle (θ _M ) and the desired immersion depth (St ₁ ), the inflection point by the specified manufacturing angle (θ _F ) and the specified immersion depth (St _F ), with an immersion depth of the upper tool accordingly the set production angle (θ _F ) is achieved; on the other hand, the machining point is defined by the target machining angle (θ _T ) and the target immersion depth (St _T ) with which an insertion depth of the upper tool is achieved according to the target machining angle (θ _T ). Method for bending by means of bending press according to claim 1, characterized in that the target immersion depth (St _T ) is calculated so that the slope (f1) of the straight line by measuring point and inflection point on the one hand and the slope (f2) of the straight line by inflection point and processing point on the other hand, in the relationship described by formula (f) below, where (V) is the width of the V-hole of the lower die, and (t) is the material thickness of the workpiece. [Number 5] [Formula (f)] 4.5 ≤ (f1 / f2) x (V / t) ≤ 6.5 Method for bending by means of bending press according to one of claims 1 and 2, characterized in that a defined by the machining conditions of the workpiece and the production angle (θ) of the workpiece Abkantfaktor (A ₁ ) based on the target manufacturing angle (θ ₁ ) determined and the target Immersion depth (St ₁ ) according to formula (e) below with A = A ₁ and θ = θ _{1 is} calculated; after the workpiece has been bent with this desired immersion depth (St ₁ ), the correction factor (A ') with θ = θ _M is determined by the desired immersion depth (St ₁ ) and the actual production angle (θ _M ) according to formula (e) below calculated; then the specified immersion depth (St _F ) is calculated using the correction factor (A ') and the specified production angle (θ _F ) according to formula (e) below with A = A' and θ = θ _F ; Based on this immersion depth, the slope (f1) of the straight line is again calculated by measuring point and inflection point. [Paragraph 4] [formula (e)]

R: Inner radius of the bending part on the workpiece A: Bending factor θ: Work piece manufacturing angle St: Immersion depth R _d : Radius of the lower tool support surface V: V hole width φ: V hole angle α: (180 - θ) / 2 δ: compensation value for springback of the workpiece σ _0.2 : strength of the workpiece E: modulus of elasticity of the workpiece Bending method by means of bending press according to claim 3, characterized in that the bending factor (A ₁ ) according to formula (i) below with θ = θ _{1 is} calculated. [Number 8] [Formula (i)]

θ _x : maximum production angle with which the workpiece can be folded θ _y : approximation angle d, e: material-specific workpiece coefficients Method for bending by means of bending press according to one of claims 3 and 4, characterized in that the Abkantwinkel of the workpiece after folding with the corrected target immersion depth (St ₁ '), resulting from the desired immersion depth (St ₁ ) plus the after Formula (m) below with θ = θ ₁ and St = St ₁ composed spring deflection of the plant (λ ₁ ) composed, as actual production angle (θ _M ) is measured; then the workpiece with the corrected target immersion depth (St _T '), which is calculated from the target immersion depth (St _T ) plus the spring deflection of the system calculated according to formula (m) below with θ = θ _T and St = St _T ( λ _T ), folded. [Number 12] [Formula (m)] λ = W / k i) for θ ≥ θ _A : W = W _a ii) for θ _F ≤ θ ≤ θ _A :

