JPH08336798A - Punching method without generating burr - Google Patents

Abstract

PURPOSE: To perform punching without generating a burr by an NC turret punch by performing the pressing of a half-blanking protruding part into a plate by a die stripper and the discharge of a scrap onto the die side by a punch in a single process. CONSTITUTION: A half-blanking protruding part 4 is pushed into a plate 5 by a half-blanking punch 1 with the tapered tip and a half-blanking die 3 with a straight die hole 2. A half-blanked connection part 7 is thereby sheared. With this process, the half-blanked connection part 7 part of the plate 5 is pulled inside so as to avoid the generation of a burr, and the half-blanking protruding part 4 is pushed down as a scrap 9 onto the die 10 side by a punch 8. At this time, a punch diameter 11 is made smaller by a fixed quantity than a half- blanking protruding part diameter 12, and a die hole diameter 13 is made larger by a fixed quantity than a half-blanking recessed part lower side diameter 14.

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 plate material by an NC turret punch, and more particularly to a flashless punching method which does not generate burrs caused by punching.

[0002]

2. Description of the Related Art In a first example of a conventional punching method using an NC turret punch, one punch and a die are used in one step.

As a second conventional example, Japanese Unexamined Patent Publication No. 63-63
In Japanese Patent Laid-Open No. 76230, as a method of punching in two steps using two sets of molds, half punching and tapered coining are performed at the same time, and then a hole is punched from the half punched concave side. A method has been proposed.

[0004]

However, in the one-step punching process using the punch and die in the above-mentioned first conventional example, when the punch is pushed into the plate material, the hole cut portion of the plate material is formed on the side surface of the die. Since a crack is generated from a little below the cutting edge of and breaks, there is always a flash on the die side of the hole cutting part. Since this flash is sharp and dangerous, there is a problem that the flash must be removed by a deburring machine or the like after punching.

Further, in the method of performing the half blanking and the tapered coining at the same time as shown in the above-mentioned second prior art, and then punching the hole from the half blank recess side, when scrap is removed, the scrap is removed. Scrubs the side surface of the hole cutting edge, so rubbing occurs on the die side of the hole cutting edge. Therefore, there is a problem that the flash must be removed after the punching process.

The present invention has been made in view of the above-mentioned conventional circumstances. Therefore, the object of the present invention is to provide a novel burring-free punching process capable of solving the above-mentioned problems inherent in the prior art. To provide a method.

[0007]

In order to achieve the above object, the punching method according to the present invention comprises punching in two steps. First, in the first step, the convex portion is on the upper side of the plate material. Half blanking process. Next, in the second step, the half-punch convex portion is pushed into the plate material by the stripper of the mold,
Perform punching process to discharge scraps to the die side by punching. In this case, the half blanking shape in the first step has a straight cross-sectional shape of the convex portion, the cross-sectional shape of the concave portion has the concave upper diameter equal to the convex diameter, and the concave lower diameter larger than the convex diameter by a certain amount. It has a tapered shape. The punch diameter in the second step is made smaller than the diameter of the half-cut convex portion by a certain amount, and the die diameter is made larger by a certain amount than the diameter of the lower side of the half-drawn concave portion.

[0008]

According to the present invention, in the first step, since the convex portion is half-cut so that the convex portion is on the upper side of the plate material, when the NC turret punch moves the die and the plate material, the half-extruded convex portion is moved. It is possible to prevent the trouble of being caught by the die. In the second step, since the half-blanked convex portion is pushed in by the stripper of the mold, the half-blanked connecting portion is sheared, so that burrs do not occur. Since the punch simply pushes down scrap, the punch diameter can be made smaller than the half punched convex portion diameter, and the die hole diameter is made larger than the half punched concave portion lower diameter by a certain amount. Even if there is a slight misalignment between the die and the half blanking part in the process, scrap can be easily pushed down. further,
Since the cross-sectional shape of the half-depressed recess is tapered, no step is formed on the hole cutting surface after the punching process, and scraping due to scrap does not occur.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described in detail with reference to the accompanying drawings with reference to the accompanying drawings.

FIG. 1 is a sectional view showing a processing state for explaining one embodiment of the processing method according to the present invention.
FIG. 1A shows a processing state of half blanking, and FIG.
[Fig. 3] is a cross-sectional view showing a processing state of punching. FIG. 2 is a cross-sectional view of the half-cut portion after the half-cut processing.

Referring to FIG. 1, in the processing method according to the present invention, first, as shown in FIG. 1A, a half-punching punch 1 having a tapered tip and a half-punching die having a straight die hole 2 are provided. With 3, the half blanking process is performed so that the half blanking convex portion 4 is located above the plate material 5.

