Method for manufacturing patterned metal member

Abstract

A method for manufacturing a patterned metal member according to one embodiment of the present disclosure comprises: a step of disposing a sheet material (20), in which a pattern (21) is depicted on a surface thereof, along an inner surface of a mold (10); and a step of casting a metal member by pouring molten metal into the mold (10). In the casting step, the pattern (21) is transferred onto the surface of the metal member.

Description

Method for manufacturing a metal member with a design

[0001] The present disclosure relates to a method for manufacturing a patterned metal member.

[0002] Patent Document 1 discloses a method for producing a metal plate onto which a design is thermally transferred by overlapping a metal plate having an ink-receiving layer formed thereon with transfer paper having a printed design, and heating the resulting sheet while applying pressure.

[0003] Japanese Patent Application Laid-Open No. 2006-069410

[0004] The method disclosed in Patent Document 1 required a process of forming an ink-receiving layer on a metal plate and a process of thermally transferring a design printed on transfer paper by applying pressure and heat, making the manufacturing process complicated.

[0005] The present disclosure has been made in consideration of the above circumstances, and provides a method for manufacturing a patterned metal member that can more easily manufacture a patterned metal member.

[0006] A method for manufacturing a metal part with a design according to one embodiment of the present disclosure includes the steps of: arranging a sheet material having a design on its surface along the inner surface of a mold; and casting a metal part by pouring molten metal into the mold; wherein the design is transferred to the surface of the metal part during the casting step.

[0007] In a method for manufacturing a patterned metal component according to one aspect of the present disclosure, a sheet material with a pattern drawn on its surface is placed along the inner surface of a mold, and molten metal is poured into the mold to cast the metal component. During the casting process, the pattern is thermally transferred from the paper to the surface of the metal component after the molten metal has solidified. In other words, the pattern can be thermally transferred from the paper to the surface of the metal component simply by casting, making it easier to manufacture the patterned metal component.

[0008] The sheet material may be paper, and the temperature of the molten metal poured into the mold may be 370° C. or less. Furthermore, the temperature of the molten metal poured into the mold may be 350° C. or less. With a simple configuration, a clear pattern can be transferred onto the surface of a metal member.

[0009] The molten metal may be a metal containing tin as a main component. Furthermore, the molten metal may be pure tin having a purity of 99% by mass or more, and the purity of the pure tin may be 99.9% by mass or more. With this configuration, the pattern transferred to the surface of the metal member can be made clear.

[0010] The paper may be processed paper. With this configuration, the pattern transferred to the surface of the metal member can be made clear.

[0011] The metal member may be plate-shaped, and in the disposing step, the sheet material may be disposed so as to stand along the inner surface of the mold, and in the casting step, the metal member may be cast so as to stand. Here, in the casting step, the temperature of the molten metal poured into the mold may be lowered as the thickness of the metal member increases.

[0012] The mold may comprise a pair of mating dies that form a pair of main surfaces of the metal member, and a formwork that is sandwiched between the pair of mating dies and forms the outer edge of the metal member, and in the casting process, the sheet material may be sandwiched between one of the pair of mating dies and the formwork, and the molten metal may be poured through an opening provided at the top of the formwork.

[0013] One of the pair of molds on which the sheet material is placed may be made of metal, and the other of the pair of molds may be made of non-metal. By making one of the molds on which the sheet material is placed made of metal, heat removal from the sheet material that comes into contact with the molten metal can be promoted, and deterioration of the sheet material before the pattern is transferred can be suppressed. By making the other mold made of non-metal, heat removal from the molten metal can be suppressed, and the flow of the molten metal in the mold can be promoted.

[0014] The mold may be made of paper. By using a mold made of paper, which is easy to manufacture, it is easy to handle small quantities of a wide variety of products.

[0015] The method may further include a step of cleaning the surface of the metal member onto which the design has been transferred, and a step of applying a clear coat to the cleaned surface of the metal member, which can protect the surface onto which the design has been transferred and make the transferred design clearer.

