JPH06305009A - Deep drawing-stretching molding method - Google Patents

Abstract

PURPOSE:To reduce the amount of a material lamrnating foil and to obtain a molded form having a large inner volume even with the same bore by one pressing by deep drawing molding the foil laminated with synthetic resin by using a press having a variable blank holder, and then stretching to mold it. CONSTITUTION:A material in which a thermoplastic resin film is laminated at least on one surface of aluminum or aluminum foil is used. A blank 4 is set to a press, a die 3 is raised in a state that a previous material is deep drawn while pressing a flange of the blank 4 by a deep drawing molding pressure of 100-500kg between a variable blank holder 1 and a die 2, and a deep drawing molding is conducted at a limiting drawing ratio of about 60-90%. Then, a mold clamping pressure between the holder 1 and the die 2 is raised to a stretching molding pressure of 1000-3000kg in a state that the flange is not completely drawn, and then stretching molded to less than limiting value. Thus, in the case of molded forms of the same bore, deeper molded form can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deep drawing method which is excellent in formability of a laminate (hereinafter referred to as a laminated foil) in which a thermoplastic resin film is laminated on an aluminum or aluminum alloy foil, and particularly a limiting drawing ratio (LDR). The present invention relates to a deep-drawing method having a large inner volume and excellent moldability even with the same diameter.

[0002]

2. Description of the Related Art In recent years, a laminated foil has been deep-drawn into a cup shape, which is inexpensive, corrosion resistant, hygienic, beautiful, lightweight,
It is widely used as a container or packaging material for foods, medicines, office supplies, stationery, toiletries, etc. due to its simplicity. In particular, as a food container, it is widely used as a simple container such as paste or solid.

Such a molded body is generally molded by deep drawing with a press machine. Although the laminate foil is excellent in malleability, the LDR is usually around 2 and is large at the same diameter. Although it is required to manufacture a molded product having an inner volume, this improvement is not easy because cost and simplicity of manufacturing process are required.

That is, when the material is directly deep-drawn by LDR or more, the laminate foil is broken at the punch shoulder portion or the side wall portion at the time of molding, and a normal molded product cannot be obtained.

For this reason, usually, a step of forming a cup shape having a diameter larger than a target diameter by an initial drawing process and then performing a plurality of drawing processes to form a small-diameter cup shape having a predetermined size is adopted.

However, in the above-mentioned conventional deep drawing, it is necessary to use molds having different diameters every time drawing is performed a plurality of times, and a plurality of presses are used when forming in a continuous line. Equipment must be installed. Further, when the number of pressing devices is smaller than the number of molds, there is a problem that inconveniences in terms of equipment and processes cannot be avoided, such as a mold changing operation is required at the time of molding.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above problems and produces a molded article having a large inner volume (deep molding height) even if the bore diameter is the same in one press working. The objective is to develop a molding method that has excellent moldability, uses a small amount of laminate foil, and reduces costs.

[0008]

According to the present invention, a press forming machine equipped with a variable wrinkle retainer is used, and a material of a laminate obtained by laminating a thermoplastic resin film on at least one surface of an aluminum or aluminum alloy foil is first subjected to a flange portion. The above object was achieved by developing a deep-drawing method for an aluminum foil laminate, which is characterized by performing deep-drawing in which the material is drawn, and then performing extension forming in which the flange portion is not drawn.

In the present invention, the aluminum or aluminum alloy is typically a pure aluminum type, an aluminum-manganese alloy (3000 type), an aluminum-magnesium alloy (5000 type) or the like, but other alloy type. But there is an effect.

The thermoplastic resin may be used if it can be formed into a film, but a film made of polyethylene terephthalate or a polyolefin such as polypropylene or polyethylene is particularly preferable from the viewpoints of performance, price and availability.

It is more effective that these films are biaxially stretched. An unstretched film of polypropylene, polyethylene or the like or a laminate laminated by extrusion lamination is ineffective. The biaxially stretched film or aluminum foil is preferably a laminated foil obtained by subjecting it to a primer treatment with a silicon coupling agent, a titanium coupling agent or the like and then dry laminating it.

The synthetic resin film is laminated on at least one side, preferably both sides, of an aluminum foil.
Depending on the application, a laminated foil such as a five-layer lamination having three layers of synthetic resin film and aluminum foil inserted between the layers may be used. The molded product obtained from this laminated foil has a high level of gas barrier property, moisture-proof property, and excellent light-shielding property. Can be used as packaging material.

