Method for manufacturing laminatable container

Abstract

To provide a method for efficiently manufacturing a laminatable bottomed cylindrical container made of aluminum or an aluminum alloy and used as a drinking or eating utensil, etc.SOLUTION: This method includes: executing a redrawing process for an object part 20a to be redrawn which is a part from a lower end to a prescribed height of 2 / 5 or less of a height of a machined container of a bottomed cylindrical body 20 without using a wrinkle pressing fixture; and executing a diameter expansion process for an object part 60 to be diameter-expanded which is a part from all parts excluding the object part 20a or an upper end to a position of a fixed height above the object part 20a of the bottomed cylindrical body 20. The diameter expansion process forms at least a predetermined range part of the object part 60 to be diameter-expanded in a height direction into a tapered shape reduced in inner and outer diameters toward a lower side.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a method for producing a cylindrical, stackable container with a bottom made of aluminum or an aluminum alloy, which can be used as drinking tableware or the like. [Background technology]

[0002] Approximately 3 billion bottle-shaped aluminum cans are produced annually around the world as beverage containers. The seamless can body is made from aluminum sheet material through deep drawing and ironing processes, and the open end is then subjected to a diameter reduction and folding (curling) process to form a drinking spout.

[0003] Compared to so-called two-piece aluminum cans, in which the lid, which is slightly smaller than the body, is double-seamed to the body, bottle-shaped aluminum cans have a larger reduction in diameter at the opening. This causes distortion in the material, which can lead to cracks when the tip is folded back.

[0004] Furthermore, minor defects that are barely noticeable on two-piece aluminum cans, such as stains caused by rolling oil on the surface of the aluminum sheet material or stains caused by aluminum wear during the drawing and ironing process being pressed onto the surface of the can body, become noticeable as the metal structure is condensed by the extensive diameter reduction process.

[0005] Such defects are detected using a bottle-shaped can screw inspection device, as described in Patent No. 5698608, and the bottle-shaped aluminum cans are recovered as scrap aluminum at a price lower than that of new metal.

[0006] Therefore, manufacturers have implemented various improvements to address these minor defects, but they have not yet been able to eliminate them altogether.

[0007] According to paragraph 0046 of JP2017-526591A, the use of a special aluminum material reduces the rate of defective products during production. However, despite this, the defect rate due to the tip folding process is described as 3%, which is not a good figure for a mass-produced product. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent No. 5698608 [Patent Document 2] Special Publication No. 2017-526591 Summary of the Invention [Problem to be solved by the invention]

[0009] An object of the present invention is to provide a method for efficiently producing stackable cylindrical containers with bottoms made of aluminum or aluminum alloys, which are used as drinking tableware, etc., using bottle-shaped aluminum cans or other containers to be recycled or discarded. [Means for solving the problem]

[0010] The method for producing the stackable container of the present invention can be expressed, for example, as follows.

[0011] (1) A method for manufacturing stackable containers by performing a predetermined process on a cylindrical body with a bottom made of aluminum or an aluminum alloy, which has been integrally formed through at least deep drawing so as to have a dome portion inside the outer periphery of the bottom, and whose opening side has been cut off to achieve a required height, The redrawing process is performed without using a blank holder tool on a redrawing target portion of the bottomed cylindrical body, which is a portion from the bottom end to a predetermined height position that is two-fifths or less of the height of the container after processing; and The method includes performing a diameter expansion process on a diameter expansion target portion of the bottomed cylindrical body, which is the entire portion excluding the re-drawing target portion or a portion from the upper end to a certain height position above the re-drawing target portion, A method for manufacturing stackable containers, characterized in that the expansion process forms at least a predetermined range in the height direction of the expansion target portion into a tapered shape in which the inner diameter and outer diameter decrease downward.

[0012] A bottomed cylindrical body made of aluminum or an aluminum alloy is integrally formed through at least deep drawing so as to have a dome portion inside the outer periphery of the bottom, and the opening side is cut away to achieve the required height. A redrawing process is performed without using a blank holder tool on a redrawing target portion, which is the portion from the lower end to a predetermined height position that is not more than two-fifths of the height of the container after processing. At the same time, a diameter expansion process is performed on a diameter expansion target portion, which is the entire portion of the bottomed cylindrical body excluding the redrawing target portion or the portion from the upper end to a certain height position above the redrawing target portion. The diameter expansion process forms at least a predetermined range in the height direction of the expansion target portion into a tapered shape in which the inner and outer diameters decrease downward, thereby enabling the efficient production of bottomed cylindrical aluminum or aluminum alloy containers that can be stably stacked.

[0013] (2) The manufacturing method according to (1) above, which includes folding back the opening at the top end of the bottomed cylinder outward.

[0014] (3) The manufacturing method according to (2), wherein the redrawing process is carried out after the diameter expansion process and the folding process.

[0015] (4) The redrawing process after the above-mentioned diameter expansion process and folding process is After the diameter expansion process and the folding process, the diameter expansion target portion is further subjected to a diameter expansion process, The manufacturing method according to (3) above, wherein the further diameter expansion process is performed such that, for the portion to be expanded other than the folded-back processed portion, the percentage ratio of the increase in dimension from the maximum outer diameter (D4) before the process to the maximum outer diameter (D5) after the process to the maximum outer diameter (D4) before the process [(D5-D4) / D4] x 100 is 4% or less.

[0016] (5) The redrawing process is performed on the above-mentioned redrawn target portion without using a blank holder tool within a range of 1.0% to 1.5% inclusive of a redrawing rate, which is the percentage of the ratio of the reduction dimension from the outer diameter (D1) before processing to the outer diameter (D6) after processing to the outer diameter (D6) after processing [(D1-D6) / D6] x 100, The manufacturing method according to (3) or (4) above, wherein the diameter expansion treatment and folding treatment are carried out, and then the redrawing treatment is carried out.

