JPH0790305B2 - Molding method for can lid with reinforced edges - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for forming a can lid having a reinforced end portion.

[Prior Art] As a method of forming a can lid, as described in, for example, JP-A-60-193834 and U.S. Pat. No. 4571978, concentrically arranged cut edges and the center thereof are provided. A pair of shear punches and a drawing die provided on the side, a pair of drawing punches and a lift ring arranged on the center side of the pair, and a forming device composed of a pair of pads and rings provided on the center side. A method for producing a can lid by forming a cup-shaped body from a metal blank using the above, then forming a flange portion, and then forming a countersink portion is already known.

However, this conventional molding method has three serious drawbacks.

The first is that the cutting edge has to cut the periphery of the metal blank to move the shear punch to a position where the cup-shaped body is formed, so that the biting distance of the shear punch with respect to the opposing die becomes long, and therefore,
Since the shear punch touches the cross section of the cut metal blank at a long distance, so-called metal swarf is generated, which is brought in by the movement of the shear punch and the movement of the metal blank toward the center to protect the metal blank. The phenomenon of scratching or piercing the layers is frequent.

The protective layer of the lid serves to block contact between the contents of the can and the metal when the can is covered, and protects the metal from corrosion, but if this is damaged, the protective function is lost. After filling the contents, there is a problem that holes may be formed due to corrosion, and depending on the contents, the generation of hydrogen gas may cause expansion cans and blackening of the contents, so damage to the protective layer must be prevented. That is something that must be done.

Next, moving the shearing punch to the position where the cup-shaped body is formed requires a long time to form the lid because the movement distance is large, so the stroke in the manufacturing process becomes long. Since the number of products manufactured per unit time is small and a long stroke is required, large operating energy is required.

A third problem is that a cup-shaped body is formed, a flange portion is formed from this, and then a chuck wall portion is formed. The two steps are sequentially performed. This causes a complicated process and a problem that requires a long time.

These are major manufacturing drawbacks.

[Problems to be Solved by the Invention] As a result of research to solve the above-mentioned drawbacks of the prior art, the present invention cannot solve the above-mentioned drawbacks as long as a cup-shaped body is formed, and a circle cut into a metal blank. The outer circumference is
It forms the outer peripheral wall of the flange of the lid to be molded, and it suffices to form this outer peripheral wall, and there is no need to form this outer peripheral wall after the step of forming a cup-shaped body. By clarifying that, by moving the punch cutter to form the outer peripheral wall of the flange, and stopping at this position and preventing further movement, the generation of cutting chips, damage to the protective layer and long stroke I solved all the problems.

Next, by simultaneously moving the punch cutter, upper pressure, and punch center in the same direction, and moving the punch center ahead of the upper pressure, the flange, chuck wall, and center panel chuck radius are formed in parallel. By the third
It is a solution to the problem.

MEANS FOR SOLVING THE PROBLEM The present invention relates to “1. In a method of reinforced molding of an end portion of a can lid, a die cutter 1 arranged concentrically and a die cutter 1 arranged on the center side thereof.
A pair of punch cutters 2 and a die drawing ring 3, a pair of upper pressure sleeves 4 and a die center ring 5 arranged on the center side thereof, and a pair of punch centers 6 arranged on the center side of the pair.
And a die center 7 are used to form the punch cutter 2, the upper pressure sleeve 4, and the punch center 6 on the side of the metal blank 10 having a protective layer on the inner side of the can where the protective layer is not provided. Move the metal blank 10 to the punch cutter 2
And cut the punch cutter 2 into a circle, and move the punch cutter 2 to a position where the radius base point 8 on the inner peripheral surface of the center side of the cutter is almost the same as the height of the outer peripheral wall of the flange portion of the can lid to be molded. Stop the punch cutter 2 at the position, and the outer peripheral wall of the flange of the can lid.
The wall portion to be 14 is formed, and the upper pressure sleeve 4 and the die center ring 5 are contacted by sandwiching the metal blank 10 to form the flange portion 15 of the can lid. The punch center 6 that precedes the die center 7 is a metal blank.
The center side of 10 is sandwiched and abutted to form a chuck wall 11 and a center panel chuck radius 12 between the center side inner radius of the die center ring 5 of the metal blank 10 and the radius of the punch center 6. Then, the die center 7 is moved in the opposite direction, and the chuck wall 11 and the center panel chuck radius are placed in the gap formed between the die center 7 and the die center ring 5.
A method for forming a can lid with a reinforced end portion, which comprises pressing 12 to form a counter sink radius 13. "
Is.

