JP2790072B2 - Manufacturing method of seamless cans - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a seamless can for forming a container body used for a carbonated beverage can, a beer can, a coffee beverage can, a fruit beverage can and the like.

[0002]

2. Description of the Related Art A method of manufacturing a relatively long and thin seamless can having a thinner side wall by re-drawing a metal drawing cup coated with an organic film using a die having a small radius of curvature at a processing corner. It has been proposed (JP-A-1-258822, JP-A-3-155419). In this method, since the thickness is reduced only by bending and stretching, there are the following problems. Breaking limit of thinning: In order to increase the can height by increasing the thinning, it was necessary to use a soft metal blank or to increase the number of times of redrawing. In the former, the buckling resistance and the bottom pressure resistance of the seamless can are reduced due to the softening of the side wall and the bottom, and in the latter, the equipment cost and the operating cost are increased due to the increase in the number of steps. It is not possible to control the thickness of the side wall portion: generally, the main portion of the side wall portion is uniformly thin and the vicinity of the opening portion is relatively relatively thick because of reduction of material cost and strength of the flange portion. It is desirable to control the thickness of the test piece (see the curve of test No. 1 in FIG. 21 ). However, in the case of the conventional method, the height-direction thickness distribution of the side wall portion is governed by the height-direction thickness distribution of the side wall portion of the drawing cup in the previous process, and cannot be controlled. (Test N in FIG. 21 )
o. See curve 10). Further, thickness fluctuation in the circumferential direction is relatively large due to anisotropy of the material. Deterioration of the organic film: Since the degree of uniaxial stretching is large, when the neck-in processing or the flange processing is performed in a later step, phenomena such as whitening are likely to occur in the organic film.

[0003]

SUMMARY OF THE INVENTION According to the present invention, a metal cup whose inner and outer surfaces are coated with an organic film has an improved breaking limit for reducing the thickness of the side wall, and the thickness distribution of the side wall can be controlled.
Moreover, it is an object of the present invention to provide a method for producing a relatively elongated seamless can in which the organic film hardly deteriorates such as whitening during post-processing such as neck-in processing, the side wall portion is thinned.

[0004]

The method for manufacturing a seamless can according to claim 1 of the present invention uses a punch, a wrinkle presser and a die from a metal cup whose inner and outer surfaces are coated with an organic coating. In a method of manufacturing an elongated seamless can, a punch is advanced into a cavity of a die while a wrinkle presser is inserted into a metal cup, and a bottom of the metal cup is pressed against a flat surface of the die with the wrinkle presser. While the outer surface is closely contacted with the die flat surface and the processing corner having a small radius of curvature of the die, the thickness of the side wall portion is reduced by bending and stretching at the processing corner, and the punch and the front end or front end of the processing corner are further reduced. By cooperating with the ironing portion consisting of the connecting short cylindrical portion, the thickness of the side wall portion is further reduced, and at least 5% is provided on the side wall portion to be the open end of the seamless can. Line Tsu name the ironing of ironing rate
To form a metal cup into a seamless can, and
Before working, heat the die, wrinkle holder and punch,
Switch heating to cooling just before starting molding, and continue cooling during molding
Contacts the sidewall of the metal cup of the die being formed
Surface temperature Td of the part, facing the die flat part of the wrinkle holder
Surface temperature Ts of the part to be removed and punch table immediately after extraction
The surface temperature Tp is set to the glass transition temperature of the organic film Tg + 50 ° C.
Below, each appropriate temperature within the temperature range of 10 ° C or more
It is characterized by keeping . In the present specification, the ironing portion is a gap between the die and the punch (so-called clearance).
Of the die in the radial direction, that is, the portion of the inner surface of the die that protrudes most toward the cavity. Open end of the seamless can (20) (20b; see FIG. 1)
The term “open” means a neck-in part and a flange part 21d (see FIG. 2) which are formed by neck-in processing and flange processing. The thickness of the opening end portion may be slightly thicker than the trunk main portion (20a; see FIG. 1), slightly thinner (see FIG. 6), or substantially equal to the trunk main portion depending on the application.

According to the method for manufacturing a seamless can according to claim 2 of the present invention, a relatively elongated seamless can is manufactured from a metal cup whose inner and outer surfaces are coated with an organic film using a punch, a wrinkle presser, and a die. In the method, the punch is advanced into the cavity of the die while the bottom of the metal cup is pressed against the plane of the die while the bottom of the metal cup is pressed against the plane of the die by the wrinkle holder, and the outer surface of the side wall of the metal cup is moved to the plane of the die. Part, the thickness of the side wall part is reduced by bending and stretching at the processing corner while being in close contact with the processing corner having a small radius of curvature of the die, and then the side wall part is advanced diagonally slightly inward in the cavity to form the punch and the die. By cooperating with the ironing part, the thickness of the side wall part is further reduced, and at least 5% of the ironing rate is added to the side wall part to be the open end of the seamless can. Engineering a row Do I, seam metal cup
Dies and wrinkle press before the above molding work
Heat the fixture and punch, and cool immediately before starting molding
To the die, keep cooling during molding,
Surface temperature Td, wrinkles at the part in contact with the side wall of the metal cup
Surface temperature T of the part of the holder that faces the die plane
s and the punch surface temperature Tp immediately after withdrawal are determined by organic coating.
The glass transition temperature Tg of the film is not higher than + 50 ° C. and not lower than 10 ° C.
It is characterized in that it is maintained at each appropriate temperature within the temperature range .

According to a third aspect of the present invention, there is provided a method for manufacturing a seamless can, comprising: a punch having a front portion from a metal cup whose inner and outer surfaces are coated with an organic coating, and a reduced diameter portion having a diameter slightly smaller than the front portion behind the metal cup. Using a wrinkle retainer and a die, a method for manufacturing a seamless can having a relatively elongated body portion, a body main portion, and an opening end portion having an inner convex portion and an outer convex portion slightly thicker than the body main portion. Then, while inserting the wrinkle holder into the metal cup and pressing the bottom of the metal cup against the plane of the die with the wrinkle holder, the punch is advanced into the cavity of the die, and the outer surface of the side wall of the metal cup is exposed to the die plane. While maintaining close contact with the processing corner where the radius of curvature of the die and the die is small, the thickness of the side wall is reduced by bending and stretching at the processing corner, and furthermore, the front side of the punch and the front end or front end of the processing corner are contacted. The thickness of the side wall portion is further reduced by the cooperation of the rear ironing portion consisting of a continuous short cylindrical portion and the front ironing portion having a smaller inside diameter than the rear ironing portion provided in front of the rear ironing portion, thereby further reducing the thickness of the side wall portion. And forming an open end by ironing at least 5% on a side wall portion to be an open end by cooperation of the reduced diameter portion of the punch and the rear ironing portion.

According to a fourth aspect of the present invention, there is provided a method for manufacturing a seamless can, comprising: a punch having a front portion from a metal cup whose inner and outer surfaces are coated with an organic coating, and a reduced diameter portion having a diameter slightly smaller than the front portion behind the metal cup. Using a wrinkle retainer and a die, a method for manufacturing a seamless can having a relatively elongated body portion, a body main portion, and an opening end portion having an inner convex portion and an outer convex portion slightly thicker than the body main portion. Then, while inserting the wrinkle holder into the metal cup and pressing the bottom of the metal cup against the plane of the die with the wrinkle holder, the punch is advanced into the cavity of the die, and the outer surface of the side wall of the metal cup is exposed to the die plane. Part, the thickness of the side wall part is reduced by bending and stretching at the processing corner while making close contact with the processing corner with a small radius of curvature of the die, and then the side wall part is advanced diagonally inward in the cavity, and the rear part Contacting the ironing portion, and a punch front portion, and reduce more the thickness of the side wall portion by cooperation with the rear ironing portion and inner diameter than the rear ironing portion provided in front of the rear ironing portion is smaller front ironing unit cylinder Forming an opening end portion by forming an opening end portion by forming at least a 5% ironing rate on a side wall portion to be an opening end portion in cooperation with the reduced diameter portion of the punch and the rear ironing portion. And In the case of the invention according to claim 1, 2, 3, or 4, the ratio Rd / t0 of the radius of curvature Rd of the processing corner to the blank thickness t0 of the metal cup is preferably 1 to 2.9 (claim). 5 ). Invention according to claim 3 or 4
In the case of, the inside of the die, the wrinkle presser and the punch is heated before the forming operation, the heating is switched to cooling immediately before the start of the forming, and the cooling is continued during the forming , and the side of the metal cup with the dies being formed is cooled. The surface temperature Td of the contacting part, the surface temperature Ts of the part facing the die flat part of the wrinkle retainer, and the punch surface temperature Tp immediately after the extraction are set to a temperature of 10 ° C. or higher at the glass transition temperature Tg of the organic film + 50 ° C. or lower it within the range of
It is preferable to maintain the appropriate temperature (claim 6 ).