[0017] (6) The redrawing process is performed on the redrawn portion without using a blank holder tool, with the redrawing rate being in the range of 1.0% to 1.5%, which is the percentage of the ratio of the reduction dimension from the outer diameter (D1) before processing to the outer diameter (D6) after processing to the outer diameter (D6) after processing [(D1-D6) / D6] × 100, and then the diameter expansion process is performed on the diameter expansion target portion, Further diameter expansion processing and the folding processing are performed on the diameter expansion target portion, The method according to (3) or (4) above, wherein the redrawing treatment is then carried out.

[0018] (7) A jig or tool used to reduce the diameter of the redrawn portion in the redrawing process performed at a redrawing rate of 1.0% or more and 1.5% or less, The manufacturing method according to (5) or (6) above, wherein the redrawing target portion of the bottomed cylindrical body to be processed is subsequently held in the subsequent diameter expansion process and folding process.

[0019] (8) A manufacturing method according to any one of (1) to (7) above, which produces stackable containers in which the wall thickness of the thinnest part of the body of the container that has been subjected to redrawing or diameter expansion is 0.12 mm or more and 0.18 mm or less.

[0020] (9) A manufacturing method according to any one of (1) to (8) above, in which one of the jigs and tools used in at least one of the one or more redrawing processes and one or more diameter expansion processes is separated from the workpiece at least once between the time of contacting the workpiece and the end of the processing.

[0021] (10) A manufacturing method described in any one of (1) to (9) above, wherein the redrawing target portion is a portion of the bottomed cylinder from the lower end to a predetermined height position that is less than one-fourth of the height of the container after processing.

[0022] (11) The method according to any one of (1) to (10) above, wherein the bottomed cylindrical body to be subjected to the predetermined processing has a substantially constant outer diameter.

[0023] (12) The manufacturing method according to any one of (1) to (11) above, wherein the predetermined height position is a position that is two-thirds or less of the height of the container after processing.

[0024] (13) The manufacturing method according to any one of (1) to (12) above, wherein the predetermined range is a range of at least one-fourth of the lower side in the height direction of the diameter expansion target portion.

[0025] (14) The manufacturing method according to any one of (1) to (13) above, wherein the bottomed cylinder to be subjected to the predetermined processing is obtained by at least deep drawing an aluminum alloy sheet, forming a dome portion inside the outer periphery of the bottom, integrally forming it into a bottomed cylinder, and further processing the opening side to reduce at least the outer diameter to form a bottle-shaped can, and then cutting off the opening side at a required height position below the reduced diameter portion on the opening side.

[0026] (15) A manufacturing method according to any one of (1) to (13) above, in which the bottomed cylinder to be subjected to the specified processing is obtained by degreasing and cleaning the bottomed cylinder, drying it, and then decorating and painting the outer surface, painting the bottom, and painting the inner surface.

[0027] (16) The manufacturing method according to any one of (1) to (13) above, wherein the bottomed cylinder to be subjected to the predetermined processing is obtained by subjecting a bottomed cylinder obtained using an aluminum alloy sheet having a resin-coated surface to a heat treatment to remove distortion in the resin coating and re-adhere the resin coating to the aluminum, followed by external decoration and painting. [Effects of the Invention]

[0028] According to the present invention, by utilizing a bottomed cylindrical body made of aluminum or an aluminum alloy, bottomed cylindrical aluminum or aluminum alloy containers that can be stably stacked can be efficiently manufactured using bottle-shaped aluminum cans or other items that are to be recycled or discarded. [Brief explanation of the drawings]

[0029] [Figure 1] FIG. 1 is a front view of a bottle-shaped can made of an aluminum alloy. [Figure 2] 2 is a front view of a bottomed cylindrical body with the upper part cut away below the shoulder of the bottle-shaped can of FIG. 1. FIG. [Figure 3] FIG. 3 is a cross-sectional view of the bottomed cylindrical body of FIG. 2, the lower part of which has been subjected to redrawing processing. [Figure 4] FIG. 3 is a process diagram of a redrawing treatment for the bottomed cylindrical body of FIG. 2. [Figure 5] FIG. 3 is a process diagram of a redrawing treatment for the bottomed cylindrical body of FIG. 2. [Figure 6] FIG. 3 is a process diagram of a redrawing treatment for the bottomed cylindrical body of FIG. 2. [Figure 7] FIG. 4 is a cross-sectional view of the bottomed cylindrical body of FIG. 3 after undergoing diameter expansion treatment. [Figure 8] 4 is a process diagram of a diameter expansion treatment for the bottomed cylindrical body of FIG. 3. [Figure 9] 4 is a process diagram of a diameter expansion treatment for the bottomed cylindrical body of FIG. 3. [Figure 10] 4 is a process diagram of a diameter expansion treatment for the bottomed cylindrical body of FIG. 3. [Figure 11] 4 is a process diagram of a diameter expansion treatment for the bottomed cylindrical body of FIG. 3. [Figure 12] 1 is a cross-sectional view of a bottomed cylindrical body with the upper part cut off below the shoulder of a bottle-shaped can. [Figure 13] FIG. 13 is a cross-sectional view of the bottomed cylindrical body of FIG. 12 after undergoing diameter expansion treatment. [Figure 14] FIG. 14 is a cross-sectional view of the bottomed cylindrical body of FIG. 13 after being folded back. [Figure 15] FIG. 15 is a cross-sectional view of the bottomed cylindrical body of FIG. 14 after undergoing a diameter re-expansion process. [Figure 16] FIG. 16 is a cross-sectional view of the bottomed cylindrical body of FIG. 15 after being subjected to redrawing processing. [Figure 17] FIG. 13 is a cross-sectional view of the bottomed cylindrical body of FIG. 12 after being subjected to redrawing processing. [Figure 18] FIG. 18 is a cross-sectional view of the bottomed cylindrical body of FIG. 17 after undergoing diameter expansion treatment. [Figure 19] FIG. 19 is a cross-sectional view of the bottomed cylindrical body of FIG. 18 after being folded back. [Figure 20] FIG. 20 is a cross-sectional view of the bottomed cylindrical body of FIG. 19 after undergoing a diameter re-expansion process. [Figure 21] 13 is a cross-sectional view of the bottomed cylindrical body of FIG. 12 in a state where the body has been subjected to a re-drawing process and a diameter-expanding process. [Figure 22] 13 is a cross-sectional view showing a state in which the diameter-reducing die used to redraw the bottomed cylindrical body of FIG. 12 is still being used to hold the bottomed cylindrical body. FIG. [Figure 23] 10 is a graph showing an example of a separation motion of a jig or tool. [Figure 24] 24 is a cross-sectional view showing a state in which the bottomed cylindrical body of FIG. 12 is subjected to a redrawing process by separating the jig tool so as to correspond to FIG. 23. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0030] [1] An embodiment of the present invention will be described with reference to the drawings.

