JPH08300056A - Forming method of aluminum foil and the like - Google Patents

Abstract

PURPOSE: To efficiently produce a deep drawing formed body having no wrinkle and height larger than diameter by bulging with air pressure after a blank of aluminum foil, etc., is subjected to deep drawing with using a die and punch. CONSTITUTION: While a blank 1 of aluminum foil, etc., is held between a die of deep drawing and a blank holder, deep drawing is executed by elevating a punch. The space between a die 11 equipped with a tool 15 for product take out and a metal mold 12 equipped with a pump 13 for compressed air/an air introducing port is evacuated with mounting a packing 14 and then the blank 1 subjected to deep drawing is set, the blank 1 is bulged at one breath with introducing compressed air. Use of high pressure compressed air makes forming speed larger and eliminates contamination of formed body, in the case of the blank 1 heated to 40-100 deg.C, the forming pressure is lowered and the elongation is increased as well. By this method, the wrinkle at side face generated at deep drawing is eliminated and deep drawing formed body having the height higher relative to the diameter can be produced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a thin aluminum foil or the like which is liable to cause wrinkles, and in particular, it has a high forming speed for a container having a tapered shape having a deep height with respect to the caliber.
The present invention relates to an effective molding method that does not require steps such as washing and drying.

[0002]

2. Description of the Related Art In recent years, containers made by deep-drawing aluminum foil have been used for food, cosmetics, electronic parts, office work by taking advantage of their low cost, corrosion resistance, hygiene, beauty, lightness, simplicity, and light-shielding properties. It is widely used as a storage container or packaging material for items, stationery and toiletries. In particular, the range of its use is expanding as a simple container for pastes and solids as a food and drink container. In addition to demanding cost reduction and material thinning, these containers are required to be easily stacked and automatically supplied because most of them are automatically filled with contents in an automatic packaging line. Often. For this reason, many of them are cup-shaped with a wider mouth than the bottom, and because it is required to have a large internal volume, a container with a deeper bottom than the caliber is required, such as thin aluminum foil. Will be. In order to respond to such demands, thin aluminum foil etc. are formed by a forming method such as deep drawing, but when forming a container with a bottom deeper than the caliber, it is vertical on the side wall surface of the container. The formation of crocodile was inevitable.

In order to avoid the formation of wrinkles, the punch for deep drawing is changed to an elastic body (rubber) to prevent a gap from being formed between the punch of the die and the die of the mold, and the aluminum foil or the like is pressed against the die strongly. There is a method of suppressing wrinkles. However, this method has a problem in that the elastic body of the punch is largely consumed and has no durability. Further, there is a proposal of a method for preventing the formation of wrinkles on the side wall by performing deep-drawing to a halfway and then forming by extrusion. According to this method, the wrinkles generated during deep drawing can be stretched to some extent by bulging to prevent wrinkles from occurring to some extent, but during bulging, the part where the punch contacts the aluminum foil (punch shoulder). Part) is preferentially deformed, so that it is easily broken, and the aluminum foil or the like is not stretched uniformly, so that the effect of suppressing the generation of wrinkles is small. Furthermore, it is difficult to form a container having a large container depth with respect to the diameter by using only the overhang forming, which is said to cause less wrinkling, in the same way as in the deep forming where the wrinkle suppressing pressure is increased. It is desired to establish a method for manufacturing a molded container having a large depth from the side wall and no wrinkles on the side wall surface.

[0004]

DISCLOSURE OF THE INVENTION According to the present invention, a wrinkle-prone aluminum foil or the like is used as a raw material, the molding speed is high, and steps such as washing and drying are not required after molding, and there is no wrinkle on the side wall surface. The aim is to establish a manufacturing method for containers with a deeper bottom than the diameter.

