Manufacturing method of metal member

In a manufacturing method of a metal member according to an embodiment, the metal member having an overhang portion is molded together with hollow support members that support the overhang portion, by repeatedly forming a molding layer that is selectively melted and solidified by applying a light beam to a predetermined region of a metal powder layer spread over a pedestal. The manufacturing method includes: providing removal members on the pedestal; integrally forming the support members on the removal members; integrally forming the metal member on the support members; and removing the removal members and the support members, by twisting the removal members, from the removal members, the support members, and the metal member that are formed integrally with each other.

INCORPORATION BY REFERENCE

The disclosure of Japanese Patent Application No. 2015-177814 filed on Sep. 9, 2015 including the specification, drawings and abstract is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a manufacturing method of a metal member, and relates to a manufacturing method of a metal member by use of a three-dimensional molding device, which is a so-called 3D printer, for example.

2. Description of Related Art

A three-dimensional molding device, a so-called 3D printer, comes into the limelight. The three-dimensional molding device molds a member having a three-dimensional shape by applying a light beam to a material such as metal powder or photocurable resin. More specifically, by repeatedly forming a molding layer selectively melted and solidified or cured by applying a light beam to a predetermined region of a material layer, it is possible to manufacture a three-dimensional shaped member in which many molding layers are laminated and integrated.

In a case where a member having an overhang portion is manufactured by use of such a three-dimensional molding device, it is necessary to separate and remove support members after a member as a product is molded together with the support members that support the overhang portion. The support member has a hollow honeycomb structure, which facilitates a removal operation. However, the removal operation of the support members is often performed manually, which takes time. In view of this, a technique to further facilitate the removal operation of the support members and shorten time has been explored.

Japanese Patent Application Publication No. 8-025487 (JP 8-025487 A) describes a support formation method in which a gap is provided between a support member and a resin member so as to facilitate a removal operation of the support member in the resin member molded by a three-dimensional molding device.

In a case where the method described in JP 8-025487 A is applied to molding of a metal member, such a problem may be caused that the metal member is inclined during the molding due to a gap between the support member and the metal member, because the metal member is heavier than the resin member.

Accordingly, the method described in JP 8-025487 A cannot be applied to the manufacturing method of the metal member. The exploring of the technique to facilitate the removal operation of the support members in the manufacturing method of the metal member so as to shorten time still continues.

SUMMARY OF THE INVENTION

The present invention provides a manufacturing method of a metal member. In the manufacturing method, removal members, support members, and a metal member are molded integrally, and by twisting the removal members, it is possible to easily separate and remove the removal members and the support members from the removal members, the support members, and the metal member thus molded integrally.

A manufacturing method of a metal member according to one aspect of the present invention is a manufacturing method for manufacturing a metal member such that the metal member having an overhang portion is molded together with hollow support members that support the overhang portion, by repeatedly forming a molded layer selectively melted and solidified by applying a light beam to a predetermined region of a metal powder layer spread over a pedestal. The manufacturing method includes: a step of providing removal members on the pedestal, the removal members being used for removing the support members; a step of integrally forming the support members on the removal members provided on the pedestal; a step of integrally forming the metal member on the support members formed integrally with the removal members; and a step of removing the removal members and the support members, by twisting the removal members, from the removal members, the support members, and the metal member that are formed integrally with each other. The removal members each include a body portion as a columnar solid member, a uneven structure formed on a bottom face or a side face of the body portion, and a wing portion formed so as to project toward a vertically upper side from a top face of the body portion, and in the step of removing the support members, a torsional force applied to the removal member from outside through the uneven structure is transmitted to a side face of the support member from a side face of the wing portion. With such a configuration, by twisting the removal members, it is possible to easily separate and remove the removal members and the support members.

In the step of integrally forming the support members, the support members may be formed as hollow rectangular columns extending toward the vertically upper side, and a plurality of support members may be formed integrally and arranged so as to form a square honeycomb structure. Such a configuration allows the support members to have rigidity and to hold the metal member. In the meantime, it is possible to easily remove the support members.

Further, in the step of providing the removal members on the pedestal, a plurality of removal members may be provided, and in the step of removing the support members, the removal members placed in an outer periphery may be twisted sequentially along the outer periphery, when the plurality of removal members is viewed from a vertically lower side. With such a configuration, it is possible to decrease the torsional force.

