JP3271298B2 - Punching method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a punching method for performing shaving after a first punching.

[0002]

2. Description of the Related Art When forming an opening in a metal plate by punching,
When an opening of finished dimensions is formed by one punch,
Since the metal plate has toughness, sagging occurs around the upper surface of the opening. As a method for removing such sagging, an opening smaller than the finished size is formed by the first punching, the opening is processed to the finished size by the second punching, and sagging caused by the first punching is performed. There is a method of removing.

In such a conventional punching method, first, as an example, first, a first press device as shown in FIG. 5A is used. The first press device includes a first punch 1 smaller than a finished dimension and a die 3 having a die hole 2 corresponding to the first punch 1. Then, a metal plate 4 made of a simple substance such as iron, copper, aluminum or the like or an alloy of permalloy or the like is positioned and placed on the upper surface of the die 3, and the first punch 1 is lowered, as shown in FIG. As shown, an opening 5 having a size corresponding to the first punch 1 is formed in the metal plate 4, and a sag 6 is formed around the upper surface of the opening 5. Next, a second press device as shown in FIG. 6A is used. The second press device includes a punch for shaving 7 having a finished size and a die 9 having a die hole 8 having a size substantially equal to the punch 7 for shaving. Then, the metal plate 4 in which the opening 5 is formed is positioned and placed on the upper surface of the die 9, and the punch for shaving 7 is lowered. As shown in FIG. The opening 5 is processed to the finished size, and most of the sag 6 generated by the first punching is removed. In this shaving process, since the shaving allowance is small, no new dripping occurs.

[0004]

However, with such a conventional punching method, it was not possible to completely remove the sag 6 generated by the first punching. For this reason, for example, a finish size of 1.1 mmφ (a first punching size of 0.8 mm) is formed on a metal plate having a thickness of 0.5 mm.
In the case where a plurality of circular openings of φ) are formed and the distance (width) between the openings is considerably reduced to 0.1 mm, for example, the width of the width indicated by reference numeral 10 in FIG. Since the sag 6 generated by the first punching remains on both sides of the upper surface of the portion, there is a problem that the strength of the portion 10 having this small width is considerably reduced. In addition, by making the first punching size smaller, the sag generated by this first punching is prevented from reaching the finished size portion, and by performing shaving processing a plurality of times, the first punching There is also a method of completely removing the generated sagging. However, in this case, it is necessary to prepare a plurality of punching punches for shaving having different dimensions corresponding to a plurality of shaving processes and a plurality of dies having die holes corresponding thereto. In addition to this, there is another problem that the cost of manufacturing the mold is increased and the cost is increased.
An object of the present invention is to completely remove sagging caused by the first punching by one shaving process without performing a plurality of shaving processes using a plurality of shaving punches having different dimensions. An object of the present invention is to provide a punching method that can be performed.

[0005]

SUMMARY OF THE INVENTION According to the present invention, an opening smaller than the finished size is formed in a metal plate using a first punching punch smaller than the finished size, and then the wedge-shaped punch is connected to the metal plate. To form a raised portion around the upper surface of the opening, and then press the flattening punch against the raised portion around the upper surface of the opening of the metal plate to flatten the raised portion by crushing. By doing so, the sag formed around the upper surface of the opening of the metal plate is removed by punching with the first punching punch, and then the shaving punch having a finished size is used. The opening of the metal plate is processed to a finished size.

[0006]

According to the present invention, after the first punching, a step of forming a raised portion with a wedge-shaped punch and a step of crushing the raised portion with a flattening punch are performed.
Since the periphery of the upper surface of the opening of the metal plate after the second punching is flattened, sagging caused by the first punching can be completely removed, so that a plurality of shaving punches having different dimensions are used. The sagging caused by the first punching can be completely removed by one shaving process without performing the shaving process a plurality of times, that is, the sagging can be completely removed at low cost.

[0007]

1 to 4 show the respective working steps of a punching method according to an embodiment of the present invention. A punching method for performing shaving after the first punching will be described with reference to these drawings.

First, a first press as shown in FIG. 1A is used. This first press device is shown in FIG.
And a die 23 having a die hole 22 corresponding to the first punch 21 which is smaller than the finished size and is smaller than the finished size. Then, a metal plate 24 made of a simple substance such as iron, copper, aluminum or the like or an alloy such as permalloy is placed on the die 2.
When the first punch 21 is lowered and positioned on the upper surface of the third punch 3, the opening having a size corresponding to the first punch 21 is formed in the metal plate 24 as shown in FIG. 25 are formed, and a sag 26 is formed around the upper surface of the opening 25.

