JP7521794B2 - Bending machine, bending method and program - Google Patents

Description

The present invention relates to a processing technology that performs bending forming on a plate-shaped workpiece by plastic deformation.

Traditionally, linear heating bending, linear press bending, and roll bending have been the mainstream methods for bending thick plates used in ship hull structures, etc. Linear heating bending is highly dependent on the experience of the engineer, and has issues such as not being applicable to arbitrary three-dimensional shapes. Linear press bending and roll bending require large equipment.

Meanwhile, in recent years, incremental sheet forming, a dieless forming technique for forming thin metal sheets (sheets) into any shape, has been attracting attention as a technology for high-mix, low-volume production (e.g., Non-Patent Documents 1 and 2). Incremental sheet forming is a plastic processing technique in which the tip of a small rod-shaped forming tool is brought into contact with a metal sheet and slid or rolled to continuously plastically deform the metal sheet locally into any shape.

Kimiyoshi Kitazawa, Masakatsu Nakane, "CNC incremental stretch forming of semi-ellipsoidal aluminum sheet" Light Metals Research Paper, Vol 47, No. 8, P440-P445, 1997. Nobuyuki Suzuki, Toru Jinishi, "Processing process combining incremental forming and superplastic forming - Aiming for flexible thickness arrangement of sheet metal parts -" Journal of the Japan Society for Technology of Plasticity, Vol. 54, No. 628 (May 2013)

On the other hand, for thicker plate-like plates, the incremental sheet forming method is not suitable because the tool cannot be slid, and so traditional bending methods currently rely on linear heating or continuous cold pressing along a straight line. In this case, the heating method has problems with material deterioration, and the forming process takes a long time, and it is difficult to form a three-dimensional curved surface using the method of pressing along a straight line.

The present invention has been made in consideration of the above, and provides a bending machine, bending method, and program that can perform three-dimensional bending plastic deformation of plate-shaped workpieces into any shape in a short time using simple equipment.

The bending machine according to the present invention comprises a processing tool, a drive unit that slides the processing tool above and parallel to a horizontal XY plane relative to a plate-shaped workpiece that is the subject of plastic deformation processing and is supported on the XY plane, and raises and lowers the processing tool in a Z direction perpendicular to the XY plane, and a control unit that issues instructions to the drive unit to sequentially slide the processing tool relatively to multiple target positions on the XY plane based on predesigned processing conditions, and to lower and raise the processing tool relatively in the Z direction at each target position by a displacement amount corresponding to the target position, and to move the processing tool to the lowered position in a predetermined time.

The bending method according to the present invention involves sliding a processing tool relative to a plate-shaped workpiece supported on a horizontal XY plane, which is the subject of plastic deformation processing, in sequence to a number of target positions on the XY plane, based on predesigned processing conditions for the workpiece, and lowering and raising the processing tool relative to the workpiece in the Z direction by a displacement amount corresponding to the target position at each target position, and moving the processing tool to the lowered position in a predetermined time.

The program according to the present invention causes a processor to function as a design means for designing, based on information on the shape, specifications and target shape of a plate-shaped workpiece supported on a horizontal XY plane and subject to plastic deformation processing, multiple target positions on the XY plane of the workpiece, the sliding order of the processing tool to the multiple target positions, the descent and ascent displacement amount of the processing tool in the Z direction perpendicular to the XY plane at each target position, and the movement time to the descent position, as well as a control means for instructing the processing tool to sequentially control the sliding to the multiple target positions, and to control the descent, ascent displacement and stop at each target position, based on the processing conditions designed by the design means.

According to these inventions, the processing tool is slid sequentially to multiple target positions on a horizontal XY plane relative to the workpiece, and at each target position, the processing tool is lowered and raised in the Z direction relative to the workpiece by the displacement amount corresponding to the target position, and is moved to the lowered position in a predetermined time, thereby bending the workpiece. In this way, the processing tool is pressed sequentially against multiple points on the surface of the workpiece to sequentially generate localized plastic deformation, thereby forming the target shape for the entire workpiece. Therefore, three-dimensional bending plastic deformation can be performed on a plate-shaped workpiece into any shape in a short time using simple equipment.

The present invention also includes a processing condition design means for designing the processing conditions for plastically deforming the workpiece into a target shape. With this configuration, the processing procedure is designed in advance, making it possible to operate the processing machine automatically.

In addition, by including the multiple target positions in the processing conditions, bending can be performed on the entire surface of the workpiece.

