JP7010799B2 - Structure manufacturing method and structure - Google Patents

Description

The present invention relates to a method for manufacturing a structure and the structure.

In casting, which is a method of manufacturing machine parts, first, a wooden mold (which may be metal or resin) that serves as a model of the product is manufactured, a sand mold is made based on the wooden mold, and molten cast iron is poured into this sand mold. This forms a cast article in the sand mold cavity. However, in such casting, it takes a lot of man-hours to manufacture a wooden mold or a sand mold, and the lead time until a finished product is obtained becomes long. Further, in the case of small-quantity production, the cost of wooden molds and sand molds is added to the product, which is a factor of increasing the manufacturing cost.

On the other hand, there is an increasing need for modeling using a 3D printer as a new means of production, and research and development are being promoted toward the practical application of modeling using metal materials. A 3D printer for modeling a metal material uses a heat source such as a laser, an electron beam, or an arc to melt a metal powder or a metal wire, and laminates the molten metal to produce a model.

As a technique for laminating such molten metals to form a modeled object, there is known a technique for manufacturing a mold using a bead formed by a filler material supplied from a welding torch (for example, Patent Document). 1). Patent Document 1 describes a step of generating shape data expressing the shape of a mold, a step of dividing a mold into a laminate along a contour line based on the generated shape data, and a obtained laminate. A method of manufacturing a mold including a step of creating a moving path of a welding torch for supplying a filler material based on the shape data of the above is described.

Patent Document 2 describes a manufacturing method in which a metal molded body having a hollow portion is manufactured by using a metal laminated molding method, and the metal molded body is cast and wrapped to manufacture a cast product in which the hollow portion is communicated with the outside. There is.

Japanese Patent No. 3784539 Japanese Unexamined Patent Publication No. 2014-113610

However, the technique of Patent Document 1 relates to a method for manufacturing a mold for mass-producing machine parts, and does not describe a method for manufacturing machine parts, particularly a method for manufacturing machine parts produced in small quantities. .. According to the technique of Patent Document 2, in order to produce a cast article having a hollow portion by casting and wrapping a metal molded body formed by a metal laminated molding method, for producing a sand mold or a sand mold for casting and wrapping a metal molded body. The wooden pattern is indispensable and the lead time is long. In addition, when producing in small quantities, there remains a problem regarding the cost of wooden molds and sand molds.

Further, in the case of manufacturing a cast article as described above, the metal molded body is deformed by thermal expansion in the pouring step of pouring the casting water into the mold. Therefore, the following problems will occur.
(1) The metal molded body is heated by pouring and thermally expanded, and residual deformation occurs after cooling. Therefore, the product shape does not match the design.
(2) When the cast metal solidifies during the elastic deformation of the metal forming body even if the metal forming body undergoes temporary thermal deformation during pouring and the deformation returns to the original shape after cooling. In, a gap is generated at the interface between the cast portion after cooling and the metal molded body, and both are not completely integrated.

The present invention has been made in view of the above-mentioned circumstances, shortening the lead time when manufacturing a structure, and suppressing thermal deformation of the outer shell that occurs during and after pouring the casting portion. It is an object of the present invention to provide a method for manufacturing a structure capable of improving product quality and a structure.

The present invention has the following configuration.
(1) A method for manufacturing a structure.
A molding process in which beads obtained by melting and solidifying a filler metal are laminated on a base and the outer shell of the structure is laminated and formed.
The joining process of joining the reinforcing member to the outer shell,
A casting process in which casting water is poured into the inner space of the outer shell to form a casting portion inside the outer shell.
Have,
The joining step is a method for manufacturing a structure including a step of welding the reinforcing member, which is separate from the outer shell, to the inner space of the outer shell .
(2) A laminated model in which continuous linear layers that are closed in a plan view are laminated, and an outer shell that defines an inner space that is a closed space inside the laminated body.
A reinforcing member welded to the inside of the outer shell and made of at least one metal block material,
A casting portion formed in the inner space of the outer shell and
Structure with.

According to the present invention, the lead time when manufacturing a structure can be shortened, and the thermal deformation of the outer shell generated during and after pouring of the casting portion can be suppressed to improve the product quality.

It is a schematic block diagram which shows typically the manufacturing system of the structure of this invention. It is a perspective view of the structure of 1st configuration example. (A) and (B) are process explanatory views showing a procedure for forming an outer shell and ribs of the structure shown in FIG. FIG. 3 is a cross-sectional view taken along the line AA of the structure shown in FIG. 2 after solidification of the cast water in the inner space of the outer shell. It is a reference figure corresponding to FIG. 4 which shows the case where the rib is not provided in the outer shell. It is a schematic block diagram of the structure formed in an annular shape. It is a perspective view of the structure of the 2nd configuration example. (A), (B), and (C) are process explanatory views showing a procedure for forming an outer shell and a support material of the structure shown in FIG. 7. It is a schematic partial sectional view of the outer shell in a casting process. It is a BB sectional view of the structure shown in FIG. 7 after solidification of the cast hot water in the inner space of the outer shell. It is sectional drawing corresponding to FIGS. 4 and 10 of the structure of the 3rd configuration example. It is a schematic partial sectional view which shows the other structural example of a structure.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the structure of the present invention, an outer shell to be an outer wall of the structure is formed by laminated molding described later, and casting water is poured into an inner space defined inside the formed outer shell, and the inside of the outer shell is formed. Manufactured by forming a casting.

