JP2007136463A - Die for press brake and method for manufacturing it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a die for press brakes which can be held accurately and stably with a clamping device, and also to provide a method of manufacturing it. <P>SOLUTION: For example, a punch 6 is provided with an engaging groove 23A which is engaged with a projection 15a provided on a movable clamping member 15 of the clamping device 9, wherein the engaging groove 23A is formed into a V-shape having a first slope 25A and a second reference surface 26A which are formed into facial symmetry each other about the center surface 24. When finishing this engaging groove 23A, grinding is performed by using a form grinding wheel 32 formed into a shape conforming to the engaging groove 23A. The shape measurement of the groove to which this grinding work is applied should be performed by a measuring method using an over pin 37. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a press brake mold that is mounted on a press brake via a clamp device and performs bending of a plate material, and a manufacturing method thereof.

  Conventionally, for example, a clamp device for holding a punch in a press brake mold sandwiches the punch between a rear fixed plate and a front movable plate at the lower part of the ram, and tightens the movable plate with a bolt. To be clamped. For this reason, when replacing the punch, many bolts must be tightened or loosened with a tool, which is very laborious and time-consuming, and if the bolts are inadvertently loosened, the punch may fall off. There is. For this reason, for example, Patent Document 1 proposes a clamping device that can easily attach and detach the punch and prevent the punch from dropping.

US Pat. No. 6,446,485

  As shown in FIG. 10A, the clamp device 100 according to Patent Document 1 includes a clamp device body 103 fixed by a fixing member 102 attached to a lower portion of a ram 101 in a press brake, and the clamp device. A fixed clamp member 104 provided integrally with the clamp device main body 103 on the rear side (left side in the drawing) of the main body 103 and the front side (right side in the drawing) of the clamp device main body 103 to form a pair with the fixed clamp member 104. And a movable clamp member 106 attached to the clamp device main body 103 via a pivot shaft 105, and an upper end portion of a punch 107 brought between the fixed clamp member 104 and the movable clamp member 106. The clamp members 104 and 106 can be sandwiched. Here, a protrusion 106 a that protrudes inward is provided at the tip of the movable clamp member 106, while an engagement groove 108 that can be engaged with the protrusion 106 a is provided at the upper end of the punch 107. Is provided. As shown in FIG. 10 (d), the engaging groove 108 includes a bevel groove portion 108a having an inclined surface 109 that contacts the protrusion 106a, and a relief groove portion formed as a relief portion of a tool during machining. The bevel groove portion 108a and the relief groove portion 108b are asymmetrical with respect to the flat surface 110 that is formed by 108b and is parallel to the upper end surface of the punch 107 and located in the middle of the engagement groove 108.

  In the clamp device 100, 1) a clamp state in which the upper end portion of the punch 107 is firmly sandwiched between the fixed clamp member 104 and the movable clamp member 106 to fix the punch 107 (see FIG. 10A), and 2) the above The protrusions 106a are inserted into the engaging grooves 108 to prevent the punch 107 from falling, and the upper end portions of the punch 107 are clamped to such an extent that the punch 107 can be moved in the left-right direction (direction perpendicular to the paper surface of FIG. 10). (3) Unclamped state in which the movable clamp member 106 is expanded so that the punch 107 is completely free from the clamp members 104 and 106 (see FIG. 10B). There are three states as shown in FIG. Then, the clamped state shown in FIG. 10A and the half-clamped state shown in FIG. 10B are switched by a predetermined turning operation of a lever (not shown) attached to the clamp device main body 103. Further, in the unclamped state shown in FIG. 10C, when the lower part of the movable clamp member 106 is pushed with a finger or the like, the half-clamped state shown in FIG. Further, in the half clamp state shown in FIG. 10B, when the upper part of the movable clamp member 106 is pushed with a finger or the like, the unclamped state shown in FIG.