[0008] The field of the invention according to claim 1, 2 or 6
In case, a through hole is provided in the die, wrinkle holder and punch,
Warm water into dies, wrinkle retainers and punches before molding.
Switch from hot water to cold water just before molding starts
Continue flowing medium-cooled water into dies, wrinkle retainers and punches
(Claim 7). Claims 1, 2, 3,
In the case of the invention according to 4, 5, or 6, the organic coating is linear.
It is preferable to use a polyester film (claim
Item 8). Case of the invention according to claim 2 or 4, (in the case of claims 4 rear ironing portion and the front ironing part) ironing portion of the die leading to, approach surface extending obliquely slightly inward, forming a center axis of the die an approach angle α is 1 to 5 degrees, approach surface and the ironing portion, it is preferable that the connected via a curved portion of the sharp corner or 0.3xt0 smaller curvature radius Ri, (claim 9). The approach surface extending diagonally slightly inward to the ironing portion of the die is composed of a rear approach surface and a front approach surface, and the approach angle α of the rear approach surface, which is the axis of the die, is 1 to 15 degrees. The approach angle γ that forms the axis of the die on the front approach surface is 1 to 5 degrees, and the approach angle α is larger than the approach angle γ, and the rear approach surface and the front approach surface, and the front approach surface and the ironing portion Are preferably connected via a sharp corner or a curvature portion having a curvature radius Ri smaller than 0.3 × t0 (claim 10 ).

In the case of the invention according to claim 2 or claim 4 , the dice of the approach surface extending slightly obliquely inward to the ironing portion of the die (the rear ironing portion and the front ironing portion in the case of claim 4 ). Is 1 to 45 degrees, and the approach surface and the squeezed portion are (0.
It is preferable that the connected via a curved portion of the curvature radius Ri of 3 to 20) xt0 (claim 11).

In the case of the invention according to claim 2 or 4 ,
The ironing part of the die (the rear ironing part and the front ironing part in the case of claim 4 ) is a short cylindrical shape (claim 12).
Or a circumferential line is preferable (claim 13). When the ironing part is a short cylindrical shape, its height is usually 5 mm or less. In the case of the invention according to claim 1, 2, 3 or 4, the cavity extends slightly obliquely outward in front of the ironing portion (the rear ironing portion and the front ironing portion in the case of claim 3 and claim 4 ). It is preferable to provide a flank with a clearance angle β of 5 degrees or less with respect to the axis center of the (claim 14).

[0011]

In any of the inventions according to the first, second, third, and fourth aspects, since the radius of curvature of the processing corner of the die is small, the side wall of the metal cup is bent and stretched at the processing corner. Is thinned. Although ironing is performed after bending and stretching at the processing corner, the force applied during bending and stretching is in the height direction of the side wall portion, whereas in the case of ironing, the force is in the thickness direction. In general, the breaking limit is improved by ironing, but by applying ironing to bending and stretching in different directions to which force is applied, it is possible to realize significant thinning from the synergistic interaction of the two forces. . Thus, relatively elongate seamless cans, preferably having a height / diameter ratio of 1 or more, can be produced. In the ironing process, the side wall portion is passed through the gap between the punch and the ironing portion, is ironed, and is thinned to a thickness substantially equal to the gap width of the gap portion. By controlling the gap width in the vertical direction, the thickness of the side wall in the height direction can be controlled (see the curve of test No. 1 in FIG. 21 ). In addition, by making the gap width constant in the circumferential direction, the circumferential thickness of the side wall portion can be made uniform.

[0012] The organic film is thinned by uniaxial stretching in the height direction by redrawing.
Since the thickness is reduced while receiving the surface pressure in the thickness direction, the thickness distribution of the side wall becomes uniform unlike the case where only the redrawing is performed. It is considered that since the ironing process with an ironing rate of at least 5% is applied to the side wall portion to be the opening end, local uneven deformation when the opening end is subjected to neck-in processing or flange processing is suppressed. However, deterioration such as whitening of the organic film in the neck-in portion hardly occurs. In addition, since the organic coating is smoothed by ironing, printability is improved.

A seamless can for a positive pressure can such as a carbonated beverage can has an extremely thin main body, so that the opening end is not easily cracked by processing when neck-in processing is performed later. It has a predetermined thickness slightly thicker than the main part (see paragraph number 0027). Conventionally, such thickening of the opening end portion is performed only by providing a reduced diameter portion on the punch, ironing the opening end portion in contact with the reduced diameter portion, and attaching an inner convex portion. (See paragraph number 0023; FIG. 3). In this case, especially when the thickness difference between the trunk main portion and the opening end portion is relatively large (that is, when the inner convex portion is relatively high),
Even if there was a tapered portion between the two, it was easy to make it difficult to extract the punch. In the case of the invention according to claims 3 and 4 , an open end is formed between the rear ironing portion (for example, 3b1 in FIG. 4 or 3g in FIG. 7) and the front ironing portion (23a in FIG. 17 ). Outer convex portions are formed simultaneously with the convex portions.
Therefore, even when the thickness of the main body portion is considerably thinner than the thickness of the opening end portion, the height of the inner protruding portion can be made relatively low, so that the punch can be easily extracted. The appearance is slightly worse if only the outer protrusions are used, but the outer protrusions can be lowered by the amount of the inner protrusions, so that the appearance is not impaired to the left. In the case of the invention of claim 5 , since Rd / t0 is 1 to 2.9, it is possible to realize thinning by bending and stretching without breaking the side wall portion. If Rd / t0 is less than 1, the degree of bending elongation becomes too large to cause breakage, and if it is more than 2.9, the degree of bending elongation is small and thinning hardly occurs.

The inventors have found that the coefficient of kinetic friction between the die, punch and wrinkle holder and the organic coating is reduced between 10 ° C. and the (glass transition temperature Tg + 50 ° C.) of the organic coating. In view of this phenomenon, claims 1, 2 and 6
For the invention, the die during molding, the surface temperature Td of the portion in contact with the side wall of the metal cup, the surface temperature of the die planar portion facing the portion of the wrinkles retainer Ts, and extraction immediately after the punch surface temperature Tp ( Immediately after molding, that is, substantially equal to the surface temperature immediately before ejection), the glass transition temperature Tg of the organic film is equal to or lower than + 50 ° C.
Since the respective temperatures are appropriately set, the sliding friction resistance between the organic coating and the die and the wrinkle presser during the molding is relatively small, and therefore, the collapse due to the large sliding friction resistance is unlikely to occur. Also, the punch after molding can be easily removed from the seamless can. If the surface temperatures Td, Ts, and Tp are higher than the above (glass transition temperature Tg + 50 ° C.), the organic coating softens during molding, and the outer organic coating is scraped off during ironing, or the punch is seamlessly removed. At the time of extraction from the inside, troubles such as the inner organic coating being in close contact with the punch and the inner organic coating being destroyed are likely to occur. If the surface temperatures Td, Ts, and Tp are lower than 10 ° C., the sliding friction resistance on the wrinkle-pressing surface, the processing corner, or the like becomes large, so that it is easy to cause a broken body or a failure in removing the punch.

The control of the surface temperatures Td, Ts and Tp is performed by heating the inside of the die, the wrinkle presser and the punch before the molding operation, switching the heating to cooling immediately before the start of molding, and continuing to cool during molding. Performed , more specifically,
Form through holes in dies, wrinkle retainers and punches and mold
Warm water flows through dies, wrinkle retainers and punches before work
Immediately before the start of molding, switch the hot water to cold water
Keep water flowing through dies, wrinkle retainers and punches
(Claim 7). When the metal cup is inserted into a tool whose dies, wrinkle holders and punches are at room temperature (for example, about 5 ° C. in the case of midwinter) and molding is started, the temperature of the organic film is lower than 10 ° C. and the dynamic friction coefficient is high. It is conceivable, however, that a broken body occurs or the punch cannot be removed from the molded seamless can, so that the subsequent molding operation becomes impossible. However, the inside of the die, the wrinkle presser and the punch was heated to a temperature suitable for the characteristics of the organic film, with the surface temperatures Td, Ts, and Tp being 10 ° C. or more, and heating was performed immediately before the start of molding. When the temperature is switched to cooling and molding is started, the surface temperature Td, Ts, Tp is an appropriate temperature of 10 ° C. or more at the moment of the start (when the first metal cup is molded). You can start.

At the time of forming, a very large force is applied to a portion of the die that contacts the side wall of the metal cup, a portion of the wrinkle holder that faces the plane of the die, and a portion of the punch that contacts the side wall of the metal cup. The processing heat and frictional heat of the material in these parts and in the vicinity thereof are transferred to the dies, wrinkle holders and other parts of the punch, and as the number of molding increases, the temperature of the dies, wrinkle holders and punches as a whole increases. Gradually rise. However, by continuing cooling during molding,
The surface temperatures Td, Ts, and Tp can be set to appropriate temperatures within a temperature range of 10 ° C. or higher at a glass transition temperature Tg + 50 ° C. or lower of the organic film.

In the case of the die according to the ninth aspect, since the approach angle α of the approach surface reaching the ironing portion is as small as 5 degrees at the maximum, the curvature of the approach surface and the ironing portion is a sharp corner or a curvature radius Ri smaller than 0.3 × t0. Even if they are connected via the portion, the load applied to the connected portion during ironing is relatively small, so that the outer organic film is hardly shaved. If the approach angle α is smaller than 1 degree, the ironing surface pressure (the force pressing the die outward) increases, and the die elastically deforms so that the inner surface of the die faces outward in the radial direction. Since the width of the gap between the punch and the die becomes large, it becomes difficult to obtain a predetermined ironing amount. Furthermore, when the punch is removed from the die, the die tries to return to the original gap width narrower than the insufficiently ironed plate thickness due to elastic recovery, and the cup is tightened against the punch from the outside, making extraction difficult .