The manufacturing method may further include a step of forming the support members on the pedestal before the step of providing the removal members on the pedestal, and in the step of providing the removal members on the pedestal, the removal members may be formed on the support members formed on the pedestal. Such a configuration facilitates separation of the removal members, the support members, and the metal member that are formed integrally with each other from the pedestal.

Further, the removal member may have a cylindrical shape, the wing portion may be constituted by a plurality of plate-shaped bodies having a width of the same length as a radius of the top face and having a predetermined height and a predetermined thickness, and one ends of the plate-shaped bodies may be placed on a center of the top face so that the plate-shaped bodies are arranged radially, when viewed from the vertically upper side. With such a configuration, it is possible to increase a bonding force between the support member and the wing portion, thereby making it possible to transmit the torsional force from the uneven structure to the support member.

Further, the uneven structure may be a projection portion formed on the bottom face of the body portion.

Further, in the step of providing the removal members on the pedestal, the body portions of the removal members formed in advance may be embedded and fixed in a groove formed in the pedestal, and in the step of integrally forming the support members, the support members may be formed integrally with the wing portions. With such a configuration, it is possible to omit an operation of removing the removal members from the pedestal by use of a band saw.

The body portion of the removal member may have a cylindrical shape, the wing portion may be constituted by one plate-shaped body having a width of the same length as a diameter of the top face and having a predetermined height and a predetermined thickness, and the plate-shaped body may be placed along one direction passing through a center of the top face.

The uneven structure may be a recessed portion formed on the side face of the body portion.

The body portion of the removal member may have a square-column shape, the wing portion may be constituted by a plurality of plate-shaped bodies having a width of the same length as half of one side of a square top face of the body portion and having a predetermined height and a predetermined thickness, one ends of the plate-shaped bodies may be placed on a center of the top face so that the plate-shaped bodies are arranged radially, when viewed from the vertically upper side, the plate-shaped bodies may be placed such that an angle formed between adjacent plate-shaped bodies is 90°, a plurality of removal members may be arranged in a matrix form, and the removal members may be arranged diagonally relative to edges of the metal member, when viewed from the vertically lower side.

The body portion of the removal member may have a square-column shape, the wing portion may be constituted by four plate-shaped bodies having a width of the same length as one side of a square top face of the body portion and having a predetermined height and a predetermined thickness, and the four plate-shaped bodies may be connected along edges of the top face of the body portion in a box shape.

The body portion of the removal member may have a shape of a hexagonal column, in the hexagonal column, a corner part formed between adjacent side faces of the body portion may be formed in a round shape, and the removal members may be arranged such that each of six side faces of the body portion is opposed to a side face of a corresponding one of body portions adjacent to the body portion.

A recessed portion may be formed on the bottom face of the body portion of the removal member.

According to the present invention, it is possible to provide a manufacturing method of a metal member, the manufacturing method attaining easy separation and removal of removal members and support members by twisting the removal members.

DETAILED DESCRIPTION OF EMBODIMENTS

The following describes a best mode for carrying out the present invention with reference to the attached drawings. However, the present invention is not limited to the following embodiment. Further, the following description and drawings are simplified appropriately for clarification of the description.

A manufacturing method of a metal member according to the embodiment is described. The manufacturing method of the metal member of the present embodiment is a manufacturing method for manufacturing a metal member of a shape having an overhang portion in a three-dimensional molding device (3D printer).

FIG. 1is a perspective view exemplifying removal members, support members, and a metal member in the manufacturing method of the metal member according to the embodiment.FIG. 2is a flow chart exemplifying the manufacturing method of the metal member according to the embodiment.

As illustrated inFIG. 1, in the present embodiment, in a manufacturing process of a metal member10, support members20are formed so as to support an overhang portion11in the metal member10. Note that, InFIG. 1, only the overhang portion11in the metal member10is illustrated, and the other parts of the metal member10are omitted. Further, removal members30for removing the support members20when the finished metal member10is taken out are formed. The manufacturing method of the metal member10according to the embodiment will be described separately in terms of a formation method (steps S1to S3inFIG. 2) of the metal member10, the support members20, and the removal members30, and a removal method (step S4inFIG. 2) of the support members20and the removal members30. First will be described the formation method of the metal member10, the support members20, and the removal members30.

