Control method and control device for stack molding device, and program

Abstract

A stacking condition of a deposited bead and a design value of a bead shape are obtained. The shape of an opening part and the shape of the periphery of the opening part are measured, and the shape contour including the opening part is obtained, wherein the opening part and the shape of the periphery of the opening part are defined between the welding beads formed based on the lamination condition or between the welding bead and the surrounding member. A space amount of the opening and a representative position of the opening are determined from the shape profile. And determining whether or not the opening is successfully closed on the basis of at least one of a comparison between the space amount and the design value of the bead shape, a comparison between the information representing the position and the target position of the deposited bead included in the lamination condition, and a formation of the root bead for the closing pass in which the opening is closed. When it is determined that the opening cannot be closed, the stacking condition of the closed pass is corrected.

Description

Technical Field

[0001] The present invention relates to a control method, a control device and a program for a stacking molding device. Background Art

[0002] In recent years, the demand for component manufacturing based on stacked modeling using 3D printing has increased, and research and development has been conducted toward the practical application of modeling using metal materials. For example, Patent Document 1 discloses a stacked modeling device that models a three-dimensional structure by stacking weld beads formed by melting metal welding wires. In the stacked modeling device of Patent Document 1, illumination light is irradiated from a measuring illumination unit, and the cross-sectional height distribution of the modeled object is calculated based on the detection result of the reflected light, and the width of the modeled object is calculated based on the cross-sectional height distribution. The processing conditions are controlled in accordance with the width of the modeled object.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent No. 6896193 Summary of the invention

[0006] Problems to be solved by the invention

[0007] In addition, in the modeling based on the stacking of weld beads, sometimes it is necessary to stack the weld beads horizontally or to form a cantilevered shape according to the modeling shape. In such a modeling, the size of the weld beads may differ between the stacking plan and the actual due to the melting of the weld beads. In this case, when the weld beads are joined to each other or to other components after the horizontal stacking or cantilevering modeling, the width of the weld bead required for the closing pass to close the joint (the amount of space when closing) changes along the length direction of the weld bead. When the closure is constructed in such a state, the quality of each location will be different due to the difference in the amount of space, which becomes a problem in terms of strength and quality management.

[0008] Therefore, an object of the present invention is to provide a control method, a control device, and a program for a stacking molding device that manage the amount of space required in a closed pass and can automatically set appropriate welding conditions for the amount of space.

[0009] Means for solving problems

[0010] The present invention is constituted by the following structure.

[0011] (1) A control method for a stacking molding device, the stacking molding device comprising a robot for moving a welding torch and stacking weld beads formed by a tip of the welding torch to mold a molded object,

[0012] in,

[0013] The control method of the stacking molding device comprises the following steps:

[0014] acquiring design values ​​of lamination conditions and weld bead shape of the weld bead formed by movement of the welding torch;

[0015] measuring the shapes of an opening defined between the weld beads formed based on the lamination conditions or between the weld beads and a surrounding member and the surroundings of the opening, and obtaining a shape contour including the opening;

[0016] determining a spatial amount representing a size of a space of the opening and a representative position of the opening according to the shape contour;

[0017] Regarding a closing pass in which the opening is closed by a deposited weld bead formed based on the stacking condition, whether the closing of the opening is successful or not is determined based on at least any one of a comparison between the space amount and a design value of the weld bead shape, a comparison between the information of the representative position and a target position of the deposited weld bead included in the stacking condition, and whether a root weld bead can be formed; and

[0018] When it is determined that the opening cannot be closed by the closing pass, the stacking condition of the closing pass is corrected.

[0019] (2) A control device for a stacking molding device, the stacking molding device comprising a robot for moving a welding torch and stacking weld beads formed by the tip of the welding torch to mold a molded object,

[0020] in,

[0021] The control device of the stacking molding device comprises:

[0022] a condition acquisition unit that acquires a stacking condition and a design value of a weld bead shape of the weld bead formed by movement of the welding torch;

[0023] a contour measuring unit that measures the shape of an opening defined between the weld beads formed based on the lamination conditions or between the weld beads and a surrounding member and the shape of the opening periphery, and obtains a shape contour including the opening;

[0024] a determining unit that determines a space amount representing a size of a space of the opening and a representative position of the opening based on the shape contour;

[0025] a determination unit that determines, with respect to a closing pass in which the opening is closed by a deposited weld bead formed based on the stacking condition, whether the closing of the opening is successful or not based on at least any one of a comparison between the space amount and a design value of the weld bead shape, a comparison between the information of the representative position and a target position of the deposited weld bead included in the stacking condition, and whether a root weld bead can be formed; and

[0026] A correction unit corrects the lamination condition of the closing pass when it is determined that the opening cannot be closed by the closing pass.

[0027] (3) A program for executing a control step of a stacking molding device having a robot for moving a welding torch and stacking weld beads formed by the tip of the welding torch to mold a molded object,

[0028] in,

[0029] The program is used to make the computer execute the following steps:

[0030] acquiring design values ​​of lamination conditions and weld bead shape of the weld bead formed by movement of the welding torch;

[0031] measuring the shapes of an opening defined between the weld beads formed based on the lamination conditions or between the weld beads and a surrounding member and the surroundings of the opening, and obtaining a shape contour including the opening;

[0032] determining a spatial amount representing a size of a space of the opening and a representative position of the opening according to the shape contour;

[0033] Regarding a closing pass in which the opening is closed by a deposited weld bead formed based on the stacking condition, whether the closing of the opening is successful or not is determined based on at least any one of a comparison between the space amount and a design value of the weld bead shape, a comparison between the information of the representative position and a target position of the deposited weld bead included in the stacking condition, and whether a root weld bead can be formed; and

[0034] When it is determined that the opening cannot be closed by the closing pass, the stacking condition of the closing pass is corrected.

