JPH0867992A - Method for working metal - Google Patents

Abstract

PURPOSE: To efficiently form a metallic formed article having intricate ruggednesses on the surface by patterning the metal surface with ruggednesses and then plastic-working the metal. CONSTITUTION: Plural circles are printed on the surface of a disk 1 of superplastic alloy with a resist ink 2. The surface is masked 3, and then a rugged pattern 4 is formed by etching. The disk is set in a die 7 and blow-molded into a specified vessel by utilizing superplastic deformation, and the vessel having clear embossed circles is obtained. This process can be applied to a thin-walled product, and further even a small number of products are economically 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 manufacturing a metal product having a pattern of irregularities on its surface.

[0002]

2. Description of the Related Art A number of proposals and practical applications have been made in the past for a method of forming a pattern such as a pattern or a character on a metal surface by means of unevenness. For example, there is known a method of efficiently producing a striped steel sheet having a non-slip projection on its surface using a roll having a recess.

Further, as a widely used method, there are coining and rolling processing performed on coins. Coining is a method in which a punch in which patterns and letters are irregularly formed is pressed into a flat metal plate and pressed to form a desired pattern. With this method,
The processed metal surface can be not only a flat surface but also a three-dimensional curved surface. The material before processing is not necessarily required to be flat.

On the other hand, the rolling process is a process in which a pattern or a character is engraved on the outer peripheral surface of a disc-shaped metal plate such as a coin, and a work material is placed between two tools having irregularities such as a pattern. It is a processing method of rolling and coining while sandwiching and applying pressure.

The irregularities, patterns, and characters formed by the above-described processing method result in embossing, but they should also be called indentation rather than embossing, and basically metal removal. Is not done.

On the other hand, in the etching method as disclosed in Japanese Patent Laid-Open No. 34167/1992, a protective film is partially applied to the surface of metal by photoresist or silk clean printing, and then the other part is applied. It is a method of melting by etching to form thick and thin portions, and then removing the protective film to obtain a metal product having a pattern of irregularities on the surface.

Since the etching method has a step of placing a resist on a material, it is relatively easy when the target surface is a flat surface. There is no limitation on the size of the product, and it is possible even when the size is considerably large, such as 1 m × 1 m. The main target is thin shape, but the thickness is not limited. of course,
The metal surface having irregularities obtained in these cases is usually flat.

On the other hand, as an etching method for making unevenness on a curved surface, there is a technique disclosed in JP-A-63-121676. In this method, a pattern is screen-printed on a stretchable transparent rubber thin film, and a three-dimensional curved surface coated with a photosensitizer is covered, and exposure, development, etching, and resist stripping are performed.

Further, Japanese Patent Laid-Open No. 26780/1992 discloses a technique in which a resist is applied to a curved surface, printing is performed on the curved surface, exposure, development, etching, and resist stripping are performed to etch the curved surface.

Further, it is often practiced that after applying a pattern by etching, plastic deformation is applied to a portion including an etched portion. In that case, it is natural that the final pattern has a so-called collapsed shape, which is different from the initial pattern.

Therefore, when plastic deformation is applied to a portion including an etched portion, it is desirable that the final pattern after plastic deformation has a desired shape, but such a technique is not disclosed.

[0012]

However, each of the above processing methods has the following problems. First, rolling methods are limited to metals that can withstand rolling. In addition, for example, when applied to steel materials, the deformation resistance of the material is large, so it is necessary to perform at high temperature in order to make deep irregularities. Since there are restrictions on the patterns that come from the processing method, continuous simple patterns are inevitable. In addition, the cost of rolls and the cost of rolling mills are also important, and basically application to products other than mass-produced products is not realistic.

Next, in coining and rolling, a rigid tool having irregularities is used to apply pressure to the material, which requires extremely high processing pressure. for that reason,
This cannot be done if the material is not rigid enough. The size of the product is also limited, and when applied to thin shapes,
In some cases, the molded body itself cannot withstand processing.
Further, since manufacturing a rigid tool requires a great deal of cost and skill, this processing method is also difficult to apply except when the number of manufactured products is large.