[0031] (1) First example

[0032] 1 to 11 all relate to a method for manufacturing stackable containers as a first embodiment of the present invention.

[0033] (1-1) A bottomed cylinder that is processed as required

[0034] The bottle-shaped can 10 shown in FIG. 1 is manufactured by deep drawing, redrawing, ironing, etc., of a 3104 series aluminum alloy sheet, forming a dome portion 12 inside the outer periphery of the bottom, and integrally forming a body portion 14 into a bottomed cylindrical shape with a thickness of less than 0.3 mm. After degreasing and drying, the outer surface is decorated and painted with an epoxy paint, and the inner surface is painted. Thereafter, the outer diameter of the opening side is reduced, and necking, threading, folding back, etc. are performed to form the bottle-shaped can 10.

[0035] The outer periphery of the bottom, that is, the outer peripheral portion of the dome portion 12, is an annular outer periphery portion 16 having a U-shaped annular cross section in the radial direction.

[0036] For bottle-shaped cans 10 having defects at or above the position where the diameter narrowing toward the opening side begins, the opening side (i.e., the upper side) is cut away at a required height position C below the narrowed diameter portion on the opening side (below the shoulder portion 18), to obtain a one-piece, bottomed cylindrical body 20 made of a 3104 series aluminum alloy, as shown in Figure 2, in which the body portion 14 is less than 0.3 mm thick and has a constant outer diameter.

[0037] (1-2) Redrawing process

[0038] The redrawing target portion 20a of the obtained bottomed cylindrical body 20 is subjected to a redrawing process (redrawing processing) without using a blank holder jig. Fig. 3 shows the bottomed cylindrical body 20 after the redrawing process, including the folded portion 20b that will be formed by the subsequent folding process (curling).

[0039] The redraw target portion 20a is the portion from the bottom end of the bottomed cylinder 20 to a position (predetermined height position) at a height (HL) that is approximately one-fifth of the height (HF) of the container after predetermined processing including folding back processing of the upper end opening 20c. The predetermined height position is a position higher than the upper end position of the dome portion 12.

[0040] 4 to 6, the annular outer peripheral portion 16 at the bottom end of the bottomed cylinder 20 is supported upward by a disk-shaped support body 40, and the circular upper end opening 20c of the bottomed cylinder 20 is fitted downwardly into a pressing body 50 having a truncated cone-shaped protrusion 50b (with air supply holes 50c) formed inside an annular plate-shaped portion 50a so as to decrease in diameter downward, and is pressed downward. In this state, the lower portion of the bottomed cylinder 20 is inserted into the reducing die 30, whereby the portion 20a to be redrawn of the bottomed cylinder 20 is redrawn without using a blank holder jig.

[0041] The percentage ratio of the reduction dimension from the outer diameter (D1) before processing to the minimum outer diameter (D2) after processing for the re-drawing target portion 20a to the minimum outer diameter (D2) after processing [(D1-D2) / D2] x 100 is approximately 3% (excluding the outer diameter of the annular outer peripheral portion 16 (HB portion) at the bottom end of the container where the dome portion 12 is provided, which has a U-shaped radial cross section).

[0042] (1-3) Diameter expansion process

[0043] After the redrawing process, the diameter expansion target portion 60 of the bottomed cylindrical body 20 is subjected to a diameter expansion process (diameter expansion processing). Fig. 7 shows the bottomed cylindrical body 20 after the diameter expansion process, including the folded portion 20b formed by the subsequent folding processing.

[0044] The expansion target portion 60 is the portion from the upper end of the bottomed cylinder 20 to a height position (a certain height position above the re-draw target portion 20a) that is approximately three-tenths of the height (HF) of the container after a specified processing including folding back processing of the upper end opening 20c.

[0045] In this example, the diameter expansion process is carried out three times.

[0046] The first diameter expansion process is performed using a diameter expansion jig 70 having a portion where the outer diameter tapers downward at a middle position in the vertical axial direction and a constant outer diameter portion where the diameter tapers downward. That is, as shown in Figures 8 to 11, the annular outer peripheral portion 16 at the bottom end of the bottomed cylinder 20 is received upward by the disk-shaped receiving body 40, and the diameter expansion jig 70 is inserted downward from the circular upper end opening 20c of the bottomed cylinder 20 (with the air supply passage 72 for preventing buckling during processing and for demolding after processing) to expand approximately the upper half of the diameter expansion target portion 60 of the bottomed cylinder 20.

[0047] Next, second and third diameter expansion processes are performed using different diameter expansion jigs, and as a result, the inner and outer diameters of the entire diameter expansion target portion 60 are expanded, as shown in Fig. 7. Of the diameter expansion target portion 60, a portion within a range of approximately eight-ninths of the lower side in the height direction (a predetermined range portion) is formed into a tapered shape in which the inner and outer diameters decrease downward.

[0048] The percentage of the ratio of the increase in the outer diameter (D1) before processing to the maximum outer diameter (D3) after the diameter expansion process for the expansion target portion 60 to the outer diameter (D1) before processing [(D3-D1) / D1] x 100 is approximately 9%.

[0049] (1-4) Folding

[0050] After the diameter expansion process, the opening at the top end of the bottomed cylinder 20 is folded back outward to form a folded back portion 20b.

[0051] (1-5) The stackable cylindrical container with a bottom made of a 3104 series aluminum alloy thin plate thus manufactured, which can be used as a tumbler or other drinking tableware, is essentially a body of revolution about a vertical axis, and the wall thickness of the body 14 is thin, less than 0.3 mm.