[0035] Effects of the Invention

[0036] According to the present invention, the amount of space required in a closed pass is managed and appropriate welding conditions for the amount of space can be automatically set. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic diagram showing the overall structure of the stacking molding device.

[0038] Figure 2 It is a functional block diagram of the control device.

[0039] Figure 3A This is a schematic diagram showing an opening portion when deposited weld beads are stacked to form a partition wall having an internal space.

[0040] Figure 3B This is a schematic diagram showing an opening portion when deposited weld beads are stacked to form a partition wall having an internal space.

[0041] Figure 4 yes Figure 3A A top view of the opening shown.

[0042] Figure 5 The present invention is a flowchart showing the steps of closing the weld bead of the pass by sealing the opening formed by laminating the weld bead.

[0043] Figure 6 It is an explanatory diagram schematically showing the state of measurement of shape contour.

[0044] Figure 7 It is an explanatory diagram showing the detection profile of the detected reflected light.

[0045] Figure 8 This is a graph showing the shape contour measured by the contour measuring unit using the shape detecting unit.

[0046] Fig. 9 It is an explanatory diagram showing an opening and a closing pass for closing the opening.

[0047] Fig. 10A It is an explanatory diagram of a root pass and is a schematic cross-sectional view when a root pass is not formed at the position of a closed pass.

[0048] Fig. 10B It is an explanatory diagram of a root pass and is a schematic cross-sectional view when the root pass is formed at the position of a closed pass.

[0049] Fig.11 This is a photograph of a cross section of a weld portion when a notch-shaped defect in welding occurs in the closing pass. DETAILED DESCRIPTION

[0050] The stacking molding device shown here is an example, and other structures may be used as long as it is a device that has a robot arm that holds a welding torch and stacks weld beads formed by the tip of the welding torch based on set stacking conditions to mold a molded object.

[0051] <Structure of stacking molding device>

[0052] Figure 1 It is a schematic diagram showing the overall structure of the stacking molding device.

[0053] The stacking molding apparatus 100 includes a control device 11 and a molding unit 13. The molding unit 13 includes a robot 15, a filling material supply unit 17, a robot controller 19, a heat source controller 21, and a shape detector 23.

[0054] The robot control unit 19 controls the robot 15 and the heat source control unit 21. A controller (not shown) is connected to the robot control unit 19, and an operator can instruct any operation of the robot control unit 19 via the controller.

[0055] The manipulator 15 is, for example, a multi-joint robot, and is supported so as to be able to continuously supply the filler material M to the welding torch 25 provided on the front end axis. The welding torch 25 is maintained in a state where the filler material M protrudes from the front end. The position and posture of the welding torch 25 can be arbitrarily set three-dimensionally within the range of the degrees of freedom of the robot arm constituting the manipulator 15. The manipulator 15 preferably has more than six degrees of freedom, and preferably allows the axial direction of the heat source at the front end to be arbitrarily changed. In addition to Figure 1 In addition to the multi-joint robot with four or more axes shown above, various forms such as a robot having angle adjustment mechanisms on two or more orthogonal axes may be used.

[0056] The welding torch 25 has a shielding nozzle not shown in the figure, and a shielding gas is supplied from the shielding nozzle. The shielding gas blocks the atmosphere, prevents oxidation and nitridation of the molten metal during welding, and suppresses poor welding. The arc welding method used in this structure can be any of a consumable electrode type such as covered arc welding or carbon dioxide gas arc welding, a non-consumable electrode type such as TIG (Tungsten InertGas) welding or plasma arc welding, and is appropriately selected according to the modeling object. Gas shielded arc welding is taken as an example for explanation. In the case of the consumable electrode type, a conductive nozzle is arranged inside the shielding nozzle, and the filler material M supplied with current is held in the conductive nozzle. While holding the filler material M, the welding torch 25 generates an arc from the front end of the filler material M in a shielding gas atmosphere.

[0057] The filler material supply unit 17 supplies the filler material M toward the welding torch 25. The filler material supply unit 17 includes a reel 17a on which the filler material M is wound, and a delivery mechanism 17b that delivers the filler material M from the reel 17a. The filler material M is delivered to the welding torch 25 while being transported in the forward direction or the reverse direction as required by the delivery mechanism 17b. The delivery mechanism 17b is not limited to a push type that is arranged on the side of the filler material supply unit 17 and pushes out the filler material M, but may also be a pull type or a push-pull type that is arranged on a robot arm or the like.

[0058] The heat source control unit 21 is a welding power source that supplies power required for welding performed by the robot 15. The heat source control unit 21 adjusts the welding current and welding voltage supplied when forming a weld bead that melts and solidifies the filler material M. In addition, the filler material supply speed of the filler material supply unit 17 is adjusted in conjunction with the welding conditions such as the welding current and welding voltage set by the heat source control unit 21.

