JP7183138B2 - MODEL PRODUCT MANUFACTURING METHOD, MODEL PRODUCT MANUFACTURING DEVICE AND PROGRAM - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a shaped article, an apparatus for manufacturing a shaped article, and a program for manufacturing a shaped article including a laminate in which a plurality of weld beads formed by melting and solidifying a filler material using an arc are stacked.

An arc profiling welding method in a consumable electrode type welding device equipped with a weaving function to oscillate the torch in the welding direction, wherein a high frequency component is superimposed on the welding current and welding voltage supplied to the consumable electrode. , from the welding current and welding voltage during welding, detect the change in the resistance value due to the height change of the electrode, and detect the deviation of the welding line from the amount of change in the detected resistance value and the lateral position of the weaving. The method is known (see, for example, US Pat.

For a predetermined time, the tip of the welding wire temporarily transitions to a non-buried state in which it does not enter the space, and the amount of deviation of the welding center position with respect to the position of the groove is calculated based on the welding current flowing between the welding wire and the base metal. An arc welding device that acquires the detection result of the amount of deviation at least in the non-buried state from the arc sensor that detects, and corrects the position of the welding torch with respect to the groove based on the detection result of the arc sensor in the non-buried state. (See Patent Document 2, for example).

Arc copying welding that detects the amount of displacement between the welding line and the actual welding position in arc copying welding, in which welding is performed along the welding line while performing the weaving operation that oscillates the torch in the welding direction. A detection method in which a waveform represented by a function that periodically repeats at the same period as the weaving period is fitted to the waveform of the welding current or welding voltage, and based on the fitted waveform, the amount of deviation in arc profiling welding is calculated. A method for detecting the amount of deviation in arc profiling welding is also known (see Patent Document 3, for example).

JP 2017-185513 A JP 2018-176255 A JP 2018-83229 A

In additive manufacturing, the number of passes is greater than that in normal welding, and it is necessary to consider the effects of deformation and contraction of the weld bead. Therefore, there is a demand for a technique for controlling the welding torch to an appropriate position by following the bead shape formed by repeatedly laminating the welding bead. However, providing a groove in additive manufacturing increases the number of man-hours, and it is almost unrealistic to provide a groove in every pass. Have difficulty.

An object of the present invention is to position a welding torch at an appropriate position without providing a bevel when manufacturing a modeled product including a laminate in which a plurality of weld beads are stacked by melting and solidifying a filler material using an arc. to control.

Based on such an object, the present invention provides a method for manufacturing a modeled product including a laminated body in which a plurality of weld beads formed by melting and solidifying a filler material using an arc is stacked, wherein the shape data of the laminated body is used. calculating the shapes of the plurality of weld beads; and setting the orbital position of the welding torch for forming the first weld bead based on the shape of the first weld bead of the plurality of weld beads. Based on the process and the shape of the second weld bead adjacent to the first weld bead among the plurality of weld beads laminated prior to the first weld bead, the welding torch is moved around a predetermined position. generating a predicted pattern that predicts a change in welding current or welding voltage when oscillating, and forming a first weld bead by running the welding torch along the track position In the forming process, a measurement pattern is acquired by measuring changes in welding current or welding voltage when the welding torch is oscillated, and the position of the welding torch is controlled so that the measurement pattern approaches the predicted pattern. provide a way.

In the generating step, the predicted pattern may be generated further based on at least one of the welding torch tilt, the welding torch rocking direction, and the welding torch rocking width.

The predetermined position may be an orbital position.

The predetermined position may be the end position of the second weld bead. In that case, in the setting step, the distance from the end position of the second weld bead is set as the track position, and in the forming step, the edge of the second weld bead when the measured pattern is closest to the predicted pattern The position of the welding torch may be controlled by identifying the end position and adding the distance to the end position.

In the forming step, the position of the welding torch may be controlled so that the measured pattern approaches the predicted pattern with respect to the predetermined feature amount. In that case, the predetermined feature amount is at least one of the rate of change over time of the welding current or welding voltage, the maximum value of the welding current or welding voltage, and the time interval at which the welding current or welding voltage reaches its maximum value. can be one.

