JP2023019758A - Method for controlling lamination molding system, lamination molding system, and program - Google Patents

Abstract

To enable the molding of a laminated molding while optimizing a replacement frequency of a welding torch or a welding torch component in a lamination molding system.SOLUTION: A method for controlling a lamination molding system for molding a laminated molding by laminating a weld bead obtained by melting and solidifying a filler material includes an extraction step for extracting a trajectory of a lamination path from a lamination plan of the laminated molding, a calculation step for calculating coordinate information of a movement space in which the welding torch passes through and coordinate information of an exclusion space where the welding bead which has been already laminated excludes the intrusion of the welding torch on the basis of the trajectory, a determination step for determining whether spatial overlapping exists between the movement space and the exclusion space on the basis of the coordinate information of the exclusion space and the coordinate information of the movement space, and a generation step for generating a command to perform replacement work of the welding torch or a welding torch component so as to reduce the diameter of the welding torch in the case of determining that the spatial overlapping exists.SELECTED DRAWING: Figure 3

Description

The present invention relates to a control method for a laminate manufacturing system that models a laminate manufacturing object while moving a welding torch, the laminate manufacturing system, and a program.

US Pat. No. 5,300,005 discloses a system for servicing a welding torch, comprising a gripping module for holding and releasing parts of the welding torch, movable along the axis of the gripping module and about the axis of the gripping module. A system is described comprising a gripping module that is rotatable and a control system that provides freedom of movement of the gripping module to control or reduce forces between mating parts of a welding torch when parts are removed or replaced. It is

Japanese Patent Publication No. 2019-518612

In an additive manufacturing system that creates an additive manufacturing object while moving the welding torch, depending on the shape of the additive manufacturing object, the welding torch and the additive manufacturing object interfere with each other, causing an equipment error and requiring maintenance and recovery work for the equipment. becomes. It is desirable to make the diameter of the welding torch relatively small in order to reduce interference. becomes shorter, resulting in a decrease in molding efficiency.

SUMMARY OF THE INVENTION An object of the present invention is to enable a laminate-molded article to be fabricated while optimizing the replacement frequency of a welding torch or welding torch parts in a laminate-molded article.

Based on such an object, the present invention provides a control method for a laminate manufacturing system that forms a laminate-molded article by laminating welding beads obtained by melting and solidifying a filler material while moving a welding torch. An extraction step of extracting the trajectory of the stacking pass from the stacking plan of the object, based on the trajectory, the coordinate information of the moving space through which the welding torch passes, and the exclusion space where the already laminated welding bead excludes the welding torch from entering. a determination step of determining whether there is a spatial overlap between the moving space and the excluded space based on the coordinate information of the excluded space and the coordinate information of the moving space; generating a command to replace the welding torch or the welding torch part so that the diameter of the welding torch becomes smaller when it is determined that there is an excessive overlap. do.

The method of controlling the additive manufacturing system may further include a modifying step of modifying the order of the stacking passes to reduce the number of replacement operations.

A control method for an additive manufacturing system comprises a measuring step of measuring the shape of a weld bead already laminated while moving a welding torch, and a changing step of changing the coordinate information of the exclusion space based on the measured shape. It may further include.

In the control method of the additive manufacturing system, in the calculation step, a movement space is calculated by applying a model figure prepared in advance based on at least one of the inclination angle of the welding torch, the diameter of the welding torch, and the arrangement of the trajectory to the trajectory. It can be anything.

A control method for an additive manufacturing system includes, in a calculation step, applying a model figure prepared in advance based on at least one of a width of a welding bead, a height of a welding bead, an angle formed by the trajectory, and an arrangement of the trajectory to the trajectory. , computing the excluded space.

In addition, the present invention is a control method for a laminate manufacturing system that forms a laminate-molded article by laminating welding beads obtained by melting and solidifying a filler material while moving a welding torch, wherein A first control step of controlling the welding bead to be laminated, and replacement of the welding torch or welding torch parts so that the diameter of the welding torch becomes smaller when the welding torch and the laminated welding bead interfere with each other. A control method for an additive manufacturing system is also provided, including a second control step of controlling to perform

Furthermore, the present invention is a laminate manufacturing system for manufacturing a laminate-molded object by laminating welding beads obtained by melting and solidifying a filler material while moving a welding torch. an extraction means for extracting the trajectory of the welding torch, and an operation for calculating, based on the trajectory, the coordinate information of the moving space through which the welding torch passes and the coordinate information of the exclusion space in which the already laminated welding bead excludes the welding torch from entering. determining means for determining whether there is a spatial overlap between the moving space and the excluded space based on the coordinate information of the excluded space and the coordinate information of the moving space; and determining that there is a spatial overlap. generating means for generating an instruction to replace the welding torch or parts of the welding torch so that the welding torch has a smaller diameter when the welding torch becomes smaller.

Furthermore, the present invention provides a computer that controls a layered manufacturing system for manufacturing a layered manufacturing object by stacking welding beads obtained by melting and solidifying a filler material while moving a welding torch, and a layering plan for a layered manufacturing object. and based on the trajectory, calculate the coordinate information of the moving space through which the welding torch passes and the coordinate information of the exclusion space where the welding bead already laminated prevents the welding torch from entering. a function to determine whether there is a spatial overlap between the moving space and the excluded space based on the coordinate information of the excluded space and the coordinate information of the moving space; and a function to determine that there is a spatial overlap. Also provided is a program for realizing a function of generating a command to replace the welding torch or parts of the welding torch so that the diameter of the welding torch becomes smaller.

Advantageous Effects of Invention According to the present invention, it is possible to manufacture a laminate-molded object while optimizing the replacement frequency of a welding torch or a welding torch component in a laminate-molding system that molds a laminate-molded object.

BRIEF DESCRIPTION OF THE DRAWINGS It is the figure which showed the schematic structural example of the metal additive manufacturing system to which embodiment of this invention is applicable. It is a figure which shows the hardware structural example of the control apparatus in embodiment of this invention. 1 is a diagram showing a functional configuration example of a stacking planning device according to an embodiment of the present invention; FIG. (a) is a diagram showing an example of layer shape data, and (b) is a diagram showing an example of a lamination pass for this layer shape data. (a) is a diagram showing the excluded space before the area is added, and (b) is a diagram showing the excluded space after the area is added. FIG. 4 is a diagram showing an example of interference by a welding torch; FIG. 10 is a diagram for explaining a change in the pass order of stacking passes; 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 the flow of nozzle replacement determination processing performed by the stacking planning device according to the embodiment of the present invention. 4 is a flow chart showing an operation example 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 the laminate-molded article 100 at the tip of the arm 11 via the wrist portion 12 . 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”) are stacked to manufacture the 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 welding robot 10 also has a shape sensor 15 at the tip of the arm 11 . The shape sensor 15 measures the cross-sectional shape of the bead actually laminated by the welding robot 10 . Since the temperature of the bead immediately after formation is high, it is preferable to use a non-contact measurement method such as laser measurement as a method for measuring the shape of the bead. In this embodiment, the shape sensor 15 is provided as an example of measuring means for measuring the shape of the welding bead already laminated.

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”).

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 a bead under the determined welding conditions along the determined trajectory is then generated, and the control program is output to the recording medium 70 . In this embodiment, a lamination planning device 30 is provided as an example of a computer that controls the lamination manufacturing system.

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. The welding robot 10 is controlled to form

[Hardware configuration of lamination planning device]
FIG. 2 is a diagram showing a hardware configuration example of the stacking planning device 30. As shown in FIG.

As illustrated, the stacking planning apparatus 30 is realized by, for example, a general-purpose PC (Personal Computer) or the like, and includes a CPU 31 as computing means, a main memory 32 and a magnetic disk device (HDD: Hard Disk Drive) 33 as storage means. and Here, the CPU 31 executes various programs such as an OS (Operating System) and application software to realize each function of the stacking planning device 30 . The main memory 32 is a storage area for storing various programs and data used for their execution, and the magnetic disk device 33 is a storage area for storing input data to various programs and output data from various programs. .

The stacking planning device 30 also has a communication I/F 34 for communicating with the outside, a display mechanism 35 including a video memory, a display, etc., an input device 36 such as a keyboard and a mouse, and a recording medium 70. and a driver 37 for reading and writing data. It should be noted that FIG. 2 merely illustrates a hardware configuration when the stacking planning device 30 is realized by a computer system, and the stacking planning device 30 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 control device 50 . However, when describing the control device 50, the CPU 31, the main memory 32, the magnetic disk device 33, the communication I/F 34, the display mechanism 35, the input device 36, and the driver 37 in FIG. A device 53 , a communication I/F 54 , a display mechanism 55 , an input device 56 and a driver 57 are used.

[Background and outline of the present embodiment]
In the metal additive manufacturing system 1 having such a configuration, when laminating beads while moving the welding torch 13, the penetration of the welding torch 13 may be hindered depending on the shape of the existing bead.

Therefore, in the present embodiment, based on the trajectory of the lamination pass obtained from the lamination plan, a moving space through which the welding torch 13 passes and an exclusion space in which the existing bead excludes the welding torch 13 from entering are calculated. . Then, when there is an overlapping portion in these spaces, the diameter of the welding torch 13 is controlled to be smaller. Also, if the overlapping portion is not resolved even if the diameter of the welding torch 13 is made smaller, control is performed so as to change the order of the stacking passes.

[Details of this embodiment]
Hereinafter, the metal additive manufacturing system 1 realizing such an outline will be described in detail, focusing on the configuration and operation of the additive planning device 30 and the control device 50 . Here, as an example of reducing the diameter of the welding torch 13, a case will be described in which the nozzle of the welding torch 13, which is an example of the welding torch component, is replaced with one having a smaller diameter. In particular, a case where nozzles with two diameter sizes are prepared as the nozzle of the welding torch 13 will be described as an example.

(Functional configuration of lamination planning device)
FIG. 3 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 acquisition unit 41, a CAD data dividing unit 42, a stacking planning unit 43, a nozzle replacement determination unit 44, a control program generation unit 45, and a control program 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 generates a lamination plan including the position of the welding torch 13 and welding conditions when welding beads that match the height and width of each layer of the plurality of layer shape data generated by the CAD data dividing unit 42. . Generating such a layup plan requires a model that approximates the cross-sectional shape of the bead as well as the height and width of the bead. 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. For example, while varying the amount of welding by varying the welding speed and wire feed rate under several conditions, bead-on-plate welding and vertical lamination of several layers were performed, and the height and width of each layer were measured under each condition. database. Then, the welding speed and the amount of welding that satisfy the desired height and width of lamination are selected when laminating, the estimated shape of each layer is calculated from the measurement results as needed, and the 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 addition, as will be described later, the stacking plan unit 43 corrects the order of the stacking passes and regenerates the stacking plan when the overlap determining unit 443 instructs to correct the stacking pass order. In this embodiment, this function of the stacking planning section 43 is provided as an example of correcting means for correcting the order of stacking passes in order to reduce the number of times of replacement work.

Based on the layering plan generated by the layering planning unit 43, the nozzle replacement determining unit 44 performs processing such as determining whether or not the nozzle of the welding torch 13 needs to be replaced with one having a smaller diameter.

Specifically, the nozzle replacement determination unit 44 includes a trajectory extraction unit 441 , a space generation unit 442 , and an overlap determination unit 443 .

The trajectory extraction unit 441 extracts the trajectory of each stacking pass from the stacking plan generated by the stacking planning unit 43 . Here, the trajectory of each stacking path may be, for example, a set of coordinate information of points through which each stacking path passes. In the present embodiment, a trajectory extraction unit 441 is provided as an example of extraction means for extracting the trajectory of the lamination pass from the lamination plan of the laminate-molded article.

FIG. 4(a) shows an example of layer shape data (slice data), and FIG. 4(b) shows an example of lamination paths for this layer shape data. The layer shape data of FIG. 4( a ) consists of a wall portion 110 and overhang portions 120 and 130 projecting laterally from the wall portion 110 . A hollow portion 140 is formed between the wall portion 110 and the overhang portions 120 and 130 . The stacking passes shown in FIG. 4B include stacking passes 111a to 111e for forming the wall portion 110, stacking passes 121a to 121d and 131a to 131f for forming the overhang portions 120 and 130, respectively, and a lamination pass 141 for forming a portion of the wall 110 sandwiched between the overhangs 120 and 130 . Here, the stacking paths 111a to 111e, 121a to 121d, 131a to 131f, and 141 are stacked in this order, for example. Also, the trajectories of the stacking passes 111a to 111e, 121a to 121d, and 131a to 131f are the trajectories of the existing beads, and the trajectory of the stacking pass 141 is the trajectory to which the welding torch 13 will move. This is represented by the former being indicated by a solid line arrow and the latter being indicated by a dashed line arrow.

The space generation unit 442 calculates, from the trajectory of each lamination pass extracted by the trajectory extraction unit 441, a movement space through which the welding torch 13 passes during lamination and an exclusion space through which the existing bead excludes the welding torch 13 from entering. Generate. In this embodiment, the space generator 442 is provided as an example of a computing means for computing the coordinate information of the moving space and the coordinate information of the excluded space based on the trajectory.

For example, the space generation unit 442 uses software having a function to draw a three-dimensional shape of the moving space of the welding torch 13 and the exclusion space of the existing bead on the slice data and the trajectory of the lamination pass shown in FIG. It may be generated by applying a figure simulating a bead.

Further, the space generation unit 442 easily generates the movement space of the welding torch 13 by adding a width corresponding to the inclination angle of the welding torch 13 at the time of stacking and the diameter of the nozzle to the trajectory of the welding torch 13. You may In addition, the space generation unit 442 may generate a movement space for the welding torch 13 by adding a clearance to the generated movement space.

In addition, the space generation unit 442 adds a simple bead model shape such as an ellipse or a trapezoid according to the planned width and height of the bead to the locus of the bead for the exclusion space of the existing bead. can be generated automatically.

Furthermore, as shown in FIG. 5, the space generation unit 442 may generate the existing bead exclusion space by adding a region according to the angle formed by the locus of the bead. FIG. 5(a) shows the excluded space 152 before the regions are added. Exclusion space 152 includes exclusion space 112e and exclusion space 132f. Here, the excluded space 112e is the excluded space generated by adding the model shape of the bead to the stacking pass 111e, and the excluded space 132f is the excluded space generated by adding the model shape of the bead to the stacking pass 131f. Space. It is assumed that the stacking path 111e and the stacking path 131f intersect at an acute angle θ. FIG. 5(b) shows the excluded space 162 after the regions have been added. The exclusion space 162 is obtained by adding the region 133 to the acute angle θ formed by the exclusion space 112e and the exclusion space 132f.

Furthermore, the space generator 442 may set the width given to the trajectory of the welding torch 13 and the trajectory of the existing bead based on the interval between the trajectories of the stacking passes. In addition, the space generation unit 442 may provide an element shape model of the bead laminate prepared in advance for the trajectories of a plurality of lamination passes. Here, the element shape model of the bead laminate may be, for example, a model of a wall, a block, an overhang, etc. consisting of a plurality of beads.

The overlap determination unit 443 determines overlap between the moving space of the welding torch 13 and the exclusion space of the existing bead, thereby extracting a stacking path in which the welding torch 13 and the laminate-molded article 100 are likely to interfere. For example, the overlap determination unit 443 may determine overlap between the moving space and the excluded space by checking the coordinate information for the presence or absence of points belonging to both the moving space and the excluded space. At this time, the overlap determination unit 443 can exhaustively examine interference that may occur during modeling by determining overlap in the stacking order of the stacking passes. In the present embodiment, the overlap determination unit 443 is used as an example of determination means for determining whether there is a spatial overlap between the moving space and the excluded space based on the coordinate information of the excluded space and the coordinate information of the moving space. are provided.

FIG. 6 shows an example of interference by the welding torch 13. As shown in FIG. 6 shows existing bead exclusion spaces 112a to 112e in the wall portion 110, existing bead exclusion spaces 122a to 122d in the overhang portion 120, and existing bead exclusion spaces 132a to 132f in the overhang portion 130. ing. Also, FIG. 5 only shows that the region 133 is added to the acute angle portion formed by the exclusion space 112e and the exclusion space 132f, but FIG. It also shows that a region 123 is added to . Further, FIG. 6 also shows a moving space 142 from which the welding torch 13 moves. In this case, the movement space 142 and the area 123 do not overlap, but the movement space 142 and the area 133 overlap. That is, the welding torch 13 and the layered product 100 interfere in the area 133 when the welding torch 13 moves on the layering path 141 .

The overlap determination unit 443 replaces the nozzle of the welding torch 13 with a nozzle having a smaller diameter before the stacking pass in order to avoid interference in the stacking pass in which the welding torch 13 and the laminate-manufactured article 100 interfere. The control program generator 45 is instructed to set a nozzle replacement command. In addition, in order to confirm whether or not interference can be avoided after replacing the nozzle, the overlap determination unit 443 repeats the space generation by the space generation unit 442 and the overlap determination by the overlap determination unit 443 using the nozzle diameter after replacement. may be controlled to do so. By exchanging the nozzle in this way to avoid interference between the welding torch 13 and the laminate-molded article 100, it is possible to suppress the occurrence of device errors and defects during modeling without correcting the welding conditions of the trajectory and bead. .

Furthermore, since the productivity decreases as the number of nozzle replacements increases, the duplication determination section 443 may instruct the stacking planning section 43 to correct the pass order of the stacking passes so as to reduce the number of nozzle replacements. In this case, if the interference cannot be avoided by exchanging nozzles, the overlap determination unit 443 may instruct the stacking planning unit 43 to correct the pass order of the stacking passes.

For example, when judging overlap by applying a plurality of lamination paths to an element shape model of a bead laminate prepared in advance, the overlap determination unit 443 determines the stacking order by using the element shape model of the bead laminate as a unit. good. Here, the element shape model of the bead laminate may be, for example, a model of a wall, block, overhang, or the like consisting of a plurality of beads, as described above. If the lamination order is set with the element shape model of the bead laminate as a unit, the total number of combinations of orders is reduced when the number of lamination passes of the laminate-molded article 100 is large, and an appropriate lamination order can be searched efficiently. . Note that the overlap determination unit 443 may fix the stacking order for a plurality of stacking paths in the element shape model of the bead stack.

Referring to FIG. 7, changing the pass order of the stacking passes will be described. Assume that the stacking paths 111a to 111e, 121a to 121d, 131a to 131f, and 141 are stacked in this order in the initial stacking plan. In this case, since the stacking pass 141 is stacked after the stacking passes 131a to 131f are stacked, the moving space 142 and the area 133 overlap. Therefore, it is preferable to change the pass order of the stacking passes so that the stacking passes 131a to 131f are stacked after the stacking pass 141 is stacked.

Alternatively, if there are a plurality of stacking passes that require nozzles with a small diameter, the overlap determination unit 443 continuously stacks these stacking passes, and then performs the stacking passes using nozzles with a normal size nozzle. You may make it laminate|stack. This reduces the frequency of nozzle replacement.

The control program generation unit 45 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 . In the present embodiment, this function of the control program generator 45 is provided as an example of first control means for controlling the welding bead to be laminated while moving the welding torch.

In addition, the control program generation unit 45 controls when the duplication determination unit 443 instructs to set a nozzle replacement command to replace the nozzle of the welding torch 13 with one having a smaller diameter before the stacking pass in which interference occurs. Set the nozzle replacement command in the program. In the present embodiment, as an example of a generating means for generating a command to replace a welding torch part so that the diameter of the welding torch becomes smaller when it is determined that there is a spatial overlap, the control program generation unit 45 provides this function. Further, in the present embodiment, when the welding torch and the laminated welding bead interfere with each other, the second control means performs control so that the welding torch parts are replaced so that the diameter of the welding torch becomes smaller. This function of the control program generation unit 45 is provided as an example of .

The control program output unit 46 outputs the control program generated by the control program generation unit 45 to the recording medium 70 .

(Functional configuration of control device)
FIG. 8 is a diagram showing a functional configuration example of the control device 50 in this embodiment. As illustrated, the control device 50 in this embodiment includes a control program acquisition section 61 , a control program storage section 62 , a shape data reception section 63 and a control program execution section 64 .

The control program acquisition unit 61 acquires the control program recorded on the recording medium 70 .

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

The shape data receiving unit 63 sequentially receives shape data indicating the measured shape from the shape sensor 15 that measures the shape of the laminated bead.

The control program execution unit 64 reads and executes the control program stored in the control program storage unit 62 . Thereby, the control program executing section 64 controls the welding robot 10 to form a bead according to the lamination plan generated by the lamination planning section 43 . In particular, when a nozzle replacement command is set to replace the nozzle of the welding torch 13 with one having a smaller diameter, the control program execution unit 64 replaces the nozzle with a nozzle having a smaller diameter at a nozzle replacement station (not shown). Thus, the welding robot 10 is controlled. In that case, it is preferable to add to the control program the coordinate information of the movement space and the exclusion space that served as the basis for the decision to replace the nozzle with a nozzle having a smaller diameter. Also, the control program executing section 64 may change the excluded space based on the shape data received by the shape data receiving section 63 . In this embodiment, this function of the control program execution unit 64 is provided as an example of changing means for changing the coordinate information of the excluded space based on the measured shape.

(Operation of lamination planning device)
FIG. 9 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 nozzle replacement determination unit 44 executes nozzle replacement determination processing for determining whether or not the nozzle of the welding torch 13 should be replaced with one having a smaller diameter (step 304). The details of this nozzle replacement determination process will be described later.

Next, the stacking plan unit 43 determines the pass order of the two stacking passes for which the pass order correction flag indicating whether the pass order should be corrected in the nozzle replacement determination process is set to ON in the stacking plan generated in step 303. Modify (step 305).

Next, the control program generator 45 generates a control program based on the stacking plan generated in step 303 or the stacking plan generated in step 303 and modified in step 305 (step 306). Specifically, a control program is generated that controls the welding robot 10 to form a bead according to the lamination plan.

Next, in the control program generated in step 306, the control program generating unit 45 generates a nozzle change flag for a stacked pass in which the nozzle change flag indicating whether or not the nozzle should be changed to a nozzle with a smaller diameter in the nozzle change determination process. An exchange command is set (step 307). Specifically, the control program generation unit 45 sets a nozzle replacement command to replace the nozzle with a smaller diameter nozzle for the stacking pass in which the nozzle replacement flag is switched from OFF to ON. In addition, the control program generation unit 45 sets a nozzle replacement command to replace the nozzle with a larger diameter nozzle for the stacking pass in which the nozzle replacement flag is switched from ON to OFF.

Alternatively, the control program generation unit 45 may replace the nozzle with a larger diameter nozzle even if the nozzle replacement flag is switched from ON to OFF in the stacking pass, that is, the operation of returning the nozzle to its original state may not be performed. . The control program generator 45 may use a stacking pass arbitrarily determined by the operator from the stacking plan as the stacking pass for returning the nozzle. A stacking pass determined by comparing the work load in the case of returning the nozzle to the original state may be used.

The work load when the nozzle is not put back and the work load when the nozzle is put back are calculated by the following equations.
(work load if the nozzle is not put back) = (expected number of cleanings for the smaller nozzle) x (time required for one cleaning for the smaller nozzle)
(work load when replacing the nozzle) = (time required for one nozzle replacement) + (estimated number of cleanings for a nozzle with a larger diameter) x (time required for one cleaning for a nozzle with a larger diameter) )

Here, the estimated number of nozzle cleanings may be estimated based on the number of remaining stacking passes and past nozzle replacement frequency records. In addition, the time required for one cleaning of the nozzle and the time required for one replacement of the nozzle may be obtained by referring to past performance values.

When the timing of returning the nozzle is flexibly determined in this way, the work load of cleaning and replacement is compared, so unnecessary wear of the nozzle parts can be suppressed.

Finally, the control program output unit 46 outputs the control program generated in step 306 or the control program generated in step 306 and set with the nozzle replacement command in step 307 to the recording medium 70 (step 308). .

FIG. 10 is a flow chart showing the flow of nozzle replacement determination processing in step 304 of FIG. In the initial state, both the nozzle replacement flag Fn(i) and the pass order correction flag Fp(i,j) are set to OFF.

In the nozzle replacement determination process, first, the trajectory extraction unit 441 extracts the trajectory of the stacking pass from the stacking plan generated in step 303 of FIG. 9 (step 351).

Next, the trajectory extraction unit 441 sets the stacking path index i to 2 (step 352). In other words, focus on the second stacking pass.

Next, the trajectory extraction unit 441 increments the lamination path index i by 1 up to the number n of lamination paths, and performs the processing of steps 353 to 361 for each index i.

That is, the space generation unit 442 first generates the movement space St(i) and the exclusion spaces Sb(1) to Sb(i−1) based on the trajectory of the stacking path extracted in step 351 ( step 353). Here, the moving space St(i) is a moving space through which the welding torch 13 passes when forming a bead in the i-th stacking pass. The exclusion space Sb(j) (j=1, 2, . . . , i−1) is the exclusion space in which the bead already formed in the j-th stacking pass excludes the welding torch 13 from entering. In the excluded spaces Sb(1) to Sb(i−1), special angles formed by the excluded spaces in each stacking pass, such as the regions 123 and 133 shown in FIG. Areas shall also be included. Further, the space generation unit 442 may use the excluded spaces Sb(1) to Sb(i−2) generated by the processing for the index i so far, but here, the excluded space Sb( 1) to Sb(i−1) are newly generated to include the above region.

Next, the duplication determination unit 443 sets the index j of the lamination path on which a bead has already been formed (hereinafter referred to as "bead forming path") to 1 (step 354). That is, attention is focused on the first bead forming pass.

Next, the duplication determination unit 443 performs the processing of steps 355 to 359 for each index j while incrementing the index j of the bead forming pass by 1 until the number of bead forming passes i−1.

That is, the overlap determination unit 443 determines whether or not the moving space St(i) generated in step 353 overlaps with the excluded space Sb(j) (step 355).

If it is determined in step 355 that the moving space St(i) and the exclusion space Sb(j) overlap, the space generation unit 442 replaces the nozzle with a smaller diameter moving space St( i) is generated (step 356). Note that if the movement space St(i) after replacing the nozzle with a smaller diameter nozzle has already been generated in the processing for the index j so far, this processing may be skipped.

Next, the overlap determination unit 443 determines whether or not the moving space St(i) generated in step 356 overlaps the excluded space Sb(j) generated in step 353 (step 357). That is, it is determined whether the duplication determined in step 355 has been resolved.

If it is determined in step 357 that the moving space St(i) and the excluded space Sb(j) do not overlap, that is, if it is determined that the overlap has been resolved, the overlap determining unit 443 sets the nozzle replacement flag Fn (i) is set to ON (step 358). Here, when the nozzle replacement flag Fn(i) is ON, the welding torch 13 of the i-th stacking pass interferes with any of the existing beads of the stacking passes up to the (i-1)th stacking pass. indicates that the nozzle should be replaced with a smaller diameter nozzle. Note that if the nozzle replacement flag Fn(i) has already been turned ON in the processing for the index j so far, this processing may be skipped.

If it is determined in step 357 that the moving space St(i) and the excluded space Sb(j) overlap, that is, if it is determined that the overlap has not been resolved, the overlap determining unit 443 determines, for example, the pass order A correction flag Fp(i, j) is set to ON (step 359). Here, when the pass order correction flag Fp(i, j) is ON, the welding torch 13 in the i-th stacking pass interferes with the existing bead in the j-th stacking pass, and interference occurs even if the nozzle is replaced. cannot be avoided, the order of the i-th stacking pass and the j-th stacking pass should be corrected.

After that, the overlap determination unit 443 adds 1 to the index j of the bead forming pass (step 360). That is, attention is focused on the next bead forming pass. Then, it is determined whether or not the bead forming pass index j exceeds the number of bead forming passes i−1 (step 361).

As a result, if it is determined that the index j of the bead forming pass does not exceed the number i−1 of the bead forming passes, the duplication determination section 443 returns the process to step 355 .

On the other hand, if it is determined that the index j of the bead forming pass has exceeded the number i−1 of the bead forming passes, the duplication determination section 443 advances the process to step 362 .

After that, the trajectory extraction unit 441 adds 1 to the index i of the lamination path (step 362). In other words, focus on the next stacking pass. Then, it is determined whether or not the lamination pass index i exceeds the number n of lamination passes (step 363).

As a result, if it is determined that the lamination pass index i does not exceed the number n of lamination passes, the trajectory extraction unit 441 returns the process to step 353 .

On the other hand, if it is determined that the stacking path index i exceeds the number of stacking paths n, the trajectory extraction unit 441 returns the process to FIG.

(Operation of control device)
In the control device 50 , first, the control program acquisition section 61 acquires the control program from the recording medium 70 and stores it in the control program storage section 62 . In this state, when the laminate-molded article 100 is actually formed using the welding robot 10, the shape data receiving unit 63 receives shape data indicating the shape of the bead from the shape sensor 15, while the control program executing unit 64 reads the control program stored in the control program storage unit 62 and executes it.

FIG. 11 is a flow chart showing an operation example of the control program execution section 64. As shown in FIG. Here, an operation example of the control program execution unit 64 at the time of forming a bead by moving the welding torch 13 in the i-th stacking pass is shown. Also, the control program is added with the coordinate information of the moving space and the exclusion space that served as the basis for deciding to replace the nozzle of the welding torch 13 with one having a smaller diameter.

The control program execution unit 64 first acquires the movement space St(i) and the exclusion spaces Sb(1) to Sb(i−1) from the control program (step 501). Here, the moving space St(i) is a moving space through which the welding torch 13 passes when forming a bead in the i-th stacking pass. The exclusion space Sb(j) (j=1, 2, . . . , i−1) is the exclusion space in which the bead already formed in the j-th stacking pass excludes the welding torch 13 from entering. In the excluded spaces Sb(1) to Sb(i−1), special angles formed by the excluded spaces in each stacking pass, such as the regions 123 and 133 shown in FIG. Areas shall also be included.

Next, the control program execution unit 64 sets the index j of the bead forming pass, which is a stacking pass on which a bead has already been formed, to 1 (step 502). That is, attention is focused on the first bead forming pass.

Next, the control program execution unit 64 performs the processing of steps 503 to 510 for each index j while incrementing the index j of the bead forming pass by 1 until the number of bead forming passes i−1.

That is, the control program execution unit 64 first determines whether or not the excluded space Sbr(j) has been acquired from the shape data reception unit 63 (step 503). Here, the excluded space Sbr(j) may be the shape of the existing bead in the j-th bead forming pass obtained from the shape data receiving section 63 . This determination is made because it is not possible to acquire the shape of the existing bead in all bead forming passes when forming a bead with the welding torch 13 .

If it is determined in step 503 that the excluded space Sbr(j) has been acquired, the control program execution unit 64 determines whether or not this excluded space Sbr(j) deviates from the excluded space Sb(j) acquired in step 501. is determined (step 504). That is, the control program execution unit 64 determines whether or not the actually measured excluded space Sbr(j) deviates from the planned excluded space Sb(j).

If it is determined in step 504 that the excluded space Sbr(j) deviates from the excluded space Sb(j), the control program execution unit 64 determines the moving space St(i) obtained in step 501 and the moving space St(i) obtained in step 503. It is determined whether or not the excluded space Sbr(j) overlaps (step 505).

If it is determined in step 505 that the moving space St(i) and the exclusion space Sbr(j) overlap, the control program execution unit 64 determines whether or not the nozzle of the welding torch 13 can be replaced (step 506). ). That is, the control program execution unit 64 determines whether the nozzle currently attached to the welding torch 13 is the nozzle with the smaller diameter of the two types of nozzles prepared.

If it is determined in step 506 that the nozzle of the welding torch 13 is replaceable, the control program execution unit 64 generates the movement space St(i) after replacing the nozzle with a smaller diameter nozzle (step 507). .

Next, the control program execution unit 64 determines whether or not the movement space St(i) generated in step 507 and the excluded space Sbr(j) obtained in step 503 overlap (step 508). . That is, it is determined whether the duplication determined in step 505 has been resolved.

If it is determined in step 508 that the moving space St(i) and the exclusion space Sbr(j) do not overlap, that is, if it is determined that the overlap has been resolved, the control program execution unit 64 causes the nozzle of the welding torch 13 is replaced with one having a smaller diameter (step 509), and the process proceeds to step 511.

Also when it is determined in step 503 that the excluded space Sbr(j) has not been obtained, the control program execution unit 64 advances the process to step 511 . Also when it is determined in step 504 that the excluded space Sbr(j) is not separated from the excluded space Sb(j), the control program executing section 64 advances the process to step 511 . Also when it is determined in step 505 that the moving space St(i) and the exclusion space Sbr(j) do not overlap, the control program executing section 64 advances the process to step 511 .

On the other hand, if it is determined in step 506 that the nozzle of welding torch 13 is not replaceable, control program execution unit 64 outputs an error (step 510) and ends the process. If it is determined in step 508 that the moving space St(i) and the excluded space Sbr(j) overlap, that is, if it is determined that the overlap has not been resolved, the control program execution unit 64 outputs an error. (step 510), and the process ends.

After that, the control program execution unit 64 adds 1 to the index j of the bead forming pass (step 511). That is, attention is focused on the next bead forming pass. Then, it is determined whether or not the bead forming pass index j exceeds the number of bead forming passes i−1 (step 512).

As a result, if it is determined that the index j of the bead forming pass does not exceed the number i−1 of bead forming passes, the control program executing section 64 returns the process to step 503 .

On the other hand, if it is determined that the index j of the bead forming pass has exceeded the number i−1 of the stacking passes, the control program execution unit 64 controls the welding robot 10 to form a bead in the i-th stacking pass (step 513), the process ends.

[Modification]
In the above description, nozzles with two diameter sizes are prepared, and if the nozzle with the larger diameter interferes with the welding torch 13 and the laminate-molded article 100, the nozzle with the smaller diameter is exchanged. However, it is not limited to this. A process of preparing nozzles of a plurality of sizes and replacing them with nozzles of one step smaller diameter when using a nozzle of a large diameter interferes with the welding torch 13 and the laminate-molded article 100 may be repeated. good.

Moreover, in the above description, the nozzle of the welding torch 13 is replaced with one having a smaller diameter in order to make the diameter of the welding torch 13 smaller, but this is not the only option. In order to make the diameter of the welding torch 13 smaller, the welding torch 13 may be replaced, such as by replacing the torch for tandem arc welding with a torch for single arc welding.

[Effects of this embodiment]
As described above, in the present embodiment, when there is an overlapping portion between the moving space through which the welding torch 13 passes and the exclusion space in which the existing bead excludes the welding torch 13 from entering, the nozzle of the welding torch 13 was replaced with a smaller diameter one. As a result, in the metal additive manufacturing system 1 that models the laminate-molded article 100 , the laminate-molded article 100 can be modeled by using a minimum necessary nozzle with a small diameter as the nozzle of the welding torch 13 .

DESCRIPTION OF SYMBOLS 1... Metal additive manufacturing system, 10... Welding robot, 15... Shape sensor, 20... CAD device, 30... Lamination planning device, 41... CAD data acquisition part, 42... CAD data division part, 43... Lamination planning part, 44... Nozzle replacement determination unit 441 Trajectory extraction unit 442 Space generation unit 443 Overlap determination unit 45 Control program generation unit 46 Control program output unit 50 Control device 61 Control program acquisition unit 62 ... control program storage unit, 63 ... shape data reception unit, 64 ... control program execution unit, 70 ... recording medium

Claims (8)

A control method for a layered manufacturing system for manufacturing a layered product by stacking welding beads obtained by melting and solidifying a filler material while moving a welding torch,
an extraction step of extracting a trajectory of a lamination pass from the lamination plan of the lamination-molded article;
a computing step of computing, based on the trajectory, coordinate information of a moving space through which the welding torch passes and coordinate information of an exclusion space in which the already laminated welding bead excludes entry of the welding torch;
a determination step of determining whether or not there is a spatial overlap between the moving space and the excluded space based on the coordinate information of the excluded space and the coordinate information of the moving space;
and a generating step of generating an instruction to replace the welding torch or the welding torch part so that the diameter of the welding torch becomes smaller when it is determined that there is the spatial overlap. A control method for an additive manufacturing system. 2. The method of controlling an additive manufacturing system according to claim 1, further comprising a modifying step of modifying the order of the stacking passes to reduce the number of replacement operations. a measuring step of measuring the shape of the already laminated welding bead while moving the welding torch;
2. The control method of the additive manufacturing system according to claim 1, further comprising a changing step of changing the coordinate information of the excluded space based on the measured shape. In the calculating step, the moving space is calculated by applying a prepared model figure based on at least one of the inclination angle of the welding torch, the diameter of the welding torch, and the arrangement of the trajectory to the trajectory. The control method of the laminate manufacturing system according to claim 1, characterized by: In the calculating step, by applying to the trajectory a model graphic prepared in advance based on at least one of the width of the welding bead, the height of the welding bead, the angle formed by the trajectory, and the arrangement of the trajectory, 2. The control method of the additive manufacturing system according to claim 1, wherein the exclusion space is calculated. A control method for a layered manufacturing system for manufacturing a layered product by stacking welding beads obtained by melting and solidifying a filler material while moving a welding torch,
a first control step of controlling the welding bead to be stacked while moving the welding torch;
a second control step of performing control to replace the welding torch or welding torch parts so that the diameter of the welding torch becomes smaller when the welding torch and the laminated welding bead interfere with each other; A control method for an additive manufacturing system, comprising: A layered manufacturing system for manufacturing a layered product by stacking welding beads obtained by melting and solidifying a filler material while moving a welding torch,
Extraction means for extracting a trajectory of a lamination pass from the lamination plan of the lamination-molded article;
computing means for computing coordinate information of a moving space through which the welding torch passes and coordinate information of an exclusion space in which the already laminated welding bead excludes the welding torch from entering, based on the trajectory;
determination means for determining whether or not there is a spatial overlap between the moving space and the excluded space based on the coordinate information of the excluded space and the coordinate information of the moving space;
generating means for generating an instruction to replace the welding torch or welding torch parts so that the diameter of the welding torch becomes smaller when it is determined that there is the spatial overlap. and additive manufacturing system. A computer that controls a layered manufacturing system that forms a layered product by layering welding beads that melt and solidify the filler material while moving the welding torch,
A function of extracting the trajectory of the lamination pass from the lamination plan of the lamination-molded article;
A function of calculating coordinate information of a moving space through which the welding torch passes and coordinate information of an exclusion space in which the already laminated welding bead excludes entry of the welding torch, based on the trajectory;
a function of determining whether there is a spatial overlap between the moving space and the excluded space based on the coordinate information of the excluded space and the coordinate information of the moving space;
a program for realizing a function of generating a command to replace the welding torch or welding torch parts so that the diameter of the welding torch becomes smaller when it is determined that there is the spatial overlap; .

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