Stacked manufacturing method

Abstract

In the process of forming a stacked object based on a stacked track plan, the shape profile of the deposited weld bead that has been set is measured by a non-contact shape sensor that is provided integrally with a torch at the front end axis of a robot. First geometric information of the weld bead shape is extracted from the shape profile and the aiming position of the torch, second geometric information corresponding to the first geometric information is extracted from the stacked track plan, and the deviation amount between the first geometric information and the second geometric information is calculated. Based on the deviation amount, at least one of the bead height and the bead width of the deposited weld bead specified in the stacked track plan is changed to update the stacked track plan, and the welding conditions are changed according to the update result of the stacked track plan.

Description

Technical Field

[0001] The present invention relates to a layered manufacturing method. Background Art

[0002] Development of control technology for a welding robot to shape a layered structure including multi-layered deposited weld beads is underway (for example, refer to Patent Documents 1 and 2, and Non-Patent Document 1).

[0003] Patent Document 1 describes the following method: In the case of welding a construction iron column, the shape of the already welded deposited weld bead is measured in real time by a laser sensor, and welding conditions are selected from a database based on the measured bead shape to adjust the aiming position of the welding torch, welding current, welding voltage, etc.

[0004] Non-Patent Document 1 describes the following method: In layered manufacturing based on a molten line, the welding voltage and welding speed are controlled according to the bead shape measured by a laser sensor to adjust the height and width of the formed deposited weld bead.

[0005] Patent Document 2 describes a method for adjusting the aiming position of the formation of the next weld bead during multi-layer welding. In this method, the shape of the deposited weld bead formed on a flat plate is measured, and a bead shape approximation function is obtained based on the measurement result. Then, using this bead shape approximation function, a bead shape prediction function for the deposited weld bead formed in the case where there are inclined wall plates on both ribs of the weld bead is obtained. It is described that according to the obtained bead shape prediction function, the aiming position of the weld bead formation is set to either the position of the minimum height of the weld bead or the position of the intersection of the weld bead and the inclined wall plate.

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Patent Laid-Open No. 9-182962

[0009] Patent Document 2: Japanese Patent Laid-Open No. 63-84776

[0010] Non-Patent Documents

[0011] Non-Patent Document 1: Han Q., Li Y., Zhang G. (2018) Online Control of Deposited Geometry of Multi-layer Multi-bead Structure for Wire and Arc Additive Manufacturing. In: Chen S., Zhang Y., Feng Z. (eds) Transactions on Intelligent Welding Manufacturing. Transactions on Intelligent Welding Manufacturing. Springer, Singapore Summary of the Invention

[0012] -Problems to be Solved by the Invention-

[0013] As described above, in order to manufacture a laminated object with high precision, it is necessary to correctly control the width and height of each deposited bead. For this purpose, as in Patent Document 1 and Non-Patent Document 1, when measuring the shape of the formed deposited bead and performing feedback control on the bead formation position, welding conditions, etc. in the next process, in order to shorten the production cycle time of the process, real-time and high-speed measurement is sought. However, generally, when using a laser sensor to measure the bead shape, the deviation of the detection value becomes large due to the light reception sensitivity of the sensor, the linearity of the bead, etc. Therefore, it takes time to perform stable measurement, and it is difficult to achieve high speed.

[0014] In addition, when controlling the tip position of the welding torch to form a deposited bead, in ordinary groove welding, the groove can be used for high-precision positioning. However, in the case of forming a laminated object by stacking laminated objects, there is no absolute positioning reference such as a groove. Therefore, it is impossible to obtain an approximate function of the bead shape with the position of the inclined side plates arranged on both ribs of the bead as a reference as in Patent Document 2. In addition, the approximate calculation of the bead shape becomes complicated, and the approximation accuracy is also reduced, resulting in a reduction in the accuracy of the predicted bead shape. Furthermore, the formed deposited bead also varies depending on conditions such as the protruding length of the wire (filler material) protruding from the tip of the welding torch and the proximity to the surrounding beads. Therefore, there is a deviation in the aiming position of bead formation, or the welding becomes unstable due to the adhesion of spatter.

[0015] For this reason, an object of the present invention is to provide a laminated manufacturing method that can correctly obtain the aiming position of bead formation and can manufacture a laminated object with high precision.

[0016] -Means for Solving the Problems-

[0017] The present invention includes the following structures.

[0018] (1) A layer forming method, in which a welding bead that melts and solidifies a filler material is laminated while moving a welding torch mounted on the front end shaft of a robot, the layer forming method including:

[0019] In the process of forming the deposition bead according to a layer forming track plan that defines the aiming position of the welding torch and the shape of the deposition bead to form a layer formed object, a step of measuring the shape profile of the established deposition bead by a non-contact shape sensor integrally provided with the welding torch on the front end shaft of the robot;

[0020] A step of extracting first geometric information of the bead shape from the shape profile and the aiming position of the welding torch;

[0021] A step of extracting second geometric information corresponding to the first geometric information from the layer forming track plan and calculating a deviation amount between the first geometric information and the second geometric information;

[0022] According to the deviation amount, changing at least one of the bead height and the bead width at a cross section orthogonal to the bead length direction of the deposition bead defined in the layer forming track plan, thereby updating the layer forming track plan; and

[0023] A step of changing welding conditions according to the update result of the layer forming track plan,

[0024] The first geometric information and the second geometric information include at least any one of the following information: geometric feature points near the aiming position of the welding torch, the bead height, the bead width, the bead cross-sectional area of the deposition bead, and a cross-sectional shape approximate curve representing the outer shape of the bead;

[0025] The geometric feature points include any of the following:

[0026] The vertex of the convex shape of the established deposition bead;

[0027] The end points of a narrow portion formed by the outer surface of the bead being recessed inward between the deposition bead and other deposition beads adjacent to the deposition bead;

[0028] The point where the width direction end of the deposition bead intersects the lower layer on which the deposition bead is formed.

[0029] (2) A layer forming method, in which a welding bead that melts and solidifies a filler material is laminated while moving a welding torch mounted on the front end shaft of a robot, the layer forming method including:

[0030] In the process of forming a deposited bead based on a stacking track plan that defines the aiming position of the torch and the shape of the deposited bead to form a stacked object, a step of measuring the shape profile of the deposited bead that has been set by a non-contact shape sensor integrally provided with the torch on the front end axis of the robot;

[0031] A step of extracting first geometric information of the bead shape from the shape profile and the aiming position of the torch;

[0032] A step of extracting second geometric information corresponding to the first geometric information from the stacking track plan and calculating the deviation amount between the first geometric information and the second geometric information;

[0033] A step of updating the stacking track plan by changing at least one of the bead height and the bead width at a cross-section orthogonal to the bead length direction of the deposited bead defined in the stacking track plan according to the deviation amount; and

[0034] A step of changing the welding conditions according to the update result of the stacking track plan,

[0035] The shape profile is a profile obtained by performing a projection transformation in a plane including the axis of the torch, and the plane is inclined by a predetermined angle from a plane parallel to the detection direction of the deposited bead based on the non-contact shape sensor.

