JP2004098128A - Bending method for punch press and die for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To permit continuation of working without allowing projecting parts to be caught by a turret and a table even if a product is provided with these projecting parts when the product is downwardly bent. <P>SOLUTION: (1) The product S is formed with a half blanked coupling J by half blanking the coupling j which couples the product S to a work W and (2) thereafter the product S portion on the side opposite to the half blanked coupling J with respect to a bending line m is downwardly bent by stroking while the product S is upwardly bent around the half blanked coupling J. Also, the product S provided with a downward forming section T is upwardly bent around the half blanked coupling j. The bending punch and die P and D have a punch tip 20 for bending and a die tip 21 for bending. Both the tips 20 and 21 are freely movable in a vertical direction. The respective tips 20 and 21 are attached to the positions displaced in a direction orthogonal with the vertical direction and their respective edges 20A and 21A face each other in the vertical direction. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a bending method and a mold for a punch press that can continue processing without being caught on a turret or a table even when a projection is provided on the product, such as when the product is bent downward. About.
[0002]
[Prior art]
Conventionally, a turret punch press has, as is well known, a punch P (FIG. 11 (A)) and a die D arranged on an upper turret and a lower turret. Position.
[0003]
When the punch P (FIG. 11B) is lowered in this state, the ejector 70 on the die D side on which one end of the work W is placed sinks, so that the work W is bent downward, for example.
[0004]
After the processing, the punch P rises (FIG. 11C), and the ejector 70 also returns to the original position, and the work W is bent downward from the pass line PL as shown in FIG. The part 71 will be formed.
[0005]
[Problems to be solved by the invention]
[0006]
However, the height H between the lower turret 72 (FIG. 12) and the upper surface of the die D is extremely small (for example, about 3 mm).
[0007]
Therefore, as described above (FIG. 11), when the downwardly bent workpiece W is to be moved (FIG. 12), the downwardly bent portion 71 of the workpiece W is moved to the lower turret 72 or the table (not shown). ).
[0008]
As a result, defective products are produced, and subsequent processing cannot be continued.
[0009]
An object of the present invention is to enable processing to be continued without being caught on a turret or a table even when a projection is provided on the product, such as when the product is bent downward.
[0010]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, according to the present invention, as a first invention (FIGS. 2 and 3),
(1) A half-opening connection J is formed by half-opening a connection j connecting the product S to the workpiece W;
(2) After that, while bending the product S upward with the half-opening connection portion J as a fulcrum, the punch is characterized in that the product portion on the side opposite to the half-opening connection portion J with respect to the bending line m is bent downward by ironing. The bending method in the press,
As a second invention (FIGS. 4 and 5),
A bending method in a punch press, characterized in that a product S provided with a downwardly formed portion T is bent upward with a half punched connection portion J as a fulcrum,
As a third invention (FIGS. 6 to 10),
It has a bending punch chip 20 and a bending die chip 21. Both chips 20, 21 are movable in the vertical direction, and each chip 20, 21 is mounted at a position displaced in a direction perpendicular to the vertical direction. The bending dies are provided in a punch press, wherein the respective cutting edges 20A and 21A face each other in the vertical direction.
[0011]
Therefore, according to the configuration of the present invention, for example, using a turret punch press (FIG. 1), the work W is microjointed to form a connection portion j that connects the product S to the work W (for example, FIG. 2). Step 101, FIG. 3 (A)), if this connecting portion j is half-cut to form a half-cut connecting portion J (for example, step 102 in FIG. 2, FIG. 3 (B)), a cut-and-raised bending die is used. According to P and D (FIG. 6), while bending the product S upward with the half-opened connection portion J as a fulcrum C, the product S portion on the opposite side of the half-opened connection portion J with respect to the bending line m is ironed downward. (Steps 103 to 104 in FIG. 2 and FIGS. 3C to 3D), so that the projection S such as the flange F bent downward with respect to the product S (FIG. 3D) can be used. Is provided, since the product S is bent upward, Even when the product S is carried out, the ratio of defective products S is extremely small without being caught on the turrets 6 (FIG. 1) and 7 and the tables 8, 9 and 10, and processing can be continued. .