[0016] Before pouring the molten metal into the mold, a piece of paper may be placed on the molten metal to stir the molten metal, thereby making it possible to clearly transfer the design onto the surface of the metal member.

[0017] The paper placed on the molten metal may be oil-absorbent paper, which allows the pattern to be transferred to the surface of the metal member more clearly.

[0018] The present disclosure provides a method for manufacturing a patterned metal member that allows for easier manufacturing of a patterned metal member.

[0019] 10 is a flowchart showing a method for manufacturing a patterned metal member according to a first embodiment. FIG. 11 is a perspective view showing an example of a casting apparatus used in the method for manufacturing a patterned metal member according to the first embodiment. FIG. 12 is a cross-sectional view showing an example of a casting apparatus used in the method for manufacturing a patterned metal member according to the first embodiment. FIG. 13 is a cross-sectional view showing an example of a casting apparatus used in the method for manufacturing a patterned metal member according to the first embodiment. FIG. 14 is a macrophotograph showing an example of a metal member manufactured by the method for manufacturing a patterned metal member according to the first embodiment. FIG. 15 is an optical microscope photograph comparing the changes in the surface of paper with a black and white print before and after casting. FIG. 16 is an optical microscope photograph comparing the surfaces of the patterned portion and plain portion of a metal member to which a black and white printed design has been transferred. FIG. 17 is a macrophotograph comparing color designs transferred to the surfaces of metal members with different tin purities. FIG. 18 is a macrophotograph comparing the raw materials and molten metal surfaces of 99.9% mass tin purity and 99.99% mass tin purity. FIG. 19 is a flowchart showing a method for manufacturing a patterned metal member according to a second embodiment. FIG. 19 is a macrophotograph showing the melting process in step ST2a shown in FIG. This is a macrophotograph comparing the color patterns transferred to the surface of a metal member with and without oil absorbent paper on the surface of the hot water.

[0020] Hereinafter, specific embodiments of the present disclosure will be described in detail with reference to the drawings. However, the present disclosure is not limited to the following embodiments. In addition, the following description and drawings have been simplified appropriately for clarity of explanation.

[0021] (First embodiment) <Method for manufacturing a patterned metal member> First, a method for manufacturing a patterned metal member according to a first embodiment will be described with reference to Figs. 1 to 4. Fig. 1 is a flowchart showing a method for manufacturing a patterned metal member according to the first embodiment. Fig. 2 is a perspective view showing an example of a casting device used in the method for manufacturing a patterned metal member according to the first embodiment. Figs. 3 and 4 are cross-sectional views showing an example of a casting device used in the method for manufacturing a patterned metal member according to the first embodiment. The left side of Fig. 3 is a cross-sectional view corresponding to the perspective view of Fig. 2.

[0022] It should be noted that the right-handed XYZ Cartesian coordinate system shown in Figures 2 to 4 is for the sake of convenience in explaining the positional relationships of the components. In Figures 2 to 4, the positive direction of the Z axis is vertically upward, and the XY plane is the horizontal plane, which is common to all the figures.

[0023] The metal constituting the patterned metal member to which this embodiment is applicable is, for example, a low-melting-point metal having a melting point equal to or lower than the melting point of tin (232°C). The low-melting-point metal is, for example, a metal containing tin as a main component, such as pure tin or solder. In the case of pure tin, the tin purity is, for example, 99% by mass or more. Furthermore, as will be described in detail later, by increasing the tin purity to 99.9% by mass or more, or even 99.99% by mass or more, the pattern transferred to the surface of the metal member made of pure tin can be made clearer.

[0024] The uses of the patterned metal member to which this embodiment can be applied are not limited in any way, and include, for example, decorative items, tableware, daily necessities, automobile-related accessories, automobile parts, etc. Examples of tableware include trays, plates, coasters, etc.