FIG. 1 is a schematic configuration diagram schematically showing a manufacturing system for the structure of the present invention.
The structure manufacturing system 100 includes a laminated modeling device 11, a casting device 13, and a controller 15 that controls the laminated modeling device 11 in an integrated manner. The controller 15 may be controlled including the casting device 13.

The laminated modeling device 11 has a welding robot 19 having a torch 17 on the tip shaft, and a filler material supply unit 23 that supplies the filler material (welding wire) M to the torch 17.

The casting apparatus 13 has a crucible 27 for storing the casting water 25 heated by a heating furnace (not shown), and the casting water 25 can be supplied to a desired position by a pouring mechanism (not shown). As the laminated modeling device 11 and the casting device 13, existing devices are used in this configuration, respectively.

The controller 15 has a CAD / CAM unit 31, an orbit calculation unit 33, a storage unit 35, and a control unit 37 to which these are connected.

The welding robot 19 is an articulated robot, and the filler metal M is continuously supplied to the torch 17 provided on the tip shaft. The position and posture of the torch 17 can be arbitrarily set three-dimensionally within the range of the degree of freedom of the robot arm. The welding robot 19 is not limited to the articulated robot, and may be, for example, an orthogonal robot in which the head moves along axes orthogonal to each other.

The torch 17 has a shield nozzle (not shown), and shield gas is supplied from the shield nozzle. The arc welding method may be either a consumable electrode type such as shielded metal arc welding or carbon dioxide arc welding, or a non-consumable electrode type such as TIG welding or plasma arc welding, and is appropriately selected according to the structure to be manufactured. ..

For example, in the case of the consumable electrode type, the contact tip is arranged inside the shield nozzle, and the filler metal M to which the melting current is supplied is held by the contact tip. The torch 17 generates an arc from the tip of the filler M in a shield gas atmosphere while holding the filler M.

The filler material M is supplied from the filler material supply unit 23 to the torch 17 by a feeding mechanism (not shown) attached to a robot arm or the like. As the filler M, any commercially available welding wire can be used. For example, it is defined by MAG welding and MIG welding solid wire (JIS Z 3312) for mild steel, high tension steel and low temperature steel, arc welding flux containing wire for mild steel, high tension steel and low temperature steel (JIS Z 3313) and the like. Wire can be used.

The heat source for melting the filler metal M is not limited to the above-mentioned arc. For example, a heat source by another method such as a heating method using both an arc and a laser, a heating method using plasma, and a heating method using an electron beam or a laser may be adopted. When an arc is used, a bead can be easily formed regardless of the material and structure while ensuring the shielding property. When heating with an electron beam or a laser, the amount of heating can be controlled more finely, the state of the welded bead can be maintained more appropriately, and the quality of the laminated model can be further improved.

The CAD / CAM unit 31 creates shape data of the laminated model W which is the outer shell of the structure to be manufactured, and then divides the data into a plurality of layers to generate layer shape data representing the shape of each layer. The trajectory calculation unit 33 obtains the movement trajectory of the torch 17 based on the generated layer shape data. The storage unit 35 stores data such as the generated layer shape data and the movement locus of the torch 17.

The control unit 37 drives the welding robot 19 by executing a drive program based on the layer shape data stored in the storage unit 35 and the movement locus of the torch 17.

When the filler metal M continuously fed is melted and solidified while the torch 17 is moved by the drive command of the control unit 37, the linear bead 43 which is the molten solidified body of the filler metal M is placed on the base 41. Is formed.

In the manufacturing system 100 of the structure having the above structure, the above-mentioned laminated model W is modeled on the base 41 by the laminated modeling device 11. That is, the bead 43 obtained by melting and solidifying the filler metal M is formed on the plate-shaped base 41 to form a linear shape closed in a plan view. By sequentially laminating the beads 43, the beads 43 are formed into a closed linear layer in a continuous state without gaps. The linear layers are laminated in the vertical direction without gaps to form a bottomed tubular laminated model W.

The base 41 is made of a metal plate such as a steel plate, and basically a base 41 larger than the bottom surface (bottom layer surface) of the laminated model W is used. Further, the base 41 is not limited to a plate shape, but may have another shape such as a block body or a rod shape.

The casting apparatus 13 pours the casting water 25 into the inner space 45 of the formed laminated model W. When the poured casting water 25 solidifies, a structure in which the casting portion 49 is formed in the inner space 45 of the laminated model W is obtained.

<Basic manufacturing procedure of structure>
Next, the basic procedure from forming the laminated model W by the structure manufacturing system 100 and further forming the casting portion 49 to obtain the structure will be described.

First, the controller 15 creates a drive program for modeling the laminated model W by the welding robot 19.

The CAD / CAM unit 31 is input with the shape data of the structure to be manufactured, and generates a shape model of the laminated model W which is the outer shell of the structure according to the shape data of the structure. The shape model generates layer shape data for each bead height obtained by one bead formation.

