JP3646106B2 - Bending trajectory controlled plate bending machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for controlling the bending trajectory movement of a blade, a method for automatically correcting the bending trajectory, and the method for clamping the plate material between a lower die and a presser die and bending with a blade attached to a bend beam. The present invention relates to a plate bending machine.
[0002]
[Prior art]
Conventionally, for example, as shown in FIG. 9, the plate material 1 is bent by the blade 4 attached to the end of the bend beam in cooperation with the operation of clamping the plate material 1 between the lower die 3 and the presser die 2. The machine is widely adopted.
In this case, when the processing point K at which the blade edge 41 abuts and presses the side surface of the plate material operates from the approach position (a0) to the bending completion position (b0), the plate material may be extended. Misalignment occurs due to rubbing.
Therefore, generally, a protective sheet such as vinyl is attached to the surface of the plate material to prevent the occurrence of ironing scratches such as rubbing scratches.
However, if this ironing width is increased, the vinyl protective sheet will be torn and the surface of the plate material will be scratched, or the coated steel sheet will be damaged in painted steel sheets, which is one of the causes of product quality degradation. It was.
[0003]
Further, in the ironing bending process of the plate material as described above, a springback occurs after the plate material is bent.
Conventionally, in order to correct this amount of springback, an angle correction value for the target bending angle has been input to the bending machine, but the value has to be relied on the operator's experience and intuition.
In addition, because of large errors in bending quality such as the amount of spring back due to variations in plate thickness and rolling direction, it is necessary to repeat trial bending, resulting in defective processing and an increase in work man-hours. It was one of the major causes of material loss.
[0004]
[Problems to be solved by the invention]
In view of the technical problems inherent in the above-described conventional technology, the present invention provides a processing in which the position of the plate material pressed by the blade edge of the bending die as the processing point is the same position from the approach position to the bending completion position. It is an object of the present invention to provide a plate bending machine capable of automatically correcting various correction values such as a springback amount for a bending method trajectory of a point and a desired bending quality of the plate.
[0005]
[Means for Solving the Problems]
The technical gist of the present invention is that a plate material is clamped between a lower die and a holding die, and is bent by a blade attached to a bend beam. From a bending fulcrum along a bending side of the plate material, Based on the data obtained in advance of the relationship between the bending angle and the length L to the machining point where the blade edge comes into contact, the bending movement trajectory of the blade edge is controlled. The position of the contacting plate material is the same.
[0006]
In this case, the length L from the bending fulcrum along the bending side surface of the plate material to the processing point where the blade edge comes into contact is broken down into the bending R portion length LR and the straight portion length LS, and the bending R portion length LR It is preferable to control the bending motion trajectory of the blade edge based on data obtained by using the elongation coefficient k of the plate.
As described above, when the length L from the bending fulcrum along the bending side surface of the plate material to the processing point where the blade edge comes into contact is broken down into the bending R portion length LR and the straight portion length LS, the portion of the straight portion length LS does not stretch. Since it hardly occurs, only the change in the bending R portion length LR needs to be converted into data, and the relationship between the bending angle and the material elongation coefficient k can be derived by a simple calculation formula.
This is the same for both forward bending as shown in FIG. 1 and reverse bending as shown in FIG.
[0007]
As described above, creates a bending motion locus of the blade edge, as shown in FIG. 4 in the case of controlling, to a position of the order theta _s to correct the amount of spring back Δθ relative position theta _t bend an object It is necessary to control the bending trajectory.
The invention according to claim 2 makes it possible to automatically correct various correction values such as a springback amount Δθ for the final target quality.
Specifically, in a plate material bending machine that clamps a plate material between a lower die and a presser die and bends it with a blade attached to a bend beam, the workpiece is provided with data storage means related to the workpiece (plate material). Based on the data from the data storage means and the machining data input by the machining data input means necessary for the bending process, it is provided with means for creating a bending motion trajectory of the blade edge, and the bending motion trajectory created thereby based on the bending of the work is performed, bending with the quality data measuring means relating workpiece after machining, as well as the acceptance judgment of the work based on the quality data, by feeding back to the work data storage means, the blade It automatically corrects the bending motion trajectory of the cutting edge .