[0059] The heat source for melting the filler material M is not limited to the above-mentioned arc. For example, a heat source based on a heating method based on a combination of arc and laser, a heating method using plasma, a heating method using electron beam or laser, etc. can also be used. In the case of heating using an electron beam or laser, the amount of heat can be controlled more finely, and the state of the formed weld can be maintained more appropriately, which helps to further improve the quality of the stacked structure. In addition, there is no particular limitation on the material of the filler material M. For example, the type of filler material M used can be different depending on the characteristics of the molded object Wk such as mild steel, high-tensile steel, aluminum, aluminum alloy, nickel, and nickel-based alloy.

[0060] The shape detector 23 is provided at or near the front end axis of the robot 15, and the front end vicinity of the welding torch 25 is set as a measurement area. The shape detector 23 may be another detection mechanism provided at a position different from the welding torch 25.

[0061] The shape detection unit 23 of this structure moves together with the welding torch 25 by the driving of the robot 15, and measures the shape of the weld bead B and the part that becomes the base when the weld bead B is formed. As the shape detection unit 23, for example, a laser displacement sensor that obtains the reflected light of the irradiated laser as height information can be used. In addition, as the shape detection unit 23, other detection mechanisms such as a camera for three-dimensional shape measurement can also be used.

[0062] The control device 11 controls the above-mentioned parts in a unified manner. The control device 11 is composed of hardware using an information processing device such as a PC (Personal Computer). The functions of the control device 11 are realized by a control device such as a CPU (Central Processing Unit), an MPU (Micro Processor Unit) or a dedicated circuit, etc., which reads out a program with a specific function stored in a storage device not shown in the figure and executes the program. As a storage device, a RAM (Random Access Memory) as a volatile storage area, a ROM (Read Only Memory) as a non-volatile storage area, a storage device such as an HDD (Hard Disk Drive), and an SSD (Solid State Drive) can be exemplified. In addition to the above-mentioned form, the control device 11 can also be another computer remotely connected from the stacking molding device 100 via a network or the like.

[0063] The stacking molding device 100 of the above-mentioned structure operates according to the molding program created based on the molding plan of the molded object Wk. The molding program is composed of a plurality of command codes and is created based on an appropriate algorithm according to various conditions such as the shape, material, and heat input of the molded object Wk. If the supplied filler material M is melted and solidified while the welding torch 25 is moved according to the molding program, a linear weld bead B as a molten solidified body of the filler material M is formed on the base 27. That is, the robot control unit 19 drives the robot 15 and the heat source control unit 21 based on the prescribed molding program provided from the control device 11. The robot 15 melts the filler material M by an arc and moves the welding torch 25 according to the command from the robot control unit 19 to form the weld bead B. By sequentially forming and stacking the weld bead B in this way, the molded object Wk of the intended shape is obtained.

[0064] The control device 11 may also have a function of outputting a drive signal to a machining device 33 having a cutting or grinding tool 31 such as an end mill or a drill on the distal end shaft 29 so as to perform cutting or grinding of the weld bead B at a predetermined timing.

[0065] Figure 2 1 is a functional block diagram of the control device 11. The control device 11 includes a condition acquisition unit 35, a contour measurement unit 37, a calculation unit 39, a determination unit 41, and a correction unit 43. The functions of the above-mentioned units will be described in detail later.

[0066] Figure 3A , Figure 3B This is a schematic diagram showing an opening portion when deposited weld beads are stacked to form a partition wall having an internal space.

[0067] like Figure 3A As shown in the figure, a pair of weld beads B are formed at positions separated from each other on the base 27, and a new weld bead B is stacked on each weld bead B. A pair of stacked bodies 45 composed of multiple layers of weld beads B are cantilevered and formed in a manner close to each other, and the weld bead Bc formed by the last pass (closing pass) of the weld bead formation closes the opening 47 generated between the weld beads Bt of the uppermost layer of each stacked body 45. In this way, an internal space 49 is formed inside the pair of stacked bodies 45. In this specification, the shape in which the weld bead Bc and the weld bead Bt are fused is referred to as a "closed portion".

[0068] The above-mentioned opening 47 is formed between a pair of stacked bodies 45, but it may also be formed between a pair of stacked bodies 45. Figure 3B As shown, the weld bead Bt is formed between the uppermost layer of the stacked body 45 and the surrounding member 51 such as the existing side wall or other member.

[0069] Figure 4 yes Figure 3A 4 is a top view of the opening 47 shown in FIG. As for the actual opening 47, the shape of the deposited weld bead B of the uppermost layer of the stack 45 is not constant along the welding direction WD, and is formed with different widths W. Therefore, when the control device 11 of this structure stacks the deposited weld bead B to form a stack having an internal space, the control device 11 closes the openings 47 formed on the upper parts of a pair of stacks stacked from the lower side by using the deposited weld bead of the closing pass. At this time, the control device 11 measures the shape of the opening 47 before the weld bead is formed, and corrects the formation conditions of the deposited weld bead that closes the opening 47 according to the shape of the opening 47. The stacking conditions of the deposited weld bead Bc formed by the closing pass can be set in real time during the molding process so that the opening 47 can be reliably closed according to the shape of the opening 47.

[0070] <Steps from stacking weld beads to closing the opening>

[0071] Figure 5 The flowchart shows the steps of closing the opening formed by the stacking of weld beads by using the weld beads of the closing pass. Figure 2 The components of the control device 11 are implemented as shown.

