JP6100546B2 - Shear punching method and shear punching apparatus - Google Patents

Description

  The present invention relates to a shear punching method and a shear punching apparatus.

  Processed parts formed from metal plate materials (workpieces) are used in many fields, and various processing methods are known. As a typical processing method used in processes such as forming the outer shape of a part, drilling, and separating the part from a plate material, there is a shear punching process. In the shear punching process, a plate material is sandwiched between a punch and a die to apply an external force exceeding the breaking limit, and the plate material is sheared by an edge portion of the punch and the die. During this shearing, sagging and burrs are generated on the cut surface of the component. The sagging is a deformed portion formed by pulling the edge portions of the punch and die into the plate material, and the thickness of the cut surface is smaller than the original thickness of the plate material due to sagging. . In order to adjust the cut surface, shaving may be performed by inserting a cutting die from the opposite side of the punch in the first shearing process. At this time, the sagging generated in the shearing process is pushed back to some extent, Since the processing is performed on the portion that is, the thickness of the cut surface portion is not restored.

  There is a demand to minimize the sag in the cut surface portion of the part formed by shear punching. For example, when a gear is formed by a cut surface portion of a part, it is desirable to minimize the reduction in wall thickness due to shear punching in order to ensure the strength of the gear and to realize power transmission by reliable engagement. Fine blanking (precision shearing), which improves the restraint of the plate material during processing, is known as a technique for suppressing sag and burrs in shear punching, but the thickness of the cut surface is simpler and less expensive. A processing method and a processing apparatus capable of ensuring the above are desired.

JP 2011-45900 A

  The present invention has been made in view of the above problems, and a processing method and a processing apparatus that can easily and inexpensively reduce the thinning of a cut portion caused by shear punching processing on a workpiece of a metal plate. The purpose is to provide.

The present invention relates to a processing method and a processing apparatus for forming a molded product by shear punching from a workpiece that is a metal plate. In the aspect of the processing method, a primary cut surface is formed by penetrating the workpiece into the workpiece, and the workpiece is bent toward the edge of the workpiece facing the primary cut surface in the advancing direction of the punch. A step of forming a bent edge; a step of cutting a primary cut surface of the workpiece by a cutting die that contacts the workpiece from the side opposite to the punch, and a step of deforming the bent edge in a direction to restore the bending ; and, the step of punching out the molded article from the workpiece by a secondary cutting surface along the primary cutting surface; have a, it comprises a die punch supporting the workpiece has a insertable recess, the recess of the die A bent edge portion is formed along the inclined surface portion formed at the periphery of the opening, and the inclined surface portion has a component that is perpendicular to the direction in which the punch proceeds rather than a component in the direction in which the punch proceeds .

  The cutting die may be pulled out at a half punching position that does not penetrate the workpiece.

In an aspect of the processing apparatus, a die that supports a workpiece; a punch that is inserted into a recess formed in the die and penetrates the workpiece to form a primary cut surface; formed at the periphery of the opening of the recess in the die An inclined surface portion that forms a bent edge bent toward the advancing direction of the punch at the edge of the workpiece facing the primary cutting surface when the workpiece is clamped between the punch and the die; A cutting die that abuts the workpiece from the opposite side, cuts the primary cut surface of the workpiece, and presses in a direction to restore the bending of the bending edge; and a secondary along the primary cut surface punching means for punching the molded product from the workpiece by the cutting surface; have a inclined surface portion, characterized in that the larger the traveling direction component perpendicular punch than components in the traveling direction of the punch.

According to the shear punching processing method and the shear punching processing apparatus of the present invention, when the primary cut surface is formed, a bending edge that is bent toward the advancing direction of the punch is formed on the workpiece, and then the cutting die is formed. Since the pressing is performed in the direction of restoring the bent edge portion of the work material by the cutting process, the reduction in the thickness of the cut surface portion of the work material can be reduced. And the molded product which suppressed the reduction | decrease in the thickness by sagging is obtained by punching a molded product from a workpiece by the secondary cut surface along a primary cut surface. The inclined surface portion of the die that forms the bending edge of the workpiece has a component that is perpendicular to the direction of punch movement rather than the component in the direction of punch movement. Workability when deforming is improved.