[0005]

According to the present invention, a blank such as an aluminum foil is formed by using a die and a punch in the molding of a foil such as aluminum or a laminate of aluminum and the like in which a foil such as aluminum and a thermoplastic resin film are laminated. A method for forming an aluminum foil or the like which is subjected to deep drawing and then bulging using air pressure, and a method for forming the aluminum foil or the like described above which is performed by heating the forming temperature in deep drawing and bulging to 40 to 100 ° C. The above objective was achieved by development. The aluminum foil or the like used in the present invention is aluminum or an aluminum alloy, but is not limited to, preferably a pure aluminum system, an aluminum-manganese alloy system (3000).
System), aluminum-magnesium alloy system (5000
20 to 200 μm thick, or a resin-coated aluminum foil or the like, or a thermoplastic resin film having a thickness of 80 to 500 μm on one or both sides of the aluminum foil or the like. A laminated foil or the like.

The thermoplastic resin film can be used as long as it can be formed into a film, but a film of polyethylene terephthalate or a polyolefin such as polypropylene or polyethylene is particularly preferable in terms of molding, product performance, price and availability. . As these laminates, those obtained by subjecting an extrusion coating or a foil such as aluminum to a primer treatment and then dry laminating a thermoplastic resin film can be suitably used. Such a thermoplastic resin film may be stretched or unstretched, and is laminated on one side or both sides of a foil such as aluminum. The total thickness of these aluminum foils is
Although it does not vary depending on the purpose of use of the target molded body (container), the size of the shape, etc., the overall thickness is generally 10 to 120 μm when the foil such as aluminum is used alone, and 30 to when the laminate foil is used. The thickness of the foil such as 300 μm and aluminum is about 10 to 80% of the total thickness. It is possible to use a thicker aluminum foil or the like by selecting the conditions, but it is merely excessive quality, resulting in an increase in cost. On the other hand, depending on the size of the molded product, if the thickness of these is too thin, the shape retention of the molded product will be reduced, so it is preferable to avoid it.

According to the present invention, such a blank of aluminum foil or the like is first formed as a first stage by a conventional deep drawing machine until a slight wrinkle occurs. In this case, even if some wrinkles are generated, it is possible to eliminate the wrinkles by the second-stage bulge molding, so it is not so strict.
Next, this blank is molded by a bulge molding method using air pressure. The air pressure in this case is not constant depending on the thickness of the aluminum foil or the like, the cross-sectional area of the molded product, the molding degree, etc., but is generally about ² to 20 kgf / cm ² , preferably 4 to 10 kgf / cm ² . Since the normal bulge molding method uses a liquid as the pressure fluid, the molding speed is low, and cleaning and drying after molding are required, whereas the method of the present invention uses high-pressure air, so the molding speed is high. Not only is it possible to increase the size, but there is no stain on the molded product and there is no need for drying, so post-processing can be greatly simplified.

It should be noted that, although it varies depending on the kind of resin laminated at the time of this molding, the blank is 40 to 100.
When the molding is performed by heating to 50 ° C., preferably 50 to 80 ° C., the molding pressure is reduced, and the elongation of the foil such as aluminum is improved, so that the effect of suppressing wrinkles is further exerted. It is possible to form a container with a depth that cannot be obtained by itself.

The present invention will be described in detail with reference to the drawings. FIG. 1 is a cross section of a deep drawing apparatus, in which a blank 1 such as an aluminum foil is sandwiched between a die 2 of a deep drawing die and a wrinkle restrainer 3. Subsequently, the punch 4 is raised to perform deep drawing, but the degree of forming at this time may be such that the side wall surface of the blank has some vertical wrinkles as long as the blank is not broken. This vertical wrinkle can be eliminated during the second stage bulge forming. After performing the deep drawing in this manner, as shown in FIG. 2, between the die 11 equipped with the tool 15 for taking out the product, and the mold 12 equipped with the pump 13 for the thick compressed air and the air introduction port. After sandwiching the packing 14 to make it airtight, the blank 1 formed by deep drawing is set, compressed air is introduced and the blank is expanded at a stretch to perform molding. At this time, the wrinkles on the side surface of the container generated during deep drawing are completely stretched and eliminated, and a wrinkle-free container can be manufactured. The first-stage deep-drawing molding and the second-stage bulge molding may be performed by separate devices, but may be performed by one device in two steps.

