JP2007084098A - Forming and working method of aluminum can - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a cost by making a variation in height of a DI can after DI working in the circumference and by decreasing cut pieces during trimming. <P>SOLUTION: An optimum shape is given to a blank material to be subjected to DI working. Concretely radial length of the blank material in a direction of 0 degree and in a direction of 60 degrees to a rolling direction of an aluminum rolled plate for a can raw material are relatively 0.7 to 1.6% and 0.8 to 1.8% shorter than the radial length in a direction of 90 degrees respectively. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an aluminum can used as a beverage container for beer, tea, soft drinks, etc., in particular, a DI can produced by subjecting a rolled aluminum plate to a blank material obtained by punching and punching a blank. The present invention relates to a method for forming a can body.

  The can body of a beverage aluminum can is generally formed by the following process. First, a rolled aluminum plate is used as a can material, and this is first punched into a circular shape as shown in FIG. 3A to produce a circular blank material (11) having a predetermined size. Next, the blank material (11) is drawn to form a cup material (12) having a short bottom cylindrical shape as shown in FIG. 3 (B), and further redrawing and ironing. (Ironing) is performed to form a DI can (13) corresponding to the can body shape as shown in FIG. Then, a can having a predetermined can height and diameter can be obtained by performing a trimming process by cutting and removing the wavy tip portion of the upper edge (14) on the can mouth side of the DI can (13) with a horizontal trimming line (T). After forming the body molded body, the diameter of the can mouth portion is slightly reduced by necking, and then a flange for tightening and attaching the can lid is formed by flange processing. The can body completed in this way is filled with a predetermined beverage, sealed with a can lid wrapped around a can mouth, and supplied as a beverage can.

  In this specification, the term “DI processing” is used to mean a series of processing steps including drawing, redrawing, and one or more stages of ironing. Therefore, the term “DI can” is used to mean a molded can obtained through DI processing.

  By the way, in the conventional can processing of the can body of the above aluminum can, when blank material is punched from the aluminum rolled plate used as the can material, it is punched into a perfect round shape, and the round shape obtained thereby It was common to use a blank as a starting material for processing.

  However, in the DI can molded from such a round blank, in the can shape at the stage before trimming after the DI processing, the upper edge (14) on the can mouth side has a considerably large wavy deformation. Have That is, in the circumferential direction of the can, there is a very large variation in the can height (difference between the maximum height and the minimum height). In particular, in the manufacture of aluminum cans, which are generally called long cans whose height of the can body exceeds 160 mm, and where severe drawing and ironing is applied during the DI processing stage, the above-mentioned variation is prominent.

  The cause of the variation in the can height is mainly due to the rolling anisotropy imparted at the production stage of the can material by the aluminum rolled sheet. That is, the aluminum rolled sheet has different elongation characteristics specific to the material depending on the rolling direction. For this reason, as shown schematically in FIG. 3 (C) and FIG. 4 (A), a DI can that has been DI processed starting from a true circular blank has a different can height depending on the rolling direction of the can material. It will be a thing. Specifically, as shown in FIG. 4 (A), a mountain-shaped ear (13a) having a high height is generated in a region portion of 0 ° azimuth and 45 ° azimuth with respect to the rolling direction, and between them, Mainly, the region of 90 ° azimuth becomes a deep valley (13b).

  When such cans after DI processing having different heights in the circumferential direction are subjected to trimming and then the can heights are trimmed, there is a processing margin below the valley (13b). The can body is cut at a horizontal trimming line (T) in which a slight trim margin (f) is set. For this reason, as shown in FIG. 4 (13), the trimming removal piece (13c) occupies a considerably large cut area in the ear (13a) region, resulting in a large material loss.

  In the production of aluminum cans, reducing the production cost is an extremely important issue due to the huge amount consumed. For this purpose, cost reductions such as improving the yield rate by reducing can cracks that occur during DI processing, including reducing the thickness of the can as much as possible while maintaining the required strength. Various improvement measures for this purpose have been studied. Under such a background, the trimming removal piece (13c) has a relatively large area due to the presence of the mountain-like high ear (13a) as described above, and the loss resulting from the material loss is a cost reduction. It is clear that this is a huge obstacle.