It is a top view of the sector gear which is a molded article formed with the processing method and processing apparatus of this invention. It is a top view which shows the process of the shear punching process which forms the sector gear of FIG. It is sectional drawing which shows a part of processing apparatus and workpiece in a 1st process in alignment with the sectional line A of FIG. It is sectional drawing which shows a part of processing apparatus and workpiece in a 2nd process which follows the cross-sectional line B of FIG. It is sectional drawing which shows a part of processing apparatus and workpiece in a 3rd process in alignment with sectional line C of FIG. It is sectional drawing of the gear tooth of the sector gear in alignment with the sectional line D of FIG.

  The present invention will be described based on an embodiment in which the sector gear 10 shown in FIG. The sector gear 10 has gear teeth 13 having a plurality of projections and depressions on the outer edge of a fan-shaped gear plate portion 12 centered on the circular hole 11, and an elongated hole 14 is formed between the circular hole 11 and the gear plate portion 12. Have. The sector gear 10 further has an arm portion 15 that protrudes in the outer diameter direction from the gear plate portion 12 in the radial direction around the circular hole 11, and a circular hole 16 is formed near the tip of the arm portion 15. . The sector gear 10 is a component of a lifter mechanism that changes the height position of the seat of an automobile. However, the details of the lifter mechanism are not related to the present invention, and thus the description thereof is omitted.

  A part of the manufacturing process of the sector gear 10 is conceptually shown in FIG. The sector gear 10 is formed by subjecting a workpiece 20 made of a metal plate material to shear punching using a progressive press device. In the progressive press apparatus, the workpiece 20 is sequentially fed in the direction of arrow F in FIG. 2, and the sector gear 10 is formed through the first step S1, the second step S2, and the third step S3. In the first step S <b> 1, a pilot hole 21 that is a prototype portion of the gear teeth 13 in the sector gear 10 is formed in the workpiece 20. In the second step S2, a shaving process is performed on the pilot hole 21 of the workpiece 20, and in the third step S3, the outer shape of the sector gear 10 is punched out. In the processing apparatus of the present embodiment, two sector gears 10 are formed at the same time. However, the present invention is not limited to this, and when the sector gears 10 are formed one by one, or three or more sector gears 10 are formed. The present invention can also be applied to the case of simultaneous formation. Hereinafter, the details of each step will be described with reference to FIGS. In the following description, the upper side in FIGS. 3 to 5 is defined as the upper side and the lower side is defined as the lower side.

As shown in FIG. 3, in the first step S <b> 1, punching of the prepared hole 21 is performed using the prepared hole die 30, the holder 31, the prepared hole punch 32, and the punch receiver 33. A recess 30a having a cross-sectional shape corresponding to the shape of the pilot hole 21 is formed in the die 30 for the pilot hole, and a convex portion 32a having a cross-sectional shape corresponding to the recess 30a is formed at the lower end of the punch 32 for the pilot hole. Yes. The holder 31 is formed with a guide hole 31a into which the pilot hole punch 32 is slidably inserted in the vertical direction, and the punch receiver 33 is supported in the concave part 30a of the pilot hole die 30 so as to be slidable in the vertical direction. The pilot hole die 30 and the holder 31 are formed with a clamping surface 30b and a clamping surface 31b facing each other, and the pilot hole punch 32 and the punch receiver 33 are formed with a clamping surface 32b and a clamping surface 33a facing each other. . Each of the clamping surfaces 30b, 31b, 32b, and 33a is a horizontal plane. The prepared hole die 30 is further formed with an inclined surface portion 30c at a boundary portion between the concave portion 30a and the clamping surface 30b. The inclined surface portion 30c has an inclined shape that gradually goes downward as it approaches the recess 30a. As shown in FIG. 3, the inclined surface portion 30 c has a direction perpendicular to the traveling direction of the pilot hole punch 32 (left and right direction in the drawing) rather than a component in the traveling direction of the pilot hole punch 32 (up and down direction in the drawing). The component has a larger shape. The pilot hole punch 32 has an edge portion V1 at the peripheral portion of the clamping surface 32b at the lower end of the convex portion 32a. The pilot hole die 30 has an edge portion V2 at a boundary portion between the concave portion 30a and the inclined surface portion 30c.

