JPH0366434A - Forming method for can cap having strengthened edge - Google Patents

Abstract

PURPOSE:To prevent the protective layer of can body from being damaged with burrs, to eliminate the backward forming process due to the reaction force and to improve the accuracy of product by executing cutting and forming to the metal bland only from the side to be inner surface and controlling the movement of forming device to be only in one direction. CONSTITUTION:In the case of counter-sink forming, at the time when the chuck- wall 11 and the center panel chuck radius 12 are formed, the punch center 6 and the die center 7 which hold and abut on the center part of the metal blank 10 are stopped and the flange part of the metal blank is formed. And the upper pressure sleeve 4 and the die center ring 5 abutted on each other are moved further in the same direction and so the counter-sink is formed. Therefore, because the reaction force is not used at all and the prescribed force is exactly loaded, so the forming variance of counter-sink radius is not generated. Further by operating respective working device from the inner surface of can having no protective layer, so the burries project into the side having no protective layer.

Description

[Detailed description of the invention] [Industrial application field] In the present invention, the edges are strongly 1.1. The present invention relates to a method for forming can lids.

[Prior art] As a method for forming can lids, for example, Japanese Patent Application Laid-Open No. 1983-1938
As described in Publication No. 34 and US Pat. No. 4,571,978, etc., cut edges arranged on concentric circles, a pair of shearing punch and drawing die provided on the center side, and further on the center side. A pair of pull-out punches and a lift ring are arranged in the center of the pull-out punch and lift ring.
A cup-shaped body is formed from a metal blank using a forming device consisting of a pair of butts and a ring, and then a seven-run section is formed, and then a countersink section is formed by moving the lift ring in the opposite direction. Methods for manufacturing can lids are already known.

However, this conventional method has the disadvantage that the formation of the countersink is non-uniform.

As a result of various studies on the cause, the present inventors have found that the cause lies in moving the ring in the opposite direction to perform molding.

Normally, in such press working, in order to utilize the force applied in one direction, it has been common sense to utilize the reaction force of this force. Therefore, a spring or an air cylinder is used in one of the processing devices to exert a force to return the material when the n load is removed, thereby performing one step of molding.

Although this conventional method is certainly superior in terms of saving energy, such reaction force is not necessarily constant and always varies, which can have a negative effect on the molded product. When this molding method was applied to molding can lids, it was found that this was the cause of variations in the accuracy of can lids.

Additionally, conventional molding methods have several other drawbacks.

First, it is necessary to cut the periphery of the metal blank using the cutting edge and move the shearing punch to the position where the cup-shaped body is formed. Since it comes into contact with the surface of the metal blank over a long distance, so-called metal chips are generated, which are brought in by the movement of the shearing punch and the movement toward the center of the metal blank, and may damage the protective layer of the metal blank. , the phenomenon of penetrating occurs frequently.

! ! The layer of the body acts to block the rear corner of the metal from the contents of the can when covered with the can, and protects the metal from corrosion, but if this layer is damaged, it will cause damage to the metal.
Liability may be lost, holes may develop due to corrosion after the contents are filled, and depending on the contents, expansion cans may occur due to the generation of hydrogen gas, and the contents may turn black.
Damage to the A protection layer must be prevented at all costs.

Next, moving the shearing punch to the position where the cup-shaped body is formed requires a long stroke in the manufacturing process due to the long movement distance, which requires a long time to form the lid. However, the number of units produced per unit time is reduced, and since a long smee loaf is required, a large amount of operating energy is required.

The third problem is that the two steps of forming the cup-shaped body, forming the flange section, and then forming the chuck wall section are carried out sequentially, but performing these steps over time is difficult in manufacturing. This causes problems that complicate the process and require a long time.

These are major manufacturing drawbacks.

[Problems to be Solved by the Invention] As a result of various studies, the present inventor has found that there is a limit to improving the accuracy of can lids since forming is performed using reaction force, and that there is a limit to improving the accuracy of can lids. The present invention was completed by elucidating that it is necessary to perform molding by moving each molding device in one direction and not to perform reaction force, so-called return molding.

In addition, by moving the punch cutter, upper pressure sleeve, and punch center in parallel in the same direction, and moving the punch center in advance of the upper pressure sleeve, the flange, chuck wall, and center panel chuck radius can be moved in parallel. The third problem was solved by molding.

