JPH01299787A - Welded can and manufacture thereof - Google Patents

Abstract

PURPOSE:To improve joining strength and combined efficiency of a can by combining top sheet or bottom sheet to the can body as double seaming irradiating laser beam around center of the seaming part and joining as melting over the whole circumference in plural pieces of the metal plates. CONSTITUTION:A body hook 4 is formed to the can body 1 with bending work and cover hook 5 for joining are formed to the top sheet 2 or bottom sheet 3 side. Successively, after forming the seaming part 6 by overlapping the hooks 4, 5, the center part of the can seaming part 6 is laser-welded over the whole circumference with a laser beam irradiating apparatus set at outside. To plural pieces of the metal sheets 1-5, suitable pieces of integrated melting weld can be executed. By this method, as the metal sheets 1-5 can be mutually welded as integrating, the can body 1 and the top sheet 2 or bottom sheet 3 are firmly joined and the joined strength is improved. As the working speed is rapid, the combined efficiency of the can is improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a three-piece can consisting of a can body plate, a top plate, and a base plate, or a metal can consisting of a bottom body plate and a top plate. This invention relates to a method for manufacturing a can body, typically a two-piece can consisting of two parts, which seals leakage at the top and bottom joints of the can body.

[Prior Art] Metal cans are generally represented by three-piece cans and two-piece cans as described above, but in both cases, the top, bottom plate (b) and can body (a)
) are fixedly connected by a so-called double seaming method, in which the edges of the two are brought together and rolled outward, as shown in Figure 3, to prevent the contents from leaking to the outside.
This seaming component is filled with an adhesive or sealant (C) (usually a rubber compound), or the seaming portion (d)
It was soldered (e) around the copper joint on the outside of the tube to seal it.

[Problems to be Solved by the Invention] Recently, when metal containers are used, if the can body is deformed by external force due to vibration, dropping, overturning, etc., the joints, which are considered to be the weak points of the can body, are likely to break. Strict safety performance has come to be required to prevent the contents from leaking.

In order to cope with such a situation, there is a possibility that conventional bonding methods such as compound and brazing (soldering) are not strong enough, so a bonding method with even higher strength is desired.

In addition, as shown in Figure 4, hooks (C) and (D) are provided at the mutual ends of the can body (A) and the base plate (B), and the mutual hooks (C) and (D) are overlapped. A method has been adopted in which electrical resistance welding is carried out by passing electricity between the electrode rollers, and after this welding, both hooks are wound and fixed as shown in Fig. 4 (C). It is suitable for joining the can body and top and bottom plates of large cans with a wide seam width, such as drum cans, but it is suitable for joining the can body and top and bottom plates of 18I2 cans, smaller round cans, horns, etc. If the seam width is small and the seam width is small, it is very difficult to weld the seam part using electric resistance welding. The joint was tightened to prevent leakage from the joint.

In addition, in order to perform the electric resistance welding described above, it is necessary to coat the inner and outer surfaces of the can (
If the can is coated with varnish, lacquer, etc. to prevent rust or corrosion, the coating applied to the can will have an insulating effect, so either remove the coating in the area to be welded in advance, or remove the coating from the beginning. It has to be left unpainted and therefore needs to be repaired after welding, which is very troublesome.

[Means for Solving the Problems] The present invention was invented in order to cope with such a situation, and it is possible to reduce the outer periphery of the seamed portion of a can without wasting any conventional can making equipment. Some attempts have been made to solve the problem simply by attaching a laser beam irradiation device to the surface.

That is, in the present invention, regardless of whether it is a large can, a small can, a round can, or a horn, can body parts are manufactured using conventional can manufacturing equipment and can manufacturing methods.
Can body (1) and top plate (2) or base plate (3) are manufactured using conventional processes.
) is double-sealed to complete the final process, and this can body is attached to the laser beam circulating irradiation device (7), and the can body (1)
(Technically, it is easier to rotate the can body while the laser irradiation lens is fixed), or to rotate the laser irradiation lens around the can body. The plate material that forms the seaming part (6) by irradiating the laser beam almost all the way around the center and irradiating it around the entire circumference (technically called the cover hook (5) and body hook (4)) A plurality of sheets are melted and fixed (9) and integrated to seal the contents from leakage, and the minimum number of melted sheets is that the cover footer (5) and the body hook (4) are welded. is essential, and the number beyond that may be ■■■, or up to all of ■■■■■, and the number of sheets to be fused can be freely selected by adjusting the laser output.

