JPH02274332A - Manufacture of can - Google Patents

Abstract

PURPOSE:To save can stock by drawing a disk blanked from a sheet stock into a cup-shaped can, ironing it into a large diameter part and a small diameter part having a step, pushing and reverse-drawing the bottom part with a blank holder and, further, drawing in an opening. CONSTITUTION:The sheet stock such as A1, etc., is blanked on a disk, the blanked disk 1 is drawn in a cup-shaped can 2. The cup-shaped can 2 is drawn and ironed by a large diameter part X and a die ring 4 of an ironing punch 3 having a step 3a and drawn by a small diameter part Y and the die ring 4. The bottom part 5a of this can body 5 is pressed by a blank holder 6, the bottom part 5a is pressed by a reverse drawing punch 7 into the inside of a die ring 8 for reverse drawing. Further, a necking stage is carried out to draw in the opening of the can. Consequently, since the seamed part does not exist, contents do not leak, axial buckling strength is improved and the can stock can be saved.

Description

DETAILED DESCRIPTION OF THE INVENTION ■Field of Industrial Application This invention relates to a method for manufacturing a can in which an outer cylinder and an inner cylinder are integrally formed. To provide an economical method for manufacturing cans that does not cause leakage, is resistant to axial loads (buckling loads), and saves can materials.

■Prior Art Conventionally, coffee, sake, and the like are often sold after being heated to an appropriate temperature in vending machines to make them suitable for drinking.

However, it has not been possible to heat food and drink immediately in places such as mountain climbing or camping sites. Therefore, a can with a heating element was developed that can instantly heat the contents inside the container by utilizing the reaction heat generated by a chemical reaction. This heating can is composed of an outer cylinder for holding contents such as coffee or sake, and an inner cylinder for storing a heating element. Furthermore, conventional cans have been proposed in which the space of one can is divided into two and each space stores different contents. Examples of cans used for these purposes include those shown in FIG. 7. In FIG. 7, 50 is an outer cylinder, and this outer cylinder 50 is made by rolling an aluminum plate or a steel plate into a cylindrical shape and welding the ends. Moreover, when the outer cylinder 50 is a composite can body,
It is made by forming a composite material made of layers of paper, aluminum foil, synthetic resin film, etc. into a cylindrical shape. 51 is an inner cylinder, and this inner cylinder 51 is manufactured in a separate process from that of the outer cylinder 50.

The inner cylinder 51 is manufactured by punching a metal plate such as aluminum or steel into a disk shape, and then drawing it into a cup shape. These outer cylinder 50 and inner cylinder 51
Is this the edge 51a of the inner cylinder 51?

It is attached within the outer cylinder 50 by being tightened around the edge 50a of the outer cylinder 50.

■Problems to be solved by the invention However, conventionally, such cans have an outer cylinder 50 and an inner cylinder 5.
1 and 2 are made in separate processes, and these are separately wrapped and tightened, so there is a problem in that the manufacturing process requires a lot of effort. Moreover, when the contents are filled into the city at a filling factory after being tightened in this manner, there is a drawback that the contents leak to the outside due to poor tightening.

The present invention has been made in view of these conventional problems, and an object of the present invention is to provide a method for manufacturing cans that does not require any effort during the manufacturing process and is free from the risk of leakage of contents.

■Means for solving the problem In order to achieve this objective, this invention involves a process of punching out a plate material such as aluminum into a disc shape (punching process), and drawing the punched disc 1 into a cup-shaped can 2. A process of processing (cupping process) and a process of drawing and ironing the cup-shaped can 2 with the large diameter part (X) of the ironing punch 3 having a step 3a and the die ring 4 (I! Two ironing process) ), and the small diameter part (Y) and the die ring 4 undergo a drawing process (drawing process), and then the bottom part 5a of the can body 5 is pressed with a wrinkle presser 6 and a reverse drawing punch 7 is used. This is characterized by a step of pushing the bottom portion 5a inside the die ring 8 and performing a reverse drawing process (reverse drawing process), and further a necking process of narrowing the opening of the can.

■Examples and effects Next, the present invention will be explained based on the drawings.

FIG. 1 is a perspective view showing a disc 1 made by punching a plate material such as aluminum using a cupping press machine in the punching process.0 As the material of the disc 1, a metal plate such as aluminum or steel is used. Ru.

FIG. 2 is a sectional view of a cup-shaped city 2 formed by drawing the punched disk 1 using a cupping press machine. Since this cup-shaped can 2 is simply drawn, its body and bottom are formed to have the same thickness as the original disc 1.

FIG. 3 is a sectional view showing the cup-shaped can 2 formed in FIG. 2 being drawn and ironed.

That is, an ironing punch 3 having a step 3a composed of a large diameter part (X) and a small diameter part (Y) is slid from above onto the inner surface of the can body 5, and is drawn and ironed between it and the die ring 4. The process of forming the can body 5 by processing and drawing is shown. A major feature of this can manufacturing method is that a cup-shaped can 2 is processed using an ironing punch 3 having a step 3a. As the die ring 4, a die ring conventionally used for drawing and ironing is used. In this step, drawing and ironing is performed between the large diameter portion (X) and the die ring 4, so that the body portion of the can body 5 that comes into contact with the large diameter portion (X) is formed to be thin.

On the other hand, only the drawing process is performed between the small diameter part (Y) and the die ring 4, so this small diameter part (Y) and the die ring 4
Only drawing is performed between the two. Therefore, the portion of the can body 5 that contacts the small diameter portion (Y) is formed thick. Note that by adjusting the diameter of the small diameter portion (Y), a slight drawing and ironing process may be performed at the same time between the die ring 4 and the die ring 4.

The can body 5 that has been subjected to the drawing and ironing process described above undergoes a trimming process in which the ends of the can body 5 are trimmed in order to adjust the height dimension of the can body 5 in the next process. The can undergoes a cleaning process to clean the inside and outside surfaces. Furthermore, the can body 5 undergoes an inner surface painting process for the purpose of protecting the inner surface. Note that the trimming process, cleaning process, printing process, and inner surface coating process may be performed after the reverse drawing process, and are not limited to being performed after the drawing and ironing process and the drawing process.

FIG. 4 is a sectional view showing a process of reverse drawing the can body 5 formed in FIG. 3 after undergoing various processes such as a trimming process and a cleaning process.

In this step, while pressing the bottom part a of the can body 5 with a wrinkle presser 6, the bottom part 5a is pushed into the inside of the die ring 8 with a reverse drawing punch 7, and reverse drawing processing is performed. In this step, it is also possible to improve the wrinkle suppressing effect by dividing the wrinkle presser 6 to press the bottom portion 5a as necessary.

FIG. 5 is a sectional view of the desired can obtained after the reverse drawing process, in which the inner cylinder 10 is integrally formed inside the outer cylinder 9. The wall thickness of the can has dimensions a, b, and c, and the wall thickness at the part where the buckling load acts (m part) is made thicker so that it can withstand the desired buckling load. The part (1 part) that is less affected by bending loads is made thinner to save can material. For example, in a can with a diameter of 66, a=0
゜43mm, b=0.38+yun--0,43nu
When a 21st generation can with n and C=0° was made and its buckling strength was measured, it was approximately 150 kg. Similarly, diameter 66n
Can with uniform wall thickness (m = 0.21 mm shown in Figure 5)
) was measured, and the buckling strength was 80 kg ~
It weighed 90 kg. This is considered to be because the buckling strength was improved by increasing the thickness of the m section as shown in FIG.

After the reverse drawing process, a necking process is started in which the opening of the can is narrowed, as shown in FIG. The necking process is performed by a necking machine, and at the same time, it is also possible to perform a step process on the can bottom 9a of the outer cylinder 9 to form a raised bottom 9b in the can holder of the necking machine.

■Effects As explained above, according to this invention, it is no longer necessary to go through the time-consuming process of making the outer cylinder and the inner cylinder in separate processes, and then assembling and tightening them separately, as in the past. The manufacturing process is simplified. In addition, since the can manufactured by the can manufacturing process according to the present invention does not have a seamed portion between the outer cylinder and the inner cylinder, the contents do not leak, and the buckling strength in the axial direction is improved. It is possible to save can material.

[Brief explanation of drawings]

Figures 1 to 6 show an embodiment of the manufacturing method according to the present invention. Figure 1 is a perspective view of a disc cut in the punching process, and Figure 2 is a drawing process in the cupping process. Figure 3 is a cross-sectional view showing the ironing punch, die ring, and can body with steps in the drawing and ironing process, and Figure 4 is the reverse drawing in the reverse drawing process. A cross-sectional view showing punching, tiling, wrinkle pressing, and the can body. Figure 5 is a cross-sectional view of a can that has been necked after reverse drawing. Figure 6 is a cross-sectional view of a can that has been necked after reverse drawing.
FIG. 7 is a cross-sectional view showing a can according to an embodiment of the pond, in which the bottom part is stepped at the same time as the mounting process, and FIG. 7 is a cross-sectional view showing a conventional can. ... Disk, 2 ... Cup-shaped can ... Ironing punch, 3a ... Step, 8
...Die ring, 5.Can body a...bottom, 6..Wrinkle suppressor...reverse drawing punch, X...large diameter section...small diameter section application People Takeuchi Press Kogyo Co., Ltd. Figure 3

Claims (1)

[Claims] (a) A process of punching a plate material such as aluminum into a disc shape (
(b) drawing the punched disc into a cup-shaped can (cupping process); (c) drawing the large diameter part of the ironing punch with steps into the cup-shaped can and die-ring (d) Next, the bottom of the can body is pressed with a wrinkle presser. While pressing, the bottom part is pushed into the inside of the die ring with a reverse drawing punch to apply a reverse drawing process (reverse drawing process); (e) Furthermore, a necking process is performed to narrow the opening of the can. Manufacturing method for cans