JP7160759B2 - STRUCTURE MANUFACTURING SYSTEM AND MANUFACTURING METHOD - Google Patents

Description

TECHNICAL FIELD The present invention relates to a system and method for manufacturing a structure, and more particularly to a system and method for manufacturing a structure formed by laminating beads made by melting and solidifying a filler material.

In recent years, there is an increasing need for modeling using 3D printers as a means of production, and research and development are proceeding toward the practical use of modeling using metal materials. A 3D printer that models metal materials uses heat sources such as lasers, electron beams, and arcs to melt metal powder and metal wires, and laminates the molten metals to create models. In particular, the lamination molding method using an arc has a large amount of heat input and a high molding efficiency (filling amount per unit time) as compared with a laser.

As a technique for forming such a shaped object, there is known a welding technology for forming a shaped object such as a mold by moving a welding torch that supplies a filler material, thereby laminating weld metal (for example, See Patent Document 1).

There is also known a weld inspection method for determining the quality of a weld by measuring the temperature distribution data of the weld and the vicinity of the weld with a temperature sensor and comparing it with known data stored in advance (for example, , see Patent Document 2).

JP-A-2000-15363 JP-A-6-34564

By the way, it is desired to detect weld defects such as blowholes and cracks also in a modeled object modeled by the additive manufacturing method using an arc. In particular, since internal defects cannot be visually confirmed from the outside, non-destructive detection is desired.
The steel plate weld zone inspection method described in Patent Document 2 does not consider the layered manufacturing method, and it is necessary to prepare data in advance for good welds, and layered products with various shapes It would be very complicated to do it every time.

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

Accordingly, the above object of the present invention is achieved by the structure manufacturing system described in (1) below and the structure manufacturing method described in (2) below.
(1) a bead forming robot that forms a bead on the base material by melting and solidifying the filler material using a welding torch;
a gas supply robot having a gas supply unit that supplies cooling gas for cooling the bead to the surface of the bead formed on the base material by the bead forming robot;
a trajectory designing section that creates a moving trajectory of the welding torch and a moving trajectory 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 movement 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 manufacturing of the structure and outputs the surface temperature distribution of the bead;
a defect evaluation unit that extracts, as an internal defect candidate, an area surrounded by a portion having a temperature gradient greater than a predetermined threshold from the surface temperature distribution of the bead;
A structure manufacturing system comprising:
(2) A structure manufacturing method comprising the structure manufacturing system according to (1) and manufacturing a structure in which beads are laminated on a base material,
a step of forming a bead by melting and solidifying a filler material on the base material using the welding torch of the bead forming robot based on the movement trajectory created by the trajectory design unit;
a step of supplying cooling gas for cooling the bead formed on the base material to the surface of the bead formed on the base material by the gas supply unit of the bead forming robot based on the movement trajectory created by the trajectory design unit; ,
a step of measuring the surface temperature of the bead to which the cooling gas is supplied during the manufacture of the structure by the temperature measuring unit and outputting the surface temperature distribution of the bead;
a step of extracting a region surrounded by a portion having a temperature gradient larger than a predetermined threshold from the surface temperature distribution of the bead by the defect evaluation unit as an internal defect candidate;
A method of manufacturing a structure comprising

According to the structure manufacturing system and the structure manufacturing method of the present invention, a high-quality structure can be manufactured by efficiently extracting the internal defect candidate of the bead.

1 is a conceptual diagram of a structure manufacturing system according to the present invention; FIG.

Hereinafter, a structure manufacturing system and a structure manufacturing method according to embodiments 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 section 40 , a shape measuring section 50 and a controller 60 .

The bead forming robot 20 is a multi-joint robot, and is supported by a welding torch 21 provided on the tip shaft so that the filler material M can be continuously supplied. The position and posture of the welding torch 21 can be arbitrarily set three-dimensionally within the range of degrees of freedom of the robot arm.

The welding torch 21 holds the filler material M and generates an arc from the tip of the filler material M. The filler material M is fed from the filler material supply unit 22 to the welding torch 21 by a feeding mechanism (not shown) attached to a robot arm or the like. Moreover, the welding torch 21 is provided with a shield gas nozzle, and a shield gas supplied from a gas supply device (not shown) is ejected from the shield gas nozzle. Then, while moving the welding torch 21 based on the movement trajectory of the welding torch 21 created by the trajectory design unit 62 described later, the continuously fed filler material M is melted and solidified, and is deposited on the base material 23. A structural body W is formed by stacking linear beads 25 which are melted and solidified bodies of the filler material M. As shown in FIG.
The arc welding method may be a consumable electrode type such as coated arc welding or carbon dioxide gas arc welding, or a non-consumable electrode type such as TIG welding or plasma arc welding. Selected as appropriate.