[0036] (3) A stacking forming method in which while moving a torch mounted on the front end axis of a robot, a deposited bead in which a filler material is melted and solidified is stacked, and the stacking forming method includes:

[0037] In the process of forming a deposited bead based on a stacking track plan that defines the aiming position of the torch and the shape of the deposited bead to form a stacked object, a step of measuring the shape profile of the deposited bead that has been set by a non-contact shape sensor integrally provided with the torch on the front end axis of the robot;

[0038] A step of extracting first geometric information of the bead shape from the shape profile and the aiming position of the torch;

[0039] A step of extracting second geometric information corresponding to the first geometric information from the stacking track plan and calculating the deviation amount between the first geometric information and the second geometric information;

[0040] A step of updating the stacking track plan by changing at least one of the bead height and the bead width at a cross-section orthogonal to the bead length direction of the deposited bead defined in the stacking track plan according to the deviation amount; and

[0041] A process of changing welding conditions according to the update result of the stacked track plan

[0042] Taking the difference between the cross-sectional area of the target shape of the deposited bead specified in the stacked track plan at the orthogonal cross-section in the length direction of the deposited bead and the cross-sectional area of the deposited bead obtained from the shape profile as the deviation amount

[0043] (4) A stacked manufacturing method, while moving a torch installed at the front end axis of a robot, stacking deposited beads in which a filler material is melted and solidified, the stacked manufacturing method includes:

[0044] In the process of forming the deposited bead based on a stacked track plan that defines the aiming position of the torch and the shape of the deposited bead to manufacture a stacked object, a process of measuring the shape profile of the deposited bead that has been set by a non-contact shape sensor integrally provided with the torch on the front end axis of the robot

[0045] A process of extracting the first geometric information of the bead shape from the shape profile and the aiming position of the torch

[0046] A process of extracting the second geometric information corresponding to the first geometric information from the stacked track plan and calculating the deviation amount between the first geometric information and the second geometric information

[0047] According to the deviation amount, changing at least one of the bead height and bead width at the cross-section orthogonal to the bead length direction of the deposited bead specified in the stacked track plan, thereby updating the stacked track plan; and

[0048] A process of changing welding conditions according to the update result of the stacked track plan

[0049] Obtaining a cross-sectional shape approximation curve that approximates the shape profile at the orthogonal cross-section in the length direction of the deposited bead to a curve model by regression calculation

[0050] Taking the difference between the cross-sectional area surrounded by the cross-sectional shape approximation curve and the cross-sectional area of the target shape of the deposited bead specified in the stacked track plan as the deviation amount

[0051] (5) A stacked manufacturing method, while moving a torch installed at the front end axis of a robot, stacking deposited beads in which a filler material is melted and solidified, the stacked manufacturing method includes:

[0052] In the process of forming a deposited bead based on a stacking track plan that defines the aiming position of the torch and the shape of the deposited bead to shape a stacked object, a step of measuring the shape profile of the deposited bead that has been set by a non-contact shape sensor integrally provided with the torch on the front end axis of the robot;

[0053] A step of extracting first geometric information of the bead shape from the shape profile and the aiming position of the torch;

[0054] A step of extracting second geometric information corresponding to the first geometric information from the stacking track plan and calculating the deviation amount between the first geometric information and the second geometric information;

[0055] A step of updating the stacking track plan by changing at least one of the bead height and the bead width at a cross-section orthogonal to the bead length direction of the deposited bead defined in the stacking track plan according to the deviation amount; and

[0056] A step of changing the welding conditions according to the update result of the stacking track plan,

[0057] Let the cross-sectional shape approximation curve that approximates the shape profile at a cross-section orthogonal to the length direction of the deposited bead to a curve model by regression calculation be such that the cross-sectional area surrounded by the cross-sectional shape approximation curve is equal to the cross-sectional area of the target shape of the deposited bead defined in the stacking track plan,

[0058] Let the difference between the position of the topmost part of the cross-sectional shape approximation curve and the target formation position of the deposited bead be the deviation amount.

[0059] (6) A stacking shaping method, while moving a torch installed on the front end axis of a robot, stacking a deposited bead in which a filler material is melted and solidified, the stacking shaping method includes:

[0060] In the process of forming a deposited bead based on a stacking track plan that defines the aiming position of the torch and the shape of the deposited bead to shape a stacked object, a step of measuring the shape profile of the deposited bead that has been set by a non-contact shape sensor integrally provided with the torch on the front end axis of the robot;

[0061] A step of extracting first geometric information of the bead shape from the shape profile and the aiming position of the torch;

[0062] A step of extracting second geometric information corresponding to the first geometric information from the stacking track plan and calculating the deviation amount between the first geometric information and the second geometric information;

[0063] A process of updating the stacked track plan by changing at least one of the bead height and the bead width at a cross-section orthogonal to the bead length direction of the deposited bead as specified in the stacked track plan according to the deviation amount; and

[0064] A process of changing the welding conditions according to the update result of the stacked track plan,

[0065] Obtaining a cross-sectional shape approximation curve that approximates the shape profile at a cross-section orthogonal to the length direction of the deposited bead to a curve model through regression calculation,

[0066] Taking the difference between the height of an arbitrary point on the cross-sectional shape approximation curve and the height at the corresponding position in the target shape of the deposited bead specified in the stacked track plan as the deviation amount.

[0067] (7) A stacked manufacturing method in which a deposited bead obtained by melting and solidifying a filler material is stacked while moving a welding torch mounted on the front end shaft of a robot, the stacked manufacturing method including:

[0068] In the process of forming a stacked object by forming the deposited bead based on a stacked track plan that specifies the aiming position of the welding torch and the shape of the deposited bead, a process of measuring the shape profile of the deposited bead that has been set by a non-contact shape sensor integrally provided with the welding torch on the front end shaft of the robot;

[0069] A process of extracting first geometric information of the bead shape from the shape profile and the aiming position of the welding torch;

[0070] A process of extracting second geometric information corresponding to the first geometric information from the stacked track plan and calculating the deviation amount between the first geometric information and the second geometric information;

[0071] A process of updating the stacked track plan by changing at least one of the bead height and the bead width at a cross-section orthogonal to the bead length direction of the deposited bead as specified in the stacked track plan according to the deviation amount; and

[0072] A process of changing the welding conditions according to the update result of the stacked track plan,

[0073] Setting the cross-sectional shape approximation curve that approximates the shape profile at a cross-section orthogonal to the length direction of the deposited bead to a curve model through regression calculation such that the difference between the height of an arbitrary point on the cross-sectional shape approximation curve and the height at the corresponding position in the target shape of the deposited bead specified in the stacked track plan becomes smaller,

[0074] The difference between the position at the topmost part of the approximate curve of the cross-sectional shape and the target formation position of the deposited bead is used as the deviation amount.

[0075] -Advantages of the Invention-

[0076] According to the present invention, the aiming position for bead formation can be accurately obtained, and a laminated object with high precision can be manufactured. BRIEF DESCRIPTION OF THE DRAWINGS

[0077] Figure 1 is a structural diagram of a manufacturing apparatus for a laminated object.