In the case of the die according to the tenth aspect , as in the case of the die according to the ninth aspect, since the approach angle α of the front approach surface connected to the ironing portion is as small as 5 degrees at the maximum, the approach surface and the ironing portion Are connected via a sharp corner or a curvature portion having a radius of curvature Ri smaller than 0.3 × t0, the load applied to the connection portion is relatively small, so that the outer surface organic coating is less likely to be shaved during ironing. Even if the rear approach surface and the front approach surface are connected via a sharp corner or a curvature portion having a radius of curvature Ri smaller than 0.3 × t0, this portion, which is the initial stage of ironing deformation, is added to the connection portion during ironing. Since the load is still relatively small, the outer organic coating is hardly abraded. In the case of the die according to the tenth aspect, the approach surface is divided into a rear part and a front part, so that the rear approach angle α can be increased up to 15 degrees as compared with the approach angle of the die according to the ninth aspect . When the approach angle is appropriately increased, the outer organic coating is less likely to be scraped, and the punch is more easily extracted.

In the case of the die according to the eleventh aspect , the radius of curvature Ri can be increased to (0.3 to 20) × t0, and the range of the approach angle α can be further increased to 1 to 45 degrees. Since Ri is relatively large as described above, stress concentration on the ironed portion is relatively small, so that the outer organic film is hardly shaved. Therefore, by appropriately setting the approach angle α within the range of 1 to 45 degrees, it is possible to obtain a desired ironing rate without shaving the outer surface organic coating during ironing, and to remove the punch. It will be easier.

When the approach angle α exceeds 45 degrees,
Excessive load becomes too large, and crushing of the body and organic coating on the outer surface
Is more likely to occur. Curvature radius Ri exceeds 20xt0
And the range of apparently small tangent angles becomes longer,
Due to the wedge action, the inner surface of the die is
The die is elastically deformed so as to face outward in the radial direction,
Since the gap width between the die and the die becomes large,
It is difficult to obtain, but in this case,
Therefore, such troubles are unlikely to occur.

In the case of the die according to the fourteenth aspect, a relief surface having a maximum relief angle β of 5 degrees is provided in front of the ironing portion. Therefore, when the seamless can is extracted from the die, the contact length between the die and the seamless can is shortened, and the extraction is facilitated. If the clearance angle β exceeds 5 degrees, the removal of the outer organic film tends to occur when the seamless can is pulled out.
In this case, since it is 5 degrees or less, the outer organic film is hardly scraped.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which thinning redrawing and ironing are performed with the same tool, that is, with the same stroke, will be described. 3 and 4 (corresponding to claim 1), reference numeral 1 denotes a punch attached to a punch plate (not shown);
Reference numeral 2 denotes a wrinkle retainer which surrounds the punch 1 with a slight gap 8 and is attached to the upper die shoe coaxially with the punch 1.
Is a die mounted on a lower die shoe (not shown) coaxially with the punch 1 by a die holder 4. Reference numeral 6 denotes an annular bending member for forming a reduced diameter portion by bending repeatedly below the side wall portion 5b immediately before the forming of the metal drawing cup 5, and is coaxial with the punch 1 on the plane portion 3a of the die 3. It is fixed.

The punch 1 is, as shown in FIGS. 3 and 5, a neck-in portion 21c of the body of the seamless can 20 to be formed.
A portion (see 20b in FIG. 1) corresponding to a portion that should become the flange portion 21d (see FIG. 2) is the body main portion 2
A reduced diameter portion 1b having a slightly smaller diameter than the front portion 1a corresponding to the portion 0a via the tapered portion 1b1. As shown in FIG. 4, the die 3 has a flat flat portion 3a which is the upper surface, a processing corner 3b having a small radius of curvature Rd connecting the flat portion 3a and the peripheral surface of the cavity 7, and a lower end 3b1 (ironing portion) of the processing corner 3b. A flank 3e, flank 3e, which is connected and extends slightly obliquely outward and downward at a taper angle β with the axis of the cavity 7.
A frustoconical portion 3f extending obliquely outward and downward at a much larger angle is provided. Curvature radius Rd of machining corner 3b
Is (1-2.9) × t0 (t0 is the thickness of the blank: FIG. 1,
See). The clearance angle β is set to a maximum of 5 degrees. In FIG. 4, the relief angle β is illustrated assuming that the outer surface of the side wall after ironing is parallel to the axis of the cavity 7. Front part 1a of punch 1 and machining corner 3
the lower end 3b1, ie, the gap 15 between the ironing portions 3b1
Is set substantially equal to the thickness of the main body portion 20a of the seamless can 20 to be formed. As shown in FIGS. 4 and 5, the opening end 20b where the neck-in portion is formed by the neck-in process is formed by the reduced-diameter portion 1b of the punch 1 and the ironing portion 3b1 of the die 3, and the body main portion 2b.
It is formed so as to protrude inward with respect to 0a and to be thickened.

The lower part of the wrinkle holder 2 has a flat holding surface 2
a, curved portion 2b, curved portion 2 connected to the outer end of holding surface 2a
b, a sloped portion 2d extending diagonally outward and connected to the upper end of the short cylindrical portion 2c, and a curved portion 2e connecting the sloped portion 2d and the cylindrical outer peripheral surface 2f of the wrinkle retainer 2. (FIG. 3), and the short cylindrical portion 2c and the inclined portion 2d cooperate to form a concave portion 2g having a rectangular shape in cross section. Therefore, the lower part of the wrinkle holder 2 is reduced in diameter. The portion of the annular bending member 6 facing the concave portion 2g is a curved portion 6a, and a portion between the concave portion 2e and the curved portion 6a is slightly smaller than the thickness t1 of the side wall portion 5b of the cup 5 to be processed. A gap 9 having a large gap width is formed. The outer diameter of the outer peripheral surface 2f of the wrinkle holder 2 is set to a size in which the aperture cup 5 is almost perfectly fitted. The punch 1 and the wrinkle presser 2 are moved up and down at a predetermined timing by a mechanism (for example, a crank mechanism or the like) not shown.

The cup 5 during molding shown in FIG.
A thin metal coating 12, for example, a linear polyester film is coated on both sides of a metal plate 11 for a can by heat bonding, and a pre-draw cup 13 (FIG. 1) formed from a circular blank 10 by drawing. For example, Japanese Patent Laid-Open No. 1-2
This is a redraw cup formed by thinning and redrawing according to a conventional method as described in Japanese Patent No. 58822 (FIG. 1). As metal plates for cans, tin-free steel, tin-plated steel plate, (electric) galvanized steel plate, nickel-plated steel plate, aluminum (alloy) thin plate, etc. having a thickness of 0.1 to 0.5 mm are used for cans, sizes, etc. It is used according to.

A redraw cup 5 in which a lubricant, for example, paraffin wax (melting point: 60 ° C.) is thinly applied to the inner and outer surfaces.
Using the above-described apparatus, the seamless can 20 is manufactured as follows. A redraw cup 5 placed on the die 3 or near the upper part of the curved portion 6a of the annular bending member 6
(This state is not shown), wrinkle presser 2 is fitted,
The punch 1 is advanced into the cavity 7 of the die 3 (FIG. 3). Since the wrinkle holder 2 also advances, the side wall 5b of the squeeze cup 5 is bent inward along the curved portion 2e, reversely bent along the curved portion 6a, and bent by the wrinkle retainer 2 and the annular bending member 6. It undergoes internal bending and repeated bending along 2b. Next, the side wall portion 5b is bent at a large curvature at the processing corner 3b of the die 3 while being pressed to such a degree that wrinkles do not occur between the plane portion 3a of the die 3 and the pressing surface 2a of the wrinkle pressing device 2, Ironing is performed by cooperation between the ironing portion 3b1 and the punch 1.

When the side wall 5b passes through the processing corner 3b,
It receives a relatively large reverse tension due to the above-mentioned repeated bending and wrinkle holding force. The side wall portion 5b is stretched while being subjected to relatively large reverse tension at the machining corner 3b having a small radius of curvature while being bent while being bent at a large curvature, and then the gap width is formed by cooperation between the ironing portion 3b1 and the punch 1. Undergoes ironing while passing through the gap 15 at t3. That is, the side wall portion is subjected to bending and stretching until the inner surface comes into contact with the punch 1 so that the wall thickness decreases from t1 to t2, and the contact portion 5x
After the contact, ironing is performed and the wall thickness at the ironed portion 3b1 further decreases to t3. At least 5%, preferably 10 to 10%, of the open end portion 20b formed of a thick portion protruding inward where the neck-in portion is formed by the neck-in process.
Ironed at 40% ironing rate. In this case, the drawing thinning rate is defined as (t1-t2) * 100 / t1%, and the ironing rate is defined as (t2-t3) * 100 / t2%. As shown in FIG. 5, the punch 1 is advanced to reduce the thickness of the redrawing cup 5 until the flange portion 20c corresponding to the flange portion 5c (see FIG. 1) of the redrawing cup 5 comes on the die flat portion 3a. , The trunk main portion 20a is significantly thinned (the opening end portion 20b is relatively thick) and relatively elongated, that is, the ratio of height / trunk outer diameter is 1 or more, and the trunk outer surface has Is cylindrical over its entire length,
A seamless can 20 having 0c (see FIG. 1) is manufactured.