[0012]
Therefore, according to the present invention, even when the product is provided with a projection, such as when the product is bent downward, the processing can be continued without being caught on the turret or the table.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. First, a turret punch press, which is a common device for implementing the first invention (FIGS. 2 and 3), the second invention (FIGS. 4 and 5), and the third invention (FIGS. 6 to 10), A description will be given based on FIG.
[0014]
The turret punch press 1 shown in FIG. 1 has an upper turret 6 and a lower turret 7, and a punch P and a die D are concentrically arranged on the upper turret 6 and the lower turret 7, as is well known. By rotating the turrets 6 and 7 synchronously, predetermined dies P and D are selected at the processing position K.
[0015]
Further, an upper ram 5 for pressing the punch P is provided on the upper frame 2 immediately above the punch P at the processing position K.
[0016]
Further, a lower ram 16 is provided on the lower frame 3 immediately below the die D at the processing position K. The lower ram 16 is, for example, a cut-and-raised bending mold according to a third invention of the present invention described later. (FIG. 6).
[0017]
A center table 8 is fixed at the center of the lower frame 3, and a carriage base 12 is arranged so as to straddle the center table 8.
[0018]
A ball screw 13 of a Y-axis motor My is screwed into the carriage base 12, and when the Y-axis motor My is driven, the ball screw 13 rotates. It moves in the axial direction.
[0019]
A carriage 11 on which a clamp 15 is mounted is slidably coupled to the carriage base 12, and a ball screw 14 of an X-axis motor Mx is screwed into the carriage 11, and when the X-axis motor Mx is driven, the ball screw 14 Rotates, and the carriage 11 moves in the X-axis direction.
[0020]
With this configuration, the clamp 15 is moved in the X-axis direction and the Y-axis direction, and the workpiece W gripped by the clamp 15 is positioned at the processing position K. At the processing position K, for example, a bending die (FIG. 6) When selected, the upper ram 5 and the lower ram 16 (FIG. 1) are operated to operate the bending punch chip 20 (FIG. 6) and the bending die chip 21 that constitute the mold, thereby to be described later. A predetermined bending is applied to the product S connected to the work W via the half-opening connecting portion J (for example, FIG. 3B) (for example, FIGS. 3C and 3D). .
[0021]
(1) Regarding the first invention.
The first invention is a bending method in a punch press. Hereinafter, the first invention implemented using the turret punch press (FIG. 1) will be described in detail with reference to FIGS.
[0022]
(1) -A micro joint processing.
First, in step 101 of FIG. 2, micro joint processing is performed.
[0023]
As is well known, this microjoining process cuts a contour around a region where the product S is to be formed on the workpiece W (the left diagram in FIG. 3A), and cuts the product S. This is a process of leaving only the connecting portion j which is a micro joint connected to the work W.
[0024]
In this case, at the processing position K (FIG. 1), the punching dies P and D having the cutting edge t of a predetermined shape are selected (the right figure in FIG. 3A), and the work W is moved to the processing position K. After the positioning, only the upper ram 5 is actuated, and the molds P and D are used to continuously punch around the product S region, whereby the above-described microjoining is performed.
[0025]
(1) -B Half shear joint processing.
Next, in step 102 of FIG. 2, half shear joint processing is performed.
[0026]
In this half-shear joint processing, half-shear processing is performed on the connecting portion j, which is the microjoint, that is, the connecting portion j described above is not cut out completely from the work W (left diagram in FIG. This is a process of forming a half-punched connection portion J by punching (FIG. 3B).
[0027]
In this case, at the processing position K (FIG. 1), the same dies P and D for punching as described above are selected (right diagram in FIG. 3B), but the positional relationship with the workpiece W is determined by the dies. The cutting edges t of P and D are set so as to straddle the connecting portion j and the work W.
[0028]
For example, if the direction of the last cutting edge t in the micro joint processing is set to 0 ° (the left figure in FIG. 3A), the mold is rotated by a mold rotating device (not shown) added to the turret punch press (FIG. 1). The dies P and D are rotated by 90 °, and the workpiece W is positioned so that the cutting edges t of the dies P and D after the 90 ° rotation straddle the connecting portion j and the workpiece W as described above. .
[0029]
In this state, the pressure of the upper ram 5 (FIG. 1) for pressing the punch P is reduced, thereby lowering the punch P and lowering the pressure in comparison with the case where the workpiece W is completely punched (FIG. 3A). By adjusting the position of the dead center, half blanking as shown in FIG. 3B becomes possible, and a half blanked connecting portion J is formed.