[0010]

In conventional deep drawing using a punch and a die, no matter how the punch material is changed,
It was unavoidable that the punch shoulder had the largest place where the pulling pressure was applied in the blank, and the space between the corner of the die and the punch shoulder was unavoidable. Therefore, the stretched blank is likely to have wrinkles on the side surface of the container, and only a shallow container can be formed in order to obtain a wrinkle-free container.

On the other hand, in the bulge forming, since the blank is stretch-formed by using the pressure fluid, the blank is stretched because the pressure-applied portion of the blank is uniformly pressed anywhere between the die 11 and the die 12. However, the range between them is uniform, and since a solid such as a punch is not used, friction and the like do not occur between the molds, and uniform overhang molding is performed. Therefore, the wrinkles generated in the first stage deep drawing are also stretched. As a result, it becomes possible to manufacture a deep-formed product having a deeper depth than in the case of simple deep drawing, a combination of deep drawing and extension forming, or extension forming. In addition, despite using a combination of deep drawing and bulge forming, since the bulge forming method using compressed air is adopted, washing and drying steps are not required and high speed forming is possible. , A highly productive molding method was developed.

[0012]

【Example】

(Sample 1) Dry-laminated aluminum laminate foil consisting of 30 μm thick unstretched polypropylene film / 40 μm thick 1N30 (O material) aluminum foil / 200 μm thick unstretched polypropylene film having a diameter of 1
A blank having a diameter of 10 mm was prepared.

(Sample 2) A dry-laminated aluminum laminate foil comprising a 30 μm thick unstretched polypropylene film / 70 μm thick 1N30 (O material) aluminum foil / 200 μm thick unstretched polypropylene film was punched to a diameter of 110 mmφ to prepare a blank. did.

A blank of Samples 1 and 2 was punched with a taper angle of 8 ° and a diameter of 50 mmφ (12.5 mmR).
Deep drawing was performed using a die (51.5 mmφ, 2R) at a blank heating temperature of 60 ° C. Also, in the above molding, take out the blank when a few wrinkles occur,
This was subjected to bulge molding at an air pressure of 6 kgf / cm ² (gauge pressure). The results of this molding are shown in Table 1.

[0015]

[Table 1]

[0016]

Industrial Applicability According to the present invention, an aluminum foil or the like is first deep-drawn to the extent that a small amount of wrinkles are formed, and then bulge forming is performed by using air pressure, so that a shape having no wrinkles and a height higher than the diameter is formed. It succeeded in efficiently producing the deep-drawn molded article at a low cost. These containers are made of aluminum or a resin film coated with aluminum and have excellent corrosion resistance, hygiene, and airtightness. Therefore, food and drink packaging materials that use automatic packaging lines, electronic component packaging materials, and office supplies packaging materials. It can be used as a general packaging material such as wood. Further, since it also has a light-shielding property, it can be widely used as a packaging material for chemical products such as cosmetics, pharmaceuticals, and photographic chemicals.

[Brief description of drawings]

FIG. 1 is a sectional view of a first stage deep drawing.

FIG. 2 is a sectional view of the second stage bulge forming.

[Explanation of symbols]

 1 Blank 2 Deep drawing die 3 Wrinkle suppressor 4 Punch 11 Bulge forming die 12 Mold 13 Air pump 14 Packing 15 Product removal device

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B21D 51/18 B21D 51/18 D // B29C 51/08 9268-4F B29C 51/08 (72) Inventor Takashi Atsumi, Showa Aluminum Co., Ltd., 6-224, Kaiyama-cho, Sakai City, Osaka Prefecture

Claims (2)

[Claims] 1. A foil of aluminum or aluminum alloy (hereinafter referred to as aluminum or the like), or a laminate of aluminum or the like laminated with a foil of aluminum or the like and a thermoplastic resin film (both a foil of aluminum or the like and a laminate of aluminum or the like). In the process of molding aluminum foil, etc.), a blank such as aluminum foil is deep-drawn using a die and a punch, and then bulge molding is performed using air pressure. 2. The method for forming an aluminum foil or the like according to claim 1, which is performed by heating the forming temperature in deep drawing and bulge forming to 40 to 100 ° C.