[Function] In this way, the can body (1) and the top plate (2), or the can body (1)
The double-sealed part (6) of the base plate (3) and the main plate (3) are welded by laser beam irradiation, and the metals melt together and are fixed together, making it difficult to use conventional bonding methods (compound bonding). It has been confirmed that its breaking strength is incomparably greater than that of other methods (such as bonding, adhesion, and soldering), and that even if the plate itself breaks, the joint will not be destroyed.

[Example] The present invention will be described in detail with reference to the drawings below. (1) is a round or square can body formed from a metal plate, (2) is a top plate, (3) is a base plate (bottom plate), There is a body hook (4) with the edge of the can body (1) bent slightly outward, and a top and bottom plate (2).
) and (3) are formed with a cover hook (5) for joining, and the can body (1) is overlapped with each other by a seaming machine.
After curling the can body outward to form seaming parts (6) and forming the combined can body, a laser beam irradiation device (7) is installed on the outside of each seam part (6), and a laser beam is applied to the winding part. The laser beam (10) irradiates the tightening part (6) so that the laser beam receiving position does not change while irradiating substantially the center of the tightening width (8). It is laser welded, and as shown in the figure, multiple pieces can be continuously welded together as one unit, resulting in high welding strength and highly reliable joints, and can reliably prevent leakage of contents from the winding joints. .

[Effects of the Invention] As described above, the present invention irradiates the seamed portion of the can body with a laser beam from the outside along the seamed outer periphery to remove the can body and the top plate.
Alternatively, multiple metal plates that make up the seamed part between the can body and the main plate (bottom plate) are melted and fixed around the entire circumference to seal the can joint, and the number of melted plates is It is essential that the can body and top plate or base plate are welded at the minimum, and beyond that, the number of welded metal plates can be freely selected by adjusting the laser output, and the welded seam part Since the metals melt together and become fixed together, the breaking strength is incomparably greater than that of conventional bonding methods (compounding, gluing, and soldering), and the plate material itself It was confirmed that the joint has enough strength that it will not be destroyed even if it breaks. Therefore, metal containers formed by this method have a high degree of safety as they will not break at the joints due to drop impact, etc., and will not leak the contents, and will not waste conventional can manufacturing equipment at all. It is extremely easy to manufacture, has a fast processing speed, and can be manufactured efficiently. In addition, unlike electric resistance welding, it is possible to process the inner and outer surfaces without having to remove the insulation coating or paint film, and even if the width of the outer seaming edge is small, the can body and top and bottom plates are already double-layered. The items that can be physically joined together using the seaming method are melted and bonded with a laser beam to create a perfect sealing bond, and the product looks no different from conventional double-sealed cans, and is both durable and aesthetically pleasing. It has good effects.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the process of sealing and joining the seamed portion between a can body and a top plate or a can body and a bottom plate (bottom plate) according to the method of the present invention, and FIG. This is a schematic view of a seamed metal can, with a part cut away. Figures 3 (A) and (B) are explanatory diagrams showing the conventional machining process of the seamed part, and Figures 4 (A) and (B).
) and (C) are explanatory diagrams showing the manufacturing process of drum cans and the like by conventional electric resistance welding. (1) is the can body, (2) is the top plate, (3) is the base plate, (4) is the body hook, (5) is the cover hook, (6) is the seaming part, (7) is the ray beam irradiation device, (8) is the width of the seaming part, and (10) is the laser beam.

Claims (1)

[Claims] 1. A can body is formed by wrapping and fastening a top plate or a base plate on a can body manufactured by known technical means by double seaming, and the can body is exposed to a laser beam irradiation device. The can body can be rotated at a position where the laser beam is irradiated approximately at the center of the seaming width, or the laser beam can be irradiated around the entire circumference of the seaming part to form multiple seaming parts. A welded can in which two metal plates are melted and bonded around the entire circumference, and the joints of the top, bottom plate, and can body are hermetically joined by metal welding. 2. After double-sealing the end of the can body and the top plate or base plate,
A laser beam is irradiated on the seamed part from the outside along the seamed outer periphery, melting and fixing the multiple metal plates that make up the seaming part all around the circumference and integrating them. The number of plates to be fixed is adjusted by adjusting the welding depth of the multiple metal plates that make up the seaming part by adjusting the intensity of the laser beam irradiated from the outer periphery of the seaming part or the distance between the outer surface of the seaming part and the laser emission base. A method for manufacturing a welded can that seals the top and bottom joints.