As illustrated inFIG. 1, a pedestal40is prepared. The pedestal40has a plate shape, for example. A top face41of the pedestal40is level. InFIG. 1, an XYZ rectangular coordinate system is introduced for purposes of this description. A Z-direction is a vertical direction and is a direction perpendicular to the top face41of the pedestal40. An X-direction and a Y-direction are a horizontal direction and are directions parallel to the top face41of the pedestal40.

Then, metal powder is spread over the pedestal40in a layer form. The metal powder is, for example, maraging steel, Inconel 718, or the like. The metal powder is spread closely and thinly in a layer form having a thickness of 0.04 mm, for example, by use of a recoater. Then, a light beam is applied to a predetermined region of a metal powder layer thus spread over the pedestal40, so as to form a molding layer that is selectively melted and solidified. In the molding layer thus melted and solidified, a sectional shape of at least one member out of the metal member10, the support members20, and the removal members30is formed. Unsintered metal powder remains in a part that is not melted and solidified. In a part to be melted and solidified, a three-dimensional molding device is controlled by use of a STL-type 3D data for sintering.

Subsequently, metal powder is spread over the formed molding layer and the unsintered metal powder. Then, a light beam is applied to a predetermined region so as to form a molding layer. As such, spreading of the metal powder and the application of a light beam are repeated, so as to laminate the molding layers. The molding layers are piled upward in a unit of a dozens of microns. By piling up the molding layers to a predetermined height, the removal members30are formed on the pedestal40together with a part of the metal member10or the support members20. Thus, as illustrated in step S1ofFIG. 2, the removal members30for removing the support members20are provided on the pedestal40.

In the present embodiment, the removal members30are made of the same metal powder layer as the support members20and the metal member10. Accordingly, the removal members30, the support members20, and the metal member10can be formed continuously and integrally with each other. At this time, 3D data for sintering includes data of the removal members30.

FIGS. 3A to 3Dare views exemplifying the removal member in the manufacturing method of the metal member according to the embodiment.FIG. 3Ais a perspective view,FIG. 3Bis a top view,FIG. 3Cis a front view, andFIG. 3Dis a side view.

As illustrated inFIG. 1andFIGS. 3A to 3D, the removal member30is formed on the pedestal40. A vertical relationship is described based on a state where the removal members30are formed on the top face41of the pedestal40. Accordingly,FIG. 3Ais a perspective view of the removal member30when viewed from a vertical lower side.

The removal member30includes a body portion30a, which is a columnar solid member. The body portion30aof the removal member30has a cylindrical shape, for example. The removal member30includes a wing portion32formed so as to project upward in a vertical direction from a part of a top face31of the cylindrical body portion30a. The wing portion32is constituted by a plurality of, e.g., four plate-shaped bodies32ahaving a width of the same length as a radius of the top face31and having a predetermined height and a predetermined thickness. One ends of the plate-shaped bodies32aare placed on a center31aof the top face31so that the plate-shaped bodies32aare arranged radially, that is, in a cross shape when viewed from a vertically upper side. Further, the plate-shaped bodies32aare placed so that an angle formed between adjacent plate-shaped bodies32ais equally 90°. Note that the angles between adjacent plate-shaped bodies32amay not be equal to each other.

The removal member30has a uneven structure formed on a bottom face33of the body portion30a. For example, the uneven structure is a recessed portion34. When the recessed portion34is viewed from a vertically lower side, a shape of the recessed portion34is a hexagonal shape. An inner surface of the recessed portion34is constituted by an inner side surface35and a ceiling surface36. The inner side surface35is formed between the bottom face33and the ceiling surface36. An angle formed between the inner side surface35and a horizontal plane is 90°. An angle formed between the ceiling surface36and the horizontal plane is 45° or more. If the inner surface of the recessed portion34has an angle of 45° or more with respect to the horizontal plane, it is not necessary to form the support member20for supporting the inner surface of the recessed portion34. Conversely, if the angle with respect to the horizontal plane is less than 45° and there is a part projecting in the air, the part must be supported by the support member20.

A plurality of removal members30is formed on the pedestal40in a state where their bottom faces33face downward. When many support members20are attached to one removal member30, a torsional force necessary to twist the removal member30increases. Accordingly, the plurality of removal members30is formed so as to prevent an increase in the number of support members20to be attached to one removal member30. This makes it possible to lower a force necessary to twist the removal member30.

