JP2701792B2 - Burrless drilling 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 boring a plate material using an NC turret punch, and more particularly to a method for boring without burrs generated by boring.

[0002]

2. Description of the Related Art In a first example of a conventional method of punching a hole using an NC turret punch, the punching is performed in one step by using a pair of dies including a punch and a die.

Japanese Patent Application Laid-Open No. Sho 63-63 is cited as a second conventional example.
Japanese Patent Application Publication No. 76230 discloses a method in which two sets of molds are used to perform punching in two steps, in which half punching and tapered coining are simultaneously performed, and then holes are punched from the half punched recess side. A method has been proposed.

[0004]

However, in the above-described one-step punching process using a punch and a die in the first conventional example, when the punch is pushed into the plate material, the hole cutout portion of the plate material becomes a die side surface. Since a crack is generated slightly below the cutting edge and breaks, burrs always occur on the die side of the hole cutout. Since the burrs are sharp and dangerous, there is a problem that the burrs must be removed by a deburring machine or the like after the punching process.

In the method of performing half blanking and tapered coining as described in the second prior art at the same time and then punching a hole from the half blanked concave side, the scrap is removed when scrap is removed. Rubs on the side of the hole cut, so that rubbing occurs on the die side of the hole cut. Therefore, there was a problem that burrs had to be removed after the punching process.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional circumstances, and accordingly, an object of the present invention is to provide a new burring-free boring process capable of solving the above-mentioned problems inherent in the prior art. It is to provide a method.

[0007]

In order to achieve the above object, a punching method according to the present invention comprises two steps of punching. First, in a first step, a convex portion is formed on an upper side of a plate material. Half-blanking processing. Next, in the second step, the half-removed convex portion is pushed into the plate material by the stripper of the mold,
Punching is performed to discharge the scrap to the die side by punching. In this case, in the half-punched shape in the first step, the cross-sectional shape of the convex portion is straight, the cross-sectional shape of the concave portion is such that the upper diameter of the concave portion is the same as the diameter of the convex portion, and the lower diameter of the concave portion is larger than the convex portion diameter by a certain amount. It has a tapered shape. The diameter of the punch in the second step is smaller by a certain amount than the diameter of the half-hole, and the diameter of the die is larger by a certain amount than the diameter of the lower side of the half-hole.

[0008]

In the present invention, in the first step, the half-punching process is performed so that the convex portion is on the upper side of the plate material. Can be prevented from getting stuck on the die. In the second step, since the half-blanking projection is pushed by the stripper of the mold, the half-blanking connecting portion is sheared, so that no burrs are generated. Since the punch simply pushes the scrap down, the punch diameter can be made smaller than the half-opening convex part diameter, and the die hole diameter is made a certain amount larger than the half-opening concave part lower side. The scrap can be easily pushed down even if a slight displacement occurs between the mold and the half-punched portion in the process. further,
Since the cross-sectional shape of the half-blanked concave portion is tapered, no step is formed on the cut surface of the hole after punching, and scraping due to scrap does not occur.

[0009]

Next, a preferred embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view showing a working state for explaining an embodiment of the working method according to the present invention.
(A) shows the processing state of the half blanking processing, and FIGS. 1 (b) and (c).
FIG. 3 is a cross-sectional view showing a processing state of the punching processing. FIG. 2 is a cross-sectional view of the half blanked portion after the half blanking process.

Referring to FIG. 1, a working method according to the present invention first comprises, as shown in FIG. 1 (a), a half punching die 1 having a tapered tip and a straight die hole 2 having a straight die hole 2. 3, the half blanking process is performed so that the half blanking convex portion 4 is on the upper side of the plate material 5.

