Additive manufacturing system and additive manufacturing method

Abstract

When creating a molded object with a bent section by layering weld beads, the shape of the bent section is smoothed. [Solution] The additive manufacturing system comprises a welding device that melts wire to form a weld bead, and a control device that controls the welding device to create a bent portion of the manufactured object by stacking the weld beads. The control device creates the bent portion by stacking weld beads in the circumferential direction of the bent portion, with the height increasing the further away from the center of curvature of the bent portion.

Description

Technical Field

[0001] The present disclosure relates to a laminated manufacturing system and a laminated manufacturing method for manufacturing a shaped object by stacking welding beads.

Background Art

[0002] Japanese Patent No. 7203671 (Patent Document 1) describes a method for manufacturing a shaped object by stacking welding beads of a certain height in the normal direction of a base material (base plate). In this manufacturing method, when a height difference occurs on the surface of the stacked welding beads, a smoothing bead for eliminating the height difference is added to the surface of the welding beads to smooth the surface of the welding beads.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the object to be shaped has a bent portion, it becomes a problem how to shape the bent portion by stacking welding beads. The manufacturing method disclosed in Japanese Patent No. 7203671 (Patent Document 1) smooths the surface of the welding beads on the premise of stacking welding beads of a certain height in the normal direction of the base material, but nothing is mentioned about how to shape the shape of the bent portion of the object.

[0005] The present disclosure has been made to solve the above problems, and an object thereof is to smooth the shape of a bent portion when shaping a shaped object having a bent portion by laminating welding beads.

Means for Solving the Problems

[0006] The additive manufacturing system according to this disclosure is an additive manufacturing system that creates a molded object having a bent portion by stacking weld beads on a plate-shaped base material, and comprises a welding device that melts wire to form a weld bead, and a control device that controls the welding device to create a bent portion by stacking the weld beads. The control device creates the bent portion by stacking weld beads in the circumferential direction of the bent portion, with the height increasing the further away from the center of curvature of the bent portion.

[0007] The additive manufacturing method according to this disclosure is an additive manufacturing method for manufacturing an object having a bent portion by stacking weld beads on a plate-shaped base material, and includes the steps of acquiring three-dimensional shape data of the bent portion and manufacturing the bent portion by controlling a welding apparatus that forms weld beads based on the shape data. The step of manufacturing the bent portion includes manufacturing the bent portion by stacking weld beads in the circumferential direction of the bent portion, with the height increasing as the distance from the center of curvature of the bent portion increases. [Effects of the Invention]

[0008] According to this disclosure, when creating a molded object having a bent portion by stacking weld beads, the shape of the bent portion can be made smoother. [Brief explanation of the drawing]

[0009] [Figure 1] This diagram schematically shows an example of the configuration of an additive manufacturing system. [Figure 2] This is a block diagram schematically illustrating the control functions of a control device. [Figure 3] This diagram schematically illustrates an example of path generation. [Figure 4] This diagram schematically shows an example of the positioner rotation angles set for each of the five bead layers. [Figure 5] This is a flowchart showing an example of the processing procedure for a control device. [Modes for carrying out the invention]

[0010] The embodiments of this disclosure will be described in detail below with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and their descriptions will not be repeated.

[0011] Figure 1 is a schematic diagram showing an example of the configuration of an additive manufacturing system 1 according to this embodiment. The additive manufacturing system 1 is configured to fabricate an object 100 by stacking welding beads 70 on a plate-shaped base material 80. The additive manufacturing system 1 comprises a welding power supply unit 10, a welding torch 20, a robot arm 40, a wire feeder 50, a positioner 60, and a control device 30. The welding power supply unit 10, the welding torch 20, the robot arm 40, and the wire feeder 50 correspond to an example of a "welding apparatus" in this disclosure.

[0012] The robot arm 40 is a multi-jointed arm, for example, a 6-axis multi-jointed arm. The welding torch 20 is fixed to the tip of the robot arm 40. The robot arm 40 functions as a moving device that moves the welding torch 20 at a set welding speed. As the robot arm 40 moves the welding torch 20, welding beads 70 are piled up, formed by melting and fixing the wire 51. The robot arm 40 is controlled in response to commands from the control device 30 so that the object 100 is formed by the pile of welding beads 70.