[Manual Punching to Solve the Problems] The present invention is based on a method for strongly forming the ends of 11 can lids using a die cutter 1 placed concentrically and an unpaired punch placed closer to the center. A cutter 2 and a die draw ring 3, a pair of upper pressure sleeve 4 and a die center ring 5 arranged closer to the center, and a pair of punch center 6 arranged closer to the center.
and a die center 7, the punch cutter 2, the upper pressure sleeve 4, and the punch center 6 are used to form a metal blank 10 which is not provided with a protective layer and has a protective layer provided at least on the opening that will become the inside of the can. The peripheral part of the metal blank 10 is cut into a circular shape by the punch cutter 2, and the punch cutter 2 is further moved from the cutting position to shape the cup-shaped body 16 and cut the upper pressure sleeve 4. and die center ring 5, fLt<blank 1
The punch center 6 is sandwiched and brought into contact with the die center 7 to form the flange portion of the can lid, and the center side of the metal blank 10 is brought into contact with the punch center 6 to form the die center ring of the metal blank 10. 5 and the radius of the punch center 7, the chuck wall 11
and form the center panel chuck radius 12, and then move the upper pressure sleeve 4 and die center ring 5 to form the counter sink radius 1.
3. A method for forming a can lid in which the end portions are strengthened while all forming sections of a forming device are moved in the same direction.

2. In a method for strengthening and molding the end of a can lid, a die cutter 1 placed concentrically, and a die cutter 1 placed closer to the center,
A pair of punch cutter 2 and a die drawer ring 3; a pair of upper pressure sleeve 4 and a die center ring 5 located closer to the center; and a pair of punch center 6 located closer to the center.
Using a forming device consisting of a die center 7 and a punch cutter 2, an upper pressure sleeve 4, and a punch center 6, forming a protective layer on a metal blank 10 having a protective layer provided at least on the side that becomes the inside of the can. The peripheral part of the metal blank 10 is cut into a circle by the punch cutter 2, and the radius base point 8 of the inner circumferential surface between the centers of the cutter is cut into a circle. Move the outer periphery of the 7-run part of the lid to a position where it is almost the same height as the 7-run part, stop the punch cutter 2 at this position, and remove the outer peripheral wall 1 of the flange part of the can lid.
At the same time, the upper pressure sleeve 4 and the die center ring 5 are brought into contact with each other by sandwiching the metal blank 10 to form the flange portion 15 of the can lid, and at the same time, the punch center preceding the upper pressure sleeve 4 is formed. 6 is brought into contact with the die center 7 between the centers of the metal blank 10, and the center side inner circumference radius of the die center ring 5 of the metal blank 10 and the punch center 7
A chuck wall 11 and a center panel chuck radius 12 are formed between the chuck radius 11 and the center panel chuck radius 12, and then the upper pressure sleeve 4 and the die center ring 5 are moved to form a countersink radius 13. A method for forming can lids in which all the forming parts of the forming device are moved in the same direction and the edges are strengthened. ”.

[Function] In the present invention, in forming the countersink,
Unlike the conventional method, the means for moving the ring in the opposite direction is eliminated, and the metal blank 10 is
The punch center 6 and the die center 7, which are in contact with each other by sandwiching the central part of The counter sink radius 13 is formed by moving the counter sink radius 13.

As a result, it is possible to accurately apply a predetermined force without using any reaction force, so the countersink radius 1
No molding variations occur at all.

This is the first feature of the present invention. In addition, the movement distance of the punch cutter was set to the shortest distance necessary to form the outer peripheral wall of the flange, thereby preventing the generation and introduction of chips and eliminating the drawback of damaging the protective layer.

The stroke is shorter, the production speed is faster, and less energy is required.

Furthermore, by simultaneously moving the punch cutter 2, upper pressure sleeve 4, and punch center 6 in the same direction, and by placing the punch center 6 in the lead, the franchiser, chuck wall 11, and center panel chuck radius 12 are all moved in parallel. This significantly shortened the manufacturing process.

Furthermore, a major feature of the present invention is that these molding devices can be
At least, the effect is applied from the side without the protective layer of the metal blank, which is provided with a protective layer on the side that will become the inner surface of the can.

By doing this, the "burrs", so-called "burrs" that occur at the several curved ends of the metal blank protrude into the acid 1, which has no protective layer.

For this reason, after forming a single lid, in the curling process, which is convenient for stacking and transporting cans and is a preforming step for seaming, the edges with a protective layer are curled directly inward. In a single lid formed by the molding method, the edges always come into contact with the curling device, so they are removed, crushed, or rolled in this process, and do not exist in the form of protruding edges.