In addition, by including the order of the multiple target positions in the processing conditions, the processing process can be made more efficient.

The drive unit also includes a press unit that displaces the tool in the Z direction, and an XY slide table that slides the workpiece on the XY plane. With this configuration, the tool is raised and lowered and the workpiece is slid using separate members, which can simplify the overall configuration, for example when machining a large workpiece.

According to the present invention, it is possible to perform three-dimensional bending plastic deformation on plate-shaped workpieces into any shape in a short time using simple equipment.

1 is a schematic configuration diagram showing a first embodiment of a bending machine according to the present invention; 1A and 1B are diagrams showing members for supporting a plate-shaped workpiece, in which (A) shows a support member having an annular edge, and (B) shows a support member that supports at multiple points. FIG. 1 is an image diagram illustrating a scene of incremental plate forming. FIG. 11 is a diagram showing the relationship between the target shape of a workpiece and the design of machining conditions; (A) is an image of the target shape, and (B) is a diagram explaining a finite element model applied as an example when designing machining conditions. FIG. 13 is a diagram for explaining an example of machining positions and machining orders as machining conditions, in which (A) is associated with a work surface, and (B) is a data table thereof. FIG. 1 is a diagram showing an example of deformation forming of a work surface pressed by a tool. 11 is a flowchart showing an example of a machining condition design support process executed by a control unit. 5 is a flowchart showing an example of a processing process executed by a control unit. FIG. 13 is a diagram showing the conditions of a workpiece used in an experimental example. 1 is a table showing the machining position (X, Y coordinate values), the machining displacement (Z value), and the machining order (n) in this experimental example. 1 is a diagram comparing vertical dimension values (Z values) obtained by simulation (shown by black circles in the diagram) with deformation dimensions (Z values) obtained by experiment (shown by black triangles in the diagram).

Figure 1 shows a schematic diagram of the overall configuration of a bending machine according to the present invention. The bending machine 1 includes a control unit 10 that performs information processing and numerical control (CNC), and a processing unit 20 that performs bending processing on a workpiece 3 under computer numerical control based on information processed by the control unit 10.

The control unit 10 includes a processor unit 11 with a CPU, a memory unit 12 connected to the processor unit 11, a display unit 13 that appropriately displays input information and processing information, and an operation unit 14 consisting of, for example, a touch panel that accepts input of necessary information. The memory unit 12 includes a control program memory unit 121 that includes a design program and a numerical analysis program, which will be described later, and other programs, and a machining condition memory unit 122 that stores the designed machining conditions.

The processor unit 11 executes a control program to function as a calculation unit 110 and a machining control unit 113. The calculation unit 110 includes a machining condition design unit 111 and a numerical analysis unit 112. The machining control unit 113 includes a timer 114 that measures each processing time, a slide control unit 115, and a press control unit 116.

The processing condition design unit 111 performs processing to design processing conditions for forming the plate-shaped workpiece 3 to be bent into a target shape. The plate-shaped workpiece 3 applied to this embodiment is, for example, a metal material such as iron, stainless steel, aluminum, copper, or an alloy, and the plate thickness depends on the material and planar size, but is generally 2 mm or more thicker than sheet material, more preferably 4 mm or more, and is targeted for thick plates even thicker than that. In this embodiment, for example, the lower end of a rod-shaped processing tool 26 is pressed against (pressed against) the plate-shaped workpiece 3 to locally plastically deform the workpiece 3, and such local plastic deformation is performed sequentially at multiple points, thereby forming the workpiece into an arbitrary shape (incremental plate forming).

Figure 3 is a diagram illustrating one scene in such incremental plate forming, showing the state in which the tool 26 is lowered from above to a certain point (position) on the top surface of the workpiece 3 to press down on the workpiece and perform pressing. In Figure 3, the tool 26 is slid to the target position in the horizontal direction (X-axis, Y-axis) at a reference height above the horizontally placed workpiece 3, for example, and at the target position, it is lowered by a designed amount and pressed against the surface of the workpiece 3 (pressing is performed). The workpiece 3 is pressed downward at the target position by the tool 26, causing it to bend and undergo plastic deformation.

The deformation of the workpiece 3 is set as a target shape (three-dimensional curved surface), for example as shown in FIG. 4(A). The machining condition design unit 111 designs the machining conditions based on the specifications (various elements) of the workpiece 3 and the target shape. The specifications of the workpiece 3 include size, elastic modulus, poison ratio, and yield stress.

