Bending die regeneration method and regenerated bending die

Abstract

To provide a method for restoring a bending die that does not make streaks in a surface of a workpiece therefore not deteriorating appearance quality even bending is performed through coining.SOLUTION: The method for restoring a bending die includes: a build-up step of forming, on a base material (A) of a bending die (K) to be restored having a restoration target surface (Aa) of a shape different from a reference shape, a build-up part (B) for covering the entire restoration target surface (Aa); and a forming step of rotating a grinding wheel (C) having a grinding part (Ca) for grinding the build-up part (B) to form the build-up part (B) into the reference shape and restore the restoration target surface. The grinding part (Ca) of the grinding wheel (C) has a circumferential convex portion (Ca1) bored so as to include an outer appearance end part (Ba) connected to the base material (A) of the build-up part (B). In the forming step, a concave portion (E) that includes an appearance boundary between the base material (A) and the build-up part (B) is formed by the circumferential convex portion (Ca1) in the bending die (K) to be restored.SELECTED DRAWING: Figure 3F

Description

[Technical field]

[0001] The present invention relates to a method for recycling a bending die and a recycled bending die. [Background technology]

[0002] Patent Document 1 describes a method for regenerating a worn die (hereinafter, referred to as a die regeneration method). The die regeneration method described in Patent Document 1 is a method for regenerating a new edge portion of a press punch die by applying build-up welding to an edge portion that has worn or chipped due to use, and then mechanically grinding the welded build-up portion. The method of recycling dies described in Patent Document 1 is not limited to press punch dies, but is commonly used as a method of recycling other dies, and punch dies and die dies for bending dies can also be recycled using this method.

[0003] A conventional method for recycling bending dies will be described with reference to Fig. 7A and Fig. 7B, taking a punch die as a specific example. Fig. 7A is a right side view showing a conventional punch die 101. Fig. 7B is a view for explaining the conventional die recycling method, and Fig. 7B(a) to (c) are side views corresponding to the first to third steps, respectively.

[0004] As shown in FIG. 7A, a conventional punch die 101 has a body portion 111 that is attached to a punch holder, and a cutting edge portion 112 that is formed at the tip of the body portion 111 and that comes into contact with a workpiece. FIG. 7B is an enlarged view of tip region 112A of cutting edge portion 112 in FIG. 7A. Cutting edge portion 112, which has been subjected to multiple bending processes, has a worn surface 112c whose outer shape has been worn away from the outer shape of reference cutting edge line LNa when not in use, as shown by the two-dot chain line in FIG. 7B(a).

[0005] When the wear has progressed to a certain extent, as shown in Fig. 7B(b), metal is welded to form a padded portion 113 having a size and cross-sectional shape that includes the reference cutting edge line LNa. Thereafter, the padded portion 113 is ground to match the external shape of the reference cutting edge line LNa using a punch forming grindstone 105 having a shape corresponding to the reference cutting edge line LNa, to form a recycled punch top 114 shown in Fig. 7B(c). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 7-265972 Summary of the Invention [Problem to be solved by the invention]

[0007] The finishing dimensions of the bending die are set with a tolerance that takes into account variations in processing during manufacturing within a range that allows performance to be achieved as specified. Specifically, the punch die 101 is set with a tolerance of, for example, "+0 mm to -0.05 mm" for the dimension in the thickness direction. Meanwhile, the grinding surface shape of the punch forming grindstone 105 shown in Fig. 7B(b) is designed to form a grinding surface of ±0 mm corresponding to the reference cutting edge line LNa. Therefore, if the pre-use dimensions of the cutting edge portion 112 of the punch die to be recycled are formed near the upper limit of the tolerance, the cutting edge portion 112 and the recycled punch top portion 114 formed by grinding the padding portion 113 using the punch forming grindstone 105 will be formed with a continuous surface without any steps, as shown in Figure 7B(c).

[0008] In contrast, if the thickness dimension of the cutting edge 112 before use is formed near the lower limit of the tolerance, a gap Δd corresponding to the tolerance is generated between the punch forming grindstone 105 and the cutting edge 112 as shown in FIG. 8A. Then, a ground surface corresponding to the reference cutting edge line LNa is formed on the recycled punch top 114 formed by grinding the padded portion 113, but as shown in FIG. 8B, a steep step 115 with the padded portion 113 side being convex is formed at the end of the padded portion 113. This step 115 is formed along the longitudinal direction of the punch die 101 (the left-right direction shown in FIG. 1). FIG. 8A shows a case where the gap Δd is generated on the left side of the figure, but there are cases where the gap is generated on the right side of the figure or on both sides, and there is a risk that the step 115 is formed on the right side or on both sides.

[0009] The same is true for die molds; if the width of the V-groove portion is biased toward the side with the larger tolerance, there is a risk that a steep step will be formed on at least one of the pair of inclined surfaces of the V-groove portion, causing the build-up portion to become convex.