  The pilot hole die 30 is fixed in the press device as a lower mold. The holder 31 is biased downward by a biasing member (not shown) such as a spring, and the workpiece 20 is sandwiched and fixed between the sandwiching surface 30b and the sandwiching surface 31b. The pilot hole punch 32 is attached as an upper die to a slider (not shown) that is movable in the vertical direction in the press device, and moves in the vertical direction along with the slider. The punch receiver 33 is biased upward by a biasing member such as a spring, and the clamping surface 33a abuts on the workpiece 20 from below.

  In the first step S1, in the state where the workpiece 20 supported on the clamping surface 30b of the pilot hole die 30 is sandwiched and fixed by the clamping surface 31b of the holder 31, the slider to which the pilot hole punch 32 is attached is moved downward. Move to. Then, the workpiece 20 is pinched by the edge portion V1 of the pilot hole punch 32 and the edge portion V2 of the pilot hole die 30, the edge portion V1 bites into the upper surface side of the workpiece 20, and the edge portion V2 is covered. It bites into the lower surface side of the workpiece 20. During this biting, a part of the workpiece 20 is drawn and deformed, and sagging R1 occurs on the upper surface side where the edge portion V1 bites, and sagging R2 occurs on the lower surface side where the edge portion V2 bites. When the lower hole punch 32 continues to descend and the shear load by the convex portion 32a (edge portion V1) and the concave portion 30a (edge portion V2) increases, the blank portion 20a in which the sagging R1 is formed in the workpiece 20; A shearing surface is formed at the boundary portion with the punched portion 20b where the sag R2 is formed, and a crack is generated. When the pilot hole punch 32 further descends, the convex portion 32a penetrates the crack on the blank portion 20a side, and the concave portion 30a penetrates the crack on the punched portion 20b side, a fracture surface is formed following the shear surface, and punching is performed. The part 20b is stamped and separated from the blank part 20a. The shear surface and the fracture surface on the blank portion 20a side form the prepared hole 21 as the primary cut surface K1. The punch receiver 33 is moved downward while following the lowering operation of the pilot hole punch 32 while sandwiching the punched portion 20b between the punch hole 32b and the clamping surface 32b of the pilot hole punch 32. When the formation of the prepared hole 21 is completed by punching the punched portion 20b, the slide of the press device is raised to raise the prepared hole punch 32, and the recessed portion 30a of the prepared hole die 30 and the blank portion 20a of the workpiece 20 (lower The convex part 32a is pulled out from the hole 21).

  In the first step S1 described above, in the blank portion 20a of the workpiece 20, on the lower surface side opposite to the upper surface side where the sag R1 is formed, the downward direction along the shape of the inclined surface portion 30c in the pilot hole die 30 is reduced. An escape protrusion T1 is formed. As can be seen from the comparison of the cut surface portions of the blank portion 20a and the punched portion 20b in FIG. 3, the thickness of the blank portion 20a is not reduced by the compression accompanying the formation of the sagging R1 by forming the relief protrusion T1. The wall thickness is generally kept uniform up to the edge facing the pilot hole 21. That is, the edge part which faces the pilot hole 21 in the blank part 20a of the workpiece 20 has a mold configuration in which it is formed as a bent edge part which is bent toward the traveling direction of the pilot hole punch 32. This prevents the thickness of the primary cut surface K1 (the pilot hole 21) of the blank portion 20a from being reduced. The relief projecting portion T1 is formed as a relief shape portion that projects to the back surface side of the sag R1 to prevent thinning by using a clamping pressure during shearing that generates the sag R1 on the workpiece 20, and is shear punched. It is different from the irregular burrs formed on the opposite side of the sagging.