Extraction of the punch 1 from the state of FIG. 5 is performed as follows. With the wrinkle holder 2 fixed,
The die 3 is lowered below the bottom 20d of the seamless can 20, and at the same time, the air guide hole 1c provided in the punch 1 is provided.
The punch 1 is raised while blowing air 16 through the punch. When this rise, the flange portion 20c of the seamless can 20
Is pressed by the wrinkle presser 2 and stays at the position shown in the drawing, so that the punch 1 is pulled out of the seamless can 20.

As shown in FIG. 6, there is also a seamless can 20 'having a thick portion 20'a1 protruding inward along the vicinity of the center of the body portion 20'a and having a length substantially equal to 1/3 of the total height. ,
The punch 1 can be manufactured in the same manner as described above except that the portion corresponding to the thick portion 20a'1 is a reduced diameter portion. This type of seamless can 20 ′ has a trunk 20 ′ a
Since the dent strength is relatively high, it is suitable for so-called negative pressure canning where the inside has a negative pressure. Although not shown, a seamless can having the same thickness at the main body portion and the opening end portion can be manufactured by using a punch having the same outer diameter over the entire length. This type of seamless can and the seamless can 2 shown in FIG.
0 'can also be manufactured using a die described in paragraph numbers 0035 to 0040 described below and a punch of the type described above.

The thickness reduction due to the redrawing is caused by the processing corner 3b
Is larger as the radius of curvature Rd of is smaller. Ratio Rd / t0 of radius of curvature Rd to thickness t0 of blank 10 (FIG. 1)
Is desirably 1 to 2.9. If it is smaller than 1, the degree of bending and stretching becomes too large, and breakage is likely to occur. On the other hand, if it is larger than 2.9, it is difficult to reduce the thickness. By providing the flank 3e with the clearance angle β, it is easy to remove the seamless can 20 after molding. However, it is not preferable that the clearance angle β exceeds 5 degrees, since the outer organic film 12 is easily scraped off during extraction. Although not shown, the processing corner 3
A short cylindrical portion connected to the lower end 3b1 may be provided between the lower end (that is, the front end) 3b1 and the flank 3e of b, and this short cylindrical portion may be used as an ironing portion. The height of the short cylinder is 5mm
The following is preferred.

The surface temperature Td of the portion of the die 3 in contact with the side wall portion 5b during molding, that is, the surface temperature Td of the flat portion 3a and the processing corner 3b is determined by the glass transition temperature Tg +
50 ° C. or lower, and 10 ° C. or higher, more preferably Tg +
The temperature is preferably 30 ° C. or lower and 15 ° C. or higher. When the surface temperature is higher than Tg + 50 ° C., the coefficient of sliding friction of the organic coating 12 is increased, and the organic coating 12 is softened, and the outer organic coating 12 is shaved at the time of molding, particularly at the time of ironing. This is because it cannot be obtained. On the other hand, if the temperature is lower than 10 ° C., it is considered that the sliding friction resistance between the die 3, especially the flat portion 3 a and the outer organic coating 12 is large, but the die is easily broken. For the same reason, the surface temperature Ts of the pressing surface 2a of the wrinkle holder 2 is also an appropriate temperature of 10 ° C. or higher , more preferably Tg + 30 ° C. or lower, and 15 ° C. or higher , of the glass transition temperature Tg + 50 ° C. or lower of the organic film 12. Is preferred. Punch surface temperature Tp immediately after extraction
The glass transition temperature Tg of the organic film 12 is not higher than 50 ° C., and is not lower than 10 ° C., more preferably not higher than Tg + 30 ° C.
It is preferable that the temperature be an appropriate temperature of 5 ° C. or higher. If the surface temperature is higher than Tg + 50 ° C., the sliding friction coefficient of the coating increases, and the coating softens, and when the punch 1 is pulled out from the seamless can 20, the inner organic coating 12 is shaved to obtain a satisfactory product. This is because it will not be possible. On the other hand 10
If the temperature is lower than 0 ° C., the sliding friction coefficient between the surface of the punch 1 and the organic coating 12 increases, so that it is difficult for the punch 1 to come off.

As the organic film 12, a linear polyester film, for example, a copolymer resin film containing about 70 mol% or more of ethylene terephthalate or a blend resin film containing about 70 mol% or more of polyethylene terephthalate is used. Particularly preferably used ethylene terephthalate / ethylene isophthalate copolymer (mol ratio: 88/12, crystal melting point:
(230 ° C., glass transition temperature Tg: 70 ° C.) In the case of a film, Tg + 50 ° C. becomes 120 ° C.

The production of the seamless can 20 is usually performed continuously using a transfer press. In this case, the surface temperatures Td, T of the die 3, the wrinkle presser 2 and the punch 1
In order to set s and Tp to appropriate temperatures within the above temperature range, the following method is preferably adopted. A through-hole (not shown) is provided in the die 3, the wrinkle presser 2 and the punch 1. For example, hot water (preferably about 40 to 85 ° C.) flows through the die 3 before the molding operation. Is added to, for example, cold water (about 5 to 30C, more preferably about 12 to 18C).
° C) and keep flowing cold water during molding. That is, at the start of molding, the surface temperatures Td, Ts, and Tp of the die 3, the wrinkle presser 2, and the punch 1 are set to 1 by flowing hot water in advance.
Keep at 0 ° C or higher. When molding is started, the surface temperatures Td, Ts, and Tp increase due to processing heat, frictional heat, and the like. This temperature rise is suppressed and the surface temperatures Td, Ts, and T
In order to make p equal to or lower than Tg + 50 ° C., cold water flows through the die 3, the wrinkle presser 2, and the punch 1.

After the chime portion 21a and the dome portion 21b are formed in the seamless can 20, the upper portion of the side wall portion (the portion approximately 5 mm below the flange portion 20c) is cut together with the flange portion 20c, as shown in FIG. A neck-in portion 21c and a flange portion 21d are formed at the opening end portion 20b to form a container body 21 used for canning carbonated beverage cans and the like.

Another embodiment in which thinning redrawing and ironing are performed in the same stroke will be described. The method shown in FIG. 7 (corresponding to claim 2) is a tool used in the method shown in FIG. 4 (corresponding to claim 1), in which the processing corner 3b of the die 3 and the short cylindrical ironing portion are used. 3g is the same except that the approach surface 3c is a truncated conical approach surface 3c and that the approach surface 3c is connected to the approach surface 3c via a connecting portion 3d of the ironing portion 3g. With the advance of the punch 1, the side wall portion 5b is bent and stretched by being bent at a large curvature while receiving a relatively large reverse tension at the processing corner 3b of the die 3, and the wall thickness is reduced from t1 to t2. After that, it advances a little obliquely inward along the approach surface 3c in the cavity 7 and cooperates with the front portion 1a of the punch 1 and the ironing portion 3g and the lower portion 3c 'of the approach surface 3c to form the ironing portion 3g and the punch 1 While passing through the gap 15 therebetween, the thickness is reduced from t2 to t3 to form the trunk main portion 20a. That is, the side wall portion 5b contacts the punch 1 before reaching the ironing portion 3g as shown. Thereafter, the opening end portion 20b is formed by ironing with a reduction ratio of at least 5%, preferably 10 to 40% by the cooperation of the reduced diameter portion 1b, the ironing portion 3g and the approach surface 3c of the punch 1.

While the side wall 5b is pulled slightly obliquely inward and downward while being in close contact with the approach surface 3c and the connecting portion 3d, the side wall 5b is subjected to an ironing process in cooperation with the punch 1 by the ironing portion 3g. Is a dice
The approach angle α between the cavity 7, that is, the axis of the punch 1 (in FIG. 7, the peripheral surface of the punch 1 is regarded as the axis) is preferably 1 to 5 degrees. At the same time, it is preferable that the connecting portion 3d is a sharp corner or a curvature portion having a radius of curvature Ri smaller than 0.3 × t0. The reason is as described in paragraph 0017. It is also preferable that the approach angle α of the approach surface 3c is 1 to 45 degrees, and at the same time, the connecting portion 3d is a curvature portion having a curvature radius Ri of (0.3 to 20) × t0. The reason is that paragraph number 0
019.

As shown in FIG. 8, the die 3 is mainly composed of a bending member 3x and an ironing member 3y which are fixed to each other, and the cavity peripheral surface below the processing corner 3b of the bending member 3x is obliquely downward and outward. The die 3 may be the same as the die 3 shown in FIG. 7 except that it is inclined and the annular recess 14 is formed. The portion between the lower end 3b1 of the processing corner 3b and the connecting portion 3d of the ironing member 3y becomes the approach surface 3c at the approach angle α. The side wall 5b does not come into contact with the die 3 at the concave portion 14, but there is no particular problem, and there is an advantage that manufacture and maintenance of the tool are easy.

As shown in FIG. 9, the approach surface 3c of the die 3 may be a curvature surface having a radius of curvature Rc which slightly protrudes toward the punch 1. In this case, the approach angle α is set between the lower end 3b1 of the machining corner 3b and the connecting portion 3b.
It is determined based on a straight line connecting d (upper end 3d1 when the connecting portion 3d is a curvature portion).

