JP2000140943A - Calculating method of material attribute, folding method and its device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bent product excellent in bending accuracy by effecting the trial bending to a test piece formed of a same material as that of a blank to obtain the attribute of the test piece itself, and effecting the bending based on the obtained attribute. SOLUTION: A folding device is provided with position sensors 23L, 23R to detect the relative positional relationship of a punch P and a die D, pressure sensors 17L, 17R to detect the reduction in load, a folding angle detecting device when a work is folded by the punch and the die in cooperation with each other, a folding angle measuring device 30 to measure the finish angle, a material attribute operating means which effects the trial bending using a test piece cut from a work body from which the blank is taken, or the test piece cut from a work rod, and operates the material attribute based on the factors in the trial bending, and a working condition determining means to determine the working condition for blank using the material attribute obtained by the material attribute operating means in the operation for folding the blank.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring a material attribute, a bending method, and an apparatus therefor.

[0002]

2. Description of the Related Art Conventionally, in order to obtain a target angle when a workpiece is bent, an existing calculation formula is based on work conditions (material, plate thickness, bending length, tensile strength), mold conditions, and the like. First, the relative distance (D value) between the punch and the die was calculated and bending was performed.

[0003]

However, since the work (material) to be processed has different characteristics depending on the material maker, rod, and plate thickness, bending is performed with the D value obtained under the same conditions. However, it does not reach the target angle. Moreover, even if vinyl is applied or painted on the surface of the work, the characteristics of the work itself are different, and D
Even if bending is performed with the value, the target angle will not be achieved.

[0004] For this reason, there has been a problem that it is necessary to carry out trial bending many times, and the number of trial bending is further increased under unknown processing conditions. As a result, the material cost is increased and there is a time until the D value for obtaining the target angle is obtained, and it has been difficult to efficiently perform the bending process in terms of time and cost.

An object of the present invention is to perform test bending on a test piece made of the same material as a blank to obtain the attributes of the test piece itself, and to set bending conditions based on the obtained attributes to perform bending. Accordingly, it is an object of the present invention to provide a method for calculating a material attribute, a bending method, and a device therefor, which can obtain a bent product having good bending accuracy.

[0006]

According to a first aspect of the present invention, there is provided a method for measuring a material attribute, comprising cutting out a test piece from the same material as a blank, and obtaining various data upon trial bending of the test piece. Is used to determine a Young's modulus, an n-th power index, and a plasticity coefficient.

Therefore, a test piece is cut out from the same material as the blank, and a test bending is performed on the cut out test piece. The Young's modulus, n-th power index, and plasticity coefficient are obtained based on various data at the time of trial bending, such as target angle information, required tonnage information, stroke information, mold information, and springback information.

According to a second aspect of the present invention, a test piece is cut from a work body or a work rod from which a blank is cut, and test bending is performed using the test piece. Then, a material attribute is obtained, and the obtained material attribute is used for an operation for bending the blank, and a bending machine is controlled to perform a bending process on the work.

According to a third aspect of the present invention, there is provided a bending method according to the second aspect, wherein the various coefficients are target angle information, required tonnage information, stroke information, mold information, springback. In addition to the information, the material attributes are a Young's modulus, an n-th power index, and a plasticity coefficient.

According to a fourth aspect of the present invention, there is provided a bending apparatus comprising: a position sensor for detecting a relative positional relationship between a punch and a die; a pressure sensor for detecting a decrease in load; A bending angle detection device that detects the bending angle when the work is bent, a bending angle measurement device that measures the finished angle after bending, and a work body or work rod that cuts a blank A test bending is performed using the cut test piece, and a material attribute calculating means for calculating a material attribute based on various coefficients at the time of the test bending; And a processing condition determining means for determining a blank processing condition by using the calculation for the calculation.

Therefore, in the bending method and apparatus according to the second and third aspects of the present invention, a test piece is cut from a work body or a work rod, and the test piece is subjected to trial bending. Coefficients at the time of this test bending, such as target angle information, required tonnage information, stroke information, mold information, springback information, and various values detected by the position sensor, pressure sensor, bending angle detecting device, and bending angle measuring device Based on the detected value, Young's modulus, n-th power index, and plasticity coefficient are obtained as material attributes by a material attribute calculating means.