[0013] A welding current is supplied to the wire 51 at a power supply tip (not shown) located inside the nozzle 21 of the welding torch 20. The wire 51 is melted by an arc 22 generated between it and the base material 80 or the already layered welding bead 70. The arc 22 melts the wire 51 and the base material 80 or the already layered welding bead 70 simultaneously, forming a molten area (molten pool) 23, and the welding bead 70 is formed when the molten area 23 cools and solidifies. In the following, the vertically upward direction may be referred to as the Z-axis direction, one direction perpendicular to the Z-axis direction (the longitudinal direction of the base material 80 in the example shown in Figure 1) may be referred to as the X-axis direction, and the direction perpendicular to both the Z-axis direction and the X-axis direction may be referred to as the Y-axis direction.

[0014] The welding power supply device 10 supplies a welding current to the wire 51. The welding current may be direct current or alternating current.

[0015] The wire feeding device 50 includes rollers and a motor (not shown). The wire feeding device 50 feeds the wire 51 to the welding torch 20 by driving the motor to rotate the rollers.

[0016] The positioner 60 is a machine for adjusting the posture of the base material 80 to a posture suitable for welding. The rotation angle of the positioner 60 (hereinafter also referred to as "positioner rotation angle A") is controlled according to a command from the control device 30. The positioner rotation angle A corresponds to the inclination angle of the base material 80 with respect to the horizontal plane.

[0017] The control device 30 includes a CPU (Central Processing Unit), a memory, and an input / output port for inputting and outputting various signals (none of which are shown). These elements are connected via a bus.

[0018] The control device 30 controls the robot arm 40, the wire feeding device 50, the welding power supply device 10, and the positioner 60 according to a lamination plan for forming the object 100. Thereby, the welding beads 70 are laminated according to the lamination plan and the object 100 is formed. The control for realizing the function of the control device 30 may be processed by software or may be processed by dedicated hardware (electronic circuit). Although FIG. 1 illustrates a configuration in which a command for the wire feeding device 50 is output from the control device 30, a configuration in which a command for the wire feeding device 50 is output from the welding power supply device 10 instead of the control device 30 may also be used.

[0019] [Forming of the object 100 having a bent portion] In order to form the object 100, which is the final formed product, according to the lamination plan, it is desirable to stabilize the shape of each layer of the welding bead 70. In particular, when the object 100 has a bent portion, it is desirable to make the shape of the bent portion smooth.

[0020] However, for example, when forming a bent portion by stacking welding beads of a certain height in the normal direction of the base material and partially adding another bead to the surface of the stacked welding beads, it is difficult to form another bead that completely eliminates unevenness, so there is a concern that the shape of the bent portion will not become smooth.

[0021] Therefore, when the object 100 has a bent portion, the control device 30 according to the present embodiment does not stack welding beads of a certain height in the normal direction of the base material 80, but stacks welding beads whose height increases as they are farther from the center of curvature of the bent portion in the circumferential direction of the bent portion to form the bent portion.

[0022] FIG. 2 is a block diagram schematically showing the control function of the control device 30 when the control device 30 shapes the object 100. The control device 30 includes a shape data acquisition unit 31, a path generation unit 32, a positioner rotation angle setting unit 33, a database 34, a welding condition setting unit 35, and a lamination command unit 36.

[0023] The shape data acquisition unit 31 communicates with the outside by wire or wirelessly to acquire three-dimensional shape data of the object 100 from the outside.

[0024] Based on the shape data of the object 100, the path generation unit 32 generates a path that is a stacking path of welding beads for shaping the object 100. When the shape data of the object 100 includes a bent portion, the path generation unit 32 generates a path for shaping the bent portion by stacking paths whose height increases as they are farther from the center of curvature of the bent portion in the circumferential direction of the bent portion.

[0025] FIG. 3 is a diagram schematically showing an example of path generation for the bent portion 100a included in the object 100. As the bent portion 100a, for example, a bent portion of a cylindrical pipe is assumed. When the bent portion 100a is a bent portion of a cylindrical pipe, FIG. 3 shows a view of the bent portion of the pipe as seen from the side direction. In addition, in the lower part of FIG. 3, as a comparative example, an example of forming a bent portion by stacking bead layers of a certain height straight along the normal direction of the base material 80 is shown.

[0026] FIG. 3 shows an example of path generation for forming the bent portion 100a by stacking five bead layers 71 to 75. The bead layers 71 to 75 may be formed by a single helical weld bead or may be formed by five separate weld beads. In either case, the bead layers 71 to 75 are stacked on the base material 80 in this order.

[0027] The height of each of the bead layers 71 to 75 is set so as to be higher as it is farther from the center of curvature of the bent portion. By stacking such bead layers 71 to 75 in the circumferential direction of the bent portion, the bent portion 100a is formed. That is, the path generation unit 32 does not stack paths of a certain height straight along the normal direction of the base material 80 (see the comparative example in FIG. 3), but forms a bent portion 100a by stacking bead layers 71 to 75 whose height increases as they are farther from the center of curvature of the bent portion along the circumferential direction of the bent portion. Generate the path to do.