[0072] First, the condition acquisition unit 35 acquires Figure 1 The stacking conditions of the deposited weld bead B and the design value of the weld bead shape (S1) are shown in FIG. The stacking conditions include information such as the formation trajectory (passes) of the deposited weld bead B when the molded object Wk is molded using the deposited weld bead B and the welding conditions of the deposited weld bead B. In addition, the information of the stacking conditions can also be extracted from the aforementioned molding program.

[0073] The control device 11 drives the shaping unit 13 at a predetermined timing based on the acquired lamination conditions to form the weld bead B and start shaping ( S2 ).

[0074] Next, the contour measuring unit 37 measures the shape of the opening 47 defined between the weld beads B formed based on the lamination conditions or between the weld beads B and other members to obtain a shape contour ( S3 ).

[0075] Figure 6 This is an explanatory diagram schematically showing the measurement of the shape profile. The shape detection unit 23 is arranged, for example, at the rear of the moving direction (welding direction WD) of the welding torch 25, and moves together with the movement of the welding torch 25. The shape detection unit 23 performs measurement based on the light section method of irradiating slit light from an oblique direction toward the formed weld bead B and detecting the reflected light of the irradiated slit light. The method of shape detection is not limited to this, and other methods may be used.

[0076] Figure 7 : is an explanatory diagram showing the detected reflected light detection profile Prf. The upwardly protruding area of ​​the reflected light detection profile Prf indicates the position of the weld bead B. That is, the reflected light detection profile Prf is a shape profile indicating the height information of the measurement object.

[0077] Figure 8 : is a graph showing the shape contour measured by the contour measuring unit 37 using the shape detecting unit 23 .

[0078] The shape profile includes a pair of convex portions corresponding to a pair of weld beads B (laminated body 45) arranged opposite to each other, and a region corresponding to the opening 47 between the pair of convex portions. Figure 3A As shown, the shape of the uppermost portion (the uppermost weld bead Bt) of each of the pair of stacked bodies 45 that are cantilevered is measured.

[0079] Here, the vertex of one of the pair of convex portions (the convex portion on the left) is set as the first maximum height point P1, and the vertex of the other convex portion (the convex portion on the right) is set as the second maximum height point P2. In addition, the point of the front end protruding downward from the first maximum height point P1 along the opening is set as the first protrusion front end point P3, and the point of the front end protruding downward from the second maximum height point P2 along the opening is set as the second protrusion front end point P4.

[0080] The calculation unit 39 determines a space amount representing the size of the space of the opening or a representative position of the opening based on the obtained shape contour (S4). Examples of the space amount include the width, depth, and cross-sectional area of ​​the opening in a cross section of the weld bead perpendicular to the weld bead forming direction (welding direction WD), but are not limited thereto.

[0081] For example, the width of the opening can include the width W1 between the first maximum height point P1 and the second maximum height point P2 (the width between the two points of the maximum height), and the width W2 between the first protrusion front end point P3 and the second protrusion front end point P4 (the width between the two points of the extension extending downward). In addition, the depth of the opening can also be the height difference between the higher side of the first maximum height point P1 and the second maximum height point P2 (here P1) and the lower side of the first protrusion front end point P3 and the second protrusion front end point P4 (here P4) as the depth D. The depth D represents the maximum depth in the opening of the measured shape contour. In addition, the difference between the average height of the first maximum height point P1 and the second maximum height point P2 and the average height of the first protrusion front end point P3 and the second protrusion front end point P4 can also be set as the depth D. The cross-sectional area A may be the area of ​​a quadrilateral with the above-mentioned points P1, P2, P3, P4 as vertices, or the area of ​​the smallest circle enclosed by the points P1, P2, P3, P4, or the area of ​​any geometric figure with the above-mentioned points as vertices.

[0082] The representative position is any position (coordinate) inside a geometric figure with the above-mentioned points P1, P2, P3, and P4 as vertices, and may also be set to the position (coordinate) of the center point or centroid of the above-mentioned geometric figure.

[0083] Next, the determination unit 41 determines whether the closure of the opening 47 is successful or not based on at least any one of a comparison between the space amount and the design value of the weld bead shape, a comparison between the information of the representative position and the target position of the weld bead included in the stacking conditions, and whether a root weld bead (details will be described later) can be formed (S5).

[0084] Specifically, the obtained spatial quantities such as the width W1, W2, depth D, and cross-sectional area A of the area corresponding to the opening are compared with the design value of the size of the weld bead or the weld bead shape determined based on the stacking conditions. When the difference between the obtained spatial quantity and the design value is greater than a specified threshold, it is determined that the stacking conditions of the closed pass need to be corrected. In addition, relative to the above-mentioned points P1, P2, P3, P4, the coordinates of the inner side of the geometric figure, the coordinates of the center point or the center of gravity, and other representative positions, when compared with the torch target position (weld bead forming track) included in the stacking conditions, when the offset (difference) between the obtained representative position and the torch target position is greater than a specified threshold, it is determined that the stacking conditions of the closed pass need to be corrected. These judgments can be implemented on one side only, or both can be combined. In particular, when the two are combined, the stacking conditions of the weld bead of the closed pass can be precisely adjusted. In addition, the success or failure of the closure can be replaced by whether the root weld can be formed for judgment. In this case, the shape contour ( Figure 7 The slope of the shape profile Prf shown in the figure, the distance between the closest points of a pair of convex portions (described later) Fig. 10A , Fig. 10B Wa shown) or the thickness of the convex portion (e.g. Figure 8 The depth D) of the opening 47 is compared with the design value, and when the deviation of both exceeds the predetermined value, it is determined that the root bead cannot be formed. In this way, the success of the closure can be determined more accurately by replacing the determination with whether the root bead can be formed. In addition, the determination of the success of the closure of the opening 47 can also be implemented by appropriately combining the above-mentioned comparisons and whether the root bead can be formed.