Since the etching method has a step of placing a resist on a material, it is relatively easy when the target surface is a flat surface, but is not necessarily suitable when it is a curved surface or the like. For example, when the material has a complicated curved surface such as a vase with a narrow mouth and a bulging bottom, it is difficult to apply not only screen printing but also a method using a photoresist.

The method using a screen-printed rubber capable of etching a curved surface is said to be limited to a surface having a relatively large radius of curvature. Further, the method of screen-printing a resist applied on a curved surface does not show a specific curvature or the like, but it is considered to be possible only under extremely limited conditions.

Of course, there is also a method of applying the resist ink by handwriting, but it goes without saying that mass production is impossible, the efficiency is low, and the cost is extremely high. In the case of forming a simple pattern such as a straight line on a simple shape, for example, a cylindrical material, it is possible to mount the resist mechanically. However, when etching such a non-planar material, the efficiency is low and it is technically difficult as compared with the case of the flat plate material.

As described above, a method for industrially obtaining a metal product having a three-dimensional curved surface having irregularities has not been established. The present inventors have completed the present invention based on the idea that plastic working is performed after etching.

[0018]

According to a first aspect of the present invention, there is provided a metal working method in which a metal pattern is formed on a surface of a metal by etching, and thereafter a plastic deformation is performed to substantially deform the pattern.

Here, giving a substantial deformation to a pattern means the following. That is, by giving deformation, not only the length or interval of the etched lines or the like forming the pattern is changed, but also the deformation of giving the desired length or interval only after the deformation is given. To tell. Therefore, since the pattern to be etched is naturally different from the pattern observed after deformation, it is not possible to decide the pattern to be etched in consideration of the final desired pattern, the deformation characteristics of the metal, and the processing method. Needless to say.

The surface of the metal to be etched may be flat or flat. The surface of the metal after plastic working may be a surface including a three-dimensional curved surface.

The plastic working may be one which causes superplastic deformation of a metal, and a forming method such as a blow molding method or a roll bending method can be used.

Explaining the specific procedure, first, a resist is applied to the metal surface for etching. The method of applying a resist may be a commonly used method and is not particularly limited. For example, a portion which is not etched with a resist ink may be formed by screen printing or the like, and a photoresist may be used. If necessary, a surface not requiring etching may be masked to protect it, and in some cases, a method of etching from one side may be adopted.

Here, the surface of the material metal is not limited to a flat surface or a curved surface having a large radius of curvature. The resist can be placed efficiently, and if the etching is not extremely difficult as compared with a flat material, it is possible to use a material of any shape.

Next, etching is performed. The present invention covers all metals that can be etched. For example,
It can be widely applied to metals such as copper, aluminum, iron, nickel, gold, silver and titanium, and alloys thereof such as stainless steel, brass and white copper.

As the etching method, a conventional and obvious method can be used. Examples of the etching solution include iron, copper, aluminum and their alloys of brass, ferric chloride solution for stainless steel, nitric acid for titanium and titanium alloys, dilute nitric acid for zinc, hydrochloric acid for chromium, Nitric acid can be used for brass.

The conditions such as the etching time are determined by the depth of the unevenness finally required. In this case, it goes without saying that the processing conditions to be performed thereafter must be taken into consideration. In the case of cold forming, the strain amount is about several tens of percent even if it is estimated at the maximum, and it is about 100% at the local level, though it varies depending on the shape of the formed body. For example, even when the depth of the irregularities is about 10 μm, the irregularities that can be recognized after the molding process, and therefore, remain sufficiently as a pattern.

On the other hand, warm and hot forming can give a large deformation as compared with cold forming, and particularly when superplastic deformation is performed, a remarkably high workability can be given. For example, when molding is performed by the superplastic blow molding method, a strain of up to 300% can be applied. In such a case, it is necessary to increase the etching depth, and in the minimum case, about 20 μm is necessary.