As shown in FIG. 10, in the die 3, the ironing portion 3g has only the connecting portion 3d (in the case of a sharp edge) or only the lower end of the connecting portion 3d (in the case of a curvature portion: (not shown)). 7, except that a flank 3e having a clearance angle β of 5 degrees or less is formed in front of the ironing portion 3g.

As shown in FIG. 11, the die 3 has an approach surface 3c composed of a rear approach surface 3c1 and a front approach surface 3c2, and the approach angle α between the rear approach surface 3c1 and the axis of the die is 1 to 15 degrees. And the approach angle γ (α> γ) between the front approach surface 3c2 and the axis of the dice is 1 to 5 degrees, and the rear approach surface 3c
1 and front approach surface 3c2, and front approach surface 3
7 except that c2 and the ironing portion 3g are connected via the sharp corners or the connecting portions 3d1 and 3d2 of the curvature portions having a radius of curvature Ri smaller than 0.3 × t0, respectively.
May be the same as the die 3 shown in FIG. In FIG. 11, the ironing portion 3g has a short cylindrical shape. However, as shown in FIG. 10, as in the case of the die 3, the ironing portion 3g may be composed of only the connecting portion 3d (in the case of a sharp edge) or only the lower end of the connecting portion 3d2 (in the case of a curvature portion). . Further, a clearance surface 3e having a clearance angle β of 5 degrees or less may be formed in front of the ironing portion 3g. 7 to 11, the temperature of the punch 1, the wrinkle holder 2, the die 3, and the annular bending member 6 is controlled as described in paragraph 0031.

FIGS. 12 and 13 show, for the participant, an example in which thinning redrawing and ironing are performed with separate tools, ie, two strokes. As shown in FIG. 12, a punch 31, a wrinkle presser 32, and a small radius of curvature Rd having substantially the same structure as the apparatus shown in FIGS. 3 and 7 except that the approach surface 3c and the ironing portion 3g are not provided. Redrawing die 3 having corner 33b and flank 33e
3 and the redrawing tool 30 provided with the annular bending member 36 and under the same redrawing conditions (the die surface temperature T
d), the punch 31 is advanced and the metal squeezing cup 5
Is redrawn to form a thinned redrawn cup 37 (FIG. 13) in which the thickness of the side wall portion 5b is reduced from t1 to t2. Next, as shown in FIG. 13, an ironing die 3 having a punch 34, an approach surface 35c having an approach angle α, a connecting portion 35d having a radius of curvature Ri, and an ironing portion 35g.
5 and under the same ironing conditions (such as die surface temperature) as in the case of one stroke.
At least 5 on the side wall to become the open end 20b.
%, Preferably 10 to 40%, and the thickness of the body main part 20a is t3.
0 is produced. The ironing portion may be of the type shown in FIGS. Approach angle α is 1 to 30 degrees
And the radius of curvature Ri is (0.3 to 20) × t0.
Is preferred. Also in this case, using the punches 31 and 34 having the same diameter over the entire length of the processing portion, the thickness of the main body portion and the opening end can be substantially turned to produce a seamless can, but the equipment cost increases. , And the number of processes increases
There is a disadvantage that the production cost is high .

Immediately after the thinning re-drawing and ironing shown in FIG. 3 or FIGS. 7 to 11, by further ironing with one stroke, as shown in FIG. It is possible to manufacture a seamless can 20 ″ having a large wall thickness by protruding outwardly from the body main portion 20 ″ a. FIG. 14 shows that the punch 1 ′ is a processing portion (in front of the punch 1 in FIG. 3). (Corresponding to the portion 1a and the reduced diameter portion 1b) except that the diameter of the processed portion is uniform over the entire length, that is, the processed portion is different from the punch 1 except that the punched portion 1 is a wrinkle presser 2, a die 3, and an annular bending member 6. However, for example, a thinning redrawing-ironing tool 22 similar to that shown in FIG. 3 and an ironing die arranged near the front of the die 3 and having an inner diameter of an ironing portion 23 a smaller than the inner diameter of the ironing portion of the die 3. 23 and metal drawing cup 5 The distance between the flat portion 3a of the die 3 and the ironing portion 23a of the ironing die 23 or the upper end thereof is the upper end 2 of the thick portion of the opening end 20 "b.
It is equal to the length between 0 "b1 and the lower end of the inclined portion 20" b2. The mode of the ironing portion 23a of the ironing die 23 is shown in FIGS.
1, any of those shown in FIG. The punch 1 'of the tool 22 is advanced, and at least 5%, preferably 10 to 4%, until the side wall 5b of the squeezing cup 5 has a predetermined thickness (thickness of the opening end 20 "b) by the die 3.
Thinning and redrawing to perform ironing at an ironing rate of 0%-Ironing is performed, and a flange portion 20 ″ c is formed by a die 23.
(Corresponding to the flange portion 5c) is the flat portion 3a of the die 3.
(FIG. 15) until the body part 20 ″ has a predetermined thickness.
Ironing is performed at an ironing rate of, for example, about 0.5 to 40% so that a can be obtained. Also in this case, the temperature of the punch 1 ′, the wrinkle holder 2, the dies 3 and 23, and the annular bending member 6 is controlled as described in paragraph 0031.

As shown in FIG. 3, except that a punch 1 having a front portion 1a and a reduced diameter portion 1b slightly smaller than the front portion 1a and a tapered portion 1b1 behind the front portion 1a is used. In the same way as in the method,
Immediately after the ironing, by further ironing in one stroke, the opening end 120b where the neck-in is formed by the neck-in processing as shown in FIGS. Thus, a seamless can 120 having a large thickness protruding outward and inward can be manufactured. In FIG. 20, the portion of the open end protruding outward from the trunk main portion 120a is the outer convex portion 120b1, and the portion of the open end protruding inward is the inner convex portion 120b1.
b2. The outer convex portion 120b1 is connected to the outer surface of the trunk main portion 120a via the inclined portion 120b3, and the inner convex portion 120b2 is connected to the inner surface of the trunk main portion 120a via the small gradient inclined portion 120b4. . In FIG. 20, the lower end 120b6 of the inclined portion of the outer convex portion 120b1 is connected to the inner convex portion 1b.
Although it is located slightly closer to the opening end than the lower end 120b7 of the inclined portion of 20b2, the positional relationship between the two is appropriately determined as necessary. FIG. 17 shows a punch 1, a wrinkle retainer 2, a die 3, and an annular bending member 6 similar to those shown in FIG. Metal squeezing cup 5 using die 23
Shows the state during molding. Ironing part 2 of ironing die 23
3a is preferably in the form shown in FIGS. The inner diameter of the ironing portion 23a is set to be smaller than the inner diameter of the ironing portion (for example, 3g; see FIG. 7) of the die 3 by 2 ts (ts is the protruding height of the outer convex portion 121b1; see FIG. 20). An axis between the flat portion 3a of the die 3 and the ironing portion 23a of the ironing die 23 (when the ironing portion is formed of a circumferential line) or at the rear end (when the ironing portion is formed of a short cylindrical surface as shown in, for example, 3g in FIG. 7). The directional distance is equal to the length between the upper end 120b5 of the outer convex portion 120b1 of the opening end 120b and the lower end 120b6 of the inclined portion 120b3 (referred to as the length of the opening end in this specification). Until the punch 1 of the tool 22 is advanced and the tapered portion 1b1 of the punch 1 reaches the ironing portion of the die 3, the side wall portion 5b of the drawing cup 5 is thickened by ts by the front portion 1a of the punch 1 and the die 3.
+ Tw (FIG. 20), thinning and redrawing—ironing is performed, and ironing is performed by the die 23 so as to obtain the body main portion 120a having a predetermined thickness tw (FIG. 20). The tapered portion 1b1 of the punch 1 After the iron reaches the ironing portion of the die 3, the side wall portion 5b of the drawing cup 5 is thinned and re-drawn and ironed mainly by the reduced diameter portion 1b of the punch 1 and the die 3 until the thickness becomes tf (FIG. 20). (The ironing rate is at least 5%, preferably 10 to 40%.) Until the flange portion 120c (corresponding to the flange portion 5c) reaches the flat portion 3a of the die 3 by the die 23 (FIG. 18).
Ironing is performed at an ironing rate of, for example, 0.5 to 20% so that a trunk main portion 120a having a predetermined thickness tw (FIG. 20) is obtained. The temperature of the punch 1, the wrinkle holder 2, the dies 3, 23, and the annular bending member 6 is controlled as described in paragraph number 0031.

Next, from the redraw cup 5 to the seamless can 20
A description will be given of a specific example of fabricating. Thickness 0.19mm,
Temper T-4 (Rockwell 30T hardness: 58-64)
0.020 mm thick biaxially stretched ethylene terephthalate / ethylene isophthalate copolymer (molar ratio: 88)
/ 12, melting point 230 ° C, glass transition temperature Tg: 70 ° C)
About 50 mg / m 2 of paraffin wax (melting point Tm: 60 ° C.) on both sides of a laminated steel sheet (total thickness: 0.230 mm) produced by heat bonding the film 12.
² was applied. This laminated steel plate is punched into a circular blank 10 having a diameter of 165 mm by a draw forming machine (not shown), and the blank 10 is formed using a normal die having a processing corner with a radius of curvature Rd of 1.5 mm at a drawing ratio of 1.65. Average height is 45m by drawing
m, front drawing cup 13 having an inner diameter of 100 mm (Fig. 1)
Was prepared. The front drawing cup 13 is subjected to thinning and redrawing only by bending and stretching at a drawing ratio of 1.23 using a die having a radius of curvature Rd of a processing corner of 0.34 mm (Rd / t0 = 1.47). 72mm in diameter, 81.3m inside diameter
m, average side wall thickness 0.2 mm, (average thinning rate: 1
3%).