[0085] It should be noted that, when the shape of the opening portion deviates greatly from the design shape and the lamination of the closing pass is difficult, it can also be determined whether to continue the lamination molding as it is or to interrupt it. For example, when local concavities and convexities are generated in the opening portion to form a narrow portion, if the weld bead is formed as it is, there is a possibility that pores will be generated in the narrow portion. In this case, the control device 11 can also control the lamination molding at an appropriate time. Figure 1 The machining device 33 shown in the figure can be used to perform repairs such as cutting and grinding of the narrow part. According to this, the processable range of the shape of the opening can be expanded.

[0086] When the determination unit 41 determines that the opening cannot be closed or that the state is not good even if it can be closed, the correction unit 43 corrects the lamination conditions of the closing pass (S6). Thus, the lamination conditions corresponding to the actual shape of the opening are set for the closing pass. Then, the weld bead of the closing pass is formed based on the newly set lamination conditions (S7).

[0087] When the determination unit 41 determines that the opening can be closed, a closed pass weld bead is formed as is in accordance with the set lamination conditions ( S7 ).

[0088] In the closing pass for closing the opening 47, the accumulation of droop and deformation of the deposited weld beads stacked in the passes below it may not be fully closed under the original plan, in other words, the designed stacking conditions. Therefore, in order to perform the shaping as planned, the stacking conditions of the closing pass are corrected to match the shape of the opening. The specific content of correcting the stacking conditions of the closing pass is described below.

[0089] Fig. 9 It is an explanatory diagram showing an opening and a closing pass for closing the opening.

[0090] Consider Fig. 9 As shown in FIG. 4 , the width of the opening 47 is not constant but varies along the welding direction WD. In this case, for example, Fig. 9 In the section where the width of the opening 47 is extremely narrow, such as the area K1 of the welding arc, the wire feed speed is reduced or the welding speed is increased compared with other sections in order to suppress the amount of weld deposition. On the contrary, in the section where the width is widened, the wire feed speed is increased or the welding speed is reduced in order to increase the amount of weld deposition. It should be noted that the mixing ratio of the shielding gas can also be adjusted in the case where the back side of the portion where the opening is closed due to the change in the amount of weld deposition may not form a root weld bead. For example, in the case of Ar and CO 2 In the mixed protective gas, by making CO 2 The ratio of Ar-CO increases, thereby increasing the penetration of the molten metal. Therefore, in the closed pass lamination, the Ar-CO 2 The mixing ratio of the shielding gas is adjusted so that the root pass can be formed at all times. It is further preferred that the Ar—CO mixture is adjusted in conjunction with any of the changes in the amount of deposit, the amount of heat input, and the target position. 2 The mixing ratio of the shielding gas can suppress the occurrence of shape defects and defects caused by closed weld beads.

[0091] It should be noted that the root pass mentioned here has substantially the same meaning as the term defined in JIS Z 3001. Fig. 10A , Fig. 10B The figure below shows the root weld bead. Fig. 10A is a schematic cross-sectional view in which no root weld bead is formed at the position of the closed pass. Fig. 10B1 is a schematic cross-sectional view of a case where a root weld bead Bb is formed at the position of a closed pass. A closed pass is a pass that fills a gap Wa between the tops of a pair of weld beads B that are stacked closely together, and a deposited weld bead Bc formed by the closed pass is shown as a hatched area. Fig. 10A , Fig. 10B Point P represents the target position for weld bead formation. Fig. 10B The root bead Bb shown means a smooth-surfaced weld bead formed on the opposite side (back side) of the torch side in one-side welding in which welding is performed only from one side, and refers to weld metal formed by one pass. Fig. 10A In the absence of a root bead, the gap portion may be thinned to reduce strength, or a notch C may be formed between the closed portion and the bead adjacent to the closed portion, which may become a starting point for cracking. Fig.11 This is a photograph of a cross section of a welded portion when a notch-shaped poor welding occurs in a closing pass. If a root bead is not formed in a closing pass, welding quality may be reduced, so it is preferable to form a root bead in a closing pass.

[0092] In the case where the oscillation is a prerequisite in the closed pass, the oscillation width may be smaller in the region K1 than in other regions. Furthermore, in order to prevent the weld bead of the closed pass from melting after lamination, the heat input of the weld bead may be adjusted according to the aforementioned space amount. For example, when the width of the opening 47 is too narrow relative to the assumed space amount, the welding current or welding voltage may be reduced to reduce the heat input. On the contrary, when the width of the opening 47 is too wide relative to the assumed space amount, the welding current or welding voltage may be increased.