  Conventionally, various improvement measures have been tried in the direction of reducing the anisotropy of the aluminum rolled sheet of the can material with respect to the problem of the material loss derived from the size of the trimming removal piece as described above. As a result, some results have been achieved, but as long as the can material is manufactured by rolling, rolling anisotropy is a problem that inevitably occurs, and the above problems have been accepted as inevitable. Is the actual situation.

  On the other hand, the following Patent Document 1 can be seen as a related art that is somewhat related to the problem of ears occurring on the rim side of the DI can.

  In Patent Document 1, after trimming a DI molded can and making the height of the upper edge uniform in the circumferential direction, the can mouth is newly drawn at the can mouth edge by drawing, that is, necking. Focus on the ear problem. That is, the overhang width of the flange for tightening the can lid formed by the subsequent flange processing due to the variation in the height of the can after the necking caused by the necking process for reducing the diameter of the can after the trimming process It will be noted that there is a possibility that the sealing in the can lid may be hindered as a result of the occurrence of variations in the circumferential direction.

And, as a measure for solving this problem, based on the knowledge that the anisotropy of the aluminum rolled sheet of the can material is related, the blank material is in the radial direction of 0 ° and 45 ° with respect to the can material rolling direction. This is a technique which proposes a technique of punching in a substantially circular shape in which the length is shorter than the length in the radial direction in the 90 ° direction by a predetermined range.
Japanese Patent Laid-Open No. 11-169979

  However, the technology according to this prior proposal relates to the ear problem caused by the necking process, and teaches any solution for the problem of the larger can height variation caused by the DI process. Of course, even if this prior proposal technique is adopted in the blank punching process, the above problem cannot be solved.

  Under the background of the prior art as described above, the present invention greatly reduces the degree of large variation in the can height in the circumferential direction of the DI can after DI processing, and as a result, the removed piece removed by trimming processing. An object of the present invention is to provide a molding method that can reduce the volume and weight of the aluminum can and contribute to the cost reduction of the aluminum can, particularly a molding method of the aluminum can body.

  The present invention provides the following means for solving the above problems.

[1] In a forming method of an aluminum can obtained by punching a blank from a can material made of a rolled aluminum plate, forming a cup material from the blank, and obtaining a DI formed can by DI processing.
A step of punching the blank material into a non-circular substantially circular shape,
The non-circular substantially circular blank has a radial length of 0 ° azimuth with respect to the rolling direction of the can material, and a range of 0.7 to 1.6% with respect to a radial length of 90 ° azimuth. A method for forming an aluminum can, characterized in that the length is set short.

[2] In an aluminum can molding method for punching a blank material from a can material made of a rolled aluminum plate, forming a cup material from the blank material, and obtaining a DI molded can by DI processing,
A step of punching the blank material into a non-circular substantially circular shape,
The non-circular substantially circular blank has a length in the radial direction of 60 ° with respect to the rolling direction of the can material, and a range of 0.8 to 1.8% with respect to a length in the radial direction of 90 °. A method for forming an aluminum can, characterized in that the length is set short.

[3] In an aluminum can molding method of punching a blank material from a can material made of a rolled aluminum plate, forming a cup material from the blank material, and obtaining a DI molded can by DI processing,
A step of punching the blank material into a non-circular substantially circular shape,
The non-circular substantially circular blank has a radial length of 0 ° azimuth with respect to the rolling direction of the can material, and a range of 0.7 to 1.6% with respect to a radial length of 90 ° azimuth. And forming a 60 ° azimuth radial direction short in the range of 0.8 to 1.8%.

  [4] Any of [1] to [3] above, wherein the variation in the height of the DI can after DI processing (difference between the maximum height and the minimum height in the circumferential direction) is controlled to 1.5 mm or less. A method for forming an aluminum can according to claim 1.

  [5] The method for forming an aluminum can according to any one of [1] to [4], wherein the can material is a JIS 3000 series aluminum alloy rolled plate.

  [6] An aluminum can manufactured by the molding method according to any one of [1] to [5].

