JPH06218697A - Stripper plate for progressive metal mold - Google Patents

Abstract

PURPOSE:To carry out fine pressing work with high precision for a thin member which is as easily deformed as a lead frame in the press work. CONSTITUTION:All the periphery along the shape of a punch insertion part 11 on the pulling-out stage 4a of a stripper plate 4 is formed to a projection part 20 having a prescribed width, and the region which requires pressing force of the projection part 20 is formed to a flat pressing surface 20a, and other region is formed to a tapered pressing surface 20b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stripper plate of a progressive die capable of performing fine press working on a thin member such as a lead frame with high accuracy.

[0002]

2. Description of the Related Art As is well known, a printed wiring board on which a semiconductor integrated circuit or the like is mounted has been designed for high density and high mounting. For this reason, the lead frame used is also a finer and thinner member. Is coming.

As a metal-pressing die for press-working such a miniaturized thin member, a progressive die as shown in FIG. 3 is generally used.

In the schematic structure of this progressive die, first, a stripper holder 3 is attached to an upper sub 2 on the upper die 1 side of the die, and a stripper plate 4 is attached to the stripper holder 3. As the stripper plate 4, the removal stages 4a (see FIG. 4) are arranged at a predetermined interval, and the stripper plate 4 has a so-called integral structure or a structure close to it as a whole.

On the lower die 5 side, a die plate 8 is attached on the lower sub 6 via a lower packing plate 7 which is a floor plate. Then, between the stripper plate 4 on the side of the upper die 1 and the die plate 8 on the side of the lower die 5 described above, a coiled press-cutting material 10 to be a product as shown by a dotted line in the drawing is provided on the upper die 1 Then, the lower die 5 is inserted from the inlet end to the outlet end (in the direction of the arrow in the figure), is sequentially fed, and the punching process of the punching stages 4a is sequentially performed to obtain a finished processed product. Further, 9 is a stripper provided on the upper mold 1, and 9a is a spring for applying a pressing force to the stripper 9.

On the other hand, in the press working, as shown in FIG. 4, the punching stage 4a such as the lead frame 10a is used.
The stripper plate 4 provided with is attached to the stripper holder 3, and the punch 9b is inserted into the punch insertion portion 11 while pressing the punching material 10 inserted between the stripper holder 3 and the lower sub 8 of the lower die 5. It is pressed,
The region of the stripper plate 4 that follows the shape of the punch insertion portion 11 is formed as follows.

For example, in the case of a lead frame 10a of a punched product as shown in FIG. 5, the pressing surface of the stamping material 10 on the stripper plate 4 is entirely flat (see FIG. 7) or the pressing surface is convex. Either structure is adopted, which is formed as the portion 12 and the pressing surface is flat (see FIG. 8). The numerical values in FIG. 5 are in mm.

[0008]

However, in such a conventional progressive die, when the stripper 9 is pressed against the press-cut material 10 and punching is performed by the press working, the press-cut material 10 is horizontally, vertically and vertically pressed. There is a problem that it is difficult to maintain a predetermined accuracy because deformation such as a movement (flare) occurs in the twisting direction.

Therefore, when a fine thin member such as the lead frame 10a is pressed, the internal distortion of the material is particularly likely to cause the processing distortion and the so-called lead deformation occurs. . Therefore, it is difficult to stabilize the lead position of the lead frame 10a after press working, and there is a problem that quality improvement is required.

Incidentally, X in FIG. 6 is an explanatory view showing a warped state of the lead frame 10a when viewed from the longitudinal direction, and Y (±) shows an upper right (+) and a left downward (when viewed from the thickness direction of the lead frame 10a ( It is explanatory drawing which shows the twisted state of-).

As a result of earnest research in view of such circumstances, the present inventors have found that, for example, the lead deformation as described above is within 30% of the entire length from the tip of the lead frame 10a (see H in FIG. 6). ), It was found that effective prevention measures against lead deformation were found.

[0012] Therefore, an object of the present invention is to provide a stripper plate of a progressive die capable of highly accurately performing fine press working of a thin member such as a lead frame which is likely to be deformed during press working. is there.

[0013]

In order to achieve such an object, the present invention is to attach a stripper holder to the upper die side and attach a stripper plate provided with an extraction stage such as a lead frame to the stripper holder. And, in the die for pressing the punching material to be pressed between the lower die and the stripper provided on the upper die side, along the shape of the punch insertion part in the punching stage of the stripper plate. The entire circumference should be formed as a protrusion with a predetermined width, and the region of this protrusion that requires particularly pressing force should be formed as a flat pressing surface, while the other regions should be formed as tapered pressing surfaces. Is characterized by.

[0014]

According to the present invention, in the protrusion-shaped pressing portion of the stripper plate, a region which requires particularly pressing force is formed as a flat pressing surface, and the other regions are formed as tapered pressing surfaces. In particular, this taper-shaped pressing surface can absorb the escape of the pressing force, can efficiently press the portion where deformation easily occurs, and prevent deformation of the press-cut material 10a during press working. To do.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. Since the basic structure of the progressive die used in the present invention is almost the same as that used conventionally, those shown in FIGS. 3 and 4 are incorporated.