[0025] First, as shown in Fig. 1, paper with a printed design is placed along the inner surface of the mold (step ST1). Step ST1 will now be described in more detail with reference to Figs. 2 and 3. As shown on the right side of Fig. 3, the illustrated casting apparatus includes a mold 10, which includes mating molds 11 and 12 and a formwork 13.

[0026] In step ST1, as shown in Figures 2 and 3, paper 20 printed with a design 21 is arranged so as to stand along the inner wall of one of the mating molds 11. More specifically, first, as shown on the left side of Figures 2 and 3, paper 20 is sandwiched between one of the mating molds 11 and the formwork 13. Next, as shown on the right side of Figure 3, the formwork 13 is sandwiched between one of the mating molds 11 and the other mating mold 12. As shown in Figure 2, paper 20 is arranged so as to stand along the inner wall of one of the mating molds 11 so that the printed surface of the paper 20 (the surface on which the design 21 is printed) faces the formwork 13. Paper 20 is an example of a sheet material, and a sheet material made of, for example, resin may be used instead of paper.

[0027] Here, the design 21 printed on the paper 20 is not limited in any way, but may be, for example, an image captured by a camera, i.e., a photograph, and may include letters, numbers, and other symbols. It should be noted that, while the design 21 shown in Fig. 2 is a schematic representation of a mountain and a crescent moon, it is not limited in any way. The color of the design 21 may be black and white or color, as long as it can be printed on the paper 20.

[0028] The paper 20 is not particularly limited, but if the design 21 is a photograph, the design 21 transferred to the surface of the metal member can be made clearer by using processed paper such as glossy paper, coated paper, or matte paper. Of these, glossy paper for photographs is preferable. However, unprocessed paper such as plain paper, recycled paper, or high-quality paper may also be used as the paper 20. The thickness of the paper 20 is, for example, 0.2 mm or less.

[0029] The printer that prints the design 21 on the paper 20 is not particularly limited, and may be, for example, an inkjet printer that uses ink or a laser printer that uses toner. The design 21 does not need to be printed, but may be drawn with a pen or the like. In other words, the design 21 only needs to be drawn on the surface of a sheet material such as paper.

[0030] Next, as shown in Fig. 1, a metal member is cast by pouring molten metal (molten metal) into the mold 10 (step ST2). More specifically, as shown on the left side of Fig. 4, the molten metal is poured through an opening 13a provided in the upper part of a formwork 13 sandwiched between a pair of mating dies 11 and 12, to cast the metal member shown on the right side of Fig. 4. In step ST2, a design 21 is thermally transferred from paper 20 onto the surface of the metal member where the molten metal has solidified.

[0031] As will be described in detail later, the temperature of the molten metal poured into the mold 10 (pouring temperature) is, for example, 370°C or lower. If the temperature exceeds 370°C, it becomes difficult to thermally transfer the pattern 21 clearly onto the surface of the metal member. It is presumed that by setting the pouring temperature to 370°C or lower, the pattern 21 can be thermally transferred onto the surface of the metal member without deteriorating the paper 20 and the pattern 21, i.e., the ink or toner.

[0032] Next, as shown in Fig. 1, the surface of the metal member onto which the design 21 has been transferred is washed (step ST3). First, as shown on the right side of Fig. 4, the metal member is removed from the mold 10. If the paper 20 is, for example, glossy photographic paper, the surface of the metal member onto which the design 21 has been transferred will also be transferred with the coating agent of the paper 20 along with the design 21, i.e., ink or toner, and therefore the surface is washed to remove these. More specifically, the surface of the metal member is washed with water using, for example, a melamine sponge.

[0033] Finally, as shown in Figure 1, the surface of the cleaned metal member, i.e., the surface onto which the design 21 has been transferred, is clear coated (step ST4). The clear coating protects the surface onto which the design 21 has been transferred and also makes the transferred design 21 more visible. Here, the clear coating includes all coating processes using transparent resins. Note that steps ST3 and ST4 are not essential in the manufacturing method of the patterned metal member according to this embodiment.

