JP5668434B2 - Manufacturing method for square cans - Google Patents

Description

  The present invention relates to a method for manufacturing a square drawn can.

  Conventionally, a technique for manufacturing a container such as a rectangular can by drawing is known. Such a rectangular can is composed of a can body and a lid. When manufacturing the can body, first, an intermediate product including a flat plate portion (can bottom portion), a can body portion, and a protruding portion provided along the periphery of the can body portion by drawing a metal plate material. Manufacturing. Then, a can main body is obtained by trimming off a part of overhang | projection part by trimming and forming the winding flange part. And a lid | cover is attached by tightening to the flange part for winding tightening provided along the opening edge part of this can main body.

  As described above, when a container such as a rectangular can is manufactured by drawing, the can body may be distorted (twisted) after trimming. The cause of this phenomenon will be described with reference to FIGS. 5 and 6 are explanatory diagrams for explaining the cause of distortion in the can body. 5 shows a state in which a part of the can body is seen in cross section, and FIG. 6 shows a state in which the can body is seen obliquely from the bottom side of the can body.

  FIG. 5A shows a part of the cross section of the intermediate product 100a obtained by drawing the plate material. The intermediate product 100a includes a flat plate portion (can bottom portion) 110, a can body portion 120, and an overhang portion 140. When drawing is performed, stress remains inside the deformed portion of the metal plate. That is, for example, as shown in an enlarged view of the deformed portion between the flat plate portion 110 and the can body portion 120, the tensile stress Ps remains inside the bent portion, and the compressive stress Pc remains outside. doing. As a result, a moment is generated in the can body 120 in the direction in which the opening end side opens outward (in the direction of arrow M in the figure).

  Here, in the state before trimming, since the can body 120 is supported by the overhanging portion 140 provided along the periphery of the can body 120, the shape of the intermediate product 100a is maintained. However, when trimming is performed to cut off a part of the overhanging portion 140 to form the winding flange portion 130 (see FIG. 5B), the size of the overhanging portion 140 overhanging the periphery of the body portion 120 is reduced. Shorter. Therefore, the force that supports the can body 120 by the overhanging portion 140 is weakened, and the can body 100 may be distorted. That is, as described above, a moment acts on the can body 120 in the direction in which the winding flange portion 130 opens outward. Therefore, if the force that supports the can body 120 by the winding flange portion 130 is weak, for example, in the case of the rectangular can shown in FIG. 6, the balance may not be achieved and the twist may occur around the diagonal line in the figure. In this way, if twisting occurs, it may cause a winding failure when the lid is attached.

  Such distortion (twist) is likely to occur when a can body is manufactured by shallow drawing. That is, it is likely to occur when a can body of a container having a shallower body depth than the bottom portion is manufactured by drawing. Further, the harder the metal plate material, the larger the springback amount, and this is particularly likely to occur when aluminum alloy, titanium alloy, high-tensile steel, or the like is employed. Furthermore, it tends to occur when the metal plate is thin and the strength due to the can shape is low.

Conventionally, as a countermeasure against such distortion deformation, the deformation of the body due to residual stress has been suppressed by increasing the strength by increasing the thickness of the metal plate material. However, when the thickness of the metal plate is increased, not only the amount of necessary material increases, but also the weight of the can (container) becomes heavy, which may cause a decrease in the conveyance efficiency. Therefore, it is desired that a thinner metal plate material can be employed.

JP 2008-105088 A Japanese Patent Laid-Open No. 04-091825 JP 07-31068 A JP 2000-285872 A

  An object of the present invention is to provide a method for manufacturing a rectangular can, which can suppress deformation of the rectangular can.

  The present invention employs the following means in order to solve the above problems.

That is, the manufacturing method of the square drawn can of the present invention,
A substantially rectangular flat plate portion, a substantially rectangular tube-shaped can body portion rising from the periphery of the flat plate portion, and a winding flange portion provided along the periphery of the can body portion opposite to the flat plate portion; A square-shaped can with
A squeeze that forms an intermediate product comprising the flat plate portion, the can body portion, and an overhang portion provided along a peripheral edge of the can body portion on the opposite side of the flat plate portion by squeezing a metal plate material. Process,
After the drawing step, a trimming step for forming the winding flange portion by trimming the overhang portion;
In the manufacturing method of the square-shaped aperture can formed by:
Between the drawing step and the trimming step, the intermediate product is heated to have a heating step for attenuating the residual stress of the deformed portion of the metal plate material.