[0078] Figure 2 is a flowchart showing steps of determining the torch aiming position and welding conditions for bead formation based on a lamination track plan, welding conditions, and the shape measurement result of a deposited bead.

[0079] Figure 3 is a schematic diagram showing a case of forming a deposited bead.

[0080] Figure 4 is a schematic explanatory view showing the cross-sectional shape of a deposited bead and the position of a torch when observing a welding position from the downstream side in the welding direction.

[0081] Figure 5 is showing along Figure 4 a schematic explanatory view of a case of newly forming a deposited bead along a provided deposited bead shown.

[0082] Figure 6 is an explanatory view schematically showing the basic change steps of changing the lamination track plan and welding conditions for forming a new deposited bead according to the shape of a provided deposited bead, step by step as (A) to (C).

[0083] Figure 7 is a cross-sectional view showing the shape of a deposited bead.

[0084] Figure 8 is an explanatory view schematically showing the first change steps of changing the lamination track plan and welding conditions for forming a new deposited bead according to the shape of a provided deposited bead, step by step as (A) to (C).

[0085] Figure 9 is an explanatory view schematically showing the second change steps of changing the lamination track plan and welding conditions for forming a new deposited bead according to the shape of a provided deposited bead, step by step as (A) to (C).

[0086] Figure 10It is an explanatory diagram that stepwise shows the third change step of changing the stacking track plan and welding conditions for forming a newly established deposited weld bead according to the shape of the established deposited weld bead, represented as (A) to (C).

[0087] Figure 11 It is an explanatory diagram that stepwise shows the fourth change step of changing the stacking track plan and welding conditions for forming a newly established deposited weld bead according to the shape of the established deposited weld bead, represented as (A) and (B).

[0088] Figure 12 It is an explanatory diagram that stepwise shows the fifth change step of changing the stacking track plan and welding conditions for forming a newly established deposited weld bead according to the shape of the established deposited weld bead, represented as (A) and (B).

[0089] Figure 13 It is an explanatory diagram showing a situation where a deposited weld bead for the lower layer and a deposited weld bead for the upper layer are formed by a torch provided in a welding robot, and the shape of the weld bead is measured by a laser shape sensor.

[0090] Figure 14 It is an explanatory diagram showing changes in the welding state when an error occurs in the measured weld bead shape, represented as (A) and (B).

[0091] Figure 15 It is a graph schematically showing the change characteristics of the welding current with respect to the protruding length of the filler material. Detailed implementation mode

[0092] Hereinafter, with reference to the accompanying drawings, the implementation modes of the present invention will be described in detail.

[0093] Here, the steps of manufacturing a laminated shaped object including multiple layers of deposited weld beads using a laminated shaping device that melts and solidifies a filler material to form deposited weld beads will be described.

[0094] Figure 1 It is a structural diagram of a manufacturing device for a laminated shaped object.

[0095] The laminated shaping device 100 of this structure includes a shaping device 11, a controller 13 that performs overall control of the shaping device 11, and a power supply device 15.

[0096] The shaping device 11 has: a welding robot 19 having a torch 17 provided at the front end shaft, and a filler material supply unit 21 that supplies a filler material (welding wire) M to the torch 17. The shaping device 11 forms a deposited weld bead B while moving the torch 17 by driving the welding robot.

[0097] In addition, a non-contact shape sensor that moves integrally with the welding torch 17 is provided on the front end shaft of the welding robot 19. As the non-contact shape sensor, a laser shape sensor 23 that detects a three-dimensional shape by the light cutting method, the pattern projection method, etc. is used here, but the detection method is not limited.

[0098] The welding robot 19 is a multi-joint robot that supports continuously supplying the filler material M to the welding torch 17 mounted on the front end shaft of the robot arm. The position and posture of the welding torch 17 can be arbitrarily set three-dimensionally within the range of the degrees of freedom of the robot arm.

[0099] The welding torch 17 has a protection nozzle (not shown), and a shielding gas is supplied from the protection nozzle. As the arc welding method, it can be any of the consumable electrode type such as covered arc welding, carbon dioxide gas arc welding, etc., and the non-consumable electrode type such as TIG welding, plasma arc welding, etc., and is appropriately selected according to the fabricated laminated object.

[0100] For example, in the case of the consumable electrode type, a contact tip is disposed inside the protection nozzle, and the filler material M for supplying the melting current is held by the contact tip. The welding torch 17 holds the filler material M, and an arc is generated from the front end of the filler material M in a shielding gas atmosphere. The filler material M is fed from the filler material supply unit 21 to the welding torch 17 through a feeding mechanism (not shown) mounted on the robot arm or the like. And if the welding torch 17 is moved and the continuously fed filler material M is melted and solidified, a molten solid of the filler material M, that is, a linear weld bead B, is formed on the base portion 25.

[0101] The base portion 25 includes a metal plate such as a steel plate, and a base portion that is substantially larger than the bottom surface (the lowermost surface) of the laminated object W is basically used. In addition, the base portion 25 is not limited to a plate shape, and may also be a base of other shapes such as a block, a rod, or a cylinder.

[0102] As the filler material M, all commercially available welding wires can be used. For example, it is possible to use specified welding wires such as solid wires for MAG welding and MIG welding (JIS Z3312) for low carbon steel, high strength steel, and low temperature steel, and flux cored wires for arc welding (JIS Z3313) for low carbon steel, high strength steel, and low temperature steel.

[0103] The controller 13 includes: a CAD / CAM unit 31, a trajectory calculation unit 33, a storage unit 35, and a control unit 37 to which they are connected.

[0104] The CAD / CAM unit 31 is input with the shape data (CAD data, etc.) of the laminated object to be fabricated, and collaborates with the trajectory calculation unit 33 to create a laminated trajectory plan representing the fabrication steps of the laminated object. This laminated trajectory plan is analyzed and solved based on the input shape data, various conditions such as its shape, material, and input heat, and an appropriate algorithm so that effective lamination can be achieved.

[0105] In the creation of the laminated trajectory plan, first, the shape data is divided into multiple layers, and layer shape data representing the shape of each layer is generated. Then, based on the generated layer shape data, the movement trajectory of the torch 17 and the welding conditions are determined, and a drive program for the welding robot 19 and the power supply device 15 for forming the deposited weld bead B is generated. This drive program implements the actions corresponding to the laminated trajectory plan. Various data of the drive program and the welding conditions are stored in the storage unit 35.

[0106] The control unit 37 drives the welding robot 19, the power supply device 15, etc. by executing the drive program stored in the storage unit 35 to form the deposited weld bead B. That is, the control unit 37 drives the welding robot 19 to move the torch 17 along the set trajectory of the torch 17, and melts the filler material M protruding from the tip of the torch 17 by an electric arc according to the set welding conditions to form the deposited weld bead B. Then, the following is repeated: making multiple deposited weld beads B adjacent to each other on the base part 25 to form a deposited weld bead layer 27, and laminating the next deposited weld bead layer 27 on top of this deposited weld bead layer 27. In this way, the laminated object W of the desired shape is fabricated.