The re-draw cup 5 is connected to each of FIGS.
o. 1 to Test No. 7, test no. 9, Test No. 1
2, Test No. 13), an apparatus of the type shown in FIG. 4 (Test No. 8) and an apparatus of the type shown in FIG. 11 (Test No. 14, Test No. 15). 5 and test no. Except for No. 6, the surface temperature Tp of the punch 1 immediately after withdrawal was set to 60 ° C. (15 ° C. for Test No. 5, 150 ° C. for Test No. 6), and the radius of curvature R of the processing corner 3 b of the die 3.
d, the approach angle α, the gap width of the gap 15 between the punch 1 and the ironing portion 3g, and the surface temperature Td of the die 3 were changed to perform redrawing and ironing (Test Nos. 1 to 9 and Test Nos.
14, test no. 15). Note that the test No. 1 to test N
o. 6 and test no. 9, Test No. 12. Test N
o. As the die 3 in the case of 13, the one having Ri / t0 of 0.2 was used. Test No. The die 3 in the case of 7 is Ri /
Those having t0 of 10 were used. Test No. 14 and test no. The dies 3 used in the case of No. 15 had an approach angle γ of the front approach surface 3c2 of 2 degrees and 8 degrees, respectively. Test No. 16 is performed using the two-stage dice device shown in FIGS. 17 and 18. The front die 23 is of the type shown in FIG.
As the rear die 3, an ironing part (3 g) having an inner diameter of 66.292 mm was used as the rear die 3. For comparison, the redraw cup 5 was thinned and redrawn using the apparatus shown in FIG.
Test No. 11: Tp is 60 ° C). For comparison, the squeezing cup 5 is thinned and re-drawn and ironed by the two-stroke method described in paragraph No. 0041 to form a seamless can 2.
0 (Test No. 12, Test No. 13). Also, the iris cup 5 is prepared by the method described in paragraph number 0042,
The seamless can 20 was produced by thinning and redrawing and ironing (Test No. 16: Tp: 60 ° C., Ri / t0: 0.2). Test No. In the case of No. 16, the protrusion height Ts (FIG. 20) of the outer protrusion was 0.009 mm, and the protrusion height of the inner protrusion was 0.010 mm. The diameter of the front part 1a is 66 m
m and the diameter of the reduced diameter portion 1b are the same as those of Test No. 1 to Test No. 9
And Test No. 12 to Test No. 65.9 at 15
Test No. 62 mm At the time of 16, the punch 1 of 65.980 mm was used, and the drawing ratio was 1.24 in each case.

Table 1 shows the processing conditions. Table 2 shows the processing results. In Table 1, the gap widths Tf and Tw indicate the gap width between the punch and the ironing portion when forming the opening end portion 20b and the trunk main portion 20a, respectively, and the thinning rates Tf and Tw respectively indicate the opening width. It refers to the rate of thinning of the end portion 20b and the trunk main portion 20a (see FIG. 20). Note that the thinning rate of the drawing and the ironing is an abbreviation of the thinning increment rate. Test No. In the case of No. 4, the thinning rate in the drawing process is -3%, which indicates that the thickness of the side wall portion 5b has increased by 3%. In Table 2, “good appearance” refers to a state in which the outer surface side organic coating 12 is smoothed by ironing and has excellent printability.

[0047]

[Table 1]

[0048]

[Table 2]

As shown in Tables 1 and 2, Test No. 3 in which the molding conditions satisfy Claims 2 , 5, and 9 In the case of 1,
A seamless can 20 and a container 21 having a height of 130 mm and an inner diameter of 66 mm and satisfying the target dimensions were obtained. The relationship between the wall thickness of the body portion of the seamless can 20 and the position from the bottom of the can obtained in this case is shown in FIG. This is indicated by the curve 1. From about 20mm to 90mm in height from the can bottom,
It can be seen that the wall thickness is constant. Approximately 10 from the bottom of the can
The portion that is slightly thicker from 0 mm to 120 mm is the portion corresponding to the reduced diameter portion 1 b of the punch 1,
That is, this is because the opening end portion 20b. It is preferable that the thickness in the vicinity of the opening end be slightly thick because cracks hardly occur during neck-in processing or flange processing.

Test No. 3 in which the surface temperature Td of the die 3 is equal to or higher than the upper limit temperature according to claim 2 . In the case of No. 2, there was no abnormality in the moldability, but the outer surface organic coating 12 was scraped off and a satisfactory seamless can 20 could not be obtained. Claim the approach angle α
Beyond the upper limit of 9, the test does not meet the claim 9 No. 3
In the case of the above, the seamless can 20 could not be produced by breaking the cylinder. Test No. 1 in which Rd / t0 far exceeds the upper limit of claim 5 . Also in the case of No. 4, since the thickness is not reduced at the processing corner 3b, and the thickness is slightly increased after the re-drawing, the thickness of the side wall portion 5b is much larger than the gap width 15 and is large for ironing. It is thought that it took some force, but it was not possible to produce the seamless can 20 by breaking the cylinder.

Test No. 1 in which Tp of punch 1 is lower than the lower limit of claim 2 . In the case of 5, the can was formed but the punch 1
Could not be extracted from the seamless can 20, and the subsequent molding operation could not be performed. Test No. 1 in which Tp of punch 1 is higher than the upper limit of claim 2 . In the case of No. 6, the inner organic coating 12 was scraped off and a satisfactory seamless can 20 could not be produced. Test No. 5 in which the molding conditions satisfy claims 5 , 6, and 11 . In the case of Test No. 7, As in the case of No. 1, satisfactory seamless cans 20 and containers 21 were obtained. The molding conditions satisfy claim 5 , and the test No. 1 produced by the method according to claim 1. In the case of Test No. 8 as well, 1
Seamless can 20 and container 21 as satisfactory as in
was gotten. Rd slightly exceeds the upper limit of claim 5 , the approach angle α far exceeds the upper limit of claim 9 , the gap width is slightly smaller than the average thickness of the side wall 5b, and the ironing rate is extremely small. In the case of No. 9, the side wall 5b is not sufficiently thinned, a predetermined can height cannot be obtained, and the outer surface organic coating 12
However, the organic coating film 12 at the neck-in portion was whitened, and the appearance was poor, so that satisfactory seamless cans 20 and containers 21 could not be produced.

Test No. 1, which is a conventional thinning re-squeezing method that does not perform ironing only by re-drawing. In the case of 10, Rd / t0 is almost at the lower limit of claim 5 ,
The wall thickness of the side wall 5b was insufficient, and a predetermined can height could not be obtained. In addition, the test No. of FIG. As shown by the curve 10, the thickness variation in the height direction is extremely large. Furthermore, the organic coating film 12 at the neck-in portion was whitened and the appearance was poor, so that satisfactory seamless cans 20 and containers 21 could not be produced. Test No. Test No. 10 is a conventional method similar to that of Test No. 10. In the case of 11, Rd / t0 is smaller than the lower limit of claim 5 . As a result, the cylinder was broken and the seamless can 20 could not be manufactured.

Except that the redrawing step and the ironing step are separate and two-stroke machining, the test conditions are the same as those of test No. Test No. 1 which is the same as In the case of 12, satisfactory seamless cans 20 and containers 21 were obtained. The test condition was the same as that of test No. 2 except that the approach angle α far exceeded the upper limit of the ninth aspect . Test No. 12 which is the same as In the case of No. 13, there was no abnormality in the moldability, but the outer surface organic coating 12 was shaved and a satisfactory seamless can 2
0 was not obtained.

[0054] test molding conditions are satisfied the claim 2,6,10 No. In the case of No. 14, test No. As in the case of No. 1, satisfactory seamless cans 20 and containers 21 were obtained. Except for the point that the approach angle γ of the front approach surface 3c2 is larger than the upper limit of claim 10 , the test No. Test No. 14 under the same test conditions as Test No. 14 In the case of No. 15, there was no abnormality in the moldability, but the outer surface organic coating 12 was shaved and a satisfactory seamless can 20 could not be obtained.

Next, a specific example of manufacturing the seamless can 20 directly from the front drawing cup 13 (see FIG. 1) will be described. Thickness 0.19mm, Temper T-4 (Rockwell 3
A biaxially stretched ethylene terephthalate / ethylene isophthalate copolymer having a thickness of 0.020 mm (molar ratio: 88/12, melting point 230 ° C.) on both sides of tin-free steel (electrolytic chromic acid-treated steel sheet) having a 0T hardness of 58 to 64). , Glass transition temperature Tg: 70 ° C.) A laminated steel sheet (total thickness: 0.230) produced by thermally bonding the film 12
mm) with paraffin wax (melting point Tm: 60 ° C.)
After applying about 50 mg / m ² on both sides, the sheet was punched into a circular blank 10 having a diameter of 165 mm by a drawing machine (not shown).