Next, the punching process shown in FIGS. 1B and 1C is performed. In FIG. 1B, the mold stripper 6
The semi-blanked protrusion 4 is pushed into the plate member 5 by. As a result, the half-blanked connecting portion 7 is sheared. By this step, the half-blanked connecting portion 7 of the plate member 5 is pulled inward, so that the occurrence of flash is avoided. Then, as shown in FIG. 1 (c), the punch 8 causes the half-blanked convex portion 4 to become scrap 9 and to be pushed down to the die 10 side. At this time,
The punch diameter 11 is made smaller than the diameter 12 of the half-cut convex portion by a certain amount, and the diameter 13 of the die hole is made larger than the diameter 14 at the lower side of the half-thickness concave portion by a certain amount.

The sectional shape of the plate member 5 obtained by the half blanking is shown in FIG. In FIG. 2, the cross-sectional shape of the half-drawing convex portion 4 is straight, and the cross-sectional shape of the half-drawing concave portion 15 is the half-drawing concave portion upper diameter 16 to the half-drawing convex portion diameter 12.
The same size is used, and the lower diameter 17 of the half-cut concave portion is made larger than the diameter 12 of the half-cut convex portion by a certain amount.

Further, the half blanking amount 18 is set so that the half blanking connecting portion 7 is easily sheared by pushing the half blanking convex portion 4 by the die stripper 6 in the punching process. The amount is 70 to 80% of the plate thickness.

As another embodiment of the present invention, a half-punched punch whose tip is formed straight instead of being tapered, that is, the upper diameter 16 of the half-cut recess and the lower diameter 17 of the half-cut recess in FIG. 2 are the same, It is envisioned that a method of using a half-punch punch in which the half-punch recess diameters 16 and 17 are formed larger than the half-push convex diameter 12.

[0016]

As described above, according to the present invention,
The hole punching consists of two steps. First, in the first step, half punching is performed on the upper side, and then in the second step, the half punching convex portion is pushed in by the stripper of the mold, so that the half punching connecting portion is formed. Since the scrap is pushed down by shearing, the NC turret punch can be used for punching without burrs, and the deburring work in the subsequent process becomes unnecessary.

Further, according to the present invention, since the semi-blank die and the punch die having a simple die structure can be used for burring without burrs and scraps can be removed, automatic NC turret punch and the like can be easily performed. It can be applied to a punching machine and can perform flashless punching with high productivity.

[Brief description of drawings]

1A to 1C are cross-sectional views showing a processed state for explaining an embodiment of the present invention.

FIG. 2 is a sectional view showing a sectional shape obtained by half blanking.

[Explanation of symbols]

 1 ... Half-punch punch 2 ... Die hole 3 ... Half-punch die 4 ... Half-punch convex portion 5 ... Plate material 6 ... Mold stripper 7 ... Half-pull connecting portion 8 ... Punch 9 ... Scrap 10 ... Die 11 ... Punch diameter 12 ... Half-drawing convex part diameter 13 ... Die hole diameter 14 ... Half-drawing concave part lower diameter 15 ... Half-drawing concave part 16 ... Half-drawing concave upper part 17 ... Half-drawing concave part lower-diameter 18 ... Half-drawing amount

Claims (5)

[Claims] 1. A hole punching process of a plate material by an NC turret punch press is performed so that a convex portion is on an upper side of the plate material, and then a half-cut convex portion of the die is stripped into the plate material. A burring-free punching method characterized by carrying out punching in one step of pushing and discharging scraps to the die side by punching. 2. The processing shape of the half blanking is such that the convex cross section is straight, and the concave cross section has a concave upper diameter equal to the convex diameter and a concave lower diameter larger than the convex diameter. The method for punching without flash according to claim 1, further characterized by being formed into a tapered shape. 3. In the punching process, the punch diameter for discharging the scrap is set smaller than the diameter of the half-cut convex portion, and the die hole diameter is set larger than the lower diameter of the half-cut concave portion. The method for punching without flash according to Item 1. 4. The processing shape of the half blanking is such that the convex cross-sectional shape is straight, the concave cross-sectional shape is such that the concave upper diameter is larger than the convex diameter, and the concave lower diameter is the concave upper diameter. The burrless hole punching method according to claim 1, further characterized in that the same dimension as that is straightened. 5. The flashless hole punching method according to claim 1, further comprising setting the half punching amount to 70 to 80% of the plate thickness of the plate material in the half punching process.