[0034] As described above, in the method for manufacturing a patterned metal member according to this embodiment, paper 20 with a printed design 21 is placed along the inner surface of mold 10 (step ST1), and molten metal is poured into mold 10 to cast the metal member (step ST2). At this time, design 21 is thermally transferred from paper 20 to the surface of the metal member where the molten metal has solidified. In this way, in the method for manufacturing a patterned metal member according to this embodiment, design 21 can be thermally transferred from paper 20 to the surface of the metal member by simply casting a low-melting-point metal, and patterned metal members can be manufactured more easily than the method disclosed in, for example, Patent Document 1.

[0035] <Configuration of Casting Apparatus> Here, the casting apparatus shown in Figures 2 to 4 will be described. The metal member cast by this casting apparatus is a plate-shaped member. For example, as shown on the right side of Figure 4, a pair of mating dies 11, 12 respectively form a pair of main surfaces of the metal member to be cast. The pair of mating dies 11, 12 shown in Figures 2 to 4 are both plate-shaped members. The form 13 is a frame body that is sandwiched between the pair of mating dies 11, 12 and forms the outer edge of the metal member to be cast. As shown in Figure 2, the illustrated form 13 is a plate-shaped frame body, and an opening 13a for pouring molten metal is provided at the top of the form 13.

[0036] One of the molds 11, where the paper 20 is arranged along the inner wall, is made of a metal such as aluminum. This promotes heat removal from the paper 20 that comes into contact with the molten metal, preventing the paper 20 from deteriorating before the pattern 21 is transferred. The other mold 12 is made of a non-metallic material such as wood or ceramics. This prevents heat removal from the molten metal, promoting the flow of the molten metal within the mold 10. Note that cloth may be provided on one or both of the inner walls of the molds 11 and 12.

[0037] The form 13 may be made of metal or non-metal. From the viewpoint of durability, form 13 made of metal such as aluminum or ceramics may be used. On the other hand, from the viewpoint of handling small-lot, high-mix production, form 13 made of paper, which is easy to manufacture, may be used.

[0038] 2 to 4, the pair of mating dies 11, 12 and the formwork 13 are shown standing vertically (in the Z-axis direction), but they may also be tilted from the vertical. The casting apparatus shown in FIGS. 2 to 4 is merely an example, and the casting apparatus is not particularly limited. For example, a simpler casting apparatus may be used in which a formwork 13 having a greater thickness (height) is placed on one of the mating dies 11 arranged horizontally, and molten metal is poured into the formwork 13.

[0039] <Effect of Pouring Temperature> Next, the effect of the pouring temperature on the transfer state of the pattern will be described. Using the casting apparatus shown in Figures 2 to 4, the effect of the pouring temperature of pure tin on the transfer state of the pattern 21 was investigated. Pure tin with a purity of 99.99% by mass (melting point 232°C) was used, and the pouring temperature was changed from 240°C to 370°C in 10°C intervals to investigate the transfer state of the pattern 21 when printed in black and white on plain paper (unprocessed paper) and in color on glossy photographic paper (processed paper). The thickness of the metal component to be cast (i.e., the thickness of the formwork 13) was set to two types: 1.0 mm and 1.5 mm.

[0040] Table 1 summarizes the results of the investigation into the transfer state under various conditions. As shown in Table 1, for the design 21 printed on untreated paper, the transfer state was good for both 1.0 mm and 1.5 mm thick metal members when the pouring temperature was 350°C or less. On the other hand, when the pouring temperature was 360°C or higher, the burnt color of the paper 20 was transferred, so the transfer state was judged to be acceptable.

[0041] As shown in Table 1, for the design 21 printed on processed paper, the transfer state was good for a 1.0 mm thick metal component when the pouring temperature was 330°C or less. On the other hand, when the pouring temperature was 340°C or more, relatively small peeling occurred in the runner, so the transfer state was judged to be acceptable. Furthermore, for a 1.5 mm thick metal component, the transfer state was good for a 250°C or less pouring temperature. On the other hand, when the pouring temperature was 260 to 350°C, relatively small peeling occurred in the runner, so the transfer state was judged to be acceptable. Furthermore, when the pouring temperature was 360°C or more, relatively large peeling occurred in the runner, so the transfer state was judged to be unacceptable.