That is, layer shape data representing the cross-sectional shape of the shape model in each layer for each height from the base 41 is analytically obtained from the shape data and generated. The layer shape data of each generated layer is sent to the trajectory calculation unit 33.

The trajectory calculation unit 33 calculates the movement trajectory of the torch 17 according to the input layer shape data. The movement locus is obtained as coordinate data or vector data including, for example, a start point, an end point, and a movement path from the start point to the end point. The trajectory calculation unit 33 generates a drive program for the welding robot 19 for moving the torch 17 along the movement trajectory obtained from each layer shape data, and stores it in the storage unit 35.

(Outer shell modeling process)
The control unit 37 drives the welding robot 19 based on the generated drive program.
The control unit 37 drives the welding robot 19 to move the torch 17 along the movement locus of the first layer, and forms the bead 43 of the first layer on the base 41. Subsequently, the torch 17 is moved along the movement locus of the second layer to form the bead 43 of the second layer. This operation is repeated to finally form the bead 43 of the nth layer. As a result, the laminated model W (hereinafter referred to as an outer shell) is modeled.

(Reinforcing member joining process)
Next, although details will be described later, a reinforcing member prepared separately from the outer shell W is welded to the outer shell W.

(Casting process)
Next, the crucible 27 is moved to the position of the outer shell W by a pouring mechanism (not shown), and the casting water 25 is poured into the inner space 45 of the outer shell W via the sprue 46 and the runner 47. In FIG. 1, the schematic shapes of the sprue 46 and the sprue 47 are shown in a simplified manner, but the actual sprue 46 and the sprue 47 are formed by a casting mold. Then, the casting water 25 poured into the inner space 45 of the outer shell W is solidified to form the casting portion 49.

This casting process may be performed manually without using the controller 15. Then, if necessary, the base 41 is cut off with a cutting machine such as a wire saw or a diamond cutter.

Through the above steps, a structure including an outer shell W on which a linear bead layer is laminated, a reinforcing member joined to the outer shell W, and a casting portion 49 provided in the inner space of the outer shell W. 51 is obtained.

As the base 41, a plate material having the same outer edge shape as the shape of the movement locus of the first layer may be used, and the bead 43 of the first layer may be formed along the outer edge of the base 41. In that case, since the base 41 hardly protrudes from the outer shell W, the step of separating the base 41 can be omitted.

Further, the separation of the base 41 from the outer shell W may be a step of separating the bead 43 of the second and third layers which is in the vicinity of the base 41, instead of the interface with the base 41. In the vicinity of the base 41, the heat removal effect from the base 41 is high, so that the residual stress tends to be large. On the other hand, in the beads 43 of the third and subsequent layers, the residual stress is relaxed by annealing by laminating the next layer. Therefore, by separating the beads 43 having several layers in the vicinity of the base 41, it is not necessary to be aware of the influence of the residual stress.

The above-mentioned laminated molding of the bead 43 is an example of laminating in an annular shape in each layer, but it may be continuously laminated in a spiral shape. That is, by forming the end point of the bead 43 in the front layer and the start point of the bead 43 in the next layer in succession, the bead 43 can be continuously formed without stopping the torch 17. According to this, the tact time can be shortened, and the outer shell W can be formed with a homogeneous bead 43.

According to the above-mentioned molding step of the outer shell W and the casting step of the casting portion, the outer shell W of the structure 51 is laminated and molded by the bead 43, and the inner space 45 of the outer shell W is filled with the casting portion. Therefore, the number of steps required for the laminated molding can be significantly reduced as compared with the case where the entire structure 51 is laminated. Further, by laminating the outer shell W, it is possible to eliminate the cost of the casting mold manufacturing process and the cost for it. Therefore, the casting process can be simplified and the lead time for manufacturing the structure can be shortened.

Since the outer shell W can be formed into an arbitrary shape by laminating the beads 43, the degree of freedom in designing the shape of the structure is improved. Therefore, even a structure having a complicated shape, which makes the production of a mold complicated when the structure is produced only by casting, can be easily produced. For example, even if the structure has a hollow shape having a different shape in the height direction, an overhang, or the like, it can be easily modeled. Further, even if there is a narrow portion in the inner space 45 of the outer shell W, if the casting water 25 can flow, the inner space 45 can be filled with the casting water 25 without a gap, and the casting portion as intended can be obtained. It can be formed reliably.

Further, since the uneven shape of each layer is formed on the surface of the outer shell W formed by the bead 43, the joint strength between the cast portion and the outer shell W is improved, and the mechanical strength of the structure itself is increased. Be done.

Then, by casting a material cheaper than the laminated material (filler M) into the inner space 45 of the outer shell W, the relatively expensive laminated material can be used only by the outer shell W. Therefore, the material cost can be suppressed and the manufacturing cost can be reduced as compared with the case where all of the structure 51 is manufactured of the laminated material.

Next, a reinforcing member of the structure manufactured by the above-mentioned method for manufacturing the structure will be described as a specific example.
<First configuration example>
FIG. 2 is a perspective view of the structure 51 of the first configuration example.
The structure 51 having this configuration has a hollow outer shell W having a rectangular cross section, and a casting portion 49 solidified by pouring casting water into the inner space 45 of the outer shell W. In the drawings described below, a state in which the base 41 shown in FIG. 1 is omitted or a part thereof is omitted is shown.