[0052] (2) Second example

[0053] 12 to 16 each relate to a method for manufacturing stackable containers as a second embodiment of the present invention.

[0054] 12 to 16, the same reference numerals as those in FIGS. 1 to 11 indicate the corresponding objects or parts in the first example.

[0055] (2-1) A bottomed cylinder that is processed as required

[0056] 12 shows a one-piece, bottomed cylinder 20 made of a 3104 series aluminum alloy obtained in the same manner as in Example 1. However, its body 14 is thinner, with the thickness of its thinnest part being 0.12 mm or more and 0.18 mm or less.

[0057] (2-2) Diameter expansion process

[0058] The diameter expansion target portion of the bottomed cylinder 20 shown in FIG. 12 is subjected to diameter expansion treatment (diameter expansion processing) two or more times to obtain the bottomed cylinder 20 after diameter expansion treatment shown in FIG.

[0059] As shown in Figure 16, the expansion target portion 60 is the portion from the upper end of the bottomed cylinder 20 to a certain height position slightly above the predetermined height (HL) position, which is the upper end of the re-draw target portion 20a, within the height (HF) of the container after a predetermined processing including folding back processing of the upper end opening 20c.

[0060] (2-3) Folding

[0061] After the diameter expansion process, the opening at the top end of the bottomed cylinder 20 is folded back outward (curled) to form a folded back portion 20b as shown in FIG.

[0062] (2-4) Re-expansion process

[0063] After the folding process, the diameter expansion target portion 60 is subjected to a diameter expansion process once again, thereby obtaining the bottomed cylindrical body 20 after the diameter expansion process shown in FIG.

[0064] In this re-expansion process, for the expansion target portion other than the folded-back processed portion, the percentage ratio of the increase in dimension from the maximum outer diameter (D4) before the process to the maximum outer diameter (D5) after the process to the maximum outer diameter (D4) before the process [(D5-D4) / D4] x 100] is 4% or less.

[0065] (2-5) Redrawing process

[0066] The redrawing target portion 20a of the bottomed cylindrical body 20 after the re-expansion process is subjected to a redrawing process without using a blank holder jig, thereby obtaining the container shown in FIG.

[0067] The redraw target portion 20a is the portion extending from the bottom of the bottomed cylinder 20 to a position (predetermined height position) at a height (HL) that is approximately one-third of the height (HF) of the container after predetermined processing, including folding back the upper end opening 20c. The predetermined height position is higher than the upper end position of the dome portion 12.

[0068] (2-6) The thus-manufactured stackable cylindrical container made of a 3104 series aluminum alloy sheet and having a bottom, which can be used as a tumbler or other drinking utensils, is essentially a body of revolution about a vertical axis, and the wall thickness of the thinnest part of the body 14 is 0.12 mm or more and 0.18 mm or less.

[0069] Of the diameter expansion target portion 60, a portion (predetermined portion) in a range of nearly 90% on the lower side in the height direction is formed in a tapered shape in which the inner diameter and outer diameter decrease downward.

[0070] For the diameter expansion target portion 60, the increase in the outer diameter (D1) before processing to the maximum outer diameter (D3) after the diameter expansion processing other than the folded-back processed portion, and the ratio of the increase in the outer diameter (D1) before processing to the outer diameter (D1) before processing, [(D3-D1) / D1] x 100, is approximately 12%.

[0071] For the redrawing target portion 20a, the percentage ratio of the reduction dimension from the outer diameter (D1) before processing to the minimum outer diameter (D2) after processing to the minimum outer diameter (D2) after processing [(D1-D2) / D2] x 100 is approximately 7% (excluding the outer diameter of the annular outer peripheral portion 16 (HB portion) at the bottom end of the container where the dome portion 12 is provided, which has a U-shaped radial cross section).

[0072] (3) Third Example

[0073] 12, 17 to 20, and 16 all relate to a method for manufacturing stackable containers as a third embodiment of the present invention.

[0074] 12, 17 to 20, and 16, the same reference numerals as those in FIGS. 1 to 11 indicate the corresponding objects or parts in the first example.

[0075] The third example is similar to the second example in (2) above, except for some steps.

[0076] The process in which the third example differs from the second example is that, before the diameter expansion process (2-2) above, the redrawing process is performed once on the redrawing target portion 20a of the bottomed cylinder 20 shown in Figure 12 without using a wrinkle holder tool, with the redrawing rate, which is the percentage ratio of the reduction dimension from the outer diameter (D1) before processing to the minimum outer diameter (D6) after processing to the minimum outer diameter (D6) after processing, [(D1-D6) / D6] x 100, in the range of 1.0% to 1.5%.

[0077] The bottomed cylindrical body 20 thus obtained, which has been subjected to the redrawing process shown in FIG. 17, is subjected to the diameter expansion process described in (2-2) above, thereby obtaining the bottomed cylindrical body 20 after the diameter expansion process shown in FIG. 18. Next, the folding process (2-3) is performed to provide the folded portion 20b shown in FIG. 19. Next, the re-expansion process (2-4) is carried out to obtain the bottomed cylindrical body 20 after the re-expansion process shown in FIG. 20. Further, by carrying out the redrawing process of (2-5) above, a cylindrical container with a bottom conforming to the description of (2-6) above can be manufactured as shown in FIG.

[0078] (4) Fourth Example

[0079] Fig. 21 relates to a method for manufacturing stackable containers as a fourth embodiment of the present invention. In Fig. 21, the same reference numerals as in Figs. 1 to 11 indicate the corresponding items or parts in the first embodiment.

[0080] The fourth example is similar to the third example in (3) above, except for some steps.

[0081] The steps in which the fourth example differs from the third example in (3) above are: 21, the redrawing target portion 20a of the bottomed cylinder 20 shown in Fig. 12 is redrawn once without using a blank holder tool within a redrawing ratio range of 1.0% to 1.5%, which is the ratio of the reduction dimension from the outer diameter (D1) before processing to the minimum outer diameter (D6) after processing to the minimum outer diameter (D6) after processing, [(D1-D6) / D6] x 100. At the same time, the diameter expansion target portion 60 of the same bottomed cylinder 20 is expanded once, and then a further diameter expansion process is performed on the diameter expansion target portion 60. The positions of D1 and D6 are as shown in Fig. 17.