The processing conditions for blanks are determined by the processing condition determining means by using these various material attributes obtained by the material attribute calculating means in a calculation for bending the test piece from the same material to obtain a blank. When the bending machine is controlled according to the processing conditions and the work is bent, a bent product with good bending accuracy can be obtained.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings.

First, the bending apparatus will be described.
Referring to FIG. 1, a press brake 1 as a bending device includes C-shaped frames 3L and 3R that are erected, and a lower table that can move up and down is provided on the lower front surface of the C-shaped frames 3L and 3R. 5 are provided. A die D is detachably mounted on the lower table 5. On the other hand, an upper table 7 is fixedly provided on the upper front surface of the C-shaped frames 3L and 3R, and a punch P is detachably mounted below the upper table 7.

Main cylinders 9L, 9R are provided below the C-shaped frames 3L, 3R, and piston rods 11 mounted on the main cylinders 9L, 9R are provided.
The tips (upper ends) of L and 11R are attached to the lower table 5. The lower table 7 has built-in crowning sub-cylinders 13L and 13R, and is mounted on the upper part of the lower table 7 via piston rods 15L and 15R.

The main cylinder 9L and the sub cylinder 1
Pressure-reducing valves 15L and 15R are connected to the main cylinder 9L and the sub-cylinder 13R, and the pressure sensors 17L and 17R are connected to the main cylinders 9L and 9R.
Is connected. Position scales 19L and 19R are provided on both sides of the upper table 7, and brackets 21L and 2R are provided on both sides of the lower table 5.
Position sensors 23L and 23R are provided via 1R.

Further, a guide rail 25 is laid on the upper front surface of the lower table 5, and a bending angle measuring device for detecting a bending angle when the work is bent is provided on the guide rail 25. 27 is provided movably in the left-right direction. This bending angle measuring device 2
7, pressure sensors 17L, 17R, position sensors 23L, 2
3R are connected to the control device 29, respectively. Also,
A bending angle measuring device 30 for measuring a finished bending angle when a work is bent is provided.

Referring to FIG. 2, a slider 31 is provided on the guide rail 25 so as to be movable and positioned in a direction perpendicular to the plane of FIG. A bracket 33 is attached to the slider 31 with a plurality of bolts, and a guide rail 35 is provided on the bracket 33 in the front-rear direction (the left-right direction in FIG. 2). A slider 37 is provided that is movable along the guide rail 35 in the front-rear direction. A measurement indicator 39 is provided on the slider 37.

The measurement indicator 39 has a detection head 41, and the detection head 41 is
Is supported so as to integrally rotate with the gear 43 having a rotation center P ₀ on the front center of the 1. The gear 43
A worm gear 45 that meshes with the worm gear 45 is rotatably provided, and the worm gear 45 is driven to rotate by a motor 47.

Therefore, when the motor 47 rotates the worm gear 45, the gear 4 meshed with the worm gear 45
3 is driven to rotate, so that the detection head 41 is moved up and down by a desired angle around the center of the front surface (up and down direction in FIG. 2).
Rocked.

Referring to FIG. 3, the detection head 41
Has a laser projector 49 as a light emitting element at a central portion, and a first light receiver 51A and a second light receiver 51, which are composed of, for example, photodiodes, above and below the laser light projector 49.
B.

Next, the principle of detecting the bending angle 2 · θ of the work W using the above-described detection head 41 will be described.

Referring to FIG. 4, the swinging detection head 4
The laser beam LB emitted from the first laser projector 49 is
The light is reflected by the surface of the work W, received by the first light receiver 51A and the second light receiver 51B, converted into a signal, and transmitted to the control device 29. That is, when the control device 29 rotates to the position where the angle of the detection head 41 becomes θ ₁ , the laser light LB emitted from the laser projector 49 is reflected by the work W and received by the first light receiver 51A. It can be seen that the amount of reflected light is maximized.