iii) for θ ≤ θ _F : W = Wf + k _W × (St - St _F ), in which

k ₁ = -0.055 × V / t + 1.753 W _f = k _f × W _a k _w = {k _a × ln (t) + k _b } × W _a θ _A : manufacturing angle for reference machining force; here 135 ° St _A : Immersion depth corresponding to θ _A W _a : Reference machining force k: Longitudinal rigidity coefficient of the installation σ _B : tensile strength of the workpiece ω: bending length k ₁ : coefficient calculated from the ratio between the width of the V-hole of the lower tool and the material thickness of the workpiece k _f , k _a , k _b : material-specific workpiece coefficients Bending method by means of a bending press according to one of claims 3 to 5, characterized in that during folding of workpieces by means of an upper tool whose tip is arcuate, the Abkantwinkel the workpiece after folding with the radius bending corrected target immersion depth (St ₁ '') which is composed of the desired immersion depth (St ₁ ) minus the immersion depth deviation (D ₁ ) calculated below according to formula (q) below with θ = θ ₁ , is measured as the actual production angle (θ _M ); then the workpiece is bent with the radius bending corrected target immersion depth (St _T ''), which is calculated from the target immersion depth (St _T ) minus the immersion depth deviation (D _T ) calculated according to formula (q) below with θ = θ _T , [Paragraph 16] [Formula (q)] D = (R _P -R) × 1-cosα / cosα Method for bending by means of bending press according to one of claims 1 to 6, characterized in that the target manufacturing angle (θ ₁ ) in the range of 0.1 ° ≤ θ ₁ - θ _F ≤ 7 ° is set. System for bending by bending press, characterized in that this system for bending by bending press on an upper tool, a lower tool lying under this upper tool with V-opening and a tool drive element, with which the upper tool or lower tool is driven so that the upper tool is immersed in the V-hole, the workpiece contacts the inclined surfaces of the V-hole when the upper tool is dipped in the V-hole by driving with the tool drive member, and the machining angle of the workpiece during the trimming corresponds to the set target machining angle (θ _T ); this system has an inputting element for inputting both the machining conditions and the target machining angle (θ _T ) of the workpiece and the measured actual machining angle (θ _M ) of the workpiece via an adjusting member with that of the input member input processing conditions and the target production angle (θ _T ) on the workpiece of the target manufacturing angle (θ ₁ ) of the workpiece is set to be greater than the predetermined manufacturing angle (θ _F ) of the workpiece after discharge on contact of the workpiece with the inclined surfaces of the V-opening , via a computing element, with which the desired immersion depth (St ₁ ) is calculated so that an immersion depth of the upper tool according to the set via the setting target manufacturing angle (θ ₁ ) results, and with the reference to this desired immersion depth (St ₁ ) and the input via the input actual manufacturing angle (θ _M ) the target immersion depth (S t _T ) is calculated so that an immersion depth of the upper tool according to the target production angle (θT) results; as well as via a drive control element with which the drive is controlled by the tool drive element so that the upper tool dives into the V-opening in accordance with the calculated via the computing element target immersion depth (St ₁ ) or target immersion depth (St _T ); the computing element is set to calculate a target immersion depth (St _T ) at which the slope (f1) of the straight line through the measurement point and inflection point on the one hand and the slope (f2) the straight line through the turning point and the machining point are on the other hand in a fixed relationship to each other; Here, in the St / θ graph showing the relationship between the immersion depth (St) of the upper tool and the manufacturing angle (θ) of the workpiece, the measuring point is defined by the actual manufacturing angle (θ _M ) and the target immersion depth (St ₁ ), the inflection point by the set production angle (θ _F ) and the set immersion depth (St _F ), with which an immersion depth of the upper tool is achieved according to the set production angle (θ _F ); on the other hand, the machining point is defined by the target machining angle (θ _T ) and the target immersion depth (St _T ) at which an insertion depth of the upper tool is achieved in accordance with the target machining angle (θ _T ); First, by driving control of the tool drive element via the drive control element is folded once according to the calculated by the computing element target immersion depth (St ₁ ); After this first bending operation, starting from the second bending operation, by driving control of the tool driving member via the drive control element according to the target immersion depth (St _T ) generated by the computing element from the actual manufacturing angle (θ _M ) of the workpiece and the target immersion depth entered via the input element (St ₁ ) was calculated, folded. System for bending by means of bending press according to claim 8, characterized in that the computing element is set accordingly, so that the target immersion depth (St _T ) is calculated so that in the St / θ graph, the slope (f1) of the straight line through measuring point and Turning point on the one hand and the slope (f2) of the straight line by turning point and machining point on the other hand in the relationship defined by the formula (f) below, where (V) is the width of the V-opening of the lower tool and (t) the material thickness of the workpiece , [Number 5] [Formula (f)] 4.5 ≤ (f1 / f2) x (V / t) ≤ 6.5 Bending press bending system according to one of Claims 8 and 9, characterized in that this system has a storage element in which a folding factor data table is stored, which determines the relationship between the production angle (θ) of the work piece and the machining conditions and Manufacturing angle (θ) of the workpiece calculated Abkantfaktor (A) shows; In this case, the computing element is set so that the Abkantfaktor (A ₁ ) read out according to the set via the setting target manufacturing angle (θ ₁ ) based on the input via the input processing conditions of the workpiece from the stored in the memory element Abkantfaktoren data table and the desired immersion depth (St ₁ ) is calculated according to the formula (e) below with A = A ₁ and θ = θ ₁ and based on the input via the input actual working angle (θ _M ) of the workpiece and the desired immersion depth (St ₁ ) of the correction factor (A ') according to the formula (e) below with θ = θ _M , based on the correction factor (A') and the set production angle (θ _F ) according to the formula (e) below with A = A 'and θ = θ _F the specified immersion depth (St _F ) is calculated and based on this, the slope (f1) of the straight line is calculated by measuring point and inflection point. [Paragraph 4] [formula (e)]