[0010] If such a step 115 is formed in the cutting edge 112 of the punch 101, which is a bending die, and in the V-groove of the die, the appearance quality of the punch 101 and the die will deteriorate, and if the bending process is so-called coining, a line corresponding to the step 115 will be formed on the surface of the workpiece, which may deteriorate the appearance quality of the workpiece, and therefore an improvement is desired. [Means for solving the problem]

[0011] In order to solve the above problems, one embodiment of the bending die regeneration method of the present invention has the following configuration: That is, the bending die regeneration method includes a build-up step of forming a build-up portion covering the entire surface to be regenerated on a base material of the bending die having a surface to be regenerated that is a shape different from a reference shape, and a shaping step of rotating a grindstone having a grinding part that grinds the build-up portion to shape the build-up portion into the reference shape and regenerate the build-up portion, the grinding part of the grindstone having a peripheral convex part that is carved out to include an external end of the build-up portion that is connected to the base material, and the shaping step forms a recess in the bending die by the peripheral convex part that includes an external boundary between the base material and the build-up portion.

[0012] In this embodiment, by forming a recess that includes the boundary between the base material and the buildup portion, a steep step that makes the buildup portion convex is not formed, and even if the bending process is coining, no line corresponding to the step is formed on the surface of the workpiece, so that the appearance quality is not reduced.

[0013] In order to solve the above problems, one embodiment of the recycled bending die of the present invention is as follows: 1) and 2) It has a configuration. 1) A first portion is formed of a first material and has a substantially plate-like shape, and has a cutting edge or a V-groove portion having a V-shaped cross section formed by a first surface and a second surface at one edge portion; A second portion is provided on the tip side of the cutting edge portion or the V-groove portion and is made of a second material different from the first material, The first surface and the second surface each have a recess formed in a range including an apparent boundary between the first portion and the second portion. 、 a punch die having the cutting edge portion at the first portion, It is a recycled bending mold. 2) A first portion having a substantially plate-like shape formed from a first material and a V-shaped cutting edge or V-groove portion having a V-shaped cross section formed by a first surface and a second surface at one edge portion; A second portion is provided on the tip side of the cutting edge portion or the V-groove portion and is made of a second material different from the first material, The first surface and the second surface each have a recess formed in a range including an apparent boundary between the first portion and the second portion. 、 The first portion and the second portion are smoothly connected by a rounded edge, the second portion is formed of laminated metal powder; a die having the V-groove portion in the first portion; It is a recycled bending mold.

[0014] In this embodiment, since there is a recess that includes the boundary between the first portion and the second portion, a steep step that makes the second portion convex is not formed, and even if the bending process is coining, no line corresponding to the step is left on the surface of the workpiece, so that the appearance quality is not reduced. Effect of the Invention

[0015] According to one embodiment of the bending die recycling method and one embodiment of the recycled bending die of the present invention, no steps are formed in the cutting edge of the punch die and in the V-groove of the die die, so there is no degradation in appearance quality, and even if the bending process is coining, no lines are left on the surface of the workpiece, so there is no degradation in appearance quality. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a perspective view showing the appearance of a punch die 1 which is a first embodiment of the recycled bending die of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view illustrating a method for forming cutting edge portion 12 of punch 1. As shown in FIG. [Figure 3A] FIG. 3A is a cross-sectional view for illustrating a first step of forming a cutting edge portion 12 in a first embodiment of the method for regenerating a bending die of the present invention. [Figure 3B] FIG. 3B is a cross-sectional view for illustrating the second step of shaping cutting edge portion 12 in the first embodiment of the bending die regenerating method. [Figure 3C] FIG. 3C is a cross-sectional view for illustrating the third step of shaping cutting edge portion 12 in the first embodiment of the bending die regenerating method. [Figure 3D] FIG. 3D is a cross-sectional view for illustrating a fourth step of shaping cutting edge portion 12 in the first embodiment of the bending die regenerating method. [Figure 3E] FIG. 3E is a cross-sectional view for illustrating the first step of shaping cutting edge portion 12 in a second embodiment of the bending die regenerating method of the present invention. [Figure 3F] FIG. 3F is a cross-sectional view for illustrating the second step of shaping cutting edge portion 12 in the second embodiment of the bending die regenerating method. [Figure 4] FIG. 4 is a perspective view showing the appearance of a die 2 which is a second embodiment of the recycled bending die of the present invention. [Figure 5A]FIG. 5A is a cross-sectional view for illustrating a first step of forming a V-groove portion 22 in a first embodiment of the bending die recycling method of the present invention. [Figure 5B] FIG. 5B is a cross-sectional view for explaining the second step of forming the V-groove portion 22 in the first embodiment of the bending die recycling method. [Figure 5C] FIG. 5C is a cross-sectional view for illustrating the third step of forming the V-groove portion 22 in the first embodiment of the bending die recycling method. [Figure 5D] FIG. 5D is a cross-sectional view for explaining the fourth step of forming the V-groove portion 22 in the first embodiment of the bending die recycling method. [Figure 6A] FIG. 6A is a plan view showing a punch forming grindstone 5 used in the first and second embodiments of the bending die regenerating method. [Figure 6B] FIG. 6B is a plan view showing the die forming grindstone 6 used in the first and second embodiments of the bending die regenerating method. [Figure 7A] FIG. 7A is a side view showing a punch die 101 of a conventional recycled bending die. [Figure 7B] FIG. 7B is a diagram for explaining a conventional method for regenerating a bending die, and FIG. 7B(a) to (c) are cross-sectional views corresponding to the first to third steps, respectively. [Figure 8A] FIG. 8A is a cross-sectional view showing an example of a forming step of a cutting edge portion 112 in a conventional method for regenerating a bending die. [Figure 8B] FIG. 8B is a perspective cross-sectional view showing cutting edge portion 112 of a conventional recycled bending die. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The recycled bending die of the present invention will be described with reference to Figs. 1 to 6B using a punch die 1 of a first embodiment and a die die 2 of a second embodiment as examples. The punch die 1 and the die die 2 are each included in the recycled bending die K.