When the etching depth is 10 μm or less and the large processing of 300% or more is given, the pattern becomes unclear. However, when such a pattern is intended, the pattern is etched shallowly and large processed. The method is preferred. The depth of etching can be freely changed, but it takes time to perform deep etching,
In many cases, intergranular corrosion occurs and the etched surface becomes rough. But, conversely, it may be preferred.

Next, the resist and masking are removed, and then the metal having a pattern formed by the unevenness is plastically deformed to be processed into a predetermined shape. As a forming method, either bulging forming or deep drawing can be applied depending on the purpose, and it is not particularly limited. Of course, the shape after plastic deformation may be flat.

Metals and alloys having extremely excellent workability are particularly excellent in exhibiting the features of the present invention. A typical example thereof is a superplastic alloy, and examples thereof include iron-based, aluminum-based, titanium-based, zinc-based, copper-based, and nickel-based alloys.

In the case of a molding method using a rigid tool such as a die or a punch, caution is required because the possibility that the patterned surface rubs against the tool and the pattern after molding is crushed increases. In the case of processing in which the pattern surface is on the punch side, damage to the pattern surface can be reduced. A method using a lubricant such as lubricating oil is also effective in carrying out this method. In some cases, the recesses formed by etching also serve as oil reservoirs. Due to the large number of oil reservoirs, it is possible to greatly reduce the frictional force during processing and reduce the damage to the pattern surface.

However, the present invention exerts the most excellent effect when the surface to be etched is arranged on the pressurizing medium side and blow molding is performed. In this case, since the etching surface does not contact the tool until the end of molding, no flaws are formed and a clear pattern is obtained.

It is of course possible to make the pressure side a convex surface. In this case, wrinkles may occur, but they are sometimes preferred. Further, in the blow molding method, the material is pressed against the tool by the molding pressure, but it is also possible to transfer the material to the outer surface of the product as a step between the thick portion and the thin portion. Of course, it is also possible to make unevenness on both sides by the unevenness made on one surface.

In the roll-forming method, the roll surface touching the patterned surface is made of natural rubber, butadiene and S.
Synthetic rubber such as BR rubber and various resins such as polyethylene, polyamide, polyurethane and polyester may be used.

When bending is performed so that the etching surface becomes the outer surface of the cylinder, it is necessary to use two elastic rolls as the etching surface, but the etching surface becomes the inner surface of the cylinder. In the case of performing the bending process as described above, only one roll that comes into contact with the etching surface may be the elastic body-coated roll.

[0036]

According to the present invention, a flat metal surface is etched to form a pattern of concavities and convexities, and then plastic working is performed. Since etching is performed on a flat metal surface, it is possible to easily and efficiently form a complicated pattern, and the etching depth can be easily controlled. In particular, the etching depth differs depending on the degree of plastic deformation and the expected final pattern depth, but these requirements can be easily met.

Further, since a plastic deformation is given thereafter, a predetermined pattern can be formed on the three-dimensional curved surface portion of the final product. In particular, it has been difficult in the prior art to form a complicated pattern on a curved surface having a small radius of curvature, but by etching a pattern on the surface of the metal and then applying plastic deformation utilizing superplastic deformation. It is a great advantage that a predetermined pattern can be obtained even on such a curved surface portion having a small radius of curvature.

If blow molding is used as the plastic working method, superplastic deformation can be easily utilized.

In the roll forming method, the roll surface that comes into contact with the patterned surface is made of synthetic rubber or resin, so that the plastic working can be carried out without any flaws on the patterned surface.

[0040]

【Example】

[Example 1] As shown in FIG. 1 (a), a diameter of φ4 mm and a thick line are formed on the surface of a disc 1 of Ti-6% Al-4% V-based alloy of 0.9 mmt and φ120 mm which is a superplastic alloy. A plurality of 0.44 mm thick circles were printed by a screen printing method using resist ink 2 to form a portion to be etched and a portion not to be etched.