FIG. 5 shows a change in the amount of reflected light received with respect to the rotation angle of the detection head 41. That is,
Generally, the rotation angle of the detection head 41 is equal to the reference angle θ (FIG. 4).
(In the example shown in FIG. 5, θ = 0 degrees), the amount of light received by the first light receiver 51A becomes maximum when rotated counterclockwise by θ ₁ degree, and the detection head 41 It can be seen that the amount of light received by the second light receiver 51B is maximized when the rotation angle of is rotated clockwise by θ ₂ degrees with respect to the reference angle θ.

First light receiver 51A and second light receiver 51B
Are provided at the same distance from the laser projector 49, the angle of the detection head 41 when the amount of light received by the first light receiver 51A is maximum in FIG. 5 and the amount of light received by the second light receiver 51B are maximum in FIG. The laser beam LB from the laser projector 49 at an intermediate position with respect to the angle of the detection head 41
It can be seen that light is projected perpendicularly to the bent workpiece W. Accordingly, the angle 2θ of the bent work W is 2 ·
It can be obtained from θ = θ ₁ + θ ₂ .

As shown in FIG. 6, the control device 29 includes a CPU 53, and an input device 55 such as a keyboard for inputting various data is connected to the CPU 53. A display device 57 such as a CRT for displaying various data is connected. The CPU 53 includes main cylinders 9L, 9R,
Pressure sensors 17L, 17R, position sensors 23L, 23R
And the measurement indicator 39 are connected.

As shown in FIG. 7 (A), the CPU 53 receives the punch tip radius PR, the punch tip angle PA, the punch tip slope length PL, and the punch deflection constant PT from the input device 55 as mold conditions. FIG. 7 (B)
As shown in the figure, data such as die shoulder radius DR, die groove angle DA and die V width V, and material conditions such as material, plate thickness T, bending length B, friction coefficient μ, and tentative target angle A ′ Is stored in the memory 59 in which is input and stored. Further, the temporary D value to CPU 53, as shown in the first computation means 61 and 8 for calculating the temporary spring-back amount [Delta] [theta] ', the blank W _B test piece was cut from the same material W and W _T When the bending is performed at the sandwiching angle A1 with the press brake 1 shown in FIG. 1, the pressure sensors 17L and 17R and the position sensors 23L and 23
A relation file 63 between the actual bending load and the distance between the blades, which stores the curve of the relation between the actual bending load and the distance between the blades shown in FIG. 9 based on the detection value detected by R, is connected.

Further, the CPU 53 has second computing means (material attribute computing) for computing material attributes such as Young's modulus, n-th power index, and plasticity coefficient when the load is gradually unloaded after bending at the sandwiching angle A1. means) 65 and, comparative determination unit 67 for comparing the various data and determines the second bending during processing conditions of the material attributes based on the blank W _B, such as Young's modulus obtained by the calculation means 65 process The condition determining means 69 are connected respectively.

With the above configuration, FIG. 10, FIG. 11, and FIG.
And based on the flowchart shown in FIG. 13, the operation will be described for calculating the bending test piece W _T Try bending performs material properties used when the blank W _B.

[0030] In FIG. 10, in step S1, when performing a trial bending the test piece W _T cut from the same material W shown in FIG 8, shows the input device 55 in FIG. 7 (A) as a mold condition The punch tip radius PR of the punch P, the punch tip angle PA, the punch tip slope length PL,
The punch deflection constant PT, the die shoulder R of the die D, the die V groove angle DA, the die V width V, and the temporary target angle A 'as shown in FIG. 7B are input and temporarily stored in the memory 59. In step S2, the temporary D
Calculate the value or the temporary springback amount Δθ ′.

In step S3, the mold condition, material condition, temporary target angle A 'and temporary D value obtained by the first calculating means 61, or temporary scissor angle (A'-. DELTA..theta. ') Are stored in the memory 59. ) was determined processing conditions bending try incorporated into the processing condition determining means 69 performs test bending test piece W _T with this determined processing conditions. In step S4 is determined by the angle measuring device 30 to bend the finishing angle A0 of the test piece W _T was tried bent.