The outer shell W shown in FIG. 2 has a first wall portion 53A and a second wall portion 53B facing each other. A pair of ribs 61 as reinforcing members are welded to the outside of the first wall portion 53A and the second wall portion 33B, respectively. In FIG. 2, a pair of ribs 62 are provided on the first wall portion 53A, but the number of ribs 61 installed may be one or three or more.

The rib 61 is a plate-shaped metal block material (bulk material) extending in one direction. The rib 61 is provided along the longitudinal direction along the forming direction D1 of the bead 43, which is the longitudinal direction of the first wall portion 53A, and the lateral direction is projected outward from the first wall portion 53A. The pair of ribs 61 are provided between one end and the other end of the first wall portion 53 in the longitudinal direction in parallel with each other and separated from each other. Further, at least one rib is welded to the second wall portion 53B in the same manner as the first wall portion 53A. The rib 61 may be formed on at least one wall portion (first wall portion 53A).

The material of the rib 61 is preferably a steel material having a linear expansion coefficient close to that of the bead 43 and having excellent weldability and load bearing capacity. Further, the present invention is not limited to this, and other metal materials, ceramics, and the like may be used. When the rib 61 is ceramic, it can be joined to the outer shell W by brazing or the like.

The rib 61 may be continuously formed in the longitudinal direction, or may be divided into a plurality of ribs 61 on a straight line. Further, the arrangement position of the rib 61 is parallel to the pair of facing sides in the rectangular first wall portion 53A (second wall portion 53B), and between one end and the other end of the pair of facing sides. , May be arranged at equal intervals from each opposite side. Further, they may be arranged in a rectangular diagonal direction. Then, the plurality of ribs 61 may be arranged so as to intersect each other like a "+" shape or an "x" shape, or may be arranged in an annular shape such as a rectangle, a polygon, a circle, or an ellipse. In that case, the outer shell W can be configured to have a high strength regardless of the deformation direction thereof, and the deformation of the outer shell W due to heating or heat shrinkage can be efficiently suppressed.

3A and 3B are process explanatory views showing a procedure for forming the outer shell W and the rib 61 of the structure 51 shown in FIG.
As shown in FIG. 3A, the outer shell W of the structure 51 is laminated by the welding robot 19 shown in FIG. 1 by sequentially laminating the beads 43 on the base 14.

Then, as shown in FIG. 3B, the welding robot 19 welds the rib 61 to the laminated outer shell W. In this case, by welding the rib 61 with the welding robot 19 used for the laminated molding of the outer shell W, it is possible to reduce the increase in equipment and man-hours.

Next, the casting apparatus 13 pours the casting water 25 into the inner space 45 of the outer shell W to solidify it, and forms the casting portion 49. The casting water 25 is poured into the inner space 45 from the lower side of the outer shell W shown in FIG. 2 as shown by an arrow HM. As a result, a structure 51 in which the casting portion 49 is integrally formed inside the outer shell W is obtained.

FIG. 4 is a sectional view taken along the line AA of the structure 51 shown in FIG. 2 after solidification of the casting water in the inner space of the outer shell W, and FIG. 5 is a reference view corresponding to FIG. 4 when no reinforcing member is provided. be.
As shown in FIG. 4, in the outer shell W to which the rib 61 is joined, the first wall portion 53A and the second wall portion 53B are in a direction in which the first wall portion 53A and the second wall portion 53B approach each other due to heat shrinkage (arrow Pa) due to solidification of the casting water. Stress is generated in. However, since the first wall portion 53A and the second wall portion 53B are reinforced by the rib 61, deformation of each wall portion is suppressed.

On the other hand, as shown in FIG. 5, when the rib 61 which is a reinforcing member is not provided on the outer shell W, the outer shell W is greatly deformed inward due to the heat shrinkage (arrow Pa) of the casting water. .. Further, if a temporary thermal deformation occurs in the outer shell W during pouring and the casting solidifies while the deformation returns to the original shape after cooling, the cast portion 49 and the outer shell W after cooling are formed. A gap 60 is likely to occur between the inner surface and the inner surface of the.

As described above, according to the structure 51 having the present configuration, the residual deformation after cooling can be suppressed by the reinforcing effect of the rib 61, and the deviation from the design dimensions can be reduced. Further, since the deformation of the outer shell W is suppressed, the amount of elastic deformation of the outer shell W is small even when the casting water solidifies before the outer shell W, and a gap is generated between the outer shell W and the casting portion 49. It becomes difficult. Thereby, the product quality of the structure 51 can be improved.

Further, since the rib 61 is provided so as to project to the outside of the structure 51, another member can be provided on the rib 61 by welding, fastening, or the like, and the degree of freedom in designing the structure 51 can be improved.

Here, the outer shell W shown in FIGS. 2 to 4 is formed by a bead 43 in which the first wall portion 53A, the second wall portion 53B, and the side wall 55 are continuous. On the other hand, as shown in FIG. 6, when the structure 51A is formed in an annular shape, the inner first wall portion 53A of the structure 51A becomes the inner wall, and the outer second wall portion 53B becomes the outer wall. , The side wall 55 is omitted. Even in that case, by providing one or a plurality of ribs 61 on at least one of the first wall portion 53A and the second wall portion 53B, each wall portion can be reinforced and deformation of the outer shell W can be suppressed.