[0030]
As described above, by forming the semi-open connection portion J (FIG. 3B), the upward bending of the product S described later (FIG. 3C) becomes extremely easy, and the product S is bent downward by ironing. Later (FIG. 3 (D)), even when the work W is carried out of the turret punch press, the semi-open connection portion J can be easily removed, and each product S can be separated from the work W.
[0031]
(1) -C bending.
Next, in step 103 of FIG. 2, the product S is bent upward with the half-cut connection J as a fulcrum. In step 104, the product S portion on the opposite side of the half-cut connection J with respect to the bending line m is pressed downward. Bend.
[0032]
That is, when the half-shear joint processing (step 102 in FIG. 2) is completed using the punching dies P and D (right diagram in FIG. 3B), the bending dies are now processed at the processing position K. Is selected (FIG. 6), and the product S connected via the half blanking connection portion J on the workpiece W (left view in FIG. 3B) is positioned at the processing position K.
[0033]
In this state, as shown in FIG. 3 (C), the product S is bent upward with the half-open connection J as a fulcrum, and as shown in FIG. The product S is bent downward along the bending line m.
[0034]
In this case, as described later, the workpiece W connecting the product S via the half-opening connection portion J is pressed by the punch guide 26 (right diagram in FIG. 3C), and in this state, the product S Since the bending die chip 21 rises from below, the product S is bent upward by being pushed upward.
[0035]
However, when the product S is bent upward, the product S comes into contact with the bending punch chip 20 waiting thereon, and thereafter, the product S moves upward by the cooperation of the ascending die chip 21 and the standby punch chip 20. It can be bent downward while being bent.
[0036]
Therefore, the product S is bent upward while being bent upward.
[0037]
In this way, according to the present invention, the product S is provided with a projection such as the flange F bent downward (FIG. 3D), at which time the product S bends upward. Therefore, even when the product S is carried out, for example, the product S is extremely small in the proportion of defective products without being caught by the turrets 6 (FIG. 1) and 7 and the tables 8, 9 and 10, and processing can be continued. It becomes.
[0038]
(2) Regarding the second invention.
The second invention is a bending method in a punch press different from the first invention, and will be described in detail below with reference to FIGS.
[0039]
(2) -A micro joint processing.
First, in step 201 of FIG. 4, micro joint processing is performed.
[0040]
This microjoining is exactly the same as that of the first invention, and cuts the contour around the area where the product S is to be formed on the work W (the left figure in FIG. 5A), This is a process of leaving only the connecting portion j which is a micro joint for connecting the product S to the workpiece W. Similarly, punching dies P and D are used (right diagram in FIG. 5A).
[0041]
(2) -B Half shear joint processing and downward molding processing.
Next, in step 202 of FIG. 4, half shear joint processing is performed, and in step 203, the product S is formed and a downward forming part T is provided.
[0042]
In this case, the half shear joint processing is also completely the same as the case of the first invention, and after the same punching dies P and D are rotated by, for example, 90 ° as in the micro joint processing (FIG. 5A), the half shear joint processing is performed. After the cutting edges t of the dies P and D after 90 ° rotation and the work W have a predetermined positional relationship (the right figure in FIG. 5B), the connecting portion j is not completely punched out of the work W. This is a process of forming a half-blanked connecting portion J (left diagram in FIG. 5B) by half-blanking.
[0043]
However, unlike the first invention, in the second invention, after the half shear joint processing, the dies P and D for molding are applied to the product S connected to the workpiece W at the half-opening connection part J. Using FIG. 5C, a downward forming portion T is provided on the lower surface of the product S (left diagram in FIG. 5C).
[0044]
(2) -C bending.
Next, in step 204 of FIG. 4, the product S provided with the downwardly shaped portion T is bent upward with the half-blanked connecting portion J as a fulcrum.
[0045]
That is, when the forming process (step 203 in FIG. 4) is completed using the forming dies P and D (the right diagram in FIG. 5C), the bending die is (FIG. 6) At the same time as selecting, the product S, which is connected on the work W via the half-opening connecting portion J (left drawing of FIG. Position.
[0046]
In this state, as shown in FIG. 5 (D), the product S provided with the downwardly formed portion T is bent upward with the half-blanked connection portion J as a fulcrum C.
