WO2018193524A1

WO2018193524A1 - Metal container manufacturing process

Info

Publication number: WO2018193524A1
Application number: PCT/JP2017/015608
Authority: WO
Inventors: 具実小林; 勇貴山村
Original assignee: 東洋製罐グループホールディングス株式会社
Priority date: 2017-04-18
Filing date: 2017-04-18
Publication date: 2018-10-25

Abstract

A metal container manufacturing process according to the present invention comprises: a step of preparing a rod 1 made of metal; a step of fabricating a container slug 3 by cutting the rod 1 at a certain height; and a step of subjecting the container slug 3 to plastic forming into a container shape.

Description

Metal container manufacturing method

The present invention relates to a method for manufacturing a metal container.

Conventionally, squeezing and ironing (DI molding) has been widely adopted as a method for producing metal containers represented by aluminum cans (for example, Patent Document 1).
This method uses a metal plate, punches out the metal plate to produce a circular slag, squeezes the slag, redraws it, and then forms it by ironing to reduce the thickness. It is a technique to do.

Such DI molding has the advantage that the can body side wall and the bottom can be thinned, a can excellent in lightness can be obtained, and a can with a high height and gloss on the outer surface can be obtained. However, there is a drawback that punching waste is generated and material loss is large.

In addition to the DI molding, a technique called impact molding is also widely used (see, for example, Patent Document 2). This method uses a thin disk-shaped slag obtained by punching a base plate, puts this slag between a die (female) and a punch (male) and presses it to make metal (slag) This is a method of forming a can body at a stretch by extruding, and there is a merit that a can body can be obtained in one process in one mold, but the skin of the can body wall is extremely rough and a glossy outer surface can be obtained. There is a drawback that it is difficult.

Further, when manufacturing cans of various sizes having different diameters and heights by impact molding, two methods are roughly known.
One is a method in which the diameter of the slag is set approximately equal to the diameter of the target can and the thickness of the slag is precisely set to a value calculated from the target can height and diameter. For this reason, this method has the disadvantages that a punching die is required for each slag diameter, and that various base plates having different plate thicknesses must be prepared for forming the slag.
Alternatively, when producing cans of the same diameter, make the slag for the tallest can, then make a blank can and trim it to the required height. In this method, cans of various heights are produced, and there is a drawback that material loss is remarkably increased as cans having a low height are manufactured.
In any case, punching waste is generated in the process of punching slag from the base plate, resulting in a large material loss.

As described above, all the manufacturing methods have advantages and disadvantages, and the improvement is required at present.

Japanese Patent Publication No. 2-30930 JP-A-6-279888

Accordingly, an object of the present invention is to provide a method for producing a metal container that has little material loss, and that can easily change the slag used for plastic working according to the intended diameter and length of the container. It is in.
Another object of the present invention is to provide a method for producing a metallic container capable of producing a glossy metallic container with reduced material loss.

According to the present invention,
Preparing a metal rod;
Cutting the rod at a constant height to produce a container slag;
Plastically processing the container slag into a container shape;
A process for making a metal container is provided.

In the production method of the present invention,
(1) The rod is made of aluminum or aluminum alloy,
(2) Use a rod made of pure aluminum having an aluminum content of 99.0% by mass or more as the rod.
(3) performing the plastic working by at least one molding means selected from the group consisting of impact molding, drawing, redrawing and ironing;
Is preferred.

The metal can manufacturing method of the present invention is characterized by producing a slag to be subjected to plastic working by cutting a metal rod, thereby making it possible to manufacture a metal container with greatly reduced material loss. it can. That is, in the method of punching a metal plate to produce a slag and subjecting this slag to plastic working to form a container, punching waste is generated during the production of the slag, resulting in a large material loss. However, if the slag is produced by cutting the rod, the rod is cut so that the required amount can be obtained according to the size and thickness of the target container, and this is used as a slag for plastic processing, resulting in material loss. The metal container can be manufactured at a material utilization rate close to 100%. Further, when changing to a container having a different size or thickness of the target container, it can be easily handled by changing the position where the rod is cut.