  Here, when shifting from the half clamp state shown in FIG. 10B to the clamp state shown in FIG. 10A, the inclined surface 109 of the engagement groove 108 is pushed by the protrusion 106a of the movable clamp member 106. Therefore, the entire punch is pushed up while the rear surface (the left surface in the figure) of the upper end of the punch is pressed against the fixed clamp member 104. When the transition to the clamped state is completed, the rear surface of the punch upper end is pressed against the fixed clamp member 104 and the punch upper end surface is pressed against the clamp device main body 103, whereby the punch 107 is moved to the clamp device 100. Positioning is performed, and the posture of the punch 107 with respect to the clamping device 100 is maintained. Therefore, in order to stably hold the posture of the punch 107 with respect to the clamp device 100 with high accuracy, it is necessary to finish the inclined surface 109 of the engagement groove 108 with high accuracy.

  However, in the conventional punch 107, since the engagement groove 108 is not formed in consideration of the ease of shape measurement, the shape accuracy of the inclined surface 109 of the engagement groove 108 is determined. It is extremely difficult to judge. Therefore, since the inclined surface 109 of the engaging groove 108 cannot be finished with high accuracy, the posture of the punch 107 becomes unstable with respect to the clamping device 100, and there is a problem that high-precision bending cannot be performed. . Further, when an upper die is constructed by combining a plurality of punches, the cutting edges of those punches are not aligned, so that there is a problem that the bent product is damaged. It goes without saying that the same problem occurs when the clamping device 100 holds the die in the press brake mold.

  The present invention has been made to solve such problems, and an object of the present invention is to provide a press brake die that can be accurately and stably held in a clamp device and a method for manufacturing the same. It is.

In order to achieve the above object, a press brake mold according to the first aspect of the present invention is provided.
Attached to a clamp device comprising a clamp device body fixed to a press brake ram, a fixed clamp member provided integrally with the clamp device body, and a movable clamp member paired with the fixed clamp member A press brake mold for bending a plate material,
(A) When clamped by the fixed clamp member and the movable clamp member, a first reference surface that is in contact with the fixed clamp member, and a contact with the clamp device body that is orthogonal to the first reference surface A proximal end having a second reference surface to be
(B) a tip portion having a functional portion that substantially contributes to bending of the plate material; and (c) a protrusion provided on the movable clamp member when clamped by the fixed clamp member and the movable clamp member. An engagement groove for engagement;
The engaging groove has a plane that is parallel to the second reference plane and that is separated from the second reference plane by a predetermined distance in the direction from the second reference plane toward the tip portion, and the center plane and the second reference plane. A first inclined surface that is disposed between the first inclined surface and abuts against the protrusion, and has a second inclined surface that is symmetrical with the first inclined surface with respect to the center surface. The distance is such that the distance increases toward the opening side of the engagement groove.

  In the first invention, it is preferable that a hard film by electric discharge machining is formed on the first inclined surface (second invention).

Next, a method for manufacturing a press brake mold according to the third invention is as follows.
A method for manufacturing a press brake mold according to a first invention,
(A) Roughing process of forming a groove smaller than the engaging groove at a site where the engaging groove is to be formed by cutting,
(B) A grinding process for grinding the groove formed in the roughing process using a general grinding wheel formed into a shape matching the engagement groove; and (c) the grinding process. A groove shape measuring step of pressing an overpin as a measuring element against the groove to which the overpin is applied and measuring a distance between the overpin and the first reference surface and a distance between the overpin and the second reference surface. It is characterized by including.

  3rd invention WHEREIN: The surface hardening process which forms a hard film by electric discharge machining with respect to at least the said 1st inclined surface in the said engagement groove determined from the measurement result by the said groove shape measurement process to satisfy | fill predetermined | prescribed shape precision It is preferable to include a surface hardening treatment step for applying (fourth invention).