[0047]
In this case, as will be described later, the half-cut connecting portion J connecting the product S to the workpiece W is pressed by the punch guide 26 (right diagram in FIG. 5C), and in this state, from below the product S. Since the bending die chip 21 rises, the product S is bent upward by being pushed upward.
[0048]
In this way, according to the present invention, the product S is provided with the protrusions such as the downwardly-formed portions T (FIG. 5D), but by bending the product S upward, for example, Even when the product S is carried out, the ratio of the product S as a defective product is extremely small without being caught on the turrets 6 (FIG. 1) and 7 and the tables 8, 9 and 10, and processing can be continued.
[0049]
(3) Regarding the third invention.
[0050]
The third invention is a bending die in a punch press, and will be described in detail below with reference to FIGS.
[0051]
The bending die is composed of a punch P and a die D attached to an upper turret 6 and a lower turret 7 (FIG. 6). The punch P and the die D have a punching die 20 and a die 21 for bending, respectively. are doing.
[0052]
The punch P has a punch guide 26 inserted into an opening 34 of the upper turret 6, and the punch guide 26 is supported by the upper turret 6 via a lift spring 23. A punch head 24 is supported via a stripper spring 22.
[0053]
A punch body 25 is attached to the punch head 24. The punch body 25 extends downward and enters the punch guide 26, and the bending punch tip 20 is attached to the tip thereof.
[0054]
The die D (FIG. 6) is mounted on a die holder 27, and a bending die chip 21 is disposed in a hole 31 of the die D so as to be able to come and go.
[0055]
The die chip 21 is attached to the tip of a moving body 29, and the moving body 29 passes through the opening 32 of the die holder 27 and the opening 33 of the lower turret 7, and the bottom 30 of the moving body 29 is connected to the die holder 27. Is mounted via a spring 28.
[0056]
As shown in the figure, the punch chip 20 and the die chip 21 are attached at positions displaced in a direction perpendicular to the vertical direction (Z-axis direction), for example, in the horizontal direction (X-axis direction) in FIG. The cutting edges 20A and 21B are opposed in the vertical direction.
[0057]
Further, the punch chip 20 protrudes inward (FIG. 7), and the die chip 21 protrudes upward.
[0058]
With this configuration, if the upper ram 5 is actuated (FIG. 6) to press the punch head 24, first, the lift spring 23 bends and the punch guide 26 descends to hold the workpiece W (FIGS. 7 and 8). A)) Then, the stripper spring 22 is bent (FIG. 6) and the punch body 25 is lowered, and the punch chip 20 is also lowered accordingly. At this time, the punch chip 20 is stopped and waits at a predetermined position. (FIG. 8A).
[0059]
Then, in this state, if the lower ram 16 is actuated (FIG. 6) to press the bottom 30 of the moving body 29, the spring 28 is bent and the moving body 29 rises, so that the die tip 21 at the tip thereof also rises. Then, the product S is pushed up (FIG. 8 (B)), and as described later, the product S is bent upward while cooperating with the punch chip 20 waiting at the predetermined position. (FIGS. 8C and 8D).
[0060]
Hereinafter, the operation of the bending die in the punch press having the above configuration will be described with reference to FIGS.
[0061]
(3) -A The operation when bending the product S downward while bending it upward.
In this case, as described in steps 101 to 102 of FIG. 2 and FIGS. 3A to 3B, the half-shear joint processing has already been performed, and the connecting portion for connecting the product S to the work W has been already formed. j (FIG. 3 (A)) is half-punched to form a half-punched connecting portion J (FIG. 3 (B)).
[0062]
First, at the processing position K, the bending dies P and D are selected, the work W is positioned, the upper ram 5 is operated (FIGS. 1 and 6), and the work is moved by the punch guide 26 (FIG. 8A). With W held down, the punch chip 20 is kept waiting above, and the die chip 21 is positioned at the initial position and is brought into contact with the lower surface of the product S.
[0063]
In this case, the punch guide 26 (FIG. 8 (A)) presses the work W portion facing the half blanking connecting portion J, and the punch chip 20 is located above and the die chip 21 is located below the bending line m. ing.