[0107] In addition, when the control unit 37 moves the torch 17 for bead formation, it measures the shape of the already formed deposited weld bead B using the laser shape sensor 23. The measurement based on the laser shape sensor 23 can also be performed outside of welding.

[0108] <Modification of the laminated trajectory plan and welding conditions>

[0109] Here, in the laminated fabrication apparatus 100 of this structure, the trajectory calculation unit 33 obtains the aiming position of the torch 17 (hereinafter referred to as the torch aiming position) for forming the deposited weld bead to be formed thereafter and the welding conditions during the lamination process based on the created laminated trajectory plan, the welding conditions, and the shape measurement results of the already formed deposited weld bead, and changes the laminated trajectory plan and the welding conditions as needed.

[0110] Figure 2 It is a flowchart showing the steps of determining the torch aiming position and the welding conditions for bead formation based on the laminated trajectory plan, the welding conditions, and the shape measurement results of the deposited weld bead.

[0111] First, a deposited bead is formed in accordance with a stacked track plan created based on the input shape data (S1).

[0112] Figure 3 It is a schematic diagram showing a case where a deposited bead B is formed.

[0113] The welding robot 19 is driven to form the deposited bead B while moving the torch 17. At this time, the shape of the already formed deposited bead B is measured at a position downstream of the torch aiming position P in the welding direction WD by a laser shape sensor 23 provided integrally with the front end shaft of the welding robot 19 and the torch 17.

[0114] The laser shape sensor 23 includes a laser irradiation unit 23A and a detection sensor 23B. For example, in the case of measurement by the light interruption method, slit light L1 is irradiated from the laser irradiation unit 23A, and the reflected light L2 from the already formed deposited bead B is detected by the detection sensor 23B which is an image sensor. In the two-dimensional image detected by the detection sensor 23B, a pattern corresponding to the height of the deposited bead is included, and the shape of the deposited bead is obtained based on this pattern. Since the description of the specific shape detection method is well-known, it is omitted here.

[0115] Figure 4 It is a schematic explanatory diagram showing the cross-sectional shape of the deposited bead B and the position of the torch 17 when observing the welding position from the downstream side in the welding direction.

[0116] In this case, around the torch aiming position P where the deposited bead is formed, there are lower deposited beads B1, B2, B3, and a deposited bead B4 formed above the deposited bead B1.

[0117] The laser shape sensor 23 irradiates slit light L1, detects the reflected light from the deposited beads B1 to B4, and obtains the shape of each deposited bead around the front end of the torch. Figure 4 In, based on the shape of each measured deposited bead, shape information including the vertex P1 of the deposited bead B2 located directly below the axis Ax of the torch 17 and the narrow point P2 where the surface of the deposited bead B4 arranged on the side of the torch 17 is connected to the surface of the deposited bead B2 is obtained.

[0118] Figure 5 It shows along Figure 4 A schematic explanatory diagram of the case of newly forming a deposited bead along the already formed deposited bead shown.

[0119] According to Figure 4 The shape of the already formed deposited beads B1 to B4 around the front end of the torch 17 shown, determine Figure 5The torch aiming position of the subsequently formed deposited bead B5 shown, the welding conditions during bead formation, etc. In the case where there are differences between the set contents of the determined torch aiming position and welding conditions, etc. and the set contents of the torch movement trajectory and welding conditions, etc. of the original layer stacking track plan, the layer stacking track plan and welding conditions are changed.

[0120] Here, the change steps of the above layer stacking track plan and welding conditions are described in detail.

[0121] <Basic change steps>

[0122] Figure 6 It is an explanatory diagram that stepwise shows the basic change steps (A) to (C) for changing the layer stacking track plan and welding conditions for forming a newly established deposited bead according to the shape of the already established deposited bead. Additionally, Figure 6 (A) to (C) show the shapes at the orthogonal cross-section in the length direction of the deposited bead.

[0123] First, as shown in (A) of Figure 6 , the shape profile Pf(S2) of the already established deposited bead is measured by the laser shape sensor 23. Here, a measurement example of one deposited bead is simply shown. The shape profile Pf can be a straight line, curve, etc. that interpolates between the measurement points in addition to the line connecting multiple measurement points.

[0124] Then, referring to the layer stacking track plan, the torch aiming position P for the measured deposited bead is extracted. Based on the measured shape profile Pf and the information of the extracted torch aiming position P, the first geometric information of the bead shape (S3) is extracted. The so-called first geometric information refers to information including the shape profile Pf of the deposited bead represented in the sensor coordinate system based on the laser shape sensor 23 and the torch aiming position P represented in the robot coordinate system of the welding robot 19 (refer to Figure 1 ) after coordinate transformation to represent them in the same coordinate system.

[0125] Here, in order to make the torch aiming position P correspond to the shape profile Pf, the following processing is performed. First, at the torch tip position in the robot coordinates of the welding robot, the welding position is obtained considering the inclination (posture) of the torch 17. That is, the set value of the distance ΔL from the torch tip to the already established deposited bead directly below it (refer to Figure 4 ) is offset to the torch tip position. The offset position becomes the welding position of the torch 17, and this position is defined as the torch aiming position P. Then, the torch aiming position P in the robot coordinate system is coordinate-transformed into the sensor coordinate system. Thus, the shape profile Pf in the sensor coordinate system and the torch aiming position P are made to correspond in the same coordinate system.

[0126] Next, extract second geometric information corresponding to the above-mentioned first geometric information to be extracted (S4). Here, the so-called second geometric information is information on the target shape of the deposited bead and the torch aiming position in the layer stacking track plan used when forming the deposited bead for measuring the shape of the above-mentioned bead.

[0127] Figure 6 (B) of represents when forming Figure 6 the deposited bead with the shape profile Pf shown in (A) above, the target shape Ts of the deposited bead and the torch aiming position P determined by the layer stacking track plan.

[0128] Then, compare the first geometric information and the second geometric information, and calculate the deviation amount between the two (S5). That is, obtain the deviation amount between the shape of the measured deposited bead and the target shape.

[0129] Figure 6 (C) of represents Figure 6 the height deviation amount ΔH between the shape profile Pf shown in (A) above and Figure 6 the target shape Ts shown in (B) above. The deviation amount ΔH is the difference in height between the vertex of the shape profile Pf and the vertex of the target shape Ts, and the vertex of the shape profile Pf is determined using the height of the measurement points near the vertex. In addition, here the shape profile Pf and the target shape Ts are arranged so that each torch aiming position P is at the same position.

[0130] Change at least one of the bead height Bh and the bead width Bw in the target shape Ts of the deposited bead B determined by the layer stacking track plan (refer to Figure 7 ) so that the deviation amount ΔH of this height becomes smaller, and update the layer stacking track plan (S6). The update of the layer stacking track plan here can also change various parameters such as the torch aiming position and the bead cross-sectional area in addition to the change of the bead height Bh and the bead width Bw.