A sectional area of the removal member30along a horizontal direction is preferably around 0.8 to 2.5 cm2. The removal members30are placed at positions where they do not adhere to each other. Note that the recessed portion34may be formed as a minus-shaped hole, a plus-shaped hole, or a torx-shaped (registered trademark) (star-shaped) hole, instead of a hexagonal hole.

The wing portion32preferably has a shape that allows a torsional force applied to the removal member30via the uneven structure to be transmitted to a side face of the support member20from a side face of the wing portion32. The wing portion32preferably has a shape having a large contact area with the support member20in a direction perpendicular to a direction of the torsional force. As such, if the wing portion32has a shape that allows the torsional force to be transmitted to the side face of the support member20from the side face of the wing portion32, the wing portion32may have a uneven shape, a hole shape, a wing shape, or the like instead of the plate-shaped body32a.

Subsequently, metal powder is spread over the pedestal40in a layer form, and then, a light beam is applied to a predetermined region of a metal powder layer thus formed, so as to form a molding layer that is selectively melted and solidified. This operation is repeated, so as to laminate molding layers. Hereby, the support members20are formed together with part of the metal member10. As such, as illustrated in step S2ofFIG. 2, the support members20are integrally formed on the removal members30provided on the pedestal40.

FIG. 4Ais a horizontal sectional view exemplifying the support members in the manufacturing method of the metal member according to the embodiment, andFIG. 4Bis a perspective view exemplifying the support members in the manufacturing method of the metal member according to the embodiment.

As illustrated inFIGS. 1, 4A, and 4B, when the support members20are formed integrally, for example, the support member20is formed as a hollow rectangular column extending toward the vertically upper side, and a plurality of support members20is arranged in an integrated manner so as to have a square honeycomb structure. Since the support members20are formed to have the square honeycomb structure, the support members20can have rigidity to hold the metal member10. In the meantime, the support members20can be easily removed. The support member20has a cell structure in which rectangular columns having a square section with one side of 1 mm and having a wall thickness of 0.15 mm are collectively provided without any gap. InFIG. 1, the support members20are illustrated schematically.

When viewed from the vertically upper side, a penetration groove21, called a fragment, is formed every 5 mm in two perpendicular directions along which the rectangular columns are arranged in the square honeycomb structure. For example, a width of the penetration groove21is 0.2 mm. Due to the penetration grooves21, the support members20are formed in a grid shape at intervals of 5 mm when viewed from the vertically upper side. When viewed from the vertically upper side, 4×4 support members20are placed in one grid. The penetration grooves21are penetrated through the support members20from upper ends to bottom ends thereof. Due to the penetration grooves21, the support members20cannot be easily removed. A hollow of the rectangular column is filled with the metal powder remaining in an unsintered state. As described above, as the number of support members20connected to the removal member30is smaller, a torsional force to twist the removal member30can be made small. However, in that case, the number of removal members30increases, which increases the number of times of twisting. The number of support members20to be connected to one removal member30is set to an appropriate number.

Subsequently, metal powder is spread over the pedestal40, and then, a light beam is applied to a predetermined region of a metal powder layer thus formed, so as to form a molding layer that is selectively melted and solidified. This operation is repeated, so as to laminate molding layers. Hereby, the metal member10is formed. That is, by repeatedly forming a molding layer that is selectively melted and solidified by applying a light beam to a predetermined region of a metal powder layer spread over the pedestal40, the metal member10having the overhang portion11is molded together with the hollow support members20that support the overhang portion11. As such, as illustrated in step S3inFIG. 2, the metal member10is integrally formed on the support members20formed integrally with the removal members30. Hereby, a structure illustrated inFIG. 1is formed.

Next will be described the removal method of the support members20and the removal members30in the manufacturing method of the metal member10. For example, a band saw (flat saw) is placed along a line A-A′ illustrated inFIG. 1. Then, the band saw is moved along the top face41of the pedestal40. Hereby, the metal member10, the support members20, and the removal members30that are formed integrally with each other are separated from the pedestal40.

FIGS. 5A and 5Bare views of the removal members separated from the pedestal, when viewed from the vertically lower side, in the manufacturing method of the metal member according to the embodiment. As illustrated inFIGS. 5A and 5B, when the metal member10, the support members20, and the removal member30separated from the pedestal40are viewed from the vertically lower side, the recessed portions34appear on the bottom faces33of the removal members30. Note that, after they are separated from the pedestal40, the metal powder remains in the recessed portions34, so the metal power is removed.