[0064]
In this state, when the lower ram 16 (FIGS. 1 and 6) is operated to raise the die chip 21 (FIG. 8 (B)), the product S is bent upward with the half-cut connecting portion J as a fulcrum C. It comes into contact with the punch chip 20 waiting upward (FIG. 8C).
[0065]
In this case, the part of the product S on the opposite side of the half-cut connection portion J with respect to the bending line m is in contact with the punch chip 20 waiting above (FIG. 8C).
[0066]
Therefore, if the die chip 21 is continuously raised (FIG. 8 (D)), the product S portion on the opposite side to the half blanking connection portion J is pressed down by the punch chip 20 waiting upward, As shown, it is bent downward.
[0067]
At this stage, the processing is completed, and the upper ram 5 is raised (FIG. 6) and the lower ram 16 is lowered, so that the chips 20 (FIG. 8E) and 21 return to their original positions.
[0068]
Thereafter, in a state where the product S provided with the downward flange F (FIG. 8F) and bent upward is connected to the work W at the half-blanking connection portion J, the die S is placed on the turret punch press, for example. FIG. 1) The product S is moved to a predetermined carry-out position, carried out to the outside by an unloader (not shown) or the like, and cuts off the half-cut connecting portion J to separate the product S from the work W.
[0069]
(3) -B Operation when bending the product S provided with the downward molding part T upward.
In this case, as described in steps 201 to 203 and FIGS. 5A to 5C in FIG. 4, the product S that has already been subjected to the molding process and has the downward molded portion T is partially cut. It is assumed that the workpiece W is connected to the work W via the pull-out connection part J.
[0070]
First, at the processing position K, the bending dies P and D are selected, the work W is positioned, and the upper ram 5 is operated (FIGS. 1 and 6) to operate the work with the punch guide 26 (FIG. 9A). With W held down, the die chip 21 is positioned at the initial position and is brought into contact with the lower surface of the product S.
[0071]
In this case, the punch guide 26 (FIG. 9A) presses the half-punched connecting portion J, but the punch chip 20 is not used.
[0072]
In this state, when the lower ram 16 (FIGS. 1 and 6) is actuated to raise the die chip 21 (FIG. 9B), the downwardly formed portion T is provided with the half-cut connecting portion J as a fulcrum C. The product S is bent upward.
[0073]
At this stage, the processing is completed, and the upper ram 5 is raised (FIG. 6) and the lower ram 16 is lowered, so that the punch guide 26 and the die chip 21 (FIG. 9C) return to their original positions.
[0074]
Thereafter, the product S provided with the downward forming portion T (FIG. 9D) and bent upward is connected to the work W at the half-opening connection portion J, and is then moved from the die D to, for example, a turret punch press. (FIG. 1) The product S is moved to a predetermined carry-out position, carried out to the outside by an unloader (not shown) or the like, and cuts the half-cut connecting portion J to separate the product S from the work W.
[0075]
As described above with reference to FIGS. 8 and 9, according to the present invention, the use of the bending dies P and D (FIG. 6) allows the downward flange F or (FIG. 8 (F)) or the downward molding portion T to be formed. (FIG. 9 (D)), the product S is bent upward. Therefore, for example, even when the product S is moved from the die D to a predetermined unloading position on the turret punch press after processing. , The turrets 6 (FIG. 1) and 7 and the tables 8, 9 and 10 are not caught, so that the product S hardly becomes defective and the processing can be continued.
[0076]
(3) -C Operation when the work W is bent upward by ironing.
In this case, as shown in FIG. 10A, for example, a flange F 'is formed on the work W, and the flange F' is to be bent upward along the bending lines m1 and m2.
[0077]
First, at the processing position K, the bending dies P and D are selected, the work W is positioned, and the upper ram 5 is operated (FIGS. 1 and 6) to operate the work with the punch guide 26 (FIG. 10B). With W held down, the punch chip 20 is made to stand by above the bending line m1, and the die chip 21 is brought into contact with the lower surface of the work W immediately below the bending line m1.
[0078]
In this state, the upper ram 5 and the lower ram 16 (FIGS. 1 and 6) are actuated to lower the punch chip 20 (FIG. 10C) to hold the bending line m1 and raise the die chip 21. , Flange F 'is bent upward along bending line m1.