The blank 10 is formed into a radius of curvature Rd of a processing corner.
Using a normal die having a diameter of 1.5 mm and a drawing ratio of 1.70
The average height is 46.5mm by drawing in
A front drawing cup 13 having an inner diameter of 97 mm and an average wall thickness of 0.250 mm (average thinning rate of -8%) at the side wall was produced. Using the apparatus of the type shown in FIGS. 3 and 7, the front drawing cup 13 is drawn at a drawing ratio of 1.47, the radius of curvature of the processing corner 3b is 0.34 mm (Rd / t0 = 1.47), and the angle α is 4
Re-drawing and ironing were performed under the conditions that the gap width on the ironing surface 3e was 0.137 mm, and the surface temperatures Td and Tp of the die 3 and the punch 1 were 30 ° C. and 60 ° C., respectively. The punch 1 described in paragraph number 0045 was used.

The thinning rate was 10% and 39% for drawing and ironing, respectively, and the final thinning rate was 40%. In this case, the test Nos. Like 1,
A satisfactory seamless can 20 and container 21 having a height of 130 mm, an inner diameter of 66 mm, and dimensions meeting the target values were obtained.
For comparison, the radius of curvature Rd of the processing corner 3b is 1.06.
mm (Rd / t0 = 4.60), surface temperature T of die 3
When redrawing and ironing were performed under the same conditions as above except for d of 130 ° C., shaping of the broken body and the outer organic coating 12 occurred, and molding was impossible.

As the metal plate 11, an aluminum alloy (A3004H19) having a thickness of 0.230 mm was used.
The radius of curvature Rd of the processing corner 3b of the die 3 is 0.397.
mm (Rd / t0 = 1.47), the gap width is 0.162 mm, the thinning rate is 5%, the ironing 2
Except for the above test No. 3%, Redrawing and ironing under the same conditions as in 1, height 130mm, inner diameter 6
Satisfactory seamless can 2 with dimensions of 6 mm and target value
0 and container 21 were obtained.

The present invention is not limited by the above-described embodiments. For example, as the organic coating, polyethylene, polypropylene, ethylene-propylene copolymer,
Olefin-based resin films such as ethylene-vinyl acetate copolymer, ethylene-acrylic ester copolymer, ionomer, or polyester film such as polybutylene terephthalate, or nylon 6, nylon 6,
6, non-stretched or biaxially stretched thermoplastic resin film such as polyamide film such as nylon 11, nylon 12, polyvinyl chloride film, polyvinylidene chloride film, etc., by heat fusion, dry lamination, extrusion coating, etc. It may be a single layer or a plurality of layers laminated on a metal plate (thickness: 3 to 50 μm). When an adhesive is used for lamination, a urethane adhesive, an epoxy adhesive, an acid-modified olefin resin adhesive, a copolyamide adhesive, a copolyester adhesive (thickness: 0.1
To 5.0 μm) is preferably used.

Further, as the organic film, modified epoxy paints such as phenol epoxy and amino-epoxy, vinyl chloride-vinyl acetate copolymer, saponified vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, Epoxy-modified, Epoxyamino-modified, Epoxyphenol-modified thermoplastic or thermosetting paint such as vinyl paint or modified vinyl paint, acrylic paint, synthetic rubber paint such as styrene-butadiene copolymer, etc. Combination of the above (dry thickness: 2-3)
0 μm).

As the lubricant, there is no problem in food hygiene,
Those which can be easily volatilized and removed by heating at about 200 ° C., for example, liquid paraffin, synthetic paraffin, white petrolatum, edible oil, edible oil with water, palm oil, various natural waxes, polyethylene wax and the like are preferably used. The coating amount is preferably 0.1 to 10 mg / dm ² . Dice shape,
Although dimensions and the like are not shown in the drawings, those described in claims 9 to 14 are included.

[0062]

According to the inventions according to the first, second, third, and fourth aspects, the breaking limit of the thinning of the side wall is smaller than that of the metal cup whose inner and outer surfaces are coated with the organic film. The thickness distribution in the height direction of the side wall portion is controlled, the thickness in the circumferential direction is uniform, and at the time of post-processing such as neck-in processing,
Hardly occurs deterioration of whitening or the like of the organic film and the organic film is excellent in printability by smoothing, it can produce a relatively elongated seamless cans sidewall portion is thin, and ironing pressure
During the construction, the organic coating on the inner and outer surfaces is less likely to be scraped or broken.
Easily removes the punch from the seamless can after molding
There is an effect that is Ru can be. The invention according to claim 1 is different from the invention according to claim 2 in that there is no approach surface and it can be considered that Rd = Ri substantially, so that the contact length of the die during ironing is short, and the punch can be pulled out. It has the advantage of being easier. The invention according to claim 2 has an advantage over the invention according to claim 1 in that the processing heat generated by bending and drawing is released from the approach surface to the die side, so that an increase in the can temperature is suppressed. The invention according to claim 3 has an advantage that the punch can be more easily extracted than the invention according to claim 1 without impairing the appearance to the left. In the invention according to claim 4 , the punch is extracted without damaging the appearance to the left.
Has the advantage of being easier than the invention according to the above. The advantage relationship between the invention according to claim 3 and the invention according to claim 4 is the same as the advantage relationship between the invention according to claim 1 and the invention according to claim 2.

The invention according to claim 5 has an advantage that the thickness can be reduced by bending and stretching without causing the side wall to be broken at the stage before the ironing, so that the thickness can be easily reduced by the ironing. Have. The invention according to claim 6 is characterized in that the surface temperature of each tool is set to an appropriate temperature within a predetermined temperature range, whereby the inner and outer organic coatings are less likely to be shaved or broken during ironing, and the punch after forming is formed. Has the merit that it can be easily removed from the seamless can. The invention according to claim 9 has an advantage that the outer organic film is hardly shaved during ironing. The invention according to claim 10 has the advantages that the outer surface organic coating is less likely to be scraped during ironing, and that the punch is more easily extracted than the invention according to claim 9 .

The invention according to claim 11 is the invention according to claim 2
In the case of implementing the invention according to 4 , the outer organic coating is less likely to be shaved during ironing, and the punch must be removed.
There is a merit that it is easier to make it easier than in the case of the invention according to claim 9 . The invention according to claim 12 is:
It has the advantage that the life of the ironing part is long. The invention according to claim 13 has an advantage that the outer organic film is hardly scraped when the seamless can is extracted from the die. The invention according to claim 14 has the advantages that it is easy to pull out the seamless can from the die after molding, and the outer organic coating is hardly shaved during the pulling-out.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an example of steps from a blank until a seamless can of the present invention is manufactured, where blank is a pre-drawn cup, is a re-drawn cup, and is a seamless can.

FIG. 2 is a longitudinal sectional view of an example of a container body made from the seamless can of FIG.

FIG. 3 is a longitudinal sectional view showing a state in which the seamless can of FIG. 1 is being formed in one stroke.

FIG. 4 shows a case where the dice according to the first embodiment is used.
It is an expanded longitudinal cross-sectional view of a part.

FIG. 5 is a longitudinal sectional view showing a state immediately after the formation of the seamless can of FIG. 1 is completed.

FIG. 6 is a longitudinal sectional view of a first embodiment of a seamless can different from the seamless can of FIG. 1 manufactured by the method of the present invention.

FIG. 7A shows a case where the dice according to the second embodiment is used.
It is an expanded longitudinal cross-sectional view of a part.

FIG. 8A shows a case where the dice according to the third embodiment is used.
It is an expanded longitudinal cross-sectional view of a part.

FIG. 9 illustrates a case where the dice according to the fourth embodiment is used.
It is an expanded longitudinal cross-sectional view of a part.

FIG. 10 is an enlarged vertical sectional view of a portion A in FIG. 3 when the die of the fifth embodiment is used.

FIG. 11 is an enlarged longitudinal sectional view of a portion A in FIG. 3 when the die of the sixth embodiment is used.

FIG. 12 is a longitudinal sectional view showing a state during drawing, which is a drawing showing, for reference, a method of forming the seamless can of FIG. 1 in two strokes.

FIG. 13 is a longitudinal sectional view showing a state during ironing , which is a drawing showing, for reference, a method of forming the seamless can of FIG. 1 in two strokes.

FIG. 14 is a longitudinal sectional view showing a state in which a seamless can of a second mode different from the seamless can of FIG. 1 is being formed.

FIG. 15 is a longitudinal sectional view showing a state immediately after the formation of the seamless can of the second embodiment different from the seamless can of FIG. 1 is completed.

FIG. 16 is a longitudinal sectional view of a seamless can of a second embodiment different from the seamless can of FIG. 1;

FIG. 17 is a longitudinal sectional view showing a state where a seamless can of a third mode different from the seamless can of FIG. 1 is being formed.

FIG. 18 is a longitudinal sectional view showing a state immediately after the formation of the seamless can of the third mode different from that of FIG. 1;

FIG. 19 is a vertical sectional view of a seamless can of a third embodiment different from the seamless can of FIG.