[0042]

[0043] From the above investigation results, the pouring temperature was determined to be 370°C or less. More specifically, for designs 21 printed on unprocessed paper, a pouring temperature of 350°C or less is more preferable. For designs 21 printed on processed paper, a pouring temperature of 330°C or less is more preferable, and a pouring temperature of 250°C or less is even more preferable. Furthermore, from the investigation results shown in Table 1, it is preferable to lower the pouring temperature as the thickness of the metal part to be cast increases.

[0044] Here, Fig. 5 is a macrophotograph showing an example of a metal member manufactured by the manufacturing method of a patterned metal member according to the first embodiment. The top row of Fig. 5 is a macrophotograph of paper 20 on which color printing has been performed on processed paper. The middle row of Fig. 5 is a macrophotograph of a metal member on which a pattern 21 has been transferred by casting. The bottom row of Fig. 5 is a macrophotograph of a metal member on which the surface on which the pattern 21 has been transferred has been cleaned and then clear coated.

[0045] As shown in Fig. 5, the method for manufacturing a patterned metal member according to the first embodiment allows the pattern 21 to be transferred very clearly to the metal surface. The example of color printing on processed paper shown in Fig. 5 is an example in Table 1, where the casting temperature is 300°C and the thickness is 1.0 mm.

[0046] Fig. 6 is an optical microscope photograph showing a comparison of the changes in the surface of paper with a black-and-white printed design before and after casting. Fig. 7 is an optical microscope photograph showing a comparison of the surfaces of the patterned and plain areas of a metal part to which a black-and-white printed design has been transferred. The magnification of each photograph is 200x. The examples of black-and-white printing on unprocessed materials shown in Figs. 6 and 7 are examples in Table 1 where the casting temperature was 300°C and the thickness of the metal part was 1.0 mm.

[0047] As shown in the upper part of Figure 6, many granular black toner particles were found on the surface of the paper before casting. On the other hand, as shown in the lower part of Figure 6, no granular black toner particles were found on the surface of the paper after casting, and only a fibrous paper surface was found. In other words, it is presumed that the granular black toner particles were transferred to the surface of the metal component during casting.

[0048] 7, the surface of the metal part in the plain area where the design 21 has not been transferred is white overall, and the unevenness of the casting surface can be seen. On the other hand, as shown in the lower part of Fig. 7, the surface of the metal part in the design area where the design 21 has been transferred has many black areas, and the unevenness of the casting surface is small. In other words, it is presumed that black toner was transferred to the surface of the metal part during casting, and the surface of that area was flattened.

[0049] <Effect of Tin Purity> Next, the effect of tin purity on the transfer state of the pattern will be described with reference to Fig. 8. Fig. 8 is a set of macrophotographs comparing color patterns transferred to the surfaces of metal members with different tin purities. The macrophotograph shown in the upper row of Fig. 8 has a tin purity of 99.9% by mass, while the macrophotograph shown in the lower row of Fig. 8 has a tin purity of 99.99% by mass. In both cases, the casting temperature was 300°C, and the thickness of the metal member was 1.0 mm.

[0050] As shown in the upper part of Figure 8, when the tin purity was 99.9% by mass, transfer defects A and B were observed in parts of the design 21. On the other hand, as shown in the lower part of Figure 8, when the tin purity was 99.99% by mass, no defects were observed in the transfer of the design 21. In this way, by making the tin purity 99.99% by mass or more, the design 21 transferred to the surface of the metal component made of pure tin can be made clearer.

[0051] Here, Figure 9 is a macrophotograph comparing the raw material and molten surface of 99.9% pure tin and 99.99% pure tin. As shown in the upper left of Figure 9, the 99.9% pure tin raw material is granular with a particle size of about 3 to 5 mm. Furthermore, as shown in the upper right of Figure 9, many inclusions were formed on the surface of the molten material after melting this raw material.

