JP2000158059A - Scrap floating prevention die device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a die device capable of surely preventing scrap floating in punching without having rough face working as well as taperd shape forming of a die hole. SOLUTION: In a continuous die device in which a material to be worked is held to a die side with a stripper and is punched by a punch, in the front of the punching place where the material 2 is punched by the punch 1 and a die hole 4, a recess forming punch 7, which is arranged with a protrusion 8 to form a recess 10 to a planned punching place of the material 2 to be worked, is arranged, a planned punching place, including the recess 10 formed to the material 2 to be worked by the recess forming punch 7, is punched by reciprocating the punch 1 into the die hole 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold device for preventing scumming.

[0002]

2. Description of the Related Art In a punching die apparatus, a workpiece is pressed against a die by a stripper and fixed, and a punch is advanced and retracted into a die hole to perform punching. Semiconductor device parts such as lead frames and iron core pieces, or electrical equipment parts are manufactured with such a mold apparatus.

[0003] During the punching process, the punched residue may not stay in the die hole or fall below the die hole, and a phenomenon that the punch rises upward from the die hole may occur.

[0004] The scumming causes dents on the product,
When dents are formed, the commercial value of the product is impaired and the product becomes defective. Further, when the scumming is severe, two sheets are punched out and the punches and dies are damaged, so that it takes time and effort to remove, repair, and reattach the punches and dies, thereby lowering productivity.

[0005] Conventionally, proposals have been made for prevention of blurring. For example, a method in which the inner peripheral surface of the die hole is roughened to increase the contact force with the punched swarf so that the scum does not protrude above the die hole, or the inner peripheral surface of the die hole is formed in an upward tapered shape. Then, there is a method of preventing the punching residue from going above the die hole. Each of these techniques has a corresponding effect.

[0006]

However, in the punching operation using a die apparatus, it is necessary to re-grind the punch and die holes so that the product does not have large burrs or sagging. Each time the die hole must be roughened or taped, the processing operation becomes complicated.

[0007] In fact, it cannot be said that prevention of scumming is sufficiently achieved. SUMMARY OF THE INVENTION An object of the present invention is to provide a mold apparatus capable of reliably preventing scumming without performing a complicated punch or die hole machining operation.

[0008]

The gist of the present invention to achieve the above object is to provide a progressive die apparatus in which a projection for forming a dent in a portion to be punched is provided in front of a punch and die holes to be punched. The present invention is directed to a mold for preventing scum from rising, wherein a dent forming punch is provided, and a region including a dent formed by the dent forming punch is punched by the punch and a die hole.

[0009]

Next, an embodiment of the present invention will be described with reference to the drawings. In the drawing, reference numeral 1 denotes a punch which punches a workpiece 2 which is fed forward into and out of a die hole 4 provided in a die 3.

Reference numeral 5 denotes a stripper which presses and fixes the workpiece 2 against the die 3 when punching the workpiece 2, and guides the punch 1 to the die hole 4 through a punch guide hole 6 formed.

Reference numeral 7 denotes a dent forming punch for forming a dent at a portion of the workpiece 2 to be punched, and a small projection 8 is provided at the tip. The dent forming punch 7 is installed at an integral multiple of the forward feed interval in front of the location where the punch 1 for punching the workpiece 2 and the die hole 4 are installed. That is, as in this embodiment, the punch 1 and the die hole 4 to be punched may be installed immediately before the forward feeding, or may be installed further forward. In FIG. 1, a set of punches 1, a die hole 4, and a recess forming punch 7 are shown.
Although only shown, a suitable number can be provided in order to form the above-mentioned dents in a portion where a punching width is apt to occur and a small punching portion.

The depression forming punch 7 may be formed as a projection 8 so as to have a length along the punched portion 9 as shown in FIG. 2A or a single projection as shown in FIG. May be the mountain-shaped projection 8. Further, the cross-sectional shape of the projection 8 is a V shape shown in FIG. 3A, a square shape shown in FIG. 3B, a trapezoidal shape shown in FIG. 3C, a U shape shown in FIG. 3D, or a hemispherical shape as shown in FIG. Is done.

The surface of the die 3 facing the recess forming punch 7 is flat like other surfaces, but may be minutely recessed if necessary.

The configuration of the present invention is as described above, and then the operation will be described. The workpiece 2 which has been fed forward is pressed against the die 3 by the stripper 5, and the recess forming punch 7 is advanced and retracted at the portion of the workpiece 2 to be punched to form the recess 10. The depth of the recess 10 is about 0.01 to 0.20 mm, and its width is about 0.01 to 0.30 mm.

Next, the stripper 5 is retracted from the surface of the die 3, and the workpiece 2 is fed forward so that the portion to be punched comes over the die hole 4. The workpiece 2 is stripped by a stripper 5 into a die 3.
The punch 1 is pressed against the surface and advanced to the die hole 4 for punching.

When the dent 10 is formed at the place to be punched by the dent forming punch 7 provided with the projection 8 as described above, a minute dent is locally formed and a stress remains near the dent. When the portion including the recess 10 is punched, the punch residue 11
As shown in (1), when pulled down into the die hole 4, the lower side of the lower side is expanded and strongly contacts the inner surface of the die hole 4, so that it does not rise.

[0017]

According to the present invention, before the punch is advanced to and retracted from the die hole and the workpiece is punched as described above, a dent forming punch for dentting a portion to be punched is provided, and the dent is formed by the dent forming punch. When punching is performed by a punch and a die hole including a portion, the punched chips slightly warp in the die hole, and the contact force with the inner surface of the die hole increases. Therefore, even if the chippings are fine, they do not go up, there are no dents and no punching, and a punched product of excellent quality can be obtained. Further, the punch and die are not damaged and the productivity is low. And the like.

[Brief description of the drawings]

FIG. 1 is a diagram showing a mold device for preventing scumming up in one embodiment of the present invention.

FIG. 2 is a plan view of a tip of a dent forming punch provided with a protrusion according to the present invention.

FIG. 3 is a view showing various shapes of projections provided on a depression forming punch in the present invention.

FIG. 4 is a view for explaining the scumming prevention action in one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Punch 2 Work material 3 Die 4 Die hole 5 Stripper 6 Punch guide hole 7 Depression forming punch 8 Projection 9 Punching part 10 Depression 11 Punching residue

Claims (3)

[Claims] 1. A progressive die apparatus for punching a workpiece with a holding punch on a die side with a stripper on a die side, wherein a dent is formed at a position to be punched in the workpiece before punching the workpiece with a punch and a die hole. Provide a dent forming punch with a projection to attach,
A lift-up preventing die apparatus, characterized in that a punching expected portion including a dent formed in a workpiece by the dent forming punch is punched by moving the punch into and out of a die hole. 2. The scum-prevention die apparatus according to claim 1, wherein the projection provided on the dent forming punch is a projection having a length in a predetermined punching direction or a single mountain-shaped projection. . 3. A projection provided on the recess forming punch,
2. The scum-prevention mold apparatus according to claim 1, wherein the mold apparatus has a shape of a square, a trapezoid, a U, or a hemisphere.