JPH11267769A - Die and punch for drawing resin coating material, and method of drawing with such die and punch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drawing die for resin coating material, a die capable of drawing without causing a scratch on a resin coat. SOLUTION: In a drawing die 6 consisting of an approach 11, a land 12, and a relief 13, the entrance angle α of the approach 11 is 2-10 deg., the length L of the land 12 is 0.5-1.0 mm, the clearance angle β is 0.1-1.0 deg., the exit side angle γ of the relief 13 is 2-8 deg., the land 12 side of the approach 11 is formed in a circular-arcuate shape with a radius R of 0.05-5 mm and is smoothly connected to the land 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die suitable for ironing a resin-coated material and a method for ironing a resin-coated material using the die.

[0002]

2. Description of the Related Art Among resin-coated food or beverage cans, the tallest cans are prepared by punching a blank from a resin-coated material in which a PET film is coated (adhered) on both sides of an aluminum alloy plate, as shown in FIG. The blank 1 is pressed into a drawing die 2 with a punch 3 and drawn to form a raw can 4. The can body 5 of the raw can 4 is ironed with an ironing die 6 and a punch 7 to manufacture the blank. The series of drawing and ironing are referred to as DI processing. In FIG. 2, reference numeral 8 denotes a can after drawing. The high can is also manufactured by a method of thinning and redrawing while giving a tensile deformation. Also, cans with a low height are manufactured by single or multi-stage drawing. The conventional ironing die is designed for a metal plate that is not coated with a resin, and a high-hardness cemented carbide or the like is used for the die material, and its inner surface shape also has a sharp edge. When the raw can is ironed using a die, there is a problem in that the resin film is scratched. For this reason, an ironing die suitable for a resin coating material has been proposed (Japanese Patent Application Laid-Open No. 9-285827), but it cannot sufficiently prevent abrasion of the resin film. In addition, the method of applying a lubricant to an ironing die in order to prevent abrasion requires cleaning the can after processing, which requires a great deal of cost for managing the cleaning liquid and treating the waste liquid.

[0003]

Therefore, the present inventors have studied a method of ironing a resin coating material that does not cause abrasion on the resin film, and have found that the above-mentioned abrasion can be reduced by improving the structure of the ironing die. After finding out and further researching, the present invention was completed. An object of the present invention is to provide an ironing die for a resin coating material that can be ironed without causing scratches on a resin film, and a method of processing a resin coating material using the die.

[0004]

According to the first aspect of the present invention,
In an ironing die having an inner surface composed of an approach portion, a land portion, and a relief portion, the approach angle α of the approach portion is 2 to 10 °, the length L of the land portion is 0.5 to 1.0 mm,
The relief angle β of the land portion is 0.1 to 1.0 °, the exit angle γ of the relief portion is 2 to 8 °, and the land portion side of the approach portion is formed in an arc shape having a radius (R) of 0.05 to 5 mm. The ironing die for resin coating material is characterized by being smoothly connected to the land.

According to a second aspect of the present invention, there is provided the ironing die for resin coating material according to the first aspect, wherein the inner surface is coated with a surface treating agent having excellent lubricity.

According to a third aspect of the present invention, there is provided an ironing punch for a resin coating material, wherein an outer surface is coated with a surface treating agent having excellent lubricity.

[0007] The invention according to claim 4 is the invention according to claim 1 or 2.
An ironing method for a resin coating material, wherein ironing is performed by using the ironing die described in the above and / or the ironing punch according to claim 3 at an ironing rate of 40 to 60%.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The resin coating material to be processed by the ironing die of the present invention is made of a base metal such as an aluminum alloy (JIS-A5182 alloy plate or the like) plate or a steel plate for a can material having excellent strength and formability. Both surfaces are coated with resin. As the coating resin, polyethylene terephthalate (PET), polypropylene (PP), polyethylene (PE), polyvinyl chloride, or the like is used. Among them,
The polyethylene terephthalate (PET) does not contain chlorine, so there is no risk of polluting the atmosphere at the time of disposal, and the polyethylene terephthalate (PET) has an excellent gas barrier property, so that its contents are well protected and suitable.

Hereinafter, the ironing die of the present invention will be specifically described with reference to the drawings. FIG. 1 is an explanatory longitudinal sectional view showing an example of an ironing die for resin coating material of the present invention. The inner surface of the ironing die 6 approaches the approach portion 11 from the material entry side,
A land portion 12 and a relief portion 13, the approach angle 11 of the approach portion 11 is 2 to 10 °, the length L of the land portion 12 is 0.5 to 1.0 mm, and the clearance angle β of the land portion 12 is 0.1
゜ 1.0 °, the output side angle γ of the relief portion 13 is 2２〜8 °, and the radius (R) of the approach portion 11 on the land 12 side is 0.05.
It is formed in an arc shape of about 5 mm.