In this embodiment, as shown in FIG. 4B, the workpiece 3 is divided into solid elements of a predetermined small size, and the machining condition design unit 111 calculates the machining conditions based on a finite element model using such solid elements. Here, the machining conditions include the machining position (X, Y coordinate values), machining displacement (Z value), machining order (n), machining time (t), and support conditions for the workpiece 3 for the finite element model. In this embodiment, the size of the solid element is about 20 mm x 20 mm for a workpiece with an XY plane of about 1,000 mm x 1,000 mm. In addition, the support conditions for the workpiece 3 may be such that, when the flat workpiece 3 is supported at least at three points on its edge region, one support point is fixed (movement is restricted) in the X, Y, and Z directions, and the remaining support points are simply supported from below.

The machining position (X, Y coordinate values) may be set based on, for example, a specific portion of the work support portion 23 (see FIG. 1) that supports the work 3, and the machining displacement (Z value) may be set based on a height position above the work support portion 23 that exceeds at least the plate thickness of the work 3. These position information may be coordinate values or numerical values converted into a drive signal that can be numerically controlled by a computer. The machining position information may be coordinate values relative to a reference position or a relative slide amount along the machining order (n). The machining displacement (Z value) refers to the amount of descent from the position where the lower end of the tool 26 is located at the reference height in the vertical direction. The tool 26 is generally used as a rod-shaped tool that is upright, has a diameter of 100 mm, and has a lower end that is, for example, a hemispherical shape. Instead of a hemispherical shape, the lower end of the tool 26 may be a part of a sphere, or may be another curved surface or a flat surface. The processing tool 26 does not need to be rod-shaped, but may be a tool formed only of the lower end component (e.g., the hemispherical portion) described above.

The machining condition design unit 111 also performs optimal design, for example, to minimize the number of machining sequences (n). For example, in FIG. 5(A), 16 target positions (n1, n2, ..., ni) are set for a 1,000 mm x 1,000 mm workpiece 3. Furthermore, as shown by the arrows in FIG. 5(A), in order to perform efficient machining, the machining sequence (n) is designed to minimize the slide length of the tool 26 between adjacent machining positions. Alternatively, the order of the path may be such that the total slide length is the shortest. Furthermore, as shown in FIG. 5(B), the machining displacement (Z value) and machining time (t) are designed for each target position (n1, n2, ..., ni). The machining time (t) may be constant.

The external control unit 40 shown in FIG. 1 has the same functions as the control unit 10 and is provided as necessary. This external control unit 40 stores a design program in a memory unit 42, acquires information on the specifications and target shape of the workpiece 3 to be machined input via a display unit 43 and an operation unit 44, and executes the same processing as the calculation unit 110 of the control unit 10 in a calculation unit 411 of the control unit 41. The designed processing conditions can be written to the processing condition storage unit 122 of the control unit 10 via a wired or wireless connection. By adopting such an embodiment, it is possible to design and calculate the processing conditions at an appropriate time in a location physically separated from the bending machine 1.

Next, the processing unit 20 will be described. The processing unit 20 includes a mechanism for supporting the workpiece 3 and a mechanism for processing the workpiece 3. The support mechanism includes a Y-axis bed 21 and an X-axis bed 22 that are placed in two layers on the floor surface F, and a workpiece support unit 23 is mounted on the top surface of the upper X-axis bed 22. The workpiece 3 is supported on the top of the workpiece support unit 23.

On the other hand, a frame body 24 having, for example, a gate shape is installed so as to surround the Y-axis bed 21, the X-axis bed 22 and the work support part 23, and a press machine 25 is disposed near the center position in the X direction.

The Y-axis bed 21 and the X-axis bed 22 are equipped with long guide rails 212, 222 installed on the undersides of the bed bodies 211, 221 in directions perpendicular to each other, and sliders 213, 223 that can slide back and forth on the guide rails. This allows the Y-axis bed 21 to move in the Y-axis direction, and the X-axis bed 22 to move in the X-axis direction. Therefore, the work support part 23 arranged on the upper surface of the X-axis bed 22 can slide on the XY plane. The Y-axis bed 21 and the X-axis bed 22 form a so-called XY slide table.

Figure 2 shows the shape of the work support part that supports the plate-like workpiece 3 having a square shape. Figure 2(A) shows a shape that supports the entire edge of the workpiece 3, and Figure 2(B) shows a shape that supports the edge of the workpiece 3 in a point-like manner at appropriate locations.