[0082] The bottomed cylindrical body 20 that has been subjected to the redrawing process and the diameter expansion process is provided with a folded portion 20b as shown in FIG. 19 by the folding process as described above in (2-3). Next, the re-expansion process as described above in (2-4) is carried out to obtain a bottomed cylindrical body 20 after the re-expansion process as shown in FIG. 20. Further, by carrying out the redrawing process as in (2-5) above, a cylindrical container with a bottom conforming to the description in (2-6) above can be manufactured as shown in FIG.

[0083] (5) Fifth Example

[0084] Fig. 22 relates to a method for manufacturing stackable containers as a fifth example of an embodiment of the present invention. In Fig. 22, the same reference numerals as in Figs. 1 to 11 indicate the corresponding items or parts in the first example.

[0085] In the fifth example, the diameter reducing die 30 (jig tool) used to reduce the diameter of the redrawing target portion 20a in the redrawing process performed in the third example (3) or the fourth example (4) above, where the redrawing rate is in the range of 1.0% or more and 1.5% or less, is subsequently used to hold the redrawing target portion 20a of the bottomed cylindrical body 20 to be processed in the subsequent diameter expansion process and folding process, as shown in Figure 22.

[0086] (6) Sixth Example

[0087] 23 and 24 relate to a method for manufacturing stackable containers as a sixth embodiment of the present invention.

[0088] In FIG. 23, which is a graph showing an example of the tool separation motion, the horizontal axis represents the cam curve [degrees] and the vertical axis represents the tool position [mm].

[0089] In FIG. 24, the same reference numerals as those in FIGS. 1 to 11 indicate the corresponding objects or parts in the first example.

[0090] In the sixth example, in each of the first to fifth examples above, in at least one or more of the redrawing processes and one or more expansion processes (for example, all of the processes, or processes other than one or two), one of the jigs and tools used is separated at least once between the time it comes into contact with the processed portion of the bottomed cylinder 20 to be processed and the time the processing is completed.

[0091] The machining start point and machining end point in FIG. 23 correspond to the machining start point and machining end point in FIG. 24, respectively.

[0092] In the example of Figure 23, as shown in Figure 24, the reducing die 30 (jig) is raised to the starting point of processing, and then the reducing die 30 is raised slightly to continue processing, and then the reducing die 30 is moved away (lowered) to the position of the starting point of processing, and then the reducing die 30 is raised again to reach the end point of processing, and there is only one movement away from the time the reducing die 30 contacts the processed portion of the bottomed cylinder 20 until the end of the processing process.

[0093] [2] The embodiments of the present invention will be further described, including embodiments other than those described above.

[0094] The manufacturing method of the present invention is a method for producing bottomed cylindrical containers that can be stacked and used as tumblers or other drinking tableware by subjecting bottomed cylindrical bodies made of aluminum or aluminum alloy to predetermined processes including redrawing and diameter expansion. Examples of bottomed cylindrical bodies that can be subjected to the predetermined processes include, but are not limited to, bottomed cylindrical bodies obtained from recycled or discarded products and newly manufactured bottomed cylindrical bodies.

[0095] (1) Bottomed cylinder

[0096] The bottomed cylinder that is subjected to the predetermined processing in the manufacturing method of the present invention is made of aluminum or an aluminum alloy (preferably 3004 series or 3104 series), and can be made of an aluminum or aluminum alloy thin plate.

[0097] It is preferred that both or either of the inner and outer surfaces of the bottomed cylinder, or all or part of the entire surface including the inner and outer surfaces, be coated with, for example, an epoxy-based, acrylic-based, polyester-based or other synthetic resin by painting, extrusion lamination or other means, but this is not necessarily limited to this.

[0098] The bottomed cylinder to be subjected to this predetermined processing can be made to have a substantially constant outer diameter (for example, a constant outer diameter except for the lower end), and can be made to be such that multiple identical cylinders cannot be stacked on top of each other. It is preferable that this bottomed cylinder is a body of revolution substantially centered on an axis in the vertical direction.

[0099] The outer diameter of the bottomed cylinder can be, for example, 57.0 to 66.5 mm, but is not limited to this.

[0100] (1-1) For example, by subjecting an aluminum alloy sheet to at least deep drawing (generally at least deep drawing, redrawing, and ironing), forming a dome portion inside the outer periphery of the bottom, and then cutting away the opening side to achieve the required height, a one-piece (seamless) bottomed cylinder made of aluminum alloy, i.e., a bottomed cylinder that is subjected to the required processing in the manufacturing method of the present invention (preferably one in which the barrel portion is thinned [for example, to a thickness of less than 0.3 mm]. The thickness of the thinnest part of the barrel portion can be, for example, 0.12 mm to 0.18 mm), can be obtained by integral molding. The required height is the dimension in the axial direction from the lower end, and is preferably constant around the entire circumference of the opening.

[0101] In the manufacturing method of the present invention, it is preferable that the predetermined processing be carried out on a bottomed cylindrical body that has been subjected to the following treatment (a) or (b).

[0102] (a) The bottomed cylinder obtained as described above is degreased and cleaned, then dried (after Zr chemical conversion treatment if necessary), and then the outer surface is decorated and painted, the bottom is painted, and the inner surface is painted to obtain the bottomed cylinder.

[0103] (b) A bottomed cylinder obtained in the same manner as above, except that the aluminum alloy sheet used has a resin coating on the surface. The bottomed cylinder is then subjected to a heat treatment to remove any distortion in the resin coating and re-adhere the resin coating to the aluminum, followed by exterior decoration and painting, bottom painting, and interior painting.