Further, the present invention is a method for manufacturing a shaped article including a laminated body in which a plurality of weld beads formed by melting and solidifying a filler material using an arc is laminated, wherein the first weld bead is laminated before the weld bead. Welding current or welding when the welding torch is oscillated about a predetermined position generated based on the shape of the second weld bead adjacent to the first weld bead among the plurality of weld beads a step of acquiring a predicted pattern that predicts a voltage change; and a step of forming a first weld bead by running the welding torch along a track position set based on the shape of the first weld bead. In the forming step, a measurement pattern obtained by measuring changes in welding current or welding voltage when the welding torch is oscillated is acquired, and the position of the welding torch is controlled so that the measurement pattern approaches the predicted pattern. Also provided is a method for producing a

Further, the present invention provides an apparatus for manufacturing a shaped article including a laminate in which a plurality of weld beads are laminated by melting and solidifying a filler material using an arc, wherein the weld beads are laminated prior to the first weld bead. Welding current or welding when the welding torch is oscillated about a predetermined position generated based on the shape of the second weld bead adjacent to the first weld bead among the plurality of weld beads Acquisition means for acquiring a predicted pattern that predicts a change in voltage; Forming means for forming a first weld bead by running the welding torch along a track position set based on the shape of the first weld bead. and control means for controlling the position of the welding torch so that the measurement pattern obtained by measuring the change in the welding current or welding voltage when the welding torch is oscillated approaches the predicted pattern. do.

Furthermore, the present invention provides a program for causing a computer to function as an apparatus for manufacturing a modeled product including a laminate in which a plurality of weld beads formed by melting and solidifying a filler material using an arc, wherein the computer centered on a predetermined position generated based on the shape of the second weld bead adjacent to the first weld bead among the plurality of weld beads laminated prior to the first weld bead Acquisition means for acquiring a prediction pattern that predicts a change in welding current or welding voltage when the welding torch is oscillated; forming means for forming a first weld bead by oscillating the welding torch, and controlling the position of the welding torch so that a measurement pattern obtained by measuring changes in the welding current or welding voltage when the welding torch is oscillated approaches the predicted pattern. A program for functioning as control means is also provided.

According to the present invention, when manufacturing a modeled product including a laminate in which a plurality of weld beads are stacked by melting and solidifying a filler material using an arc, the welding torch is positioned at an appropriate position without providing a groove. can be controlled to

BRIEF DESCRIPTION OF THE DRAWINGS It is the figure which showed the example of a schematic structure of the metal additive manufacturing system in embodiment of this invention. It is a figure which shows the hardware structural example of the control apparatus in embodiment of this invention. FIG. 10 is a diagram showing an image of an experiment in which it was confirmed that a change in current according to the shape of a weld bead could be captured; 4 is a graph showing a cross-sectional shape of a weld bead in a work; (a) and (b) are diagrams showing the prediction of the current pattern during weaving based on the cross-sectional shape of the weld bead. (a) to (d) are graphs showing the results of the above experiment. It is the figure which showed the example of the laminate-molded article which can apply this Embodiment. 1 is a diagram showing a functional configuration example of a stacking planning device according to an embodiment of the present invention; FIG. It is the figure which showed the functional structural example of the control apparatus in embodiment of this invention. 4 is a flow chart showing an operation example of the stacking planning device according to the embodiment of the present invention; 4 is a flow chart showing an operation example of a torch position correction unit of the control device according to the embodiment of the present invention; 4 is a flow chart showing an operation example of a torch position correction unit of the control device according to the embodiment of the present invention; 4 is a flow chart showing an operation example of a torch position correction unit of the control device according to the embodiment of the present invention;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[Configuration of metal additive manufacturing system]
FIG. 1 is a diagram showing a schematic configuration example of a metal additive manufacturing system 1 according to the present embodiment.

As illustrated, the metal additive manufacturing system 1 includes a welding robot (manipulator) 10 , a CAD device 20 , a laminate planning device 30 and a control device 50 . In addition, the stacking planning device 30 writes a control program for controlling the welding robot 10 in a removable recording medium 70 such as a memory card, and the control device 50 can read out the control program written in the recording medium 70. It's like

The welding robot 10 has an arm 11 having a plurality of joints, and operates according to a control program read by the control device 50 to perform welding work. The welding robot 10 also has a welding torch 13 for forming a layered product 100, which is an example of a layered product, at the tip of the arm 11 through the wrist portion 12. As shown in FIG. In the case of the metal additive manufacturing system 1 , the welding robot 10 moves the welding torch 13 while melting the mild steel filler material (wire) 14 to manufacture the additive model 100 . Specifically, the welding torch 13 supplies the filler material 14 and generates an arc while flowing a shielding gas to melt and solidify the filler material 14 , thereby forming multiple layers of weld beads ( Hereinafter, simply referred to as “beads”) 101 are stacked to manufacture a laminate-molded article 100 . Here, an arc is used as the heat source for melting the filler metal 14, but laser or plasma may be used. The welding robot 10 also includes a feeding device for feeding the filler material 14, etc., but the description thereof will be omitted.

The CAD device 20 has a function of designing a modeled object using a computer and holding three-dimensional data obtained by the design (hereinafter referred to as “three-dimensional CAD data”). In this embodiment, three-dimensional CAD data is used as an example of the shape data of the modeled object.

The stacking planning device 30 creates a stacking plan for the laminate-molded article 100 based on the three-dimensional CAD data held by the CAD device 20 . In other words, the trajectory of the welding torch 13 is determined, and the welding conditions for welding by the welding robot 10 are determined. A control program for controlling the welding robot 10 to form the bead 101 along the determined trajectory under the determined welding conditions is then generated, and this control program is output to the recording medium 70 .

The control device 50 reads the control program from the recording medium 70 and holds it. Then, by operating this control program, according to the lamination plan created by the lamination planning device 30, that is, along the trajectory determined by the lamination planning device 30, the bead is welded under the welding conditions determined by the lamination planning device 30. Welding robot 10 is controlled to form 101 . In this embodiment, a control device 50 is provided as an example of a device for manufacturing a modeled object.

Although not shown in FIG. 1 , the metal additive manufacturing system 1 further includes a data logger 15 . The data logger 15 is electrically connected to the welding robot 10 , measures a current pattern when the welding torch 13 is weaved, and transmits the current pattern to the control device 50 .

[Hardware configuration of control device]
FIG. 2 is a diagram showing a hardware configuration example of the control device 50. As shown in FIG.

As shown in the figure, the control device 50 is realized by, for example, a general-purpose PC (Personal Computer) or the like, and includes a CPU 51 as computing means, a main memory 52 and a magnetic disk device (HDD: Hard Disk Drive) 53 as storage means. Prepare. Here, the CPU 51 executes various programs such as an OS (Operating System) and application software to realize each function of the control device 50 . The main memory 52 is a storage area for storing various programs and data used for executing them, and the HDD 53 is a storage area for storing input data to various programs and output data from various programs.

The control device 50 also provides a communication I/F 54 for communicating with the outside, a display mechanism 55 including a video memory, a display, etc., an input device 56 such as a keyboard and a mouse, and a recording medium 70 for data transmission. and a driver 57 for reading and writing. Note that FIG. 2 merely illustrates a hardware configuration when the control device 50 is realized by a computer system, and the control device 50 is not limited to the illustrated configuration.

Moreover, the hardware configuration shown in FIG. 2 can also be understood as the hardware configuration of the stacking planning device 30 . However, when describing the lamination planning device 30, the CPU 51, main memory 52, magnetic disk device 53, communication I/F 54, display mechanism 55, input device 56, and driver 57 in FIG. A disk device 33 , a communication I/F 34 , a display mechanism 35 , an input device 36 and a driver 37 are used.

[Overview of the present embodiment]
In such a metal additive manufacturing system 1, when the welding torch 13 generates an arc at a position adjacent to the formed bead 101, the change in current according to the shape of the bead 101 can be captured as follows. Confirmed by experiment.

FIG. 3 is a diagram showing an experimental image. As shown in the figure, a workpiece 200 was prepared by forming one bead 101a on a flat substrate 190. As shown in FIG. Then, the target position of the welding torch 13 is set at a position shifted by a distance Le from the end position of the bead 101a, and the bead 101b is weaved (oscillated) with an amplitude of 2 mm (1 mm to the left and right) from the target position. formed. Although only the bead 101b in this case is shown in the figure, in practice, the right direction is the positive direction of X and the left direction is the negative direction of X with respect to the end position of the bead 101a. Weaving was performed with the position set at X = -2 mm, -1 mm, 0 mm, +1 mm. Then, the tendency of the current during weaving was measured by the data logger 15 (current measurement interval was 5 msec).

FIG. 4 is a graph showing the cross-sectional shape of the bead 101a in the workpiece 200. As shown in FIG. This graph was created based on the stacking plan created by the stacking planning device 30 .

5(a) and 5(b) are diagrams showing the prediction of the current pattern during weaving based on the cross-sectional shape of the bead 101a shown in FIG. Here, as shown in FIG. 5A, it is assumed that the bead 101b is formed by weaving the welding torch 13 around the end position of the bead 101a, that is, the position of X=0 mm. Also, the position of X=0 mm is indicated by circle A, the position of X=+1 mm is indicated by circle B, and the position of X=-1 mm is indicated by circle C. FIG. Then, the predicted change pattern of the welding current is as shown in FIG. 5(b). This is based on the assumption that the distance between welding torch 13 and substrate 190 or bead 101a correlates with welding current. Therefore, the welding current is small during the time when the welding torch 13 is at the position indicated by the encircled B, and the welding current is increased during the time when the welding torch 13 is at the position indicated by the encircled C.

FIGS. 6(a)-(d) are graphs showing the results of the above experiments. In the graph, the measured current values are moving averaged at 10-point intervals (50 msec intervals) in order to facilitate consideration of trends. From FIGS. 6A to 6D, it can be seen that the peak of the current value appears most clearly when X=0 mm. Conversely, it can also be seen that the transition of the current value becomes nearly flat as the distance from the end position of the bead 101a increases. Accordingly, by finely adjusting the position of the welding torch 13 while measuring the pattern of current change during weaving, the distance between the position of the welding torch 13 and the end position of the bead 101a can be grasped.

FIG. 7 is a diagram showing an example of a laminate-molded article 110 to which the present embodiment can be applied. As illustrated, the laminate-molded product 110 is obtained by laminating beads 101 ₁ to 101 ₇ on a base material 90 . Also, it is assumed that the laminate-molded article 110 has an overhang shape having a surface facing downward with respect to the stacking direction, and the inclination angle thereof is θ. In such a laminate-molded article 110, when the bead _101-2 is formed after the bead 101-1 is formed, the current pattern measured when the welding torch ₁₃ is weaved is weaving the welding torch 13 around the track position _P2 . It is preferable to correct the position of the welding torch 13 so as to approximate the current pattern expected when the welding is performed. Also, when the bead 101-3 is formed after forming the bead _101-2 or when the bead ₁₀₁ is formed after that, the position of the welding torch 13 should be corrected in the same manner. By doing so, the tilt angle θ of the laminate-molded article 110 is realized.

[Functional configuration of the present embodiment]
(Functional configuration of lamination planning device)
FIG. 8 is a diagram showing a functional configuration example of the stacking planning device 30 in this embodiment. As illustrated, the stacking planning apparatus 30 in the present embodiment includes a CAD data acquiring unit 41, a CAD data dividing unit 42, a stacking planning unit 43, a control program generating unit 44, a predicted pattern generating unit 45, and an information output unit 46 .

The CAD data acquisition unit 41 acquires three-dimensional CAD data representing the three-dimensional shape of the laminate-molded article 100 from the CAD device 20 .

The CAD data division unit 42 divides (slices) the three-dimensional CAD data acquired by the CAD data acquisition unit 41 into a plurality of layers, thereby generating a plurality of layer shape data representing the shape of each layer. At that time, the CAD data division unit 42 may convert the three-dimensional CAD data into an internal format that facilitates division into a plurality of layers.

The lamination planning unit 43 prepares a lamination plan including welding conditions for welding the beads 101 that match the height and width of each layer of the plurality of layer shape data generated by the CAD data dividing unit 42 and the orbital position of the welding torch 13. Generate. In order to generate such a lamination plan, a model that approximates the cross-sectional shape of the bead 101 as well as the height and width of the bead 101 is required. These values may be values obtained by actual measurement experiments, or values estimated by calculation from the cross-sectional area of the amount of deposited metal. In this embodiment, while changing the amount of welding by changing the welding speed and wire feeding speed under several conditions, bead-on-plate welding and vertical lamination of several layers are performed, and the height and width of each layer under each condition Create a database of the measurement results. Then, the welding speed and the amount of welding that satisfy the desired height and width of lamination are selected when laminating, and the estimated shape of the bead 101 of each layer is calculated from the measurement results as needed, and the orbital position of the welding torch 13 is determined. In addition, the calculation method of the welding cross section may be changed according to the material of the filler material 14 and the state of the shape of the already laminated portion. Using this calculation method, we will plan the layering that includes the modeled object. In this embodiment, a bead 101 to be formed (bead 101b in FIG. 3 or FIG. 5(a)) is used as an example of the first weld bead.

The control program generator 44 generates a control program for controlling the welding robot 10 to perform welding according to the stacking plan generated by the stacking planning unit 43 .

The prediction pattern generation unit 45 refers to the lamination plan generated by the lamination plan unit 43, and based on the shape of the adjacent bead 101a in the lamination plan, predicts when the welding torch 13 is weaved around the track position in the lamination plan. A current pattern (hereinafter referred to as "predicted pattern") is generated. In the present embodiment, adjacent bead 101a is used as an example of the second weld bead. The predicted pattern generator 45 may also generate the predicted pattern further based on at least one of the inclination of the welding torch 13 , the weaving direction of the welding torch 13 , and the weaving width of the welding torch 13 . For example, when the predicted pattern is generated further based on the inclination of the welding torch 13, the distance between the bead 101a or the base material 90 used for generating the predicted pattern and the welding torch 13 can be determined by taking into consideration the inclination of the welding torch 13. good. When the predicted pattern is generated further based on the weaving direction or weaving width of the welding torch 13, the bead 101a shape portion used for generating the predicted pattern may be determined in consideration of the weaving direction or weaving width.

The information output unit 46 outputs information including the control program generated by the control program generation unit 44 and the prediction pattern generated by the prediction pattern generation unit 45 to the recording medium 70 .

(Functional configuration of control device)
FIG. 9 is a diagram showing a functional configuration example of the control device 50 in this embodiment. As illustrated, the control device 50 in the present embodiment includes an information acquisition unit 61, a control program storage unit 62, a control program execution unit 63, a predicted pattern storage unit 64, a measurement pattern reception unit 65, a torch and a position correction unit 66 .

The information acquisition unit 61 acquires information recorded on the recording medium 70 . This information includes control programs and predictive patterns. In the present embodiment, an information acquisition unit 61 is provided as an example of acquisition means for acquiring the prediction pattern.

The control program storage unit 62 stores control programs among the information acquired by the information acquisition unit 61 .

The control program execution unit 63 reads and executes the control program stored in the control program storage unit 62 . Thereby, the control program executing section 63 controls the welding robot 10 to form the bead 101 according to the lamination plan generated by the lamination planning section 43 . In the present embodiment, the control program executing section 63 is provided as an example of forming means for forming the first weld bead by running the welding torch along the track position. In addition, the control program execution unit 63 calls the torch position correction unit 66, for example, immediately after starting one pass of welding or each time welding of a predetermined length is completed during execution of one pass of welding. The position of the torch 13 is corrected.

The prediction pattern storage unit 64 stores prediction patterns among the information acquired by the information acquisition unit 61 .

The measurement pattern receiver 65 controls the data logger 15 according to the instruction from the torch position corrector 66 to measure the current pattern when the welding torch 13 is weaved. Then, the measured current pattern (hereinafter referred to as “measurement pattern”) is received from the data logger 15 .

When called by the control program execution unit 63 , the torch position correction unit 66 controls the welding robot 10 to weave the welding torch 13 and controls the measurement pattern reception unit 65 to receive the measurement pattern from the data logger 15 . Get the measurement pattern. Then, the predicted pattern stored in the predicted pattern storage unit 64 and the measured pattern acquired from the measured pattern receiving unit 65 are compared. When it is determined that the measured pattern is not close to the predicted pattern, the welding robot 10 is controlled to move the welding torch 13 in a direction intersecting the trajectory and then weaving, and the measured pattern is received from the data logger 15 again. A measurement pattern is obtained by controlling the measurement pattern reception unit 65 . Then, the predicted pattern stored in the predicted pattern storage unit 64 and the measured pattern acquired from the measured pattern receiving unit 65 are compared. The torch position correction unit 66 repeats such processing to correct the position of the welding torch 13 so that the measurement pattern received by the measurement pattern reception unit 65 approaches the predicted pattern stored in the predicted pattern storage unit 64. . In this embodiment, a torch position corrector 66 is provided as an example of control means for controlling the position of the welding torch so that the measured pattern approaches the predicted pattern. Here, the comparison between the predicted pattern and the measured pattern may be performed for a predetermined feature amount of each pattern. In this case, at least one of the rate of change over time of the welding current, the maximum value of the welding current, and the time interval at which the welding current reaches the maximum value may be used as the predetermined feature amount.

[Operation of this embodiment]
(Operation of lamination planning device)
FIG. 10 is a flow chart showing an operation example of the stacking planning device 30 in this embodiment.

In the stacking planning device 30, first, the CAD data acquisition unit 41 acquires three-dimensional CAD data from the CAD device 20 (step 301).

Next, the CAD data division unit 42 divides the three-dimensional CAD data acquired in step 301 into a plurality of layers to generate layer shape data (step 302).

Next, the lamination planning section 43 generates a lamination plan from the layer shape data generated in step 302 (step 303).

Next, the control program generation unit 44 generates a control program for controlling the welding robot 10 to form the laminate-molded article 100 by forming the bead 101 according to the lamination plan generated in step 303 (step 304). .

On the other hand, the predicted pattern generation unit 45 generates a predicted pattern, which is a current pattern predicted when the welding torch 13 is weaved around the track position, from the lamination plan generated in step 303 (step 305).

Finally, the information output unit 46 outputs the control program generated in step 304 and the prediction pattern generated in step 305 to the recording medium 70 (step 306).

(Operation of control device)
In the control device 50, the information acquisition unit 61 first acquires the control program and the prediction pattern from the recording medium 70, stores the control program in the control program storage unit 62, and stores the prediction pattern in the prediction pattern storage unit 64, respectively. Then, the control program execution unit 63 reads the control program stored in the control program storage unit 62 and executes it.

At that time, the control program executed by the control program execution unit 63, for example, immediately after the start of one pass of welding, or each time welding of a predetermined length during the execution of one pass of welding, the torch position correction unit 66 is called and executed.

11-1 to 11-3 are flow charts showing an operation example of the torch position corrector 66. FIG. In this flowchart, the minimum unit of the distance by which the position of the welding torch 13 is advanced is represented by Δ. Δ may be a distance smaller than the minimum unit (1 mm in FIG. 3) of the distance from the end position of the bead 101a set for generating the predicted pattern. Also, in this flowchart, the result of comparing the predicted pattern and the measured pattern is simply referred to as "difference", but this may be the difference between the feature amount of the predicted pattern and the feature amount of the measured pattern.

As shown in FIG. 11-1, when the torch position correction unit 66 is called from the control program, first, while controlling the welding robot 10 to weave the welding torch 13, the measurement pattern receiving unit 65 is controlled to perform measurement. A pattern is received and acquired from the measurement pattern receiving section 65 (step 501).

Then, the torch position correction unit 66 compares the predicted pattern stored in the predicted pattern storage unit 64 and the measurement pattern acquired in step 501, and calculates the difference (step 502).

Next, the torch position corrector 66 advances the position of the welding torch 13 by +Δ (step 503). That is, the welding robot 10 is controlled to move the welding torch 13 in the positive direction by Δ.

In this state, the torch position correction unit 66 again controls the welding robot 10 to weave the welding torch 13, and controls the measurement pattern reception unit 65 to receive the measurement pattern. (step 504).

Then, the torch position correction unit 66 compares the predicted pattern stored in the predicted pattern storage unit 64 and the measurement pattern acquired in step 504, and calculates the difference (step 505).

Next, the torch position correction unit 66 determines whether the current difference calculated in step 505 is greater than the initial difference calculated in step 502 (step 506).

First, the case where it is not determined in step 506 that the current difference is larger than the initial difference will be described. In this case, the position of the welding torch 13 that minimizes the difference between the predicted pattern and the measured pattern may be in the positive direction. Therefore, the torch position correction unit 66 stores the difference of this time (step 507).

Next, the torch position corrector 66 advances the position of the welding torch 13 by +Δ as shown in FIG. 11-2 (step 521). That is, the welding robot 10 is controlled to move the welding torch 13 in the positive direction by Δ.

In this state, the torch position correction unit 66 again controls the welding robot 10 to weave the welding torch 13, and controls the measurement pattern reception unit 65 to receive the measurement pattern. (step 522).

Then, the torch position correction unit 66 compares the predicted pattern stored in the predicted pattern storage unit 64 and the measurement pattern acquired in step 522, and calculates the difference (step 523).

Next, the torch position corrector 66 determines whether the current difference calculated in step 523 is greater than the previous difference calculated in step 505 or step 523 (step 524).

Unless it is determined that the current difference is greater than the previous difference, there is a possibility that the position of the welding torch 13 where the difference between the predicted pattern and the measured pattern is the smallest is in the further positive direction. Therefore, the torch position correction unit 66 stores the difference this time (step 525) and returns the process to step 521. FIG.

If it is determined that the difference this time is larger than the difference of the previous time, it is difficult to think that the position of the welding torch 13 where the difference between the predicted pattern and the measured pattern is the smallest is in the further positive direction. Therefore, the torch position correction unit 66 advances the position of the welding torch 13 by -Δ (step 526). That is, the welding robot 10 is controlled to move the welding torch 13 in the negative direction by Δ. Then, assuming that the position of the welding torch 13 set in this manner is the correct position of the welding torch 13, the process is terminated.

Also, referring back to FIG. 11A, the case where it is determined in step 506 that the current difference is larger than the initial difference will be described. In this case, it is difficult to think that the position of the welding torch 13 where the difference between the predicted pattern and the measured pattern is the smallest is in the positive direction. Therefore, the torch position correction unit 66 advances the position of the welding torch 13 by -2Δ (step 508). That is, the welding robot 10 is controlled to move the welding torch 13 by 2Δ in the negative direction from the position Δ in the positive direction.

In this state, the torch position correction unit 66 again controls the welding robot 10 to weave the welding torch 13, and controls the measurement pattern reception unit 65 to receive the measurement pattern. (step 509).

Then, the torch position correction unit 66 compares the predicted pattern stored in the predicted pattern storage unit 64 and the measurement pattern acquired in step 509, and calculates the difference (step 510).

Next, the torch position corrector 66 determines whether the current difference calculated in step 510 is greater than the initial difference calculated in step 502 (step 511).

First, the case where it is not determined in step 511 that the current difference is larger than the initial difference will be described. In this case, there is a possibility that the position of the welding torch 13 that minimizes the difference between the predicted pattern and the measured pattern is in the negative direction. Therefore, the torch position correction unit 66 stores the difference of this time (step 512).

Next, as shown in FIG. 11-3, the torch position corrector 66 advances the position of the welding torch 13 by -Δ (step 541). That is, the welding robot 10 is controlled to move the welding torch 13 in the negative direction by Δ.

In this state, the torch position correction unit 66 again controls the welding robot 10 to weave the welding torch 13, and controls the measurement pattern reception unit 65 to receive the measurement pattern. (step 542).

Then, the torch position correction unit 66 compares the predicted pattern stored in the predicted pattern storage unit 64 and the measurement pattern acquired in step 542, and calculates the difference (step 543).

Next, the torch position correction unit 66 determines whether the current difference calculated in step 543 is greater than the previous difference calculated in step 510 or step 543 (step 544).

Unless it is determined that the current difference is greater than the previous difference, there is a possibility that the position of the welding torch 13 where the difference between the predicted pattern and the measured pattern is the smallest is further in the negative direction. Therefore, the torch position correction unit 66 stores the difference for this time (step 545) and returns the process to step 541. FIG.

If it is determined that the difference this time is larger than the difference of the previous time, it is difficult to think that the position of the welding torch 13 where the difference between the predicted pattern and the measured pattern is the smallest is in the further positive direction. Therefore, the torch position correction unit 66 advances the position of the welding torch 13 by +Δ (step 546). That is, the welding robot 10 is controlled to move the welding torch 13 in the positive direction by Δ. Then, assuming that the position of the welding torch 13 set in this manner is the correct position of the welding torch 13, the process is terminated.

Also, referring back to FIG. 11A, the case where it is determined in step 511 that the current difference is larger than the initial difference will be described. In this case, it is difficult to think that the position of the welding torch 13 where the difference between the predicted pattern and the measured pattern is the smallest is in the positive direction. Therefore, the torch position correction unit 66 advances the position of the welding torch 13 by +Δ (step 513). That is, the welding robot 10 is controlled to move the welding torch 13 in the positive direction by Δ. Then, assuming that the position of the welding torch 13 set in this manner is the correct position of the welding torch 13, the process is terminated.

In this operation example, the position of the welding torch 13 is advanced in the positive direction and the negative direction to find the position of the welding torch 13 that minimizes the difference between the predicted pattern and the measured pattern. position, but not limited to this. For example, the position of the welding torch 13 is advanced in the positive direction and the negative direction to find the position of the welding torch 13 where the difference between the predicted pattern and the measured pattern is equal to or less than a predetermined threshold value, and this position is determined to be the correct position of the welding torch 13. may be

[Modification of this Embodiment]
In the above description, the lamination planning device 30 weaves the welding torch 13 around the track position to generate the predicted pattern, but this is not the only option. The predicted pattern may be generated by weaving the welding torch 13 around the edge position of the adjacent bead 101a. Alternatively, the prediction pattern may be generated by weaving the welding torch 13 around a predetermined position other than the track position and the end position of the adjacent bead 101a. In that sense, the track position and the end position of the adjacent bead 101a are examples of predetermined positions.

When the lamination planning device 30 generates the predicted pattern at the track position, the control device 50 obtains the position of the welding torch 13 when the predicted pattern and the measured pattern are closest to each other, as described above, and determines the position of the welding torch 13 as the correct welding torch. Position 13 may be used. On the other hand, when the lamination planning device 30 generates a prediction pattern by weaving the welding torch 13 around the end position of the adjacent bead 101a, the distance from the end position of the adjacent bead 101a is set as the trajectory position. You should keep it. Then, the control device 50 obtains the position of the welding torch 13 when the predicted pattern and the measured pattern are the closest, and adds the set distance to obtain the correct position of the welding torch 13 .

In the above description, a pattern obtained by predicting a change in the welding current when the welding torch 13 is weaved is defined as a predicted pattern, and a pattern obtained by measuring a change in the welding current when the welding torch 13 is weaved is defined as a measured pattern. Not as long. A pattern obtained by predicting a change in welding voltage when the welding torch 13 is weaved may be used as a predicted pattern, and a pattern obtained by measuring a change in welding voltage when the welding torch 13 is weaved may be used as a measured pattern. In that sense, the predicted pattern can be said to be an example of a pattern that predicts changes in welding current or welding voltage when the welding torch is oscillated, and the measurement pattern is an example of a pattern that predicts changes in welding current or welding voltage when the welding torch is oscillated. It can be said that this is an example of a pattern obtained by measuring changes in welding current or welding voltage.

[Effects of this embodiment]
As described above, in the present embodiment, the measurement pattern, which is the pattern of change in the actually measured welding current or welding voltage, is predicted to be the pattern of change in welding current or welding voltage created from the lamination plan. The position of the welding torch 13 is adjusted so as to approach the pattern. As a result, when manufacturing a layered product 100 by stacking a plurality of beads 101 formed by melting and solidifying the filler material 14 using an arc, the welding torch 13 is controlled to an appropriate position without providing a groove. became possible.

DESCRIPTION OF SYMBOLS 1... Metal additive manufacturing system, 10... Welding robot, 20... CAD apparatus, 30... Lamination planning apparatus, 41... CAD data acquisition part, 42... CAD data division part, 43... Lamination planning part, 44... Control program generation part, 45... Predicted pattern generator, 46... Information output unit, 50... Control device, 61... Information acquisition unit, 62... Control program storage unit, 63... Control program execution unit, 64... Predicted pattern storage unit, 65... Measurement pattern reception Section 66 Torch position correction section 70 Recording medium

Claims (8)

A method for manufacturing a shaped article including a laminate in which a plurality of weld beads are stacked by melting and solidifying a filler material using an arc,
a step of calculating shapes of a plurality of weld beads using the shape data of the laminate;
setting an orbital position of a welding torch for forming the first weld bead based on the shape of the first weld bead among the plurality of weld beads;
swinging the welding torch around the orbital position based on the shape of a second weld bead adjacent to the first weld bead among the plurality of weld beads laminated prior to the first weld bead; generating a predicted pattern that predicts a change in welding current or welding voltage when moved;
forming the first weld bead by traveling the welding torch along the track location;
In the forming step, a measurement pattern obtained by measuring a change in welding current or welding voltage when the welding torch is oscillated is acquired, and the position of the welding torch is controlled so that the measurement pattern approaches the predicted pattern. A method for manufacturing a modeled object, characterized by: A method for manufacturing a shaped article including a laminate in which a plurality of weld beads are stacked by melting and solidifying a filler material using an arc,
a step of calculating shapes of a plurality of weld beads using the shape data of the laminate;
setting an orbital position of a welding torch for forming the first weld bead based on the shape of the first weld bead among the plurality of weld beads;
Based on the shape of the second weld bead adjacent to the first weld bead among the plurality of weld beads laminated prior to the first weld bead, the end position of the second weld bead is determined. a step of generating a prediction pattern that predicts a change in welding current or welding voltage when the welding torch is oscillated about the center;
forming the first weld bead by traveling the welding torch along the track location;
In the setting step, a distance from the end position of the second weld bead is set as the track position,
In the forming step, a measurement pattern obtained by measuring a change in welding current or welding voltage when the welding torch is oscillated is acquired, and the position of the welding torch is controlled so that the measurement pattern approaches the predicted pattern. Then, the position of the welding torch is controlled by specifying the end position of the second weld bead when the measured pattern is closest to the predicted pattern, and adding the distance to the end position. A method for manufacturing a modeled object, characterized by: In the generating step, the predicted pattern is generated further based on at least one of an inclination of the welding torch, a swing direction of the welding torch, and a swing width of the welding torch. 3. The method of manufacturing a modeled article according to claim 1 or 2 . 3. The shaped article according to claim 1, wherein in the forming step, the position of the welding torch is controlled so that the measured pattern approaches the predicted pattern with respect to a predetermined feature amount. Production method. The predetermined feature amount includes a rate of time change of the welding current or the welding voltage, a maximum value of the welding current or the welding voltage, and a time interval at which the welding current or the welding voltage takes the maximum value. 5. The method of manufacturing a modeled object according to claim 4, wherein at least one of them is selected. A method for manufacturing a shaped article including a laminate in which a plurality of weld beads are stacked by melting and solidifying a filler material using an arc,
Among the plurality of weld beads laminated before the first weld bead, the shape of the first weld bead generated based on the shape of the second weld bead adjacent to the first weld bead Acquiring a prediction pattern that predicts a change in welding current or welding voltage when the welding torch is oscillated about the orbital position set based on
forming the first weld bead by traveling the welding torch along the track location ;
In the forming step, a measurement pattern obtained by measuring a change in welding current or welding voltage when the welding torch is oscillated is obtained, and the position of the welding torch is controlled so that the measurement pattern approaches the predicted pattern. A method for manufacturing a modeled object, characterized by: An apparatus for manufacturing a shaped object including a laminate in which a plurality of weld beads are laminated by melting and solidifying a filler material using an arc,
Among the plurality of weld beads laminated before the first weld bead, the shape of the first weld bead generated based on the shape of the second weld bead adjacent to the first weld bead Acquisition means for acquiring a prediction pattern that predicts a change in welding current or welding voltage when the welding torch is oscillated about the orbital position set based on
forming means for forming the first weld bead by running the welding torch along the track position ;
and control means for controlling the position of the welding torch so that a measurement pattern obtained by measuring changes in the welding current or welding voltage when the welding torch is oscillated approaches the predicted pattern. Equipment for manufacturing things. A program for causing a computer to function as a manufacturing apparatus for a modeled product including a laminate in which a plurality of weld beads are stacked by melting and solidifying a filler material using an arc,
said computer,
Among the plurality of weld beads laminated before the first weld bead, the shape of the first weld bead generated based on the shape of the second weld bead adjacent to the first weld bead Acquisition means for acquiring a prediction pattern that predicts a change in welding current or welding voltage when the welding torch is oscillated about the orbital position set based on
forming means for forming the first weld bead by running the welding torch along the track position ;
A program for functioning as control means for controlling the position of the welding torch so that a measurement pattern obtained by measuring changes in welding current or welding voltage when the welding torch is oscillated approaches the predicted pattern.

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