Then, as illustrated in step S4ofFIG. 2, the removal members30are twisted so as to remove the removal members30and the support members20from the removal members30, the support members20, and the metal member10that are formed integrally with each other. The torsional force applied to the removal member30from outside through the uneven structure of the removal member30is transmitted to the side faces of the support members20from the side face of the wing portion32. Hereby, the support members20are removed.

More specifically, a hexagonal wrench is inserted into the hexagonal recessed portion34(the uneven structure) formed on the bottom face of the removal member30. The removal member30is then twisted by twisting the hexagonal wrench. This accordingly twits the wing portion32. As a result, the torsional force is transmitted to the support members20. Hereby, the support members20are removed.

As illustrated inFIG. 5A, when a plurality of removal members30is viewed from the vertically lower side, three bottom faces33adjacent to each other are arranged so as to be placed at three corners of an equilateral triangle. That is, the bottom faces33are arranged in a direction along a Y-axis and in a direction inclined by 30° from an X-axis. The removal members30are twisted and removed in an order that achieves a shortest distance by drawing with a single stroke of the brush.

At the time of twisting and removing the support members20, it is preferable that the removal members30placed on an outer periphery be sequentially twisted along the outer periphery when the plurality of removal members30is viewed from the vertically lower side, as illustrated inFIG. 5B. The removal members30at corner parts can be removed at a small torsional force to remove the removal members30. At the corner parts, a contact area between the side faces of the removal members30is small, so the torsional force can be made small. Therefore, the removal members30placed at the corner parts are easily removed. By removing the removal members30in a spiral shape along the outer periphery, occurrence numbers of the removal members30placed at the corner parts are increased. Hereby, it is possible to decrease the torsional force at the time of removing all the removal members30from an integrally molded product. On the other hand, in a case where the removal members30are removed from the removal member30placed in a central part, bonding forces between adjacent removal members30and between adjacent support members20are large. Therefore, a large torsional force is required. By twisting all the removal members30, the removal members30and the support members20are removed from the metal member10. Thus, the metal member10is manufactured.

According to the manufacturing method of the metal member10of the present embodiment, by twisting the removal members30, the removal members30and the support members20are removed from the removal members30, the support members20, and the metal member10that are formed integrally with each other. Here, the removal member30is a columnar solid member, and includes the uneven structure formed on the bottom face33or the side face37of the body portion30a, and the wing portion32formed so as to project toward vertically upper side from the top face of the body portion30a. At the time of removing the support members20, the torsional force is applied to the removal member30from outside through the uneven structure, so that the torsional force is transmitted to the support members20via the wing portion32. Accordingly, by twisting the removal members30, the removal members30and the support members20can be easily separated and removed.

The wing portion32is provided in the removal member30. Hereby, the torsional force applied to the removal member30from outside through the uneven structure is transmitted to the side faces of the support members20from the side face of the wing portion32. The wing portion32has a shape having a large contact area with the support member20in the direction perpendicular to the direction of the torsional force. This causes a bonding force between the removal member30and the support member20to be larger than a bonding force between the support member20and the metal member10. Otherwise, a force (twist, bending moment) transmitted from the removal member30is absorbed by deformation of the support member20, so that a force to work on the boundary surface between the metal member10and the support member20decreases. As a result, the removal member30comes off from the support member20from a boundary surface therebetween.

FIG. 6is a perspective view exemplifying support members20and a metal member10in a manufacturing method of a metal member according to a comparative example. As illustrated inFIG. 6, in the comparative example, the removal members30are not provided. In view of this, as a removal method of support members20in the comparative example, the following methods are conceivable, for example. That is, (a) the support members20are removed by water jet; (b) the support members20are removed by electric field grinding; (c) the support members20are removed by beating and crushing with a graver; and (d) the support members20are cut and removed by machining.

However, the method (a) of the comparative example requires a high running cost in addition to a processor itself being expensive. Further, a cutting thickness has a limit (several centimeters), and it is difficult to form small parts. Besides, it takes a long time for cutting. Further, there is such a problem that rust occurs in the metal member due to moisture content. In the method of (b) of the comparative example, an environmental load is large due to waste water of an electrolytic solution and a sludge process, which increases a cost. In the method of (c) of the comparative example, a work load to an operator increases. Further, by beating with the graver, unsintered metal powder is scattered. Accordingly, it is necessary to perform a treatment to reduce the influence of such dust. In the method of (d) of the comparative example, the machining itself is expensive. As described above, in the comparative example, it is difficult to easily separate and remove the support members20.

