JP2007326105A - Press forming die and press forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a press forming die by which the generation of rolling of a material to be worked is prevented and bruises and whisper burs are prevented from being generated on the material to be worked. <P>SOLUTION: A pinching parts 13 with which a lead frame material 2 placed on a die 5 and heel parts 15a, 15b by which the side faces of the lead frame material 2 are positioned are formed on punch guides 11, and the side faces of the heel parts 15a, 15b are composed of straight-like position control surfaces the upper ends of which reach the pinching parts 13 and circular-arcuate guide faces which are continued to the under surfaces of the heel parts 15a, 15b from the lower ends of the position control surfaces. Projection parts 20a, 20b for positioning the side faces of the lead frame material 2 are formed on a die 5. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a press molding die and a press molding method for punching a metal plate-like workpiece such as a lead frame.

  As a conventional press mold, when manufacturing thin metal plates (workpieces) such as lead frames or lead cutting of semiconductor devices, etc., it is punched into the lead frame by punch punching pressure or friction force. Since traces and deformation are likely to occur, there is one in which a metal plate material is narrowly supported by a punch guide and punched by a punch and press-molded (for example, see Patent Document 1 below).

  That is, FIG. 8 shows the conventional press-molding die 50 described in the above-mentioned Patent Document 1. The lead frame material 51 is pressed by a plurality of processing stages while the lead frame material 51 is fed forward. It is to be processed into a product.

  The press mold 50 includes a die 52 on which the lead frame material 51 is placed, a punch guide 53 that narrows the lead frame material 51 between the die 52, and a lead frame material that is narrowly pressed by the punch guide 53. A punch 54 for punching 51 is provided. The punch guide 53 supports the lead frame material 51 by forming a narrow pressure portion 55 for narrowing the lead frame material 51 between the die 52 and a C-face with the outer surface of the lead frame material 51. A tapered surfaced portion 56 is formed.

According to this, after the first press punching process is performed on the lead frame material 51 in the preceding processing stage, the lead frame material 51 is sequentially fed to the next processing stage and placed on the die 52, and the punch guide 53 is moved. The lead frame material 51 is lowered toward the die 52, and the lead frame material 51 is narrowed between the narrow pressure portion 55 of the punch guide 53 and the die 52. In this state, the punch 54 descends while being guided by the punch guide 53. Punch 51. According to such a press-molding die 50, when the lead frame material 51 is fed forward, even if the position of the lead frame material 51 is slightly deviated from the normal position, dents or beards are generated on the product. Can be prevented.
JP-A-6-232306

  However, in the conventional press-molding die 50, as shown in FIG. 9A, when the lead frame material 51 is punched with the punch 54, the lead frame material 51 is in a direction orthogonal to the punching direction A of the punch 54. In order to escape to B and to get up by being pulled in the punching direction A, the punching direction A is defined with one corner C facing the intersection of the side surface of the punch 54 and the narrow pressure portion 55 as a fulcrum. It becomes easy to fall in the opposite direction D. When the lead frame material 51 rolls in such a direction D, the other corner E facing the opposite side (die 52 side) diagonally from the one corner C of the lead frame material 51 is the largest. There is a problem that the lead frame material 51 is deformed due to vibration.

  In order to reduce the occurrence of the rolling of the lead frame material 51 as described above, for example, it is conceivable to increase the pressing force of the punch guide 53 to the die 52. It is necessary to increase the strength of 52, there is a need to increase the size of the press mold 50, and there is a problem that the lead frame material 51 itself is deformed, for example, a step.

  Alternatively, as shown in FIG. 9B, there is a punch guide 53 provided with a protruding heel portion 58 for positioning the side surface of the lead frame material 51. The side surface of the heel portion 58 is a flat straight surface.

  According to this, when the lead frame material 51 is narrowed between the narrow pressure portion 55 of the punch guide 53 and the die 52, the outer surface of the lead frame material 51 is positioned by the heel portion 58. Further, when the lead frame material 51 is punched with the punch 54, the outer surface of the lead frame material 51 abuts against the side surface of the heel portion 58, so that the lead frame material 51 can be reliably prevented from escaping in the direction B.