[0018] (Punch die 1) FIG. 1 is a perspective view showing the appearance of a punch die 1 which is a first embodiment of the regenerated bending die of the present invention. FIG. 2 is a cross-sectional view for explaining a method for forming the cutting edge portion 12 of the punch die 1. FIG. 3A is a cross-sectional view for explaining a first step of forming the cutting edge portion 12 in the first embodiment of the regenerating method for a bending die of the present invention. FIG. 3B is a cross-sectional view for explaining a second step of forming the cutting edge portion 12 in the first embodiment of the regenerating method for a bending die. FIG. 3C is a cross-sectional view for explaining a third step of forming the cutting edge portion 12 in the first embodiment of the regenerating method for a bending die. FIG. 3D is a cross-sectional view for explaining a fourth step of forming the cutting edge portion 12 in the first embodiment of the regenerating method for a bending die. FIG. 3E is a cross-sectional view for explaining a first step of forming the cutting edge portion 12 in the second embodiment of the regenerating method for a bending die of the present invention. FIG. 3F is a cross-sectional view for explaining a second step of forming the cutting edge portion 12 in the second embodiment of the regenerating method for a bending die. Fig. 6A is a plan view showing a punch forming grindstone 5 used in the first and second embodiments of the bending die regenerating method. Fig. 6B is a plan view showing a die forming grindstone 6 used in the first and second embodiments of the bending die regenerating method. For ease of explanation, the up, down, left, right, front and back directions are defined as the directions shown by arrows in Fig. 1.

[0019] As shown in Fig. 1, the punch die 1 of the recycled bending die K has a punch body 11 as a substantially plate-shaped base material A extending up, down, left, and right, and a cutting edge 12 formed on a lower edge, which is one edge of the punch body 11. The punch body 11 is attached to a punch holder of a bending machine. The punch die 1 moves up and down by the operation of the attached bending machine, and when it descends, the cutting edge 12 comes into contact with the upper surface of a workpiece W (see Fig. 3D) arranged between the punch die 1 and a die 2 (see Fig. 4) described later, and presses the workpiece W downward, thereby bending the workpiece W.

[0020] 1 and 2, the cutting edge 12 is formed in a V-shape having a pair of inclined surfaces tapered downward in a side view. The inclined plane on the front side of the cutting edge 12 is the first inclined surface 12a as a first outer surface, and the inclined plane on the rear side is the second inclined surface 12b as a second outer surface. In the cutting edge 12, the first inclined surface 12a has a first recess 121 extending in the left-right direction at a portion near the tip, and the second inclined surface 12b has a second recess 122 extending in the left-right direction at a portion near the tip. The first recess 121 and the second recess 122 are collectively referred to as recess E.

[0021] As shown in Fig. 2, the first inclined surface 12a and the second inclined surface 12b are formed by grinding with a punch forming grindstone 5. The punch forming grindstone 5 is a grindstone having a cylindrical or disk-shaped base body 50, and a grinding portion 5G having a predetermined grinding surface is formed on the peripheral surface of the base body 50. The predetermined grinding surface has a shape corresponding to the final finished shape of the cutting edge portion 12. The punch forming grindstone 5 is collectively referred to as grindstone C, and the grinding portion 5G is collectively referred to as grinding portion Ca.

[0022] Specifically, the grinding portion 5G has a first concave inclined grinding wheel surface 5a forming the first inclined surface 12a of the cutting edge portion 12 and a second concave inclined grinding wheel surface 5b forming the second inclined surface 12b of the cutting edge portion 12. The first concave inclined grinding wheel surface 5a has a first peripheral convex portion 51 forming the first recess 121 of the cutting edge portion 12, and the second concave inclined grinding wheel surface 5b has a second peripheral convex portion 52 forming the second recess 122 of the cutting edge portion 12. The first peripheral convex portion 51 and the second peripheral convex portion 52 are convex portions formed over the entire circumference in shapes corresponding to the shapes of the first recess 121 and the second recess 122, respectively. The first peripheral convex portion 51 and the second peripheral convex portion 52 are included in the peripheral convex portion Ca1 as a general term.