[0008]
Here, since the springback amount Δθ varies depending on the material of the plate material, the plate thickness, the bending length, and the like, the workpiece data storage means for the workpiece that has been bent so far is provided, so that the next bending is performed. When processing data such as plate material, bending length, and bending width are input, correction values such as the amount of springback are output from the work data storage means, a bending motion trajectory is created, and bending is performed based on this. Is done.
When the bending process is completed, the springback amount is measured by measuring the locus of the machining point K, and thereby it is determined whether or not the correction range is aimed, and if it is within the acceptable range, the value is stored in the work data storage means. The correction function data is additionally corrected and the correction function data is additionally corrected, whereby the learning function works and the accuracy of bending quality is improved.
In addition, if the bending quality is in a rejected range, it is immediately reflected in the bending motion trajectory creating means.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
With reference to FIG. 6, a method of bending the plate material 1 will be described.
The plate material 1 is clamped between the lower die 3 and the presser die 2, and the plate material is pressed forward from the lower approach position by the blade 41 of the bending die 4 attached to the tip of the bend beam 5. To do.
In addition, by providing the blade 42 below the bending mold, reverse bending can be performed by pressing the plate material downward from above.
In this case, the blade cutting edge 41 has a vertical rotation in which the end of the bend beam 5 provided in a substantially horizontal direction is rotated by the A axis having an eccentric shaft, and the bend beam is connected to the lower part of the arm of the bend beam via the connecting shaft 7. The position is controlled by the rotation of the D axis that is an eccentric shaft provided at the end of the arm 6.
[0010]
FIG. 3 schematically shows the relationship between the movement of the blade edge 41 and the bending angle of the plate 1 assuming that there is no springback.
In the case of forward bending of the plate material, the blade edge comes into contact with the plate material as a processing point K (a) at the approach position from the lower side in the state (a) of the clamped plate material.
Reference numeral 41a shown in FIG. 3 denotes a circumscribed circle having a blade edge shape.
When it is pushed and bent to the state of (b), the contact point (working point) of the blade edge rotates and moves along the circumscribed circle by the bending angle db, so that it does not rub.
[0011]
However, since the processing point K on the plate material undergoes elongation deformation from the bending fulcrum R ₀ (bending deformation start point) to the boundary point R (bending deformation end point) between the bending portion and the straight portion, this elongation deformation. If the machining point trajectory is not corrected by this amount, a deviation occurs so that the contact point between the plate material and the blade edge is rubbed.
[0012]
Therefore, since the contact point (processing point) between the plate material and the blade edge does not shift up and down along the surface of the plate material, the blade edge contacts the approach position of the plate material, and the position of the plate material remains the same until the bending is completed. The calculation formula to obtain the locus of the machining point was investigated.
In FIG. 3, it is assumed that the plate material changes from the state (a) to the state (c) bent at a right angle.
Let the horizontal coordinate axis be the X axis and the vertical coordinate axis be the Y axis.
The bending center (virtual point) is O, the processing point K, the bending fulcrum (starting point) is R _0, and the bending deformation end point of the plate material is R.
The height at the completion of bending at a right angle is VH, and the distance in the X-axis direction from the bending center O to the machining point K is OR.
When defined in this way, the length L = R ₀ K from the bending fulcrum (bending start point) along the bending side surface of the plate material to the processing point, the bending R portion length LR = R ₀ R, and the straight portion length LS = RK Become.
When bent at a right angle bending deformation portion and the straight portion of the boundary (bending deformation termination unit) When R _90, as the point when no assumed elongation deformation point of the R _90, when expanded to the state of (a) For easy understanding, R ₀ K = VH−OR + R ₀ R ₉₀ = VH−OR + (2 × OR × π × 1/4) when assuming no elongation deformation.
Accordingly, the straight portion length RK is as shown in FIG.