  However, when the lead frame material 51 is fed forward, if the position of the lead frame material 51 is deviated from the normal position, the heel portion 58 of the punch guide 53 interferes with the lead frame material 51 while descending, and a dent is generated in the product. There is a problem that a shaving 59 occurs.

  The present invention provides a press-molding die and a press-molding method that can prevent the workpiece from rolling and prevent the workpiece from being dented or shaved. With the goal.

In order to achieve the above object, a press molding die according to the first invention includes a die for placing a plate-like workpiece, a punch guide for narrowing the workpiece between the dies, and a punch guide. A press mold having a punch for punching a workpiece that has been subjected to narrow pressure,
A mounting part is formed on the die,
The punch guide is formed with a narrow pressure portion for narrowing the workpiece placed on the placement portion,
The die is formed with a protrusion for positioning the side surface of the workpiece placed on the placement portion.

  According to this, when the work piece is placed on the placing portion and the work piece is tightly pressed between the narrow pressure portion of the punch guide and the die, the side surface of the work piece is positioned by the protruding portion of the die. The In this state, the punch moves in the punching direction while being guided by the punch guide to punch the workpiece.

  At this time, even if the work piece rolls around one corner facing the intersection of the side surface of the punch and the narrow pressure portion of the punch guide as a fulcrum, it is opposite to the one corner of the work piece diagonally. Since the deflection of the other corner facing the side is blocked by the protrusion of the die, the other corner of the workpiece that has been most easily shaken in the past is fixed, ensuring the occurrence of rolling of the workpiece Can be prevented.

  Therefore, it is not necessary to increase the pressing force of the punch guide to the die and prevent the punch guide or die from increasing in strength in order to prevent the occurrence of falling. Thereby, the press mold does not increase in size, and further, deformation such as a step in the workpiece itself can be prevented.

The press molding die according to the second invention includes a die for placing a plate-like workpiece, a punch guide for narrowing the workpiece between the dies, and a workpiece that is narrowed by the punch guide. A press mold having a punch for punching,
A mounting part is formed on the die,
The punch guide is formed with a narrow pressure portion for narrowing the workpiece placed on the placement portion and a protruding heel portion for positioning the side surface of the workpiece,
The side surface of the heel portion is composed of a straight position restricting surface with one end reaching the narrow pressure portion and an arcuate guide surface continuing from the other end of the position restricting surface to the surface facing the die. .

  According to this, when the workpiece is placed on the placing portion and the workpiece is narrowed between the narrow pressure portion of the punch guide and the die, the side surface of the workpiece is controlled by the position regulating surface of the heel portion. Positioned. In this state, the punch moves in the punching direction while being guided by the punch guide to punch the workpiece.

  In addition, when the work placement position deviates from the normal position of the placement portion, when the work piece is narrowed between the narrow pressure portion of the punch guide and the die, the work piece is It is guided to the guide surface and corrected to the normal position, and is smoothly introduced to the position regulating surface of the heel portion. Thereby, it can prevent that a dent and a beard arise in a workpiece. Furthermore, since the side surface of the workpiece is positioned by the position regulating surface of the heel portion, it is effective for preventing the workpiece from rolling.

The press-molding die in the third invention comprises a die for placing a plate-like workpiece, a punch guide for narrowing the workpiece between the dies, and a workpiece that is narrowed by the punch guide. A press mold having a punch for punching,
A mounting part is formed on the die,
The punch guide is formed with a narrow pressure portion for narrowing the workpiece placed on the placement portion and a protruding heel portion for positioning the side surface of the workpiece,
The die is formed with a protrusion for positioning the side surface of the workpiece placed on the placement portion.

  According to this, when the work piece is placed on the placing portion and the work piece is pressed between the narrow pressure portion of the punch guide and the die, the side surface of the work piece is the protrusion of the die and the punch guide. And the heel part of the head. In this state, the punch moves in the punching direction while being guided by the punch guide to punch the workpiece.

  At this time, even if the work piece rolls around one corner facing the intersection of the side surface of the punch and the narrow pressure portion of the punch guide as a fulcrum, it is opposite to the one corner of the work piece diagonally. Since the deflection of the other corner facing the side is blocked by the protrusion of the die, the other corner of the workpiece that has been most easily shaken in the past is fixed, ensuring the occurrence of rolling of the workpiece Can be prevented. Further, positioning the side surface of the workpiece by the position regulating surface of the heel portion is also effective for preventing the workpiece from rolling.

