JP6765360B2 - Structure manufacturing method and structure - Google Patents

Description

The present invention relates to a method for producing 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 laser, an electron beam, or a heat source such as an arc to melt a metal powder or a metal wire and laminate the molten metal to produce a modeled object.

As a technique for laminating such molten metals to form a modeled object, there is known a technique for producing a mold using a welded bead (see, 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 laminates along contour lines based on the generated shape data, and a obtained laminate. A method for 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 lamination 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 a small amount. .. 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 lamination 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, when casting a part 83 having a protrusion 81 as shown in FIG. 11A, a pressing hot water is applied to a portion such as the protrusion 81 where the shape changes drastically so as not to generate casting defects (shrinkage cavities, gas). Need to be provided. Further, in this state, the protrusion 81 interferes with the mold, and the model (for example, a wooden mold) cannot be removed from the mold. Therefore, it is necessary to devise the shape of the component 83. For example, as shown in FIG. 11B, the front side of the protrusion 81A in the direction V for pulling out the model is formed so as to be continuously connected to the component 83. That is, the protrusion 81A is formed in a wedge shape along the drawing direction V of the model so that it can be pulled out. However, in that case, it is necessary to remove the excess region 85 after casting by an additional step such as cutting.
As described above, in the case of the part 83 having the protrusion 81, the time and cost for installing the pressing hot water at the time of casting increase, and if the part shape cannot be cast as it is, an additional step is required. It ends up.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a structure manufacturing method and a structure capable of shortening the lead time when manufacturing the structure and reducing the manufacturing cost. To do.

The present invention has the following configuration.
(1) A method for manufacturing a structure.
An outer shell molding process in which a welded bead obtained by melting and solidifying a filler metal using an arc is laminated on a base and the outer shell of the structure is laminated and formed.
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.
(2) An outer shell on which weld beads, which are melt-solidified bodies of filler metal, are laminated, and
The casting part formed inside the outer shell and
Structure with.

According to the present invention, it is possible to shorten the lead time when manufacturing the structure and reduce the manufacturing cost.

It is a schematic block diagram which shows typically the manufacturing system of the structure of this invention. It is explanatory drawing which shows the shape model based on the shape data of a laminated model | body. It is a process explanatory drawing which shows the procedure of laminating molding of a structure step by step. It is a process explanatory drawing which shows the procedure of laminating molding of a structure step by step. It is a process explanatory drawing which shows the procedure of laminating molding of a structure step by step. It is a process explanatory drawing which shows the procedure of laminating molding of a structure step by step. It is a perspective view of the structure of 1st configuration example. It is a process explanatory drawing which shows the state which moved the torch along the movement locus of the 1st layer on the base plate, and formed the welding bead of the 1st layer. It is a perspective view of the laminated model body having an outer shell, an inner shell, and a partition wall created by the additive manufacturing method. It is a partial perspective view which shows only the partition wall of the laminated model shown in FIG. FIG. 5 is an enlarged cross-sectional view showing a casting portion in which casting hot water flows into the communication hole of the partition wall and is integrated on both the front and back surfaces of the partition wall. It is a perspective view of the structure of the 3rd configuration example. It is a perspective view which shows a part of the structure of 4th structural example. It is a schematic explanatory drawing which shows the conventional part which has a protrusion. It is a schematic explanatory drawing of the conventional part which made the protrusion part come out from a mold.

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 casting is performed inside the outer shell. Manufactured by forming a portion.

FIG. 1 is a schematic configuration diagram schematically showing a manufacturing system for the structure of the present invention.
The manufacturing system 100 having this configuration 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 includes a welding robot 19 having a torch 17 on a tip shaft, and a filler material supply unit 23 that supplies a filler metal (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 molding device 11 and the casting device 13, existing devices are used in this configuration.

The controller 15 includes 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 freedom of the robot arm.

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 laminated model W to be manufactured. Will be done.

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 metal M in a shield gas atmosphere while holding the filler metal M. The filler metal M is fed from the filler metal supply unit 23 to the torch 17 by a feeding mechanism (not shown) attached to a robot arm or the like. Then, when the filler metal M that is continuously fed is melted and solidified while moving the torch 17, a linear weld bead 43 that is a molten solidified body of the filler metal M is formed on the base plate 41.

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.