[0104] (1-2) For example, an aluminum alloy sheet (preferably one whose surface is painted or coated with other resins) may be subjected to at least deep drawing (generally at least deep drawing, redrawing, and ironing), and a dome portion may be provided inside the outer periphery of the bottom to form a bottomed cylindrical integral body. The bottomed cylindrical body may then be further processed to reduce the outer diameter of the opening side (and, if necessary, be subjected to flanging, threading, tip folding, etc.) to form a bottle-shaped can (or a can which has been further exterior-decorated and painted, and has a bottom painted, etc.). The opening side (i.e., the upper side) may be trimmed at a required height below the reduced diameter portion of the opening side (below the shoulder), thereby forming a one-piece (seamless) bottomed cylinder made of aluminum alloy, i.e., a bottomed cylinder to which the specified processing is applied in the manufacturing method of the present invention (preferably one whose body portion is thinned [for example, to a thickness of less than 0.3 mm]. The thickness of the thinnest part of the body may be, for example, 0.12 mm or more and 0.18 mm or less).

[0105] The bottle-shaped cans to be subjected to this treatment are preferably those that are to be recycled or discarded without being used because they have defects at the position where the diameter starts to decrease toward the opening or above that, such as defects caused by the folding process at the tip of the opening.

[0106] In addition, in the case of a bottomed cylindrical can body to which a top lid or the like is joined by crimping or the like, if the top lid or the like is to be recycled or discarded without being used because it has a defect above the required height, the upper side can be similarly cut off to obtain a bottomed cylindrical body that can be similarly processed using the manufacturing method of the present invention.

[0107] (2) Redrawing process

[0108] Of the bottomed cylindrical body that has been subjected to the specified processing that can be obtained as described above, the portion from the lower end to a specified height position that is less than two-fifths of the height of the container after processing (i.e., the portion to be redrawn) is subjected to a redrawing process (redrawing processing) without using a wrinkle holder tool.

[0109] The height of the container after processing refers to the height of the container in a state where no further changes are substantially made to the height of the container; for example, if the opening at the top end is folded over, it refers to the height of the container after the folding over.

[0110] The redraw target portion is the portion from the bottom of the bottomed cylinder to a predetermined height position that is two-fifths or less of the height of the container after processing (depending on various conditions, it may be the portion to a predetermined height position that is one-quarter or less of the height of the container after processing). Examples of the predetermined height position include a height position that is two-fifths of the height of the container after processing, a height position that is one-quarter of the height of the container after processing, and a height position that is one-sixth of the height of the container after processing. It is preferable that the predetermined height position be higher than the upper end position of the dome portion so that the containers can be fully stacked on top of each other, but this is not necessarily limited to this.

[0111] The redrawing of the redraw target portion can be carried out once or twice or more times without using a blank holder tool.

[0112] The percentage ratio of the reduction dimension from the outer diameter (D1) before processing to the outer diameter (D2) after processing for the re-drawn portion, [(D1-D2) / D2] x 100, to the outer diameter (D2) after processing, can be, for example, 1% or more and 6% or less, but is not limited to this (however, this does not include the outer diameter of the annular outer peripheral portion at the bottom end of the container where the dome portion is provided, which has a U-shaped radial cross section [the outer diameter of the portion that is smaller in diameter than other parts of the re-drawn portion]).

[0113] (3) Diameter expansion

[0114] (3-1) Of the bottomed cylinder that has been subjected to the specified processing that can be obtained as described above, an expansion process (expansion processing) is performed on the entire portion excluding the re-drawing target portion (i.e., the portion above the re-drawing target portion) or on the portion from the upper end of the bottomed cylinder to a certain height position above the re-drawing target portion (i.e., the expansion target portion).

[0115] The diameter expansion target portion is the entire portion of the bottomed cylinder above the redraw target portion, or the portion of the bottomed cylinder from the upper end to a certain height position above the redraw target portion.

[0116] The fixed height position can be, for example, a position at or below two-thirds the height of the container after processing. To ensure sufficient overlapping of the containers, the fixed height position is preferably a position at or below one-half the height of the container after processing. Depending on the height of the portion to be redrawn, the fixed height position can be a position at or below two-fifths the height or one-third the height.

[0117] It is desirable to perform the diameter expansion treatment on the diameter expansion target portion two or three or more times. The diameter expansion treatment can be performed before or after the re-drawing treatment.

[0118] (3-2) The diameter expansion process is a process of forming at least a predetermined range in the height direction of the diameter expansion target portion into a tapered shape in which the inner diameter and outer diameter decrease in diameter downward (the taper angle may change depending on the vertical position).

[0119] The specified range portion is, for example, the entire diameter expansion target portion, or a range of at least one-fourth of the lower side in the height direction of the diameter expansion target portion, preferably at least one-third of the range, more preferably at least one-half of the range, and even more preferably at least two-thirds of the range.

[0120] The percentage ratio of the increase in the outer diameter (D1) before processing to the maximum outer diameter (D3) after the expansion process for the expansion target portion to the outer diameter (D1) before processing [(D3-D1) / D1] x 100 can be, for example, 4% or more and 10% or less, but is not limited to this.

[0121] Furthermore, it is desirable that the portion to be enlarged after the predetermined processing that has been carried out through the enlargement process does not have a portion where the inner diameter decreases upward.

[0122] (4) Folding

[0123] The opening at the top end of the bottomed cylindrical body that has been subjected to the predetermined processing as described above is preferably folded back (curled) outward. Generally, the folding back is performed after the diameter expansion process.

[0124] (5) Suitable manufacturing method example

[0125] (5-1) In the manufacturing method of the present invention, the redrawing treatment of the redrawing target portion is preferably carried out after the diameter expansion treatment and the folding back process.

[0126] This is because the occurrence of wrinkles in the body of the bottomed cylindrical body during the redrawing process can be effectively prevented, thereby reducing the rate of defective products.

[0127] This also broadens the range of heights from the bottom end of the bottomed cylinder that can be redrawn without using a blank holder (the range of the redrawn target portion can be broadened, for example, from the portion of the bottomed cylinder from the bottom end to a predetermined height position that is not more than one-fourth of the height of the processed container to a portion of the bottomed cylinder to a predetermined height position that is not more than two-fifths of the height of the processed container). Broadening the range of heights from the bottom end of the bottomed cylinder that can be redrawn reduces the height when multiple containers are stacked together (and therefore reduces the space required for storage, transportation, etc.).