  In the press molding die according to the fourth aspect of the invention, the side surface of the heel portion has a straight position restricting surface whose one end reaches the narrow pressure portion, and an arc shape continuous from the other end of the position restricting surface to the surface facing the die. It consists of a guide surface.

  According to this, when the work position is shifted from the normal position of the placement portion, when the work piece is narrowed between the narrow pressure portion of the punch guide and the die, the work piece is It is guided to the normal position by being guided by the guide surface of the heel portion, and is smoothly introduced to the position regulating surface of the heel portion. Thereby, it can prevent that a dent and a beard arise in a workpiece.

In the press molding die according to the fifth aspect of the invention, the heel portion and the projection portion are respectively disposed in pairs in one direction orthogonal to the punching direction by the punch,
The position of the heel part and the position of the protrusion part are shifted so as not to overlap in the other direction perpendicular to the punching direction and one direction.

According to this, since the residual stress in the workpiece generated by the punching force at the time of punching is dispersed, deformation of the workpiece can be prevented.
Further, the height of the heel portion is not limited by the protrusion, and the height of the protrusion is not limited by the heel portion. Therefore, the degree of freedom in designing the heel part and the protrusion part is improved.

The press molding method according to the sixth aspect of the invention includes a die for placing a plate-like workpiece, a punch guide for narrowing the workpiece between the dies, and a workpiece that has been narrowed by the punch guide. A press molding method using a press mold having a punch to be processed,
Placing the workpiece on the die, fitting the workpiece between a pair of protrusions formed on the die, and positioning the side surface of the workpiece;
The punch guide is moved toward the die, the workpiece is fitted between a pair of heel portions formed on the punch guide, the side surface of the workpiece is positioned, and the workpiece is positioned between the die and the punch guide. A process of narrowing pressure;
And a step of punching a workpiece with a punch.

  According to this, when punching a workpiece with a punch, even if the workpiece tries to roll with one corner facing the intersection of the side surface of the punch and the narrow pressure portion of the punch guide as a fulcrum, Because the deflection of the other corner facing the opposite side of the diagonal from the one corner of the workpiece is blocked by the protrusion of the die, the other corner of the workpiece that has been the most prone to swing in the past is fixed Therefore, it is possible to reliably prevent the workpiece from falling. Further, positioning the side surface of the workpiece by the heel portion is also effective for preventing the workpiece from rolling.

  As described above, according to the present invention, the occurrence of rolling of the workpiece can be reliably prevented, and the enlargement of the press mold and the deformation of the workpiece can be prevented. Further, it is possible to prevent dents and beards from occurring on the workpiece. Furthermore, the residual stress in the workpiece can be dispersed to prevent the workpiece from being deformed, and the degree of freedom in designing the heel portion and the projection portion can be improved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIGS. 1 and 2, reference numeral 1 denotes a press molding die for press molding a lead frame material 2 (an example of a workpiece) which is a thin metal plate material. This press-molding die 1 performs press molding at a plurality of processing stages while sequentially feeding the lead frame material 2 to process the lead frame material 2 into a product, and is configured as follows.

  The press molding die 1 is composed of a lower fixed die 3 and an upper movable die 4. The fixed mold 3 has a die 5, and the die 5 is provided with a placement portion 6 on which the lead frame material 2 is placed and a hole 7 that opens on the upper surface of the die 5.

  The movable mold 4 has a punch 10 for punching the lead frame material 2 and a punch guide 11 for guiding the punch 10. The punch 10 is inserted into a guide hole 12 formed in the punch guide 11 and can move up and down in a punching direction Xa (downward) and a retreating direction Xb (upward) opposite to the punching direction Xa. Further, the punch guide 11 can be moved up and down in the same direction as the punch 10 separately from the punch 10. The punch guide 11 includes a pinching portion 13 for pinching the lead frame material 2 placed on the placement portion 6 between the die 5 and a pair of protruding heel portions for positioning the side surfaces of the lead frame material 2. 15a and 15b are formed.