Next, a second pressing device as shown in FIG. 2A is used. The second press includes a wedge-shaped punch 27 and a die 28 having a flat upper surface. The angle of inclination θ of the tip of the wedge-shaped punch 27 is about 30 to 45 °, and the size of the lower end surface of the tip inclined portion is smaller than the opening 25 of the metal plate 24. The size of the upper end is larger than the opening 25 of the metal plate 24. Then, the metal plate 24 in which the opening 25 is formed is positioned and placed on the upper surface of the die 28, and the wedge-shaped punch 27 is lowered, as shown in FIG.
The leading end of the wedge-shaped punch 27 is connected to the opening 25 of the metal plate 24.
When the metal plate 24 is pressed into the metal plate 24 to a depth corresponding to about 50 to 70% of the thickness of the metal plate 24, the upper portion of the inner wall of the opening 25 rises around the upper surface of the opening 25 to form a bulge 29. You.

Next, a third pressing device as shown in FIG. 3A is used. The third pressing device includes a flattening punch 30 having a flat lower surface, and a die 31 having a flat upper surface. Then, the raised portion 2 is formed around the upper surface of the opening 25.
When the metal plate 24 on which the metal 9 is formed is positioned and placed on the upper surface of the die 31, and the flattening punch 30 is lowered, FIG.
As shown in (B), the lower surface of the flattening punch 30 is pressed against the raised portion 29 around the upper surface of the opening 25 of the metal plate 24. As a result, the raised portion 29 is crushed to be flush with the upper surface of the metal plate 24. The protrusion 25 is flattened, and a slight protrusion 32 is formed on the inner wall of the opening 25. Therefore, in this state, the sagging 26 generated by the first punching is completely removed.

Next, a fourth pressing device as shown in FIG. 4A is used. FIG. 6A shows the fourth press device.
And a punch 35 for shaving having a finished size and a die 35 having a die hole 34 substantially the same size as the punch 33 for shaving. Then, the metal plate 24 having the upper surface of the opening 25 flattened is placed on the die 3.
When the punching punch 33 for shaving is lowered and positioned on the upper surface of the metal sheet 5, the opening 25 of the metal plate 24 is machined to a finished size as shown in FIG. In this case, as shown in FIG. 4 (A), even if the protrusion 32 is formed on the upper part of the inner wall of the opening 25 of the metal plate 24, the amount of formation of the protrusion 32 is small. The shaving allowance at the time does not become so large, and no new dripping occurs.

As described above, in this punching method, 1
After the first punching, a step of forming the raised portion 29 by the wedge-shaped punch 27 and a step of crushing the raised portion 29 by the flattening punch 30 are performed to flatten the periphery of the upper surface of the opening 25 of the metal plate 24 after the first punching. As a result, the dripping 26 generated by the first punching can be completely removed. Therefore, even if the shaving is performed once, the dripping 26 generated by the first punching is performed.
6 can be completely removed. As a result, for example, a metal plate having a thickness of 0.5 mm is formed with a plurality of circular openings having a finished size of 1.1 mmφ (the first punching size is 0.8 mmφ), and the intervals between the openings are small. Even when the width is made as small as 0.1 mm, for example, the entire upper surface of the widened portion indicated by reference numeral 36 in FIG. 4B can be flattened, so that the strength of the widened portion 36 decreases. Can not be.

[0013]

As described above, according to the present invention, the periphery of the upper surface of the opening of the metal plate after the first punching is flattened to completely remove sagging caused by the first punching. Therefore, without performing a plurality of shaving processes using a plurality of shaving punches having different dimensions, it is possible to completely remove sagging caused by the first punching by one shaving process,
That is, the dripping can be completely removed at low cost.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view showing a state before processing by a first press device in a punching method according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view showing a state after the processing.

FIG. 2 is a cross-sectional view showing a state before processing by a second press device in the punching method, and FIG. 2 (B) is a cross-sectional view showing a state after the processing.

FIG. 3 is a cross-sectional view showing a state before processing by a third press device in the punching method, and FIG. 3 (B) is a cross-sectional view showing a state after the processing.

FIG. 4 is a cross-sectional view showing a state before processing by a fourth press device in the punching method, and FIG. 4B is a cross-sectional view showing a state after the processing.

FIG. 5 is a cross-sectional view showing a state before processing by a first press device in a conventional punching method, and FIG. 5B is a cross-sectional view showing a state after the processing.

FIG. 6 is a cross-sectional view showing a state before processing by a second press device in the conventional punching method, and FIG. 6B is a cross-sectional view showing a state after the processing.

[Explanation of symbols]

 Reference Signs List 21 punching punch for first time 24 metal plate 25 opening 26 sag 27 wedge-shaped punch 29 swelling portion 30 flattening punch 33 punching punch for shaving

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B21D 28/00-28/36 B21D 31/00-35/00

Claims (1)

(57) [Claims] After forming an opening smaller than the finished size in a metal plate using a first-time punched punch smaller than the finished size, a wedge-shaped punch is pushed into the opening of the metal plate to form the opening. By forming a raised portion around the upper surface of the opening, and then pressing a flattening punch against the raised portion around the upper surface of the opening of the metal plate to flatten the raised portion by crushing,
The sagging formed around the upper surface of the opening of the metal plate is removed by punching with a punching punch for the second time, and then the opening of the metal plate is punched using a shaving punch having a finished size. A punching method characterized by processing to a finished dimension.