After masking 3 on the back surface as shown in FIG. 1 (b), etching was performed for 60 seconds as shown in FIG. 1 (c). The etching solution is 3% hydrofluoric acid-10% nitric acid. The height of the circle is 39μ due to etching.
A pattern of m was obtained. After that, the resist ink and the masking were removed as shown in FIG.

This disc was set in a mold as shown in FIG. 1 (e) and blow molding was carried out by utilizing superplastic deformation.
As a condition for causing superplastic deformation, a molding temperature of 900
C., molding pressure 8 atm, molding time 4 hours were selected and blow molding was performed with the etching surface facing inward.
It was molded into a predetermined container as shown in. The workability of the most distorted portion was 202% by this working, but the height of the circle was 21 μm and remained on the inner surface of the molded body, and a container having a clear embossed circle was obtained.

[Embodiment 2] Using the same material as in Embodiment 1,
After a pattern was formed by the same process, the pattern surface 6 was placed on the punch 8 side as shown in FIG. 2 and molded into a cup shape. Since the pattern surface 6 is on the punch 8 side, damage to the pattern surface could be minimized. The molding temperature is 900 ° C. and the molding time is 2 hours. This condition is also a condition that causes superplastic deformation. The machining rate of the most distorted part due to this machining was 223%,
The height of the circle was at least 19 μm and remained on the inner surface of the molded body, and a container having a clear embossed circle was obtained.

[Example 3] 1.5 mmt of Al-6% Mg-
A 0.4% Zr-based alloy plate was used to apply a photoresist, and then a mask having a wavy pattern was overlaid and exposed. After that, development is performed, and after removing the unnecessary portion of the photoresist, etching is performed to form a pattern with unevenness of 0.4 mm on the surface. Then, as shown in FIG. 3, the etched surface is turned inside by the blow molding method. Then, a hemispherical blow molding was performed at 450 ° C. to manufacture a container in which irregularities on the inner surface were raised on the outer surface.

[Example 4] Using a 1.5 mmt SUS316 stainless steel thin plate, a photoresist was applied, and subsequently, a mask having a pattern was overlaid, exposed, and developed to remove an unnecessary portion of the photoresist, and etching was performed. The work was repeated twice to form a geometric pattern with a maximum depth of 0.4 mm. After that, as shown in FIG. 4, the roll surface that touches the patterned surface is roll-molded with the surface that is etched using a roll covered with SBR rubber as the outside, and the unevenness is raised to the outer surface with a diameter of 70 mm. A cylinder having a height of 300 mm was prepared, and then seam welding and bottom plate welding were performed to prepare a vase.

[0046]

EFFECTS OF THE INVENTION According to the present invention, it is possible to efficiently obtain a metal molded product having complicated irregularities on the surface. In particular, 1) It can be applied to products with thin wall thickness as compared with the conventional mechanical method. 2) It can be applied to large products. 3) It can be economically manufactured even if the production cost is low and the number of manufactured products is small. It has advantages such as Further, as compared with the curved surface etching method, 4) it is possible to manufacture a product having a surface with a small radius of curvature having complicated unevenness. It has many advantages over other methods, such as having advantages.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of the present invention using a blow molding method.

FIG. 2 is an explanatory view of the present invention using a punch forming method.

FIG. 3 is an explanatory diagram of the present invention in which a pattern formed by unevenness on one surface is transferred to the other surface by a blow molding method.

FIG. 4 is an explanatory view of the present invention using a roll forming method.

[Explanation of symbols]

 1 Material Plate 2 Resist Ink Forming Pattern 3 Masking 4 Concavo-convex by Etching 5 Gas for Blow Molding 6 Concavo-convex Surface Subjected to Plastic Processing 7 Molds / Tools 8 Punches 9 Rolls 9a Rolls with Elastic Surface

Claims (1)

[Claims] 1. A method for processing a metal, which comprises forming a pattern of irregularities on a surface of a metal by etching and then performing a plastic working for substantially deforming the pattern.