[0093] In addition, the target position of the welding torch 25 in the closing pass for closing the opening 47 may be corrected to the above-mentioned representative position. For example, the target position may be corrected to be the center position or the center of gravity position of the opening 47. In this way, the position of the welding torch 25 is kept appropriate, and the idle swing of the welding torch and the interference with other components due to the deviation between the target position of the welding torch and the position of the weld bead surface and the failure to form the weld bead as expected can be suppressed. In addition, the opening 47 can be closed more reliably by using the weld bead of the closing pass.

[0094] Fig. 9 The target position 53 of the welding torch 25 shown in FIG. 4 is preferably set on a line where the distances Wa and Wb from the weld beads B on both sides of the opening 47 are equal. Fig. 9There may be an asymmetric section in the width direction orthogonal to the welding direction WD, such as the region K2 of the welding torch 25. In this case, the target position 53a may be added at a position offset from the center in the width direction so that the welding torch 25 is displaced in the width direction in the region K2. That is, the added target position 53a is set on either side (ie, the side) of the pair of opposing weld beads B forming the opening 47 that widens the opening 47. Fig. 9 By adding the target position 53a, the closing pass is set to bend toward the side of widening the width of the opening 47, and the weld bead is placed at the widened portion. Therefore, the opening 47 can be closed while suppressing the generation of strain, defect, and unwelded portion.

[0095] As described above, according to the control method of the stacking molding device, after horizontal stacking or overhanging molding, when the weld beads are joined to each other or to other components, a weld bead of a closed pass that closes the joint portion can be formed under appropriate stacking conditions that meet the amount of space filled by the weld bead of necessary width, necessary thickness, etc. Thus, even if the size of the weld bead is different between the stacking plan and the actual weld bead and the shape of the joint portion (opening 47) changes, the stacking conditions corresponding to the shape change are automatically set, so that the joint quality of the opening can be improved. Therefore, there is no difference in quality at each location, and a molded object with good strength and quality control can be obtained.

[0096] In addition, since the spatial amount or representative position of the opening between the weld beads is processed as a characteristic quantity for control, information such as the required weld amount becomes more accurate compared to the case where the shape of the weld bead to be formed itself is processed as a characteristic quantity, and the opening can be closed more reliably.

[0097] The present invention is not limited to the above-mentioned embodiments, and combinations of the structures of the embodiments, changes and applications by those skilled in the art based on the description in the specification and known techniques are also contemplated by the present invention and are included in the scope of protection requested.

[0098] As described above, the present specification discloses the following matters.

[0099] (1) A control method for a stacking molding device, the stacking molding device comprising a robot for moving a welding torch and stacking weld beads formed by a tip of the welding torch to mold a molded object,

[0100] in,

[0101] The control method of the stacking molding device comprises the following steps:

[0102] acquiring design values ​​of lamination conditions and weld bead shape of the weld bead formed by movement of the welding torch;

[0103] measuring the shapes of an opening defined between the weld beads formed based on the lamination conditions or between the weld beads and a surrounding member and the surroundings of the opening, and obtaining a shape contour including the opening;

[0104] determining a spatial amount representing a size of a space of the opening and a representative position of the opening according to the shape contour;

[0105] Regarding a closing pass in which the opening is closed by a deposited weld bead formed based on the stacking condition, whether the closing of the opening is successful or not is determined based on at least any one of a comparison between the space amount and a design value of the weld bead shape, a comparison between the information of the representative position and a target position of the deposited weld bead included in the stacking condition, and whether a root weld bead can be formed; and

[0106] When it is determined that the opening cannot be closed by the closing pass, the stacking condition of the closing pass is corrected.

[0107] According to the control method of the stacking molding device, the shape of the opening formed by molding is measured to obtain the shape profile, and the success or failure of the closure formed by the closing pass of the opening can be determined based on the shape profile. Therefore, by correcting the stacking conditions of the closing pass when it is predicted that the opening cannot be closed, the opening can be reliably closed.

[0108] (2) The control method of the stacking molding device according to (1), wherein:

[0109] The space amount includes any one of a width, a depth, and a cross-sectional area of ​​a region corresponding to the opening in the shape outline.

[0110] According to the control method of the stacking molding device, any one of the width, depth and cross-sectional area of ​​the area corresponding to the opening can be simply calculated using the shape profile, so that the stacking condition can be corrected earlier. In other words, feedback control corresponding to the spatial amount can be quickly performed, thereby shortening the processing time.

[0111] (3) The control method of the stacking molding device according to (1) or (2), wherein:

[0112] The representative position is any one of the points on the inside of a geometric figure having as vertices the first maximum height point of a convex portion of one of a pair of convex portions sandwiching the opening portion in the shape contour, a first protrusion front end point protruding from the first maximum height point toward the bottom of the opening portion, and the second maximum height point of the convex portion of the other side, and a second protrusion front end point protruding from the second maximum height point toward the bottom of the opening portion.

[0113] According to the control method of the stacking molding device, each representative position can be easily calculated using the shape profile, so the stacking condition can be corrected earlier. In other words, feedback control corresponding to the space amount can be quickly performed, and the processing time can be shortened.

[0114] (4) The control method of a stacking molding device according to any one of (1) to (3), wherein:

[0115] Correction of the lamination condition of the closing pass includes adjusting a welding amount or a heat input amount of the welding bead for closing the opening according to a width of the opening obtained from the shape profile.