  In the press brake mold according to the present invention, when clamped by the fixed clamp member and the movable clamp member, the first reference surface that is in contact with the fixed clamp member and the clamp orthogonal to the first reference surface A second reference surface that comes into contact with the apparatus main body is provided, and an engagement groove that engages with a protrusion provided on the movable clamp member is provided. The engaging groove has a plane that is parallel to the second reference plane and that is separated from the second reference plane by a predetermined distance in the direction from the second reference plane toward the die tip. A first inclined surface disposed between the reference surface and abutting the protrusion; and a second inclined surface that is symmetrical with the first inclined surface with respect to the central surface. The interval is increased to the opening side of the engagement groove. When an overpin as a measuring element is pressed against the engaging groove having such a shape, that is, when the peripheral surface of the overpin is brought into contact with each of the first inclined surface and the second inclined surface, the center surface of the engaging groove There will be an overpin axis centerline above. By measuring the distance between the overpin and the first reference surface and the distance between the overpin and the second reference surface, it is possible to easily and accurately determine the shape accuracy of the engagement groove. In particular, it is possible to easily and accurately determine the accuracy of the shape of the first inclined surface, which is important for holding the clamp device accurately and stably. For this reason, since it becomes possible to finish the 1st inclined surface in an engaging groove with high precision, there exists an effect that it is hold | maintained to a clamp apparatus accurately and stably. Therefore, it is possible to perform high-precision bending, and even when a plurality of punches are combined to construct an upper mold, the cutting edges of those punches are aligned, so that the bent product is not damaged. Absent.

  Here, the press brake mold according to the present invention is formed by a roughing process in which a groove smaller than the engagement groove is formed by cutting at a portion where the engagement groove is to be formed, and the roughing process. A grinding process in which a grinding process is performed using a general grinding wheel formed into a shape that matches the engagement groove, and an overpin as a probe for the groove subjected to the grinding process. And a groove shape measuring step for measuring the distance between the overpin and the first reference surface and the distance between the overpin and the second reference surface, respectively. Therefore, it is possible to provide a press brake mold having an engagement groove finished with high accuracy.

  In addition, the structure which forms a hard film in the 1st inclined surface by performing the surface hardening process which forms a hard film by electrical discharge machining with respect to at least the 1st inclined surface in the said engagement groove | channel is employ | adopted. Thus, it is possible to reliably suppress the engagement groove from being deformed with the repetition of the clamping / unclamping operation of the clamping device, in particular, the wear of the first inclined surface.

  Next, specific embodiments of a press brake mold and a manufacturing method thereof according to the present invention will be described with reference to the drawings.

  FIG. 1 is a front view showing a main part in a state where a press brake mold according to an embodiment of the present invention is mounted on a press brake. FIG. 2 is a view taken in the direction of arrow A in FIG. This embodiment is an example in which the present invention is applied to a punch in a press brake mold.

  In the press brake 1 shown in FIG. 1, an upper mold 4 and a lower mold 5 are disposed between a ram 2 and a table 3 so as to face each other, and the upper mold 4 and the lower mold 5 cooperate with each other. A V-bending process can be performed on a work material (for example, a steel plate, an aluminum alloy plate, etc.) disposed between the mold 4 and the lower mold 5. The upper die 4 is constructed by combining a plurality of (three in the present embodiment) punches 6, 7, and 8, and these punches 6, 7, and 8 are arranged above the clamping device 9 and the fixing member 10. It is attached to the ram 2. On the other hand, a die (hereinafter referred to as “die 5”) as the lower mold 5 has a V-shaped groove 5a (as a functional portion that substantially contributes to V-bending processing at the tip (upper end) thereof. Hereinafter, it is simply formed as “V-groove 5 a”, and is mounted on the lower table 3 through the die holder 11.

  As shown in FIG. 2, the clamp device 9 includes a clamp device body 12 fixed by the fixing member 10 attached to the lower portion of the ram 2, and a rear side (left side in the drawing) of the clamp device body 12. The clamp device 13 is provided integrally with the clamp device main body 12, and is disposed on the front side (right side in the figure) of the clamp device body 12 so as to form a pair with the fixed clamp member 13. And a movable clamp member 15 attached to the clamp device main body 12, and the upper ends of the punches 6, 7, 8 brought between the fixed clamp member 13 and the movable clamp member 15 are connected to the clamp members 13, 15. It is comprised so that it can be pinched by. Here, a protrusion 15 a that protrudes inward is provided at the tip of the movable clamp member 15.