In step S5, (1), stroke-
Load continuous information (including data up to the time of unloading),
(2), stroke-scissor angle continuous information, (3), final scissor angle A1, (4), final stroke S1,
(5) The actual machine processing information of the final load P1 is read. Then, in step S6, the processing of the actual machine processing information is performed, and (1) 'the distance between the blades-the actual bending load as shown in FIG.
(2) 'inter-blade distance-scissor angle, (3)' final interleaving angle A1, (4) 'final inter-blade distance S2, (5)' final actual bending load, (6) 'measured springback amount θ1 = A
0-A1 is determined.

Next, a comparison operation means 69 determines whether or not step S7 is air bend or bottoming processing. That is, from the information of (1) ′ which is a curve of the relationship between the blade distance and the actual bending load filed in FIG. 9, the load gradient near the final load is as shown in FIG. 14 (A). If so, it is determined to be air bend, and if the state is as shown in FIG. 14B, it is determined to be bottoming.

If it is determined in step S7 that the air bend has occurred, the process proceeds to step S8 in the flowchart of FIG. 11, where an n value (n-th power curing index) is assumed. In step S9, the calculation of the winding angle φ1 around the punch tip radius PR is performed by the second calculating means 65, where φ1 = f (A
1, μ, PR, T, V, DR, DA, with performed from the equation of n), the n and φ1 in step S10 the calculation of the theoretical blade distance S _t as shown in FIG. 15 the second computing means 65
And _St = f (V, DR, DA, A1, φ1, μ, P
R, T). In step S11 and the theoretical blade distance S _t and the actual blade spacing S2 are compared, until S _t = S2 returns to before the step S8, the process proceeds to step S12 becomes a S _t = S2, n value is determined Is done.

In step S13, an F value (plastic coefficient) is assumed. In step S14, the calculation of the theoretical bending load P
P = f (n, B, F, T, A1, μ,
V, DR, DA, φ1, PR). In step S15, the logical bending load P and the actual bending load P2 are compared, and the process returns to step S13 until P = P2. When P = P2, the process proceeds to step S16, and the F value is determined.

In step S17, the second arithmetic means 65 calculates the Young's modulus (E value) from the measured springback amount Δθ1.
And E = f (B, F, T, n, PR, φ1, V, DR, D
A, A1, μ, Δθ1). Step S
At 18 the E value is determined.

Therefore, steps S8 to S1
N value of the material attributes used in air Bend 8, F value and E values are calculated, the blank W _B of the same material W
It is used for bending.

If the bottoming is determined in step S7, the process proceeds to step S19 in the flowchart of FIG. In step S19, based on the information of (2) ′, the angle of gradient change near the final stroke is determined by the comparison determination means 67. If the material is not in contact with the slope of the punch P as shown in FIG. For example, it is determined to be bottoming 1 and, if the material is in contact with the slope of the punch P and opens outward as shown in FIG.

If it is determined in step S19 that the bottoming I has occurred, the process proceeds to step S20, and the process proceeds to step S20.
At 20, n and E values are assumed. In step S21, the air bend final winding angle φ′1 is calculated by the second calculating means 65 by φ′1 = f (DA, μ, PR, T, V, DR,
n). Further, in step S22, the assumption is made of the bottoming area winding angle φ ″ 1, φn, and in step S23, the calculation of the F value based on the actual bending load P2 is performed in the second
F = f (PR, T, V, DR, DA,
n, P2, B, μ, φ ″ 1, φn, A1).

[0040] F value in step S24 is temporarily determined, in step S25 the calculation of the theoretical blade distance S _t second calculating means 6
5, _St = f (PR, T, V, DR, DA, φ ″ 1, φ
n, n, P2, B, F, μ, φ ′, A1). Further, in step S26, the calculation of the logical springback amount Δθ is performed by the second calculating means 65, and Δθ = f (E, n,
B, T, F, PR, φ ″ 1, φn, P2, DA, μ, A
1, V, DR, φ′1).

The theoretical blade distance S _t and the actual blade spacing S2 in step S27, is the theoretical amount of springback Δθ and measuring spring back amount Δθ1 are compared respectively, S _t = S
2. Return to step S22 until Δθ = Δθ1, and if S _t = S2 and Δθ = Δθ1, step S28
Then, the n value, the E value, and the F value are determined.