According to the annular structure 51A, the hollow shape in which a space is formed in the central portion makes it possible to reduce the weight of the structure 51A with respect to the size of the outer shape. Further, the shape of the structure 51A can be variously designed according to the place of use, the purpose of use, and the like, and the application target of the structure 51A can be further expanded.

Further, the rib 61 joined to the outer shell W may be removed after the structure 51 is cooled.

<Second configuration example>
FIG. 7 is a perspective view of the structure 51B of the second configuration example.
The structure 51B having the present configuration is provided with a support member 65 for joining the first wall portion 53A and the second wall portion 53B in the inner space 45 of the outer shell W as a reinforcing member instead of the rib 61 described above. .. Since other configurations are the same as those of the first configuration example, the description thereof will be omitted or simplified by assigning the same reference numerals to the same parts and members.

In FIG. 7, a pair of support members 65 are provided in the inner space 45 of the outer shell W, and each support member 65 is joined to the outer shell W. The number of the support members 65 installed may be one or three or more. As the number of support members 65 installed increases, the generated stress is dispersed and stress concentration becomes less likely to occur.

The support member 65 may be a member that can connect the first wall portion 53A and the second wall portion 53B and support a force from each wall portion in the direction of approaching each other. The shape of the support member 65 is not particularly limited, but may be a plate-shaped body or a rod-shaped body extending in one direction. As will be described in detail later, the support member 65 is welded to the first wall portion 53A and the second wall portion 53B, and then cast and wrapped with hot water.

As the support material 65, a metal block material (bulk material) such as a steel material having a linear expansion coefficient close to that of the bead 43 and having excellent weldability and load bearing capacity can be used. Further, the present invention is not limited to this, and other metal materials, ceramics, and the like may be used.

In the configuration shown in FIG. 7, the support members 65 are arranged in pairs at the center of the horizontal width of the rectangular first wall portion 53A and the second wall portion 53B, apart from each other in the vertical direction. The pair of support members 65 are provided in a straight line parallel to each other and separated from each other. The arrangement form of the support member 65 is not limited to this, and may be, for example, a form arranged along the diagonal direction or a form arranged regularly or randomly.

8 (A), (B), and (C) are process explanatory views showing a procedure for forming the outer shell W and the support member 65 of the structure 51B shown in FIG. 7. Note that FIG. 8 is a perspective view seen from the back side of FIG. 7.
First, the welding robot 19 shown in FIG. 1 moves the torch 17, and as shown in FIG. 8A, the first wall portion 53A is laminated by laminating the beads 43.

Then, as shown in FIG. 8B, the support material 65 is welded to the inner side surface of the laminated molded first wall portion 53A on the second wall portion side by the welding robot 19. The support member 65 may be welded by fillet welding by arc, groove welding, or the like, or laser welding or the like. Further, when the support material 63 is ceramic, it can be joined to the outer shell W by brazing.

Next, as shown in FIG. 8C, the second wall portion 53B is laminated and shaped with the support member 65 sandwiched between the support material 65 and the first wall portion 53A by the welding robot 19. At the same time, the side wall 55 connecting the first wall portion 53A and the second wall portion 53B is also laminated. At this time, the welding robot 19 laminates and forms the second wall portion 53B so that the support member 65 is welded to the second wall portion 53B. As a result, an outer shell W is formed in which the first wall portion 53A and the second wall portion 53B are integrally joined by the support member 65. The bottom of the outer shell W is composed of the base 41 shown in FIG.

Next, the casting water 25 is poured into the inner space 45 of the outer shell W and solidified to form the casting portion 49. The casting water 25 is poured into the inner space 45 from the lower side of the outer shell W shown in FIG. 7 as shown by an arrow HM. As a result, a structure 51B in which the casting portion 49 is integrally formed inside the outer shell W can be obtained.

FIG. 9 is a schematic partial cross-sectional view of the outer shell W in the casting process.
The support member 65 is joined to the outer shell W along the longitudinal direction D2 of FIG. 7 in the vertical direction.

In the casting process, the casting water 25 is poured from below the inner space 45 of the outer shell W. Therefore, the liquid level of the casting water 25 accumulated in the inner space 45 gradually rises from the lower part of the inner space 45, and finally the entire inner space 45 is filled with the casting water 25. Therefore, when the casting water 25 is poured into the inner space 45, the liquid level (liquid level) of the casting water 25 rises and reaches the lower end of the support member 65. After that, the liquid level rises from the lower end to the upper end of the support material 65, and the support material 65 is gradually buried in the casting water 25. At this time, in the case where the support member 65 is provided with a recess for sandwiching the casting water 25, the gas in the inner space 45 accumulates in the recess as the liquid level of the casting water 25 rises, and this gas cannot escape. If a gas pool remains after the casting water 25 is filled, a gap (nest) is formed in the casting portion 49 formed by solidifying the casting water 25.