RK = (VH−OR) + (2ORπ × 1/4) − [2ORπ × (180−θ) / 360)].
Here, θ is an upper side angle formed by a perpendicular and OR as shown in FIG.
Therefore, the bending R portion LR obtained by subtracting the straight portion length LS = RK from L = R ₀ K can be derived by the following calculation formula.
The elongation coefficient with respect to the bending angle of the plate is k, the coordinates of the point R are (X _t1 , Y _t1 ), the coordinates of the point O are (X _t0 , Y _t0 ), and the coordinates of the machining point are (X _t , Y _t ) To do.
When defined in this way, as shown in FIG.
Since X _t1 = −OR × Sin (θ) + X _t0 and Y _t1 = OR × COS (θ) + Y _t0 , LR = R ₀ R = f (k) × f (X _t1 , Y _t1 ) It can be obtained by a calculation formula.
If K = f (X _t , Y _t ),
X _t = −RK × COS (180−θ) + X _t1 ,
_Yt = RK × Sin (180−θ) + _Yt1 .
The above calculation formula is an example, and can be applied and developed using a calculation formula that can predict the elongation length or a coefficient correction formula according to various bending shapes and bending angles.
Further, the present invention can be similarly applied to reverse bending as shown in FIG.
[0013]
Here, the bending R radius OR and the elongation deformation coefficient k are eigenvalues determined by the material and thickness of the plate material, and can be obtained relatively easily by experiments.
[0014]
While there have been described without considering the correction value, such as the spring back amount, in fact, as shown in FIG. 4, in order to correct the amount of spring back [Delta] [theta], to create a bending motion track to bend the angle theta _s By executing the bending process, the target bending angle θ _t is obtained.
FIG. 8 shows a flowchart for automatically correcting the correction value Δθ such as the springback amount based on the previous bending data.
When processing data such as a desired bending angle is input in advance and a bending start command is issued, the plate thickness and bending length are measured by the measuring means provided in the bending machine.
Based on these data, the previous work data stored in the data storage file provided in the personal computer is output, and a bending motion trajectory is created.
Based on this, bending is performed.
At the time of bending, since the locus of the processing point K of the blade is controlled, the bending angle and the spring back amount after the bending processing are measured.
As a result, if the correction value for the spring back amount is within the acceptable range for the bending quality of the workpiece, the value is registered as a new spring back amount or the like, and is fed back to the work data storage file for correction.
Thereby, a learning function is generated in the work data storage file, and the bending accuracy is improved.
If the deviation of the bending angle is outside the target range (acceptable range), feedback correction is made to the bending operation locus.
The bending process and the automatic correction of the correction value are completed by the above flow.
[0015]
Next, in order to actually obtain the bending motion trajectory, it is possible to obtain the coordinate transition of the processing point K (X _t , Y _t ) by changing the bending angle θ into several kinds as necessary.
As shown in FIG. 5, the coordinates of the machining point K obtained so that the position of the machining point in contact with the plate material is always the same as the position at the time of approach is K (X _t , Y _t ), and there is an A axis. If the coordinates of the position rotated to the angle θa are RA (X _a , Y _a ), and the coordinates of the position rotated the D axis to a certain angle θd are RD (X _d , Y _d ), the previously obtained K ( The values of RA (X _a , Y _a ) and (X _d , Y _d ) are easily back-calculated from the position of X _t , Y _t ).
[0016]
FIG. 7 shows a configuration block diagram of a plate bending machine using the bending motion trajectory control method described so far.
When conditions such as the material and thickness of the plate material are input to the personal computer PC using an input device such as a keyboard, a calculation formula for obtaining the locus of the machining point K under these conditions is stored in the memory in advance. The value calculated in is output to the sequencer PLC and the bending locus control device (machining point positioning complement).
Based on the output value, the A axis control device and the D axis control device determine the rotation angles of the A axis and the D axis, respectively, and the mechanical bending is performed by the operation of the servo motors of the A axis and the D axis. It is transmitted to the mechanism, and the movement path of the bending die (blade edge) is controlled.