On the other hand, in the present embodiment, the removal members30are twisted so that the removal members30and the support members20are removed from the removal members30, the support members20, and the metal member10that are formed integrally with each other. This makes it possible to cut the cost and reduce the environmental load in addition to the afore-mentioned effects. Further, it is possible to easily perform the removal by twisting and to restrain the occurrence of dust.

(Modification 1) Next will be described Modification 1. In Modification 1, a body portion30aof a removal member30is formed as a rectangular column instead of a cylinder. Further, support members20are formed between a pedestal40and removal members30.

FIG. 7Ais a perspective view exemplifying removal members, support members, and a metal member according to Modification 1 of the embodiment;FIG. 7Bis a perspective view exemplifying the removal member; andFIG. 7Cis a view of the removal members separated from the pedestal, when viewed from a vertically lower side.

As illustrated inFIGS. 7A to 7C, the body portion30aof the removal member30has a rectangular-column shape, e.g., a square-column shape, for example. A top face31of the body portion30ahas a square shape. A wing portion32is constituted by one plate-shaped body32ahaving a width of the same length as one side of the top face31and having a predetermined height and a predetermined thickness. The plate-shaped body32apasses through a center of the top face31so as to be placed along one direction, e.g., the X-direction. A recessed portion34is formed on a bottom face33of the body portion30aof the removal member30. The recessed portion34has a structure similar to that of the embodiment.

In Modification 1, the body portion30aof the removal member30is a square column. The removal members30are placed in a matrix form along the X-direction and the Y-direction. The removal members30are formed on the support members20formed on the pedestal40. Such a configuration is formed by the following formation method. That is, the support members20are formed on the pedestal40before the removal members30are provided on the pedestal40. After that, the removal members30are formed on the support members20thus formed on the pedestal40. As such, the configuration illustrated inFIG. 7Ais formed. After that, the removal members30, the support members20, and the metal member10that are formed integrally with each other are separated from the pedestal40. By forming the support members20between the removal members30and the pedestal40, it is possible to easily separate, from the pedestal40, the removal members30, the support members20, and the metal member10that are formed integrally with each other.

(Modification 2) Next will be described Modification 2. In Modification 2, a recessed portion34is not formed on a bottom face33of a body portion30aof a removal member30, but the recessed portion34is formed on a side face37of the body portion30a.

FIG. 8Ais a perspective view exemplifying removal members, support members, and a metal member according to Modification 2 of the embodiment;FIG. 8Bis a perspective view exemplifying the removal member; andFIG. 8Cis a view of the removal members separated from a pedestal, when viewed from a vertically lower side.

As illustrated inFIGS. 8A to 8C, the body portion30aof the removal member30has a cylindrical shape, for example. A top face31of the body portion30ahas a circular shape. A wing portion32is constituted by one plate-shaped body32ahaving a width of the same length as a diameter of the top face31and having a predetermined height and a predetermined thickness. The plate-shaped body32apasses through a center of the top face31so as to be placed along one direction, e.g., the X-direction. The recessed portion34is not formed on the bottom face33of the body portion30aof the removal member30. A uneven structure of the removal member30is the recessed portion34formed on the side face37of the body portion30a. An inner surface of the recessed portion34is formed so as to have an angle of 45° or more with respect to a horizontal plane so as not to overhang. By forming the recessed portion34on the side face of the removal member30, it is possible to twist the removal members30without separating, from the pedestal40, the metal member10, the support members20, and the removal members30that are formed integrally with each other.

(Modification 3) Next will be described Modification 3. In Modification 3, one wing portion32is provided in a removal member30.

FIG. 9Ais a perspective view exemplifying removal members, support members, and a metal member according to Modification 3 of the embodiment;FIG. 9Bis a perspective view exemplifying the removal member; andFIG. 9Cis a view of the removal members separated from a pedestal, when viewed from a vertically lower side.