  As shown in FIGS. 1 to 3, both heel portions 15 a and 15 b are arranged at two locations on both sides of the guide hole 12, and are in one direction Y orthogonal to the punching direction Xa (that is, the forward feed direction of the lead frame material 2). ). The side surfaces of the heel portions 15a and 15b are opposed to each other in one direction Y, and are formed from a straight position restricting surface 16 whose upper end (one end) reaches the clamping portion 13 and a lower end (other end) of the position restricting surface 16. The heel portions 15a and 15b are configured by an arcuate guide surface 17 continuous to the lower surface (that is, the surface facing the die 5).

  The height H of each heel portion 15a, 15b is set to approximately 2/3 (that is, H = T × 2/3) of the plate thickness T (see FIG. 5) of the lead frame material 2. The radius R of the guide surface 17 is set to about 50 μm.

  On the die 5, projections 20 a and 20 b for positioning the side surface of the lead frame material 2 placed on the placement part 6 are formed at four locations on both sides of the hole 7. That is, the pair of protrusions 20a and 20b are opposed in one direction Y, and two sets are provided in the other direction Z orthogonal to the punching direction Xa and the one direction Y as shown in FIG. . The side surfaces of the protrusions 20a and 20b are opposed to each other in one direction Y. From the straight position regulating surface 21 whose lower end (one end) reaches the mounting portion 6 and the upper end (the other end) of the position regulating surface 21. An arcuate guide surface 22 that is continuous with the upper surfaces of the protrusions 20a and 20b (that is, the surface facing the punch guide 11).

  As shown in FIGS. 1 and 4, the positions of the pair of heel portions 15 a and 15 b in the other direction Z are such that the positions of the pair of protrusion portions 20 a and 20 b do not overlap the positions of the pair of heel portions 15 a and 15 b. It is shifted to both outsides. Further, as shown in FIG. 3, the height h of each protrusion 20a, 20b is set slightly higher than 1/3 of the plate thickness T of the lead frame material 2 (ie, H = T × 1/3). . Moreover, the lower part of the heel parts 15a and 15b and the upper part of the projection parts 20a and 20b overlap.

Next, a press molding method using the press mold 1 will be described.
(1) First, the lead frame material 2 is placed on the die 5 and, as shown in FIG. 5, the first punching process is performed on the lead frame material 2 using another punch 26 in the preceding processing stage 29. The punching hole 27 is formed in the lead frame material 2. The side surface of the lead frame material 2 facing the punched hole 27 becomes a shear surface S1 in the range of about 2/3 of the plate thickness T from the upper surface, and in the range of about 1/3 of the remaining plate thickness T. The fracture surface S2. The shear surface S1 is a relatively smooth surface, and the fracture surface S2 is rougher than the shear surface S1 and slightly bites inward.

  (2) After the first punching process is performed on the lead frame material 2 as described above, the lead frame material 2 is sequentially fed to the next processing stage 30 as shown in FIG. 6, the lead frame material 2 is fitted between the pair of projecting portions 20 a and 20 b, and the side surface of the lead frame material 2 is positioned by the position regulating surface 21 of the projecting portions 20 a and 20 b.

  (3) Next, as shown in FIG. 6, the punch guide 11 is lowered toward the die 5, and the lead frame material 2 is fitted between the pair of heel portions 15 a and 15 b, so that the side surface of the lead frame material 2 is The lead frame material 2 is narrowed between the die 5 and the narrow pressure portion 13 of the punch guide 11 while being positioned by the position restricting surfaces 16 of the heel portions 15a and 15b. At this time, the narrow pressure portion 13 narrows the upper surface of the lead frame material 2 with a predetermined pressing amount (for example, 0.02 mm to 0.03 mm).

  (4) Thereafter, as shown in FIG. 7, the punch 10 is lowered in the punching direction Xa, and the lead frame material 2 is punched. Thereby, the lead (product) is press-molded from the lead frame material 2. Incidentally, the portion 31 indicated by a two-dot chain line of the lead frame material 2 shown in FIG.

The above is the description of the press molding method.
Below, the effect in the said press molding method is demonstrated.
In the molding method (2), when the lead frame member 2 is fitted between the pair of protrusions 20a and 20b, the lead frame member 2 guides the protrusions 20a and 20b as shown in FIGS. It is guided by the surface 22 and smoothly introduced and fitted between the pair of protrusions 20a and 20b.