Further, in the present invention, the plastic processing of the slag obtained by cutting the metal rod is performed by at least one forming means among impact forming, drawing forming, redrawing forming, and ironing forming, so that the height is particularly high. Metal cans, such as beverage cans, aerosol cans, battery cases, aluminum tubes, etc., can be easily manufactured, especially by performing ironing to effectively reduce the wall thickness of the body wall and bottom wall, and glossy metal containers Can be obtained.
Such a method for producing a metal container according to the present invention is particularly suitable for producing a container made of aluminum or an aluminum alloy, and is most suitable for producing a so-called aluminum can.

The figure which shows an example of the process of the manufacturing method of the metal container of this invention.

Referring to FIG. 1 showing an example of a process for producing a metal container of the present invention, as shown in FIG. 1 (a), as a starting material, in the present invention, a metal made of a target container material is used. A rod 1 made of steel is used and cut to create a disc-shaped slag 3 having a predetermined length (see FIG. 1B). This slag 3 is, for example, shown in FIGS. 1C to 1E. The target metal container 5 is manufactured by being subjected to plastic working as shown in FIG.

In the present invention, the rod 1 shown in FIG. 1A is manufactured by, for example, hot forging, cold forging, hot rolling, cold rolling, extrusion molding, pultrusion molding, casting, or the like. It has a round bar shape, and may be made of steel, aluminum, aluminum alloy, etc., depending on the intended container material, but the viewpoint of manufacturing a thin and lightweight container It is most preferable to use what is made of aluminum or aluminum alloy to produce a so-called aluminum container.
Also, from the viewpoint of excellent ductility and plastic workability, and the resulting container is excellent in corrosion resistance, a product made of pure aluminum having an aluminum content of 99.0% by mass or more, such as A1070, etc. The rod 1 made of is most preferably used. Furthermore, the rod 1 manufactured by mixing pure aluminum with the aluminum material collected from the used beverage can can also be used, thereby improving the recyclability.
The rod 1 is cut to form a slag 3 for a container. That is, by repeatedly cutting the rod 1 at a predetermined interval in the height direction and the vertical direction, a large number of container slags 3 can be obtained.

In order to manufacture the metal container 5 according to the present invention, first, as shown in FIGS. 1 (a) and 1 (b), a rod 1 having a diameter t is cut at a position of height h, The disk-shaped slag 3 having a bottom diameter t ′ and a height h ′ is produced by pressing. In addition, as a means for cutting the rod 1, it can be performed by a known cutting method. For example, although not shown, a cutting method such as shearing that does not generate chips is preferable because of less material loss. The height h of the slag 3 is set according to the diameter t of the rod 1 from the size (weight, etc.) of the metal container 5 to be finally formed.
When changing the size of the target container, the size of the slag 3 can be changed by changing the diameter of the rod 1, but the rod 1 having the same diameter is used and the cutting height h is changed. Just do it.
As a result, material loss can be greatly reduced, molding can be performed at a material utilization rate close to 100%, and the size of the target metal container 5 can be easily changed.
If the height h ′ of the slag 3 becomes excessively large, the plastic working in the next step may be difficult. Therefore, the diameter t of the rod 1 is also set to the size of the finally obtained metal container 5. Accordingly, it is desirable that the height h ′ is approximately several millimeters.
In order to produce the disc-shaped slag 3, the member with the rod 1 cut may be pressed in the height direction. For example, if the container is a rectangular container (not shown), the pressing direction may be changed. In addition to the power press, a rolling machine, a forging machine, or the like can be used as an apparatus for pressing depending on the shape and dimensions of the slag.

The slag 3 produced as described above is subjected to plastic working. Prior to this plastic working, annealing is performed to remove residual stress, recover coarse grains, and recover work hardened structure. For example, the slag 3 made of pure aluminum is heated to about 345 ° C. to 350 ° C. and then gradually cooled, although it depends on the material of the slag 3. In addition, annealing can also be performed in the middle of the process of producing the slag 3 as needed.

The plastic working of the slag 3 is not particularly limited as long as it is a means that can be shaped into the shape of the container using such a disk shape, and means according to the material of the slag 3 (rod 1) can be adopted. In the present invention, the plastic working is preferably performed by at least one molding means selected from impact molding, drawing, redrawing and ironing, and in particular, these molding means may be used in combination. Is preferred.