In FIG. 2(A), the work support portion 23 is a rectangular ring-shaped body that supports the work 3 at the peripheral edge 231. An L-shaped protrusion 232 is arranged at each of the rectangular corners of the edge 231 to restrict movement. Note that, for convenience, only one corner of the rectangle is shown in FIG. 2. The corner of the work 3 fits into the protrusion 232 to restrict movement in the XY directions. Note that, although not shown in the figure, one of the rectangular protrusions 232 may have a structure in which a ceiling is provided on the upper surface of the protrusion 232 in order to also restrict movement of the work 3 in the Z direction.

2B, the work support section 230 includes a rod-shaped support protrusion 2301 arranged below the edge of the work 3, and a low-profile auxiliary protrusion 2302 as required. The support protrusions 2301 are arranged facing upward at positions corresponding to the corners of the work 3. A predetermined number of auxiliary protrusions 2302 are arranged in the middle of each side of the work 3, and abut against the bottom surface of the work 3 that bends during pressing to prevent excessive downward bending. A low-height auxiliary protrusion 2302 corresponding to the amount of bending is adopted. In FIG. 2B, one auxiliary protrusion is provided at the center position of the side. Note that one of the support protrusions 2301 is provided with a mechanism for clamping the work 3 from above and below to restrict the movement of the work 3 in the Z direction. In addition, the support protrusions 2301 and the auxiliary protrusions 2302 may be provided with a gimbal mechanism or a universal joint structure so as to always face and contact the bottom surface of the bent work 3.

Returning to FIG. 1, the numerical analysis unit 112 performs a computer simulation of bending using the processing conditions initially designed by the processing condition design unit 111. More specifically, the numerical analysis unit 112 applies the finite element method to approximately solve the behavior of plastic deformation, thereby simulating the shape of the bending of the workpiece 3. The numerical analysis unit 112 also compares the formed shape obtained by the simulation with the target shape to determine the shape accuracy. The determination is made based on, for example, the difference between the two shapes to determine whether the accuracy is good or bad. Furthermore, if the numerical analysis unit 112 determines that the accuracy is poor, it instructs the processing condition design unit 111 to redo the processing conditions.

The workpiece 3 shown in Figure 6 is an example of mild steel with dimensions of 1,000 mm x 1,000 mm, thickness of 10 mm, elastic modulus E = 2.1E5 MPa, poison ratio 0.3, and yield stress of 240 MPa. Figure 6 shows a case where a bending target shape of 200 mm is set at the center of this workpiece 3, and the displacement stops at 193 mm due to elastic springback and thickness changes. Note that the stripes in the figure indicate the Z-axis contour. Since the multi-point forming process is nonlinear, it is preferable to redesign the processing conditions until the deviation that occurs in the formed workpiece falls within the allowable deviation from the target shape.

Next, the slide control unit 115 of the processing control unit 113 moves the Y-axis bed 21 and the X-axis bed 22 in the Y-axis and X-axis directions via the drive unit 27. The bed bodies 211, 221 are connected to, for example, hydraulic servo presses 214, 224 as a movement drive source, and are slid in the X-axis and Y-axis directions upon receiving a drive signal from the XY-axis drive unit 271 of the drive unit 27. This makes it possible to align any part of the top surface of the workpiece 3 with the workpiece 3 of the press machine 25. The movement drive source may be an electric press or a servo press.

The press control unit 116 drives the press machine 25 via the Z-axis drive unit 272. The press machine 25 is one that is capable of generating a maximum pressing force taking into account the plate thickness, material, and amount of processing displacement of the workpiece 3, and the maximum pressing force may be, for example, several tons to several tens of tons.

Figure 7 is a flowchart showing an example of a processing condition design support process executed by the calculation unit 110 (or the calculation unit 411). First, a design program is started, and specification information and target shape information of the workpiece 3 are acquired (step #1). Next, a design process of the initial processing conditions is executed (step #3). The initial processing conditions are designed according to a preset method, including the support conditions of the workpiece 3, the processing position (X, Y coordinate values), the processing displacement (Z value), the processing order (n), and the processing time (t). Note that some of the initial processing conditions may be set manually, or may be set automatically when the processing time is fixed, for example. Other conditions can be designed according to various rules. For example, the number of processing positions can be designed in accordance with the size, the processing positions can be designed in accordance with the target shape, and the processing displacement can be designed according to the number of processing positions and the processing positions.