  According to the method for forming an aluminum can according to the invention [1], a radial direction of 0 ° azimuth with respect to the rolling direction of the can raw material aluminum rolled plate tends to generate the highest mountain-like ear by DI processing. DI processing including cupping using a non-circular substantially circular blank whose length is set short in the range of 0.7 to 1.6% with respect to the radial length of 90 ° azimuth. As a result, the height level of the maximum can height region in the case of a DI can that has been DI processed using a conventional round blank can be sufficiently reduced. This makes it possible to greatly reduce the degree of variation in can height in the circumferential direction as compared to conventional DI cans. As a result, it becomes possible to set the apparent height of the trimming removal portion to be cut and removed in the trimming processing after DI processing, and to improve the production yield of aluminum cans and reduce costs by reducing material loss. Can do.

  According to the method for forming an aluminum can according to the invention [2], a 60 ° azimuth that produces an ear having a height next to the maximum height ear generated in the portion of the 0 ° azimuth by DI processing, and sometimes an ear having a height higher than that. A non-circular substantially circular blank having a radial length set to be shorter in a range of 0.8 to 1.8% with respect to a radial length of 90 ° azimuth is used for DI including cupping. By using it for processing, variation in the circumferential height of the DI can can be kept low as described above, which can contribute to reduction of material loss, improvement of yield, and cost reduction.

  In the molding method of the invention [3], the variation in the circumferential height of the DI can can be controlled to be even smaller by the combination of the inventions [1] and [2]. 1] The effects of [2] can be enjoyed synergistically, and can often contribute to cost reduction and yield improvement.

  In the method of forming an aluminum can of the invention [4], the variation in the height of the can of the DI can is controlled to 1.5 mm or less by applying any one of the methods of the inventions [1] to [3]. Therefore, the above-mentioned effect due to the reduction of material loss can be surely enjoyed.

  According to the method for forming an aluminum can according to the invention [5], by using a JIS 3000 series aluminum alloy rolled plate having a good balance between formability and strength required as a can material, An aluminum can excellent in quality can be produced while reliably achieving the effects [1] to [4].

  The aluminum can according to the invention [6] can be manufactured and provided at a low price for aluminum cans for beverages and the like that are consumed in large quantities.

  Next, embodiments of the present invention will be described more specifically.

  The forming method for producing an aluminum can according to the present invention follows the same steps as the conventional steps in the basic steps. That is, in the same manner as in the conventional forming method, after using a can material made of an aluminum rolled plate, a blank material is punched out from the can material, and then the blank material is drawn to form a cup material. A molded can is obtained. Then, the tip portion of the DI can on the can mouth side is cut and removed by a horizontal trimming surface to obtain a can body molded body having a uniform can height in the circumferential direction.

  In the above can manufacturing method, the present invention, when punching a blank material from a rolled aluminum plate can material, rather than punching it into a perfect circle as in the prior art, punching into a non-circular substantially circular shape, A substantially circular blank material having a specific shape is obtained, and this is characterized in that it is subjected to subsequent molding processes.

FIG. 1 shows the shape of a blank material before punching from a rolled aluminum sheet. A region indicated by a dotted line in FIG. 1 shows the outer shape of a conventional general blank material having a diameter of, for example, 158 mm. In contrast to the conventional perfect circular blank material (10), the blank material (1) according to the present invention has a non-circular substantially circular shape shown by a solid line in FIG. Specifically, with respect to the rolling direction of the rolled aluminum plate of the can material indicated by the arrow (2) in FIG. 1, the two points of the outer peripheral edge of the 0 ° orientation of the blank (1) and a _1, a _2, When four points of 60 ° azimuth are b ₁ , b ₂ , b ₃ , and b ₄ and two points of 90 ° azimuth are c ₁ and c ₂ , the radial length (L ₀ ) (L ₆₀ ) ( _L90 ) is set to a relatively specific dimension range.

With respect to the rolling direction (2), the radial length (L ₀ ) of ₀ ° azimuth is the distance between points a _{1 and} a ₂ , and the radial length of 60 ° azimuth (L ₆₀ ) is , Points b ₁ -b ₄ , and points b ₂ -b ₃ , and the radial length (L ₉₀ ) of 90 ° azimuth is the distance between points c ₁ -c ₂ .