For example, as shown in FIGS. 1C to 1E, impact molding is performed, the cup 11 is molded (see FIG. 1C), and then drawing (redrawing) molding is performed to reduce the diameter. The bottomed drawn molded body 13 thus formed is molded (see FIG. 1 (d)), and finally, iron molding is performed, whereby the metal container 5 having a thin can body wall can be manufactured.
This method is particularly suitable for producing thin and high-height metal cans.

In the above process, the impact molding is to mold the cup 11 by using the female die 21 and the punch 23 and impact-extrusion of the slag 3 in the die 21.
The outer diameter of the obtained cup 11 is the same as the diameter t ′ of the slag 3 (FIG. 1C).

In this method, the cup 11 can be used as a container as it is, and the bottom shape of the container can be various shapes according to the shapes of the die 21 and the punch 25, but the diameter and height of the container are limited. However, there is a limit to thinning, and there are also problems of surface roughness and surface smoothness. Therefore, the drawing process and the ironing process are performed in the next step, and thereby, the diameter can be reduced, the wall thickness can be reduced, and the surface gloss and the surface smoothness can be improved.

The above drawing can be performed directly on the slag 3 described above, but depending on the thickness of the slag 3 and the like, a severe surface pressure may be applied, which may make molding difficult. After that, it is desirable to reduce the diameter of the cup by drawing (redrawing).

In such drawing, as shown in FIG. 1D, a die 25 having an opening 25a having a diameter t1 (t1 <t ′) is used, a drawing punch 27 is used, and the cup 11 is removed. By pushing into the opening 25a of the die 25, a bottomed cylindrical drawn body 13 is obtained. The outer diameter of the drawn body 13 obtained by this drawing is equivalent to the diameter t1 of the opening 25a and is smaller than the diameter t 'of the cup 11 (or slag 3).

In the above-described drawing, a rounded portion (curvature portion) is formed at the corner portion (the side holding the cup 11) of the upper end of the opening of the die 25, and the cup 11 is not quickly and bent. The die 25 is pushed into the opening 25a, and the outer diameter of the drawing punch 27 is set smaller than the diameter t1 of the opening 25a by an amount corresponding to the thickness of the cup 11. In other words, thinning is hardly performed in this drawing process.
Such redrawing is performed a plurality of times as necessary, and further diameter reduction can be performed.

The drawn compact 13 thus obtained is subjected to ironing as shown in FIG. 1 (e).

In this ironing, the punch 31 for ironing is inserted into the above-mentioned bottomed cylindrical drawn compact 13, and the punch 31 is pressed against the inner surface of the ring-shaped die 33 while pressing the outer surface of the drawn compact 13. Is lowered, the side wall of the drawn molded body 13 is made thinner by the die 33. As a result, a metal container (squeezed and squeezed can) 5 having an outer diameter of the cup smaller than t1 and a height increased according to the degree of thinning is obtained.
Such ironing can be performed in a plurality of stages depending on the thinness and height of the target metal container 5. Note that the drawing punch 27 and the ironing punch 31 can be shared, and redrawing and ironing can be continuously performed in the same process.

The metal container 5 obtained by such ironing is not only thin and high in height, but also excellent in surface smoothness and gloss as compared with, for example, a conventionally known impact molded can. Further, by using pure aluminum having an aluminum content of 99.0% by mass or more as the metal material, the corrosion resistance is also improved.

The metal container 5 obtained as described above is subjected to dome molding, trimming, inner / outer surface coating, outer surface printing, decorative processing, neck-in processing, etc., as necessary, and the contents Are filled in and attached to the lid, and are put on the market.
Furthermore, the metal container 5 obtained as described above can be used as a battery container member.

In the plastic working shown in FIGS. 1C to 1E, for example, it is preferable to use a lubricant emulsion as a coolant, and in ironing, a known cemented carbide die 33 is used. Furthermore, it is possible to use a die 33 in which a hard film such as a diamond film is formed on the processed surface. Thereby, adhesion of metal materials, such as aluminum, to the surface of the die | dye 33 can be avoided effectively, and especially the smoothness and glossy metal container 5 of a surface can be obtained.