FIG. 20 is an enlarged vertical sectional view of a portion B in FIG. 19;

FIG. 21 is a diagram showing an example of the relationship between the height from the can bottom and the thickness of the body of the seamless can manufactured by the method of the present invention and the seamless can of the comparative example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 punch 1 ′ punch 2 wrinkle holder 3 dice 3 a flat surface 3 b processing corner 3 b 1 ironing part 3 c approach surface 3 d connecting part 3 d 1 connecting part 3 d 2 connecting part 3 e flank 3 g ironing part 5 metal redraw cup b metal cup Side wall part 7 Cavity 12 Organic coating 20 Seamless can 20 'Seamless can 20 "Seamless can 23a Ironing part 120 Seamless can 120a Body main part 120b Open end

────────────────────────────────────────────────── (5) Continuation of the front page (51) Int.Cl. ⁶ Identification code FI B65D1 / 26 B65D1 / 26Z (56) References JP-A-57-149033 (JP, A) JP-A-4-118121 ( JP, A) JP-A-1-258822 (JP, A) JP-A-62-227531 (JP, A) JP-A-2-274325 (JP, A) JP-A-1-306023 (JP, A) JP Hei 6-210381 (JP, A) Tokuyo 56-501442 (JP, A) Tokuyo 4 -500175 (JP, A) Tokai Sho 56-169926 (JP, U) (58) Fields surveyed (Int) .Cl. ⁶ , DB name) B21D 22/28 B21D 51/26

Claims (14)

(57) [Claims] 1. A method for manufacturing a relatively elongated seamless can using a punch, a wrinkle presser and a die from a metal cup whose inner and outer surfaces are coated with an organic film, wherein the wrinkle presser is inserted into the metal cup. While pressing the bottom of the metal cup against the plane of the die with a wrinkle presser, advance the punch into the cavity of the die, and bring the outer surface of the side wall of the metal cup into close contact with the plane of the die and the processing corner where the radius of curvature of the die is small. Meanwhile, the thickness of the side wall portion is reduced by bending and stretching at the processing corner, and the punch and the front end of the processing corner, or the ironing portion formed of a short cylindrical portion connected to the front end, cooperate with the side wall thickness. And at least 5 on the side wall to be the open end of the seamless can
% Of ironing rate ironing row Do I of, using the metal cup
Molded into a stainless steel can, and before the above molding work, die and wrinkles
Heats the presser and the inside of the punch and heats immediately before molding starts
Switch to cooling, keep cooling during molding, and
Surface temperature T of the portion in contact with the side wall of the metal cup
d, surface temperature of the part of the wrinkle holder that faces the die plane
Temperature Ts and the punch surface temperature Tp
Glass transition temperature Tg + 50 ° C or less for machine coating and 10 ° C or less
A method for producing a seamless can, characterized in that it is maintained at an appropriate temperature within the above temperature range . 2. A method of manufacturing a relatively elongated seamless can using a punch, a wrinkle presser and a die from a metal cup whose inner and outer surfaces are coated with an organic coating, wherein the wrinkle presser is fitted into the metal cup, While pressing the bottom of the metal cup against the plane of the die with a wrinkle presser, advance the punch into the cavity of the die, and bring the outer surface of the side wall of the metal cup into close contact with the plane of the die and the processing corner where the radius of curvature of the die is small. Meanwhile, the thickness of the side wall is reduced by bending and stretching in the processing corner, and then the side wall is advanced slightly obliquely inward in the cavity, and the thickness of the side wall is reduced by cooperation between the punch and the ironing portion of the die. more reduced at least 5% of the ironing ratio ironing line Do I, seam metal cup on the side wall portion to the open end of the seamless can
Dies and wrinkle press before the above molding work
Heat the fixture and punch, and cool immediately before starting molding
To the die, keep cooling during molding,
Surface temperature Td, wrinkles at the part in contact with the side wall of the metal cup
Surface temperature T of the part of the holder that faces the die plane
s and the punch surface temperature Tp immediately after withdrawal are determined by organic coating.
The glass transition temperature Tg of the film is not higher than + 50 ° C. and not lower than 10 ° C.
A method for producing a seamless can, characterized in that each can is maintained at an appropriate temperature within a temperature range . 3. A metal cup whose inner and outer surfaces are coated with an organic film, is relatively elongated by using a punch, a wrinkle presser and a die having a front portion and a reduced diameter portion slightly smaller than the front portion behind the metal cup. A method of manufacturing a seamless can having a trunk main portion and an opening end having an inner convex portion and an outer convex portion with a slightly greater thickness than the trunk main portion, wherein a wrinkle retainer is fitted into a metal cup, While pressing the bottom of the metal cup against the plane of the die with a wrinkle presser, advance the punch into the cavity of the die, and bring the outer surface of the side wall of the metal cup into close contact with the plane of the die and the processing corner where the radius of curvature of the die is small. Meanwhile, the thickness of the side wall portion is reduced by bending and stretching at the processing corner, and further, a punch front portion, a front ironing portion of the processing corner, or a rear ironing portion comprising a short cylindrical portion connected to the front end portion, and a rear ironing portion. The thickness of the side wall portion is further reduced by cooperating with the front ironing portion having an inner diameter smaller than the rear ironing portion provided in front of the main body portion, and the reduced diameter portion of the punch and the rear ironing portion are formed. A method for producing a seamless can, characterized in that ironing is performed on a side wall portion to be an opening end by an ironing rate of at least 5% in cooperation to form an opening end. 4. A metal cup whose inner and outer surfaces are coated with an organic film, which is relatively elongated by using a punch, a wrinkle presser and a die having a front portion and a reduced diameter portion slightly smaller than the front portion behind the metal cup. A method of manufacturing a seamless can having a trunk main portion and an opening end having an inner convex portion and an outer convex portion with a slightly greater thickness than the trunk main portion, wherein a wrinkle retainer is fitted into a metal cup, While pressing the bottom of the metal cup against the plane of the die with a wrinkle presser, advance the punch into the cavity of the die, and bring the outer surface of the side wall of the metal cup into close contact with the plane of the die and the processing corner where the radius of curvature of the die is small. Meanwhile, the thickness of the side wall is reduced by bending and stretching at the processing corner, and then the side wall is advanced slightly obliquely inward in the cavity to make contact with the rear ironing part , and the punch front part, the rear ironing part and the like. The thickness of the side wall portion is further reduced by cooperation with the front ironing portion having an inner diameter smaller than that of the rear ironing portion provided in front of the rear ironing portion, thereby forming a trunk main portion, and the reduced diameter portion of the punch and the rear portion. A method for producing a seamless can, characterized in that an opening end is formed by performing ironing at least 5% on a side wall portion to be an opening end in cooperation with an ironing portion. 5. The ratio Rd / t0 of the radius of curvature Rd of the processing corner to the blank thickness t0 of the metal cup is 1.0 to 1.0.
The method for producing a seamless can according to claim 1, 2, 3, or 4, which is 2.9. 6. The inside of the die, the wrinkle presser and the punch are heated before the molding operation, the heating is switched to cooling immediately before the start of the molding, and the cooling is continued during the molding. The surface temperature Td of the part in contact with the part, the surface temperature Ts of the part facing the die plane part of the wrinkle suppressor, and the punch surface temperature Tp immediately after the extraction are 10 ° C. or more at the glass transition temperature Tg + 50 ° C. or less of the organic film. The method for producing a seamless can according to claim 3 or 4, wherein the temperature is maintained at an appropriate temperature within the above temperature range. 7. A flow through a die, a wrinkle retainer and a punch.
Drill, wrinkle retainer and punch before forming
Hot water flows into the inside and switches hot water to cold water just before molding starts
In addition, cold water is poured into the dies, wrinkle retainers and punches during molding.
The method for producing a seamless can according to claim 1, 2 or 6 , wherein the seamless can continues to flow . 8. The method according to claim 1, wherein the organic film is a linear polyester-based film.
The method for producing a seamless can according to claim 1, 2, 3, 4, 5, or 6, wherein 9. An approach angle α, which forms an axis of the die, of an approach surface extending slightly obliquely inward to an ironed portion of the die, is 1 to 5 degrees, and the approach surface and the ironed portion are:
Sharp corners or 0.3xt0 smaller curvature claim are connected via a curved portion having a radius Ri 2 or 4,
A method for producing the seamless can as described above. 10. An approach surface extending slightly obliquely inward to an ironing portion of the die comprises a rear approach surface and a front approach surface, and the approach angle α between the rear approach surface and the axis of the die is 1 to 15. And the approach angle γ that forms the axis of the die on the front approach surface is 1 to
5 degrees, and the approach angle α is larger than the approach angle γ, and the rear approach surface, the front approach surface, and the front approach surface and the squeezed portion have a sharp corner or a radius of curvature Ri smaller than 0.3 × t0. The method for producing a seamless can according to claim 2 or 4 , wherein the seamless cans are connected via a. 11. The approach angle α, which forms the axis of the die, of the approach surface extending slightly obliquely inward to the ironed portion of the die is 1 to 45 degrees, and the approach surface and the ironed portion are (0.3). 20) The method for producing a seamless can according to claim 2 or 4 , wherein the seamless cans are connected via a curvature portion having a curvature radius Ri of xt0. 12. seamless can manufacturing method of the ironing portion of the die according to claim 2 or 4, wherein the short cylindrical. 13. seamless can manufacturing method of the die ironing unit according to claim 2 or 4 consisting of the circumferential line. 14. A flank extending in front of the ironing portion and extending slightly obliquely outward and having a clearance angle β with the axis of the cavity of 5 degrees or less is provided. A method for producing the seamless can as described above.