Accordingly, steps S20 to S
28, n value of material attribute used in bottoming I, F
Value and E value are calculated and blank W from the same material W
Used to bend _B.

If it is determined in step S19 that it is bottoming II, the flow advances to step S29 in the flowchart of FIG. In the step S29, while calculating the contact state of the punch P and the test piece W _T based on punch slope length PL, n values of material constants (material attributes) using a formula of bottoming II regions, F value, E The value is back calculated with the same idea as bottoming I.

[0044] Thus, to be bending bottoming I as well as the blank W _B also in this case in the bottoming II, n value, F value, E value is used.

[0045] to be bending the blank W _B of the same material W as the test piece W _T, air bend, bottoming I, by the processing of bottoming II, n value was determined in the above, F value, the E value, respectively By taking in the processing condition determining means 69 and determining the load (pressure) and the D value of the main cylinders 9L and 9R as the processing conditions required at the time of bending, the actual bending is performed. A product having better bending accuracy than bending can be obtained.

The obtained material constants of the specific material A, ie, Young's modulus, n-th order hardening index, and plasticity coefficient, are stored in a database, and the material constant data stored under the following new bending conditions that will be generated in the future. There are the following three cases when creating the processing data (D value, L value) that becomes a predetermined target angle using the mold information data to be used.

(1) The work angle during bending can be detected by the measurement indicator 39, and the target bending angle 9
In the case of 0 °, similarly to the above-described test piece bending, the target angle is, for example, 90 °, so that the data obtained by directly bending the test piece (springback amount 2 °, pinching angle 88 °, elongation value 0.1 mm) is used. Process.

Therefore, if the ram is stopped when the sandwiching angle detected by the measuring indicator 39 becomes 88 °, the angle after the work is taken out becomes 90 °.

Since the elongation value at the target angle of 90 ° is 0.1 mm, the position (L value) of the back gauge is a position in which the elongation value is taken into consideration with the flange length of the work.

(2) It is possible to detect the work angle during the bending by the measurement indicator 39, and the target bending angle 90
For product processing other than ° (acute angle bending, obtuse angle bending), Young's modulus, n, which is the material constant calculated by test piece bending
The work sandwiching angle is obtained by bending simulation using the power-stiffening index and the plasticity coefficient.

(3) When the measuring indicator 39 cannot be used (when the bending angle cannot be detected by the measuring indicator 39: for example, when the flange length is extremely short and laser light cannot be irradiated). (When the flange length is extremely long and the flange bends) (2) Similarly, by using the Young's modulus, the n-th hardening index, and the plastic coefficient, the bending simulation and the mechanical bending calculation formula are used. The D value at the final target angle is calculated.

Next, as the bending conditions, the material SUS, the work plate thickness 1.2 mm, the bending length 200 mm (for trial bending), the mold conditions PA = 30 °, PR = 0.65 mm, D
A = 30 °, V = 8 mm, DR = 1 m, the friction coefficient μ = 0, 0.15 of the theory of plasticity was set, the required tonnage, the amount of springback, and the stroke were measured. When the E value, f value, and n value were calculated from the formulas (two types of friction coefficients), the following results were obtained.

Condition 1: Material constant calculated by tensile test (conventional) Condition 2: Material constant calculated with μ = 0 (this case) Condition 3: Material constant calculated with μ = 0.15 (this case)

[Table 1] FIGS. 15A and 15B show, for example, the results of the springback amount SB and the required tonnage when bent under the above conditions.

As can be seen from the results, the actually measured values are far apart from the condition 1 and close to the conditions 2 and 3, and the actual values are the E, n and F values obtained under the conditions 2 and 3. It has been proved that a product having good bending accuracy can be obtained by bending the steel sheet into a shape.

The present invention is not limited to the above-described embodiments of the present invention, but can be embodied in other forms by making appropriate changes.

[0056]

As will be understood from the above description of the embodiments of the present invention, according to the first aspect of the present invention, a test piece is cut out from the same material as the blank, and the test piece cut out is tested. Bending is performed. The Young's modulus, n-th order hardening index, and plasticity coefficient can be obtained based on various data at the time of trial bending, for example, target angle information, required tonnage information, stroke information, mold information, and springback information. The obtained Young's modulus, n-th hardening index, and plasticity coefficient can be used for actual bending.