In such a manufacturing method of the present invention, since the round rod 1 is used as a starting material, the material loss is extremely small, which is the greatest advantage of the present invention.
In the production method of the present invention, the cross-sectional shape of the rod 1 is not limited to a circle, and can be appropriately selected depending on the shape of the metal container required.

The present invention will be described in the following experimental example.

<Experimental example 1>
A rod made of pure aluminum A1070 (20 mm diameter, 4 m length) with an aluminum content of 99.7% by mass or more is prepared, and this rod is cut and pressed to a length of about 20 mm, the diameter is 48 mm, the thickness Obtained a disk-shaped slag of about 3.5 mm.
This disk-shaped slag was annealed at 350 ° C. for 1 hour, and then impact molding was performed. The bottom diameter was 48 mm, the bottom thickness was about 0.9 mm, the average side wall thickness was about 1.3 mm, and the height was about 27 mm. A cup was molded. In molding, an aqueous emulsion was used as a lubricant. The side wall of this cup had rough skin peculiar to impact molding.
Next, the cup obtained above is redrawn using the same lubricant as described above, and a bottomed cylindrical drawing having a bottom diameter of about 36 mm, a side wall thickness of about 1.4 mm, and a height of about 38 mm. A molded body was obtained.
Further, using the same water-based emulsion coolant as above and using an ironing die having a diamond film formed on the processed surface, ironing is performed in three stages, with a bottom diameter of about 35 mm and a side wall thickness of about 0.1 mm. A pure aluminum drawn iron can having a height of 35 mm and a height of about 150 mm was obtained.

The obtained squeezed iron can was excellent in surface smoothness and gloss.
Furthermore, using the remaining pure aluminum rod after the molding, a pure aluminum drawn iron can was repeatedly molded by the same operation. As a result, 99% of the previously prepared pure aluminum rod can be used in the production of a pure aluminum drawn iron can, and material loss can be effectively avoided.

<Experimental example 2>
The same rod as in Experimental Example 1 is cut and pressed so as to have a length of about 17 mm, and the thickness is about 3 by changing only the pressing position of the press so that the diameter is 48 mm and the same slag diameter as in Experimental Example 1 is obtained. A disc-shaped slag of 0.0 mm was obtained.
This disk-shaped slag was annealed at 350 ° C. for 1 hour, and then impact molding was performed. The bottom diameter was 48 mm, the bottom thickness was about 0.9 mm, the side wall average thickness was about 1.3 mm, and the height was about 22 mm. A cup was molded. In molding, an aqueous emulsion was used as a lubricant.
Next, the cup obtained above was redrawn using the same lubricant as described above, and a bottomed cylindrical draw having a bottom diameter of about 36 mm, a side wall thickness of about 1.4 mm, and a height of about 32 mm. A molded body was obtained.
Further, ironing was performed in three stages under the same conditions as above to obtain a pure aluminum drawn ironing can having a bottom diameter of about 35 mm, a side wall thickness of about 0.35 mm, and a height of about 127 mm.

The obtained squeezed iron can was excellent in surface smoothness and gloss as in Experimental Example 1.
Compared with Experimental Example 1, simply changing the cutting length of the rod and the pressing position of the press for producing the slag can produce cans with different heights of pure aluminum drawn and ironed cans, making it easy to change the type of can became.

1: Metal rod 3: Slag 5: Metal container 11: Cup 13: Drawing molded body

Claims

Preparing a metal rod;
Cutting the rod at a constant height to produce a container slag;
Plastically processing the container slag into a container shape;
Of metal containers containing
The method for producing a metal container according to claim 1, wherein the rod is made of aluminum or aluminum alloy.
The method for producing a metal container according to claim 2, wherein the rod is made of pure aluminum having an aluminum content of 99.0% by mass or more.
The method for producing a metal container according to claim 1, wherein the plastic working is performed by at least one molding means selected from the group consisting of impact molding, drawing, redrawing and ironing.