  Further, in the molding method (3), when the placement position of the lead frame material 2 is deviated from the normal position of the placement portion 6, the lead frame material 2 is moved between the narrow pressure portion 13 and the die 5. When the pressure is reduced, the lead frame member 2 is guided to the normal position by being guided by the guide surfaces 17 of the heel portions 15a and 15b, and smoothly introduced between the pair of heel portions 15a and 15b as shown in FIG. It fits in. Thereby, it is possible to prevent dents and beards from occurring in the lead frame material 2.

  In addition, when punching with the punch 10 in (4) of the molding method, as shown in FIG. 7, one corner of the lead frame material 2 facing the intersection of the side surface of the punch 10 and the narrow pressure portion 13 is formed. Even if it tries to roll with the portion C as a fulcrum, the deflection of the other corner E facing the opposite side of the corner C of the lead frame material 2 is prevented by the protrusions 20a and 20b. The other corner E of the lead frame material 2 that was most likely to swing is fixed, and the lead frame material 2 can be reliably prevented from rolling.

  Therefore, it is not necessary to increase the pressing force of the punch guide 11 to the die 5 and prevent the punch guide 11 and the die 5 from increasing in strength in order to prevent the occurrence of falling. Thereby, the press molding die 1 is not increased in size, and further, deformation such as a step in the lead frame material 2 itself can be prevented.

Further, positioning the side surfaces of the lead frame material 2 by the heel portions 15a and 15b is also effective for preventing the lead frame material 2 from rolling.
Also, as shown in FIGS. 1 and 4, the heel portions 15a and 15b and the projection portions 20a and 20b are displaced in the other direction Z so as not to overlap each other. The residual stress generated in the lead frame material 2 is dispersed, and the deformation of the lead frame material 2 can be prevented. Further, the height H of the heel portions 15a and 15b is not limited by the protrusion portions 20a and 20b, and the height h of the protrusion portions 20a and 20b is not limited by the heel portions 15a and 15b. Therefore, the freedom degree at the time of designing the heel parts 15a and 15b and the projection parts 20a and 20b improves.

  The height H of the heel portions 15a and 15b is set to approximately 2/3 of the plate thickness T of the lead frame material 2, and the height h of the protrusions 20a and 20b is set to approximately 1 of the plate thickness T of the lead frame material 2. By setting to / 3, as shown in FIG. 7, the position restricting surfaces 16 of the heel portions 15a and 15b abut against the shear surface S1 on the side surface of the lead frame material 2, and the position restricting surfaces 21 of the projecting portions 20a and 20b. Contacts the fracture surface S2 on the side surface of the lead frame member 2. The lead frame material 2 can be positioned more accurately by bringing the position restricting surfaces 16 and 21 into contact with the two types of surfaces S1 and S2 having different properties.

  In the above-described embodiment, the height H of the heel portions 15a and 15b is set to 2/3 of the plate thickness T of the lead frame material 2, but it may be other than 2/3 of the plate thickness T. The plate thickness T may be set within a range of 1/3 to 2/3.

  In the above embodiment, the height h of the protrusions 20a and 20b is set slightly higher than 1/3 of the plate thickness T of the lead frame material 2, but is set to exactly 1/3 of the plate thickness T. Alternatively, it may be set to a value other than 1/3 of the plate thickness T.

  In the embodiment described above, the radius R of the guide surface 17 of the heel portions 15a and 15b is set to 50 μm. However, the radius R is not limited to 50 μm, and for example, the radius R is set within a range of 30 to 70 μm. May be.

In the embodiment, as shown in FIG. 3, the guide surfaces 22 of the protrusions 20a and 20b are formed in an arc shape, but may be formed in a taper shape.
In the embodiment, as shown in FIG. 1, four protrusions 20a, 20b are formed on both sides of the hole 7 of the die 5, but a plurality other than four may be formed.

In the embodiment, two heel portions 15a and 15b are formed on both sides of the guide hole 12 of the punch guide 11. However, a plurality other than the two may be formed.
In the above-described embodiment, the lead frame material 2 has been described as an example of the workpiece, but the lead frame material 2 is not limited thereto.

