JP2020189324A - Structure manufacturing system and manufacturing method - Google Patents

Abstract

To provide a structure manufacturing system capable of efficiently extracting internal defect candidates of a bead and manufacturing a structure of high quality, and a manufacturing method.SOLUTION: A structure molding system 10 includes: a bead formation robot 20 forming a bead 25 on a base material 23; a gas supply robot 30 supplying cooling gas for a surface of the bead 25; a track design part 62 for creating movement tracks of a welding torch 21 and a cooling gas nozzle 31; a control part 65 controlling the bead formation robot 20 and the gas supply robot 30; a temperature measurement part 40 for outputting a surface temperature distribution of the bead 25; and a defect evaluation part 64 for extracting a region surrounded by a part whose temperature gradient is larger than a threshold from the surface temperature distribution of the bead 25 as an internal defect candidate.SELECTED DRAWING: Figure 1

Description

The present invention relates to a structure manufacturing system and a manufacturing method, and more particularly to a structure manufacturing system and a manufacturing method formed by laminating beads formed by melting and solidifying a filler metal.

In recent years, there has been an increasing need for modeling using a 3D printer as a means of production, and research and development are being promoted toward the practical application of modeling using metal materials. A 3D printer for modeling a metal material uses a laser, an electron beam, or a heat source such as an arc to melt a metal powder or a metal wire, and laminates the molten metal to produce a modeled object. In particular, the laminated modeling method using an arc has a larger amount of heat input and higher modeling efficiency (amount of buildup per unit time) than a laser.

As a technique for forming such a shaped object, a welding technique is known in which a welding metal is laminated by moving a welding torch that supplies a filler material to form a shaped object such as a mold (for example,). See Patent Document 1).

Further, there is known a welded portion inspection method in which temperature distribution data of a welded portion and the vicinity of the welded portion is measured by a temperature sensor and compared with known data stored in advance to determine the quality of the welded portion (for example). , Patent Document 2).

Japanese Unexamined Patent Publication No. 2000-15363 Japanese Unexamined Patent Publication No. 6-34564

By the way, it is desired to detect welding defects such as blow holes and cracks even in a modeled object formed by additive manufacturing method using an arc. In particular, since internal defects cannot be visually confirmed from the outside, it is desired to detect them non-destructively.
The method for inspecting a welded portion of a steel sheet described in Patent Document 2 does not consider the layered manufacturing method, and it is necessary to prepare data in the case of a good welded portion in advance, and the layered model having various shapes. It would be very complicated to carry out each time.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a structure manufacturing system and manufacturing method capable of efficiently extracting internal defect candidates of beads and manufacturing a high-quality structure. To provide.

Therefore, the above object of the present invention is achieved by the following (1) structure manufacturing system and the following (2) structure manufacturing method.
(1) A bead forming robot that forms a bead formed by melting and solidifying a filler metal on a base metal using a welding torch.
A gas supply robot having a gas supply unit for supplying a cooling gas for cooling the bead to the surface of the bead formed on the base material by the bead forming robot.
A track design section for creating a moving track of the welding torch and a moving track of the gas supply section for manufacturing a structure in which the beads are laminated on the base material.
A control unit that controls the bead forming robot and the gas supply robot based on the moving trajectory created by the trajectory design unit.
A temperature measuring unit that measures the surface temperature of the bead to which the cooling gas is supplied during the manufacture of the structure and outputs the surface temperature distribution of the bead.
A defect evaluation unit that extracts a region surrounded by a portion whose temperature gradient is larger than a predetermined threshold value as an internal defect candidate from the surface temperature distribution of the bead.
Structure manufacturing system.
(2) A method for manufacturing a structure, which comprises the structure manufacturing system according to (1) and manufactures a structure in which beads are laminated on a base material.
A step of forming a bead formed by melting and solidifying a filler metal on the base metal using the welding torch of the bead forming robot based on the moving track created by the track design unit.
Based on the moving track created by the track design section, the gas supply section of the bead forming robot supplies a cooling gas for cooling the bead to the surface of the bead formed on the base material. ,
A step of measuring the surface temperature of the bead to which the cooling gas is supplied by the temperature measuring unit and outputting the surface temperature distribution of the bead during the manufacture of the structure.
A step of extracting a region surrounded by a portion whose temperature gradient is larger than a predetermined threshold value from the surface temperature distribution of the bead as an internal defect candidate by the defect evaluation unit.
A method of manufacturing a structure comprising.

According to the structure manufacturing system and manufacturing method of the present invention, internal defect candidates of beads can be efficiently extracted to manufacture a high-quality structure.

It is a conceptual diagram of the manufacturing system of the structure which concerns on this invention.