And Thus, in the present invention, the 0 ° radial length of the orientation of the blank (1) (L ₀₎ is 0 in this respect to the radial direction of the length of the 90 ° azimuth (L _90). It is set relatively short in the range of 7 to 1.6%. Further, the radial length (L ₆₀ ) of the ₆₀ ° azimuth is relatively in the range of 0.8 to 1.8% of the radial length (L ₉₀ ) of the 90 ° azimuth. It is set short. That is, the length (L ₀ ) in the ₀ ° azimuth is 98.4 to 99.3% of the length (L ₉₀ ) in the ₉₀ ° azimuth, and the length (L ₆₀ ) in the 60 ° azimuth. Is set to a length of 98.2 to 99.2% of the length of the 90 ° azimuth (L ₉₀ ). Specifically, for example, when the length (L ₉₀ ) is set to 158 mm, the length (L ₀ ) is in the range of about 155.5 to 156.9 mm, and the length (L ₆₀ ) is about It means that it is set in the range of 155.2 to about 156.7 mm.

The most preferred range of the radial length of the 0 ° azimuth (L ₀₎ is from 0.9 to 1.5% short range with respect to the length of the 90 ° azimuth (L _90), the 60 ° orientation The most preferable range of the length (L ₆₀ ) in the radial direction is 1.0 to 1.3% shorter than the length (L ₉₀ ) in the 90 ° azimuth.

The length (L ₀ ) (L ₆₀ ) (L ₉₀ ) of each radial direction in the 0 ° azimuth, 60 ° azimuth, and 90 ° azimuth with respect to the rolling direction of the blank material (1) is in the range of relative values as described above. When the blank material (1) is drawn into a cup material and subsequently subjected to redrawing and ironing to form a DI can for a 500 ml can having a can body height of 168 mm, for example, As shown in FIG. 2A, the phase difference between the peaks (4a) and valleys (4b) generated at the upper edge (4) on the can mouth side of the DI can (3) is extremely small. That is, the variation in the can height in the circumferential direction of the DI can (3) can be suppressed to 1.5 mm or less. This variation can be controlled to a smaller value by the optimum design of the relative value of each of the lengths (L ₀ ), (L ₆₀ ), and (L ₉₀ ), and preferably as shown in the examples described later. In addition, it is preferable to control the thickness of the DI can (3) to be less than 1.0 mm in this way. As shown in FIG. 2 (B), the trimming removal piece (3c) can be made to have a small apparent height, and the material loss due to the removal piece (3c) is reduced, so that the material for can manufacturing Yield can be improved.

In addition, the blank material (1) according to the application of the present invention can optimize the blank shape by determining the radial lengths (L ₀ ), (L ₆₀ ), and (L ₉₀ ) of each of the three orientations. Therefore, there is an advantage that the punching punch for punching the blank material (1) can be designed and manufactured easily.

In addition, the outer periphery between the points a ₁ , a ₂ , b _{1 to} b ₄ , c ₁ , c ₂ adjacent to the outer periphery of the blank material (1) in each of the above directions is shown in FIG. It is preferable to have a shape connected by smooth arc-like lines in order to keep the variation in can height within a predetermined small value range.

  In addition, the aluminum material of the can material used for the forming process of the aluminum can according to the present invention has been widely used conventionally so that the forming process can be smoothly performed while maintaining or guaranteeing the required characteristics of the can. It is preferable to use a JIS 3000 series aluminum alloy, specifically, an Al-Mn alloy such as JIS 3003, 3004, 3104.

  The examples shown here, including the conventional example and the comparative example, are intended for the production of a 500 ml aluminum can having a can body diameter of about 66 mm and a can body height of about 168 mm.

  As a can material, an aluminum rolled plate made of JIS3004-H19 material and having a base plate thickness of 0.285 mm was used.

  First, blank materials of various shapes shown in Table 1 were produced from this can material by punching. While the diameter of the perfect circular blank material (conventional example of sample 1) is set to 158 mm, the non-circular substantially circular blank material (examples and comparative examples of samples 2 to 9) has a 90 ° azimuth perpendicular to the rolling direction. Similarly, the length in the radial direction was set to 158 mm.

  First, a cup material having a height of 37 mm was prepared using a punch having a diameter of 97 mm using the various blank materials described above.

  Next, in accordance with the conventional DI process, the cup material is further subjected to one redrawing process and three ironing processes in succession, so that the can for the 500 ml can can be obtained. A DI can serving as a body portion was produced.