  As shown in FIG. 4, in the second step S <b> 2, a shaving process (crushing process) is performed on the primary cut surface K <b> 1 that forms the lower hole 21 using the lower holder 40, the upper holder 41, and the cutting die 42. . The lower holder 40 has a cross-sectional shape similar to that of the lower hole die 30, and is positioned at a guide hole 40 a facing in the vertical direction, a sandwiching surface 40 b facing upward, and a boundary portion extending from the sandwiching surface 40 b to the guide hole 40 a. It has the inclined surface part 40c of the shape which follows the escape protrusion part T1 of the workpiece 20. The upper holder 41 has a clamping surface 41 a that faces the clamping surface 40 b of the lower holder 40. The clamping surface 40b and the clamping surface 41a are horizontal planes parallel to each other. In a state where the blank portion 20a of the workpiece 20 is clamped by the clamping surface 40b of the lower holder 40 and the clamping surface 41a of the upper holder 41, the escape protrusion T1 of the workpiece 20 is supported on the inclined surface portion 40c.

  The cutting die 42 is supported in the guide hole 40a of the lower holder 40 so as to be slidable in the vertical direction, and a convex portion 42a having a cross-sectional shape corresponding to the lower hole 21 is formed on the upper end portion of the cutting die 42. The edge part V3 is provided in the peripheral part of the upper end surface 42b in the upper end of 42a. The convex portion 42a of the cutting die 42 is set to have a slightly larger cross-sectional shape than the pilot hole 21 formed in the first step S1, and when the cutting die 42 is slid upward in the guide hole 40a, the edge portion V3 contacts the peripheral portion of the pilot hole 21 on the lower surface side of the workpiece 20, that is, the escape protrusion T1 that forms the bent edge.

  The lower holder 40 is fixed in the press device, and the upper holder 41 is biased downward by a biasing member (not shown) such as a spring, and the workpiece 20 is sandwiched between the clamping surface 40b and the clamping surface 41a. Fix with. The cutting die 42 is attached to a slider (not shown) that is movable in the vertical direction in the press device, and moves in the vertical direction along with the slider.

In the second step S2, the slider to which the cutting die 42 is attached is moved upward in a state where the blank portion 20a of the workpiece 20 is sandwiched between the lower holder 40 and the upper holder 41. Then, the cutting edge 42 of the cutting die 42 thinly cuts the primary cut surface K1 of the prepared hole 21 formed in the first step S1, and the cutting surplus protruding above the cutting region to the inner peripheral side of the prepared hole 21 is performed. The meat part P1 is formed. Further, in this cutting process, an upward pushing force (a crushing force between the cutting die 42 and the upper holder 41) acts on the bent edge portion of the peripheral edge of the prepared hole 21, and the upper surface side of the workpiece 20 Then, the amount of sagging R1 is reduced by being pressed upward. In the first step S1, since the bent edge (relief protrusion T1) of the peripheral edge of the pilot hole 21 is formed in a shape corresponding to the inclined surface portion 30c of the pilot hole die 30, the cutting die 42 contacts the bent edge. Easy to touch and push up. On the other hand, on the lower surface side of the workpiece 20, the edge portion V <b> 3 of the cutting die 42 bites into and pushes upward, but a relief projection portion T <b> 1 that projects downward is formed in advance at the portion where the edge portion V <b> 3 bites. Therefore, the pushing-up force by the cutting die 42 acts as a force for reducing the downward projecting amount of the escape projecting portion T1, and no sagging occurs on the lower surface side of the workpiece 20. As a result, the bent edge facing the pilot hole 21 of the workpiece 20 is restored to the cross-sectional shape close to the initial state before the punching process of the first step S1.