R: Inner radius of the bending part on the workpiece A: Bending factor θ: Workpiece manufacturing angle St: Immersion depth R _d : Radius of the lower tool support surface V: V-hole width φ: V-hole angle α: (180 - θ) / 2 δ : Compensation amount for springback of the workpiece σ _0.2 : Strength of the workpiece E: E-modulus of the workpiece System for folding by means of bending press according to one of claims 8 and 9, characterized in that the computing element is set so that the Abkantfaktor (A ₁ ) according to the set via the setting target manufacturing angle (θ ₁ ) according to the formula (i) below is calculated with θ = θ ₁ and the target immersion depth (St ₁ ) is calculated according to the formula (e) below with A = A ₁ and θ = θ ₁ and based on the entered via the input element actual production angle (θ _M ) of the workpiece and the target immersion depth (St ₁ ) according to the formula (e) below with θ = θ _M, the correction factor (A ') determined based on the correction factor (A') and the set production angle (θ _F ) according to the formula (e) at the bottom with A = A 'and θ = θ _F the calculated immersion depth (St _F ) is calculated and based on this the slope (f1) of the straight line is calculated by measuring point and inflection point. [Paragraph 4] [formula (e)]

R: Inner radius of the bending part on the workpiece A: Bending factor θ: Workpiece manufacturing angle St: Immersion depth R _d : Radius of the lower tool support surface V: V-hole width φ: V-hole angle α: (180 - θ) / 2 δ : Compensation amount for springback of the workpiece σ _0.2 : Workpiece strength E: E modulus of the workpiece [Number 8] [Formula (i)]

θ _x : maximum production angle with which the workpiece can be folded θ _y : approximation angle d, e: material-specific workpiece coefficients System for bending by means of bending press according to one of claims 10 and 11, characterized in that the computing element is set so that from the desired immersion depth (St ₁ ) plus that according to the formula (m) below with θ = θ ₁ and St = St ₁ determined spring deflection of the plant (λ ₁ ) the corrected target immersion depth (St ₁ ') calculated and from the target immersion depth (St _T ) plus the according to this formula (m) with θ = θ _T and St = St _T determined Spring deflection of the system (λ _T ) the corrected target immersion depth (St _T ') is calculated, and is constructed so that initially only by drive control of the tool drive element via the drive control element according to the calculated by the computing element corrected target immersion depth (St ₁ ') bent and from the second bending operation by drive control of the tool drive element via the drive control element according to the calculated by this computing element corrected target immersion depth (St _T ') is folded. [Number 12] [Formula (m)] λ = W / k i) for θ ≥ θ _A : W = W _a ii) for θ _F ≤ θ ≤ θ _A :

iii) for θ ≤ θ _F : W = W _f + k _W × (S _t - St _F ), in which

k ₁ = -0.055 × V / t + 1.753 W ₁ = k _f × W _a k _w = {k _a × ln (t) + k _b } × W _a θ _A : manufacturing angle for reference machining force; here 135 ° St _A : immersion depth corresponding to θ _A W _a : reference machining force k: longitudinal stiffness coefficient of the plant σ _B : tensile strength of the workpiece ω: bending length k ₁ Coefficient, which is the ratio between the width of the V-hole of the lower tool and the Material thickness of the workpiece calculates k _f , k _a , k _b : material-specific workpiece coefficients System for folding by means of bending press according to one of claims 10 to 12, characterized in that the tip of the upper tool is circular arc-shaped, and the computing element is set so that the radius bending corrected target immersion depth (St ₁ ''), resulting from the target Immersion depth (St ₁ ) minus the immersion depth deviation (D ₁ ) determined according to formula (q) below with θ = θ ₁ , and the radius bend corrected target immersion depth (St _T '') resulting from the target immersion depth (St _T ) minus the immersion depth deviation (D _T ) determined according to this formula (q) with .theta. =. theta. _T , and is constructed such that first of all by drive control of the tool drive element via the drive control element according to the radius bending-corrected desired immersion depth calculated by the computation element Be bent (St ₁ '') and from the second bending operation by drive control of the tool drive element over r is the drive control element, according to the calculated by this computing element radius bending corrected target immersion depth (St _T '') is folded. [Paragraph 16] [Formula (q)] D = (R _P -R) × 1-cosα / cosα A bending press bending system according to any one of claims 8 to 13, characterized in that the target manufacturing angle (θ ₁ ) is set via the adjusting member in the range of 0.1 ° ≤ θ ₁ -θ _F ≤ 7 °

Images