Molded body manufacturing method, molded body manufacturing device, and molded body

Abstract

To provide a method for manufacturing a molded body having an inclined side wall with excellent beauty with fewer processing steps.SOLUTION: A method for manufacturing a molded body, which has a bottom and a shank, of which a top face opens, and which has a shape that expands outward as the shank moves toward the top face side, by using a drawing member including a pair of male mold and female mold, includes: a process in which a tabular work-piece is placed in the drawing member so that a first face of the work-piece faces the male mold, and a second face opposite to the first face thereof faces the female mold; and a process in which the work-piece is drawn while applying a pressing force by a fluid to the same in parallel to both faces of the first face and the second face.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a molded body, an apparatus for manufacturing a molded body, and a molded body.

Background Art

[0002] Conventionally, it has been known that a molded body in which a bottom is formed at one end of a cylindrical body and an opening is formed at the other end is manufactured by drawing using a male die and a female die by pressing. Among them, in particular, a so-called tapered container in which the diameters of the bottom and the opening are different and the side wall portion is an inclined surface (tapered surface) is also known.

[0003] In such drawing for forming an inclined surface, since the clearance (drawing clearance) between the male die and the female die becomes large, material restraint is lost during the drawing process and wrinkles are generated on the side wall portion. The larger the clearance and the smaller the relative plate thickness indicated by the blank diameter and the thickness of the workpiece, the more likely side wall wrinkles are to occur.

[0004] As a method for manufacturing a molded body having an inclined side wall portion, for example, Patent Document 1 discloses a method of forming a stepped container by multiple drawing processes and then correcting the side wall portion to an inclined surface by sandwiching it between a male die and a female die having an inclined surface. Patent Document 2 discloses a method of setting a drawing clearance within a range where side wall wrinkles do not occur and connecting the inclined side wall portions by multiple tapered drawings. Patent Document 3 discloses a method of forming a cylindrical drawn can having no inclination in the side wall portion as a first step and then inclining the side wall portion step by step while enlarging it using a die for diameter expansion.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Disclosure of the Invention

Problems to be Solved by the Invention

[0006] In the prior art, when manufacturing a tapered container, it has been difficult to manufacture a thin side wall portion at high speed with few processing steps. That is, in the method of manufacturing a tapered container by gradually inclining the side wall portion in multiple steps as described above, as the thickness of the workpiece becomes thinner, the limit clearance without side wall wrinkles becomes smaller, so the number of manufacturing steps increases. Due to the number of manufacturing steps, the equipment becomes large-scale, and it has been difficult to manufacture a thin-walled tapered container at high speed while reducing the number of steps.

[0007] Also, in the process of inclining the side wall portion by a plurality of steps, there has been a problem that circumferential processing marks are generated at the joints of each step according to the number of inclination steps. And these days, it goes without saying that excellent aesthetics in the side wall portion of the molded body affect the sales of the product, and there has been a demand for a tapered container with few of these processing marks.

[0008] On the other hand, according to a spatula draw (spinning process), it is possible to process into a tapered shape in one step, but there are problems that a craftsman is required and the processing speed is slow. Also, the thinner the wall thickness, the higher the skill level required, and the more time it takes for processing.

[0009] In view of the problems exemplified above, the present inventors have repeatedly conducted intensive studies, and have been able to provide a method and a manufacturing apparatus for manufacturing a molded body having excellent aesthetics and a thinner inclined side wall at a higher speed with fewer processing steps using press working, and have reached the present disclosure.

Means for Solving the Problems

[0010] The manufacturing method of a molded body according to an embodiment of the present invention is a method of manufacturing a molded body having a bottom portion and a body portion, an open upper surface, and a shape in which the body portion expands outward as it goes toward the upper surface side, using a drawing member including a pair of male and female dies. The method includes placing a plate-shaped workpiece in the drawing member such that a first surface of the workpiece faces the male die and a second surface opposite to the first surface faces the female die, and performing drawing on the workpiece while applying a pressing force by a fluid in parallel to both the first surface and the second surface.

[0011] Further, a manufacturing apparatus for a molded body according to an embodiment of the present invention includes a male die facing a first surface of a plate-shaped workpiece, a female die facing a second surface opposite to the first surface, a drawing member that performs drawing on the workpiece, and a fluid supply device that supplies fluid to at least one of a first space surrounded by the first surface and the male die and a second space surrounded by the second surface and the female die.

[0012] Furthermore, a molded body according to an embodiment of the present invention has a bottom portion and a body portion, an open upper surface, and includes an inclined side wall in which the body portion expands outward as it goes toward the upper surface side. The inclined side wall has at least two circumferential processing marks having a distance of 15 mm or more from each other.

[0013] Also, a molded body according to an embodiment of the present invention has a bottom portion and a body portion, an open upper surface, and includes an inclined side wall in which the body portion expands outward as it goes toward the upper surface side. The inclined side wall has three or less circumferential processing marks spaced apart from each other.

Advantages of the Invention

[0014] According to the present disclosure, it is possible to provide a method for manufacturing a molded body having an inclined side wall with excellent aesthetics with a small number of processing steps.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Mode for Carrying Out the Invention

[0016] Hereinafter, with appropriate reference to the drawings, the method for manufacturing a molded body, the manufacturing apparatus for a molded body, and the molded body of the present disclosure will be specifically described. Note that the following embodiments show an example of the present invention and explain the content thereof, and do not intentionally limit the present invention. In this specification, "drawing process" shall include "redrawing process".

[0017] <Molded body 1> The molded body 1 of the present embodiment will be described below. As shown in FIG. 1, the molded body 1 of the present embodiment has a container shape provided with a bottom portion 20 at one end of a cylindrical body portion 10 and an opening portion 30 formed at the end opposite to the bottom portion 20. The body portion 10 expands outward from the bottom portion 20 toward the opening portion 30 side. That is, the molded body 1 has a reverse truncated cone shape in which the diameter D of the opening portion 30 is larger than the diameter D of the bottom portion 20. The bottom portion 20 is continuous from the lower end of the body portion 10 toward the opening portion 30. The molded body 1 of the present embodiment can be said to be a so-called tapered container having an inclined side wall in the body portion 10 connecting the opening portion 30 and the bottom portion 20. S than the diameter D of the bottom portion 20 L is large. The bottom portion 20 is continuous from the lower end of the body portion 10 toward the opening portion 30. The molded body 1 of the present embodiment can be said to be a so-called tapered container having an inclined side wall in the body portion 10 connecting the opening portion 30 and the bottom portion 20.

[0018] The inclined side wall in the body portion 10 has a linear and uniform taper shape in cross-section, and the taper angle θ is, for example, 5° to 20°. As long as the molded body 1 of the present embodiment has an inclined side wall in a part of the body portion 10, for example, the lower end (bottom portion 20 side) or the upper end (opening portion 30 side) of the body portion may not have a taper shape. In the present embodiment, the body portion 10 has a cylindrical shape, but it is not limited thereto, and for example, it may have a rectangular tube shape.

[0019] It is preferable that the ratio of the height of the body portion 10 to the diameter length of the bottom portion 20 of the molded body 1 of the present embodiment is a predetermined value of 0.3 or more. Specifically, in the molded body 1 of the present embodiment, the ratio of the height H S to the diameter D of the bottom portion 20 (H / D S ) is 0.3 to 10.0. In particular, it is more preferable that the ratio of the height H S to the diameter D of the bottom portion 20 of the molded body 1 of the present embodiment (H / D S ) is 1.0 to 10.0.

[0020] In the drawing, as an example, a flange 40 is drawn at the peripheral edge of the upper end of the body portion 10, but it is not limited thereto. That is, as long as the body portion 10 includes an inclined side wall, the opening portion 30 may have a known necking shape with a reduced diameter. Further, the opening portion 30 may be formed into a shape (for example, a curled shape) in which a sharp end face does not directly touch the mouth, like a known paper cup. Furthermore, a known lid (not shown) may be attached to the opening portion 30.

[0021] The body portion 10 constitutes the inclined side wall of the molded body 1 and is formed by drawing a known metal plate such as aluminum or steel, which will be described later. The thickness of the body portion 10 has a certain range depending on the application. For example, as an example, it is configured to have a thickness of approximately 0.06 to 1.5 mm. When the molded body 1 is formed through, for example, ironing, the thickness of the thinnest part of the body portion 10 may be thinner than the thickness of the central part of the bottom portion 20, which will be described later. For example, the thickness of the thinnest part of the body portion 10 may be about 0.06 mm to 0.3 mm. The manufacturing method of the molded body 1 will be described later.

[0022] The bottom portion 20 has a horizontal shape in the illustration, but is not limited thereto. That is, the bottom portion 20 may have a dome shape that bulges inside the molded body 1. Also, the bottom portion 20 may have other known shapes, for example, a shape including a grounding rim portion that protrudes outward and a flat central panel inside thereof. The thickness of the bottom portion 20 has a certain range depending on the application. For example, as an example, it is configured to have a thickness of approximately 0.06 mm to 1.0 mm at its central portion. In the present disclosure, even a molded body with a thin wall thickness of about 0.1 mm to 0.3 mm at the central portion of the bottom portion 20 can effectively suppress wrinkles on the inclined side wall.

[0023] In the molded body 1 of the present embodiment, the thickness of the body portion 10 may be configured to be thicker than the thickness of the bottom portion 20. This is because when the molded body 1 is manufactured by drawing, in the body portion 10, a circumferential compressive force accompanying diameter reduction is applied to the workpiece, resulting in an increase in plate thickness. Also, as a pre-process, for example, the thickness of the body portion 10 may be thinned through ironing or the like. In comparison with the original plate thickness (the plate thickness before drawing) of the workpiece W, the thickness of the bottom portion 20 is preferably approximately equal to the original plate thickness, and the thickness of the body portion 10 is preferably about 20 to 150% of the original plate thickness. In this specification, the "workpiece W" refers to the plate of the material before drawing (so-called "blank").

[0024] In this embodiment, the type of material used for the molded body 1 is not particularly limited, and examples thereof include metal materials, paper materials, and the like. As the metal material, known metal plates commonly used for containers, such as aluminum alloy plates and steel plates (e.g., tinplate, etc.), can be used. Further, the metal plate may be appropriately surface-coated, such as having a known film laminated on at least one side, being coated with an organic resin, or having been subjected to chemical conversion treatment, etc., and may also be a clad material obtained by laminating these metal plates.

[0025] When the material used for the molded body 1 is a paper material, known paper materials used for containers can be applied. Examples of the paper material used for the molded body 1 include kraft paper, pulp, cardboard, and the like. Further, the material used for the molded body 1 may be a laminated material having a resin film coated on its surface. Furthermore, the workpiece of this embodiment may be a laminated material including a metal material or a paper material, and in particular, may be a laminated material of a metal material and a paper material.

[0026] In this embodiment, the inclined side wall of the body portion 10 of the molded body 1 may include circumferential processing marks under predetermined conditions. As the predetermined conditions here, at least conditions regarding the number of circumferential processing marks and conditions regarding the interval between the circumferential processing marks can be exemplified. Note that these conditions will be described later.

[0027] Hereinafter, the circumferential processing marks will be described. In this embodiment, the circumferential processing marks are processing marks on the appearance of the material of the molded body 1 (inside or outside of the body portion 10), and are formed along the circumferential direction (the direction around the central axis O of the molded body 1).

[0028] In the body portion 10, the reason for the occurrence of circumferential processing marks is that multiple processes are performed in the manufacturing process to incline the side wall portion. In the side wall portion of the intermediate molded body obtained in each process, an inclined or stepped shoulder is formed. The shoulder is finally corrected to a smooth inclination to obtain an inclined side wall in the body portion 10. However, due to the bending-back deformation occurring in the shoulder during the correction process, circumferential processing marks are generated on the side wall portion in a circumferential manner. Such circumferential processing marks may be visually recognized as fine irregularities on the appearance, which becomes a factor inhibiting the smoothness and aesthetics of the side wall portion. Further, the number of circumferential processing marks is generated according to the number of shoulders receiving the bending-back deformation. That is, not only the number of processes required for forming the inclined side wall, but also when multiple processes are performed within one process, the same number of circumferential processing marks are generated.

[0029] On the other hand, the molded body 1 of the present embodiment has fewer circumferential processing marks included in the inclined side wall compared to a molded body manufactured by a conventional plurality of processes. Further, when a plurality of circumferential processing marks are included in the inclined side wall of the molded body 1, the interval between them is larger compared to a conventional molded body. The reason is that, as will be described in the manufacturing method described later, the inclined side wall can be manufactured with a smaller number of processes.

[0030] Specifically, in the molded body 1 of the present embodiment, the number of circumferential processing marks included in the inclined side wall, which is the body portion 10, is preferably 3 or less (condition regarding the number of circumferential processing marks). Alternatively, when a plurality of circumferential processing marks are included in the inclined side wall, which is the body portion 10, of the molded body 1 of the present embodiment, it is preferable that the respective circumferential processing marks are spaced apart from each other. Further, the interval between a plurality of spaced-apart circumferential processing marks is preferably 15 mm or more (condition regarding the interval of circumferential processing marks).

[0031] Note that the molded body 1 of the present embodiment may have zero circumferential processing marks included in the inclined side wall. That is, in the manufacturing process of the molded body 1, the ratio of the height H to the diameter D of the bottom portion 20 (H / D S ) is relatively small (for example, (H / D S ) S) is less than 1.0), etc., when forming the entire body portion 10 from the plate-shaped workpiece W by only one drawing process, circumferential processing marks may not be formed. The manufacturing method of the molded body 1 will be described later.

[0032] <Manufacturing Apparatus of Molded Body> Next, the manufacturing apparatus 100 of the molded body in the present embodiment will be described with appropriate reference to FIG. 2. Note that FIG. 2 is a schematic cross-sectional view of the manufacturing apparatus 100. The left side of the central axis O in FIG. 2 is a view of the workpiece W being processed, and the right side of the central axis O in FIG. 2 is a view when the display of the workpiece W is omitted.

[0033] The manufacturing apparatus 100 of the molded body in the present embodiment includes a drawing member. The drawing member includes a pair of male dies 200 and female dies 300. With the manufacturing apparatus 100 of the present embodiment, a drawing process can be performed on the workpiece W. More specifically, with the manufacturing apparatus 100 of the present embodiment, a frustum-shaped molded body can be manufactured by drawing. Examples of the frustum-shaped molded body include a molded body having a bottom portion and a body portion and an open upper surface, and further, a molded body having inclined side walls (taper shape) that expand outward as the body portion goes toward the upper surface side. Note that FIG. 2 shows an apparatus that performs molding by lowering the male die 200, but it is not limited thereto, and an apparatus that performs molding by raising the female die 300 may be used, or a manufacturing apparatus that performs drawing molding by reversing the up and down and raising the male die 200 or lowering the female die 300 may also be used.

[0034] In addition, the manufacturing apparatus 100 of the present embodiment may include a blank punching member. For example, a sheet-like material can be punched into a substantially circular shape by the inner peripheral edge of the punching die 600 (female die) and the outer peripheral edge of the die 300 (male die) to obtain a blank for drawing, and the drawing process can be performed using the die 300 as the female die as it is.

[0035] More specifically, the manufacturing apparatus 100 of the present embodiment includes a cylindrical or columnar punch 200 (male mold), a die 300 (female mold) having the same central axis O as the punch 200, an annular wrinkle presser 400 also having the same central axis O as the punch 200, a workpiece W, and a fluid supply device 500 that communicates with a space surrounded by the punch 200 or the die 300 and supplies fluid to the space.

[0036] The punch 200 is disposed to face one surface (the first surface W 1 side) of the plate-shaped workpiece W. As the punch 200, a known metal punch can be applied. The size of the diameter of the tip portion 201 of the punch 200 is not particularly limited and can be appropriately changed according to the inner diameter of the bottom portion of the molded body to be manufactured. Further, the shape of the tip portion 201 of the punch 200 may be a horizontal shape or other known shapes. Since the shape of the cylindrical side surface 203 of the punch 200 does not contact the workpiece W, it is not particularly limited. Specifically, as shown in FIG. 2, the shape of the cylindrical side surface 203 of the punch 200 may be a straight line parallel to the central axis O direction. Although not shown, by making the shape of the cylindrical side surface 203 of the punch 200 a tapered surface that tapers toward the punch tip portion 201, it can be sandwiched between a die described later at the end of molding, and the shape accuracy can be improved, which is more preferable. Further, the tip portion 201 of the punch 200 and the cylindrical side surface 203 are continuous via a punch shoulder radius R p The size of the punch shoulder radius R p is not particularly limited, and the size of the punch shoulder radius in a known cylindrical drawing can be applied. The punch 200 is configured to be movable along the central axis O inside the die 300 and the wrinkle presser 400. Further, the punch 200 is arranged so as to have the same axis as the die 300 and the wrinkle presser 400.

[0037] The die 300 is on the second surface W 1 which is the opposite side to the first surface W of the workpiece W 2It is disposed to face the side of . In other words, the die 300 is disposed on the side opposite to the punch 200 with the workpiece W interposed therebetween. In the present embodiment, the inner side surface 303 of the die hole 301 of the die 300 has a tapered surface that tapers in the extrusion direction from the side of the wrinkle presser 400. That is, the diameter of the die shoulder 305 portion in the die hole 301 is larger than the diameter of the tip portion 201 of the punch 200 described above. Note that the radius R of the die shoulder of the die 300 d is not particularly limited, and the size of the die shoulder radius in a known cylindrical drawing can be applied. With these configurations, during the drawing process, the workpiece W is formed into a molded body having an inclined side wall along the tapered surface (side surface 303) of the die 300. Note that the taper angle θd of the tapered surface (side surface 303) is generally 5° to 20°. Since the tapered surface (side surface 303) of the die 300 is transferred to the inclined side wall of the molded body to be manufactured, the taper angle θd becomes substantially the same as the angle of the inclined side wall of the obtained molded body.

[0038] The die 300 is disposed coaxially with the above-described punch 200 and a wrinkle presser 400 to be described later. The die 300 is configured to be relatively close to or remote from the punch 200 during the drawing process. As the material of the die 300, a known metal die can be applied.

[0039] The wrinkle presser 400 is disposed coaxially with the punch 200, like the die 300. As the wrinkle presser 400, a known donut-shaped member can be applied. The wrinkle presser 400 generates a wrinkle pressing force on the flange portion of the workpiece W between the wrinkle presser 400 and the die 300. The wrinkle presser 400 may be composed of one member or may be composed of a plurality of divided members.

[0040] In the manufacturing apparatus 100 of the present embodiment, the fluid supply apparatus 500 includes a fluid supply apparatus 501 on the punch 200 side and a fluid supply apparatus 503 on the die 300 side. The fluid supply apparatus 501 communicates with the first space Sp shown in FIG. 2. Note that the first space Sp is, as shown in FIG. 2, at least the first surface W of the workpiece W1 is a space surrounded by the punch 200 and the wrinkle press 400. The fluid supply device 501 can supply a fluid such as compressed air to the first space Sp through the supply passage 511. The fluid supplied to the first space Sp presses the first surface W of the workpiece W 1 in the extrusion direction.

[0041] Note that the fluid supplied to the first space Sp is not limited to compressed air, and known fluids such as oil and water used in metal processing and the like can be applied and are appropriately selected according to the required pressure. Further, as the pressure of the fluid supplied to the first space Sp, it is only necessary to be able to suppress the wrinkles on the inclined side wall of the obtained molded body, and it varies depending on the material used for the molded body. As an example, in the case of an aluminum alloy used for a container such as a beverage can, the pressure of the fluid supplied to the first space Sp is preferably 0.4 to 2.0 MPa.

[0042] The fluid supply device 503 communicates with the second space Sd shown in FIG. 2. Note that the second space Sd is a space surrounded by at least the second surface W of the workpiece W 2 and the die 300 as shown in FIG. 2. The fluid supply device 503 can supply a fluid to the second space Sd through the supply passage 531. The fluid supplied to the second space Sd presses the second surface W of the workpiece W 2 in the direction opposite to the extrusion direction.

[0043] Note that the fluid supplied to the second space Sd may be the same as the fluid supplied to the first space Sp or may be a different type of fluid. Further, the pressure of the fluid supplied to the second space Sd is preferably smaller than the pressure of the fluid supplied to the first space Sp. Note that this pressure difference will be described later.

[0044] Thus, in this embodiment, during the drawing process on the workpiece W, both of the processing surfaces (the first surface W 1 and the second surface W 2Metal processing can be performed while applying a pressing force by a fluid in parallel to (0). Further, by applying the pressing force, wrinkles on the inclined side wall of the obtained molded body can be suppressed. This mechanism will be described below.

[0045] In the present disclosure, the "pressing force by a fluid" may also be simply referred to as the "pressing force". Further, the pressing force on the workpiece W is a force equivalent to the internal pressure of the first space Sp or the second space Sd that changes due to the inflow and outflow of the fluid into and out of the first space Sp or the second space Sd and the increase or decrease in the volume of the first space Sp or the second space Sd during the processing, and specifically, it is a force corresponding to hydraulic pressure or air pressure.

[0046] As described above, when manufacturing a molded body having an inclined side wall, even if the punch and the die are provided with tapered surfaces, a punch having a diameter smaller than the diameter of the die shoulder will be used for processing. As shown in FIG. 2, during the processing, a period occurs in which at least a part of both surfaces of the workpiece W is not restrained.

[0047] Wrinkles in drawing are a buckling phenomenon of the material due to the compressive stress accompanying the diameter reduction. Usually, both surfaces of the workpiece W are sandwiched and restrained between the die and the wrinkle presser to suppress buckling. In particular, when the thickness of the workpiece W is thin, such a buckling phenomenon is likely to occur. Further, in the case of a tapered draw where there is a period in which both surfaces of the workpiece W are not restrained, it has been difficult to suppress such a buckling phenomenon conventionally.

[0048] On the other hand, when the manufacturing apparatus of the present embodiment is used, during the period when both surfaces of the workpiece W are not restrained, a pressing force is applied to both surfaces of the workpiece W by the fluid supplied to the first space Sp or the second space Sd. At this time, the workpiece is deformed like bulge processing by the pressing force, and the material is restrained by being pressed against the tapered surface of the die, thereby suppressing wrinkles. The greater the pressing force and the smaller the material rigidity, the greater the deformation amount of the workpiece, resulting in unintended deformation, breakage, etc. Therefore, when a pressing force is applied to one side of the workpiece, it is impossible to apply a large pressing force to a thin metal plate or the like, and it is difficult to suppress wrinkles. By applying a pressing force to both surfaces of the workpiece, the deformation of the workpiece can be suppressed during the period when the workpiece is not restrained, and the workpiece can be pressed against the tapered surface of the die with a sufficient pressing force. Even for materials that were conventionally difficult to suppress wrinkles, it is possible to suppress wrinkles on the inclined sidewalls.

[0049] In addition, in the present embodiment, although the fluid supply device 500 has been described as being provided independently on both the punch 200 side and the die 300 side, it is not limited to this. That is, the fluid supply device 500 may be shared between the first space Sp and the second space Sd. In other words, the fluid supply device 500 may branch into supply paths 511 and 531 to supply fluid to each space, or after directly supplying fluid to the first space Sp, a part of the supplied fluid may be diverted to the second space Sd side. Conversely, the fluid supply device 500 may directly supply fluid to the second space Sd and then divert a part of the supplied fluid to the first space Sp side. By adopting such a configuration, even if the number of fluid supply devices arranged is small, a pressing force can be applied from both sides of the workpiece W.

[0050] With the manufacturing apparatus of the present embodiment configured as described above, for the region where neither surface of the workpiece W contacts either the punch or the die, the deformation of the workpiece by the fluid is suppressed, and the workpiece can be pressed against the tapered surface of the die with a sufficient pressing force to suppress wrinkles. Therefore, even when the thickness of the material of the workpiece W is thin, the generation of wrinkles on the inclined sidewalls can be suppressed.

[0051] Also, according to the manufacturing apparatus of the present embodiment, even when manufacturing a molded body having a depth, an inclined side wall can be molded with a small number of processes. Therefore, it is possible to reduce the number of circumferential processing marks on a deep tapered container, which was conventionally difficult to avoid, or to increase the interval between the circumferential processing marks.

[0052] The manufacturing apparatus 100 of the present embodiment can be suitably applied when manufacturing a frustum of a cone-shaped molded body by drawing. Further, the manufacturing apparatus 100 of the present embodiment is applicable to any of drawing and redrawing.

[0053] Note that the manufacturing apparatus 100 of the present embodiment may include a pressure adjustment mechanism for adjusting the pressing force of the fluid supplied to the first space Sp or the second space Sd. As an example, the pressure adjustment mechanism includes at least one of the above-described fluid supply devices 501 and 503, and by narrowing the space volume of the first space Sp or the second space Sd via the fluid supply device 501 or the fluid supply device 503, the first surface W 1 or the second surface W 2 may be configured to increase the pressing force against.

[0054] Specifically, as shown in FIG. 2, in the manufacturing apparatus 100 of the present embodiment, the fluid supply device 501 on the punch 200 side may have a piston function of moving a distance Kd in the extrusion direction. That is, when a gas as a fluid is accommodated in the first space Sp, when the fluid supply device 501 moves forward by the distance Kd, the space volume of the first space Sp becomes smaller, and the internal pressure of the first space Sp increases. Therefore, the pressing force against the first surface W 1 can be increased.

[0055] In this way, by providing the pressure adjustment mechanism, the pressing force on the workpiece W can be increased by reducing the space volume of the first space Sp or the second space Sd afterwards. Therefore, the arrangement of a gas compressor or the like can be omitted. As the pressure adjustment mechanism, for example, as shown in FIG. 6 or the like, at least one of the punch 200 side and the die 300 side may be provided with pistons 513 and 533 disposed in the first space Sp or the second space Sd and capable of increasing the pressure in the space.

[0056] <Method for manufacturing a molded body> Next, the method for manufacturing a molded body in the present embodiment will be described with reference to FIGS. 3 to 6. The method for manufacturing a molded body in the present embodiment can be realized by the above-described manufacturing apparatus 100. Further, by the manufacturing method of the present embodiment, the above-described molded body 1 can be manufactured.

[0057] The method for manufacturing a molded body in the present embodiment includes at least a step of placing a plate-shaped workpiece W in a drawing member (placement step) and a step of drawing the workpiece W while applying a pressing force by a fluid to the workpiece (drawing step).

[0058] The placement step is a step of placing the plate-shaped workpiece W in the drawing member such that one surface (first surface W 1 ) of the plate-shaped workpiece faces the male mold 200 and the other surface (second surface W 2 ) of the plate-shaped workpiece faces the female mold 300.

[0059] The drawing step is a step of drawing the workpiece W while applying a pressing force by a fluid in parallel to both surfaces (first surface W 1 and second surface W 2 ) of the workpiece W.

[0060] The shape of the workpiece W used in the manufacturing method in the present embodiment can be substantially disc-shaped. However, it is not limited thereto, and the shape of the workpiece W may be a known shape such as a polygon.

[0061] Examples of the material of the workpiece W include metal materials, paper materials, etc. Note that since the materials applicable here are the same as those described for the above-mentioned molded body, detailed description thereof is omitted here.

[0062] Figure 3 is a schematic diagram showing in detail the flow of the manufacturing method in this embodiment. Specifically, FIGS. 3(a) and 3(b) are diagrams showing the placement process, and FIGS. 3(c) and 3(d) are diagrams showing the drawing process.

[0063] Each process will be described in more detail below. Regarding the placement process, as shown in FIG. 3(a), the workpiece W is placed such that one surface (the first surface W 1 side) faces the punch 200 side and the other surface (the second surface W 2 ) faces the die 300 side. Next, fluids are respectively supplied to the first space Sp surrounded by the first surface W 1 and the punch 200, and the second space Sd surrounded by the second surface W 2 and the die 300. Then, pressing forces are applied in parallel to both surfaces of the first surface W 1 and the second surface W 2 of the workpiece W by the supplied fluids (FIG. 3(b)).

[0064] Next, with pressing forces applied in parallel to both surfaces of the first surface W 1 and the second surface W 2 of the workpiece W, the drawing process is started as the drawing process (FIG. 3(c)). Specifically, the punch 200 moves in the extrusion direction to perform drawing on the workpiece W. When the drawing process is completed, a molded body having inclined side walls along the tapered surface of the die 300 is formed as shown in FIG. 3(d). Thereafter, the supply of fluids to the first space Sp and the second space Sd is stopped, and the molded body is taken out.

[0065] According to the manufacturing method of the present embodiment, when the thickness of the workpiece is thin or when manufacturing a tapered container having a depth, even when the inclination angle is large and the drawing clearance is wide, the inclined side wall can be formed with a small number of steps as a whole. Therefore, the number of circumferential processing marks included in the inclined side wall of the obtained molded body 1 can be reduced. Or, when a plurality of circumferential processing marks are included in the inclined side wall of the obtained molded body 1, the interval between them can be increased. In this way, it is possible to manufacture a molded body having an inclined side wall with excellent aesthetics.

[0066] Hereinafter, the step of supplying fluid into the first space Sp and the second space Sd will be described in more detail. The supply of fluid to the first space Sp and the second space Sd may be performed separately as shown in FIG. 4, or may be performed from either one as shown in FIG. 5.

[0067] More specifically, as shown in FIG. 4, fluid can be supplied to the first space Sp and the second space Sd via the supply path 511 and the supply path 531, respectively. In this case, the same fluid or different types of fluid may be supplied to the first space Sp and the second space Sd, respectively.

[0068] Note that the fluid in the first space Sp presses the first surface W of the workpiece W in the pushing direction of the punch 200 with the same pressure magnitude as the pressure of the fluid supplied from the supply path 511 (Pascal's principle). Similarly, the fluid in the second space Sd presses the second surface W of the workpiece W in the direction opposite to the pushing direction with the same pressure magnitude as the pressure of the fluid supplied from the supply path 531. 1 2

[0069] It is more preferable from the viewpoint of the desired wrinkle suppression that the value p1 of the pressure in the first space Sp and the value p2 of the pressure in the second space Sd are adjusted so that p1>p2, at least during the drawing process.

[0070] On the other hand, as shown in FIG. 5, the fluid may be supplied from either the first space Sp or the second space Sd. Specifically, in FIG. 5, a fluid supply passage 531 is formed to communicate with the second space Sd, while a supply passage 511 communicating with the first space Sp is not formed. Further, a gap Ga is formed between the die 300 and the wrinkle presser 400, and the first space Sp and the second space Sd communicate with each other through this gap Ga.

[0071] Therefore, the fluid supplied to the second space Sd through the supply passage 531 wraps around into the first space Sp through the gap Ga, so that the inside of the first space Sp is filled with the same fluid as that supplied to the second space Sd. Also in this case, in the stable state, the first surface W 1 and the second surface W 2 are applied with equal pressing forces.

[0072] Note that the manufacturing method of the present embodiment may further include a step of increasing the pressure in the first space Sp or the second space Sd, that is, the pressing force of the fluid against the first surface or the second surface of the workpiece (pressure increasing step). Specifically, the increase in the pressing force in the pressure increasing step may be a step of narrowing the space volume of the first space or the second space.

[0073] The pressure increasing step will be described with reference to FIG. 6. Specifically, as shown in FIG. 6(a), after gas as a fluid is supplied to each of the first space Sp and the second space Sd, the supply passage is blocked. In this way, the first space Sp and the second space Sd become sealed spaces.

[0074] Next, as shown in FIG. 6(b), the piston 513 and the piston 533 move respectively. Thereby, the space volumes of the first space Sp and the second space Sd are narrowed, and the gas accommodated inside the space is compressed.

[0075] Specifically, as the piston 513 moves in the pushing direction in conjunction with or independently of the lowering of the punch 200, the volume of the first space Sp is narrowed, and the first surface W 1The pressing force applied thereto also increases accordingly. Similarly, as the piston 533 moves to the side opposite to the extrusion direction, the volume of the second space Sd is reduced, and the second surface W 2 The pressing force applied thereto also increases.

[0076] In the manufacturing method of the present embodiment, by including the pressure increasing step, a non-compressible gas can be used as the fluid for applying the pressing force, which is simple.

[0077] Note that the fluid supply or pressure increasing step to the aforementioned first space Sp or second space Sd may be performed in only one of the first space Sp or the second space Sd. That is, fluid is supplied to the first space Sp via the supply path 511 to apply a pressing force to the first surface W 1 and the volume of the second space Sd is reduced by the pressure increasing step to increase the pressing force applied to the second surface W 2 as well. Conversely, a pressure increasing step may be performed in the first space Sp, and fluid may be supplied to the second space Sd via the supply path 531. Further, an air cylinder (not shown) may be installed, and the balance between the increase in the internal pressure and the decrease in the space volume of the first space Sp or the second space Sd may be appropriately changed.

Example

[0078] Examples implemented based on the above-described method are shown. However, the present invention is not limited to the following examples at all.

[0079] (Example 1 and Example 2) An aluminum alloy plate (A3104-H19) with a base plate thickness of 0.27 mm was punched into a circular blank with a diameter of 105 mm, and formed into an inverted frustum shape in one step using a cylindrical drawing punch (outer diameter Φ49 mm) and a drawing die having a tapered surface (shoulder inner diameter Φ58 mm). At this time, using the manufacturing apparatus shown in FIG. 2, from the start to the end of the forming, compressed air at an arbitrary pressure was introduced on the drawing punch side and the drawing die side to perform the forming.

[0080] The obtained molded body had a flange diameter of 90 mm, a height of 19 mm, a taper angle of 16°, and H / D S = 0.38. The presence or absence of wrinkles in the obtained molded body was as shown in Table 1. The appearance photographs were as shown in Figs. 7 and 8, and the body part included inclined side walls. Note that the inclined side walls did not include circumferential processing marks visible from the outside. Also, in Example 1 (Fig. 7), although slight undulations (non-smooth surface properties) were observed on the inclined side walls, longitudinal (height-direction) streak-like wrinkles such as those seen in Comparative Example 1 described later were not included. In Example 2 (Fig. 8), longitudinal (height-direction) streak-like wrinkles or cracks were not included in the inclined side walls.

[0081]

Table 1

[0082] (Comparative Example 1) From the start to the end of molding, molding was performed without introducing fluid from the draw punch side and the draw die side. Otherwise, a frustum-of-a-cone-shaped molded body was obtained in the same manner as in Example 1. The obtained molded body had a flange diameter of 90 mm, a height of 19 mm, and a taper angle of 16°. The appearance photograph of the obtained molded body was as shown in Fig. 9. The inclined side walls did not include circumferential processing marks visible from the outside. However, the inclined side walls included longitudinal (height-direction) streak-like wrinkles.

[0083] (Comparative Examples 2 and 3) From the start to the end of molding, fluid was introduced only from the draw punch side, and molding was performed without introducing fluid from the die side. Otherwise, a frustum-of-a-cone-shaped molded body was obtained in the same manner as in Example 1. The obtained molded body had a flange diameter of 90 mm, a height of 19 mm, and a taper angle of 16°. The inclined side walls did not include circumferential processing marks visible from the outside. In Comparative Example 2, although improvement was observed compared to Comparative Example 1, undulations were seen on the inclined side walls. In Comparative Example 3, the deformation of the blank due to the pressing force was large, and cracks occurred at the punch shoulder, and a molded body could not be obtained.

[0084] As described above, by performing drawing while applying a pressing force by a fluid in parallel to both surfaces of the workpiece, while applying a pressing force sufficient to suppress wrinkles, unintended deformation of the workpiece is suppressed, and it has been shown that a molded body including an inclined side wall having no circumferential processing marks or wrinkles can be obtained.

[0085] The embodiments and examples described above are examples embodying the gist of the present invention, and appropriate modifications may be made without departing from the above gist of the present invention. Furthermore, within the range not departing from the above gist of the present invention, a known structure may be added to the manufacturing method, manufacturing apparatus, and molded body shown in the embodiments.

Industrial Applicability

[0086] The present disclosure can be used for containers capable of storing liquids such as beverages, and is particularly applicable to containers that require excellent aesthetics.

Explanation of Signs

[0087] 1 Molded body 10 Barrel part 20 Bottom part 30 Opening part 40 Flange D S Diameter of the bottom part D L Diameter of the opening part 30 H Height of the barrel part O Central axis 100 Manufacturing apparatus 200 Male mold 300 Die 400 Wrinkles suppressor 500 Fluid supply apparatus

Claims

1. A method for manufacturing a molded body having a bottom and a body, an open upper surface, and a shape in which the body widens outward as it goes toward the upper surface side, using a drawing member including a pair of male and female dies, comprising: a step of placing a plate-shaped workpiece in the drawing member such that a first surface of the workpiece faces the male die and a second surface opposite to the first surface faces the female die; a step of drawing the workpiece while applying a pressing force by a fluid in parallel to both the first surface and the second surface; A method for manufacturing a molded body, characterized by including the above.

2. The method for manufacturing a molded body according to claim 1, wherein the pressing force is applied to both the first surface and the second surface by flowing the fluid into at least one of a first space surrounded by the first surface and the male die and a second space surrounded by the second surface and the female die.

3. The method for manufacturing a molded body according to claim 1 or 2, further comprising a step of increasing the pressing force by narrowing at least one of the first space and the second space. The method for manufacturing a molded body according to claim 1 or 2.

4. When the pressing force of the first space is p1 and the pressing force of the second space is p2, p1 > p2 The method for manufacturing a molded body according to claim 1 or 2, satisfying the above.

5. The method for manufacturing a molded body according to claim 1 or 2, wherein the workpiece is any one of a metal material, a paper material, and a laminated material of a metal material and a paper material. The method for manufacturing a molded body according to claim 1 or 2.

6. A drawing member including a male die facing a first surface of a plate-shaped workpiece and a female die facing a second surface opposite to the first surface, and performing drawing on the workpiece; A fluid supply device for supplying a fluid to at least one of a first space surrounded by the first surface and the male die and a second space surrounded by the second surface and the female die; A manufacturing apparatus for a molded body, comprising the above.

7. The manufacturing apparatus for a molded body according to claim 6, wherein the fluid supply device communicates with either the first space or the second space via a supply path capable of supplying the fluid. The manufacturing apparatus for a molded body according to claim 6.

8. The manufacturing apparatus for a molded body according to claim 6 or 7, further comprising a pressure adjustment mechanism for increasing the pressing force of the fluid flowing into the first space or the second space against the first surface or the second surface. The manufacturing apparatus for a molded body according to claim 6 or 7.

9. Having a bottom and a body, an open upper surface, and including an inclined side wall in which the body widens outward as it goes toward the upper surface side, The molded body, wherein the inclined side wall has at least two circumferential processing marks having an interval of 15 mm or more apart from each other.

10. A molded body having a bottom portion and a body portion, an upper surface thereof being open, and the body portion including an inclined side wall that expands outward as it goes toward the upper surface side, wherein the inclined side wall has three or less circumferential processing marks spaced apart from each other.

11. The diameter length D of the bottom part Ｓ The ratio (H / D Ｓ ) of the height H of the body part to the diameter length D is 0.3 to 10.0 The molded body according to claim 9 or 10.

12. The molded body according to claim 9 or 10, wherein the plate thickness of the bottom portion is 0.1 mm to 0.3 mm.

13. The molded body according to claim 9 or 10, wherein the plate thickness of the thinnest portion of the body portion is 0.06 mm to 0.3 mm.

14. The molded body according to claim 9 or 10, which is made of any one of a metal material, a paper material, and a laminated material of a metal material and a paper material.

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