  In this clamping device 9, 1) a clamped state in which the upper ends of the punches 6, 7, 8 are firmly sandwiched between the fixed clamping member 13 and the movable clamping member 15 to fix the punches 6, 7, 8 (FIG. 3A )) And 2) the protrusion 15a is inserted into an engaging groove 23A described later to prevent the punches 6, 7, and 8 from falling, and the left and right directions of the punches 6, 7, and 8 (the direction perpendicular to the drawing sheet). ) In a half-clamped state in which the upper ends of the punches 6, 7, 8 are sandwiched between the clamp members 13, 15 (see FIG. 3B), and 3) with respect to the clamp members 13, 15. There are three states in an unclamped state (see FIG. 3C) in which the movable clamp member 15 is expanded so that the punches 6, 7, and 8 are completely free. Then, the clamped state shown in FIG. 3A and the half-clamped state shown in FIG. 3B are switched by a predetermined turning operation of a lever (not shown) attached to the clamp device body 12. Further, in the unclamped state shown in FIG. 3C, when the lower part of the movable clamp member 15 is pushed with a finger or the like, the half-clamped state shown in FIG. Further, in the half clamp state shown in FIG. 3B, when the upper portion of the movable clamp member 15 is pushed by a finger or the like, the unclamped state shown in FIG.

  Here, when shifting from the half-clamped state shown in FIG. 3B to the clamped state shown in FIG. 3A, the first described later in the engaging groove 23 </ b> A by the protrusion 15 a of the movable clamp member 15. Since the inclined surface 25A (see FIG. 4) is pushed, the entire punch is pushed up while the rear surface of the upper end of the punch (the left surface in the figure: a first reference surface 20B described later) is pressed against the fixed clamp member 13. When the transition to the clamp state is completed, the rear surface of the punch upper end is pressed against the fixed clamp member 13 and the punch upper end surface (second reference surface 21 described later) is pressed against the clamp device body 12, respectively. As a result, the punches 6, 7 and 8 are positioned on the clamping device 9, and the postures of the punches 6, 7 and 8 with respect to the clamping device 9 are maintained.

  The plurality of punches 6, 7, 8 constituting the upper mold 4 have the same basic shape (side view shape) only in the width dimension in the left-right direction (see FIG. 1). In the upper die 4, the widest punch 6 is disposed on the left side, and the punch 8 having a width slightly narrower than that of the left punch 6 is disposed on the right side. A punch 7 is arranged. In the following, the leftmost punch 6 with the widest width will be mainly described, and the other punches 7 and 8 will be described with reference to the punch 6.

  As shown in FIG. 2, when the punch 6 is clamped by the fixed clamp member 13 and the movable clamp member 15, the upper end portion (base end portion) of the punch 6 comes into contact with the fixed clamp member 13. A first reference surface 20B and a second reference surface 21 that is orthogonal to the first reference surface 20B and is in contact with the clamp device body 12 are provided. Moreover, the lower end part (tip part) is provided with a blade part (functional part) 22 that substantially contributes to the bending of the plate material. Further, the punch 6 is provided with an engaging groove 23 </ b> A that engages with the protrusion 15 a of the movable clamp member 15 when being clamped by the fixed clamp member 13 and the movable clamp member 15.

  As shown in FIG. 4A, the engagement groove 23A is parallel to the second reference surface 21 and separated by a predetermined distance T in the direction from the second reference surface 21 toward the lower end of the punch. A first inclined surface 25A that is disposed between the center surface 24 and the second reference surface 21 and abuts against the protrusion 15a is defined by using the flat surface 24 as a center surface (hereinafter referred to as “center surface 24”). And has a second inclined surface 26A that is symmetrical with the first inclined surface 25A with respect to the central surface 24, and the interval between the inclined surfaces 25A, 26A advances toward the opening side of the engaging groove 23A. It is formed in a V-shape that becomes larger.