In the manufacturing system 100 of the structure having this configuration, the above-mentioned laminated model W is modeled on the base plate 41 by the laminated modeling device 11. That is, the welded bead 43 obtained by melting and solidifying the filler metal M is formed into a linear shape closed in a plan view on the base plate 41. By sequentially laminating the welded beads 43, the welded beads 43 are formed into a closed linear layer in a continuous state without gaps, and the linear layers are laminated in the vertical direction without gaps. , The bottomed tubular laminated model W is modeled. The base plate 41 is made of a metal plate such as a steel plate, and is basically a base plate 41 larger than the bottom surface (bottom layer surface) of the laminated model W. The base plate 41 is not limited to a plate shape, and may be a base having another shape such as a block body or a rod shape.

Then, 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 47 is formed in the inner space 45 of the laminated model W is obtained.

Next, a specific procedure from forming the laminated model W by the manufacturing system 100 having the present configuration and further forming the cast portion 47 to obtain the structure will be described in detail.

FIG. 2 is an explanatory diagram showing a shape model Wa based on the shape data of the laminated model W.
First, the controller 15 creates a drive program for modeling the laminated model W by the welding robot 19.

The shape data of the structure to be manufactured is input to the CAD / CAM unit 31. The CAD / CAM unit 31 generates a shape model Wa of the laminated model W which is the outer shell of the structure from the shape data of the structure. Then, the height of one layer obtained by forming the welding bead once by the laminated modeling apparatus 11 is defined as H, and the layer shape data 49 for each height H of the shape model Wa is generated.

That is, the layer shape data 49 representing the cross-sectional shape of the shape model Wa in the layer P (1) having a height H from the base plate 41 is analytically obtained from the shape data of the shape model Wa and generated. Similarly, the layer shape data 49 is generated from the layer P (2) having a height of 2H, the layer P (3) having a height of 3H, and the layer P (n) having a height of nH. The generated layer shape data 49 of the layers P (1) to P (n) are sent to the orbit calculation unit 33 shown in FIG.

The trajectory calculation unit 33 calculates the movement trajectories T (1) to T (n) of the torch 17 based on the input layer shape data 49. The movement loci T (1) to T (n) are 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 that moves the torch 17 along the movement trajectory obtained from each layer shape data 49. The generated drive program is stored in the storage unit 35.

That is, the trajectory calculation unit 33 obtains the movement loci T (1) to T (n) from the layer shape data 49 of the plurality of layers P (1) to P (n) parallel to each other and at equal intervals. Then, the trajectory calculation unit 33 generates a drive program for the welding robot 19 that moves the torch 17 along each movement trajectory T (1) to T (n).

Next, the control unit 37 drives the welding robot 19 based on the generated drive program.
3A to 3D are process explanatory views showing a stepwise procedure for laminating and modeling a structure.
The welding robot 19 shown in FIG. 1 moves the torch 17 shown in FIG. 3A along the movement locus T (1) shown in FIG. 2 to form the welding bead 43 of the first layer on the base plate 41. Subsequently, the welding robot 19 moves the torch 17 along the movement locus T (2) to form the welding bead 43 of the second layer, and finally the welding of the nth layer as shown in FIG. 3B. Form the bead 43. As a result, the laminated model W is modeled (outer shell modeling process).

Next, the crucible 27 shown in FIG. 1 is moved to the position of the laminated model W by a pouring mechanism (not shown), and the casting water 25 is poured into the inner space 45 of the laminated model W. This step may be performed manually without relying on the controller 15.

Then, as shown in FIG. 3C, the casting water poured into the inner space 45 of the laminated model W is solidified to form the casting portion 47 (casting step). Then, if necessary, the base plate 41 is separated as shown in FIG. 3D (base plate cutting step). Through the above steps, a structure 51 including an outer shell on which linear welded bead layers are laminated and a casting portion 47 provided in the inner space of the outer shell is obtained.

As the base plate 41, a plate material having the same outer edge shape as the shape of the movement locus T (1) of the first layer may be used, and the welded bead 43 of the first layer may be formed along the outer edge of the base plate. In that case, since the base plate 41 hardly protrudes from the structure 51, the step of separating the base plate 41 can be omitted.

The step of separating the base plate 41 from the laminated model W may be a step of separating the base plate 41 by including a few layers of welded beads 43 in the vicinity of the base plate 41 instead of the interface with the base plate 41. In the vicinity of the base plate 41, the effect of removing heat from the base plate 41 is high, so that the residual stress tends to increase. On the other hand, in the welded beads 43 of the third and subsequent layers, the residual stress is relaxed by annealing by laminating the next layer. Therefore, it is not necessary to be aware of the influence of the residual stress by separating the welding beads 43 of several layers in the vicinity of the base plate 41.