In the present invention, the reason why the entry angle α is defined as 2 to 10 ° is that when the entry angle α is less than 2 °, the contact length between the material and the die is long because the inner diameter of the tip of the approach portion is determined. As a result, the frictional force increases, causing cracks (breaks) in the can. Also, when the entry angle α exceeds 10 °, the strain rate locally rises sharply, and the portion is heated by processing to generate resin coating. This is because of the deterioration.

In the present invention, the land portion 12 serves to hold the raw can 4 coaxially with the die 6 and prevent uneven thickness. In the present invention, the reason for defining the length L of the land portion 12 to be 0.5 to 1.0 mm is that if the length L is less than 0.5 mm, concentric holding of the can is insufficient and uneven thickness occurs, and
Is exceeded, the frictional force with the raw can 4 increases, and the can is broken (broken).

The raw can 4 has already been ironed to the thickness of the can at the time of leaving the approach portion 11 of the ironing die 6, and the can is cooled and shrunk when passing through the land portion 12, and this shrinkage is caused. The amount substantially balances the amount of outward elastic deformation of the base metal. However, since the resin film on the can surface has a larger elastic deformation than the base metal, the resin film comes into contact with the inner surface of the land 12 at a high surface pressure, and as a result, the resin film is scratched. The reason why the relief angle β is provided in the land portion 12 in the present invention is to relieve the surface pressure and prevent abrasion. In the present invention, the reason for setting the clearance angle β of the land portion 12 to 0.1 to 1.0 ° is that if the angle is less than 0.1 °, the effect of preventing abrasion is not sufficiently obtained, and if the angle exceeds 1.0 °, the land This is because the concentric holding force of the can at the portion is reduced, the shaft of the can is displaced, and uneven thickness occurs.

In the ironing process, the punch 7 and the die 6 are coaxial until the punch 7 passes through the land portion 12, but after passing through the land portion 12, the axis of the punch 7 may be shifted from the die axis. If the shift occurs, the punch 7 comes into contact with the die 6 when the punch 7 returns to the original position, and is damaged. The axis deviation is a phenomenon caused by the ear 9 (see FIG. 2) caused by the anisotropy of the material (blank). That is, immediately after leaving the land portion 12, the can moves laterally to the lower side of the ear 9,
Accordingly, the axis of the punch 7 is shifted. In the present invention, the exit angle γ of the relief portion 13 of the ironing die 6 is specified to be small (8 ° or less), so that the lower portion of the ear 9 of the can hits the wall surface of the relief portion 13 and the lateral movement of the can 5 is suppressed. Thus, the axial deviation of the punch 7 is prevented. In the present invention, the reason for setting the exit side angle γ to 2 to 8 ° is that if the angle exceeds 8 °, the above-described displacement preventing effect cannot be obtained, and if the angle is less than 2 °, the inner diameter of the rear end of the relief portion 13 becomes smaller. The reason for this is that the die 6 becomes thicker, the land portion 12 becomes substantially longer, the frictional force increases, and the body is broken.

In the present invention, the reason why the land portion 12 side of the approach portion 11 is formed in an arc shape and is smoothly connected to the land portion 12 is that if the land portion 12 side is formed sharply, it is located at the entrance of the land portion 12. This is because the resin film is shaved off and the shaved resin film adheres to the dies, causing contamination and cracking of the can. The radius (R) of the approach portion 11 on the side of the land portion 12 is 0.05 to 5 mm.
The reason for the formation of a circular arc is that if it is less than 0.05 mm, the circular arc becomes steep, and the resin film is scraped off at this portion, and 5 m
If the length exceeds m, the land portion is substantially elongated, the frictional force increases, and the body is broken.

In the present invention, by applying a surface treatment agent having excellent lubricity to a portion of the ironing die in contact with the resin coating material, the occurrence of abrasion of the resin film can be suppressed more reliably. If the surface treatment agent is coated on the outer surface of the punch that is in contact with the resin coating material, a higher effect can be obtained. It is also effective to coat a surface treating agent only on the outer surface of the punch. The coating process of the surface treatment agent is a coating process so that the surface treatment agent is not peeled off on the surface of the die or the punch. Specifically, it is a vapor-phase coating of diamond-like carbon (DLC). The DLC is suitable for ironing a material having a soft surface such as a resin coating material.