[0023] The punch forming grindstone 5 is attached to a grinding machine (not shown) and rotates about an axis CL5, and is pressed against the cutting edge portion 12. As a result, the cutting edge portion 12 is formed by grinding into a shape corresponding to the ground portion 5G.

[0024] The worn cutting edge portion 12 is the regeneration target surface Aa, and is regenerated by the bending die regeneration method of the first embodiment described below. In the description, reference will be made to Figs. 3A to 3D.

[0025] FIG. 3A shows the cutting edge portion 12 having a leading wear surface 12c, which is the surface Aa to be regenerated in a worn state. The outermost two-dot chain line is a virtual reference cutting edge line LN1a in a new, unworn state. The outer shape in a worn state is shown by a solid worn cutting edge line LN1b. The two-dot chain removal cutting edge line LN1c indicates the removal position of the portion to be removed in the next process. The removal cutting edge line LN1c is set as a straight line extending in the front-rear direction above the worn cutting edge line LN1b.

[0026] First, as shown in Fig. 3B, the portion of the worn cutting edge 12 below (toward the tip end) the removal edge line LN1c is removed by grinding or the like. The removal is performed over the entire range in the longitudinal direction (left-right direction) of the punch die 1. As a result, a removal surface 12d, which is a flat surface extending in the front-rear and left-right directions, is formed at the position of the removal edge line LN1c.

[0027] Next, as shown in Fig. 3C, a buildup portion 13 is formed at the tip of the cutting edge 12. The buildup portion 13 completely covers the removal surface 12d, and buildup end positions P2a, P2b, which are the upper ends of the buildup, are located closer to the base side (upper side) of the cutting edge 12 than the removal surface end positions P1a, P1b, which are the connecting positions of the removal surface 12d and the first inclined surface 12a and the second inclined surface 12b. The buildup portion 13 is collectively included in the buildup portion B. In addition, if the visible end of the buildup portion B that is connected to the base material A is defined as end Ba, the buildup end positions P2a, P2b are collectively included in end Ba.

[0028] The method of forming the build-up portion 13 is not limited. For example, methods such as laser cladding, PTA (Plasma Transferred Arc Welding) welding, and thermal spraying can be used. The metal to be built-up is also not limited, and may be a material different from the material of the punch body 11 of the base material A, and may be appropriately selected depending on the application and specifications.

[0029] The removal amount and build-up amount for obtaining the removal surface 12d may be appropriately adjusted and set according to the amount of wear of the cutting edge 12. When the removal amount is large, the removal surface end positions P1a, P1b are positioned higher, so that the build-up end positions P2a, P2b need to be positioned further higher to cover the removal surface 12d, requiring a larger build-up amount.

[0030] Next, the padding portion 13 is cut and shaped by the punch forming grindstone 5 described with reference to Fig. 2 to form the recycled punch top 14 corresponding to the reference cutting edge line LN1a. As described above, the punch forming grindstone 5 has a first peripheral convex portion 51 and a second peripheral convex portion 52. Therefore, a first recess 121 corresponding to the first peripheral convex portion 51 is formed on the first inclined surface 12a of the recycled punch top 14, and a second recess 122 corresponding to the second peripheral convex portion 52 is formed on the second inclined surface 12b.

[0031] 3D, the first recess 121 is formed by removing a range including the build-up end position P2a on the first inclined surface 12a. The second recess 122 is formed by removing a range including the build-up end position P2b on the second inclined surface 12b. The depth Dp1 of the first recess 121 and the second recess 122 is determined in accordance with the tolerance set for the dimension in the thickness direction (front-rear direction) of the punch die 1. For example, if the tolerance of the dimension D1 (see FIG. 2) in the thickness direction is set to "+0 mm to -0.05 mm," the depth Dp1 may be set to a value exceeding 0.05 mm in theory, but may be set to, for example, 0.1 mm, including a certain degree of margin.

[0032] The shapes of the first recess 121 and the second recess 122 are not limited as long as they do not protrude from the first inclined surface 12a and the second inclined surface 12b, respectively. The shapes of the first recess 121 and the second recess 122 may be concave curved surfaces with a curved cross section, or may include a three-dimensional plane with a part of the curved cross section being a straight line. For example, the first recess 121 may be connected so that its upper end and lower end are clearly bent with the first inclined surface 12a. In addition, the first recess 121 may be shaped so that its upper end and lower end are smoothly connected to the first inclined surface 12a by rounding, which is desirable from the viewpoint of reducing the influence on the workpiece W during the coining process. The same applies to the second recess 122.