Further, the laminated model W shown in FIGS. 3A to 3D is an example of laminating the welded beads 43 in a circular shape, but may be continuously laminated in a spiral shape. That is, by forming the end point of the welded bead 43 of the front layer and the start end point of the welded bead 43 of the next layer in succession, the welded bead 43 can be continuously formed without stopping the torch. According to this, the tact time can be shortened, and the laminated model W can be modeled with the homogeneous welded bead 43.

According to the above step, only the outer shell of the structure 51 is laminated and molded with the weld bead 43, and the inner space 45 of the outer shell is filled with the casting portion 47. Therefore, the number of steps required for the laminated modeling can be significantly reduced as compared with the case where the entire structure 51 is laminated. Further, by laminating the outer shell, it is possible to eliminate 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.

Further, since the outer shell can be formed into an arbitrary shape by laminating the welded beads 43, the degree of freedom in designing the shape of the structure 51 is improved. Therefore, when the structure is manufactured by casting, the structure can be easily manufactured even if the structure has a complicated shape, which makes the molding of the mold complicated. For example, even if the laminated model W has a hollow shape or an overhang whose shape differs in the height direction, it can be easily modeled. Further, even if there is a narrow portion in the inner space of the laminated model W, if the casting hot water can flow, the casting hot water can be filled in the inner space 45 without a gap, and the casting portion 47 as intended is surely formed. Can be formed.

Further, since the uneven shape of each layer is formed on the surface of the outer shell formed by the welded bead 43, the joint strength between the cast portion 47 and the outer shell is improved, and the mechanical strength of the structure 51 itself is increased. Can be enhanced.

Then, by casting a material cheaper than the laminated material (additive material M) into the inner space 45 of the laminated model W, the relatively expensive laminated material can be used only by the laminated model 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 specific example of the structure produced by the above-mentioned method for producing the structure will be described.
<First configuration example>
FIG. 4 is a perspective view of the structure of the first configuration example.
The structure 51A having this configuration is a hollow casing used as an outer cylinder of the gear pump. This structure 51A has a laminated shaped body W _A, and a casting portion 47A which solidified by pouring Soleil the inner space 45 of the laminated shaped body W _A.

Laminated shaped body W _A includes an outer shell 55 of the cross section elliptical forming the skeleton of the outer cylinder of the gear pump, and inner shell 57 formed inside the outer shell 55. The inner shell 57 has a shape in which two cylindrical bodies are arranged closer to each other than the radial distance and connected as one inner wall portion. A pump rotor is inserted into each of the hollow spaces defined in the pair of partially cylindrical inner wall portions, and the inner side surface of the inner wall portion serves as the facing surface of the rotor.

Further laminated shaped body W _A has a partition wall 59 which divides the space between the inner shell 57 and outer shell 55 into a plurality of blocks. The partition wall 59 may be continuous in the vertical direction (height direction) shown in FIG. 4, or may be divided into a plurality of partitions. Partition wall 59 is to connect the inner shell 57 and outer shell 55, to enhance the strength of the laminate shaped body W _A.

The structure 51A having the above configuration is manufactured by the procedure shown in FIGS. 3A to 3D described above. That is, the CAD / CAM unit 31 shown in FIG. 1 has the shape data of the structure 51A, and based on this shape data, the layers P (1) and P (2) divided in parallel with each other shown in FIG. , ..., P (n) layer shape data is generated. Then, the trajectory calculation unit 33 determines the movement loci T (1), T (see FIG. 1) of the torch 17 (see FIG. 1) in each layer P (1), P (2), ..., P (n) based on each layer shape data. 2), ..., T (n) is generated, and a drive program for the welding robot 19 is generated. Then, the control unit 37 drives the welding robot 19 based on the generated drive program.

FIG. 5 is a process explanatory view showing a state in which the torch 17 is moved on the base plate 41 along the movement locus T (1) of the first layer to form the welded bead 43 of the first layer.
In this case, the filler metal M and the base plate 41 are melted by an arc, and the filler metal M is raised and arranged on the base plate 41. The first layer to be the outer shell 55, the inner shell 57, and the partition wall 59 on the base plate 41 is formed in an appropriate order obtained by the orbit calculation unit 33.

