JP2744963B2 - Metal plate 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 method for punching a metal sheet material with high precision by using a die and a punch.

[0002]

2. Description of the Related Art As is well known, when a metal plate material is punched by a die and a punch set in a press machine, the cut surface thereof is deformed in a punching direction called a punch sag.
Generally, there is a problem that accuracy and aesthetics are impaired.
(Refer to the enlarged cross-sectional view of FIG. 6).

[0003] Also, there is a so-called fine blanking (finish blanking) method as a method for beautifully blanking with less punching sagging, and although there is a dedicated machine for that purpose, in the conventional fine blanking method, the metal to be blanked out is used. Depending on the shape of the component, the protrusion (corner portion) is likely to be sagged, resulting in inconvenience as a component function. (Refer to the enlarged cross-sectional view of FIG. 7).

[0004] A shaving method for reducing the cutting allowance so as to cut the material is also known as a method for reducing the sagging of the punching. However, the shaving method generally deteriorates the productivity and is similar to the fine blanking method. There is a problem that a shear plane cannot be obtained. (Refer to the enlarged sectional view of FIG. 8).

[0005]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a new method of punching a metal plate without sagging on a cut surface.

[0006]

For this purpose, according to the present invention, when a metal plate material is punched by a die and a punch, the material is formed to have a diameter slightly larger than a hole diameter of a die in advance by a cutting allowance. A surrounding member surrounding the outer peripheral surface of the material is fixed on the die so as to have a slight gap with the upper surface of the die,
When the punch is pressed down, the cutting margin is guided by the inner surface of the surrounding member, and extends as chips into the gap. Further, the present invention is characterized in that in the above-described method for punching a metal plate, the gap is set to be a few percent of the cutting allowance.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a longitudinal sectional view of a main part of a punching die used for the metal plate punching method. In the drawing, reference numeral 1 denotes a die, and 2 denotes a die provided in a hole 3 of the die 1 so as to be movable up and down. The blank holder 4 is a punch having the same diameter as that of the hole 3. The outer diameter of the metal plate material m is previously set to c.
(For example, about 0.3 mm), it is formed to be larger than the inner diameter of the hole 3. When the material m is placed on the hole 3, the surrounding member 6 is attached to the die 1 with a small gap g (for example, 0.2 m) so as to surround the outer peripheral surface of the material m.
m) is fixed on the die 1 via a plate-shaped spacer 7 having a required thickness. The surrounding member 6 is made of material m
The inner side surface 8 is formed in a tapered shape in order to make it easier to load the above into the hole 3 from above. Reference numeral 9 denotes a sleeve slidably covering the outer periphery of the punch 4.

For this reason, when the punch 4 is pressed down and the material m is pushed into the hole 3 of the die 1 and a shear stress is applied to the cut c, the cut c is guided to the inner surface of the surrounding member 6 as shown in FIG. As a result, chips d are drawn into the gap g. Then, by further lowering the punch 4, the chips d are separated from the material m as shown in FIG. 3, and a product p can be obtained. FIG. 4 is a perspective view showing an example of a product p obtained by the punching method, and FIG. 5 is a perspective view showing chips d formed at that time.

The size of the gap g controls the thickness of the chips d thus formed. By adjusting the size of the gap g in accordance with the material and thickness of the material m or the cut c, the shear force applied to the cut c can always be appropriately controlled. In addition, generally, the gap g is smaller than the cutting allowance c and its number is a few percent (usually 70 to 80%).
It is good to do. The surrounding member 6 can prevent the cutting margin c from expanding outward when the punch 4 is pressed down, and can perform punching with less sagging, so that a beautiful and highly accurate product p can be obtained. Needless to say, the outer shape of the product p can be stamped and formed into various shapes other than the illustrated pentagonal shape.

[0010]

As described above, in the method for punching a metal plate according to the present invention, a surrounding member is provided for surrounding the outer peripheral surface of the metal plate material, and a gap is formed between the surrounding member and the upper surface of the die. , The generation of dripping can be extremely reduced and a cut surface by shearing can be obtained, which has a beneficial effect of finishing with high accuracy and beautifulness.

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional view of a die-cutting method of a metal plate punching method according to the present invention.

FIG. 2 is an operation state diagram of FIG. 1;

FIG. 3 is an operation state diagram of FIG. 2;

FIG. 4 is a perspective view showing an example of a punched product according to the present invention.

FIG. 5 is a perspective view showing an example of chips generated when the product shown in FIG. 4 is punched.

FIG. 6 is an enlarged view of a section cut by conventional punching.

FIG. 7 is an enlarged view of a cut surface by a conventional fine blanking method.

FIG. 8 is an enlarged view of a cut surface obtained by a conventional shaving method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Die 3 Drilling hole 4 Punch 6 Surrounding member 7 Dice m Metal plate material g Clearance c Cutting margin d Chip p Product

Claims (2)

(57) [Claims] When a metal plate material is punched by a die and a punch, the material is previously formed to have a diameter slightly larger than a hole diameter of a die by a cutting margin, and a surrounding member surrounding an outer peripheral surface of the material is formed. It is fixed on the die so as to have a slight gap with the upper surface of the die, and when the punch is pressed down, the cut margin is guided by the inner surface of the surrounding member and extends as chips into the gap. A featured metal sheet punching method. 2. The method for punching a metal plate according to claim 1, wherein the gap is set to several percent of the cutting allowance.