Hereinafter, the manufacturing system and manufacturing method of the structure according to the embodiment of the present invention will be described in detail with reference to the drawings.
As shown in FIG. 1, the structure manufacturing system 10 includes a bead forming robot 20, a gas supply robot 30, a temperature measuring unit 40, a shape measuring unit 50, and a controller 60.

The bead forming robot 20 is an articulated robot, and the filler metal M is continuously supplied to the welding torch 21 provided on the tip shaft. The position and posture of the welding torch 21 can be arbitrarily set three-dimensionally within the range of the degree of freedom of the robot arm.

The welding torch 21 generates an arc from the tip of the filler metal M while holding the filler metal M. The filler metal M is fed from the filler metal supply unit 22 to the welding torch 21 by a feeding mechanism (not shown) attached to a robot arm or the like. Further, the welding torch 21 is provided with a shield gas nozzle, and the shield gas supplied from a gas supply device (not shown) is ejected from the shield gas nozzle. Then, based on the moving trajectory of the welding torch 21 created by the trajectory design unit 62 described later, the filler metal M continuously fed is melted and solidified while moving the welding torch 21, and is placed on the base metal 23. The linear bead 25, which is a molten solidified body of the filler metal M, is laminated to form the structure W.
The arc welding method may be either a consumable electrode type such as shielded metal arc welding or carbon dioxide arc welding, or a non-consumable electrode type such as TIG welding or plasma arc welding, depending on the structure W to be manufactured. Selected as appropriate.

The gas supply robot 30 is an articulated robot, and a cooling gas nozzle 31 which is a gas supply unit is attached to the tip shaft. The cooling gas nozzle 31 moves based on the moving trajectory of the cooling gas nozzle 31 created by the trajectory design unit 62, which will be described later, and blows cooling gas onto the surface of the bead 25 formed by the bead forming robot 20 to cool the bead 25. .. The cooling gas is not particularly limited, and air, carbon dioxide gas, Ar gas and the like can be used. Further, as the cooling gas, the same gas as the shield gas may be used.

During the production of the structure W, the temperature measuring unit 40 continuously measures the surface temperature of the bead 25 with respect to the bead 25 to which the cooling gas is supplied, and outputs the surface temperature distribution of the bead 25. The temperature measuring unit 40 is not particularly limited as long as it can measure the surface temperature of the molded bead 25, and can be used with a contact type measuring sensor. However, since the bead 25 has a high temperature, infrared thermography or infrared rays can be used. A non-contact measurement sensor such as a camera is desirable. Infrared thermography and infrared cameras are preferable because they can detect the temperature in a wide range at once.

The shape measuring unit 50 measures the surface shape of the bead 25, and a generally used optical traveling time method (TOF method) or optical cutting method can be used.

The controller 60 includes a CAD / CAM unit 61, a trajectory design unit 62, a data storage unit 63, a defect evaluation unit 64, and a control unit 65.

After creating the shape data of the structure W to be manufactured, the CAD / CAM unit 61 divides the structure W into a plurality of layers to generate layer shape data representing the shape of each layer. The track design unit 62 generates each moving track of the welding torch 21 and the cooling gas nozzle 31 based on the generated layer shape data.

The data storage unit 63 stores the layer shape data generated by the CAD / CAM unit 61 and the moving trajectories of the welding torch 21 and the cooling gas nozzle 31 created by the track design unit 62. Further, the data storage unit 63 stores the moving trajectories of the welding torch 21 and the cooling gas nozzle 31 as log information in association with the internal defect candidates detected by the defect evaluation unit 64, which will be described later.

The defect evaluation unit 64 estimates from the surface temperature distribution of the bead 25 output from the temperature measurement unit 40 that there is a defect in the region surrounded by a portion where the temperature gradient is larger than a predetermined threshold value, and extracts it as an internal defect candidate. ..

The control unit 65 executes a drive program based on the layer shape data stored in the data storage unit 63 and the moving trajectories of the welding torch 21 and the cooling gas nozzle 31 to drive the bead forming robot 20 and the gas supply robot 30. Specifically, the bead forming robot 20 moves the welding torch 21 based on the moving trajectory of the welding torch 21 created by the trajectory design unit 62 in response to a command from the controller 60, and the bead 25 is placed on the base metal 23. Laminate. At the same time, the gas supply robot 30 moves the cooling gas nozzle 31 based on the moving trajectory of the cooling gas nozzle 31 created by the trajectory design unit 62 in response to a command from the controller 60 to cool the bead 25 immediately after generation.

Next, the operation of this embodiment will be described. In the structure manufacturing system 10, first, the track design section 62 generates the moving tracks of the welding torch 21 and the cooling gas nozzle 31 based on the layer shape data of the structure W created by the CAD / CAM section 61. Then, the control unit 65 moves the welding torch 21 based on the moving trajectory to melt and solidify the filler metal M, and the linear bead 25 which is a molten solidified body of the filler metal M is placed on the base metal 23. Are laminated to form.

At the same time, the control unit 65 moves the cooling gas nozzle 31 based on the moving trajectory of the cooling gas nozzle 31 generated by the track design unit 62, and blows cooling gas onto the surface of the bead 25 in a high temperature state to cool the bead 25.

In this way, the bead forming robot 20 and the gas supply robot 30 cooperate with each other to form the bead 25 and cool the bead 25 by two robots, so that one robot can perform the welding torch. Compared with the case where the 21 and the cooling gas nozzle 31 are replaced and the same operation is performed, the productivity is significantly improved. Further, by cooling the bead 25, the stacking start time (inter-pass time) of the bead 25 of the next layer can be shortened, which also improves the molding efficiency.

Next, the temperature measuring unit 40 continuously measures the surface temperature of the bead 25 with respect to the bead 25 after being cooled by the cooling gas, and outputs the surface temperature distribution of the bead 25. The surface temperature of the bead 25 differs in the cooling rate because the thermal conductivity is different between the defective region and the non-defect region, and the temperature gradient becomes large at the boundary between the defective region and the non-defect region.

The defect evaluation unit 64 extracts a region surrounded by a portion whose temperature gradient is larger than a predetermined threshold value from the surface temperature distribution of the bead 25 as an internal defect candidate. For example, a region having internal defects such as blow holes and slag entrainment inside the bead 25 is rapidly cooled by the cooling gas, whereas in a region without internal defects, the mass of the bead 25 holding the amount of heat is increased. Since it is large and difficult to cool, there is a temperature difference in the surface temperature of the bead 25. The defect evaluation unit 64 extracts internal defect candidates based on this temperature difference.

The internal defect candidates extracted from the surface temperature distribution of the bead 25 are stored in the data storage unit 63 as log information in association with the moving trajectories of the welding torch 21 and the cooling gas nozzle 31 created by the track design unit 62. This log information will be used for reviewing future orbit plans.
Further, the control unit 65 may perform processing such as gouging on the portion of the internal defect candidate.

As described above, the internal defect candidates extracted from the surface temperature distribution of the bead 25 may be external defects such as surface cracks and cracks. Therefore, the shape measuring unit 50 measures the surface shape of the bead 25 by a method such as an optical traveling time method (TOF method) or an optical cutting method, and extracts a concave region or a convex region on the surface of the bead 25.

Next, the defect evaluation unit 64 collates the extracted concave or convex region with the position of the internal defect candidate, and if both positions overlap, the internal defect candidate is corrected to the external defect candidate. As a result, the internal defect candidate and the external defect candidate can be clearly discriminated, and the detection accuracy of the internal defect candidate is improved. The extracted external defect candidates can be corrected in the post-welding process. Further, the internal defect candidates can be used for defect prevention measures such as changing the welding conditions.

The present invention is not limited to the above-described embodiment, and can be appropriately modified, improved, and the like.

For example, the cooling gas nozzle 31 may spray the penetrant inspection agent together with the cooling gas. The penetrant inspection agent is a red or fluorescent test solution with good permeability, and is applied to the surface of the bead 25 to create a magnified image by utilizing the capillary phenomenon and the perceptual phenomenon to remove external defects on the surface of the bead 25. It can be detected visually. Further, this external defect may be detected by collating with the internal defect candidate.

As described above, the following matters are disclosed in this specification.
(1) A bead forming robot that forms a bead formed by melting and solidifying a filler metal on a base metal using a welding torch.
A gas supply robot having a gas supply unit for supplying a cooling gas for cooling the bead to the surface of the bead formed on the base material by the bead forming robot.
A track design section for creating a moving track of the welding torch and a moving track of the gas supply section for manufacturing a structure in which the beads are laminated on the base material.
A control unit that controls the bead forming robot and the gas supply robot based on the moving trajectory created by the trajectory design unit.
A temperature measuring unit that measures the surface temperature of the bead to which the cooling gas is supplied during the manufacture of the structure and outputs the surface temperature distribution of the bead.
A defect evaluation unit that extracts a region surrounded by a portion whose temperature gradient is larger than a predetermined threshold value as an internal defect candidate from the surface temperature distribution of the bead.
Structure manufacturing system.
According to this configuration, it is possible to efficiently manufacture a high-quality structure having no internal defects in the bead.

(2) A data storage unit that associates the moving trajectory created by the trajectory design unit with the internal defect candidate and stores it as log information.
The structure manufacturing system according to (1).
According to this configuration, the log information can be used for reviewing the orbit plan in the future.

(3) The gas supply unit sprays the penetrant inspection agent together with the cooling gas.
The structure manufacturing system according to (1) or (2).
According to this configuration, external defects formed on the surface side of the bead can be easily detected visually.

(4) A shape measuring unit that measures the surface shape of the bead to which the cooling gas is supplied during the manufacture of the structure.
The structure manufacturing system according to any one of (1) to (3).
According to this configuration, a concave region or a convex region on the surface of the bead can be extracted.

(5) A concave or convex region on the surface of the bead is extracted from the surface shape measurement result obtained by the shape measuring unit, and the concave or convex region and the position of the internal defect candidate are determined. Collate and
When the concave region or the convex region and the position of the internal defect candidate overlap, the internal defect candidate is corrected to the external defect candidate.
The structure manufacturing system according to (4).
According to this configuration, the internal defect candidate and the external defect candidate can be discriminated, and the detection accuracy of the internal defect candidate is improved.

(6) A method for manufacturing a structure, comprising the structure manufacturing system according to any one of (1) to (5), and manufacturing a structure in which beads are laminated on a base material.
A step of forming a bead formed by melting and solidifying a filler metal on the base metal using the welding torch of the bead forming robot based on the moving track created by the track design unit.
Based on the moving track created by the track design section, the gas supply section of the bead forming robot supplies a cooling gas for cooling the bead to the surface of the bead formed on the base material. ,
A step of measuring the surface temperature of the bead to which the cooling gas is supplied by the temperature measuring unit and outputting the surface temperature distribution of the bead during the manufacture of the structure.
A step of extracting a region surrounded by a portion whose temperature gradient is larger than a predetermined threshold value from the surface temperature distribution of the bead as an internal defect candidate by the defect evaluation unit.
A method of manufacturing a structure comprising.
According to this configuration, it is possible to efficiently manufacture a high-quality structure having no internal defects in the bead.

10 Structure manufacturing system 20 Bead forming robot 21 Welding torch 23 Base material 25 Bead 30 Gas supply robot 31 Cooling gas nozzle (gas supply unit)
40 Temperature measurement unit 50 Shape measurement unit 62 Track design unit 63 Data storage unit 64 Defect evaluation unit 65 Control unit M filler metal W structure

Claims (6)

A bead forming robot that forms a bead formed by melting and solidifying a filler metal on a base metal using a welding torch.
A gas supply robot having a gas supply unit for supplying a cooling gas for cooling the bead to the surface of the bead formed on the base material by the bead forming robot.
A track design section for creating a moving track of the welding torch and a moving track of the gas supply section for manufacturing a structure in which the beads are laminated on the base material.
A control unit that controls the bead forming robot and the gas supply robot based on the moving trajectory created by the trajectory design unit.
A temperature measuring unit that measures the surface temperature of the bead to which the cooling gas is supplied during the manufacture of the structure and outputs the surface temperature distribution of the bead.
A defect evaluation unit that extracts a region surrounded by a portion whose temperature gradient is larger than a predetermined threshold value as an internal defect candidate from the surface temperature distribution of the bead.
Structure manufacturing system. A data storage unit that associates the moving trajectory created by the trajectory design unit with the internal defect candidate and saves it as log information.
The structure manufacturing system according to claim 1. The gas supply unit sprays the penetrant inspection agent together with the cooling gas.
The structure manufacturing system according to claim 1 or 2. A shape measuring unit that measures the surface shape of the bead to which the cooling gas is supplied during the manufacture of the structure.
The structure manufacturing system according to any one of claims 1 to 3. A concave region or a convex region on the surface of the bead is extracted from the surface shape measurement result obtained by the shape measuring unit, and the concave region or the convex region is collated with the position of the internal defect candidate.
When the concave region or the convex region and the position of the internal defect candidate overlap, the internal defect candidate is corrected to the external defect candidate.
The structure manufacturing system according to claim 4. A method for manufacturing a structure, comprising the structure manufacturing system according to any one of claims 1 to 5, and manufacturing a structure in which beads are laminated on a base material.
A step of forming a bead formed by melting and solidifying a filler metal on the base metal using the welding torch of the bead forming robot based on the moving track created by the track design unit.
Based on the moving track created by the track design section, the gas supply section of the bead forming robot supplies a cooling gas for cooling the bead to the surface of the bead formed on the base material. ,
A step of measuring the surface temperature of the bead to which the cooling gas is supplied by the temperature measuring unit and outputting the surface temperature distribution of the bead during the manufacture of the structure.
A step of extracting a region surrounded by a portion whose temperature gradient is larger than a predetermined threshold value from the surface temperature distribution of the bead as an internal defect candidate by the defect evaluation unit.
A method of manufacturing a structure comprising.

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