As the movement locus, it is preferable to make the path for forming the welded bead 43 continuous, because the welded bead 43 tends to be homogeneous and the formation time per layer can be shortened, from the viewpoint of production efficiency. In the case of this example, the welding bead 43 of the first layer is a combination of the path forming the outer shell 55 in the first layer, the path forming the inner shell 57, and the path forming the plurality of partition walls 59. Can be formed. In addition to the above order, a method of forming the weld bead 43 may be adopted so that the number of passes is as small as possible.

Subsequently, in the same manner, the torch 17 is moved along the movement loci T (2), ..., T (n), and the welding beads of the plurality of layers P (1), P (2), ..., P (n) are welded. 43 are sequentially laminated. As a result, the outer shell 55 shown in FIG. 6, the inner shell 57 arranged inside the outer shell 55, and the partition wall 59 arranged between the outer shell 55 and the inner shell 57 are laminated as described above. _A laminated model WA can be obtained by the outer shell modeling process, the inner shell modeling process, and the partition wall modeling process.

Then, as shown in FIG. 4, the inner space 45 defined by an outer shell 55 of laminated shaped body W _A and the inner shell 57 and the partition wall 59, it is coagulated by pouring Soleil 25, a casting portion 47A Form. Further, the base plate 41 shown in FIG. 6 is cut by a cutting machine such as a wire saw or a diamond cutter. As a result, the structure 51A having a desired shape can be obtained.

According to the structure 51A of this configuration, since the laminated shaped body W _A is formed by lamination of the weld bead 43, the type prepared for casting is not necessary, it is possible to reduce the cost of the casting steps and mold material, structure The lead time for manufacturing the body 51A is shortened. Further, the use of a relatively expensive laminated material is only required for the outer shell 55, the inner shell 57, and the partition wall 59, and the material cost can be suppressed and the manufacturing cost can be reduced.

<Second configuration example>
FIG. 7 is a partial perspective view showing only the partition wall of the laminated model shown in FIG.
The partition wall 59A of the laminated model of the present configuration has a plurality of communication holes 61. Other configurations are the same as those of the first configuration example. The communication holes 61 are preferably arranged at equal intervals along the longitudinal direction of the partition wall 59A. By forming the communication hole 61 in the partition wall 59A in this way, when the casting water is poured into the inner space of the laminated model, the casting water flows into the communication hole 61 as shown in FIG. 8, and the partition wall 59A A casting portion 47A in which both the front and back surfaces are integrated is formed. According to this, the joint strength between the partition wall 59A connected to the outer shell 55 and the inner shell 57 and the casting portion 47A is further improved, and the strength of the structure can be improved.

It is preferable that the communication hole 61 is formed at the same time as the molding of the laminated model. Further, the present invention is not limited to this, and if a tool such as a drill can be inserted, it may be formed by machining after modeling. Further, a plate material provided with communication holes in advance may be joined to the outer shell 55 and the inner shell 57. In that case, the calculation of the movement locus and the complexity of the torch movement are reduced.

Further, since the communication hole 61 is formed in the partition wall 59A, when the casting water is poured between the outer shell 55 and the inner shell 57, it is divided by the partition wall 59A through the communication hole 61 of the partition wall 59A. Casting water flows into multiple inner spaces in sequence. Therefore, even if the hot water supply position is fixed, the casting hot water can be evenly supplied to each inner space defined by the outer shell 55, the inner shell 57, and the partition wall 59A, and the configuration of the casting apparatus 13 can be simplified.

<Third configuration example>
FIG. 9 is a perspective view of the structure of the third configuration example.
The structure 51B having this configuration is a configuration example in which the casing shown in the first configuration example is a cooling jacket in which a cooling cavity portion is formed.

The structure 51B has a stacked shaped body W _B, the outer shell 55 described above, the inner shell 57, and a partition wall 59, further, formed in the space between the inner shell 57 and outer shell 55 , A cooling pipeline 65 for flowing a cooling medium is provided. The cooling pipeline 65 is composed of a pair of continuous partition walls 59A and 59B, and is formed by laminating weld beads in the same manner as the outer shell 55, the inner shell 57, and the partition wall 59.

Of the inner space 45 defined by an outer shell 55 of laminated shaped body W _B and inner shell 57 and the partition wall 59 and the cooling pipe 65, the inner space other than the cooling pipe 65, Soleil 25 Is poured and solidified. As a result, the casting portion 47B is formed between the outer shell 55 and the inner shell 57, leaving the cooling pipeline 65.