Therefore, in the structure 51B of the present configuration, the support member 65 faces the longitudinal direction thereof along the liquid level rising direction D3 of the casting water 25 accumulated in the inner space 45 (vertical direction in FIGS. 7 and 8). , Welded to the outer shell W. As a result, when the liquid level of the casting water 25 rises and the support material 65 is buried in the casting water 25, the casting water 25 is filled without creating a gap between the support material 65 and the casting water 25. can.

Therefore, in the longitudinal direction D2 of the support member 65, the angle θ formed with the liquid level rising direction D3 is within ± 60 °, preferably within ± 30 °, more preferably within ± 10 °, and more preferably within ± 5 °. good. Further, it is preferable that the lower surface 65a of the support member 65 is an inclined surface inclined from the horizontal direction.

FIG. 10 is a cross-sectional view taken along the line BB of the structure 51 shown in FIG. 7 after solidification of the casting water in the inner space of the outer shell W.
Similar to the case of the first configuration example, in this configuration as well, due to heat shrinkage (arrow Pa) due to solidification of the casting water, the first wall portion 53A and the second wall portion 53B of the outer shell W are stressed in the direction of approaching each other. Occurs. However, since the space between the first wall portion 53A and the second wall portion 53B is reinforced by the support member 65, deformation of each wall portion is suppressed. As a result, residual deformation after cooling can be suppressed, and deviation from the design dimensions can be reduced. Further, since the deformation of the outer shell W is suppressed, even if the casting water solidifies before the outer shell W, the elastic deformation of the outer shell W is small, and a gap is less likely to occur between the outer shell W and the casting portion 49. Become. Thereby, the product quality of the structure 51B can be improved.

Here, in FIGS. 7 and 8, the outer shell W of the structure 51B is formed by a bead 43 having a first wall portion 53A, a second wall portion 53B, and a side wall 55 continuous with each other. Like the annular structure 51 shown in 6, the inner first wall portion 53A may be formed as an inner wall, and the outer second wall portion 53B may be formed as an outer wall.

<Third configuration example>
FIG. 11 is a cross-sectional view corresponding to FIGS. 4 and 10 of the structure 51C of the third configuration example.
The structure 51C having the present configuration includes both the rib 61 of the first configuration example and the support member 65 of the second configuration example described above.

According to the structure 51C having this configuration, the deformation of the outer shell W due to the solidification of the casting water is further suppressed by the synergistic reinforcing effect of the rib 61 and the support material 65, and the product quality can be further improved.

<Other configuration examples>
In the above structures 51, 51A and 51B, the entire outer shell W is composed of an annular bead 43 formed by laminated molding, but the present invention is not limited to this.
FIG. 12 is a schematic partial cross-sectional view showing another configuration example of the structure.
In the structure 51D, a part of the outer shell W (second wall portion 53B in FIG. 12) is composed of the wall surface 71a of the rigid member 71 instead of the laminated body of the beads. That is, the bead constituting the outer shell W is connected to the wall surface 71a of the rigid member 71, and the region surrounded by the outer shell W and the wall surface 71a of the rigid member 71 becomes the inner space 45 of the outer shell W. ing. The rigid member 71 may be a member different from the outer shell W, such as a metal block such as a steel material or a wall portion of another structure, and may be a material that can be welded to the outer shell W.

In the inner space 45, a casting portion 49 filled with casting water is formed. Although not shown, the structure 51D of the present configuration is provided with at least one of the rib 61 (see FIG. 2) of the first configuration example and the support member 63 (see FIG. 7) of the second configuration example. ..

According to the structure 51D of this configuration, since a part of the outer shell W is composed of the rigid member 71, the rigidity of the outer shell W connected to the outer shell W is improved, and the thermal deformation due to heating and the solidification of the cast water are solidified. Distortion due to heat shrinkage is less likely to occur. As a result, the deviation of the structure 51D from the design dimensions is reduced, and the generation of a gap between the outer shell W and the casting portion 49 is suppressed.

The present invention is not limited to the above-described embodiment, and can be modified or applied by those skilled in the art based on the mutual combination of the configurations of the embodiments, the description of the specification, and the well-known technique. The invention is planned and is included in the scope for which protection is sought.

Further, in the above manufacturing method, the welding wire is melted by arc discharge to form a bead, and the structure can be laminated and formed with high energy efficiency and low cost. The bead may employ a heating method in which an arc discharge and a laser are used in combination. In that case, the amount of heating can be controlled more finely, the state of the bead can be maintained more appropriately, and the quality of the laminated model can be further improved.

Further, although the above description shows the configuration in which the beads are formed into one closed linear layer, the closed lines due to the beads may be present at a plurality of places. Further, in the closed linear layer, there may be a bead portion that extends further to the outside or inside of the line due to the bead. In either case, a structure having a more complicated shape can be produced by pouring casting water into each of the closed regions. The closed area in this case is not limited to a rectangle, but may be any shape such as a square, a triangle, another polygon, a circle, or an ellipse.

Further, in the above explanation, a laminated model body that becomes an outer shell is formed by a single linear bead, but a bead is formed while swinging the torch like a weaving operation, or a circle, a triangle, or the like. You may move the torch while drawing the trajectory of. In that case, the bead width can be increased to arbitrarily adjust the thickness of the outer shell, the inner shell, and the like.