[0028] In addition, when assuming that the radial length of the bead layers 71 to 75 is constant, the shape of each of the bead layers 71 to 75 is the first height h that is the height of the end portion on the inner side (inner circumferential side) of the bend of each bead layer 71 to 75, and the second height H that is the height of the end portion on the outer side (outer circumferential side) of the bend of each bead layer 71 to 75. Therefore, hereinafter, it will be described that the path generation unit 32 generates a path for the bent portion of the object 100 by setting the number of stacked bead layers and the first height h and the second height H of each bead layer. A relationship of h <H holds between the first height h and the second height H of each bead layer.

[0029] Furthermore, the following section will mainly describe the process of fabricating the bent portion 100a, which is formed by the five bead layers 71-75 shown in Figure 3.

[0030] Returning to Figure 2, the positioner rotation angle setting unit 33 sets the positioner rotation angle A for each layer so that melt-through of the molten portion 23 does not occur when forming a weld bead along the path formed by the path generation unit 32.

[0031] Figure 4 schematically shows an example of the positioner rotation angle A set for each of the five bead layers 71 to 75 shown in Figure 3 above. In Figure 4, an example is shown in which the first height h and second height H of the bead layers 71 to 75 are unified to the same predetermined values ​​h1 and H1 for each layer, but the first height h and second height H of the bead layers 71 to 75 may be different for each layer.

[0032] As described above, the heights of the bead layers 71-75 are set to be inclined so that they become higher the further they are from the center of curvature of the bend, and the bead layers 71-75 are stacked in a curved manner along the circumferential direction of the bend. Therefore, if the inclination angle of the base material 80 is kept fixed horizontally, the upper bead layers will be more inclined relative to the horizontal, raising concerns that melting and falling may occur due to the action of gravity.

[0033] Therefore, the positioner rotation angle setting unit 33 sets the positioner rotation angle A (inclination angle of the base material 80) separately for each bead layer 71 to 75 when forming each bead layer 71 to 75, so that the upper surface, lower surface, or intermediate surface between the upper and lower surfaces of each bead layer 71 to 75 is horizontal.

[0034] Figure 4 shows an example of setting the positioner rotation angle A for each bead layer 71-75 so that the upper surface of each bead layer 71-75 is horizontal. Specifically, for the first bead layer 71, the positioner rotation angle A is set to the angle A1 at which the upper surface 71a of the bead layer 71 becomes horizontal when forming the bead layer 71. For the second bead layer 72, the positioner rotation angle A is set to the angle A2 at which the upper surface 72a of the bead layer 72 becomes horizontal when forming the bead layer 72. For the third bead layer 73, the positioner rotation angle A is set to the angle A3 at which the upper surface 73a of the bead layer 73 becomes horizontal when forming the bead layer 73. For the fourth bead layer 74, the positioner rotation angle A is set to the angle A4 at which the upper surface 74a of the bead layer 74 becomes horizontal when forming the bead layer 74. For the fifth bead layer 75, the positioner rotation angle A is set to an angle A5 such that the upper surface 75a of the bead layer 75 becomes horizontal when forming the bead layer 75.

[0035] Returning to Figure 2, the database 34 pre-stores welding condition data for controlling the welding equipment (welding power supply 10, welding torch 20, robot arm 40, and wire feeder 50, etc.) using the first height h, second height H, and positioner rotation angle A of each bead layer as parameters. Note that the welding condition data stored in the database 34 may be obtained by communicating with an external source via wired or wireless connection.

[0036] The welding condition setting unit 35 refers to welding condition data stored in advance in the database 34 and sets welding conditions corresponding to the first height h and second height H of each bead layer set by the path generation unit 32, and the positioner rotation angle A of each bead layer set by the positioner rotation angle setting unit 33.

[0037] The lamination command unit 36 ​​controls the welding equipment (welding power supply unit 10, welding torch 20, robot arm 40, and wire feeder 50, etc.) according to the welding conditions set by the welding condition setting unit 35. As a result, bead layers, which increase in height the further they are from the center of curvature of the bend, are stacked along the circumferential direction of the bend, following the path set by the path generation unit 32, thereby forming the bend 100a. Therefore, compared to the case where the bend 100a is formed by stacking bead layers of a constant height in the direction normal to the base material 80 (see comparative example in Figure 3), it is less likely for irregularities caused by bead ends to occur on the upper surface of the bend 100a, thus making the shape of the bend 100a smoother.