A hollow portion (inside the cooling conduit 65) can be easily formed by providing a portion where the casting water 25 is poured and a portion where the casting water 25 is not poured into the defined inner space 45 as in the structure 51B of the present configuration.

<Fourth configuration example>
FIG. 10 is a perspective view showing a part of the structure of the fourth configuration example.
The structure 51C having the present configuration has a protrusion 73 and a flange 75 protruding in a direction intersecting the laminating direction of the welded beads on a part of the wall portion 71 of the casing of the structure shown in the first to third configuration examples. Is provided.

If the protrusion 73 is present in the structure 51C, the model (wooden mold, etc.) cannot be removed from the mold when it is manufactured by ordinary casting (in the illustrated example, the vertical direction is the drawing direction). Even with such a structure that cannot be cast normally, according to the above-mentioned manufacturing method of the structure, wasteful pressing water for preventing unfilling can be omitted, and additional processing after casting becomes defective. Therefore, the structure 51C can be easily manufactured.

The protrusion 73 is not limited to the cylindrical shape shown in the figure, and any shape can be selected. The protrusions 73 may be arranged at any of the above-mentioned outer shell, inner shell, partition wall, and the like in the structure 51C, and may have a configuration in which a plurality of protrusions 73 are arranged.
Further, the flange portion 75 may be provided at the bottom of the wall portion 71 or at another portion in addition to the configuration provided at the top of the structure 51C.

It should be noted that the structure 51C is difficult to cast normally even if the wall portion 71 is provided with only the protrusion 73, but even in that case, the structure 51C can be easily manufactured by the above-mentioned manufacturing method of the structure. Become.

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 combination of the configurations of the embodiments with each other, the description of the specification, and well-known techniques. It is the planned invention and is included in the scope of seeking protection.

Further, in the above manufacturing method, the welding wire is melted by arc discharge to form a welded bead, and the structure can be manufactured at low cost. The welding 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 welded bead can be maintained more appropriately, and the quality of the laminated model can be further improved.

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

Further, in the above description, the laminated model is formed by one linear welding bead, but the welding bead is formed while swinging the torch like a weaving operation, or by driving the welding robot 19. , The torch may be moved while drawing a locus such as a circle or a triangle. In that case, the weld bead width can be increased to arbitrarily adjust the thickness of the outer shell, inner shell, and partition wall.

As described above, the following matters are disclosed in this specification.
(1) A method for manufacturing a structure.
An outer shell molding process in which a welded bead obtained by melting and solidifying a filler metal using an arc is laminated on a base and the outer shell of the structure is laminated and formed.
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.
According to this method for manufacturing a structure, it is not necessary to manufacture a wooden mold or the like for forming the outer shell of the structure, and the process and cost for manufacturing the mold can be reduced. In addition, the lead time for manufacturing the structure can be significantly shortened, and the manufacturing cost can be reduced.

(2) The structure includes an inner shell formed inside the outer shell.
The base has an inner shell molding step of laminating the welded beads along the shape of the inner shell and laminating the inner shell.
The method for manufacturing a structure according to (1), wherein the casting step is a method of pouring the casting water into the inner space between the outer shell and the inner shell.
According to this method for manufacturing a structure, it is possible to manufacture a hollow structure having an outer shell and an inner shell.

(3) The method for producing a structure according to (2), wherein the outer shell and the inner shell are formed by forming the welded beads into a closed linear shape on the base.
According to the method for producing this structure, the outer shell and the inner shell are formed as a linear layer in which the welding beads are closed, whereby the outer shell and the inner shell having an arbitrary shape can be formed.

(4) The partition wall forming step of laminating the welding beads to form a partition wall arranged between the outer shell and the inner shell and dividing the inner space into a plurality of spaces (2) or ( The method for manufacturing a structure according to 3).
According to the method for manufacturing this structure, a hollow structure having high strength can be manufactured by arranging the partition walls.

(5) The method for manufacturing a structure according to (4), wherein the partition wall has a communication hole for communicating the casting water.
According to this method for manufacturing a structure, the casting water flows into the communication holes, the partition wall and the casting portion are firmly bonded, and the strength of the structure is improved.

(6) The method for producing a structure according to (5), wherein the communication hole is formed by providing a gap during the formation of the welded bead.
According to the method for manufacturing this structure, the communication holes can be easily formed by forming the communication holes at the same time as laminating the welding beads.

