JPS62259625A - Blanking method for metal sheet - Google Patents

Abstract

PURPOSE:To prevent occurrence of burrs on the surface of blanked products by forming a part to be blanked of a metal sheet with a slit punch and blanking the part after the part is coined with a coining punch. CONSTITUTION:A part to be blanked 10 is formed on a metal sheet 6 with a slit punch 7 for blanking of rotor plates, etc. of a variable capacitor. Then, a coining punch 8 coins only the outer edge of the part 10 to form a coined part 11. A punch 9 blanks the part 11 to form a required shape. In the above case, the coined part is relatively thined than other parts. Therefore, good products without burrs are formed because a coined section part is formed in the blanking work.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for punching a metal plate, and more particularly to a method for punching a punched member in which no burr is generated in the punched portion of the punched member.

[Conventional technology]

The conventional method for punching out metal plates will be explained using the case of processing the rotor plate of a variable capacitor as an example. Figure 4 schematically shows the punched portion of the rotor plate punched using the conventional method. . Conventionally, a metal plate was punched out in one go using a punch, so burrs 3 were usually formed on the upper surface of the fractured surface 2 as shown in the figure. Note that 4 is a sheared surface formed below the fracture surface 2, and 5 is a sag formed below the sheared surface 4.

[Problem that the invention seeks to solve]

When the rotor plate 1 as described above is used in a variable capacitor that uses a plastic film as a dielectric, the burrs 3 damage the film as the rotor plate 1 rotates, causing the rotor plate 1 to come into contact with the stator plate. There was a problem that electrical conduction occurred.

The invention is based on the above-mentioned problems, and its purpose is to provide a punching method that does not cause burr on the surface of the punched product when punching a metal plate with a die. .

[Means for solving problems]

In order to achieve the above object, the invention includes a first step of forming punched portions of a desired shape and a decoy shape on a metal plate using a slit punch, and a desired shape portion formed by the first step. The method is characterized by comprising a second step of forming a coined seal, and a third step of punching out parts other than the desired shape portion coined in the second step with a punch.

[Effect]

In the present invention, by coining the outer periphery of the desired shape part in the second step, the coined part becomes thinner than the other parts. Therefore, this thinned part is
By punching in the process, coined cross-sections are formed on both sides of the punched member, so there is no occurrence of burrs.

〔Example〕

Hereinafter, the present invention will be explained in detail using the drawings.

FIGS. 1(a) and 3(b), FIGS. 2 and 3 show an embodiment of the present invention, and FIG. 1(a) is a plan view showing the punching process of a rotor plate of a variable capacitor. FIG. 2 is a side view of the rotor plate, and FIG. 3 is a side view of the rotor plate and coining punch during coining.

W; In Figure 1, 6 is a hoop-shaped thin metal plate, 7 is a slit punch provided in the mold, 8 is a coining punch, and 9 is a punch. The thin metal plate 6 is sequentially conveyed and processed from left to right in FIG. 1(A).

First, as a first step, as shown in the left part of FIG. 1(b), a punched portion 10 having the same shape as the rotor plate is punched out using a slit punch 7.

Next, in a second step, only the outer peripheral portion of the desired shape portion 13 formed in the first step is coined using a coining punch 8 to form a coined portion 11 (FIG. 3). The shape of the coined portion 11 formed in this second step is thinner than the uncoined portion as shown in FIG. 2, and is referred to as a so-called coined cross-sectional shape 14. The size of the coining punch cross-sectional shape 12 of the coining punch 8 that forms the coining cross-sectional shape 14 varies depending on the thickness t of the metal plate 1, but is always formed to an appropriate size. Slits formed in the first step) 1
0 is the achievement moving part 1 of the coining part 11 formed in the second process
6 and shape it.

Next, the thin metal plate 6 is conveyed to a punch 9 and, as a third step, is punched out by the punch 9 having the shape of the coining part 11, as shown in the right part of FIG. 1(b).

Since the coined cross-sectional shape 14 created by the coining punch 81 is formed on both sides of the rotor plate 1 punched out as described above, the burr 3 does not occur on the surface as seen in the conventional example. .

Therefore, even if such a rotor plate 1 is used in a variable capacitor that uses a plastic film as a dielectric, the rotor plate 1 will not be damaged because there are no holes 3 on both sides of the rotor plate 1. Accidents such as short-circuiting between the terminal and the stator plate will not occur.

The metal plate punching method of the present invention is not limited to rotor plates of variable capacitors, but can be applied to all products in which it is a problem to have holes protruding from the surface of the punched product.

〔effect〕

As described above, the method of the present invention includes the first step of punching a metal plate using a slit punch, and the second step of stamping the desired shape part punched in the first step.
and a third step of punching out the parts and shapes stamped in the second step with a punch,
Since no cracks are produced on the surfaces of both sides of the punched product, for example, when this punching method is used for punching the rotor plate or stator plate of a variable capacitor that uses plastic film as a dielectric, both of the frame plates are Since there is no possibility of formation of flakes on the surfaces of both surfaces and there is no possibility of damaging the film, it has the effect of avoiding the inconvenience of electrical conduction between the two electrode plates.

[Brief explanation of drawings]

FIGS. 1(a) and 3(b) show an embodiment of the present invention, and FIG. b) is a front view showing the same punching process, Fig. 2 is a side view of the rotor plate, Fig. 3 is a front view showing the coining process, and Fig. 4 is a conventional punching method l.
A side view of the rotor feed plate thus manufactured is shown. 1... Rotor plate 6... Metal plate 7... Slit punch 8... Coining punch 9... Punch punch 10... Slit portion 11... Coining portion Patent applicant Alps Electric Co., Ltd. Representative Masaru Kataoka Figure 1 (a) (b)

Claims (1)

[Claims] A first step of forming a punched portion of the same shape as a desired shape on a metal plate using a slit punch; a second step of coining the desired shape portion punched in the first step; A method for punching out a metal plate, comprising a third step of punching out the desired shape portion coined in the step with a punch.