That is, the stripper holder 3 is attached to the upper sub 2 on the upper die 1 side of the die, and the stripper plate 4 is attached to the stripper holder 3. As the stripper plate 4, the removal stages 4a are arranged at a predetermined interval, and the stripper plate 4 has a so-called integral structure or a structure close to it as a whole.

Further, on the lower die 5 side, a die plate 8 is provided on a lower sub 6 via a lower packing plate 7 which is a floor plate.
Is installed. Then, between the stripper plate 4 on the side of the upper die 1 and the die plate 8 on the side of the lower die 5 described above, a coiled press-cutting material 10 to be a product as shown by a dotted line in the drawing is provided on the upper die 1 Then, the lower die 5 is inserted from the inlet end to the outlet end (in the direction of the arrow in the figure), and is sequentially fed to perform punching by press working of each punching stage to obtain a finished processed product. Further, 9 is a stripper provided on the upper mold 1, and 9a is a spring for applying a pressing force to the stripper 9.

On the other hand, at the time of press working, as shown in FIG. 4, a punching stage 4a such as a lead frame 10a.
The stripper plate 4 provided with is attached to the stripper holder 3, and the punch 9b is inserted into the punch insertion portion 11 while pressing the punching material 10 inserted between the stripper holder 3 and the lower sub 8 of the lower die 5. It is pressed,
The region of the stripper plate 4 that follows the shape of the punch insertion portion 11 is formed as follows.

Along the shape of the punch insertion portion 11 of the stripper plate 4, the entire circumference of the punch insertion portion 11 has a predetermined width and the protrusion 2 is formed.
0, and the region of the protrusion 20 that particularly requires a pressing force is formed as a flat pressing surface 20a. Further, the other region is formed as a tapered pressing surface 20b to provide a relief surface portion for pressing force.

A specific example of the raised portion 20 will be described. For example, in the case of a lead frame 10a (see FIG. 5) of a circuit of a printed wiring board used in a semiconductor device or the like, the width T1 of the raised portion 20 is 0.5. mm to 1.0 mm, and the inclination angle of the tapered pressing surface 20b is flat.
However, it is preferable to set the step difference θ1 to be about several tens of microns.

Next, the lead frame 10a shown in FIG.
When the press processing is performed in the processing order of
(1) When the entire peripheral surface of the punch insertion part 11 is a flat pressing surface (conventional product), (2) the convex part 20 is provided on the entire peripheral surface of the punch insertion part 11 and the convex part 20 is entirely flat. When used as a pressing surface (conventional product), (3) a protrusion 20 is provided on the entire surface around the punch insertion portion 11, and the protrusion 20 has a tapered pressing surface 20b extending from the tip to 8.0 mm. Table 1 shows a test example in the case where the area (1) is a flat pressing surface 20a (invention product).

The X and Y directions in Table 1 are as described above, the X direction is the warped state when the lead frame 10a is viewed from the longitudinal direction, and the Y direction is the lead frame 10.
As viewed from the thickness direction of a, the upper right portion shows a twisted state (+) and the lower left portion shows a twisted state (-).

[0023]

[Table 1]

As is clear from Table 1, the lead deformation in the present invention is about 1/10 of that in the conventional case.
I have been able to hold back and forth. In the present invention, since the pressing force can be released by the tapered pressing surface 20b, the pressing in the portion H where deformation easily occurs can be efficiently exerted, and the deformation of the lead frame 10a is remarkably improved. Is. Further, since the pressing efficiency is improved, the total pressing is inevitably reduced and the tonnage of the press machine is also reduced.

[0025]

As described above, according to the present invention,
Since the stripper plate of the die for punching thin materials such as lead frames has a relief surface for pressing force as a tapered pressing surface, it is possible to perform fine pressing of thin materials that easily deform during pressing. Can be performed with high precision.

[Brief description of drawings]

FIG. 1 is a plan view showing a punch insertion portion of a stripper plate according to the present invention.

FIG. 2 is a sectional view taken along line I-I in FIG.

FIG. 3 is a schematic cross-sectional view showing the basic structure of a progressive die used conventionally.

FIG. 4 is an explanatory cross-sectional view showing when the die shown in FIG. 3 is pressed.

FIG. 5 is a cross-sectional view showing a specific example of a lead frame.

FIG. 6 is an explanatory diagram showing warpage and twist of the lead frame shown in FIG.

FIG. 7 is an explanatory diagram showing a case where the entire circumference of the punch insertion portion is formed flat.

FIG. 8 is an explanatory diagram showing a case where a protrusion is provided on the entire circumference of the punch insertion portion.

FIG. 9 is an explanatory diagram showing a press working sequence of a lead frame.

[Explanation of symbols]

 4 Stripper plate 4a Extraction stage 11 Punch insertion part 20 Convex part 20a Flat pressing surface 20b Tapered pressing surface

Claims (1)

[Claims] 1. A stripper holder is attached to the upper die side, a stripper plate provided with a stripping stage such as a lead frame is attached to the stripper holder, and a press punching material inserted between the stripper holder and the lower die is used as the upper die. In a die that is pressed by a stripper provided on the side and pressed, the entire circumference is formed as a protrusion with a predetermined width along the shape of the punch insertion portion in the punching stage of the stripper plate, and the protrusion is formed. A stripper plate of a progressive die, characterized in that a region requiring particularly pressing force is formed as a flat pressing surface, and the other regions are formed as tapered pressing surfaces.