Next, a numerical analysis of the point bending is performed based on the initial processing conditions and the finite element model (step #5), and the formed shape resulting from the numerical analysis is compared with a preset target shape (step #7). Various comparison methods can be applied, and an appropriate comparison method may be adopted according to the type of target shape. As an example of a comparison method, the maximum difference or square sum of the shape at each product position, and/or the positional deviation of the curved surface in the XY direction may be applied and treated as the shape accuracy.

As a result of the comparison, it is determined whether the shape accuracy is within a predetermined threshold value (step #9), and if it is determined that the shape accuracy is low (NG), an instruction to change the processing conditions is given and the change process is performed (step #11), and the process returns to step #5, where the numerical analysis is redone. It is preferable that the change in the processing conditions is at least one of the following elements: change in the number of processing positions, change in the processing positions, change in the processing displacement, and change in the processing time. It is also more preferable that the change in the processing conditions is adjusted by adjusting the change elements and the change amount according to the comparison result between the formed shape and the target shape (according to the difference amount).

Then, in step #9, if the shape accuracy judgment is passed (OK), the processing conditions are finalized (step #13) and are transferred to and stored in the processing condition memory unit 122.

Figure 8 is a flowchart showing an example of a processing process executed by the processing control unit 113. First, the processing conditions are read from the processing condition storage unit 122 (step S1), and the value "1" is set to n, which indicates the processing order (step S3).

Next, when the slide control unit 115 sets the coordinate values xn, yn (n=1) indicating the machining position for the first machining order (step S5), the Y-axis bed 21 and the X-axis bed 22 are driven to slide toward this machining position at a preset predetermined speed (step S7). Then, it is determined whether the target position has been reached (step S9), and if it is determined that the target position has been reached, the machining displacement (value Zn) is set (step S11). Then, a descent (press) instruction is issued (step S13). When the workpiece 3 is lowered from the reference height to the machining displacement (value Zn) position at a predetermined speed upon receiving the descent instruction, the timer 114 starts timing and a predetermined machining time (tn) is timed at the lowered position (step S15), and after the time is measured, the workpiece 3 is raised to the reference height at a predetermined speed (step S17). In addition, by setting the descent speed of the workpiece 3 to a relatively low speed, the impact when it comes into contact with the workpiece 3 can be mitigated, and the occurrence of scratches, localized dents, and damage (such as cracks) not only on the tool 26 but also on the surface of the workpiece 3 can be suppressed.

Then, it is determined whether the reference height position has been reached (returned) (step S19), and if it is determined that the reference height position has been reached, it is determined whether the processing order (n) has exceeded the final order ni (step S21). If it has not been exceeded, the processing order is incremented by 1 (step S23), and the process returns to step S5, and the processing process is repeated for the next processing position. Then, if it is determined in step S21 that the processing order (n) has exceeded the final order ni, the processing process is considered to have been completed for all processing positions, and this flow is terminated.

The amount of descent or elevation of the tool 26 may be confirmed by measuring the drive signal or drive time, or the movement may be controlled by measuring the position of the tool 26 using a position sensor (e.g., an encoder or photointerrupter).

The present invention can adopt the following aspects:

(1) The relative movement between the tool 26 and the workpiece 3 in the XY plane may be performed by driving either one of them, and the relative movement between the tool 26 and the workpiece 3 in the Z direction may be performed by driving either one of them. This provides a highly flexible device that can appropriately adopt a drive method that is structurally simpler.

(2) In the above embodiment, the example size of the workpiece 3 is 1,000 mm x 1,000 mm x 10 mm, but it may be smaller in size, or conversely, it can be provided as a general-purpose type that can be applied to a larger size such as 3 m x 6 m.

(3) The processing time (t) can be set to a few seconds to a few minutes, preferably about one minute, depending on the size, thickness, and material of the workpiece. This method makes it possible to shorten the work time that took a day or more with conventional heating-type processing machines to about a few hours. In addition, the press control unit 116 stops the workpiece 3 at the lowered position for a predetermined processing time (tn), but instead, the movement time from the start of descent to the lowered position, or the movement time from the start of descent to the end of ascent, may be treated as the processing time (tn). In this case, movement control may be included such that the workpiece starts to rise immediately or after a required time from the lowered position.

<Experimental Example> The experimental example will be explained below with reference to Figures 9 to 11.