[0038] Furthermore, although multiple bead layers are stacked at an angle relative to the normal direction of the base material 80, the positioner rotation angle A is adjusted so that each bead layer is horizontal when forming it. This makes it easier to suppress the melting and falling of each bead layer due to gravity.

[0039] Figure 5 is a flowchart showing an example of the processing procedure of the control device 30 when it fabricates the object 100.

[0040] First, the control device 30 acquires three-dimensional shape data of the object 100 (step S10).

[0041] Next, the control device 30 generates a path for fabricating the object 100 based on the shape data of the object 100 (step S20). In this case, if the shape data of the object 100 includes a bend, as described above, a path for fabricating the bend is generated by stacking paths in the circumferential direction of the bend, where the height increases the further away from the center of curvature of the bend. In this step S20, as shown in Figure 3 above, the number of bead layers for forming the bend and the first height h and second height H of each bead layer are set.

[0042] Next, the control device 30 sets the positioner rotation angle A for each bead layer set in step S20, as shown in Figure 4 above (step S30).

[0043] Next, the control device 30 refers to the welding condition data stored in the database 34 and sets the welding conditions corresponding to the first height h and second height H of each bead layer set in step S20, and the positioner rotation angle A of each bead layer set in step S30 (step S40).

[0044] Next, the control device 30 shapes the object 100 by controlling the welding apparatus with the welding conditions set in step S40 (step S50).

[0045] As described above, when the object 100 to be fabricated has a bent portion 100a, the control device 30 according to this embodiment fabricates the bent portion by stacking weld beads in the circumferential direction of the bent portion, with the height increasing the further away from the center of curvature of the bent portion 100a (see the present disclosure in Figure 3). As a result, compared to the case where a bead layer of a constant height is stacked in the direction normal to the base material 80 to fabricate the bent portion (see the comparative example in Figure 3), it is less likely for irregularities caused by the bead ends to occur on the upper surface of the bent portion 100a, and thus the shape of the bent portion 100a can be made smoother.

[0046] Furthermore, the control device 30 according to this embodiment adjusts the inclination angle of the base material 80 so that each bead layer is horizontal by controlling the positioner rotation angle A each time a bead layer is formed in the bent portion 100a. This makes it easier to suppress the melting and falling off of each bead layer due to gravity when forming each bead layer in the bent portion 100a. As a result, the shape of the bent portion 100a can be made even smoother.

[0047] [Differentiation] (A) When setting the first height h and second height H of each bead layer, the first height h and second height H of each bead layer may be set higher than expected, taking into account the melting and dripping of the bead.

[0048] (B) Since the height of each bead layer may vary depending on the temperature of the base portion on which each bead layer is stacked, the temperature of the base portion on which each bead layer is stacked may be added to the parameters that define the welding condition data stored in the database 34. For example, when forming each bead layer, the temperature of the base portion may be detected by a thermal camera or the like, and the welding conditions for each bead layer may be modified according to the temperature of the base portion.

[0049] (C) Instead of predetermining the welding conditions for each bead layer, the welding conditions may be set for each layer at the time each bead layer is formed.

[0050] [Aspect] Those skilled in the art will understand that the embodiments and their modifications described above are specific examples of the following embodiments.

[0051] (Section 1) The additive manufacturing system according to the present disclosure is an additive manufacturing system for manufacturing an object having a bent portion by stacking weld beads on a plate-shaped base material, comprising a welding device that melts wire to form a weld bead, and a control device that controls the welding device to manufacture a bent portion by stacking the weld beads. The control device manufactures the bent portion by stacking weld beads in the circumferential direction of the bent portion, with the height increasing the further away from the center of curvature of the bent portion.

[0052] According to the additive manufacturing system of paragraph 1, when creating an object with a bent section, the bent section is created by stacking weld beads in the circumferential direction of the bent section, with the height increasing the further away from the center of curvature of the bent section. As a result, compared to creating a bent section by stacking weld beads of a constant height in the direction normal to the base material, irregularities caused by the bead edges are less likely to occur on the upper surface of the bent section, thus making the shape of the bent section smoother. Consequently, when creating an object with a bent section by stacking weld beads, the shape of the bent section can be made smoother.

[0053] (Section 2) The additive manufacturing system described in Section 1 further comprises a positioner for adjusting the inclination angle of the base material. The control device adjusts the inclination angle of the base material so that the top, bottom, or intermediate surface of each layer is horizontal by controlling the rotation angle of the positioner each time a layer of the weld bead of the bend is formed.

[0054] According to the additive manufacturing system in Section 2, the inclination angle of the base material is adjusted so that either the top, bottom, or middle surface of each bead layer is horizontal by controlling the rotation angle of the positioner each time a layer of weld bead is formed in the bent section. This makes it easier to suppress melt-through due to gravity in each layer when forming the weld bead in the bent section. As a result, the shape of the bent section can be made even smoother.

