JP2011235320A - Punching die, and method for grinding the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a punching die in which biting of a punched piece to an inner wall of a side pressure providing part in a through-hole of a die can be well kept in a punching processing repeated for a long time, and to provide a method for grinding the same.SOLUTION: The punching die includes the die formed of a pair of halved parts having the through-hole prepared with the side pressure giving part and a tapered hole. In the paired respective halved parts, the inner walls 3b of parts to be the side pressure giving parts 3 are made to be finishing grinding surfaces on which only grinding traces 44 are formed.

Description

  The present invention relates to a punching die in which a metal plate is punched by a punch and a die, and in particular, the wear resistance of the inner wall of the through hole formed in the die is improved and the opening edge of the through hole is chipped. It is related to a difficult punching die.

  Conventionally, a punching die composed of a punch and a die is used to make a hole in a thin metal plate. For example, as shown in FIG. 7, an oval hole 31 is punched into the metal plate 30 by a punching die. At the time of this punching, as shown in FIG. 8, the metal plate 30 is placed on the workpiece placement surface 34 a of the die 34 fixed to the die holder 35. The metal plate 30 is pressed and fixed by the stripper 36 and the oblong hole 31 is punched by the punch 33. The through hole 38 formed in the die 34 includes an upper side pressure applying portion 39 and a lower tapered hole portion 40. The extracted pieces 32 are accumulated in the lateral pressure applying unit 39. When a predetermined number or more of punched pieces 32 are punched out, the lowermost punched piece 32 falls downward and is discharged from the die 34 as shown in FIG.

  In this manner, the punched piece 32 is accumulated in the through hole 38 of the die 34 until discharged. However, if the biting force on the inner wall of the side pressure applying portion 39 is insufficient, the extraction piece 32 may jump out above the die 34. Various proposals have been made in order to prevent the protruding piece 32, also referred to as "slip-up", from popping upward.

  In the “punching machine” disclosed in Patent Literature 1, the lubricant attached to the punch end surface is prevented from being pulled upward from the through hole of the die. In order to prevent this drawing, the end face of the punch is coated with a material having a critical surface tension of 50 dyn / cm or less. This coating prevents the lubricant from adhering to the punch end face.

  The “slip-up prevention mold and its processing method” disclosed in Patent Document 2 is a punching mold for manufacturing a lead frame. In this mold, a groove is processed by pressing a grindstone against a local part on the inner surface of the die. And the die inner surface is finished to the roughness which has an uneven | corrugated shape by the protrusion around the groove | channel. This uneven shape improves the biting of the punched piece against the inner surface of the die and prevents the residue from rising.

Japanese Patent Laid-Open No. 06-238358 JP 09-314247 A

  As shown in FIG. 8, when the blade 33 a is formed at the tip of the punch 33 and the inside thereof is a recess 33 b, it is difficult for the residue to rise due to adhesion of the lubricant. For this reason, in this punch 33, the process concerning the surface tension of Patent Document 1 is unnecessary.

The concavo-convex shape portion of Patent Document 2 for improving the biting of the extracted piece is easily worn. Therefore, since periodic grooving is required, the maintenance cost increases.
As a punching process generally performed, the mold described with reference to FIGS. 8 and 9 finishes the dimensional accuracy and surface roughness of the inner wall of the lateral pressure applying portion 39 of the die 34 within a predetermined range. As a result, the biting piece 32 bites against the inner wall of the side pressure applying portion 39. For this reason, as shown in FIGS. 10 and 11, the inner wall of the lateral pressure applying portion 39 is ground using a grinder capable of precision grinding such as a jig grinder. This grinding is performed by moving the rotating grindstone 41 in the direction of the arrow 42 along the workpiece placement surface 34a.

  In grinding with respect to the lateral pressure applying portion 39, a streak-like grinding mark 43 appears along the moving direction of the grindstone 41 as shown in FIG. Since the grinding marks 43 have a concavo-convex shape continuous in the punching direction 37 of the punch 33, the convex and concave portions of the concavo-convex portion are easily worn by the press-contact movement of the outer peripheral portion of the punch piece 32. The worn side pressure applying portion 39 has an increased inner diameter. As a result, the biting piece 32 bites against the inner wall of the side pressure applying portion 39, and the punching piece 32 jumps out to the punch 33 side.

  In addition, the grinding marks 43 are removed by honing or the like, and the inner wall of the side pressure applying part 39 is made a surface with less unevenness. Thereby, since predetermined dimensional accuracy and surface roughness can be obtained, the amount of wear can be reduced, and the biting piece 32 can be kept from biting against the inner wall of the side pressure applying portion 39. However, there is a problem that processing costs increase.