[0017]
【The invention's effect】
In the present invention, the length from the bending fulcrum (bending start point) along the bending side surface of the plate material to the processing point where the blade edge hits is decomposed into the bending R portion and the straight portion, and the position on the coordinates is calculated. By deriving the formula, it becomes easy to complement the processing point by elongation deformation at the time of bending the plate material.
Also, by performing servo motor positioning conversion converted to the A-axis and D-axis angles based on the coordinate points extracted by this complementation, it becomes possible to suppress the displacement of the processing point on the plate material, and the occurrence of ironing scratches Can be prevented.
Also in this case, the coefficient can be easily adjusted according to the characteristics (rigidity and elongation) of the plate material by disassembling the bent R portion and the straight portion.
[0018]
In the present invention, since the operation locus (operation path) of the bending die (blade edge) can be grasped in advance, the interference check between this bending die and another die or workpiece can be performed in advance.
In addition, by determining the point and changing the speed from the start to the end of the bending operation, optimum operating conditions can be obtained taking into account the torque of the servo motor, the load on the mechanical structure, the limit value, etc. .
[0019]
Furthermore, the correction function data such as the amount of springback is stored and registered in the work data storage file of the personal computer, the operation locus of the machining point is created based on this data, and the correction value is checked after execution. Occurs and the bending accuracy is improved.
Moreover, since the number of trial bending of the workpiece can be reduced, not only the man-hours but also scrap materials can be reduced.
In particular, an expensive plate such as stainless steel has a large variation in thickness when trying to shift to an inexpensive material as much as possible. Conventionally, stable machining accuracy could not be obtained, but in the present invention, However, stable bending can be achieved, which can contribute to product cost reduction including reduction of scrap material.
[Brief description of the drawings]
FIG. 1 shows a structure of a calculation formula for obtaining a processing point of a plate material in normal bending.
FIG. 2 shows a structure of a calculation formula for obtaining a processing point of a plate material in reverse bending.
FIG. 3 is a schematic diagram showing transition of a processing point during bending.
FIG. 4 is a schematic diagram of a springback amount during bending.
FIG. 5 is a configuration diagram for determining an operation trajectory of a bending mold.
FIG. 6 is a structural diagram of a bend beam position control machine.
FIG. 7 shows a configuration example of a main part of a bending locus control mechanism in a plate material bending machine.
FIG. 8 shows an automatic correction flowchart of a bending correction value.
FIG. 9 shows an example of a method for bending a plate material.
[Explanation of symbols]
1 Plate material (work)
2 Presser mold 3 Lower mold 4 Bending mold 41 Forward bending blade edge 42 Reverse bending blade edge 5 Bend beam 6 Vertical arm 7 Connecting axis A Eccentric A axis D Eccentric D axis

Claims (2)

In a plate bending machine that clamps a plate material between a lower die and a presser and bends it with a blade attached to a bend beam, the processing point where the blade edge comes into contact with the bending fulcrum along the bending side of the plate material Data obtained by decomposing the length (L) up to the bending R portion length (LR) and the straight portion length (LS) and determining the change in the bending R portion length (LR) using the elongation coefficient (k) of the plate material. Based on the above , the bending operation trajectory of the blade blade edge is controlled, and the plate material bending machine in which the blade edge abuts on the same position from the approach position to the completion of the bending work. In a plate bending machine for clamping a plate material between a lower die and a presser die and bending it with a blade attached to a bend beam, the plate material bending means is provided with data storage means relating to a workpiece (plate material). Based on the data and the processing data input by the processing data input means required for bending processing, a means for creating a bending motion trajectory of the blade edge is provided. Bending operation is provided, quality data measuring means for the workpiece after bending is processed, the pass / fail judgment of the workpiece is made based on the quality data, and by feeding back to the work data storage means, the bending motion trajectory of the blade edge 2. The plate material bending machine according to claim 1, wherein automatic correction is performed.

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