  And about these various DI cans obtained, the variation in the can height in the circumferential direction (difference between the maximum height and the minimum height) was measured. The results are shown in Table 1.

  As shown in Table 1 above, sample Nos. Using conventional round blanks were used. In the conventional example of 1, the can height variation of the DI can was large exceeding 2.3 mm. On the other hand, sample No. which is an embodiment of the present invention is used. In 3 to 6 DI cans, the variation in the height of the cans was in the range of about 0.6 to 0.9 mm. In addition, sample No. In the 7 and 8 DI cans, the variation in the can height was within the range of about 1.4 to 1.5 mm. On the other hand, in the DI can of the comparative example (sample Nos. 2 and 9) manufactured under the condition that the shape of the blank material deviates from the specified range of the present invention, the variation in the can height is 2. A large value exceeding 0 mm was exhibited.

  From the above test results, it was confirmed that the DI can produced by the molding method according to the present invention can make the size of the excised piece relatively small in the trimming performed thereafter. . By the way, from this result, when the improvement rate of the material yield of the can raw material aluminum rolled sheet was calculated, it was found that the material yield per can can be improved by about 0.5% to about 1.5% compared to the conventional case. .

It is explanatory drawing which exaggerated a little and showed the characteristic of the shape of the blank material by the shaping | molding processing method of this invention for easy understanding. The shape of the DI can obtained by the shaping | molding processing method of this invention is shown, (A) is the whole perspective view of DI can, (b) is a perspective view of the can mouth part which shows a trimming process state. The usual process of DI shaping | molding process is shown in order of a process, (A) is a perspective view of a blank material, (B) is a perspective view of a cup material, (C) is a schematic longitudinal cross-sectional view of DI can after DI shaping | molding. . The shape of a DI can obtained by a DI forming method starting from a conventional round blank material is shown. (A) is an overall perspective view of the DI can, and (B) is a perspective view of the can mouth portion showing a trimming state. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Blank material 2 ... Rolling direction 3 ... DI can 3a ... Trimming cut piece 4 ... Upper edge 4a ... Mountain 4b ... Valley L ₀ ... 0 with respect to rolling direction Radial length of ° orientation L _60: Radial length of 60 ° orientation relative to rolling direction L _90: Radial length of 90 ° orientation relative to rolling direction

Claims (6)

In the aluminum can molding method of punching a blank from a can material made of a rolled aluminum plate, molding a cup from the blank, and obtaining a DI molded can by DI processing,
A step of punching the blank material into a non-circular substantially circular shape,
The non-circular substantially circular blank has a length in the radial direction of 0 ° with respect to the rolling direction of the can material and a range of 0.7 to 1.6% with respect to a length in the radial direction of 90 °. A method for forming an aluminum can, characterized in that the length is set short. In the aluminum can molding method of punching a blank from a can material made of a rolled aluminum plate, molding a cup from the blank, and obtaining a DI molded can by DI processing,
A step of punching the blank material into a non-circular substantially circular shape,
The non-circular substantially circular blank has a length in the radial direction of 60 ° with respect to the rolling direction of the can material, and a range of 0.8 to 1.8% with respect to a length in the radial direction of 90 °. A method for forming an aluminum can, characterized in that the length is set short. In the aluminum can molding method of punching a blank from a can material made of a rolled aluminum plate, molding a cup from the blank, and obtaining a DI molded can by DI processing,
A step of punching the blank material into a non-circular substantially circular shape,
The non-circular substantially circular blank has a radial length of 0 ° azimuth with respect to the rolling direction of the can material, and a range of 0.7 to 1.6% with respect to a radial length of 90 ° azimuth. And forming a 60 ° azimuth radial direction short in the range of 0.8 to 1.6%.   The aluminum according to any one of claims 1 to 3, wherein variation in the height of the DI can after DI processing (difference between the maximum height and the minimum height in the circumferential direction) is controlled to 1.5 mm or less. Molding method for cans.   The method for forming an aluminum can according to any one of claims 1 to 4, wherein the can material is a rolled JIS 3000 series aluminum alloy sheet. The aluminum can manufactured by the shaping | molding method of any one of the said Claims 1-5.

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