(7) Any one of (4) to (6) forming a protrusion protruding in a direction intersecting the stacking direction of the welded beads on at least one of the outer shell, the inner shell, and the partition wall. The method for manufacturing a structure according to.
According to the method for manufacturing this structure, in ordinary casting, even if the structure is such that the protrusions interfere with the mold and the model (wooden mold or the like) cannot be removed, it can be easily formed.

(8) The method for producing a structure according to any one of (1) to (7), which has a base removing step of cutting the base after the casting step.
According to the method for manufacturing this structure, by removing the base, a structure consisting only of a laminated structure of welded beads and a cast portion can be obtained.

(9) An outer shell on which weld beads, which are melt-solidified bodies of filler metal, are laminated, and
The casting part formed inside the outer shell and
Structure with.
According to this structure, since the cast portion is formed inside the outer shell, man-hours and material costs can be reduced as compared with the case where the entire structure is formed by welding beads. In addition, the man-hours and material costs required for mold production can be reduced as compared with the case where the whole is formed by casting.

(10) An inner shell on which the welded beads are laminated is further provided inside the outer shell.
The structure according to (9), wherein the casting portion is formed between the outer shell and the inner shell.
According to this structure, a hollow structure having a casting portion between the outer shell and the inner shell can be easily provided at low cost.

(11) The structure according to (10), which is arranged between the outer shell and the inner shell and includes a partition wall connecting the outer shell and the inner shell.
According to this structure, the partition wall enhances the strength of the structure.

(12) The structure according to (11), wherein any of the outer shell, the inner shell, and the partition wall has a protrusion protruding in a direction intersecting the laminating direction of the welded beads.
According to this structure, in ordinary casting, even if the protrusion interferes with the mold and the model (wooden mold or the like) cannot be removed, it can be easily formed.

(13) The structure according to any one of (10) to (12), wherein the outer shell and the inner shell are formed by laminating closed linear layers formed by the welding beads.
According to this structure, the weld bead is formed as a closed linear layer, which allows the outer and inner shells of any shape to be formed.

25 Casting water 41 Base plate (base)
43 weld bead 45 inside the space 47 and 47A, 47B casting unit 51,51A structure 55 outer shell 57 within shell 59,59A, 59B partition wall 61 communicating hole 73 protrusion M filler _W, W _A, W _B layered manufacturing body

Claims (13)

It is a method of manufacturing a structure.
An outer shell molding process in which a welded bead obtained by melting and solidifying a filler metal using an arc is laminated on a base and the outer shell of the structure is laminated and formed.
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. The structure comprises an inner shell formed inside the outer shell.
The base has an inner shell molding step of laminating the welded beads along the shape of the inner shell and laminating the inner shell.
The method for manufacturing a structure according to claim 1, wherein the casting step is a method of pouring the casting water into the inner space between the outer shell and the inner shell. The method for producing a structure according to claim 2, wherein the outer shell and the inner shell are formed by forming the welded beads into a closed linear shape on the base. According to claim 2 or 3, the partition wall forming step of laminating the welding beads to form the partition wall arranged between the outer shell and the inner shell and dividing the inner space into a plurality of spaces is provided. The method for manufacturing the described structure. The method for manufacturing a structure according to claim 4, wherein the partition wall has a communication hole for communicating the casting water. The method for producing a structure according to claim 5, wherein the communication holes are formed by providing voids during the formation of the welded bead. The invention according to any one of claims 4 to 6, wherein a protrusion is formed on at least one of the outer shell, the inner shell, and the partition wall so as to project in a direction intersecting the laminating direction of the welded beads. How to manufacture the structure. The method for producing a structure according to any one of claims 1 to 7, further comprising a base removing step of cutting the base after the casting step. An outer shell on which weld beads, which are molten solids of the filler metal, are laminated,
The casting part formed inside the outer shell and
Structure with. An inner shell on which the welded beads are laminated is further provided inside the outer shell.
The structure according to claim 9, wherein the casting portion is formed between the outer shell and the inner shell. The structure according to claim 10, further comprising a partition wall arranged between the outer shell and the inner shell and connecting the outer shell and the inner shell. The structure according to claim 11, further comprising a protrusion protruding in a direction intersecting the laminating direction of the welded beads at any of the outer shell, the inner shell, and the partition wall. The structure according to any one of claims 10 to 12, wherein the outer shell and the inner shell are formed by laminating closed linear layers formed by the welding beads.

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