[0055] (Section 3) In the additive manufacturing system described in Section 2, the control device acquires three-dimensional shape data of the bent portion, sets a first height which is the height of the inner end of the bend and a second height which is the height of the outer end of the bend of each layer based on the acquired shape data, sets the rotation angle of the positioner when forming each layer, and sets welding conditions for forming each layer based on the set first height, second height and rotation angle of the positioner of each layer.

[0056] According to the additive manufacturing system described in Section 3, the height of each layer of the weld bead in the bent section and the rotation angle of the positioner can be appropriately set based on the three-dimensional shape data of the bent section, and the welding conditions for each layer of the weld bead in the bent section can be appropriately set.

[0057] (Section 4) In the additive manufacturing system described in Section 3, the control device pre-stores welding condition data with the first height, second height, and positioner rotation angle of each layer as parameters. The control device refers to the pre-stored welding condition data and sets the welding conditions corresponding to the set first height, second height, and positioner rotation angle of each layer.

[0058] According to the additive manufacturing system described in Section 4, the welding conditions for each layer of the weld bead in the bent section can be appropriately set by referring to pre-stored welding condition data.

[0059] (Section 5) The additive manufacturing method according to the present disclosure is an additive manufacturing method for manufacturing an object having a bent portion by stacking weld beads on a plate-shaped base material, and includes the steps of acquiring three-dimensional shape data of the bent portion and manufacturing the bent portion by controlling a welding apparatus that forms weld beads based on the shape data. The step of manufacturing the bent portion includes manufacturing the bent portion by stacking weld beads in the circumferential direction of the bent portion, the height of which increases the further away from the center of curvature of the bent portion.

[0060] The additive manufacturing method described in Section 5 can achieve the same effects and advantages as the additive manufacturing system described in Section 1.

[0061] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The technical scope provided herein is defined by the claims rather than by the description of the embodiments above, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0062] 1 Additive manufacturing system, 10 Welding power supply unit, 20 Welding torch, 21 Nozzle, 22 Arc, 23 Melting section, 30 Control device, 31 Shape data acquisition unit, 32 Path generation unit, 33 Positioner rotation angle setting unit, 34 Database, 35 Welding condition setting unit, 36 Additive command unit, 40 Robot arm, 50 Wire feeding device, 51 Wire, 60 Positioner, 70 Weld bead, 71-75 Bead layer, 71a-75a Top surface, 80 Base material, 100 Object, 100a Bent section.

Claims

1. An additive manufacturing system that creates a molded object having a bent portion by stacking welding beads on a plate-shaped base material, A welding apparatus that melts a wire to form the weld bead, The welding apparatus is equipped with a control device that controls the welding apparatus to form the bent portion by stacking the welding beads, The control device is an additive manufacturing system that forms the bent portion by stacking weld beads in the circumferential direction of the bent portion, with the height increasing the further away from the center of curvature of the bent portion.

2. The system further includes a positioner for adjusting the inclination angle of the base material, The additive manufacturing system according to claim 1, wherein the control device controls the rotation angle of the positioner each time a layer of the weld bead of the bent portion is formed, thereby adjusting the inclination angle of the base material so that the upper surface, lower surface, or intermediate surface of each layer becomes horizontal.

3. The control device is The three-dimensional shape data of the bent portion is acquired, Based on the acquired shape data, a first height, which is the height of the inner end of the bend of each layer, and a second height, which is the height of the outer end of the bend, are set. The rotation angle of the positioner when forming each of the aforementioned layers is set, The additive manufacturing system according to claim 2, wherein welding conditions for forming each layer are set based on the first height, the second height, and the rotation angle of the positioner of each of the set layers.

4. The control device pre-stores data for the welding conditions using the first height, second height, and rotation angle of the positioner of each layer as parameters. The additive manufacturing system according to claim 3, wherein the control device refers to pre-stored welding condition data and sets welding conditions corresponding to the set first height, second height, and rotation angle of the positioner for each layer.

5. A layered fabrication method for creating a molded object having a bent portion by stacking welding beads on a plate-shaped base material, The steps include: acquiring three-dimensional shape data of the bent portion; The step includes shaping the bent portion by controlling a welding apparatus that forms the weld bead based on the shape data, A layered fabrication method comprising the step of forming the bent portion, which includes the step of forming the bent portion by stacking weld beads in the circumferential direction of the bent portion, the height of which increases as it moves further away from the center of curvature of the bent portion.

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