As shown in Figure 9, the workpiece 3 used in the experimental example is a square with sides of 500 mm and a thickness of 8 mm made of SS400 (steel plate). Plate-shaped support protrusions 2301 are arranged at positions corresponding to the four corners of the workpiece 3 for support purposes, and auxiliary protrusions 2302 are arranged at positions corresponding to the middle of each side, at a position -33 mm lower than the support protrusions 2301, on which the workpiece 3 is placed. The workpiece 3 is also clamped between a pressing member of the same shape as the support protrusions 2301, which is arranged on the support protrusions 2301.

Figures 10(A) and 10(B) show the machining positions (X, Y coordinate values), machining displacement (Z value), and machining order (n) in this experimental example. In this experimental example, the machining time was about 10 seconds per location. The machining positions were set so that the center of the workpiece 3 was the first (n=1), followed by eight equally sized counterclockwise directions on an equal radius, and then the machining positions were set so that the diameter increased with each revolution, with the last being the 33rd. Details of the machining conditions are shown in Figure 10(B). Figure 10(B) also shows the machining displacement (Z value) at each machining position. The workpiece 3 was formed into an approximately hemispherical shape with the deepest point at the center. The tool 26 was a cylinder with a diameter of 60 mm, and the tip was spherical with a curvature of 100 mm.

Figure 11 is a diagram comparing the vertical dimension values (Z values) obtained in the simulation (shown as black circles in the figure) with the deformation dimensions (Z values) obtained from the experiment (shown as black triangles in the figure). Figure 11(A) shows the Z values in the A-A' direction, and Figure 11(B) shows the Z values in the B-B' direction. As shown in Figures 11(A) and (B), it was found that both Z values were determined and approximated, and that the target shape and the formed shape were approximately the same. Therefore, it was confirmed that this bending method can achieve bending as designed.

REFERENCE SIGNS LIST 1 bending machine 10 control unit 11 processor unit 110 calculation unit (design means)
111 Machining condition design unit 112 Numerical analysis unit 113 Machining control unit (control means)
115 Slide control unit 116 Press control unit 121 Control program storage unit 20 Processing unit 21 Y-axis bed (XY slide table)
22 X-axis bed (XY slide table)
214, 224 Hydraulic servo press (drive unit)
23 Work support section 25 Press machine (drive section)
26 Tools (machining tools)
27 Drive unit 3 Work

Claims (5)

Machining tools and
a drive unit that slides the processing tool above the XY plane and in parallel with the XY plane relative to a plate-shaped workpiece that is a target of bending plastic deformation processing and is supported on a horizontal XY plane, and raises and lowers the processing tool in a Z direction perpendicular to the XY plane;
a control unit that issues to the drive unit an instruction to relatively slide the processing tool to a plurality of processing positions on the XY plane in order based on predesigned processing conditions, and an instruction to relatively lower and raise the processing tool in the Z direction at each processing position by a displacement amount corresponding to the respective processing position, and to move the processing tool to a lowered position in a predetermined time ,
A bending machine in which the processing conditions are calculated based on a finite element model using solid elements in which the workpiece is divided into predetermined small sizes . The bending machine according to claim 1, which is equipped with a processing condition design means for designing the processing conditions for plastically deforming the workpiece into a target shape. 3. The bending machine according to claim 1, wherein the drive unit includes a press unit that displaces the tool in the Z direction, and an XY slide table that slides the workpiece in an XY plane. Based on predesigned processing conditions for a plate-shaped workpiece supported on a horizontal XY plane and to be subjected to bending plastic deformation processing, a processing tool is slid relative to the workpiece to a plurality of processing positions on the XY plane in order, and at each processing position, the processing tool is lowered and raised relatively in a Z direction perpendicular to the XY plane by a displacement amount corresponding to the processing position, and moved to the lowered position in a predetermined time;
A bending method in which the processing conditions are calculated based on a finite element model using solid elements in which the workpiece is divided into predetermined small sizes. a design means for designing, as processing conditions, a plurality of processing positions on the XY plane of the workpiece, a sliding order of the processing tool to the plurality of processing positions, a descent and ascent displacement amount of the processing tool in a Z direction perpendicular to the XY plane at each processing position, and a movement time to the descent position, based on information on the shape, specifications, and processing target shape of a plate-shaped workpiece supported on a horizontal XY plane and which is the target of bending plastic deformation processing; and a control means for instructing the processing tool to sequentially perform slide control to the plurality of processing positions, and the descent, ascent displacement control, and stop control at each processing position, based on the processing conditions designed by the design means;
A program in which the machining conditions are calculated based on a finite element model using solid elements in which the workpiece is divided into predetermined small sizes.

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