[0131] In addition, according to the update result of the layer stacking track plan, change the welding conditions (S7). As the welding conditions, list the position and posture of the torch, welding speed, welding voltage, welding current, feeding speed of the filler material, etc. Change at least one of these, or combine any two or more to change.

[0132] Then, form a deposited bead with the changed layer stacking track plan and welding conditions (S8). Repeat the above process until the layer-built object is completed (S9).

[0133] The front-end position of the welding torch, the position of the deposited weld bead, and the shape of the already deposited weld bead need to be grasped at all times, and this can be carried out only for the required parts or by prioritizing any one of the above. For example, in the case of manufacturing a laminated object having a deposited weld bead forming a frame portion and a deposited weld bead filling the inside of the frame portion, in the shaping of the frame portion where relatively thin deposited weld beads are laminated, it is necessary to precisely adjust the positions of the respective weld beads, so the above positions and shapes are grasped at all times. On the other hand, in the shaping of filling the inside of the frame portion, it is necessary to fill the inside of the frame without gaps, so the grasping of the cross-sectional area of the deposited weld bead is prioritized over the adjustment of the welding torch position.

[0134] Figure 7 It is a cross-sectional view showing the shape of the deposited weld bead.

[0135] Preferably, the above-mentioned first geometric information and second geometric information include at least any one of the following information: bead height Bh, bead width Bw, bead cross-sectional area A at a cross-section orthogonal to the bead length direction, geometric feature points near the torch aiming position, and a cross-sectional shape approximation curve representing the bead outer shape of the deposited weld bead B detailed later.

[0136] Here, the so-called geometric feature points, as Figure 4 shown are feature points extracted from the already deposited weld bead disposed around the welding torch 17. Specifically, they include: the vertex P1 of the convex shape of the already deposited weld bead B2, and the narrow point P2 formed by the inward depression of the weld bead outer surface between the other deposited weld bead B4 adjacent to the weld bead B2. It also includes: in the case before the formation of the weld bead B3, among the pair of width-direction end points P3a, P3b of the weld bead B2, the point P3a that intersects with the lower layer (here the base portion 25) where the weld bead B2 is formed.

[0137] In addition, for the already deposited weld bead, the cross-sectional area of the weld bead can also be determined according to the welding conditions during weld bead formation. The weld bead cross-sectional area A is equal to the cross-sectional area of the metal material newly input for weld bead formation. For example, the weld bead cross-sectional area A varies according to the minor axis of the elliptical model and the height from the base (lower layer) when approximating the deposited weld bead with an elliptical model. In addition, the so-called cross-sectional area here refers to the volume per unit length of the deposited weld bead and is expressed by the following formula (1).

[0138] A = dw 2 Fwπ / 4F…(1)

[0139] dw: diameter of the filler material [mm]

[0140] Fw: feed rate of the filler material [mm / min]

[0141] F: torch feed rate [mm / min]

[0142] On the other hand, for the cross-sectional area of the subsequently formed deposited bead, for example, an arc centered on the torch aiming position P is used as the outer contour line of the deposited bead, and the area inside the arc is obtained as the cross-sectional area of the deposited bead. However, the calculation method of the cross-sectional area is not limited to this.

[0143] According to this layer-by-layer forming method, the layer-by-layer track plan is updated based on the difference in bead height between the layer-by-layer track plan and the actual formation result of the deposited bead, and the welding conditions are changed accordingly, so that the next deposited bead can be formed with high precision. In addition, since the deposited bead is formed based on the layer-by-layer track plan that reflects the actual bead formation result, it is possible to achieve forming with an accuracy on the order of 0.1 mm, for example.

[0144] Next, the change steps of other layer-by-layer track plans and welding conditions based on the above basic change steps will be described in sequence.

[0145] <The First Change Step>

[0146] Figure 8 The first change step of changing the layer-by-layer track plan and welding conditions for forming the newly established deposited bead according to the shape of the established deposited bead is shown in (A) to (C) in stages in the explanatory drawing.

[0147] Let Figure 8 the cross-sectional area of the shape profile Pf at the orthogonal cross-section in the length direction of the deposited bead shown in (A) be Apf, and let Figure 8 the cross-sectional area of the target shape Ts of the deposited bead determined by the layer-by-layer track plan shown in (B) be Ats.

[0148] In this change step, as shown in (C), the difference Df between the cross-sectional area Apf of the shape profile Pf and the cross-sectional area Ats of the target shape Ts is set as the deviation amount, and the layer-by-layer track plan is changed to make this deviation amount smaller. Then, according to the updated layer-by-layer track plan, the welding conditions are changed as needed. Figure 8

[0149] According to this step, since the area difference between the shape profile Pf and the target shape Ts is made smaller, it is assumed that even when there is a locally large shape difference between the shape profile Pf and the target shape Ts, it will not be greatly affected by this local shape difference, and an appropriate reduction of the deviation amount can be achieved.

[0150] <The Second Change Step>

[0151] Figure 9 ​This is an explanatory diagram that shows the second change step of changing the layer stacking track plan and welding conditions for forming a newly established deposited bead according to the shape of the already set deposited bead, which is presented stage by stage as (A) to (C).

[0152] In this change step, as Figure 9 shown in (A), a cross-sectional shape approximation curve Cpf that approximates the shape profile to a curve model through regression calculation is obtained. As the curve model, any curve such as a parabola, a function of degree three or higher, or a spline curve can be used. For example, using a curve model of Z = aY2 + bY + c (where a, b, and c are coefficients), fitting is performed with the measured shape profile Pf(Yj, Zj). Fitting can adopt known methods such as the least squares method and the steepest descent method.

[0153] Then, as Figure 9 shown in (C), the torch aiming position P is made consistent so that the cross-sectional shape approximation curve Cpf coincides with the target shape Ts shown in Figure 9 (B), thereby obtaining the distribution of the height deviation amount ΔH generated between the cross-sectional shape approximation curve and the target shape. The layer stacking track plan is changed so that this deviation amount ΔH becomes smaller. Then, according to the updated layer stacking track plan, the welding conditions are changed as needed.

[0154] According to this step, since the shape profile can be approximated to a curve model, the bead shape can be grasped more precisely, and the bead center position and bead height of the shape profile can be obtained more correctly. Thus, the next deposited bead to be formed can be formed with higher precision.

[0155] <The Third Change Step>

[0156] Figure 10 This is an explanatory diagram that shows the third change step of changing the layer stacking track plan and welding conditions for forming a newly established deposited bead according to the shape of the already set deposited bead, which is presented stage by stage as (A) to (C).

[0157] In this change step, as Figure 10 shown in (A), a cross-sectional shape approximation curve Cpf that approximates the shape profile to a curve model through regression calculation is obtained, such that the cross-sectional area Ac of the region surrounded by this cross-sectional shape approximation curve Cpf is Figure 10is equal to the cross-sectional area Ats of the target shape Ts shown in (B). In this calculation, for example, the constrained least squares method can be adopted. The constrained least squares method is a method of approximation processing with the constraint that the cross-sectional area Ac formed by the cross-sectional shape approximation curve Cpf as the model curve is made to coincide with the cross-sectional area Ats predetermined by the layer stacking track plan when minimizing the objective function representing the error amount.

[0158] Then, the layer stacking track plan is changed so that Figure 10 the top Pa of the cross-sectional shape approximation curve Cpf where the cross-sectional area Ac is equal to the cross-sectional area Ats as shown in (C) coincides with the top Pb of the target shape Ts, that is, the target formation position of the weld bead. That is, the target formation position of the weld bead is corrected so that the top Pa of the cross-sectional shape approximation curve corresponding to the formed weld bead coincides with the top Pb of the target shape Ts. Then, according to the updated layer stacking track plan, the welding conditions are changed as needed.

[0159] According to this step, by the simple process of making the top Pa of the cross-sectional shape approximation curve coincide with the top Pb of the target shape Ts, the next formed weld bead can be formed with high precision.

[0160] <The Fourth Change Step>

[0161] Figure 11 is an explanatory diagram showing the fourth change step of changing the layer stacking track plan and welding conditions for forming a new weld bead according to the shape of the set weld bead, shown in (A) and (B) in stages.

[0162] In this change step, as Figure 11 shown in (A), the cross-sectional shape approximation curve Cpf whose shape profile is approximated to the curve model is obtained by regression calculation.

[0163] Next, as Figure 11 shown in (B), the target formation position of the weld bead is corrected so that: for the entire cross-sectional shape approximation curve Cpf, the difference ΔH, that is, the deviation amount, between the height of an arbitrary point on the cross-sectional shape approximation curve Cpf and the height of the outer contour line of the target shape Ts corresponding to the arbitrary point becomes smaller. Then, according to the updated layer stacking track plan, the welding conditions are changed as needed.

[0164] According to this step, since the deviation amount ΔH is determined using the cross-sectional shape approximation curve Cpf, compared with the case of determining the deviation amount ΔH using the Figure 6 shown shape profile, the correction with high precision can be stably performed, and a weld bead with higher precision can be formed.

[0165] <Fifth change step>

[0166] Figure 12 The fifth change step of changing the stacking track plan and welding conditions for forming the newly established deposited bead according to the shape of the established deposited bead is illustrated step by step as (A) and (B).

[0167] In this change step, as shown in (A) of Figure 12 , the cross-sectional shape approximation curve Cpf that approximates the shape profile to the curve model by regression calculation is changed so that Figure 12 , as shown in (B) of , the deviation amount ΔH, which is the difference between the height of any point on the cross-sectional shape approximation curve Cpf and the height of the outer contour line of the target shape Ts corresponding to the any point, becomes smaller.

[0168] In addition, the stacking track plan is changed so that the position of the cross-sectional shape approximation curve Cpf coincides with the target formation position of the deposited bead as the target shape Ts. That is, the stacking track plan is changed so that the topmost part Pa of the cross-sectional shape approximation curve corresponding to the formed deposited bead coincides with the topmost part Pb of the target shape Ts. Then, according to the updated stacking track plan, the welding conditions are changed as needed.

[0169] According to this step, the deviation amount ΔH of the bead height can be reduced, and the position in the bead width direction of the cross-sectional shape approximation curve Cpf with the reduced deviation amount ΔH coincides with the target formation position. Therefore, the next formed deposited bead can be formed with higher precision.

[0170] <High-precision of deposited bead>

[0171] Next, a method for forming a deposited bead with higher precision will be described.

[0172] In the above-described embodiment, the deposited bead is formed on the flat substrate portion, but here, the case where the deposited bead is formed on the circumferential surface of the substrate portion will be described.

[0173] Figure 13 It is an explanatory diagram of a case where the lower deposited bead B1 and the upper deposited bead B2 are formed by the torch 17 provided in the welding robot 19, and the bead shape is measured by the laser shape sensor 23.

[0174] The cylindrical substrate portion 25A is centered on the central axis O in Figure 13The shown Rt is rotationally driven, and on the circumferential surface of the outer periphery of the base portion 25A, a deposited weld bead B is formed by the welding torch 17. The laser shape sensor 23 mounted on the welding robot 19 is disposed on the upstream side (downstream side in the welding direction) in the rotational direction of the base portion 25A, and measures the shape of the set deposited weld bead B1.

[0175] The laser shape sensor 23 measures the shape of the deposited weld bead B1 by detecting a two-dimensional image of the reflected light L2. Its shape is the shape at the weld bead cross-section parallel to the reflected light L2 at the measurement point Pm. The reflected light L2 is parallel to the axis of the welding torch 17 (torch axis) Ax. Here, the central angle of the arc connecting Figure 13 the torch aiming position P and the measurement point Pm in the shown base portion 25A is set as θ.

[0176] If the deposited weld bead B2 is formed while rotationally driving the base portion 25A, the deposited weld bead B1 at the measurement point Pm reaches the torch aiming position P. At this time, the shape of the deposited weld bead B1 measured at the measurement point Pm is not the shape at the cross-section including the torch axis Ax, but becomes the shape at the cross-section including the straight line Lm inclined by the angle θ rearward in the welding direction from the torch axis Ax.

[0177] Therefore, projective transformation is performed on the measured shape of the deposited weld bead B1 so that it becomes the shape of the cross-section of the torch axis Ax at the torch aiming position P. Projective transformation is a well-known transformation process for geometrically inclining the angle θ, so the description of the transformation process is omitted.

[0178] Thus, the shape of the deposited weld bead measured at the measurement point Pm is transformed into the cross-section shape at the position corresponding to the torch axis Ax at the torch aiming position P. Thereby, the change of the correct welding track plan can be performed, and the deposited weld bead can be formed with high precision.

[0179] Figure 14 Figures (A) and (B) are explanatory diagrams showing the change of the welding state in the case where an error occurs in the measured weld bead shape.

[0180] As Figure 14 shown in (A) of, if measurement errors occur in the shapes of the set deposited weld beads B2 and B4 near the torch aiming position P, the distances S1 between the deposited weld bead B2 and the torch tip position and S2 between the deposited weld bead B4 and the aiming position P are different from the assumed distances. In this case, as Figure 14 shown in (B) of, the substantial protruding length (exposed length) of the filler material M changes, and thus the arc Arc is displaced according to the distance between the surrounding set deposited weld beads and the filler material M, etc., and the arc Arc becomes unstable. As a result, there is a concern that the shape accuracy of the formed deposited weld bead is reduced.

[0181] Figure 15 This is a graph schematically showing the change characteristics of the welding current with respect to the protruding length of the filler material.

[0182] The change in the protruding length of the filler material M not only causes the generated arc to be unstable, but also affects the welding current. That is, the longer the protruding length is, the smaller the welding current is, and the smaller the formed weld bead is. Therefore, as described above, by accurately measuring the shape of the already formed weld bead, it is possible to suppress the change in welding conditions and form a high-precision weld bead.

[0183] <Shape model of deposited weld bead>

[0184] In the above description, the shape of the weld bead is represented using the weld bead height, weld bead width, weld bead cross-sectional area, and a cross-sectional shape approximation curve representing the weld bead outer shape of the weld bead, but the parameters representing the shape are not limited to these.

[0185] For example, in the literature (BM Berezovskii and AV Stikahin, Optimisation of the formatin of a metal layer in arc deposition, Welding International, 1991, 5 (11), pp. 888-891), the bead width, the height from the base surface to the bead top, the curvature R of the bead top, the contact angle between the deposited bead and the base are used. The weld bead shape is characterized by various parameters such as the distance between the axes of the welding torch positions for forming a pair of adjacent weld beads. In the present stacking forming method, the stacking trajectory plan and welding conditions may be changed using the above parameters.

[0186] Thus, the present invention is not limited to the above-mentioned embodiments, and the combinations of the structures of the embodiments, or changes and applications based on the description in the specification and known technologies by those skilled in the art are also intended by the present invention and are included in the scope of protection.

[0187] As described above, the following matters are disclosed in this specification.

[0188] (1) A stacking forming method for stacking weld beads by melting and solidifying a filler material while moving a welding torch mounted on a front end shaft of a robot, the stacking forming method comprising:

[0189] In the process of forming a deposited bead to shape a laminated object based on a layer stacking track plan that defines the aiming position of the welding torch and the shape of the deposited bead, a process of measuring the shape profile of the deposited bead that has been set by a non-contact shape sensor integrally provided with the welding torch on the front end axis of the robot;

[0190] A process of extracting first geometric information of the bead shape from the shape profile and the aiming position of the welding torch;

[0191] A process of extracting second geometric information corresponding to the first geometric information from the layer stacking track plan and calculating the deviation amount between the first geometric information and the second geometric information;

[0192] A process of updating the layer stacking track plan by changing at least one of the bead height and the bead width at a cross-section orthogonal to the bead length direction of the deposited bead defined in the layer stacking track plan according to the deviation amount; and

[0193] A process of changing the welding conditions according to the update result of the layer stacking track plan.

[0194] According to this layer forming method, since the layer stacking track plan and the welding conditions are changed so that the deviation amount between the first geometric information representing the shape of the formed deposited bead and the second geometric information representing the target shape becomes smaller, it is possible to make the shape of the formed deposited bead more accurately coincide with the target shape.

[0195] (2) In the layer forming method described in item (1), the first geometric information and the second geometric information include at least any one of the following information: geometric feature points near the aiming position of the welding torch, the bead height, the bead width, the bead cross-sectional area of the deposited bead, and the cross-sectional shape approximate curve representing the bead outer shape;

[0196] According to this layer forming method, by using various parameters, it is possible to determine the shape of the deposited bead, which helps to form a more accurate deposited bead.

[0197] (3) In the layer forming method described in item (2), the geometric feature points include any of the following:

[0198] The vertex of the convex shape of the deposited bead that has been set;

[0199] The end points of the narrow part formed by the outer surface of the bead being recessed inward between the deposited bead and other deposited beads adjacent to it;

[0200] The point where the width direction end of the deposited bead intersects the lower layer on which the deposited bead is formed.

[0201] According to this layer forming method, by including representative feature points of the previously formed weld beads, it is possible to relatively easily detect each point, which becomes information that is easy to use for control.

[0202] (4) In the layer forming method described in item (2) or (3), the geometric feature points are extracted from the previously formed weld beads disposed near the aiming position of the torch.

[0203] According to this layer forming method, by extracting geometric feature points from the previously formed weld beads near the weld bead formation position, it is possible to more accurately control the shape of the formed weld beads.

[0204] (5) In the layer forming method described in any one of items (1) to (4), in the process of changing the welding conditions,

[0205] At least one of the position, posture, welding speed, welding voltage, welding current, and feed speed of the filler material of the torch, or any combination of two or more thereof, is changed.

[0206] According to this layer forming method, it is possible to appropriately control the weld beads through various welding conditions.

[0207] (6) In the layer forming method described in any one of items (1) to (5), the shape profile is a profile obtained by performing a projection transformation on a plane including the axis of the torch, and the plane is inclined by a predetermined angle from a plane parallel to the detection direction of the weld bead based on the non-contact shape sensor.

[0208] According to this layer forming method, by aligning the sensor coordinate system of the non-contact shape sensor with the axis direction of the robot coordinate system when the weld bead is formed, a correct profile can be obtained.

[0209] (7) In the layer forming method described in any one of items (1) to (6), the difference between the cross-sectional area of the target shape of the weld bead specified in the layer forming track plan at the orthogonal cross-section in the length direction of the weld bead and the cross-sectional area of the weld bead obtained from the shape profile is used as the deviation amount.

[0210] According to this layer forming method, even when there is a large shape difference from the local target shape in the shape profile, it will not be greatly affected by this local shape difference, and the deviation amount can be reduced.

[0211] (8)In the layer forming method according to any one of (1) to (6) above, obtain a cross-sectional shape approximation curve that approximates the shape profile at the orthogonal cross-section in the length direction of the deposited bead to a curve model by regression calculation.

[0212] Use the difference between the cross-sectional area surrounded by the cross-sectional shape approximation curve and the cross-sectional area of the target shape of the deposited bead specified in the layer track plan as the deviation amount.

[0213] According to this layer forming method, by approximating the shape profile to a curve model, a cross-sectional shape approximation curve with reduced deviation in the shape measurement of the deposited bead is obtained. In addition, even with a small number of measurement points, a cross-sectional shape approximation curve with improved accuracy can be obtained. Based on the difference in cross-sectional area between this cross-sectional shape approximation curve and the target shape, the layer track plan and welding conditions are changed, so that a more accurate deposited bead can be formed.

[0214] (9)In the layer forming method according to any one of (1) to (6) above, set the cross-sectional shape approximation curve that approximates the shape profile at the orthogonal cross-section in the length direction of the deposited bead to a curve model by regression calculation such that the cross-sectional area of the region surrounded by this cross-sectional shape approximation curve is equal to the cross-sectional area of the target shape of the deposited bead specified in the layer track plan.

[0215] Use the difference between the position of the topmost part of the cross-sectional shape approximation curve and the target formation position of the deposited bead as the deviation amount.

[0216] According to this layer forming method, by obtaining the cross-sectional shape approximation curve with the constraint that the cross-sectional area difference becomes smaller, the difference between the position of the topmost part of the obtained cross-sectional shape approximation curve and the target formation position of the deposited bead is controlled to become smaller, so that a more accurate deposited bead can be formed.

[0217] (10)In the layer forming method according to any one of (1) to (6) above, use the difference between the bead height of the target shape of the deposited bead specified in the layer track plan at the orthogonal cross-section in the length direction of the deposited bead and the bead height of the deposited bead obtained from the shape profile as the deviation amount.

[0218] According to this layer forming method, by controlling to make the difference between the bead height of the measured deposited bead and the bead height of the target shape smaller, the arithmetic processing does not become complicated, and the deposited bead can be made closer to the target shape relatively simply.

[0219] (11) In the layer forming method according to any one of (1) to (6) above, obtain a cross-sectional shape approximation curve that approximates the shape profile at the orthogonal cross-section in the length direction of the deposited bead to a curve model by regression calculation.

[0220] Take the difference between the height of an arbitrary point on the cross-sectional shape approximation curve and the height of the position corresponding to this arbitrary point in the target shape of the deposited bead specified in the layer forming track plan as the deviation amount.

[0221] According to this layer forming method, by approximating the shape profile to a curve model, a cross-sectional shape approximation curve with reduced deviation in the shape measurement of the deposited bead can be obtained. In addition, even with fewer measurement points, a cross-sectional shape approximation curve with improved accuracy can be obtained. Based on the difference between the height of an arbitrary point on this cross-sectional shape approximation curve and the height of the outer contour line of the target shape, change the layer forming track plan and welding conditions, and it is possible to form a more accurate deposited bead.

[0222] (12) In the layer forming method according to any one of (1) to (6) above, set the cross-sectional shape approximation curve that approximates the shape profile at the orthogonal cross-section in the length direction of the deposited bead to a curve model by regression calculation as follows: the difference between the height of an arbitrary point on this cross-sectional shape approximation curve and the height of the position corresponding to this arbitrary point in the target shape of the deposited bead specified in the layer forming track plan becomes smaller.

[0223] Take the difference between the position of the topmost part of the cross-sectional shape approximation curve and the target formation position of the deposited bead as the deviation amount.

[0224] According to this layer forming method, obtain the cross-sectional shape approximation curve with the constraint that the bead height becomes smaller, and it is controlled so that the difference between the position of the topmost part of the obtained cross-sectional shape approximation curve and the target formation position of the deposited bead becomes smaller. Therefore, it is possible to form a more accurate deposited bead.

[0225] In addition, this application is based on a Japanese patent application (Japanese Patent Application No. 2020-88114) filed on May 20, 2020, and its content is incorporated herein by reference.

[0226] Explanation of symbols

[0227] 11 Forming device

[0228] 13 Controller

[0229] 15 Power supply device

[0230] 17 Torch

[0231] 19 Welding robot

[0232] 21 Filling material supply section

[0233] 23 Laser shape sensor (non-contact shape sensor)

[0234] 23A Laser irradiation section

[0235] 23B Detection sensor

[0236] 25 Substrate section

[0237] 31 CAD / CAM section

[0238] 33 Trajectory calculation section

[0239] 35 Storage section

[0240] 37 Control section

[0241] 100 Layered manufacturing apparatus.

Claims

1. A layered manufacturing method, in which a welding bead that melts and solidifies a filler material is layered while moving a welding torch mounted on the front end axis of a robot, the layered manufacturing method comprising: In the process of forming the deposition bead according to a layered track plan that defines the aiming position of the welding torch and the shape of the deposition bead to manufacture a layered object, a step of measuring the shape profile of the established deposition bead by a non-contact shape sensor integrally provided with the welding torch on the front end axis of the robot; A step of extracting first geometric information of the bead shape from the shape profile and the aiming position of the welding torch; A step of extracting second geometric information corresponding to the first geometric information from the layered track plan and calculating the deviation amount between the first geometric information and the second geometric information; According to the deviation amount, changing at least one of the bead height and the bead width at a cross section orthogonal to the bead length direction of the deposition bead defined in the layered track plan, thereby updating the layered track plan; and A step of changing the welding conditions according to the update result of the layered track plan, The first geometric information and the second geometric information include at least any one of the following information: geometric feature points near the aiming position of the welding torch, the bead height, the bead width, the bead cross-sectional area of the deposition bead, and a cross-sectional shape approximate curve representing the outer shape of the bead; The geometric feature points include any of the following: The vertex of the convex shape of the established deposition bead; The end point of a narrow portion formed by the outer surface of the bead being recessed inward between other deposition beads adjacent to the deposition bead; The point where the width direction end of the deposition bead intersects the lower layer on which the deposition bead is formed.

2. The layered manufacturing method according to claim 1, wherein The geometric feature points are extracted from the established deposition bead disposed near the aiming position of the welding torch.

3. The layered manufacturing method according to claim 1 or 2, wherein In the step of changing the welding conditions, At least one of the position, posture, welding speed, welding voltage, welding current, and feed speed of the filler material of the welding torch is changed.

4. The layered manufacturing method according to claim 1 or 2, wherein In the step of changing the welding conditions, Any two or more of the position, posture, welding speed, welding voltage, welding current, and feed speed of the filler material of the welding torch are combined and changed.

5. The layered manufacturing method according to claim 1 or 2, wherein The shape profile is a profile obtained by performing a projection transformation on a plane including the axis of the welding torch, and the plane is inclined by a predetermined angle from a plane parallel to the detection direction of the deposition bead based on the non-contact shape sensor.

6. The layered manufacturing method according to claim 1 or 2, wherein The difference between the cross-sectional area of the target shape of the deposited bead as specified in the layer stacking track plan at the orthogonal cross-section in the length direction of the deposited bead and the cross-sectional area of the deposited bead obtained from the shape profile is used as the deviation amount.

7. The layer stacking forming method according to claim 1 or 2, wherein, A cross-sectional shape approximation curve that approximates the shape profile at the orthogonal cross-section in the length direction of the deposited bead to a curve model is obtained by regression calculation, The difference between the cross-sectional area enclosed by the cross-sectional shape approximation curve and the cross-sectional area of the target shape of the deposited bead as specified in the layer stacking track plan is used as the deviation amount.

8. The layer stacking forming method according to claim 1 or 2, wherein, The cross-sectional shape approximation curve that approximates the shape profile at the orthogonal cross-section in the length direction of the deposited bead to a curve model obtained by regression calculation is set such that the cross-sectional area of the region enclosed by the cross-sectional shape approximation curve is equal to the cross-sectional area of the target shape of the deposited bead as specified in the layer stacking track plan, The difference between the position of the topmost part of the cross-sectional shape approximation curve and the target formation position of the deposited bead is used as the deviation amount.

9. The layer stacking forming method according to claim 1 or 2, wherein, A cross-sectional shape approximation curve that approximates the shape profile at the orthogonal cross-section in the length direction of the deposited bead to a curve model is obtained by regression calculation, The difference between the height of an arbitrary point on the cross-sectional shape approximation curve and the height of the position corresponding to the arbitrary point in the target shape of the deposited bead as specified in the layer stacking track plan is used as the deviation amount.

10. The layer stacking forming method according to claim 1 or 2, wherein, The cross-sectional shape approximation curve that approximates the shape profile at the orthogonal cross-section in the length direction of the deposited bead to a curve model obtained by regression calculation is set such that the difference between the height of an arbitrary point on the cross-sectional shape approximation curve and the height of the position corresponding to the arbitrary point in the target shape of the deposited bead as specified in the layer stacking track plan becomes smaller, The difference between the position of the topmost part of the cross-sectional shape approximation curve and the target formation position of the deposited bead is used as the deviation amount.

Images