  In the present embodiment, the punch 6 has a groove 23B having the same shape as the engagement groove 23A (hereinafter referred to as “engagement groove 23B”) with the center line 27 passing through the blade edge of the punch 6 as a reference. The engaging groove 23A is provided so as to have a symmetrical position. In this way, the front side surface (right side surface in FIG. 4A) and the back side surface (left side surface in FIG. 4A) of the punch 6 are related to each other with respect to the center line 27 passing through the blade edge of the punch 6. By providing the mating groove 23A and the engaging groove 23B, when the punch 6 is mounted on the clamp device 9, the cutting edge of the punch 6 is die-cut regardless of whether the front or back surface of the punch 6 is disposed on the front side of the press brake 1. In accordance with the center position of the V-groove 5a in FIG. When the back side surface of the punch 6 is disposed on the front side of the press brake 1, the surface 20 </ b> A opposite to the first reference surface 20 </ b> B serves as a reference surface that comes into contact with the fixed clamp member 13.

In the engagement groove 23A, as shown in FIG. 4B, the hard coating 28 is formed by surface hardening treatment by electric discharge machining over the entire surfaces of the first inclined surface 25A and the second inclined surface 26A. It is a membrane. Similarly, in the engagement groove 23B, a hard film 28 is formed over the entire surfaces of the first inclined surface 25B and the second inclined surface 26B by surface hardening treatment by electric discharge machining (not shown). ). According to such surface hardening treatment by electric discharge machining, processing at normal temperature is possible, so that distortion due to the surface hardening treatment does not occur. Therefore, in surface hardening treatments such as heat treatment methods (high-frequency hardening, flame hardening, etc.), nitriding treatment methods, chemical vapor deposition methods (CVD methods), physical vapor deposition methods (PVD methods) A finishing process for finishing the dimensional accuracy and the like to the required quality is required. However, such a distortion correcting process and a finishing process are unnecessary, and both the manufacturing period can be shortened and the manufacturing cost can be reduced. The hard film 28 is a very thin film composed of a hardened surface layer having a thickness of about 0.01 mm and a permeation layer having a thickness of about 0.005 mm. Therefore, the posture when the punch 6 is held by the clamping device 9 is used. Is hardly affected. Moreover, the hard film 28, the a is Vickers hardness _H V of about 2500 to 3000 hardness are those extremely excellent wear resistance. In this way, as the clamping and unclamping operations of the clamping device 9 are repeated, the engagement grooves 23A and 23B are prevented from being deformed, and in particular, the first inclined surfaces 25A and 25B can be reliably prevented from being worn. it can. Since only the first inclined surfaces 25A and 25B are in contact with the protrusions 15a of the movable clamp member 15, a hard film by electric discharge machining is formed only on the first inclined surfaces 25A and 25B. May be.

  Next, the manufacturing method of the punch 6 will be described below with reference to FIGS. In the manufacturing method described below, since the manufacturing process related to the engagement groove 23A and the manufacturing process related to the engagement groove 23B are the same, the manufacturing process related to the engagement groove 23B will be described. It is assumed that the manufacturing process related to the engaging groove 23A has been described with the description of the manufacturing process related to the engaging groove 23B.

  First, a punch 6 'whose outer shape obtained by subjecting a die material (drawing material such as S43C, SCM440H, etc.) to a tempering process, a cutting process, a heat treatment process, a distortion correction process, etc., is almost a finished product. Prepare. In this punch 6 ', the blade surface of the blade portion 22, the first reference surfaces 20A and 20B, and the second reference surface 21 are all finished with a predetermined shape accuracy with a center line 27 passing through the blade edge as a reference. ing.

(Roughing process: see Fig. 5)
Next, the punch 6 ′ is set on the processing stage 30 of the cutting machine through the jig 29. Then, the cutting blade 31 in the cutting machine is rotated, and the cutting blade 31 performs cutting on the portion where the engagement groove 23B is to be formed with reference to the center surface 24, and is slightly smaller than the engagement groove 23B. A groove 23B 'indicated by the middle dotted line is formed in the punch 6'. Here, the jig 29 holds the punch 6 'while holding the blade surface of the blade portion 22, the first reference surface 20A and the second reference surface 21 of the punch 6', thereby sandwiching the punch 6 '. Can be held in a state where positioning has been achieved.