[0033] In the first embodiment of the method for regenerating a bending die described above, the worn cutting edge shape is regenerated, and a punch die 1 having a regenerated punch top 14 with an unused cutting edge shape is obtained.

[0034] In the above-mentioned regeneration method of the first embodiment, whether or not to remove the tip portion of the cutting edge 12 may be determined depending on the degree of wear. In other words, when regenerating when the degree of wear is small, the regeneration method of the second embodiment described below may be carried out without removing the tip portion.

[0035] Specifically, in a second embodiment of the bending die regeneration method, when the amount of wear is less than a predetermined amount in the cutting edge 12 to be regenerated having the tip wear surface 12c shown in Fig. 3A, a padding portion 13 is formed without removing the tip, as shown in Fig. 3E. The padding portion 13 completely covers the tip wear surface 12c, which is the surface Aa to be regenerated, and padding end positions P2a, P2b, which are the upper ends of the padding portion 13, are located closer to the base side (upper side) of the cutting edge 12 than the removal surface end positions P3a, P3b, which are the connection positions of the tip wear surface 12c and the first and second inclined surfaces 12a and 12b.

[0036] In the second embodiment, the method of forming the build-up portion 13 is not limited. For example, methods such as laser cladding, PTA (Plasma Transferred Arc Welding) welding, and thermal spraying can be used. The metal to be built-up is also not limited, and may be appropriately selected depending on the application and specifications.

[0037] Next, using the punch forming grindstone 5 described with reference to Fig. 2, the padding portion 13 is cut to form a recycled punch top portion 14 corresponding to the reference cutting edge line LN1a, as shown in Fig. 3F. As described above, the punch forming grindstone 5 has a first peripheral convex portion 51 and a second peripheral convex portion 52. Therefore, a first recess 121 corresponding to the first peripheral convex portion 51 is formed on the first inclined surface 12a of the recycled punch top portion 14, and a second recess 122 corresponding to the second peripheral convex portion 52 is formed on the second inclined surface 12b.

[0038] In this second aspect of the bending die regeneration method, the depth Dp1 of the first recess 121 and the second recess can be determined in the same manner as in the first aspect, depending on the tolerance set for the dimension in the thickness direction (front-to-back direction in Figure 3F) of the punch die 1.

[0039] (Die mold 2) Next, a procedure for regenerating the die 2 of the second embodiment of the recycled bending die K of the present invention by the first embodiment of the method for regenerating a bending die of the present invention will be described with reference to Figs. 4 to 5D.

[0040] As shown in FIG. 4, the die 2 has a die body 21 as a substantially plate-shaped base material A extending vertically and horizontally, and a V-groove 22 formed on an upper edge of the die body 21. The die body 21 is attached to a die holder of a bending machine. In the case of a bending machine in which the die side is fixed and the punch side is raised and lowered, the die 2 comes into contact with the underside of a workpiece W (see FIG. 5A) disposed between the punch 1 which rises and lowers above, and the V-groove 22 receives the workpiece pushed down by the descending punch 1, thereby bending the workpiece. In FIG. 5A, the workpiece W is shown at a position spaced above the die 2 for the sake of simplicity.

[0041] 4, the V-groove portion 22 is formed in a V-groove shape having a pair of inclined surfaces tapered downward. The inclined plane on the front side of the V-groove portion 22 is a first groove surface 22a as a first inner surface, and the inclined plane on the rear side is a second groove surface 22b as a second inner surface. In the V-groove portion 22, the first groove surface 22a has a first recess 221 extending in the left-right direction, and the second groove surface 22b has a second recess 222 extending in the left-right direction. The first recess 221 and the second recess 222 are collectively referred to as recess E.

[0042] The first groove surface 22a and the second groove surface 22b are ground by a die forming grindstone 6 (see FIG. 5D) to form a predetermined surface. The die forming grindstone 6 will be described later.

[0043] The V groove portion 22 worn by use can be regenerated by applying a first embodiment of the bending die regeneration method as follows. FIG. 5A shows the V groove portion 22, which is the regeneration target surface Aa in a worn state. The outermost two-dot chain line is the reference groove line LN2a, which indicates the outer shape in an unused state that is not worn. The outer shape in a worn state is indicated by the solid wear groove line LN2b. The two-dot chain removal groove line LN2c indicates the position to be removed in the next process. The pair of front and rear removal groove lines LN2c are set below the wear groove line LN2b as straight lines with an inclination angle close to that of the first groove surface 22a and the second groove surface 22b, respectively.

[0044] 5B, the portion of the V-groove portion 22 in this worn state that is on the tip side (upper side) of the removal groove line LN2c is removed by polishing or the like. The removal is performed over the entire range in the longitudinal direction (left-right direction) of the die 2. As a result, a first removal surface 22ad and a second removal surface 22bd, which are flat surfaces extending in the front-rear and left-right directions at the position of the removal groove line LN2c, are formed in the first groove surface 22a and the second groove surface 22b, respectively.