[Operation] By the above-mentioned special forming process, the moving distance of the punch cutter is the shortest distance necessary for forming the outer peripheral wall of the flange, and the defects that the cutting layer is not generated and brought in and the protective layer is damaged are eliminated.

Also, the stroke is short, the manufacturing speed is high, and the required energy is low.

Further, by simultaneously moving the punch cutter 2, the upper pressure sleeve 4, and the punch center 6 in the same direction, and by moving the punch center 6 ahead, the flange 15, the chuck wall 11, and the center panel chuck radius 12 are all moved in parallel. It was formed and the manufacturing process was significantly shortened.

Furthermore, a great feature of the present invention is that these molding devices are
This is to act from the side of the metal blank on which the protective layer is provided on the side that becomes the inner surface of the can without the protective layer.

By carrying out in this way, the "burr part", that is, a burr, which is formed at the cut end of the metal blank, is projected to the side without the protective layer.

For this reason, after molding the lid, it is convenient for stacking and transporting, and in the curling process, which is a preliminary molding for winding and tightening on the can body, the end is curled with the side with the protective layer inside. In the lid body molded by the molding method of the present invention, burrs always come into contact with the curling device, so that the lid body is not removed, crushed or rolled in this step, and does not exist in a so-called burr-like shape.

Therefore, the opening end portion of the can and the protective layer of the can body are not damaged by the burr when the lid is closed, and corrosion is not generated after the can is formed. This is also a great feature of the present invention.

[Embodiment] Next, an embodiment of the present invention will be described with reference to the drawings. In each example, aluminum A5182P was used as the metal blank.
Material, thickness 0.20 to 0.28 was used, and an epoxy phenolic resin protective layer was provided on the inner surface of the can. The same effect can be obtained by forming the protective layer using a vinyl organosol. A resin coating was also applied to the outer surface of the can for the purpose of lubrication and the like.

FIG. 1 is an embodiment of the present invention and is a vertical cross-sectional front view of a part of a molding apparatus used in the present invention.

1 is a die cutter, 2 is a punch cutter, 3 is a tie rolling, 4 is an upper lesser 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 peripheral side and the die center 7 on the central side. Each of these devices is moved in the arrow direction to form the metal blank 10. The metal blank 10 is provided with a protective layer on at least the inner surface of the can. Each device contacts the metal blank from the surface side on which the metal blank is provided and performs the forming process. Each stage of A, B, C and D in FIG. 1 shows the progress of the molding process.

In the stage A, the punch cutter 2 and the die cutter 1 cut the metal blank, and the punch cutter 2 and the die drawing ring 3 sandwich the metal blank and move in the arrow direction. It can be seen that the upper pressure sleeve 4 and the punch center 6 move in parallel in the arrow direction.

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

At step C, the radius base point 8 on the inner peripheral surface of the center side of the punch cutter 2 is moved to a position approximately the same as the height of the outer peripheral wall of the flange portion of the can lid to be molded, and the punch cutter 2 is stopped at this position. To form the outer peripheral wall 14 of the flange portion of the can lid, and to punch the punch center 6 and die center 7 ahead of the upper pressure sleeve 4.
The center side of the metal blank 10 is sandwiched between and abutted, and the chuck wall 11 and the center panel chuck radius 12 are formed between the center side inner peripheral radius of the die center ring 5 and the radius of the punch center 6. It is shown.

At the stage D, the die center 7 is moved in the opposite direction, and the chuck wall 11 and the center panel chuck radius 12 are placed in the gap formed between the die center 7 and the die center ring 5.
It is shown that the counter sink radius 13 is formed by pushing in.