Therefore, the opening end of the can during capping and the Mil1 layer of the can body are not damaged by paris when the can is tightened, and corrosion does not occur after the closure, which is one of the features of the present invention.

〔Example] Next, embodiments of the present invention will be described with reference to the drawings.

In the examples, an aluminum A3182P material with a thickness of 0.20 to 0.28 was used as the metal blank, and a protective layer of epoxyphenol resin was provided on the surface that would become the inner surface of the can. A similar effect can be obtained by forming a protective layer using. A resin paint was also applied to the outer surface of fl'2 for purposes such as lubrication.

FIG. 1 is a longitudinal sectional front view of a portion of the molding apparatus used in the present invention. 1 is a die cutter, 2 is a punch cutter, 3 is a die drawer, 4 is an upper pressure sleeve, 5 is a die center ring, 6 is a punch center, and 7 is a die center. These devices are arranged concentrically, with the die cutter 1 on the outer periphery and the die center 7 on the center side. Each of these devices moves in the direction of the arrow to form the metal blank IO. The metal blank 10 is provided with a protective layer at least on the surface that will become the inner surface of the can. Each device contacts the metal blank from the side on which the protective layer is provided and performs the forming process.
Each stage of A, B, C, and D in the figure shows the progress of the molding process.

In stage A, the punch cutter 2 and die cutter 1 cut the metal blank, and the punch cutter 2 and die rolling 3 sandwich the metal blank and move in the direction of the arrow.

In stage B, the punch cutter 2 is moved, the edge of the metal blank 10 forms a vertical wall, the punch center 6 has not yet hit the metal blank, and a cup-shaped nourishing precursor is formed.

In stage C, the upper pressure sleeve 4 sandwiches the metal blank and contacts the die center ring 5 to form a 7 lange 15 and the outer periphery of the flange 14, and the punch center 6 sandwiches the metal blank 10 and contacts the die center ring 5.
It can be seen that the chuck wall 11 and the center panel chuck radius 12 are formed in contact with each other.

At D Fl +1, upper pressure sleeve 4
The die center ring 5 is further moved to form a countersink radius 13.

This embodiment is an embodiment in which each molding device moves in the same direction, molds from the opening of the metal flange provided with the protective layer, and molds sequentially in stages to form a cram school.

FIG. 2 shows another embodiment, using the same apparatus as in FIG. It is shown that the outer periphery of the M body is formed by moving the metal blank in the direction of the arrow. It is understood that the upper pressure sleeve 4 and the punch center 6 are moving in parallel in the direction of the arrow.

It can be seen that at stage B, the punch center 6 moves ahead of the upper pressure sleeve 4, and the metal blank moves toward the center.

At step C, the punch cutter 2 is moved to a position where the radius reference point 8 on the inner circumferential surface on the center side is approximately the same height as the outer circumferential wall of the flange portion of the can lid to be formed, and the punch cutter 2 is stopped at this position. Then, the outer circumferential wall 14 of the flange portion of the can lid is formed, and the punch center 6 and the die center 7, which precede the upper pressure sleeve 4, sandwich and abut the center side of the metal blank 10, and the die center ring 5 is formed. It is shown that a chuck wall 11 and a center panel chuck radius 12 are formed between the center side inner peripheral surface radius and the radius of the punch center 6.

In stage B, the upper pressure sleeve 4 and die center ring 5 are further moved to form a countersink radius 13.

This embodiment has VF characteristics such as a short moving distance of the punch cutter and no generation of chips.

In addition, flange peripheral wall, flange, chuck wall,
The center panel chuck radius is molded at the same time, and as in the example shown in Fig. 1, it is shaped like a cup! ! It is understood that the present invention does not form body precursors or form parts sequentially in a stepwise manner.

It can be seen that in this way, the molding process is shortened and the manufacturing speed is high.

In the present invention, all processes are performed by moving each molding device in the same direction, and the return molding process using reaction force is completely eliminated.

This eliminates variations in the force used for molding and significantly improves the precision of molded products.

FIG. 3 is a sectional view showing curl forming, which is a preforming process for winding the lid onto the can body. Reference numeral 16 denotes a curl forming device, and it is understood that there is a burr, so-called pari 17, which projects outward at the end of the outer circumferential wall of the flange of the lid, and is in contact with the curl forming device.

FIG. 4 shows the burr 17 removed by the curling device.

Furthermore, when the forming device is brought into contact with the opening of the metal blank where the protective layer is provided and the metal blank is cut, the paris disappears during the curling process.

FIG. 5 shows conventional curl forming.