As illustrated inFIGS. 9A to 9C, a body portion30aof the removal member30has a cylindrical shape. A top face31of the body portion30ahas a circular shape. A wing portion32is constituted by one plate-shaped body32ahaving a width of the same length as a diameter of the top face31and having a predetermined height and a predetermined thickness. The plate-shaped body32apasses through a center of the top face31so as to be placed along one direction, e.g., the X-direction. A recessed portion34is formed on a bottom face33of the body portion30aof the removal member30. The recessed portion34has a structure similar to that of the embodiment. The removal members30are placed in a matrix form in the X-direction and the Y-direction.

(Modification 4) Next will be described Modification 4. In Modification 4, removal members30are provided so as to be embedded in a pedestal40.

FIG. 10Ais a perspective view exemplifying removal members, support members, and a metal member according to Modification 4 of the embodiment;FIG. 10Bis a perspective view exemplifying the removal member; andFIG. 10Cis an enlarged view exemplifying a boundary surface between the metal member and the support members.

As illustrated inFIG. 10A, at the time of providing the removal members30on the pedestal40, body portions30aof the removal members30formed in advance are embedded in a groove formed in the pedestal40so as to be fixed thereto. The body portion30aof the removal member30has a square-column shape. The support members20are formed integrally with wing portions32(not shown) on top faces31of the removal members30. A square groove, viewed from a vertically upper side, is formed in the pedestal40. A plurality of removal members30is arranged in a matrix form and embedded in the groove thus formed in the pedestal40. With such a configuration, an operation of removing the removal members30from the pedestal40by use of a band saw can be omitted. As illustrated inFIG. 10B, a recessed portion34is formed on a bottom face33of the removal member30. The recessed portion34has a structure similar to that of the embodiment.

Further, in Modification 4, as illustrated inFIG. 10C, at the time of forming the support members20integrally, a plurality of notches22is formed at predetermined intervals on a boundary surface23between the support members20and the metal member10. By forming the notches22on the boundary surface23, a bonding force between the support members20and the metal member10is lowered as compared with a bonding force between the removal members30and the support members20. Accordingly, by twisting the removal members30, the removal members30and the support members20can be easily removed from the removal members30, the support members20, and the metal member10that are formed integrally with each other.

(Modification 5) Next will be described Modification 5. In Modification 5, a wing portion is formed of three pieces.FIG. 11Ais a perspective view exemplifying removal members, support members, and a metal member according to Modification 5 of the embodiment;FIG. 11Bis a perspective view exemplifying the removal member;FIG. 11Cis a perspective view exemplifying the removal members and the metal member according to Modification 5 of the embodiment; andFIG. 11Dis a view of the removal members separated from a pedestal, when viewed from a vertically lower side.

As illustrated inFIGS. 11A to 11D, a body portion30aof the removal member30has a cylindrical shape. A wing portion32is constituted by three plate-shaped bodies32ahaving a width of the same length as a radius of a top face31and having a predetermined height and a predetermined thickness. One ends of the plate-shaped bodies32aare placed on a center31aof the top face31so that the plate-shaped bodies32aare arranged radially, when viewed from a vertically upper side. Further, the plate-shaped bodies32aare placed so that an angle formed between adjacent plate-shaped bodies32ais 120°. A recessed portion34is formed on a bottom face33of the body portion30aof the removal member30. The recessed portion34has a structure similar to that of the embodiment. When a plurality of removal members30is viewed from the vertically lower side, the removal members30are arranged in the same manner as the embodiment. Note that the number of plate-shaped bodies32ais not particularly limited. For example, six plate-shaped bodies32amay be placed radially so that an angle between adjacent plate-shaped bodies32ais 60°.

(Modification 6) Next will be described Modification 6. In Modification 6, a projection portion is formed on a bottom face33of a body portion30aof a removal member30.FIG. 12is a perspective view exemplifying the removal member according to Modification 6 of the embodiment.

As illustrated inFIG. 12, the body portion30aof the removal member30has a cylindrical shape. A wing portion32has a structure similar to that of Modification 5. The removal member30has a uneven structure formed on the bottom face33of the body portion30a. The uneven structure is a projection portion38having a hexagonal-column shape and formed on the bottom face. When the projection portion38is viewed from a vertically lower side, a shape of the projection portion38is a hexagonal shape. The bottom face33except the projection portion38is formed so that an angle formed with respect to a horizontal plane is 45° or more. In the present modification, a torsional force is applied by sandwiching the projection portion38with a spanner or the like. With such a configuration, it is possible to increase options about a method for transmitting the torsional force.

