JPH0665442B2 - Cutting method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a cutting method in which sharp burrs, ie, burrs and corners do not occur at the edge of a cut portion of a metal plate.

(Prior Art) Cutting of a metal plate is usually performed by a shearing device,
Sharp burrs are easily formed on the edge of the sheared portion. When the burr is formed, it not only interferes with the subsequent steps, but also when the coating is performed in the subsequent step, the coating material adheres in a bead shape and sags, resulting in poor coating.

In order to avoid this inconvenience, it is general to remove the burr by hand, but since it is a labor-intensive work, in JP-A-55-103235, 57-184617, etc., while preventing the occurrence of burr, A method of cutting is proposed. In this method, upper and lower punches having a V-shaped cross-section top and bottom are formed by pressing the cutting position of the work to form V-shaped grooves on the upper and lower sides, and then the thin-walled portion between the groove bottoms is sheared and separated. is there.
When this method is used, the upper and lower surfaces of the work are pushed toward the center by the punch, so that there is an advantage that the edge does not have outward burr.

(Problems to be solved by the invention) When the above means is used, the work does not burr and the edge becomes an obtuse angle, but since the corner of the edge has no roundness, the paint easily gathers at the time of coating, and the paint drips. Is inevitable.

Therefore, an object of the present invention is to obtain a cutting method that does not cause such inconvenience.

(Means for Solving the Problem) The problem to be solved by the present invention is to perform a first step of pressing a cutting position of a work with upper and lower punches to form a thin portion, and to form the thin portion at a boundary between the thin portion and a product side. In a cutting method comprising a second step of cutting, a punch used in the first step is provided with an end surface protruding therefrom and a side surface continuing from the end surface, and at least the base of the side surface is a concave arc surface, and the punch is pressed to work. This is solved by the first means characterized by forming a thin portion and forming a convex arc surface at the edge on the product side, and in addition to the first means, the thin surface of the punch end surface and the work A second means using a means characterized in that a space is provided in at least one of the parts to be a part and the surplus of the work is moved to the space during pressing is also solved.

(Operation) In the first means, when the upper and lower punches are pressed in the first step, a thin-walled portion is formed on the work at the end face of the punch, and at the same time, the concave arc portion on the side surface of the punch forms an edge on the product side. A chamfer having a convex arc shape is formed.

Further, in the second means, since the surplus of the work at the time of forming the thin portion moves to the concave groove of the punch end surface or the hole provided in the work itself, the work is formed with a low pressing force.

(Example) Hereinafter, the Example of this invention is described with reference to drawings. First
The drawing shows the mold of the first step, in which 1 is a work of a metal plate to be cut, 2 is an upper punch, 3 is a lower punch, 4,
Reference numeral 5 denotes upper and lower pads that support the work 1.

The upper punch 2 has a convex end face 7 and a flat side face 8, and a concave arc surface 9 is formed at the base of the side face 8. On the other hand, in the lower punch 3, a concave groove 11 as a space portion is provided in the end surface 10, and the base portion of the side surface 12 has a concave arc surface 13 similar to the upper punch.
Are formed.

Due to the above-mentioned configuration, when the upper punch 2 is pressed, the work 1 is, as shown in FIG.
A thin portion 15 is formed by being compressed at 10, and the extruded meat is pushed into the concave groove 11 on the lower surface to form the collecting portion 16.
Then, near the end point of the stroke, the concave arc surfaces 9 and 13 press the edges to form chamfered portions 17 and 18 having a radius R.
The intermediate product shown in the figure is obtained.

In the next second step, the mold shown in FIG. 4 is used, and the thin portion 15
To remove. In FIG. 4, 20 is a die, 21 is an internal punch, and 22 is a pad. The work 1 is fixed on the die 20 to punch 22.
When the thin portion 15 is sheared by pressing down, two product 1a are obtained. Thickness of thin portion 15, that is, thickness t of fracture surface 23 in FIG.
Is considerably smaller than the size of the chamfered portions 17 and 18, and smoothing of this portion is easy.

In the above-mentioned embodiment, the thickness of the work is the concave groove 11 of the lower punch 3.
The concave groove may be provided in the upper punch 2 or may be provided in both upper and lower sides, though it flows into the inside to reduce the forming pressure to facilitate the forming.

Next, another method will be described with reference to FIG. In FIG. 6 (a), 30 is a work, and the work 30 is an arc-shaped cutting line 3
Two products with arcuate end faces are made by cutting at 1, 31. Holes 32, 32 as a space portion are punched in the removed portion surrounded by the cutting lines 31, 31.

The punches 33 and 34 for processing the work 30 are vertically symmetrical and have top surfaces 35 and 36 and concave arc-shaped side surfaces 37 and 38 as shown in FIG. 7, and the contours of the top surfaces 35 and 36 are cut. Match lines 31, 31. When the work 30 is placed on the lower punch 34 and the upper punch 33 is pressed down, a thin portion 39 is formed as shown in FIG. 7, and at the same time, the excess thickness moves so as to reduce the holes 32, 32 and the small hole 32a, 3
Transform into 2a. This movement of the meat reduces the molding pressure.

In the next second step, when the thin-walled portion 39 is sheared by a punch having the same contour as the thin-walled portion 39, it has an arc surface.
Individual products 30a, 30a are obtained.

In this embodiment, the forming pressure is reduced by forming a hole in the work, but the forming pressure can be further reduced by using a punch provided with a concave groove as in the above embodiment.

Each of the above embodiments is a method of cutting out two products,
The punching work can be performed by making the punch circular. Further, the present invention can be applied to the work of cutting off the outer edge of the work. In this case, since the surplus meat escapes to the outside in the first step, it is not necessary to provide a space portion into which the surplus meat flows.

(Effects of the Invention) As described above, when cutting the work, the convex chamfered chamfered portions can be formed at the edges of both surfaces of the work at the same time when the thin portion is formed, and the thin portion can be easily cut off.
It has an effect that the cutting and chamfering steps can be performed quickly and efficiently.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a mold used in the first step of one embodiment of the present invention, FIG. 2 is a cross-sectional view during operation, FIG. 3 is a perspective view of an intermediate product, and FIG. 4 is a second step. Sectional view of mold during operation, No. 5
FIG. 6 is a side view of the product, FIGS. 6 (a), (b), and (c) are process explanatory views of another embodiment, and FIG. 7 is a sectional view of the mold in the first process of the embodiment when the mold is in operation. is there. 1,30 …… Workpiece, 1a, 30a …… Product 2,3,33,34 …… Punch, 7,10,35,36 …… End surface 9,13,37,38 …… Concave arc surface, 11 …… Groove (space) 32 …… Hole (space)

Claims (2)

[Claims] 1. A cutting method comprising a first step of pressing a cutting position of a work with upper and lower punches to form a thin portion, and a second step of cutting the thin portion at a boundary between the thin portion and a product side. The punch used in the first step has a protruding end surface and a side surface continuing from the end surface, and at least the base portion of the side surface is a concave arc surface, and a thin wall portion is formed on the work by pressurizing the punch, and is formed on the edge of the product side. A cutting method characterized by forming a convex arc surface. 2. A space portion is provided on at least one of the end surface of the punch and the thin-walled portion of the work, and the excess thickness of the work is moved to the space portion during pressing. Cutting method.