  As shown in FIG. 4, the upward movement of the cutting die 42 is stopped at a half punching position before the upper end surface 42 b of the convex portion 42 a comes into contact with the holding surface 41 a of the upper holder 41. When the half punching position is reached, the slide of the press device is lowered, the cutting die 42 is pulled down, and the convex portion 42 a is pulled out from the prepared hole 21.

  As shown in FIG. 5, in the third step S <b> 3, the sector gear 10 is trimmed using the contour die 50, the holder 51, the contour punch 52, and the punch receiver 53. The outer die 50 is formed with a concave portion 50a having a cross-sectional shape corresponding to the outer shape of the sector gear 10, and a lower end portion of the outer punch 52 is formed with a convex portion 52a having a cross-sectional shape corresponding to the concave portion 50a. . The holder 51 is formed with a guide hole 51a for inserting the outer shape punch 52 so as to be slidable in the vertical direction, and the punch receiver 53 is supported in the recess 50a so as to be slidable in the vertical direction. The outer die 50 and the holder 51 are formed with a sandwiching surface 50b and a sandwiching surface 51b facing each other, and the outer punch 52 and the punch receiver 53 are formed with a sandwiching surface 52b and a sandwiching surface 53a facing each other. Each of the clamping surfaces 50b, 51b, 52b and 53a is a horizontal plane. The outline punch 52 has an edge portion V4 at the peripheral portion of the clamping surface 52b at the lower end of the convex portion 52a. The outer die 50 has an edge portion V5 at the boundary between the recess 50a and the clamping surface 50b.

  The outer die 50 is fixed as a lower mold in the press apparatus. The holder 51 is biased downward by a biasing member (not shown) such as a spring, and the blank portion 20a of the workpiece 20 is sandwiched and fixed between the sandwiching surface 50b and the sandwiching surface 51b. In the cross-sectional position of FIG. 5, only a part of the peripheral edge of the pilot hole 21 is shown in the blank portion 20 a, but a wide area other than the punched portion 20 c that is actually punched as the sector gear 10 is an outer die 50 and a holder. 51. The outer shape punch 52 is attached as an upper die to a slider (not shown) that can be moved in the vertical direction by a press device, and moves in the vertical direction along with the slider. The punch receiver 53 is urged upward by an urging member such as a spring, and the clamping surface 53 a comes into contact with the workpiece 20.

  In the third step S3, the workpiece 20 supported on the clamping surface 50b of the outer die 50 is clamped by the clamping surface 51b of the holder 51, and the slider to which the outer punch 52 is attached is moved downward. Let Then, the workpiece 20 is pressed between the edge portion V4 of the outer shape punch 52 and the edge portion V5 of the outer shape die 50, and a shearing load is applied. The outer shape punch 52 is further lowered and the edge portion V4 becomes the edge portion. When passing the position facing V5, the punched portion 20c sandwiched between the outer punch 52 and the punch receiver 53 is secondarily cut from the blank portion 20a sandwiched between the outer die 50 and the holder 51 in the workpiece 20. It is punched along the surface K2 and separated (FIG. 5). The separated punched portion 20 c becomes the sector gear 10. As shown in FIG. 5, in the third step S3, the thin portion near the pilot hole 21 including the surplus cutting portion P1 and the primary cut surface K1 remains on the blank portion 20a side, which is the peripheral portion of the punched portion 20c. The outer shape of the gear teeth 13 is formed by the next cut surface K2. Unlike the formation of the pilot hole 21 in the first step S1, the formation of the gear teeth 13 in the third step S3 is performed by punching a thin portion between the pilot hole 21 (primary cutting surface K1) and the secondary cutting surface K2. As a result, a large deformation unlike the sag R1 in the first step S1 does not occur in the peripheral portion facing the secondary cut surface K2 in the punched portion 20c.