In each structure, the bottom of the outer shell is formed by the base, but the structure is not limited to this. For example, the bottom of the outer shell may be formed separately from the base by repeatedly forming the beads in the direction away from the base, starting from the bead formed on the base.

As described above, the following matters are disclosed in this specification.
(1) A method for manufacturing a structure.
A molding process in which beads obtained by melting and solidifying a filler metal are laminated on a base and the outer shell of the structure is laminated and formed.
The joining process of joining the reinforcing member to the outer shell,
A casting process in which casting water is poured into the inner space of the outer shell to form a casting portion inside the outer shell.
A method for manufacturing a structure having a structure.
According to this structure manufacturing method, it is not necessary to manufacture a wooden mold or the like for forming the outer shell of the structure, the mold manufacturing process and cost can be reduced, the lead time can be shortened, and the manufacturing cost can be reduced. .. Further, the reinforcing member that reinforces the outer shell suppresses thermal deformation of the outer shell that occurs during and after pouring the casting portion, and can reduce deviation from the design dimensions after cooling. Further, since the deformation of the outer shell is suppressed, the amount of elastic deformation of the outer shell is small even when the cast water solidifies before the thermal deformation of the outer shell returns by cooling. Therefore, after cooling, a gap is less likely to occur between the outer shell and the cast portion, and the product quality of the structure is improved.

(2) The reinforcing member is a plate-shaped body or a rod-shaped body extending in at least one direction, which is separate from the outer shell.
The method for manufacturing a structure according to (1), wherein the joining step includes a step of welding the reinforcing member to the outside of the outer shell with the longitudinal direction of the reinforcing member along the outer shell.
According to the method for manufacturing this structure, the deformation of the outer shell due to the shrinkage of the casting water can be suppressed by the reinforcing member on the outside of the outer shell.

(3) The method for manufacturing a structure according to (1) or (2), wherein the joining step includes a step of welding the reinforcing member, which is separate from the outer shell, to the inner space of the outer shell.
According to the method for manufacturing this structure, the deformation of the outer shell due to the shrinkage of the casting water can be suppressed by the reinforcing member inside the outer shell.

(4) The outer shell has a pair of first wall portions and second wall portions facing each other.
The modeling process and the joining process are
The process of laminating and modeling the first wall portion and
A step of welding the reinforcing member to the inner side surface of the first wall portion on the side of the second wall portion.
A step of sandwiching the reinforcing member between the first wall portion and the second wall portion for laminating and modeling.
The method for manufacturing a structure according to (3).
According to the manufacturing method of this structure, the reinforcing member is welded to the first wall portion formed by laminating, and then the second wall portion is laminated and formed, so that the reinforcing member is formed between the first wall portion and the second wall portion. The outer shell can be easily manufactured.

(5) In the casting step, the casting water is poured from below the inner space of the outer shell to form the casting portion.
The reinforcing member is a plate-shaped body or a rod-shaped body extending in at least one direction.
The method according to (3) or (4), wherein in the joining step, the reinforcing member is welded to the outer shell so that the longitudinal direction of the reinforcing member is along the direction in which the liquid level of the casting water accumulated in the inner space rises. How to manufacture the structure.
According to the method for manufacturing this structure, when the casting water is poured into the inner space, the entire reinforcing member can be reliably cast and wrapped without creating a gap between the casting water and the outer surface of the reinforcing member.

(6) The method for manufacturing a structure according to any one of (1) to (5), wherein the reinforcing member is a metal block material.
According to this structure manufacturing method, by forming the reinforcing member with a metal block material different from the bead laminated structure, the manufacturing process can be simplified and the degree of freedom in selecting the material of the reinforcing member can be increased. ..

(7) Any one of (1) to (6), wherein the outer shell is connected to a weldable wall surface, and the inner space is defined by the outer shell and the wall surface connected to the outer shell. The method for manufacturing a structure according to one.
According to the method for manufacturing this structure, the rigidity of the outer shell is improved, and thermal deformation due to heating and thermal shrinkage due to solidification of the cast water are less likely to occur. As a result, the deviation from the design dimensions of the structure is reduced, and the generation of a gap between the outer shell and the casting portion is suppressed.

(8) The method for manufacturing a structure according to any one of (1) to (7), wherein the reinforcing member is provided at a plurality of locations on the outer shell.
According to the method for manufacturing this structure, since the outer shell is reinforced at a plurality of locations, the deformation of the outer shell is reduced more uniformly.

(9) The method for producing a structure according to any one of (1) to (8), wherein the bead is formed by melting the filler metal with an arc.
According to this method for manufacturing a structure, the structure can be laminated and formed with high energy efficiency and low cost.

(10) A laminated body of beads in which the filler metal is melted and solidified, and an outer shell that defines an inner space that is a closed space inside the laminated body.
A reinforcing member joined to the outer shell and made of at least one metal block material,
A casting portion formed in the inner space of the outer shell and
Structure with.
According to this structure, since the structure is composed of an outer shell and a casting part, by casting a material cheaper than the laminated material in the inner space of the outer shell, it is possible to use a relatively expensive laminated material. You only have to do it. Therefore, the material cost can be suppressed and the manufacturing cost can be reduced as compared with the case where the entire structure is manufactured from the laminated material. Further, since the reinforcing member is formed of a metal block material different from the laminated body of the bead, the material of the reinforcing member can be easily changed according to the purpose.