In the ironing process of the resin coating material, if the process is performed at a moderately high temperature (high temperature not exceeding the melting point), the resin is uniformly deformed, and a desired surface quality can be obtained. A third aspect of the present invention is a method for processing a can at a moderately high temperature by increasing the processing rate and causing heat to be generated when ironing is performed using the ironing die of the present invention. If the working ratio is less than 40%, the heat generated by the working is insufficient and an appropriate high temperature for uniformly deforming the resin cannot be obtained. If the working ratio exceeds 60%, the resin coating layer or the base metal reaches the working limit and cracks occur. Therefore, the working ratio is defined as 40 to 60%.

[0017]

The present invention will be described below in detail with reference to examples. (Example 1) A JIS-A3004 alloy plate or a JIS-A5182 alloy plate having a thickness of 0.3 mm was punched into a blank, and PET films were formed on both surfaces of the blank by a PET film.
It was adhered to a thickness of 5 mm to obtain a resin coating material. Next, this resin coating material was processed into a can having a capacity of 350 cc by DI processing. The shape of the ironing die and the ironing conditions were variously changed within the specified range of the present invention.

(Comparative Example 1) A can was processed in the same manner as in Example 1 except that the shape of the ironing die and the ironing conditions were out of the range of the present invention.

The breaking ratio of Example 1 and Comparative Example 1 during ironing was examined. The resulting cans were also examined for scratches on the resin film. The number of tests (n) was 100 in each case. Table 1 shows the results.

[0020]

[Table 1] (Note) α: Approach angle of approach part, β: Relief angle of land part, γ: Exit angle of relief part, R: Radius of land side arc-shaped part of approach part, L: Length of land part, can Quality: 極 め て extremely good, ○ good. Fracture rate: The rate at which the metal matrix of the can was broken.

As is clear from Table 1, No. 1 of the present invention example
In all of Nos. To 3, the breaking ratio was 0, and the can was of good quality with no scratches on the surface (resin film). Especially N
o.3 The surface quality of the beverage can was extremely good because DLC was coated on the ironing die. DLC did not adhere to the can. On the other hand, in the die No. 4 of the comparative example, since the radius R of the arc on the land side was small, the resin film was peeled. In No.5, the base metal was cracked because the land was long. No. 6 had uneven thickness because the length L of the land portion was short. In No. 7, scratches occurred because no relief angle was provided in the land. In No. 8, the entrance angle α of the approach portion was large, and the resin film deteriorated. No. 9 had a crack in the resin film due to the large ironing rate. In No. 3 of the first embodiment, the DLC was coated only on the die. However, even if the DLC was coated only on the punch, or both were coated, the same as in the case of No. 3 of the first embodiment. It was confirmed by an experiment conducted separately that the effect or a higher effect was obtained.

[0022]

As described above, the ironing die according to the present invention has an approach angle of the approach portion, a length of the land portion, a relief angle of the land portion, an exit side angle of the relief portion, and a land portion side of the approach portion. Since the shape and the like are properly defined, the can processed using this ironing die has no resin scratches and excellent surface quality. Further, if the die is coated with a surface treatment agent having excellent lubricity, the quality of the resin film is further improved. Using the ironing die,
When ironing is performed at a predetermined processing rate at which an appropriate processing heat is obtained, the quality of the resin film is further improved. Therefore, an industrially remarkable effect is achieved.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an example of an ironing die of the present invention.

FIG. 2 is an explanatory diagram of DI processing of a resin coating material.

[Explanation of symbols]

 Reference Signs List 1 resin-coated blank 2 drawing die 3 drawing punch 4 raw can 5 can body 6 ironing die 7 ironing punch 8 can 9 can's ear 11 approach part 12 land part 13 relief part

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁶ Identification code FI B21D 51/26 B21D 51/26 X

Claims (4)

[Claims] 1. An ironing die having an inner surface including an approach portion, a land portion, and a relief portion, wherein the approach angle α of the approach portion is 2 to 10 ° and the length L of the land portion is 0.5.
1.0 mm, land clearance angle β is 0.1 to 1.0
゜, the outlet side angle γ of the relief portion is 2 to 8 °, and the land portion side of the approach portion is formed in an arc shape having a radius (R) of 0.05 to 5 mm and is smoothly connected to the land portion. Ironing dies for resin coating. 2. The ironing die according to claim 1, wherein the inner surface is coated with a surface treating agent having excellent lubricity. 3. An ironing punch for a resin coating material, wherein an outer surface is coated with a surface treatment agent having excellent lubricity. 4. A resin coating, wherein the ironing process is performed by using the ironing die according to claim 1 or 2 and / or the ironing punch according to claim 3 at an ironing rate of 40 to 60%. Ironing method of wood.