[0052] In contrast, as shown in the lower left of Figure 9, a tin raw material with a purity of 99.99% by mass is in the form of a plate with a length of about 50 mm. Furthermore, as shown in the lower right of Figure 9, almost no inclusions were observed on the surface of the molten metal after melting this tin raw material. It is possible that the defect of pattern 21 with tin with a purity of 99.9% by mass shown in the upper right of Figure 9 is caused by inclusions formed on the surface of the molten metal, as shown in the upper right of Figure 9.

[0053] (Second embodiment) First, a method for manufacturing a patterned metal member according to a second embodiment will be described with reference to Fig. 10. Fig. 10 is a flowchart showing the method for manufacturing a patterned metal member according to the second embodiment. Steps ST1, ST3, and ST4 shown in Fig. 10 are common to steps ST1, ST3, and ST4 shown in Fig. 1, and therefore will not be described.

[0054] In step ST2a shown in Fig. 10, paper is placed on the molten metal to stir the molten metal (molten metal) before pouring the molten metal into the mold in step ST2 shown in Fig. 1. The paper placed on the molten metal is not particularly limited, but may be, for example, oil-absorbent paper such as kitchen paper (paper towel). For example, paper is cut to a predetermined size, and multiple pieces of the paper are placed on the molten metal. Alternatively, a single sheet of paper may be placed on the molten metal.

[0055] Here, with low-melting-point metals having a melting point below the melting point of tin (232°C), the temperature of the molten metal is also low, so for example, oil adhering to the raw material may remain on the molten metal, which may have an adverse effect on the transfer of the pattern 21 by casting.

[0056] Therefore, as shown in Figure 10, in the manufacturing method of a patterned metal part according to this embodiment, in step ST2a, paper is placed on the molten metal and the molten metal is stirred. With this configuration, for example, film-like inclusions (also called "slag") consisting of oils, oxides, etc. formed on the surface of the molten metal (melt surface) can be adsorbed onto the paper and removed. Then, by pouring the molten metal from which the oils, etc. have been removed into the mold 10, the pattern 21 transferred to the surface of the cast metal part can be made clearer. Note that the film-like inclusions on the melt surface may be mostly removed with a spoon or the like before being removed with the paper.

[0057] Here, Fig. 11 is a macrophotograph showing the melting process in step ST2a shown in Fig. 10. As shown in Fig. 11, the tin raw material with a purity of 99.9% by mass is in the form of granules with a particle size of about 3 to 5 mm. When this raw material was melted, the above-mentioned film-like inclusions were formed on the molten metal surface, as shown in the photograph of molten metal surface 1. Note that the photograph of the raw material and molten metal surface 1 shown in Fig. 11 is the same as the photograph of the tin raw material with a purity of 99.9% by mass and the molten metal surface shown in the upper part of Fig. 9.

[0058] Next, as shown in the photograph of molten metal surface 2, most of the inclusions on the molten metal surface were removed using a spoon, resulting in the molten metal surface shown in the photograph of molten metal surface 3. Furthermore, in order to remove inclusions that could not be removed with the spoon, several pieces of oil-absorbing paper were placed on the molten metal surface, as shown in the photograph of molten metal surface 4, and the molten metal was heated to 350 to 450°C and stirred. After that, the oil-absorbing paper was removed, resulting in a clean, mirror-like molten metal surface, as shown in the photograph of molten metal surface 5.

[0059] Here, Fig. 12 is a set of macrophotographs comparing the color patterns transferred to the surface of the metal member when oil absorbent paper is used on the hot water surface and when it is not. The macrophotograph shown in the upper part of Fig. 12 is the same as the macrophotograph shown in the upper part of Fig. 8.