  As shown in FIG. 2, the pilot hole 21 formed in the first step S1 and the second step S2 includes two prototype portions of the gear teeth 13 in the sector gear 10 in a symmetrical positional relationship, In the third step S3, two sector gears 10 are simultaneously punched and formed with one pilot hole 21 interposed therebetween. When the outer shape punching of each sector gear 10 is completed, the slide of the press device is raised to pull up the outer shape punch 52, and the convex portion 52 a is pulled out from the concave portion 50 a of the outer shape die 50 and the blank portion 20 a of the workpiece 20.

  The circular hole 11, the long hole 14, and the circular hole 16 in each sector gear 10 are formed by a predetermined process in the progressive press apparatus. The formation timing can be arbitrarily set, and may be formed before the outer shape punching of the sector gear 10 in the third step S3 or after the outer shape punching.

  FIG. 6 shows a cross-sectional shape of the gear teeth 13 in the sector gear 10 formed through the above steps. The surface of the gear teeth 13 (the upper surface side of the workpiece 20 in the first step S1 to the third step S3) is directed from the tooth bottom side to the tooth tip side following the flat surface portion M1 that maintains the shape before processing. In order (refer to FIG. 1 for the definition of the tooth bottom and the tooth tip), it has a first surface N1, a second surface N2, and a third surface N3. The first surface N1 is a surface that is inclined downward as it goes from the bottom side of the gear tooth 13 toward the tooth tip side. The second surface N2 is a surface that is formed continuously with the first surface N1 and is inclined upward as it goes from the bottom side of the gear tooth 13 toward the tooth tip side. The third surface N3 is a surface that is formed continuously with the second surface N2 and is inclined downward as it goes from the bottom side of the gear tooth 13 toward the tooth tip side. The first surface N1 and the second surface N2 form a recess G1 that makes the gear teeth 13 thinner than the formation portion of the flat surface portion M1, and a flat surface is formed between the second surface N2 and the third surface N3. A convex portion G2 having a height position substantially the same as the portion M1 is formed. On the other hand, the back surface of the gear teeth 13 (the lower surface side of the workpiece 20 in the first step S1 to the third step S3) is a flat portion M2 substantially parallel to the flat portion M1.

  In the first step S <b> 1 described above, the sagging R <b> 1 is formed on the front surface (upper surface) side of the workpiece 20 and the escape protrusion T <b> 1 is formed on the rear surface (lower surface) side. A peripheral edge portion of the pilot hole 21 to be a prototype is a downward bending edge portion. The sagging R1 at the bent edge is formed as a region from the first surface N1 to the two-dot chain line U1 in FIG. In the subsequent second step S2, as shown by a two-dot chain line U2 in FIG. 6, the bending edge portion is pushed back upward (squeezed up) to form the cutting surplus portion P1. At this stage, the second surface N2 is formed. By the punching process in the third step S3, the tooth tip side is pushed up further than the second surface N2 to form the convex portion G2 and the third surface N3, and the gear teeth having a cross section shown by a solid line in FIG. 13 The gear gear 13 in the completed state has a convex portion G2 so that a thickness comparable to that of the workpiece 20 before processing is secured in the tooth tip portion, and the meshing rate with respect to the gear to be meshed with the sector gear 10 Is high (the amount of meshing is large), and the structure is excellent in strength. Moreover, the gear tooth 13 can be formed by press working by forming the concave portion G1 on the tooth bottom side of the convex portion G2, and the manufacturing cost of the sector gear 10 can be suppressed. .

  As described above, according to the shear punching processing method and processing apparatus according to the present invention, when the prepared hole 21 (primary cutting surface K1) is formed in the workpiece 20, the punch 32 is bent toward the traveling direction. The bending edge is formed, and then pressed by a cutting process by the cutting die 42 in a direction to restore the bending edge of the workpiece 20, and finally the workpiece is cut by the secondary cutting plane K2 along the primary cutting plane K1. By punching the punched portion 20c from 20, the reduction in the thickness of the cut surface portion of the sector gear 10 formed from the workpiece 20 can be reduced. As a processing apparatus, the inclined surface portion 30c is formed in the pilot hole die 30 used when forming the primary cut surface K1, and the inclined surface portion 40c having a shape corresponding to the relief protrusion T1 formed by the inclined surface portion 30c is provided. This can be realized with a simple configuration of forming the lower holder 40, and an excellent effect can be obtained in terms of cost of the processing apparatus.