[0128] Furthermore, it is also possible to manufacture a container in which the wall thickness of the portion that has been subjected to the redrawing or diameter expansion process is thin, for example, from 0.12 mm to 0.18 mm at the thinnest portion.

[0129] The diameter expansion treatment is preferably carried out two or more times, and the folding back treatment may be carried out one or more times. Generally, the folding back treatment is carried out after the diameter expansion treatment.

[0130] It is also preferable that the redrawing process be carried out two or more times.

[0131] The percentage ratio of the increase in the dimension from the outer diameter (D1) before processing to the maximum outer diameter (D3) after the expansion process for the expansion target portion to the outer diameter (D1) before processing [(D3-D1) / D1] x 100 can be, for example, 4% or more and 14% or less, but is not limited to this.

[0132] The percentage ratio of the reduction dimension from the outer diameter (D1) before processing to the outer diameter (D2) after processing for the re-drawn portion, [(D1-D2) / D2] x 100, can be, for example, 1% or more and 11% or less (excluding the outer diameter of the annular outer peripheral portion at the bottom end of the container where the dome portion is provided, which has a U-shaped radial cross section [the outer diameter of the portion that is smaller in diameter than other parts of the re-drawn portion]).

[0133] (5-2) In the above (5-1), the redrawing process after the diameter expansion process and the folding process is performed as follows: After the diameter expansion process and the folding process, the diameter expansion target portion is further subjected to a diameter expansion process, It is preferable that the further diameter expansion process is such that, for the portion to be expanded other than the folded-back processed portion, the percentage ratio of the increase in dimension from the maximum outer diameter (D4) before the process to the maximum outer diameter (D5) after the process to the maximum outer diameter (D4) before the process [(D5-D4) / D4] x 100 is 4% or less.

[0134] In this case, the rate at which the material of the bottomed cylindrical body breaks can be effectively reduced.

[0135] The treatment in which the percentage of the ratio is 4% or less is preferably a single diameter expansion treatment, but may also be a multiple diameter expansion treatment.

[0136] (5-3) The redrawing target portion in (5-1) or (5-2) above is subjected to a redrawing process (preferably in a single process) without using a blank holder tool, with the redrawing rate being in the range of 1.0% to 1.5%, which is the percentage [(D1-D6) / D6] × 100 of the ratio of the reduced dimension from the outer diameter (D1) before processing to the outer diameter (D6) after processing, It is preferable that the diameter expansion process and folding process are carried out, and then the redrawing process is carried out.

[0137] In this case, the occurrence of wrinkles in the body of the bottomed cylindrical body during the re-drawing process performed before and after the diameter expansion process and the folding process can be effectively suppressed, thereby reducing the rate of defective products.

[0138] This also widens the range of heights from the bottom end of the bottomed cylindrical body that can be redrawn without using a blank holder jig. Widening the range of heights from the bottom end of the bottomed cylindrical body that can be redrawn leads to a reduction in the height of the containers that are manufactured when multiple containers are stacked together.

[0139] Furthermore, the container to be manufactured can have a thin wall thickness of, for example, 0.12 mm or more and 0.18 mm or less at the thinnest part where the redrawing or diameter-expanding process has been performed.

[0140] (5-4) For the redrawing target portion in (5-1) or (5-2) above, a redrawing rate, which is the percentage of the ratio of the reduced dimension from the outer diameter (D1) before processing to the outer diameter (D6) after processing, [(D1-D6) / D6] × 100, is in the range of 1.0% to 1.5%, without using a blank holder tool, and then a diameter expansion process is performed on the diameter expansion target portion, Further diameter expansion processing and the folding processing are performed on the diameter expansion target portion, Thereafter, the above-mentioned redrawing process can be carried out.

[0141] In this case, the occurrence of wrinkles in the body of the bottomed cylindrical body during the further diameter expansion process and the re-drawing process performed before and after the folding process can be effectively suppressed, thereby reducing the rate of defective products.

[0142] (5-5) In the above (5-3) or (5-4), a jig or tool used to reduce the diameter of the redrawing target portion in the redrawing process performed at a redrawing rate in the range of 1.0% or more and 1.5% or less is It is preferable that the redrawing member be used subsequently to hold the redrawing target portion of the bottomed cylindrical body, which is the processing target, in the subsequent diameter expansion process and folding process.

[0143] In this case, even if the wall thickness of the bottomed cylindrical body to be processed is thinner, it is possible to effectively prevent buckling from occurring during the diameter expansion process or folding process.

[0144] (5-6) In the manufacturing method of the present invention, it is preferable that in at least one or more of the re-drawing processes and the one or more diameter expansion processes (for example, all of the processes or processes other than one or two), one of the jigs and tools used is separated at least once between the time when it comes into contact with the workpiece to be processed and the time when the processing is completed.

[0145] By separating one of the jigs and tools used in each process at least once between the time it comes into contact with the workpiece to be processed and the time the processing is completed, the center position (or central axis) of the bottomed cylinder to be processed that comes into contact with the tool again after separation can be aligned (e.g., matched more accurately) with the center position (or central axis) of the jigs and tools, effectively reducing the rate at which cracks and wrinkles occur in the bottomed cylinder.

[0146] (6) The stackable cylindrical container with a bottom manufactured by the present invention, which can be used as a tumbler or other drinking utensil, is preferably a container that is essentially a body of revolution about a vertical axis. The wall thickness of the body of the container can be, for example, less than 0.3 mm, and the wall thickness of the thinnest part of the body can be, for example, 0.12 mm to 0.18 mm. Furthermore, the cylindrical container with a bottom manufactured by the present invention can have a dome portion inside the outer periphery of the bottom, with the aim of ensuring at least practical rigidity as a container. Examples of the shape of the dome portion include, but are not limited to, a concave lower opening with an upwardly convex curved surface; a concave lower opening with a cylindrical or truncated conical outer periphery and an upwardly convex curved upper surface; and a concave lower opening with an approximately conical or truncated conical shape. In addition to improving the rigidity of the bottom, the dome portion can be effective in, for example, reducing the contact area of ​​the bottom during the manufacturing process (e.g., when transported by a conveyor), thereby minimizing scratches and other damage to the bottom. [Explanation of symbols]

[0147] 10 Bottle-shaped cans 12 Dome section 14 Torso 16 Circular outer periphery 18 Shoulder 20 Bottomed cylinder 20a Redraw target area 20b Folded part 20c top opening 30 Reducing die 40 Disc-shaped receiving body 50 Pressurizing body 50a Annular plate-shaped portion 50b frustum-shaped convex part 50c Air supply hole 60 Expansion target part 70 Expanding tool 72 Air supply passage C. Required height position D1 Outer diameter before machining D2 Outer diameter after machining D3 Maximum outer diameter after expansion D4 Maximum outer diameter before re-expansion processing D5 Maximum outer diameter after re-expansion processing D6 Minimum outer diameter after redrawing before diameter expansion HF: Height of the container after processing HL specified height HB: Height of the outer circumference of the ring

Claims

1. A method for manufacturing stackable containers by performing a predetermined process on a bottomed cylindrical body made of aluminum or an aluminum alloy, which is integrally formed through at least deep drawing so as to have a dome portion inside the outer periphery of the bottom, and whose opening side is cut away to achieve a required height, the method comprising: A redrawing process is performed on a redrawing target portion of the bottomed cylindrical body, which is a portion from the lower end to a predetermined height position that is two-fifths or less of the height of the container after processing, without using a wrinkle holder tool. By the re-drawing process, a tapered portion is formed in which the inner diameter and the outer diameter of the re-drawing target portion decrease downward; and The method includes performing a diameter expansion process on a diameter expansion target portion of the bottomed cylindrical body, which is the entire portion excluding the re-drawing target portion or a portion from the upper end to a certain height position above the re-drawing target portion, A method for manufacturing stackable containers, characterized in that the expansion process forms at least a predetermined range in the height direction of the expansion target portion into a tapered shape in which the inner diameter and outer diameter decrease downward.

2. 2. The method according to claim 1, further comprising the step of folding back the opening at the top end of said bottomed cylinder.

3. 3. The manufacturing method according to claim 2, wherein the redrawing process is carried out after the diameter expansion process and the folding process.

4. The redrawing process after the above-mentioned diameter expansion process and folding process is After the diameter expansion process and the folding process, the diameter expansion target portion is further subjected to a diameter expansion process, 4. The manufacturing method according to claim 3, wherein the further diameter expansion process is performed such that, for the portion to be expanded other than the folded-back processed portion, the percentage ratio of the increase in dimension from the maximum outer diameter (D4) before the process to the maximum outer diameter (D5) after the process to the maximum outer diameter (D4) before the process [(D5-D4) / D4] x 100 is 4% or less.

5. The redrawing process is performed on the redrawn target portion without using a blank holder tool within a range of 1.0% to 1.5% inclusive of a redrawing rate, which is the percentage [(D1-D6) / D6] x 100 of the ratio of the reduced dimension from the outer diameter (D1) before processing to the outer diameter (D6) after processing.

5. The manufacturing method according to claim 3, wherein the diameter expansion process and folding process are carried out, and then the redrawing process is carried out.

6. The redrawing target portion is subjected to a redrawing process without using a blank holder tool within a range of 1.0% to 1.5% inclusive, where the redrawing rate is the percentage [(D1-D6) / D6] x 100 of the ratio of the reduction dimension from the outer diameter (D1) before processing to the outer diameter (D6) after processing to the outer diameter (D6). At the same time, the diameter expansion target portion is subjected to a diameter expansion process. Further diameter expansion processing and the folding processing are performed on the diameter expansion target portion, 5. The method according to claim 3, wherein the redrawing treatment is then carried out.

7. A jig or tool used to reduce the diameter of the redrawing target portion in the redrawing process performed at a redrawing rate in the range of 1.0% to 1.5%, 7. The manufacturing method according to claim 5, wherein the redrawing target portion of a bottomed cylindrical body is subsequently held in the enlarged diameter treatment and folded back treatment.

8. The manufacturing method according to any one of claims 1 to 7, wherein the method produces stackable containers in which the wall thickness of the thinnest part of the body of the container that has been subjected to redrawing or diameter expansion processing is 0.12 mm or more and 0.18 mm or less.

9. 9. The manufacturing method according to claim 1, wherein in at least one of the one or more redrawing processes and the one or more diameter expansion processes, one of the jigs and tools used is separated at least once between the time when it comes into contact with the workpiece to be processed and the time when the processing is completed.

10. A manufacturing method according to any one of claims 1 to 9, wherein the portion to be redrawn is a portion of the bottomed cylinder from the lower end to a predetermined height position that is less than one-fourth of the height of the container after processing.

11. 11. The method according to claim 1, wherein the bottomed cylindrical body to be subjected to the predetermined processing has a substantially constant outer diameter.

12. 12. The method according to claim 1, wherein the predetermined height position is a position that is equal to or lower than two-thirds of the height of the container after processing.

13. 13. The manufacturing method according to claim 1, wherein the predetermined range portion is a range of at least one-fourth of the lower side in the height direction of the diameter expansion target portion.

14. The manufacturing method according to any one of claims 1 to 13, wherein the bottomed cylindrical body to be subjected to the predetermined processing is obtained by at least deep drawing an aluminum alloy sheet, forming a dome portion inside the outer periphery of the bottom, integrally molding it into a bottomed cylindrical shape, and further processing the opening side to reduce at least the outer diameter to form a bottle-shaped can, and then cutting off the opening side at a required height position below the reduced diameter portion on the opening side.

15. A manufacturing method described in any one of claims 1 to 13, wherein the bottomed cylinder to be subjected to the specified processing is obtained by degreasing and cleaning the bottomed cylinder, drying it, and then decorating and painting the exterior, painting the bottom, and painting the interior.

16. The manufacturing method according to any one of claims 1 to 13, wherein the bottomed cylinder to be subjected to the predetermined processing is obtained by subjecting a bottomed cylinder obtained using an aluminum alloy sheet having a resin-coated surface to a heat treatment to remove any distortion in the coating resin and re-adhere the coating resin to the aluminum, followed by external decoration and painting.

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