[0116] According to the control method of the stacking molding device, when the width of the opening portion is different from the assumed width, the amount of deposited weld can be adjusted by increasing or decreasing the wire feed speed and the welding speed or by increasing or decreasing the welding current and the welding voltage to adjust the amount of heat input, so that a closed pass deposited weld can be formed under appropriate conditions. Thus, excessive or insufficient depositing of the weld and melting of the weld can be prevented.

[0117] (5) The control method of a stacking molding device according to any one of (1) to (4), wherein:

[0118] The correction of the lamination condition of the closing pass includes correcting a target position of the weld bead that closes the opening to the representative position.

[0119] According to the control method of the stacking molding device, the target position of the closed-pass weld bead is corrected to the representative position, thereby maintaining the appropriate position of the welding torch, thereby suppressing idle swing of the welding torch and interference with other components.

[0120] (6) The control method of a stacking molding device according to any one of (1) to (5), wherein:

[0121] The correction of the stacking condition of the closing pass includes adding a target position of the closing pass.

[0122] The additional target position is provided so as to be offset to one side of a pair of opposing weld beads forming the opening, which side widens the opening.

[0123] According to the control method of the stacking molding device, the closing pass is set to bend toward the side where the width of the opening is widened by adding the target position, and the weld bead is placed at the widened portion. Therefore, the opening can be closed while suppressing the generation of strain, defect, and unwelded portion.

[0124] (7) The control method of a stacking molding device according to any one of (1) to (6), wherein:

[0125] Correction of the lamination condition of the closed pass includes adjusting a mixing ratio of a mixed shielding gas used in lamination of the weld deposit.

[0126] According to the control method of the stacking molding device, the mixing ratio of the mixed shielding gas is adjusted in the stacking of closed passes so that the root weld can always be formed, which can suppress the reduction in strength caused by the thin wall of the closed part, the closed part becoming the starting point of cracks, and other shape defects and defects.

[0127] (8) A control device for a stacking molding device, the stacking molding device comprising a robot for moving a welding torch and stacking weld beads formed by the tip of the welding torch to mold a molded object,

[0128] in,

[0129] The control device of the stacking molding device comprises:

[0130] a condition acquisition unit that acquires a stacking condition and a design value of a weld bead shape of the weld bead formed by movement of the welding torch;

[0131] a contour measuring unit that measures the shape of an opening defined between the weld beads formed based on the lamination conditions or between the weld beads and a surrounding member and the shape of the opening periphery, and obtains a shape contour including the opening;

[0132] a determining unit that determines a space amount representing a size of a space of the opening and a representative position of the opening based on the shape contour;

[0133] a determination unit that determines, with respect to a closing pass in which the opening is closed by a deposited weld bead formed based on the stacking condition, whether the closing of the opening is successful or not based on at least any one of a comparison between the space amount and a design value of the weld bead shape, a comparison between the information of the representative position and a target position of the deposited weld bead included in the stacking condition, and whether a root weld bead can be formed; and

[0134] A correction unit corrects the lamination condition of the closing pass when it is determined that the opening cannot be closed by the closing pass.

[0135] According to the control device of the stacking molding device, the shape of the opening formed by molding is measured to obtain the shape profile, and the success or failure of the closure formed by the closing pass of the opening can be determined based on the shape profile. Therefore, by correcting the stacking conditions of the closing pass when it is predicted that the opening cannot be closed, the opening can be reliably closed.

[0136] (9) A program for executing a control step of a stacking molding device having a robot for moving a welding torch and stacking weld beads formed by the tip of the welding torch to mold a molded object,

[0137] in,

[0138] The program is used to make the computer execute the following steps:

[0139] acquiring design values ​​of lamination conditions and weld bead shape of the weld bead formed by movement of the welding torch;

[0140] measuring the shapes of an opening defined between the weld beads formed based on the lamination conditions or between the weld beads and a surrounding member and the surroundings of the opening, and obtaining a shape contour including the opening;

[0141] determining a spatial amount representing a size of a space of the opening and a representative position of the opening according to the shape contour;

[0142] Regarding a closing pass in which the opening is closed by a deposited weld bead formed based on the stacking condition, whether the closing of the opening is successful or not is determined based on at least any one of a comparison between the space amount and a design value of the weld bead shape, a comparison between the information of the representative position and a target position of the deposited weld bead included in the stacking condition, and whether a root weld bead can be formed; and

[0143] When it is determined that the opening cannot be closed by the closing pass, the stacking condition of the closing pass is corrected.

[0144] According to the program, the shape of the opening formed by molding is measured to obtain the shape profile, and the success or failure of the closure formed by the closing pass of the opening can be determined based on the shape profile. Therefore, by correcting the stacking conditions of the closing pass when it is predicted that the opening cannot be closed, the closure of the opening can be reliably performed.

[0145] It should be noted that the present application is based on Japanese patent application (Japanese Patent Application No. 2022-106144) filed on June 30, 2022, the contents of which are incorporated herein by reference.