  It is useful as a press molding die and a press molding method used in the manufacture of metal thin plate materials such as lead frames or lead cutting of semiconductor devices, and particularly for lead frames that require finer lead processing than the thickness of the metal thin plate material. Suitable for molding process.

It is a perspective view of the press molding die in embodiment of this invention. FIG. 6 is a longitudinal sectional view of the press mold, showing a state in which the lead frame material is placed on the placement portion. FIG. 3 is an enlarged view of a side surface of a heel portion and a side surface of a protruding portion of the press molding die. It is a figure which shows arrangement | positioning in the other direction Z of the heel part and projection part of a press molding die similarly. FIG. 3 is a view of a lead frame material punched out at the preceding processing stage of the press mold. FIG. 4 is a longitudinal sectional view of the press mold, showing a state in which a lead frame material is sandwiched between a die and a punch guide. FIG. 2 is a longitudinal sectional view of the press mold, showing a state in which the lead frame material is punched out with a punch. It is a longitudinal cross-sectional view of the conventional press-molding metal mold | die, and shows the state which pinched the lead frame material between die | dye and a punch guide. It is a longitudinal cross-sectional view of the conventional press molding die, (a) shows generation | occurrence | production of the lead frame material rolling, (b) has shown generation | occurrence | production of the beard of the lead frame material.

Explanation of symbols

1 Press mold 2 Lead frame material (workpiece)
5 Die 6 Placement part 10 Punch 11 Punch guide 13 Clamping part 15a, 15b Heel part 16 Position regulation surface 17 Guide surface 20a, 20b Protrusion part Xa Punching direction Y One direction Z Other direction

Claims (6)

A press-molding metal comprising a die for placing a plate-like workpiece, a punch guide for narrowing the workpiece between the dies, and a punch for punching the workpiece that has been narrowed by the punch guide Type,
A mounting part is formed on the die,
The punch guide is formed with a narrow pressure portion for narrowing the workpiece placed on the placement portion,
A press-molding die, wherein a projection for positioning a side surface of a workpiece placed on a placement portion is formed on a die. A press-molding metal comprising a die for placing a plate-like workpiece, a punch guide for narrowing the workpiece between the dies, and a punch for punching the workpiece that has been narrowed by the punch guide Type,
A mounting part is formed on the die,
The punch guide is formed with a narrow pressure portion for narrowing the workpiece placed on the placement portion and a protruding heel portion for positioning the side surface of the workpiece,
The side surface of the heel portion is composed of a straight position restricting surface, one end of which reaches the narrow pressure portion, and an arcuate guide surface that continues from the other end of the position restricting surface to the surface facing the die. Press mold. A press-molding metal comprising a die for placing a plate-like workpiece, a punch guide for narrowing the workpiece between the dies, and a punch for punching the workpiece that has been narrowed by the punch guide Type,
A mounting part is formed on the die,
The punch guide is formed with a narrow pressure portion for narrowing the workpiece placed on the placement portion and a protruding heel portion for positioning the side surface of the workpiece,
A press-molding die, wherein a projection for positioning a side surface of a workpiece placed on a placement portion is formed on a die. The side surface of the heel portion is composed of a straight position restricting surface, one end of which reaches the narrow pressure portion, and an arcuate guide surface that continues from the other end of the position restricting surface to the surface facing the die. The press-molding die according to claim 3. Each of the heel part and the protrusion part is arranged in a pair in one direction orthogonal to the punching direction by the punch,
5. The press molding according to claim 3, wherein the position of the heel portion and the position of the protrusion portion are shifted so as not to overlap in another direction orthogonal to the punching direction and one direction. Mold. A press-molding metal comprising a die for mounting a plate-like workpiece, a punch guide for narrowing the workpiece between the dies, and a punch for punching the workpiece pressed by the punch guide A press molding method using a mold,
Placing the workpiece on the die, fitting the workpiece between a pair of protrusions formed on the die, and positioning the side surface of the workpiece;
The punch guide is moved toward the die, the workpiece is fitted between a pair of heel portions formed on the punch guide, the side surface of the workpiece is positioned, and the workpiece is placed between the die and the punch guide. A process of narrowing pressure;
And a step of punching a workpiece with a punch.

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