(Grinding process: see Fig. 6)
Next, the grinding wheel 32 is attached to the grinding wheel shaft (not shown) of the grinding machine, and the punch 6 ′ that has undergone the roughing process is set on the machining stage 34 of the grinding machine via the jig 33. Here, the overall grinding grinding wheel 32 is formed by bonding abrasive grains with a binder, and is formed at a grinding wheel main body portion 32a and an intermediate position in the axial direction of the grinding wheel main body portion 32a. The ring-shaped protrusion 32b having a cross-sectional shape that matches the engagement groove 23B. The jig 33 basically has the same structure as the jig 29 described above, and includes the blade surface of the blade portion 22, the first reference surface 20A, and the second reference surface 21 of the punch 6 '. By sandwiching the punch 6 'while holding each surface, the punch 6' can be held in a positioned state. Reference numeral 35 indicates a height-adjustable support that temporarily receives the punch 6 '.

  Then, the ring-shaped protrusion 32b of the total grinding wheel 32 is pressed against the groove 23B ′ formed in the roughing process with the center surface 24 as a reference to perform grinding. In the grinding process using the overall grinding wheel 32 that matches the engaging groove 23B having a symmetrical shape with respect to the center plane 24, the left and right sides in FIG. Since a reaction force that cancels out the deflection of the direction acts, such grinding can be performed stably.

  Here, in the grinding step, as the use of the general grinding wheel 32 progresses, the general grinding wheel 32 is worn, or the eyes are clogged or clogged and the sharpness of the abrasive grains becomes dull. The dresser 36 as shown in FIG. 7 is used to perform dressing for scraping the surface of the grinding wheel 32 so that new abrasive grains appear.

(Groove shape measurement process: see FIG. 8)
Next, an overpin 37 as a measuring element is pressed against the groove 23B ′ subjected to the grinding, and the distance between the overpin 37 and the first reference surface 20A (the dimension indicated by the symbol H in FIG. 8). ) And the distance between the overpin 37 and the second reference surface 21 (the dimension indicated by the symbol L in FIG. 8). In this groove shape measuring step, when the overpin 37 is pressed against the groove 23B ′ subjected to the grinding, that is, the overpin 37 is applied to each of the first inclined surface 25B ′ and the second inclined surface 26B ′. When the peripheral surface is brought into contact, the axial center line of the overpin 37 exists on the central surface 24 of the groove 23B ′. Therefore, the distance H between the overpin 37 and the first reference surface 20A and By measuring the distance L between the overpin 37 and the second reference surface 21, it is possible to easily and accurately determine whether or not the groove 23B 'satisfies a predetermined shape accuracy. Here, as the predetermined shape accuracy, for example, the H dimension and the L dimension are each a reference dimension ± 0.02 mm, and more preferably a reference dimension ± 0.01 mm. In this way, the first inclined surface 25B ′, which is particularly important for holding the clamping device 9 accurately and stably, is finished with high accuracy.

  If it is determined from the measurement result of the groove shape measurement step that the predetermined shape accuracy is satisfied, the process proceeds to the next surface hardening process, and the predetermined shape accuracy is not yet satisfied from the measurement result of the groove shape measurement step. If it is determined, the grinding amount is calculated according to the difference between the current shape dimension and the target shape dimension, and the grinding process is further performed by the amount.

(Surface curing treatment process: see FIG. 9)
A punch 6 'determined to satisfy a predetermined shape accuracy from the measurement result of the groove shape measuring step is placed in a working liquid tank 38 in a discharge surface hardening processing apparatus, and an electrode 39 made of titanium is used as a constituent element of carbon. The titanium ions discharged from the electrode 39 by discharge and the carbon in the machining liquid 40 decomposed by the discharge heat are chemically reacted to form titanium carbide (TiC), and punch 6 The TiC hard film (hard ceramic film) is formed on the surface of the groove 23B 'in FIG.