[0060] The macrophotograph shown in the upper part of Figure 12 shows the state of molten metal surface 3 in Figure 11, i.e., molten metal without oil absorbent paper, poured into mold 10, and a pattern 21 transferred onto the surface of the tin. On the other hand, the macrophotograph shown in the lower part of Figure 12 shows the state of molten metal surface 5 in Figure 11, i.e., molten metal whose surface has been cleaned using oil absorbent paper, poured into mold 10, and a pattern 21 transferred onto the surface of the tin.

[0061] As shown in the upper part of Figure 12, when oil absorbent paper was not used, transfer defects A and B were observed in parts of the pattern 21. On the other hand, as shown in the lower part of Figure 12, when oil absorbent paper was used to clean the molten water surface, no transfer defects were observed in the pattern 21.

[0062] In this way, even if a tin raw material with a purity of 99.9% by mass is used, by cleaning the surface of the molten metal with paper, the pattern 21 transferred to the surface of the metal member made of pure tin can be made clearer. The other configurations are the same as those of the method for manufacturing a patterned metal member according to the first embodiment, and therefore a description thereof will be omitted.

[0063] It should be noted that the present disclosure is not limited to the above-described embodiments and can be modified as appropriate without departing from the spirit of the present disclosure. This application claims priority based on Japanese Patent Application No. 2024-097931, filed on June 18, 2024, the entire disclosure of which is incorporated herein by reference.

[0064] 10 Mold 11, 12 Mold 13 Formwork 20 Paper 21 Design

Claims

1. A method for manufacturing a patterned metal component, comprising: a step of placing a sheet material having a pattern on its surface along the inner surface of a mold; and a step of casting a metal component by pouring molten metal into the mold, wherein the pattern is transferred to the surface of the metal component during the casting step.

2. The method for manufacturing a patterned metal member according to claim 1, wherein the sheet material is paper, and the temperature of the molten metal poured into the mold is 370°C or less.

3. The method for manufacturing a patterned metal member according to claim 2, wherein the temperature of the molten metal poured into the mold is 350°C or less.

4. The method for manufacturing a metal member with a design according to claim 2 or 3, wherein the molten metal is a metal containing tin as a main component.

5. The method for manufacturing a metal member with a design according to claim 4, wherein the molten metal is pure tin having a purity of 99% by mass or more.

6. The method for manufacturing a metal part with a design according to claim 5, wherein the purity of the pure tin is 99.9% by mass or more.

7. The method for manufacturing a metal part with a design according to claim 2 or 3, wherein the paper is processed paper.

8. The method for manufacturing a metal member with a design according to any one of claims 1 to 3, wherein the metal member is plate-shaped, the sheet material is arranged so as to stand along the inner surface of the mold in the arranging step, and the metal member is cast so as to stand in the casting step.

9. The method for manufacturing a metal member with a design according to claim 8, wherein in the casting step, the temperature of the molten metal poured into the mold is lowered as the thickness of the metal member increases.

10. A method for manufacturing a patterned metal member as described in claim 8, wherein the mold comprises a pair of mating dies that form a pair of main surfaces of the metal member, and a formwork that is sandwiched between the pair of mating dies and forms the outer edge of the metal member, and in the casting process, the sheet material is sandwiched between one of the pair of mating dies and the formwork, and the molten metal is poured through an opening provided in the upper part of the formwork.

11. The method for manufacturing a patterned metal member according to claim 10, wherein one of the pair of mating dies on which the sheet material is placed is made of metal, and the other of the pair of mating dies is made of non-metal.

12. The method for manufacturing a patterned metal member according to claim 10, wherein the form is made of paper.

13. A method for manufacturing a metal component with a design according to any one of claims 1 to 3, further comprising the steps of: cleaning the surface of the metal component onto which the design has been transferred; and applying a clear coat to the cleaned surface of the metal component.

14. The method for manufacturing a patterned metal member according to any one of claims 1 to 3, wherein paper is placed on the molten metal and the molten metal is stirred before pouring the molten metal into the mold.

15. The method for manufacturing a patterned metal member according to claim 14, wherein the paper placed on the molten metal is oil-absorbent paper.

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