[0045] Next, as shown in FIG. 5C, padding portions 23 are formed at both front and rear end portions of the V-groove portion 22. The padding portion 23 on the front side is the first padding portion 23a, and the padding portion 23 on the rear side is the second padding portion 23b. The first padding portion 23a on the front side is formed so as to completely cover the first removal surface 22ad. That is, the padding end position P4a, which is the lower end of the padding, is located closer to the back of the V-groove portion 22 than the removal surface end position P3a, which is the connecting position between the removal surface 2ad and the first groove surface 22a. Similarly, the second padding portion 23b on the rear side is formed so as to completely cover the second removal surface 22bd. That is, the padding end position P4b, which is the lower end of the padding, is located closer to the back of the V-groove portion 22 than the removal surface end position P3b, which is the connecting position between the second removal surface 2bd and the second groove surface 22b. The padding portions 23 are collectively referred to as padding portions B. Moreover, the padding end positions P4a and P4b are collectively included in the end Ba.

[0046] The method of depositing the V-groove portion 22 is not limited. For example, methods such as laser cladding, PTA (Plasma Transferred Arc Welding) welding, and thermal spraying can be used. The metal to be deposited is also not limited, and may be a material different from the material of the die body portion 21 of the base material A, and may be appropriately selected depending on the application and specifications.

[0047] The removal amount and build-up amount for obtaining the first removal surface 22ad and the second removal surface 22bd may be appropriately adjusted and set according to the amount of wear of the first groove surface 22a and the second groove surface 22b of the V-groove portion 22. When the removal amount is large, the removal surface end positions P3a, P3b are positioned further downward, and therefore, in order to cover the first removal surface 22ad and the second removal surface 22bd, the build-up end positions P4a, P4b need to be positioned further downward, requiring a larger build-up amount.

[0048] Next, as shown in Fig. 5D, the die forming grindstone 6 cuts and forms the padding portion 23, forming the regenerated die groove portion 24 corresponding to the reference groove line LN2a. As shown in Figs. 5D and 6B, the die forming grindstone 6 is a grindstone having a cylindrical or disk-shaped base body 60, and a predetermined grinding portion 6G is formed on the circumferential surface. The predetermined grinding portion 6G has a shape corresponding to the final finished shape of the V-groove portion 22. The die forming grindstone 6 is collectively referred to as grindstone C, and the grinding portion 6G is collectively referred to as grinding portion Ca.

[0049] The grinding portion 6G has a first convex inclined grindstone surface 6a that forms the first groove surface 22a of the V groove portion 22 and a second convex inclined grindstone surface 6b that forms the second groove surface 22b of the V groove portion 22. The first convex inclined grindstone surface 6a has a first peripheral convex portion 61 that forms the first recessed portion 221 of the V groove portion 22, and the second convex inclined grindstone surface 6b has a second peripheral convex portion 62 that forms the second recessed portion 222 of the V groove portion 22. The first peripheral convex portion 61 and the second peripheral convex portion 62 are convex portions formed over the entire circumference in shapes corresponding to the shapes of the first recessed portion 221 and the second recessed portion 222, respectively. The first peripheral convex portion 61 and the second peripheral convex portion 62 are included in the peripheral convex portion Ca1 as a general term.

[0050] The die forming grindstone 6 is attached to a grinding machine (not shown) and rotates about an axis CL6, and is pressed against the V-groove portion 22. As a result, the V-groove portion 22 is formed by grinding into a shape corresponding to the ground portion 6G.

[0051] By using this die forming grinding wheel 6 to cut and form the V-groove portion 22 having the padding portion 23, a first recess 221 corresponding to the first circumferential convex portion 61 is formed on the first groove surface 22a of the recycling die groove portion 24, and a second recess 222 corresponding to the second circumferential convex portion 62 is formed on the second groove surface 22b.

[0052] 5D, the first recess 221 is formed by removing a range including the build-up end position P4a on the first groove surface 22a. The second recess 222 is formed by removing a range including the build-up end position P4b on the second groove surface 22b. The depth Dp2 of the first recess 221 and the second recess 222 is determined according to the tolerance set for the dimension in the thickness direction (front-rear direction in FIG. 5D) of the die 2. For example, if the tolerance of the dimension D2 (see FIG. 4) in the thickness direction is set to "+0 mm to -0.05 mm," the depth Dp2 may be set to a value exceeding 0.05 mm in theory, but may be set to, for example, 0.1 mm, including a certain degree of margin.

[0053] The shapes of the first recess 221 and the second recess 222 are not limited as long as they do not protrude from the first groove surface 22a and the second groove surface 22b, respectively. The shapes of the first recess 221 and the second recess 222 may be concave curved surfaces with a curved cross section, or may include a three-dimensional plane with a part of the curved cross section being a straight line. For example, the first recess 221 may be connected so that its upper end and lower end are clearly bent with the first groove surface 22a. In addition, the first recess 221 may be shaped so that its upper end and lower end are smoothly connected to the first groove surface 22a by rounding, which is desirable from the viewpoint of reducing the influence on the workpiece W during the coining process. The same applies to the second recess 222.