  Although the present invention has been described based on the illustrated embodiment, the present invention is not limited to the illustrated embodiment, and can be improved or modified without departing from the gist of the invention. For example, the present invention is suitable for forming a gear portion such as the gear teeth 13 in the sector gear 10 of the illustrated embodiment, but can be widely applied to a workpiece other than the sector gear.

  Moreover, the specific structure of the metal mold | die in each processing process can also be made different from illustration embodiment. For example, it is possible to adopt a mold configuration in which the punch receiver 33 in the first step S1 and the punch receiver 53 in the second step S3 are omitted.

DESCRIPTION OF SYMBOLS 10 Sector gear 11 16 Circular hole 12 Gear board part 13 Gear tooth 14 Long hole 15 Arm part 20 Work material 20a Blank part 20b Punching part 21 Pilot hole 30 Pilot hole die 30a Recess 30b Clamping surface 30c Inclined surface part 31 Holder 31a Guide Hole 31b Clamping surface 32 Pilot hole punch 32a Protruding portion 32b Punching surface 33 Punch receiver 33a Clamping surface 40 Lower holder 40a Guide hole 40b Clamping surface 40c Inclined surface portion 41 Upper holder 41a Clamping surface 42 Cutting die 42a Convex portion 50 Die 50a Concavity 50b Clamping surface 51 Holder 51a Guide hole 51b Clamping surface 52 Punch 52a Protruding portion 52b Clamping surface 53 Punch receiver 53a Clamping surface G1 Concavity G2 Convex portion K1 Primary cutting surface K2 Secondary cutting surface P1 Cutting surplus portion S1 First step S2 First 2 process S3 3rd process T1 escape protrusion V1 V2 V3 V4 V5 edge

Claims (3)

In a processing method for forming a molded product by shear punching from a workpiece of a metal plate,
A bent edge that is formed by penetrating a punch through the workpiece to form a primary cut surface, and is bent toward an edge of the workpiece facing the primary cut surface in the advancing direction of the punch Forming a step;
Cutting the primary cut surface with a cutting die contacting the workpiece from the opposite side of the punch, and deforming the bent edge in a direction to restore the bending; and the primary cut surface Punching a molded product from the workpiece by a secondary cut surface along the line;
I have a,
A die having a concave portion that supports the workpiece and into which the punch can be inserted, and the bent edge portion is formed along an inclined surface portion formed at the periphery of the opening portion of the concave portion of the die;
The shear punching method according to claim 1, wherein the inclined surface portion has a component that is perpendicular to a direction in which the punch proceeds in a direction larger than a component in the direction in which the punch proceeds . 2. The shear punching method according to claim 1, wherein the cutting die is pulled at a half punching position that does not penetrate the workpiece. In a processing apparatus for forming a molded product by shear punching from a workpiece of a metal plate,
A die that supports the workpiece and has a recess;
A punch that is inserted into the recess of the die and penetrates the workpiece to form a primary cut surface;
The punch proceeds to the edge of the workpiece facing the primary cutting surface when the workpiece is clamped between the punch and the die and formed at the periphery of the opening of the recess of the die. An inclined surface that forms a bent edge that is bent in a direction;
A cutting die that contacts the workpiece from the opposite side of the punch, cuts the primary cut surface, and presses in a direction to restore bending of the bending edge; and 2 along the primary cut surface Punching means for punching a molded product from the workpiece by the next cut surface;
I have a,
The shear punching apparatus according to claim 1, wherein the inclined surface portion has a component that is perpendicular to a direction in which the punch proceeds in a direction larger than a component in the direction in which the punch proceeds .

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