FIG. 2 is a sectional view showing curling, which is preforming for winding the lid around the can body.

It is understood that the curl forming device 16 has a burr 17 which is a burr 17 protruding outward at the end of the outer peripheral wall of the flange of the lid and is in contact with the curl forming device.

FIG. 3 shows that the burr 17 has disappeared by the curl device.

Thus, when the molding device is brought into contact with the metal blank from the side where the protective layer is provided and cut, the burr disappears in the curling process.

FIG. 4 shows the conventional curl molding. As in the present invention, if the metal blank is not subjected to the contact processing of the molding device from a specific direction, the burr 17 will protrude inward during the curl molding and will not come into contact with the curl molding device. Therefore, as shown in FIG. It can be seen that the burrs 17 protruding inward are present even after the curl molding is completed.

FIG. 6 shows a cross section in which the lid is wound around the can body. Bali 17
Is clearly in contact with the can body and damages the protective layer. In addition, when the burr is severe, the hook part of the can body may be cut and leaked.

[Effects] According to the present invention, the moving distance of the punch cutter is made extremely short to eliminate the generation of cutting chips, the damage of cutting chips is solved, and the molding devices arranged concentrically are moved in parallel so that the lid is closed. By simultaneously forming the outer peripheral wall of the body, the flange, the chuck wall, and the center panel chuck radius, the molding process was shortened and the manufacturing speed could be increased. Further, by cutting and cutting the metal blank from the side where the protective layer is not provided, the problem of damage to the can body due to burrs was solved.

[Brief description of drawings]

FIG. 1 is a front sectional view of a part of a molding apparatus used in the present invention, showing the molding process at each stage. FIG. 2 is a front cross-sectional view showing a curling step which is a preliminary step of winding around the can body, and FIG. 3 is a front cross-sectional view at the end of the curling step. 4 and 5 are front cross-sectional views showing a conventional curling process, and FIG. 6 is a front cross-sectional view showing a state in which the can body is wound and tightened. 1: Die cutter, 2: Punch cutter, 3: Die drawing ring, 4: Upper pressure sleeve, 5: Die center ring, 6: Punch center, 7: Die center, 10: Metal blank, 11: Chuck oar, 13: Counter Syncradius, 14: Flange outer wall, 15: Flange, 16: Curling device, 17: Burr.

Claims (1)

[Claims] 1. A method of reinforced molding the end of a can lid, comprising:
A die cutter 1 arranged concentrically, a pair of punch cutters 2 and a die drawing ring 3 arranged on the center side thereof, and a pair of upper pressure sleeves 4 and a die center ring arranged further on the center side thereof. 5 and a pair of punch centers 6 arranged on the center side thereof.
And a die center 7 are used to form the punch cutter 2, the upper pressure sleeve 4, and the punch center 6 in the metal blank 10 having a protective layer on the inner side of the can, which is not provided with the protective layer. To the side, and the peripheral portion 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 of the punch cutter 2 on the center side of the cutter is the flange portion of the can lid to be formed. It moves to a position that is almost the same as the height of the outer peripheral wall, stops the punch cutter 2 at this position, and sets the outer peripheral wall 14 of the flange portion of the can lid.
Forming a wall portion to be the metal blank and forming the upper pressure sleeve 4 and the die center ring 5 into a metal blank.
A flange portion 15 of the can lid is formed by sandwiching and abutting 10 and, in parallel, the punch center 6 preceding the upper pressure sleeve 4 and the die center 7 are metal blanks.
The center side of 10 is sandwiched and abutted to form a chuck wall 11 and a center panel chuck radius 12 between the center side inner circumference radius of the die center ring 5 of the metal blank 10 and the radius of the punch center 6. Then, the die center 7 is moved in the opposite direction, and the chuck wall 11 and the center panel chuck radius are placed in the gap formed between the die center 7 and the die center ring 5.
A method for forming a can lid with a reinforced end portion, which comprises pressing 12 to form a counter sink radius 13.