[0146] Description of reference numerals:

[0147] 11 Control Device

[0148] 13 Modeling Department

[0149] 15. Robot

[0150] 17 Filling material supply unit

[0151] 17a Reel

[0152] 17b Delivery mechanism

[0153] 19 Robot control unit

[0154] 21 Heat source control department

[0155] 23. Shape detection unit

[0156] 25 Welding torch

[0157] 27 Base

[0158] 29 Front shaft

[0159] 31 Tools

[0160] 33 Machining equipment

[0161] 35 Conditional Acquisition Department

[0162] 37 Contour measurement unit

[0163] 39 Operation unit

[0164] 41 Judgment Department

[0165] 43 Correction Department

[0166] 45 Laminated

[0167] 47 Opening

[0168] 49 Interior Space

[0169] 51 Surrounding components

[0170] 53, 53a Target location

[0171] 100 Layered Modeling Device

[0172] A Cross-sectional area

[0173] B, Bc, Bt deposited weld

[0174] D Depth

[0175] K1, K2 area

[0176] M Filling material

[0177] P1 First maximum height point

[0178] P2 Second maximum height point

[0179] P3 The first protruding front point

[0180] P4 Second protruding front point

[0181] Prf detection contour

[0182] W, W1, W2 Width

[0183] WD welding direction

[0184] Wk modeling object.

Claims

1. A control method for a stacking molding device, the stacking molding device comprising a robot for moving a welding torch and stacking weld beads formed by the front end of the welding torch to mold a molded object, in, The control method of the stacking molding device comprises the following steps: acquiring design values ​​of lamination conditions and weld bead shape of the weld bead formed by movement of the welding torch; measuring the shapes of an opening defined between the weld beads formed based on the lamination conditions or between the weld beads and a surrounding member and the surroundings of the opening, and obtaining a shape contour including the opening; determining a spatial amount representing a size of a space of the opening and a representative position of the opening according to the shape contour; Regarding a closing pass for closing the opening portion by a deposited weld bead formed based on the stacking condition, whether the closing of the opening portion is successful or not is determined based on at least one of a comparison between the space amount and a design value of the weld bead shape, a comparison between the information of the representative position and a target position of the deposited weld bead included in the stacking condition, and whether a root weld bead can be formed; as well as When it is determined that the opening cannot be closed by the closing pass, the stacking condition of the closing pass is corrected.

2. The control method of the stacking molding device according to claim 1, wherein: The space amount includes any one of a width, a depth, and a cross-sectional area of ​​a region corresponding to the opening in the shape outline.

3. The control method of the stacking molding device according to claim 1, wherein: The representative position is any one of the points on the inside of a geometric figure having as vertices the first maximum height point of a convex portion of one of a pair of convex portions sandwiching the opening portion in the shape contour, a first protrusion front end point protruding from the first maximum height point toward the bottom of the opening portion, and the second maximum height point of the convex portion of the other side, and a second protrusion front end point protruding from the second maximum height point toward the bottom of the opening portion.

4. The control method of the stacking molding device according to claim 1, wherein: Correction of the lamination condition of the closing pass includes adjusting a welding amount or a heat input amount of the welding bead for closing the opening according to a width of the opening obtained from the shape profile.

5. The control method of the stacking molding device according to claim 1, wherein: The correction of the lamination condition of the closing pass includes correcting a target position of the weld bead that closes the opening to the representative position.

6. The control method of the stacking molding device according to claim 1, wherein: The correction of the stacking condition of the closing pass includes adding a target position of the closing pass. The additional target position is provided so as to be offset to one side of a pair of opposing weld beads forming the opening, which side widens the opening.

7. The control method of the stacking molding device according to claim 1, wherein: Correction of the lamination condition of the closed pass includes adjusting a mixing ratio of a mixed shielding gas used in lamination of the weld deposit.

8. A control device for a stacking molding device, the stacking molding device comprising a robot for moving a welding torch and stacking weld beads formed by the front end of the welding torch to mold a molded object, in, The control device of the stacking molding device comprises: a condition acquisition unit that acquires a stacking condition and a design value of a weld bead shape of the weld bead formed by movement of the welding torch; a contour measuring unit that measures the shape of an opening defined between the weld beads formed based on the lamination conditions or between the weld beads and a surrounding member and the shape of the opening periphery, and obtains a shape contour including the opening; a determination unit that determines a space amount representing a size of a space of the opening and a representative position of the opening based on the shape contour; a determination unit for determining, with respect to a closing pass in which the opening is closed by the deposited weld bead formed based on the stacking condition, whether the closing of the opening is successful or not based on at least any one of a comparison between the space amount and a design value of the weld bead shape, a comparison between the information of the representative position and a target position of the deposited weld bead included in the stacking condition, and whether a root weld bead can be formed; as well as A correction unit corrects the lamination condition of the closing pass when it is determined that the opening cannot be closed by the closing pass.

9. A program for executing a control step of a stacking molding device having a robot for moving a welding torch and stacking weld beads formed by the tip of the welding torch to mold a molded object, in, The program is used to make the computer execute the following steps: acquiring design values ​​of lamination conditions and weld bead shape of the weld bead formed by movement of the welding torch; measuring the shapes of an opening defined between the weld beads formed based on the lamination conditions or between the weld beads and a surrounding member and the surroundings of the opening, and obtaining a shape contour including the opening; determining a spatial amount representing a size of a space of the opening and a representative position of the opening according to the shape contour; Regarding a closing pass for closing the opening portion by a deposited weld bead formed based on the stacking condition, whether the closing of the opening portion is successful or not is determined based on at least one of a comparison between the space amount and a design value of the weld bead shape, a comparison between the information of the representative position and a target position of the deposited weld bead included in the stacking condition, and whether a root weld bead can be formed; as well as When it is determined that the opening cannot be closed by the closing pass, the stacking condition of the closing pass is corrected.

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