[0054] As described above, the worn V-groove shape is regenerated by the first embodiment of the bending die regenerating method, and the die 2 having the regenerated die groove portion 24 in an unused state is obtained.

[0055] Whether or not to remove the portion on the tip side of the V-groove portion 22 may be determined depending on the degree of wear. That is, when regenerating when the degree of wear is small, the portion on the tip side is not removed, the padding portion 23 is formed, and the V-groove portion 22 is ground with the die forming grindstone 6 to form it into the standard groove shape, in accordance with the second embodiment of the method for regenerating a bending die described above.

[0056] According to the first and second aspects of the bending die recycling method described above in detail, the range including the end of the build-up portion 13, 23 is carved out to form the first recesses 121, 221 and the second recesses 122, 222, so that no step is formed at the end. Therefore, the recycled bending die K has high appearance quality, and when the bending is so-called coining, there is no risk of a line corresponding to the step being formed on the workpiece W, and the bent workpiece W has high appearance quality.

[0057] Each aspect of the present invention is not limited to the above-described configurations and procedures, and may be modified without departing from the spirit and scope of the present invention.

[0058] The first recesses 121, 221 and the second recesses 122, 222 need only be formed by carving out the portions that will become the ends of the padding portions 13, 23, respectively, and the depth, formation range, cross-sectional shape, etc. of the carved out portions can be freely set according to the range of the worn portion and the degree of wear.

[0059] The punch body 11 and the die body 21, which are the base material A, are formed of a first metal material, and the padding portions 13, 23, which are the padding portion B, are formed of a second metal material. The first and second materials do not have to be the same, and the second material that comes into contact with the workpiece W may be a metal material different from the first material that has better wear resistance or chipping resistance.

[0060] The regeneration of bending dies having worn portions has been described above, but the regeneration in the present invention is not limited to regeneration from wear, but also includes repair of portions damaged by corrosion, overload, etc.

[0061] As described in detail above, one embodiment of the bending die regeneration method of the present invention includes a build-up process for forming a build-up portion B covering the entirety of the regeneration target surface Aa on a base material A of a regeneration bending die K having a regeneration target surface Aa of a shape different from a reference shape, and a shaping process for rotating a grinding wheel C having a grinding portion Ca for grinding the build-up portion B to shape the build-up portion B into the reference shape and regenerate it, wherein the grinding portion Ca of the grinding wheel C has a peripheral convex portion Ca1 that is carved out to include the external end portion Ba of the build-up portion B that connects to the base material A, and the shaping process forms a recess E in the regeneration bending die K by the peripheral convex portion Ca1, which includes the external boundary between the base material A and the build-up portion B.

[0062] As a result, a recess E including the boundary between the base material A and the build-up portion B is formed, and no steep step is formed where the build-up portion B becomes convex from the surface of the recycled bending die K. Therefore, the recycled bending die K has high appearance quality, and even if the recycled bending process is coining, no line corresponding to the step is formed on the surface of the workpiece W, and the appearance quality is not reduced.

[0063] Also, in this embodiment, the recycled bending die K is a punch die 1, and the cutting edge portion of the punch die 1 has a first outer surface 12a and a second outer surface 12b that approach each other toward the tip, and the recess E may be simultaneously formed as a first recess 121 on the first outer surface 12a and a second recess 122 on the second outer surface 12b.

[0064] This reduces the time required to remanufacture the punch die 1, which is the remanufactured bending die K.

[0065] Also, in this embodiment, the recycled bending mold K is a die mold 2 having a V-groove portion 22, and the V-groove portion 22 has a first inner surface 22a and a second inner surface 22b that approach each other toward the back, and the recess E may be simultaneously formed as a first recess 221 on the first inner surface 22a and a second recess 222 on the second inner surface 22b.

[0066] This shortens the time required to regenerate the die 2, which is the regenerated bending tool K.

[0067] In this embodiment, the build-up portion B may be formed by stacking metal powder.

[0068] This allows thin build-up and precise control of build-up thickness. In addition, the welded surface, which is the layered surface, becomes smooth.

[0069] One embodiment of the recycled bending die of the present invention is a recycled bending die comprising a first portion MA which is approximately plate-shaped and formed from a first material, and which has at one edge a cutting edge portion 12 or a V-groove portion 22 whose cross-sectional shape is V-shaped composed of a first surface and a second surface, and a second portion MB which is provided on the tip side of the cutting edge portion 12 or V-groove portion 22 and which is formed from a second material different from the first material, and the first surface and the second surface each have a recess E formed in a range that includes the apparent boundary between the first portion MA and the second portion MB.