  The present invention has been made paying attention to such a problem, and the object of the present invention is to bite the punched piece against the inner wall of the side pressure applying portion in the through hole of the die in the punching process repeated for a long time. Another object of the present invention is to provide a stamping die that is maintained well and a grinding method thereof.

  In order to solve the above-mentioned problem, the invention of the punching die according to claim 1 is characterized in that the metal plate is extracted by a punch and a die composed of a pair of halves in which a through hole allowing insertion of the punch is formed. In the punching die to be processed, grinding traces only in the direction along the punching direction of the punch are formed on the inner wall of the side pressure applying portion provided in the through hole and for accumulating punched punched pieces. It is characterized by.

  According to the said structure, the inner wall of the side pressure provision part in the through-hole of die | dye was made into the grinding finishing surface in which the grinding trace of only the direction along the punching direction was formed. For this reason, unlike the case where the grinding trace in the direction orthogonal to the punching direction is formed, the wear of the inner wall of the side pressure applying portion is difficult to proceed. For this reason, the biting force of the extraction piece with respect to the inner wall of the side pressure applying portion can be maintained for a long time.

  According to a second aspect of the present invention, in the punching die according to the first aspect, the through-hole includes a tapered hole portion for discharging the punched piece together with the side pressure applying portion. To do.

  The invention of the punching die grinding method according to claim 3 is the punching die grinding method according to claim 1, wherein the inner walls of the respective through-hole planned portions of the pair of half dies are It has a rotating shaft in a direction orthogonal to the punching direction of the punch, and finish grinding is performed by the outer peripheral surface of a disk-shaped grindstone that moves along the punching direction while rotating.

  According to the above configuration, each of the through hole planned portions of the pair of halves is formed by the disk-shaped grindstone that has the rotation axis in the direction perpendicular to the punching direction and moves along the punching direction while rotating. The inner wall was ground. For this reason, grinding traces only in the direction along the punching direction are formed on the inner wall of the through-hole planned portion. Therefore, when a die is formed using a pair of halves, the progress of wear on the inner wall of the side pressure applying portion of the die can be delayed. Moreover, since the finishing of the inner wall of the side pressure applying part by the honing process can be omitted, the machining cost can be reduced.

  According to a fourth aspect of the present invention, in the grinding method of the punching die according to the third aspect, the half mold is fixed on a horizontally movable and rotatable processing table, and the grinding stone and the half When the split mold inner wall is in a non-contact state, the grinding table is moved with the horizontal movement and rotation of the machining table, and the grinding position by the grindstone is shifted.

  According to the present invention, since the inner wall of the side pressure applying portion in the through hole of the die is a ground finish surface in which only the trace along the punching direction is formed, the grinding in the direction perpendicular to the punching direction is performed. Unlike the case where a mark is formed, the inner wall of the side pressure applying portion is hardly worn. Therefore, it is possible to provide a punching die capable of maintaining the biting force of the punched piece against the inner wall of the side pressure applying portion for a long time.

The perspective view which shows the punching die which consists of a pair of half mold in embodiment. The perspective view which shows a half type | mold. AA arrow sectional drawing in FIG. The partial cross section figure which shows the aspect of half type grinding. The top view which shows the aspect of grinding with respect to the half type | mold which changes an attitude | position in order of (a)-(c). The front view which shows the grinding locus in a through-hole planned part. The top view which shows the workpiece | work punched out. Sectional drawing which shows the aspect just before a workpiece | work is punched by the punching die of a prior art. Sectional drawing which shows the aspect by which the workpiece | work was punched by the said punching die. The top view which shows the aspect of grinding of the side pressure provision part of the die | dye of a prior art. BB arrow sectional drawing of FIG. The enlarged view which shows a grinding surface.

(Embodiment)
Hereinafter, embodiments embodying the present invention will be described with reference to FIGS. In addition, about the same structure as a prior art, the same code | symbol used in the description shall be used.

  As shown in FIGS. 1 to 3, the die 1 of the punching die according to the present embodiment has a pair of halves 1 a and 1 b joined to each other at the joining surface 5, and the installation portion of the die holder 35. It is used by installing in 35a. The through hole 38 having an elliptical shape in plan view of the installed die 1 includes a side pressure applying portion 39 and a tapered hole portion 40.