The gas supply robot 30 is an articulated robot, and a cooling gas nozzle 31 as a gas supply unit is attached to the tip shaft. The cooling gas nozzle 31 cools the bead 25 by blowing the cooling gas onto the surface of the bead 25 formed by the bead forming robot 20 while moving based on the movement trajectory of the cooling gas nozzle 31 created by the trajectory designing unit 62 to be described later. . The cooling gas is not particularly limited, and air, carbon dioxide gas, Ar gas, or the like can be used. Also, the cooling gas may be the same gas as the shield gas.

The temperature measurement unit 40 continuously measures the surface temperature of the bead 25 to which the cooling gas is supplied during the manufacture of the structure W, and outputs the surface temperature distribution of the bead 25 . The temperature measurement unit 40 is not particularly limited as long as it can measure the surface temperature of the shaped bead 25, and a contact-type measurement sensor can also be used. A non-contact measurement sensor such as a camera is desirable. Infrared thermography and infrared cameras are preferable because they are capable of detecting temperature over a wide area at once.

The shape measuring unit 50 measures the surface shape of the bead 25, and can use a generally used light transit time method (TOF method) or light section method.

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

The CAD/CAM unit 61 creates shape data of the structure W to be manufactured, divides the structure W into a plurality of layers, and generates layer shape data representing the shape of each layer. The trajectory design unit 62 generates movement trajectories for the welding torch 21 and the cooling gas nozzle 31 based on the generated layer shape data.

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

From the surface temperature distribution of the bead 25 output from the temperature measurement unit 40, the defect evaluation unit 64 presumes that there is a defect in an area surrounded by portions where the temperature gradient is greater than a predetermined threshold, and extracts the defect as an internal defect candidate. .

The control unit 65 drives the bead forming robot 20 and the gas supply robot 30 by executing a drive program based on the layer shape data stored in the data storage unit 63 and the movement trajectories of the welding torch 21 and the cooling gas nozzle 31 . Specifically, the bead forming robot 20 moves the welding torch 21 based on the movement trajectory of the welding torch 21 created by the trajectory designing unit 62 in accordance with a command from the controller 60 to form the bead 25 on the base material 23. Laminate. At the same time, the gas supply robot 30 moves the cooling gas nozzle 31 based on the movement trajectory of the cooling gas nozzle 31 created by the trajectory designing unit 62 according to the 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 , the trajectory designing section 62 first generates moving trajectories for 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, melts and solidifies the filler material M, and forms a linear bead 25 which is a molten solidified body of the filler material M on the base material 23 . are laminated to form.

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

In this manner, the bead forming robot 20 and the gas supplying robot 30 work together to share the formation of the bead 25 and the cooling of the bead 25 between the two robots. 21 and the cooling gas nozzle 31 are exchanged and the same operation is performed, the productivity is significantly improved. Furthermore, by cooling the bead 25, the lamination start time (time between passes) of the bead 25 of the next layer can be shortened, which also improves the modeling efficiency.

Next, the temperature measurement unit 40 continuously measures the surface temperature of the bead 25 after being cooled by the cooling gas, and outputs the surface temperature distribution of the bead 25 . As for the surface temperature of the bead 25, since the thermal conductivity is different between the area with the defect and the area without the defect, the cooling rate differs, and the temperature gradient is large at the boundary between the area with the defect and the area without the defect.

The defect evaluation unit 64 extracts, from the surface temperature distribution of the bead 25, a region surrounded by a portion where the temperature gradient is greater than a predetermined threshold value as an internal defect candidate. For example, a region with internal defects such as blowholes 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 that retains heat is reduced to Since the bead 25 is hard to cool down, a temperature difference is generated 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 movement trajectories of the welding torch 21 and the cooling gas nozzle 31 created by the trajectory design unit 62 . This log information will be used for reviewing future trajectory 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 cracks and cracks on the surface. Therefore, the shape measuring unit 50 measures the surface shape of the bead 25 by a method such as the time-of-light method (TOF method) or the light section 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 the positions of both overlap, corrects the internal defect candidate 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 a post-welding process. In addition, internal defect candidates can be used for defect prevention measures such as changing welding conditions.

It should be noted that the present invention is not limited to the above-described embodiments, and can be modified, improved, etc. as appropriate.

For example, the cooling gas nozzle 31 may spray the penetrant testing agent together with the cooling gas. The penetrant testing agent is a red or fluorescent inspection liquid with good penetrability. It can be detected visually. Also, this external defect may be detected by matching with internal defect candidates.

As described above, this specification discloses the following matters.
(1) a bead forming robot that forms a bead on the base material by melting and solidifying the filler material using a welding torch;
a gas supply robot having a gas supply unit that supplies cooling gas for cooling the bead to the surface of the bead formed on the base material by the bead forming robot;
a trajectory designing section that creates a moving trajectory of the welding torch and a moving trajectory 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 movement 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 manufacturing of the structure and outputs the surface temperature distribution of the bead;
a defect evaluation unit that extracts, as an internal defect candidate, an area surrounded by a portion having a temperature gradient greater than a predetermined threshold from the surface temperature distribution of the bead;
A structure manufacturing system comprising:
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 movement 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), further comprising:
According to this configuration, the log information can be utilized for future review of the trajectory plan.

(3) The gas supply unit sprays a penetrant testing agent together with the cooling gas.
A manufacturing system for a structure according to (1) or (2).
According to this configuration, it is possible to easily visually detect an external defect formed on the surface side of the bead.

(4) a shape measuring unit that measures the surface shape of the bead to which the cooling gas is supplied during the manufacturing of the structure;
The structure manufacturing system according to any one of (1) to (3), further comprising:
According to this configuration, it is possible to extract a concave region or a convex region on the surface of the bead.

(5) extracting a concave region or a convex region on the surface of the bead from the surface shape measurement result obtained by the shape measuring unit, and determining the concave region or the convex region and the position of the internal defect candidate; collate,
correcting the internal defect candidate to an external defect candidate when the position of the internal defect candidate overlaps with the concave region or the convex region;
A manufacturing system for the structure according to (4).
According to this configuration, internal defect candidates and external defect candidates can be discriminated, and the detection accuracy of internal defect candidates is improved.

(6) A structure manufacturing method 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 by melting and solidifying a filler material on the base material using the welding torch of the bead forming robot based on the movement trajectory created by the trajectory design unit;
a step of supplying cooling gas for cooling the bead formed on the base material to the surface of the bead formed on the base material by the gas supply unit of the bead forming robot based on the movement trajectory created by the trajectory design unit; ,
a step of measuring the surface temperature of the bead to which the cooling gas is supplied during the manufacture of the structure by the temperature measuring unit and outputting the surface temperature distribution of the bead;
a step of extracting an area surrounded by a portion having a temperature gradient larger than a predetermined threshold from the surface temperature distribution of the bead by the defect evaluation unit as an internal defect candidate;
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 material W structure

Claims (6)

a bead forming robot that forms a bead on the base material by melting and solidifying the filler material using a welding torch;
a gas supply robot having a gas supply unit that supplies cooling gas for cooling the bead to the surface of the bead formed on the base material by the bead forming robot;
a trajectory designing section that creates a moving trajectory of the welding torch and a moving trajectory 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 movement 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 manufacturing of the structure and outputs the surface temperature distribution of the bead;
a defect evaluation unit that extracts, as an internal defect candidate, an area surrounded by a portion having a temperature gradient greater than a predetermined threshold from the surface temperature distribution of the bead;
A structure manufacturing system comprising: a data storage unit that associates the movement trajectory created by the trajectory design unit with the internal defect candidate and stores it as log information,
The structure manufacturing system of claim 1, further comprising: The gas supply unit sprays a penetrant testing agent together with the cooling gas,
3. A manufacturing system for a structure 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 manufacturing of the structure,
The structure manufacturing system according to any one of claims 1 to 3, further comprising: Extracting a concave region or a convex region on the surface of the bead from the surface shape measurement result obtained by the shape measuring unit, comparing the concave region or the convex region with the position of the internal defect candidate,
correcting the internal defect candidate to an external defect candidate when the position of the internal defect candidate overlaps with the concave region or the convex region;
5. The structure manufacturing system according to claim 4. A structure manufacturing method 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 by melting and solidifying a filler material on the base material using the welding torch of the bead forming robot based on the movement trajectory created by the trajectory design unit;
a step of supplying cooling gas for cooling the bead formed on the base material to the surface of the bead formed on the base material by the gas supply unit of the bead forming robot based on the movement trajectory created by the trajectory design unit; ,
a step of measuring the surface temperature of the bead to which the cooling gas is supplied during the manufacture of the structure by the temperature measuring unit and outputting the surface temperature distribution of the bead;
a step of extracting an area surrounded by a portion having a temperature gradient larger than a predetermined threshold from the surface temperature distribution of the bead by the defect evaluation unit as an internal defect candidate;
A method of manufacturing a structure comprising

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