  Through the steps described above, the punch 6 having the engagement grooves 23A and 23B having high accuracy and excellent wear resistance can be obtained. Similarly, the punch 6 having high accuracy and wear resistance is excellent. Punches 7 and 8 having engagement grooves 23A and 23B can be obtained.

  According to the punches 6, 7, and 8 of the present embodiment, the first inclined surfaces 25 </ b> A and 25 </ b> B in the engagement grooves 23 </ b> A and 23 </ b> B are finished with high accuracy, so that the clamp device 9 can be stably and accurately held. There is an effect. Therefore, high-precision bending can be performed, and since the cutting edges of the punches 6, 7, and 8 are aligned, the bent product is not damaged.

  In this embodiment, an example in which the present invention is applied to a punch in a press brake mold is shown. However, according to the gist of the present invention, the present invention is applied to a die in a press brake mold. Is also possible.

The front view showing the principal part of the state with which the metal mold | die for press brakes concerning one Embodiment of this invention was mounted | worn with the press brake. 1 arrow view of FIG. The state explanatory drawing of a clamp apparatus, The figure (a) showing a clamp state, The figure (b) showing a half clamp state, and the figure (c) showing an unclamp state Punch structure explanatory drawing (a) and B part enlarged view of (a) (b) Illustration of roughing process Illustration of grinding process Illustration of dressing Explanation of groove shape measurement process Explanatory drawing of surface hardening treatment process Illustration of prior art

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Press brake 2 Ram 6, 7, 8 Punch 9 Clamp apparatus 12 Clamp apparatus main body 13 Fixed clamp member 15 Movable clamp member 15a Protrusion 20A, 20B 1st reference surface 21 2nd reference surface 22 Blade part 23A, 23B Engagement Groove 24 Center surface 25A, 25B First inclined surface 26A, 26B Second inclined surface 28 Hard coating 32 Total grinding wheel 37 Overpin

Claims (4)

Attached to a clamp device comprising a clamp device body fixed to a press brake ram, a fixed clamp member provided integrally with the clamp device body, and a movable clamp member paired with the fixed clamp member A press brake mold for bending a plate material,
(A) When clamped by the fixed clamp member and the movable clamp member, a first reference surface that is in contact with the fixed clamp member, and a contact with the clamp device body that is orthogonal to the first reference surface A proximal end having a second reference surface to be
(B) a tip portion having a functional portion that substantially contributes to bending of the plate material; and (c) a protrusion provided on the movable clamp member when clamped by the fixed clamp member and the movable clamp member. An engagement groove for engagement;
The engaging groove has a plane that is parallel to the second reference plane and that is separated from the second reference plane by a predetermined distance in the direction from the second reference plane toward the tip, and the center plane and the second reference plane. A first inclined surface that is disposed between the first inclined surface and abuts against the protrusion, and has a second inclined surface that is symmetrical with the first inclined surface with respect to the center surface. A press brake mold characterized by having a shape in which the distance increases as it advances toward the opening side of the engagement groove.   The press brake mold according to claim 1, wherein a hard film by electric discharge machining is formed on the first inclined surface. It is a manufacturing method of the metal mold for press brakes according to claim 1,
(A) Roughing process of forming a groove smaller than the engaging groove at a site where the engaging groove is to be formed by cutting,
(B) A grinding process for grinding the groove formed in the roughing process using a general grinding wheel formed into a shape matching the engagement groove; and (c) the grinding process. A groove shape measuring step of pressing an overpin as a measuring element against the groove to which the overpin is applied and measuring a distance between the overpin and the first reference surface and a distance between the overpin and the second reference surface. The manufacturing method of the metal mold | die for press brakes characterized by including these.   Surface hardening treatment for applying a surface hardening treatment for forming a hard film by electric discharge machining on at least the first inclined surface of the engagement groove determined to satisfy a predetermined shape accuracy from the measurement result of the groove shape measurement step The manufacturing method of the metal mold | die for press brakes of Claim 3 in which a process is included.

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