  The half mold 1a is a rectangular parallelepiped having an upper surface 6a and a lower surface 7a parallel to each other, and the half mold 1b is a rectangular parallelepiped having an upper surface 6b and a lower surface 7b parallel to each other. Each of the pair of halves 1a and 1b includes a side pressure application planned portion 3 and a tapered hole planned portion 4 as the through hole planned portion 2 on one side surface side in the longitudinal direction. The respective side pressure application scheduled portions 3 are arranged to face each other and become side pressure application portions 39, and the respective tapered hole planned portions 4 are arranged to face each other to become a tapered hole portion 40. The lower surfaces 7 a and 7 b are surfaces orthogonal to the punching direction 37 of the punch 33.

  A grinding mark 44 only in the direction along the drawing direction 37 is formed on the inner wall 3 b of the side pressure application scheduled portion 3. Although this grinding mark 44 is drawn in a streak shape for easy understanding in the enlarged view of FIG. 2, it is actually a mark that cannot be visually recognized by the naked eye. In the embodiment, the surface on which the grinding marks 44 are formed has an average roughness (Ra) of the center line of 0.2a or less.

  As shown in FIG. 4, in the grinding process, the half mold 1 a is fixed to a magnet chuck 11 on a processing table 10 that can move horizontally and rotate about a vertical rotation axis. Further, the grindstone 12 for grinding the half mold 1a is supported by a machine body (not shown) so as to be movable in the vertical direction and in the front-rear direction with respect to the grindstone 12. With such a configuration, in order to form the through hole 38 having a three-dimensional curved surface, the contouring grinding is performed on the side pressure application scheduled portion 3 and the tapered hole planned portion 4 of the half mold 1a.

  And the grinding process with respect to the inner wall 3b of the half mold 1a and the inner wall 4b of the taper-shaped hole planned part 4 has the rotating shaft 12a (refer FIG. 5) of the direction orthogonal to the drawing direction 37, and follows the drawing direction 37. This is performed by the outer peripheral surface of the disc-shaped grindstone 12 that moves while rotating. That is, as shown in FIG. 4, the movement from the center position C1 of the grindstone 12 at the position for grinding the inner wall 3b to the center position C2 of the grindstone 12 at the position for grinding the inner wall 4b is a plane including the punching direction 37. It is along.

  Further, as shown in FIG. 5A, the rotating grindstone 12 moves along a plane perpendicular to the plane of the paper (including the drawing direction 37), and the end inner wall 3a and the taper of the side pressure application scheduled portion 3. The end inner wall 4a of the shaped hole planned portion 4 is ground. When one grinding process by the grindstone 12 is completed, the tip 12b of the grindstone 12 and the end inner walls 3a, 4a are in a non-contact state. In this non-contact state, the half mold 1a rotates in the clockwise direction and moves in the horizontal direction, and is aligned with the start position of the next grinding process by the tip portion 12b.

  In this way, the grinding of the end inner wall 3a and the end inner wall 4a and the movement of the grinding position by the rotation of the half mold 1a are repeated to grind the inner wall of one end of the half mold 1a. Done. And as shown to Fig.5 (a)-(c), the grinding process with respect to the half mold 1a is performed, changing the position of a grinding process from one edge part to the other edge part. That is, as shown in FIG. 6, when the front end 12b of the grindstone 12 and the end inner walls 3a, 4a are not in contact with each other, the front end 12b is relatively laterally moved by the rotation of the half mold 1a. It moves to the next grinding start position following the course S2 in the direction. During grinding, as the grindstone 12 moves, the distal end portion 12b moves along the longitudinal path S1. Accordingly, only the grinding marks 44 in the direction along the drawing direction 37 are formed on the inner wall 3b including the end inner wall 3a of the side pressure application scheduled portion 3 as shown in FIG.

  In the case of this grinding mark 44, unlike the conventional technique that is easily worn due to the concavo-convex shape in the punching direction 37 of the punch 33 like the grinding mark 43 shown in FIG. The amount of wear due to the parts moving in pressure contact is small. Therefore, the inner wall of the side pressure applying portion 39 constituting a part of the through hole 38 of the die 1 is not easily worn even if the outer peripheral portion of the extraction piece 32 repeatedly passes in the pressed state. For this reason, the die 1 of the present embodiment can extend the time during which the biting state of the punched piece 32 with respect to the lateral pressure applying portion 39 can be kept good, as compared with the conventional die 34. That is, the life of the punching die can be extended. Since it becomes difficult to generate | occur | produce the chip | tip in the opening edge of the side pressure provision part 39, the lifetime of a stamping die can be further extended.