If the metal blank is not contacted by the forming device from a specific direction as in the present invention, the burr 17 will protrude inward during curling and will not come into contact with the curling device, resulting in curling as shown in FIG. It can be seen that the burr 17 that protrudes inward remains even after the molding is completed.

FIG. 7 shows a cross section of the lid wrapped around frIllFI.

It is clearly shown that the burr 17 contacts the can body and damages the protective layer. In addition, if the leakage is severe, the hook part of the can body may be cut and leakage may occur.

[Effects] In the molding of 61 bodies, the present invention cuts and molds the metal blank from the side that becomes the inner surface of the can, prevents damage to the protective layer of the can body due to paris, and also reduces the movement of the molding equipment. direction only, eliminating the molding process in the return direction due to reaction force,
This significantly improves the accuracy of the product.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of the present invention, and is a front sectional view of a part of a molding apparatus used in the present invention, showing each molding apparatus and each stage of the molding process. FIG. 2 shows another embodiment of the present invention, in which each molding device and
The molding process at each stage is shown. FIG. 3 is a front sectional view showing a curling process as a preliminary process for seaming to the can body, and FIG. 4 is a front sectional view at the end of the force-ring process. 5 and 6 are front sectional views showing a conventional curling process, and FIG. 7 is a front sectional view showing a can body in a tightly wound state. l: Die cutter, 2: Punch cutter, 3: Die drawer, 4 Near collar pressure sleeve, 5: Die center ring, 6: Punch center, 7: Die center 10: Metal blank, 11: Chuck wall,
13: Countersink radius, 14: Flange outer peripheral wall, 15: Flange, 16: Curling device, 17: Paris. Figure 3 Figure 4 Taste ( ( Lolo

Claims (1)

[Claims] 1. A method for reinforcing the edge of a can lid, comprising a die cutter 1 arranged concentrically, and a die cutter 1 arranged closer to the center.
A pair of punch cutter 2 and a die drawer ring 3; a pair of upper pressure sleeve 4 and a die center ring 5 located closer to the center; and a pair of punch center 6 located closer to the center.
and a die center 7, the punch cutter 2, the upper pressure sleeve 4, and the punch center 6 are used to form a metal blank 10, which is provided with a protective layer at least on the side that will become the inside of the can, and which is not provided with a protective layer. The peripheral part of the metal blank 10 is cut into a circular shape by the punch cutter 2, and the punch cutter 2 is further moved from the cutting position to form a cup-shaped body 16, and an upper pressure sleeve 4, The die center ring 5 is brought into contact with the metal blank 10 between them to form the flange portion 15 of the can lid, and the punch center 6 is brought into contact with the die center 7 while the center side of the metal blank 10 is held in between. , a chuck wall 11 is formed between the center-side inner circumferential radius of the die center ring 5 of the metal blank 10 and the radius of the punch center 7.
and form the center panel chuck radius 12, and then move the upper pressure sleeve 4 and die center ring 5 to form the counter sink radius 1.
3. A method for forming a can lid in which the end portions are strengthened while all forming sections of a forming device are moved in the same direction. 2. In a method for strengthening and molding the end of a can lid, a die cutter 1 placed concentrically, and a die cutter 1 placed closer to the center,
A pair of punch cutter 2 and a die drawer ring 3, a pair of upper pressure sleeve 4 and a die center ring 5 arranged closer to the center, and a pair of punch centers arranged closer to the center. 6
and a die center 7, the punch cutter 2, the upper pressure sleeve 4, and the punch center 6 are used to form a metal blank 10, which is provided with a protective layer at least on the side that will become the inside of the can, and which is not provided with a protective layer. The peripheral part of the metal blank 10 is cut into a circular shape by the punch cutter 2, and the radius base point 8 of the inner peripheral surface on the center side of the cutter is set at the flange part of the can lid to be formed. The punch cutter 2 is moved to a position that is almost the same as the height of the outer circumference of the can lid.
At the same time, the upper pressure sleeve 4 and the die center ring 5 are brought into contact with each other by sandwiching the metal blank 10 to form the flange portion 15 of the can lid. 6 and metal blank 1 to die center 7.
0, and form a chuck wall 11 and a center panel chuck radius 12 between the center-side inner peripheral radius of the die center ring 5 of the metal blank 10 and the radius of the punch center 7, Next, the upper pressure free 4 and the die center ring 5 are moved to form a countersink radius 13, and the ends are strengthened while all the forming sections of the forming device are moved in the same direction. How to form can lids.