  According to the present invention, the residual stress of the deformed portion of the metal plate material is attenuated (or removed in some cases) by the heating process after the drawing. Therefore, when forming the winding flange portion, by trimming off a part of the overhanging portion by trimming, the size of the overhanging portion protruding along the peripheral edge of the can body portion is shortened, and the can body portion is supported. Even if the force becomes weak, the deformation of the can body can be suppressed.

  As described above, according to the present invention, it is possible to suppress the deformation of the rectangular aperture can.

It is the perspective view which looked at the square-shaped aperture can which concerns on the Example of this invention from the bottom part side. It is the perspective view which looked at the intermediate product which concerns on the Example of this invention from the bottom part side. It is a figure which shows a mode when the trimming process is performed to the intermediate product which concerns on the Example of this invention. It is a manufacturing-process figure of the square shaped can according to the Example of this invention. FIG. 5 is an explanatory diagram for explaining the cause of distortion in the can body. FIG. 6 is an explanatory diagram for explaining the cause of distortion in the can body.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be exemplarily described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. .

(Example)
With reference to FIGS. 1-4, the manufacturing method of the square shaped can according to the Example of this invention is demonstrated. In addition, in a present Example, it demonstrates taking the case of the can main body (can before attaching a lid | cover by winding tightening) of a square drawn can.

<Square cans>
A can body 10 of a rectangular can obtained by the manufacturing method according to the present embodiment will be described with reference to FIG. The can body 10 has a flat plate portion 11 as a substantially rectangular can bottom, a cylindrical can body portion 12 rising from the peripheral edge of the flat plate portion 11, and a peripheral edge of the can body portion 12 opposite to the flat plate portion 11. And a winding flange portion 13 provided along. This can main body 10 is a drawn can whose depth of the can body is shallower than the size of the bottom of the can obtained by shallow drawing. That is, the depth of the body portion is shallower than the size of the bottom of the can, and more specifically, the length of the short side of the substantially rectangular flat plate portion 11 is L, and the can body portion When the depth of 12 is W, the can satisfies L> W. An example of the material for the can body 10 is preferably an aluminum alloy, but other examples include tin plate, plated steel plate such as TFS, titanium alloy, and high-tensile steel.

  After putting the contents into the can main body 10 configured as described above, a rectangular drawn can is obtained by attaching a lid (not shown) so as to close the opening of the can main body 10. This lid (not shown) can be attached by tightening the winding flange portion 13 provided along the opening end of the can body 10. In addition, since it is a well-known technique regarding the attachment of the lid | cover by winding, the description is abbreviate | omitted.

<Manufacturing method of square drawn can>
In particular, with reference to FIG. 2 to FIG. 4, a method for manufacturing the can body 10 which is a rectangular drawn can according to this embodiment will be described.

  FIG. 2 is a perspective view of the intermediate product 10a obtained by drawing, as viewed from the flat plate portion 11 side. As shown in the drawing, an intermediate product 10a including a flat plate portion 11, a can barrel portion 12, and a protruding portion 14 provided along the periphery of the can barrel portion 12 on the opposite side to the flat plate portion 11 is obtained by drawing. can get.

  FIG. 3 is a perspective view seen from the flat plate portion 11 side showing a state where the can body 10 is obtained by trimming the intermediate product 10a. As shown in the drawing, a part of the overhanging portion 14 is cut off by trimming, whereby the winding fastening flange portion 13 is formed and the can body 10 is obtained. In the figure, reference numeral 15 denotes a cut-off portion.

  Next, with reference to FIG. 4 in particular, the manufacturing process of the can body 10 according to the present embodiment will be described.

<< Drawing process >>
The intermediate product 10a described above is manufactured by drawing the metal plate. FIG. 4A shows the intermediate product 10a. The left side of the figure is a bottom view of the intermediate product 10a as viewed from the bottom side, and the right side of the figure is an XX cross-sectional view of the left side figure. Since the technique for producing the intermediate product 10a as shown in the drawing by drawing the metal plate material is a known technique, a detailed description thereof will be omitted.