The total thickness of these laminated foils is not constant depending on the specifications of the target molded product, but generally the total thickness is 80 to 500 μm, and the thickness occupied by aluminum is 20 to 80 of them. %. It is possible to use a thicker laminated foil by selecting the conditions, but only excessive quality leads to an increase in cost. On the other hand, a laminated foil having a thickness of 80 μm or less has a problem in shape retention of the obtained molded product.

The pressing device used for deep drawing-overhang forming of the present invention is equipped with a variable wrinkle presser 1, and the mold clamping pressure can be changed on the die surface during pressing.
First, the blank 4 is set in a press machine, and the die 3 is pushed up while the material of the blank 4 is pressed between the variable wrinkle presser 1 and the die 2 with a deep drawing pressure of 100 to 500 kg. , LDR 60 ~
After performing a deep drawing operation about 90%, the mold clamping pressure between the variable wrinkle presser 1 and the die 2 is increased to a molding pressure of 1,000 to 3,000 kg with the flange part not being fully drawn, and then the limit value is reached. Overhang less than.

By doing so, a deeper molded product can be obtained when the molded product has the same diameter. Further, when manufacturing a molded product having the same diameter and the same depth, a small blank may be required.

[0016]

It has been found that the present invention makes it possible to obtain a deeper molded product even if the molded product has the same diameter by using the laminated foil in which the aluminum foil and the thermoplastic synthetic resin are laminated, rather than the aluminum foil alone. It is based on the finding that the depth can be further increased by first performing deep drawing and then performing stretch forming in pressing.

Further, when a molded product having the same diameter and the same depth is manufactured, it is possible to use a material having a smaller blank diameter by adopting the method of the present invention.

Although the reason has not been completely analyzed,
Perhaps the thin part of the aluminum foil of the deep-drawn intermediate product undergoes work hardening more strongly than the thick part, but the part of the thin wall where the hardening is weak is stretched by overhang forming and the whole is stretched uniformly. It is presumed that it enabled larger processing as a whole.

[0019]

【Example】

(Example 1) A press equipped with a punch type 33 mmφ and a variable wrinkle retainer using a laminate foil having a blank diameter of 62 mmφ, which is obtained by dry laminating a biaxially stretched film on both sides of a 100 μm thick 1N30 aluminum foil using a urethane adhesive. Using a machine, deep drawing was performed up to a forming depth of 10 mm, and thereafter stretch forming was performed, and the minimum depth at which the laminate foil was broken at the punch shoulder portion or the side wall portion was determined. The results are shown in Table 1.

[0020]

[Table 1] PET: Biaxially stretched polyethylene terephthalate film (25 μm) PP: Unstretched polypropylene film (50 μm)

(Example 2) Using the same material and the same apparatus as in Example 1, when deep drawing was carried out to a depth of 8 mm and then stretch forming was carried out to a depth of 10 mm, the flange width after molding was 4. The blank diameter required when 5 mm was taken was determined. The results are shown in Table 2.

[0022]

[Table 2]

[0023]

EFFECTS OF THE INVENTION For forming a large-capacity container having the same diameter, conventionally, the deep drawing for this purpose requires a plurality of pressing operations while changing the die to avoid breakage of the punch shoulder or side wall. It was normal to do. The present invention uses a press device equipped with a variable wrinkle retainer, first performs deep drawing under normal conditions, and then increases the pressure of the variable wrinkle retainer to perform stretch forming in a state where the flange portion is not narrowed down, thereby forming a single stroke. In the case of forming a molded body having the same diameter and the same depth by continuously molding with, and by doing so, it has succeeded in reducing the original blank diameter. This has enabled a significant cost reduction.

[Brief description of drawings]

FIG. 1 shows a state of a first stage deep drawing.

FIG. 2 shows a second stage of overhang molding.

[Explanation of symbols]

 1 Variable wrinkle presser 2 Die 3 Punch part 3'Punch part 4 Blank A Deep drawing pressure B Overhang forming pressure

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masanori Takeuchi, Showa Aluminum Co., Ltd.

Claims (2)

[Claims] 1. A deep-drawing method in which a material of a flange portion is first squeezed by using a press-forming machine equipped with a variable wrinkle retainer to laminate a thermoplastic resin film laminated on at least one surface of an aluminum or aluminum alloy foil. After that, a deep drawing-expanding method for an aluminum foil laminate, which is characterized in that the flange part is stretched without being narrowed. 2. The total thickness of the material of the laminate is from 80 to
The deep drawing-projection forming method according to claim 1, wherein the thickness is 500 μm and the thickness of the aluminum or aluminum alloy foil is 20 to 80% of the whole.