[0070] As a result, when the first region MA is the base material A and the second region MB is the built-up portion B, a recess E including the boundary between them is formed, and therefore no steep step is formed where the built-up portion B becomes convex from the surface of the recycled bending die K. Therefore, the appearance quality of the recycled bending die K is not degraded, and even if the bending process is coining, no line corresponding to the step is formed on the surface of the workpiece W, and the appearance quality is not degraded.

[0071] This aspect may also be a punch die 1 having a cutting edge portion 12 at the first region MA.

[0072] As a result, no steep step is formed on the surface of the recycled punch die 1 due to the protruding padding portion B, and the recycled punch die 1 does not leave lines on the surface of the workpiece W due to the padding portion B, so the appearance quality of the workpiece W is not reduced.

[0073] Also, this embodiment may be a die 2 having a V-groove portion 22 in the first portion MA.

[0074] As a result, no steep steps are formed on the surface of the recycled die 2 due to the protruding build-up portion B, and the recycled die 2 does not leave lines on the surface of the workpiece W due to the build-up portion B, so the appearance quality of the workpiece W is not reduced. [Explanation of symbols]

[0075] 1 Punch die 11 Punch body 12 Cutting edge 12a 1st inclined surface (1st outer surface) 12b Second inclined surface (second outer surface) 12c Tip wear surface (surface to be regenerated) 12d removed surface 121 First recess 122 Second recess 13 Meat platter 14 Recycled punch top 2 Die mould 21 Die body 22 V groove 22a 1st groove surface 22ad 1st removal surface 22b 2nd groove surface 22bd 2nd removal surface 221 First recess 222 Second recess 23 Meat platter 23a First meat section 23b 2nd meat section 24 Recycled die groove 5 Punch forming grinding wheel 5a First concave inclined grinding wheel surface 5b Second concave inclined grinding wheel surface 5G Grinding section 50 Substrate 51 1st circumference convex part 52 2nd peripheral convex part 6 Die-formed grinding wheels 6a First convex inclined grinding wheel surface 6b Second convex inclined grinding wheel surface 6G Grinding section 60 Substrate 61 1st circumference convex part 62 2nd peripheral convex part A Base material Aa Regeneration target surface B Meat serving section C. Grindstone Ca grinding part E recess CL5,CL6 axis line Dp1,Dp2 depth D1,D2 dimensions K Recycled bending mold MA 1st part MB Part 2 LN1a Reference cutting edge line LN1b Wear edge line LN1c Removal cutting edge LN2a Reference groove line LN2b wear grooves LN2c removed channel wire P1a,P1b,P3a,P3b Edge position of removal surface P2a, P2b, P4a, P4b Filling end position W work

Claims

1. a padding process for forming a padding portion covering the entire surface to be regenerated on a base material of a bending die having a surface to be regenerated that is different from a reference shape; a forming step of rotating a grindstone having a grinding portion for grinding the padding portion to form the padding portion into a reference shape and regenerating the padding portion; Including, The grinding portion of the grindstone has a peripheral convex portion that is carved out to include an external end portion of the padding portion that is connected to the base material, The molding step is a method for recycling a bending die, in which a recess is formed in the bending die by the peripheral convex portion, the recess including the appearance boundary between the base material and the build-up portion.

2. The bending die is a punch die, and a cutting edge portion of the punch die has a first outer surface and a second outer surface which approach each other toward a tip end, The method for regenerating a bending die according to claim 1 , wherein the recesses are simultaneously formed as a first recess in the first outer surface and a second recess in the second outer surface.

3. The bending tool is a die having a V-groove, the V-groove having a first inner surface and a second inner surface which approach each other toward the back, The method for regenerating a bending die according to claim 1 , wherein the recesses are simultaneously formed as a first recess on the first inner surface and a second recess on the second inner surface.

4. The method for regenerating a bending die according to any one of claims 1 to 3, wherein the build-up portion is formed by stacking metal powder.

5. a first portion having a substantially plate-like shape formed from a first material and having a cutting edge portion or a V-groove portion having a V-shaped cross section formed by a first surface and a second surface at one edge; A second portion is provided on a tip side of the cutting edge portion or the V-groove portion and is made of a second material different from the first material, the first surface and the second surface each have a recess formed in a range including an apparent boundary between the first region and the second region, A recycled bending die which is a punch die having the cutting edge portion at the first portion.

6. a first portion having a substantially plate-like shape formed from a first material and having a cutting edge portion or a V-groove portion having a V-shaped cross section formed by a first surface and a second surface at one edge; A second portion is provided on a tip side of the cutting edge portion or the V-groove portion and is made of a second material different from the first material, the first surface and the second surface each have a recess formed in a range including an apparent boundary between the first region and the second region, The first portion and the second portion are smoothly connected to each other by rounding. the second portion is formed of laminated metal powder; A recycled bending mold which is a die having the V-groove portion in the first portion.

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