  In the intermediate product 10a obtained by drawing as described above, stress remains in the deformed portion of the metal plate material. That is, as described in the background art, a moment is generated in the can body 12 in a direction in which the opening end side (the projecting portion 14 side) opens outward. However, the overhanging portion 14 provided along the peripheral edge (opening end portion) of the can body portion 12 has a wide width and a high strength. Accordingly, since the can body 12 is supported by the overhanging portion 14, the intermediate product 10a is not deformed by the residual stress.

<< Heating process >>
The intermediate product 10a obtained as described above is heated by the oven 20 (see FIG. 4B). Thereby, the stress (residual stress) remaining inside the deformed portion of the metal plate material can be attenuated. Here, it is desirable to completely remove the residual stress, but it is difficult in practice, and some residual stress may remain. In other words, this heating step is performed to suppress or prevent the can body portion 12 from being deformed and distorted (twisted) by the residual stress after the trimming step described later. The winding flange portion 13 obtained by trimming also has a strength for suppressing or preventing the deformation of the can body portion 12, so that the deformation of the can body portion 12 can be suppressed by the winding flange portion 13. If so, residual stress may remain after the heating step. Note that the heating temperature and heating time at which the residual stress can be sufficiently removed vary depending on the material and thickness of the metal plate material. For example, when an aluminum material (5052 series) having a thickness of about 0.5 mm is used as the metal plate material, the outer dimension of the intermediate product 10a (including the protruding portion before trimming) is about 350 mm long side and short side About 200 mm, height 40 mm, opening size is 300 mm long side and 140 mm short side, and residual stress can be almost removed by heating the intermediate product 10 a at 200 ° C. for 60 to 150 seconds. .

<< Trimming process >>
A part of the overhanging portion 14 in the intermediate product 10a in which the residual stress is attenuated is cut off by trimming to form the winding flange portion 13. Thereby, the can main body 10 can be obtained. FIG. 4C shows the can body 10. The left side of the figure is a bottom view of the can body 10 viewed from the bottom side, and the right side of the figure is a YY sectional view of the left side figure. Since trimming is a known technique, detailed description thereof is omitted.

<The excellent point of the manufacturing method of the drawn product which concerns on a present Example>
According to the manufacturing method according to the present embodiment, the residual stress of the deformed portion of the metal plate material is attenuated (or removed in some cases) by the heating process after the drawing process. Therefore, by trimming off a part of the overhanging portion 14 to form the winding flange portion 13 by trimming, the dimension of the overhanging portion 14 protruding along the peripheral edge of the can body portion 12 is shortened. Even if the force for supporting the can body portion 12 becomes weak, the deformation of the can body portion 12 can be suppressed. Thereby, the trouble of the winding fastening for attaching a lid | cover can also be eliminated after that.

  As described above, the deformation of the can body portion 12 can be suppressed, so that distortion (twist) can be suppressed even in a processed product obtained by shallow drawing, in which distortion (twist) is relatively likely to occur. it can. Further, even if a hard material with a large spring back is used as the material of the metal plate material to be drawn, deformation after trimming can be suppressed, so that the range of material selection is expanded. Furthermore, even if the metal plate thickness is thin and the strength due to the can shape is low, deformation after trimming can be suppressed, so that the plate thickness of the metal plate material can be reduced. As a result, the amount of the metal plate material can be reduced, and the can body 10 can be reduced in weight. Accordingly, the conveyance efficiency is improved and the cost is reduced.

In addition, in the heating process, when the lubricating oil adheres to the intermediate product 10a, there is an effect of evaporating and reducing or removing the lubricating oil.

DESCRIPTION OF SYMBOLS 10 Can main body 10a Intermediate product 11 Flat plate part 12 Can trunk | drum 13 Flange part for clamping 14 Overhang part 20 Oven Pc Compressive stress Ps Tensile stress

Claims (1)

A substantially rectangular flat plate portion, a substantially rectangular tube-shaped can body portion rising from the periphery of the flat plate portion, and a winding flange portion provided along the periphery of the can body portion opposite to the flat plate portion; A square-shaped can with
A squeeze that forms an intermediate product comprising the flat plate portion, the can body portion, and an overhang portion provided along a peripheral edge of the can body portion on the opposite side of the flat plate portion by squeezing a metal plate material. Process,
After the drawing step, a trimming step for forming the winding flange portion by trimming the overhang portion;
In the manufacturing method of the square-shaped aperture can formed by:
A method of manufacturing a square drawn can, comprising a heating step of heating the intermediate product between the drawing step and the trimming step to attenuate residual stress in the deformed portion of the metal plate material.

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