(Modification 7) Next will be described Modification 7. In Modification 7, removal members30are arranged diagonally relative to edges of a metal member10, when viewed from a vertically upper side.

FIG. 13Ais a perspective view exemplifying removal members, support members, and a metal member according to Modification 7 of the embodiment;FIG. 13Bis a perspective view exemplifying the removal member;FIG. 13Cis a perspective view exemplifying the removal members and the metal member according to Modification 7 of the embodiment; andFIG. 13Dis a view of the removal members separated from a pedestal, when viewed from a vertically lower side.

As illustrated inFIGS. 13A to 13D, a body portion30aof the removal member30has a square-column shape. A wing portion32is constituted by a plurality of, e.g., four plate-shaped bodies32ahaving a width of the same length as half of one side of a square top face31and having a predetermined height and a predetermined thickness. Further, one ends of the plate-shaped bodies32aare placed on a center31aof the top face31so that the plate-shaped bodies32aare arranged radially, that is, in a cross shape when viewed from the vertically upper side. Further, the plate-shaped bodies32aare placed so that an angle formed between adjacent plate-shaped bodies32ais 90°. A recessed portion34has a structure similar to that of the embodiment. A plurality of removal members30is arranged in a matrix form. However, as illustrated inFIG. 13D, the removal members30are arranged diagonally relative to the edges of the metal member10, when viewed from the vertically lower side.

(Modification 8) Next will be described Modification 8. In Modification 8, a wing portion32of a removal member30has a recessed shape.FIG. 14Ais a perspective view exemplifying removal members, support members, and a metal member according to Modification 8 of the embodiment;FIG. 14Bis a perspective view exemplifying the removal member;FIG. 14Cis a perspective view exemplifying the removal members and the metal member according to Modification 8 of the embodiment; andFIG. 14Dis a view of the removal members separated from a pedestal, when viewed from a vertically lower side.

As illustrated inFIGS. 14A to 14D, a body portion30aof the removal member30has a square-column shape. The wing portion32is constituted by four plate-shaped bodies32ahaving a width of the same length as one side of a square top face31and having a predetermined height and a predetermined thickness. Further, the four plate-shaped bodies32aare connected along edges of the top face31of the body portion30ain a box shape. A recessed portion51is formed in a central part of the wing portion32. A recessed portion34is formed on a bottom face33of the body portion30aof the removal member30. The recessed portion34has a structure similar to that of the embodiment. When a plurality of removal members30is viewed from the vertically lower side, the removal members30are arranged in the same manner as Modification 1.

(Modification 9) Next will be described Modification 9. In Modification 9, a body portion30aof a removal member30is formed in a shape of a hexagonal column. In the hexagonal column, a corner part formed between adjacent side faces is formed in an R-shape (a round shape).

FIG. 15is a view of removal members according to Modification 9 of the embodiment, when viewed from a vertically lower side after the removal members are separated from a pedestal. As illustrated inFIG. 15, the body portion30aof the removal member30has a shape of a hexagonal column. In the hexagonal column, a corner part formed between adjacent side faces is formed in an R-shape (a round shape). A recessed portion34is formed on a bottom face33of the body portion30a. The recessed portion34has a hexagonal shape, when viewed from the vertically lower side. An inside of the recessed portion34has a structure similar to that of the embodiment. When a plurality of removal members30is viewed from the vertically lower side, the removal members30are placed in a staggered manner. That is, each of six side faces37aof the body portion30ais placed so as to be opposed to a side face37aof a corresponding one of its adjacent body portions30a. Hereby, when the plurality of removal members30is viewed from the vertically lower side, three bottom faces33adjacent to each other are arranged so as to be placed at three corners of an equilateral triangle. That is, the bottom faces33are arranged in a direction along the Y-axis and in a direction inclined by 30° from the X-axis.

The embodiment of the manufacturing method of the metal member according to the present invention has been described above, but the present invention is not limited to the above configuration, and the above embodiment can be modified without departing from a technical idea of the present invention.

For example, the bottom face33and the side face37of the body portion30aof the removal member30both may have the uneven structure. Further, the shapes of the wing portions32and the shapes of the recessed portions34of the removal members30may be selected appropriately and used in combination.