In addition, in the grinding process of the said embodiment, although the half mold 1a was described, the grinding process with respect to the half mold 1b is performed similarly.
In the present embodiment, the inner walls of the side pressure application planned portion 3 and the tapered hole planned portion 4 are continuously ground as one stroke, but only the inner wall of the side pressure application planned portion 3 is You may make it finish-grind so that the course S1 of a direction may be followed. Then, when the inner wall of the tapered hole planned portion 4 is ground so as to have an appropriately rough finished surface by the grindstone 12 moving in an arbitrary direction, the processing time related to finish grinding can be shortened.

Therefore, according to the above embodiment, the following effects can be obtained.
(1) In the above embodiment, the inner wall of the side pressure applying portion 39 constituting a part of the through hole 38 of the die 1 is a finish grinding surface on which only the grinding marks 44 in the direction along the punching direction 37 of the punch 33 are formed. I was there. For this reason, it is possible to reduce the amount of wear due to the outer peripheral portion of the extraction piece 32 passing through the side pressure applying portion 39 in a pressure contact state. Further, chipping at the opening edge of the side pressure applying portion 39 is difficult to occur. Therefore, the life of the punching die can be extended.

  (2) In the above embodiment, the inner wall of the lateral pressure applying portion 39 is ground so that only the grinding marks 44 in the direction along the punching direction 37 of the punch 33 are formed, and the average roughness of the center line on the grinding surface ( Precision grinding was performed so that Ra) was 0.2a or less. For this reason, unlike the case where the grinding marks 43 formed in the direction crossing the punching direction 37 are removed by honing or the like, the finishing cost of the inner wall of the side pressure applying portion 39 can be reduced.

  (3) In the said embodiment, the die | dye 1 was comprised by a pair of half type | molds 1a and 1b. Then, the inner walls of the side pressure application planned portion 3 and the tapered hole planned portion 4 in each half mold 1a, 1b are finished by contouring grinding. For this reason, the die | dye 1 provided with the through-hole 38 which has a three-dimensional curved surface of arbitrary shapes can be formed easily.

(Example of change)
In addition, the said embodiment can also be changed and actualized as follows.
-Although the shape of the pair of halves 1a, 1b is the target shape, it should be asymmetric.

Further, technical ideas that can be grasped from the above-described embodiment are described below together with their effects.
(A) The punch wall according to claim 1, wherein the inner wall of the lateral pressure imparting portion is a ground surface having an average roughness (Ra) of a center line finished by grinding of 0.2a or less. Type. In the case of such a configuration, it is not necessary to remove grinding marks by honing, so that the number of processing steps can be reduced.
(B) The punching die according to claim 1 or (A), wherein the through hole has a three-dimensional curved surface ground by a contouring process. When comprised in this way, the die | dye provided with the through-hole which has a three-dimensional curved surface of arbitrary shapes can be formed easily.

    DESCRIPTION OF SYMBOLS 1,34 ... Die, 1a, 1b ... Half type, 2 ... Through-hole planned part, 3b, 4b ... Inner wall, 10 ... Processing table, 12 ... Grinding wheel, 12a ... Rotary shaft, 32 ... Extraction piece, 33 ... Punch, 37 ... Extraction direction, 38 ... Through hole, 39 ... Side pressure applying part, 40 ... Tapered hole part, 43, 44 ... Grinding marks.

Claims (4)

  In a punching die for punching a metal plate by a punch and a die composed of a pair of halves formed with a through hole allowing the punch to be inserted, a punched piece provided in the through hole and punched A punching die having a grinding mark formed only in a direction along a punching direction of the punch is formed on an inner wall of a side pressure applying portion for storing the pressure.   2. The punching die according to claim 1, wherein the through-hole is provided with a tapered hole portion for discharging the punched piece together with the side pressure applying portion.   2. The punching die grinding method according to claim 1, wherein an inner wall of each through-hole portion of each of the pair of halves has a rotation axis in a direction perpendicular to the punching direction and rotates. A grinding method for a punching die, characterized in that finish grinding is performed by an outer peripheral surface of a disc-shaped grindstone that moves along the punching direction.   The half mold is fixed on a horizontally movable and rotatable machining table, and when the grindstone and the half mold inner wall are in a non-contact state, the machining table is moved horizontally and rotated. 4. The punching die grinding method according to claim 3, wherein the grinding position of the grinding stone is shifted by being moved.

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