[0079]
Then, from the state of FIG. 10C, the workpiece W is moved, for example, to the left side so as to position the bending line m2 at the processing position K by raising the punch P side and lowering the die chip 21 once, and then again. When the die P is lowered while the punch P is lowered (FIG. 10D) and the punch chip 20 presses the bending line m2, the flange F 'is bent upward along the bending line m2. And become U-shaped.
[0080]
Thereafter, from the state shown in FIG. 10D, the punch P side is slightly raised so as not to interfere with the horizontal portion of the U-shaped flange F ', and the die chip 21 is lowered. If the punch P is moved further (FIG. 10 (E)) and the punch P is further raised and returned to the original position, the processing is completed.
[0081]
As a result, on the die D (FIG. 10 (F)), a U-shaped flange F ′ which is bent upward along the bending lines m1 and m2 remains, and is processed by the turret punch press (FIG. 1). Is completed, the work W is discharged to the outside in this state.
[0082]
If the flanges F 'shown in FIG. 10A are connected to a large number of works W, the work W is positioned and the positions shown in FIGS. 10B to 10E are changed. Repeat the operation.
[0083]
【The invention's effect】
As described above, according to the present invention, the first invention and the second invention for performing a predetermined bending on a product connected to a work through a half-opening connection portion, and a bending die used in that case. According to the third aspect, even when the product is provided with a projection, such as when the product is bent downward, there is an effect that the processing can be continued without being caught on the turret or the table.
[0084]
Further, according to the bending die of the present invention, there is also an effect that the workpiece is bent upwards even if there is no half-punched connecting portion.
[0085]
[Brief description of the drawings]
FIG. 1 is an explanatory view of an apparatus for carrying out the present invention.
FIG. 2 is a flowchart for explaining the operation of the first invention.
FIG. 3 is an explanatory view of each step of the first invention.
FIG. 4 is a flowchart for explaining the operation of the second invention.
FIG. 5 is an explanatory view of each step of the second invention.
FIG. 6 is a view showing a third invention.
FIG. 7 is a view showing a relationship between a bending punch chip 20 and a bending die chip 21 of the third invention.
FIG. 8 is a diagram illustrating a first operation of the third invention.
FIG. 9 is a diagram illustrating a second operation of the third invention.
FIG. 10 is a diagram illustrating a third operation of the third invention.
FIG. 11 is an explanatory diagram of a configuration of a conventional technique.
FIG. 12 is an explanatory diagram of a problem in the related art.
[Explanation of symbols]
Reference Signs List 1 turret punch press 2 upper frame 3 lower frame 5 upper ram 6 upper turret 7 lower turret 8 center table 9, 10 side table 11 carriage 12 carriage base 13, 14 ball screw 15 clamp 16 lower ram 20 punch punch 21 for bending 21 Bending die chip 22 Stripper spring 23 Lift spring 24 Punch head 25 Punch body 26 Punch guide 27 Die holder 28 Spring 29 Moving body 30 Bottom 31 Holes 32, 33, 34 Opening C Support point D Die J Half-punched connection part P Punch S Product W work

Claims (7)

(1) A half-punched connection part is formed by half-punching the connection part connecting the product to the workpiece,
(2) A bending method in a punch press, wherein, while bending the product upward with the half-open connection portion as a fulcrum, a product portion on the opposite side of the half-open connection portion with respect to the bending line is bent downward. . A bending method in a punch press, wherein a product provided with a downwardly formed portion is bent upward about a half-punched connection portion as a fulcrum. It has a punching chip for bending and a die chip for bending, both chips are movable in the vertical direction, and each chip is mounted at a position displaced in a direction orthogonal to the vertical direction, and each cutting edge is A bending die in a punch press, characterized by being opposed in a direction. 4. The bending die according to claim 3, wherein the edge of the punch tip projects inward, and the edge of the die tip projects upward. With the punch chip waiting above, the die chip is lifted, and the product is bent upward with the half-punched connection part connecting the product to the workpiece, while the product is bent upward, and the opposite side of the bending line with respect to the bending line. 4. A bending die for a punch press according to claim 3, wherein the product part is bent downward. The bending die according to claim 3, wherein the die chip is raised and the product is bent upward with a half-punched connection part connecting the product provided with the downwardly formed part to the work as a fulcrum. The bending die according to claim 3, wherein the die chip bends the work W upward while the punch chip presses the work.

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