(11) The structure according to (10), wherein the reinforcing member is welded to the outside of the outer shell.
According to this structure, it is possible to have a high-strength structure in which the outer shell is reinforced by the reinforcing member. Further, the degree of freedom in designing the structure can be improved by providing another member in the reinforcing member.

(12) The structure according to (10) or (11), wherein the reinforcing member is welded to the inside of the outer shell.
According to this structure, it is possible to have a high-strength structure in which the outer shell is reinforced by the reinforcing member.

(13) The structure according to any one of (10) to (12), wherein the reinforcing member is provided at a plurality of locations.
According to this structure, by providing a plurality of reinforcing members, the load is dispersed and stress concentration is less likely to occur.

(14) At least a part of the outer shell is joined to a rigid member different from the outer shell, and the casting portion is formed between the outer shell and the rigid member (10) to (13). The structure described in any one of.
According to this structure, since a rigid member having a part of the wall for forming the casting portion different from that of the outer shell is used, the step of laminating and forming the outer shell is reduced, and the rigidity of the outer shell is improved. Therefore, thermal deformation due to heating and thermal shrinkage due to solidification of the cast metal are less likely to occur, deviation from the design dimensions of the structure is reduced, and the generation of a gap between the outer shell and the casting portion is suppressed.

(15) Inside the outer shell, an inner shell in which beads obtained by melting and solidifying the filler metal are laminated and formed is provided.
The outer shell and the inner shell are laminated with a closed linear layer formed by the bead.
The structure according to any one of (10) to (14), wherein the casting portion is formed between the outer shell and the inner shell.
According to this structure, the shape of the structure can be variously set according to the place of use, the purpose of use, and the like, and the application target of the structure can be further expanded.

11 Laminated molding equipment 13 Casting equipment 15 Controller 17 Torch 19 Welding robot 23 Filling material supply unit 25 Metal casting 37 Control unit 41 Base 43 Bead 45 Inner space 49 Casting unit 51, 51A, 51B, 51C, 51D Structure 53A 1st Wall 53B 2nd wall 61 Rib (reinforcing member)
65 Support material (reinforcing member)
71 Rigid member 71a Wall surface W outer shell

Claims (13)

It is a method of manufacturing a structure.
A molding process in which beads obtained by melting and solidifying a filler metal are laminated on a base and the outer shell of the structure is laminated and formed.
The joining process of joining the reinforcing member to the outer shell,
A casting process in which casting water is poured into the inner space of the outer shell to form a casting portion inside the outer shell.
Have,
The joining step is a method for manufacturing a structure including a step of welding the reinforcing member, which is separate from the outer shell, to the inner space of the outer shell . The reinforcing member is a plate-shaped body or a rod-shaped body that extends in at least one direction separately from the outer shell.
The method for manufacturing a structure according to claim 1, wherein the joining step includes a step of welding the reinforcing member to the outside of the outer shell with the longitudinal direction of the reinforcing member along the outer shell. The outer shell has a pair of first wall portions and second wall portions facing each other.
The modeling process and the joining process are
The process of laminating and modeling the first wall portion and
A step of welding the reinforcing member to the inner side surface of the first wall portion on the side of the second wall portion.
A step of sandwiching the reinforcing member between the first wall portion and the second wall portion for laminating and modeling.
2. The method for manufacturing a structure according to claim 2 . In the casting step, the casting water is poured from below the inner space of the outer shell to form the casting portion.
The reinforcing member is a plate-shaped body or a rod-shaped body extending in at least one direction.
The structure according to claim 2 or 3 , wherein in the joining step, the reinforcing member is welded to the outer shell so that the longitudinal direction of the reinforcing member is along the direction in which the liquid level of the casting water accumulated in the inner space rises. How to make a body. The method for manufacturing a structure according to any one of claims 1 to 4 , wherein the reinforcing member is a metal block material. The structure according to any one of claims 1 to 5 , wherein the outer shell is connected to a weldable wall surface, and the inner space is defined by the outer shell and the wall surface connected to the outer shell. How to make a body. The method for manufacturing a structure according to any one of claims 1 to 6 , wherein the reinforcing member is provided at a plurality of locations on the outer shell. The method for manufacturing a structure according to any one of claims 1 to 7 , wherein the bead is formed by melting the filler metal with an arc. A laminated model in which continuous linear layers closed in a plan view are laminated, and an outer shell that defines an inner space that is a closed space inside the laminated model .
A reinforcing member welded to the inside of the outer shell and made of at least one metal block material,
A casting portion formed in the inner space of the outer shell and
Structure with. The structure according to claim 9 , wherein the reinforcing member is welded to the outside of the outer shell. The structure according to claim 9 or 10 , wherein the reinforcing member is provided at a plurality of locations. One of claims 9 to 11 , wherein at least a part of the outer shell is joined to a rigid member different from the outer shell, and the casting portion is formed between the outer shell and the rigid member. The structure described in. Inside the outer shell, an inner shell in which continuous linear layers closed in a plan view are laminated is provided.
The structure according to any one of claims 9 to 12 , wherein the casting portion is formed between the outer shell and the inner shell.

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