Next, a punching process shown in FIGS. 1B and 1C is performed. In FIG. 1 (b), a mold stripper 6 is provided.
As a result, the half blanking convex portion 4 is pushed into the plate member 5. As a result, the half punched connecting portion 7 is sheared. By this step, the portion of the half blanking connection portion 7 of the plate material 5 is drawn inward, so that generation of burrs is avoided. Then, as shown in FIG. 1 (c), the half blanking convex portion 4 becomes a scrap 9 by the punch 8 and is pushed down to the die 10 side. At this time,
The punch diameter 11 is smaller by a certain amount than the half punching convex portion diameter 12, and the die hole diameter 13 is larger by a certain amount than the half punching concave portion lower side diameter 14.

FIG. 2 shows the cross-sectional shape of the plate 5 obtained by the half blanking process. In FIG. 2, the cross-sectional shape of the half-punched convex portion 4 is straight, and the cross-sectional shape of the half-punched concave portion 15
And the lower diameter 17 of the half-recessed concave portion is larger than the diameter 12 of the half-removed 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 stripper 6 of the die in the punching process. The amount is 70 to 80% of the plate thickness.

As another embodiment of the present invention, a semi-punched punch having a straight tip rather than a tapered tip, that is, the upper half-recessed recessed diameter 16 and the lower semi-recessed recessed diameter 17 of FIG. It is envisaged that the half punched concave portions 16 and 17 are formed using a half punched punch formed with a diameter larger than the half punched convex portion diameter 12.

[0016]

As described above, according to the present invention,
The punching is composed of two steps. First, a half punching process is performed on the upper side in a first step, and then, in a second step, the half punching convex portion is pushed in by a stripper of a mold to form a half punching connection portion. , And scraps are pushed down, so that the NC turret punch can be used for punching without generating burrs, and the effect of eliminating the need for deburring work in a later step is obtained.

According to the present invention, it is also possible to form a hole without burrs by using a simple punching die and a half punching die having a simple mold structure, and it is also possible to pull out scraps. The present invention can be applied to a punching machine, and can perform a highly productive, flashless punching process.

[Brief description of the drawings]

FIGS. 1A to 1C are cross-sectional views showing a processing 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]

 DESCRIPTION OF SYMBOLS 1 ... Half punch 2 ... Die hole 3 ... Half punch die 4 ... Half punch convex part 5 ... Plate material 6 ... Die stripper 7 ... Half punch connection part 8 ... Punch 9 ... Scrap 10 ... Die 11 ... Punch diameter 12 ... Semi-opening convex part diameter 13 ... Die hole diameter 14 ... Semi-opening concave lower part diameter 15 ... Semi-opening concave part 16 ... Semi-opening concave part upper part 17 ... Semi-opening concave lower part 18 ... Semi-opening amount

Claims (5)

(57) [Claims] In a punching process of a plate material by an NC turret punch press, a half-punching process is performed so that a convex portion is on an upper side of the plate material. A flash-free punching method characterized by performing punching in which pressing and discharging of scrap to a die side by a punch are performed in one step. 2. The half-blanking process is such that the cross-sectional shape of the convex portion is straight, the cross-sectional shape of the concave portion is such that the upper diameter of the concave portion is the same as the diameter of the convex portion, and the lower diameter of the concave portion is larger than the diameter of the convex portion. The method according to claim 1, further comprising forming a tapered shape. 3. The punching process according to claim 1, wherein the diameter of the punch for discharging the scrap is made smaller than the diameter of the half-punched convex part, and the diameter of the die hole is made larger than the diameter of the half-punched concave part. Item 7. A method for boring without burrs according to Item 1. 4. The half-blanking process is performed in such a manner that the cross-sectional shape of the convex portion is straight, the cross-sectional shape of the concave portion is such that the concave portion upper diameter is larger than the convex portion diameter, and the concave portion lower diameter is the concave upper portion diameter. 2. The method according to claim 1, further comprising the step of forming the same size as the above and making it straight. 5. The method according to claim 1, wherein, in the half blanking, a half blanking amount is set to an amount of 70 to 80% of a thickness of the plate material.