According to the second, third, and fourth aspects of the present invention, the test piece is cut from the work body or the work rod, and the test piece is subjected to test bending. Coefficients at the time of this test bending, such as target angle information, required tonnage information, stroke information, mold information, springback information, and various values detected by the position sensor, pressure sensor, bending angle detecting device, and bending angle measuring device Based on the detected value, Young's modulus, n-th power index, and plasticity coefficient are obtained as material attributes by a material attribute calculating means.

The processing conditions for blanks are determined by the processing condition determining means by using these various material attributes obtained by the material attribute calculating means in the calculation when the blank is obtained by bending the same material as the test piece. When the bending machine is controlled under the processing conditions and the work is bent, a bent product having better bending accuracy than before can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic front view of a bending apparatus according to the present invention.

FIG. 2 is an enlarged side view of a measurement indicator section in FIG.

FIG. 3 is a cross-sectional view illustrating an internal configuration of a detection head.

FIG. 4 is an explanatory diagram showing a principle of measuring a bending angle by a detection head.

FIG. 5 is a graph showing a principle of measuring a bending angle by a detection head.

FIG. 6 is a configuration block diagram of a control device.

FIGS. 7A and 7B are side views of a punch and a die, respectively.

FIG. 8 is an explanatory diagram of a work used when processing a bend.

FIG. 9 is a graph showing the relationship between the blade distance and the actual bending load when the work is bent.

FIG. 10 is a flowchart illustrating the operation of the present invention.

FIG. 11 is a flowchart illustrating the operation of the present invention.

FIG. 12 is a flowchart illustrating the operation of the present invention.

FIG. 13 is a flowchart illustrating the operation of the present invention.

FIGS. 14A to 14D are explanatory diagrams illustrating air bending or bottoming at the time of bending.

15 is an explanatory diagram for explaining the theory blade between blade distance S _t.

FIGS. 16A and 16B are diagrams showing measurement results when comparison processing is actually performed under the conditions 1, 2, and 3;

[Explanation of symbols]

 Reference Signs List 1 press brake (bending device) 9L, 9R main cylinder 17L, 17R pressure sensor 23L, 23R position sensor 27 bending angle measuring device 30 bending angle measuring device 59 memory 61 first calculating means 63 actual bending load and distance between blades Relationship File 65 Second Computing Means (Material Attribute Computing Means) 67 Comparison Judging Means 69 Machining Program Memory 71 Machining Condition Determining Means P Punch D Die

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4E063 AA01 BA07 CA01 FA05 JA07 KA07 KA10 LA03 LA08 LA10 LA11 LA17 LA19 MA30

Claims (4)

[Claims] A test piece is cut from the same material as a blank, and a Young's modulus, an n-th power index, and a plasticity coefficient are obtained based on various data at the time of test bending of the test piece. Method. 2. A test piece is cut from a work body or a work rod from which a blank is cut, a test bending is performed using the test piece, and a material attribute is determined based on various coefficients at the time of the test bending. A bending process is performed on the workpiece by controlling the bending machine by using the calculation for bending the blank. 3. The coefficients are target angle information, required tonnage information, stroke information, mold information, and springback information, and the material attributes are Young's modulus, n-th power index,
3. The bending method according to claim 2, wherein the bending coefficient is a plasticity coefficient. 4. A position sensor for detecting a relative positional relationship between a punch and a die, a pressure sensor for detecting a decrease in load, and a fold when a workpiece is bent by cooperation of a punch and a die. A bending angle detection device for detecting a bending angle,
Perform a test bending using a bending angle measuring device that measures the finished angle after bending, and a test piece cut from the work body or work rod from which the blank is cut, and based on the coefficients at the time of this test bending. Material attribute calculating means for calculating a material attribute, and processing condition determining means for determining a blank processing condition by using the material attribute obtained by the material attribute calculating means in a calculation for bending the blank. A bending apparatus characterized by comprising: