JP3437413B2 - Bending simulation method and apparatus - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bending process for automatically obtaining an optimum stroke amount of a tool for obtaining a target folding angle by simulation without performing a trial bending by a bending machine before performing a bending process. The present invention relates to a simulation stroke amount updating method and apparatus.

[0002]

2. Description of the Related Art FIG. 6 is a schematic configuration diagram of a line control system for a folding machine. The line control system of the folding machine shown in FIG. 6 includes the central station 1, the CAE device 2, the automatic programming device 3, and the NC device 5 for controlling the folding machine 4 in the LA.
It is connected to N.

Generally, in bending, springback occurs during unloading. Therefore, in the line control system of the folding machine shown in FIG. 6, when the operator specifies the bending extension amount at the bending portion with the automatic programming device 3,
A work condition, a mold condition, a target Di value which is a stroke amount of a tool, etc. (hereinafter collectively referred to as a bending condition) shown in FIG. 7 are input to a CAE device, and a plate material forming simulation considering springback is performed. .

As shown in FIG. 7, the above-mentioned work conditions consist of plate thickness, Young's modulus, Poisson's ratio, yield strength, work hardening index and the like.

In this simulation screen, when the cross-sectional image of the work after springback reaches the target folding angle (hereinafter referred to as the target angle), the operator uses the image to obtain information such as the target D value, bending extension amount, and machining load. To file.

In the simulation calculation used in the CAE apparatus 2, generally, the elasto-plastic finite element method (hereinafter simply referred to as the finite element method) that can handle elastic recovery during unloading can be used to determine the deformed shape of the work after springback. Things are used.

In the method using the finite element method, the operator inputs the cross-sectional shape of the tool and the cross-sectional shape of the work based on the work condition and the mold condition shown in FIG. It gives the necessary conditions for the calculation of the law.

Then, calculation is performed to machine the tool up to the target Di value, then the cross-sectional shape of the tool is removed, necessary conditions for spring back are given, and calculation is performed until the spring back is completed.

Then, when the shape of the work after the springback is not the target angle, the operator corrects and inputs the initial target Di value, and causes the above-mentioned processing to be performed again.

[0010]

However, in the bending simulation using the conventional finite element method, when the variation angle of the work after the springback does not reach the target angle, the operator again performs the initial operation. Goal Di
Since the value has to be calculated and re-entered, there is a problem that the number of man-hours required for the operator increases.

The initial target Di value must be set in consideration of the occurrence of springback. Therefore, in order to newly set the initial target Di value, a new target Di value can be easily set only by an operator who is skilled in V-bending and has advanced working know-how. there were.

Further, in the V-bending, there is a problem in that it may not be possible to actually bend the target angle depending on each condition.

The present invention has been made in order to solve the above problems, and at the time of bending simulation, the initial stroke amount of the tool is automatically calculated to update the stroke amount of the bending simulation, and An object of the present invention is to obtain a simulation method and an apparatus for the same, which does not waste time.

[0014]

A method for simulating bending according to the present invention comprises a step of inputting and setting a work condition of a product to be subjected to the bending work, a mold condition, and a target folding angle of the work. An image of the tool is displayed according to the step of inputting a target stroke amount of an initial value of the tool for obtaining the target folding angle from each of the conditions and setting the target stroke amount of the initial value, and the setting of the target stroke amount. A step of deforming the work image by an elasto-plastic finite element method according to each condition while descending, and when the image of the tool reaches the target stroke, the image of the tool is disengaged, and the spring-backed Obtaining and displaying the work deformation image, sequentially storing the deformation angle of the work image while lowering the image of the tool, and Each time the angle is stored, a step of comparing the previous deformation angle with the current deformation angle to determine whether the current deformation angle is a backward return, and a step of displaying an error when the backward return is determined. The point is to have prepared.

The bending simulation apparatus of the present invention is a cross-sectional image of the workpiece, a connected bending simulation apparatus via a local area network to C AD device storing a cross-sectional image and the sectional image of the die of the tool A means for inputting and setting the work condition of the product to be bent, the mold condition and the target folding angle of the work, and the target of the initial value of the tool for obtaining the target folding angle from the respective conditions. A means for inputting a stroke amount and setting a target stroke amount of the initial value, and according to the setting of the target stroke amount, while lowering the image of the tool, the work image is displayed by an elasto-plastic finite element method according to each condition. Deformation means and when the image of the tool reaches the target stroke, disengage the image of the tool, and after springback Means for displaying the work deformation image and displaying the work deformation image, means for sequentially storing the deformation angle of the work image while lowering the image of the tool, and each time the deformation angle is stored, the previous deformation angle and the current deformation angle are stored. The gist of the present invention is to include means for comparing the deformation angle of No. 1 to determine whether or not the current deformation angle is a backward return, and means for performing an error display when it is determined to be the backward return.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic configuration diagram of a bending simulation device according to the present embodiment. The simulation device 20 of FIG. 1 is a function incorporated in the automatic programming device.

The simulation apparatus 20 automatically obtains a target D value based on bending information Ji consisting of a work condition Wi, a mold condition ki, a target angle θi, etc. inputted by an operator, and then a sectional image of the work is obtained. 11, the die cross-sectional image 12 and the tool cross-sectional image 13 are displayed on the display unit 21. Then, the variation image 14 of the work obtained by using the finite element method is displayed while sequentially lowering the cross-sectional image 13 of the tool until the target D value is reached.

Then, the angle θp of the variation image 15 of the work after the springback occurs when the tool cross-section image 13 is disengaged when the target D value is reached (also referred to as after unloading) matches the target angle θi. It is determined whether or not both angles do not match, a new target D value is automatically calculated, and the new target D value is updated.

When both angles match, the D value at the target angle at this time is calculated. The calculation of the D value at this target angle will be described later.

As shown in FIG. 1, the simulation device 20 includes a target stroke amount calculation unit 21, a bending information setting unit 23, a bending simulation unit 24, and a D
A value determination unit 25, a load determination unit 26, and a D value correction unit 27 are provided.

The target stroke amount calculation unit 21 is, for example,
As shown in FIG. 2, the deformed plate is assumed to have inner R = punch tip R, and a D value of a target angle (also referred to as a target stroke amount).
Is output to the bending information setting unit 23. That is, it is geometrically determined from the input conditions.

When it is notified that the target angle has not been reached, each condition is input again and a new target D value is obtained.

The bending information setting unit 23 sets the bending information Ji input by the operator in a predetermined format in the bending processing simulation unit 24.

The bending simulation processing section 24 is
Section image 1 of the tool based on the bending information Ji and the target D value
Muting the image of the work while lowering 3. Then, when the set target D value is reached, the sectional image of the tool is disengaged, and the variant image 15 of the work after springback is obtained and displayed.

Further, the variation angle θp after springback
And the target angle θi match, and if they do not match, the target stroke amount calculation unit 21 is notified that both angles do not match.

The D value determination unit 25 sequentially reads the θi values when the bending processing simulation unit 24 descends the tool based on the target D value, and compares the θi value with the previous θi. It is judged whether or not it has returned.

The load determining unit 26 stores the maximum load when the load is lowered to the target D value as the initial load, and when the load is sufficiently larger than the initial load, it determines that the load has advanced too much. The D value correction unit 27 outputs the D value corresponding to the load when the load determination unit 27 determines that the load has advanced too much, to the target stroke amount calculation unit 21, and sends an interruption signal to the work bending simulation unit 24. <Description of Operation> The operation of the bending simulation apparatus configured as described above will be described with reference to the flowchart of FIG. First, initial setting is performed (S1). The process of the initial setting S1 will be described. The operator uses the work condition Wi shown in FIG.
Bending information Ji including the mold condition ki and the target angle θi is input. The bending information setting unit 23 uses the bending information Ji.
Is set in the work bending simulation processing unit 24.

Next, the target stroke amount calculation unit 21 obtains the own stroke amount (D value) from these conditions (S).
2).

Next, the bending simulation processing section 2
In step 4, the work sectional image 11 is divided into elements (mesh division) as shown in FIG. 1 (S3).

Then, the work piece deformation process is simulated by the finite element method while lowering the cross-section image 13 of the tool (S4), and the angle θm of the work piece cross-sectional image 11 at this time is obtained (S5).

Next, the springback process is simulated by the finite element method (S6), and the displacement angle θp of the displacement image 15 of the workpiece after springback is determined (S7).

Next, it is determined whether the variation angle θp and the target angle θi match (S8).

When it is determined in step S8 that the angle θp of the work after the springback has not reached 90 degrees, the target stroke amount calculation unit 21 is activated again.

On the other hand, during the above-mentioned processing, the D-value determining section 25, the load determining section 26 and the D-value correcting section 27 are performing the processing described below.

The D value determination unit 25 sequentially reads and stores the θi value when the bending simulation unit 24 descends the tool based on the target D value. Then, it is determined whether or not this θi value is reversed from the previous θi.

For example, as shown in FIG. 5A, a coordinate system composed of an angle axis and a D value axis is provided, and the angle and Di calculated by the work bending simulation processing section 24 are set in this coordinate system.
The values and are plotted to determine if the angles revert. If it is determined that the determination result has returned, an error is displayed and the process ends.

Further, the load judging section 26 stores the maximum load when it is lowered to the target D value as the initial load while it is judged that the angle has not returned, and is sufficiently larger than this initial load. When the load is reached, it is judged to be too advanced.

For example, as shown in FIG. 5B, the load and the Di value obtained by the work bending simulation processing section 24 are plotted on the coordinate system having the load axis and the Di value, and the load is 2 When it becomes about twice, it is judged that the target D value has advanced too much. The D value determination unit 25 operates only during the first simulation, and the load determination unit 26 operates only during the second and subsequent simulations (during convergence).

That is, the D value determining section 25 and the load determining section 25 prevent the convergence calculation in the work bending simulation processing section 24 from being unnecessarily continued to be calculated.

Further, the D value correction section 27 is composed of the load determination section 2
D corresponding to the load when it is judged to be too advanced in 7
The value is output to the target stroke amount calculation unit 21, and the simulation is stopped. In FIG. 5B, A is the D value corrected.

[0041]

As described above, according to the present invention, it is possible to prevent the convergence calculation from being unnecessarily continued because the excessive advance due to the angle is determined and notified.

[0042]

[0043]

Further, depending on each condition, the convergence calculation takes a waste of time, but since the calculation is interrupted when the load is sufficiently large, an effect that the calculation time is short is obtained.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of the present embodiment.

FIG. 2 is an explanatory diagram illustrating calculation of a D value according to the present embodiment.

FIG. 3 is a flowchart illustrating an operation according to the exemplary embodiment of the present invention.

FIG. 4 is an explanatory diagram illustrating input conditions according to the embodiment of this invention.

FIG. 5 is an explanatory diagram for explaining the reversal of the angle and the determination of the load.

FIG. 6 is a schematic configuration diagram of a conventional bending line control system.

FIG. 7 is an explanatory diagram illustrating a conventional input condition.

[Explanation of symbols]

1 central station 2 CAE equipment 3 Automatic programming device 4 folding machine 5 NC device 21 Target stroke amount calculator 23 Bending information setting section 24 Bending processing simulation section

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B21D 5/02 G05B 19/4068

Claims (4)

(57) [Claims] 1. A step of inputting and setting a work condition, a mold condition, and a target fold angle of a work of a product to be subjected to input bending, and a tool for obtaining the target fold angle from the respective conditions. A step of inputting a target stroke amount of an initial value and setting the target stroke amount of the initial value, and an elasto-plastic finite element method according to each condition while lowering the image of the tool according to the setting of the target stroke amount. A step of deforming the work image, and when the image of the tool reaches the target stroke,
A step of separating the image of the tool and obtaining and displaying the work deformation image after springback; a step of sequentially storing a deformation angle of the work image while lowering the image of the tool; and the deformation angle Each time the memorized is stored, it has a step of comparing the previous deformation angle with the current deformation angle to determine whether the current deformation angle is a backward return, and a step of displaying an error when the backward return is determined. A bending method simulation method characterized by the above. 2. The maximum load when the tool is lowered to the target stroke amount is used as an initial load while the reverse return is not determined , and when the load is larger than the initial load, it is determined to be too advanced. simulation method of bending processing according to claim 1, wherein the a step. 3. A workpiece cross-sectional image, a connected bending simulation apparatus via a local area network to C AD device storing a cross-sectional image and the sectional image of the die of the tool, a bending input A means for inputting and setting the work condition of the product to be performed, the mold condition and the target folding angle of the work, and inputting the target stroke amount of the initial value of the tool for obtaining the target folding angle from each of the conditions, Means for setting an initial value target stroke amount, means for deforming the work image by an elasto-plastic finite element method according to each condition while lowering the image of the tool according to the setting of the target stroke amount, and the tool When the image of reaches the target stroke,
Means for disengaging the image of the tool, obtaining and displaying the work deformation image after springback, means for sequentially storing the deformation angle of the work image while lowering the image of the tool, and the deformation angle Each time memorizing, it has a means for comparing the previous deformation angle with the current deformation angle to determine whether the current deformation angle is a backward return, and a means for displaying an error when the backward return is determined. A bending device for simulating bending. 4. The maximum load when the tool is lowered to the target stroke amount is set as an initial load while the reverse return is not determined , and when the load is larger than the initial load, it is determined to be too advanced. The bending simulation apparatus according to claim 3, further comprising: