JP2001286941A - Manufacturing method of aluminum container with glossy side face - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method to finish an outer side face of an aluminum container to a glossy face with press-drawing only without increasing a working cost so as to solve the problem that the outer side face of the aluminum container is not finished to a glossy face in a conventional press drawing method and a process to grind a container outer face is required to finish a glossy face resulting in increasing a working cost. SOLUTION: A clearance between a die and a core is set to >=40% to <=80% for a thickness of an aluminum plate before press working, press drawing is conducted under the condition that a plate thickness decreasing rate of before/ after press working is >=18% to <=60%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an aluminum container such as an inner pot of an electric rice cooker, and for manufacturing an aluminum container having a glossy side surface by pressing.

[0002]

2. Description of the Related Art When deep-drawing an aluminum container such as an inner pot of a conventional electric rice cooker, usually the deep-drawing pressing is performed by a single-stage press. And the outer surface of the container was completely dull. In addition, when processing is performed so that the reduction rate of the thickness of the aluminum container side surface is 15% or more, there is a problem that the material enters the mold clearance, that is, breaks without entering the mold.

Also, Japanese Patent Application Laid-Open No. 5-84524 discloses that the thickness of a side surface of an aluminum container is reduced to 40% or more and less than 50% by pressing, but the present invention relates to a beer container and the like. In the case of a thin plate having a thickness of 0.3 mm, press working is performed in a state where the clearance between the die and the core is larger than the plate thickness, and a glossy outer surface cannot be obtained by this method.

Further, as a press drawing method, there is a spatula drawing method in addition to a normal deep drawing method. In this processing method, a reduction in sheet thickness can be made 15% or more. It does not have a certain exterior. Therefore,
As a conventional surface finish, a method of obtaining gloss by polishing the outer surface of the container, or a method of external coating or coloring alumite has been adopted, but all have a problem that processing costs are high.

[0005]

In the conventional press-drawing method, the outer surface of the aluminum container cannot be finished to a glossy surface. If a method of polishing the outer surface of the container to finish the glossy surface is adopted, the processing cost is increased. There was a problem that was high.

[0006]

According to the present invention, the clearance between the die and the core is set to be not less than 40% and not more than 80% with respect to the thickness of the aluminum plate before the press working, and the sheet thickness reduction rate before and after the press working is 18%. The present invention relates to a method for producing a side glossy aluminum container, which comprises performing press-drawing so as to have a percentage of 60% or less.

More preferably, the work hardening index of the aluminum plate is 0.22 or more, the elongation is 20% or more, and the tensile strength is 100 N / mm ² or more.
More preferably, the work hardening index of the aluminum plate is 0.5.
23 or more, elongation of 27% or more, tensile strength of 10
0 N / mm ² or more. The number of press drawing steps is preferably two or more and four or less from a normal one-step press. When the number of working steps is increased from the viewpoint of press drawing workability, the degree of work hardening of the aluminum plate is increased, so that workability is deteriorated, so that breakage or cracking is likely to occur. Therefore, it is desirable that the number of processing steps be four or less. It should be noted that the number of working steps does not include the forming step (dimensioning).

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below. In order to make the outer surface of the aluminum container glossy by press drawing, the clearance between the die of the press die and the core is set to 4 mm of the thickness of the aluminum plate.
It is necessary to control it to be 0% or more and 80% or less. Further, it is more preferable to control it to be 50% or more and 75% or less. The reason for this is that by reducing the thickness of the aluminum plate while applying an ironing force to the surface of the aluminum plate during press drawing, the surface is smoothed and gloss can be obtained.

The thickness reduction rate of the aluminum plate by the press drawing is required to be 18% or more and 60% or less with respect to the thickness of the aluminum plate before the pressing.
Further, the reduction rate of the aluminum plate thickness is 30% or more and 55% or more.
% Is more preferable. Further, the number of processing steps needs to be determined in consideration of workability, and is preferably two or three steps.

Regarding the aluminum material to be used, the work hardening index is 0.23 or more in consideration of press workability.
Elongation of 27% or more and tensile strength of 100 N / mm ²
Those described above are preferable, and specifically, JIS 3003 of an aluminum alloy is preferable.

[0011]

EXAMPLES The present invention will be specifically described with reference to examples.

Embodiment A As a material, thicknesses 2.0, 3.0, 5..
JIS3003,30 of 0, 6.0mm, diameter 390φ
An aluminum plate of a temper O material of type 04 was used. These plates are N
Electroetching was performed in a H ₄ Cl aqueous solution with an amount of electricity of 20 coulombs / cm ² , fine irregularities were formed on the surface, and a fluororesin dispersion was applied and calcined to obtain a coated aluminum plate.

The coated aluminum plate and the uncoated plate were press-drawn by individual dies having clearances of 0.6 to 5.0 mm to obtain containers. The molding process was performed in three steps, and each was processed to have the following shapes. First stage inner diameter 215 mm Container depth 134 mm Second stage inner diameter 215 mm Container depth 142 mm Third stage inner diameter 215 mm Container depth 155 mm

The presence or absence of gloss of these containers was visually judged according to the following criteria. ○ The outline of the object appears and the surface is glossy. △ The surface has no gloss partly. × The outline of the object is blurred, and the surface is not glossy. Or those that cannot be machined due to cracks. The thickness reduction rate of the aluminum plate was calculated from the following equation by measuring a measurement sample cut out from the side of the container with a micrometer. Plate thickness reduction rate (%) = {(base plate thickness of aluminum plate)-(plate thickness of glossy part (or pertinent part) of container)} / (base plate thickness of aluminum) x
Table 1 and Table 2 show the results.

[0014]

[Table 1]

[0015]

[Table 2]

[0016]

Example B As a material, an aluminum plate having a thickness of 4.0, 5.0 mm and a diameter of 390φ, one kind of JIS 1000 series, two kinds of 3000 series and one kind of 5000 series was used. Refining is all O materials. These plates were subjected to electrolytic etching in an aqueous solution of NH ₄ Cl with an amount of electricity of 20 coulombs / cm 2 to form fine irregularities on the surface, and a fluororesin dispersion was applied to the surface and baked to obtain a coated aluminum plate. The coated aluminum plate and the uncoated plate were press-drawn by a die having a clearance of 2.9 mm to obtain a pot. The molding process was performed in three steps, and each was processed to have the following shapes. First stage inner diameter 215 mm Container depth 134 mm Second stage inner diameter 215 mm Container depth 142 mm Third stage inner diameter 215 mm Container depth 155 mm The glossiness of these containers and the reduction rate of the aluminum plate thickness are the same as in Example A. It was measured. The work hardening index of the aluminum plate was measured according to JISZ2253. The elongation and tensile strength of the aluminum plate were measured according to JISZ2201 and JISZ2241. Table 3 shows the results.

[0017]

[Table 3]

Regarding the presence or absence of the coating, the same results were obtained in all cases, and a container having a glossy outer surface could be obtained with each aluminum material. The meaning of the symbol of "workability" in Table 3 is described below. ◎ No cracks are generated by press molding, and almost all scratches are caused on the outer surface of the pot due to press molding, which requires correction. do not do. Δ: Scratches requiring correction may occur, and defects such as cracks may occur during press molding.

[0019]

According to the present invention, it is possible to manufacture an aluminum container having a glossy outer surface without increasing the processing cost.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Soji Nishikawa 950 Noda, Oji, Kumatori-cho, Sennan-gun, Osaka Sumitomo Electric Fine Polymer Co., Ltd. Sumitomo Electric Fine Polymer Co., Ltd.

Claims (4)

[Claims] 1. The clearance between a die and a core is 40% or more and 80% of the thickness of an aluminum plate before press working.
The thickness reduction rate before and after press working should be 18% or more and 6
A method for producing a side glossy aluminum container, comprising press-drawing to 0% or less. 2. The work hardening index of an aluminum plate is 0.2.
2 or more, elongation 20% or more, tensile strength 100
The method for producing a side glossy aluminum container according to claim 1, wherein the N / mm ² or more is used. 3. The work hardening index of an aluminum plate is 0.2.
3 or more, elongation 27% or more, tensile strength 100
^{3. The} method for producing a side glossy aluminum container according to claim ^{2, wherein the} N / mm ^{2 is not} less than N / mm ² . 4. The method for producing a side gloss aluminum container according to claim 1, wherein the number of press drawing steps is 2 or more and 4 or less.