JP2024067526A - CONTROL INFORMATION GENERATION DEVICE, CONTROL INFORMATION GENERATION METHOD, PROGRAM, WELDING DEVICE, AND WELDING METHOD - Google Patents

Abstract

[Problem] To provide a control information generating device, a control information generating method, a program, and a welding device and a welding method for additive manufacturing, which can suppress the occurrence of unwelded portions due to gaps occurring inside bends even when paths for bead formation have bend corners that intersect with each other at bend angles. [Solution] A control information generating device 200 includes a target position information acquiring unit 31 that acquires information on multiple target positions for bead formation in a molding path, a bend angle calculating unit 33 that extracts bend corners of the molding path from the multiple target positions and determines the bend angles of the extracted bend corner parts, a target position interval correcting unit 35 that corrects the intervals between multiple target positions arranged in an inner area sandwiched between the molding paths of the bend corner parts, a molding path correcting unit 37 that corrects the molding path so that the intervals between the target positions are increased as the bend angle of the bend corner part becomes smaller, and a control information generating unit 39 that generates control information including information on the corrected molding path. [Selected Figure] Figure 2

Description

The present invention relates to a control information generating device, a control information generating method, a program, and a welding device and a welding method.

In recent years, there has been an increasing need for 3D printers as a means of production, and research and development is underway to commercialize 3D printers that use metal materials. 3D printers use heat sources such as lasers, electron beams, and even arcs to melt metal powder or metal wire, and then laminate the molten metal to produce objects.

As an example of such a modeling technique, Patent Document 1 discloses an additive manufacturing device that layers molten processing material to form a three-dimensional shape. The additive manufacturing device melts the processing material and arranges beads on the processing target surface to form a layer shape while moving the processing position along a modeling path (also called a "path") indicated by control information, and then layers this layer shape to form the desired three-dimensional shape. During modeling, a correction width for the bead width is calculated based on the bead formation path and the reference width of the bead cross section, and beads are formed along a corrected path corrected based on this correction width, thereby suppressing deterioration in modeling quality due to bead overlap.

Patent No. 6647480

In the case of forming a three-dimensional shape by additive manufacturing as described above, as shown in FIG. 16A, bend corners may exist between paths PS_1 and PS_2, and paths PS_3 and PS_4 of the bead. In such cases, gaps SP are formed between the outer paths (PS_1, PS2) and the inner filled paths (PS_3, PS_4) in the inner regions of the bend corners, making it easier for unwelded areas to occur. This is because the outer edge of the bead B that is formed is rounded on the outside of the path corners, while forming sharp corners on the inside. As shown in FIG. 16B, the smaller the bend angle where paths PS1 and PS2 intersect, and the bend angle where paths PS3 and PS4 intersect, the more noticeable the gaps SP are.

In order to avoid the occurrence of such a gap SP, it is conceivable to simply extend the bead formation path to fill the gap SP. However, since this filling involves filling a narrow portion with a bead B, if the welding conditions are not appropriately adjusted, the amount of deposition is likely to be excessive. As a result, as shown in Figure 17, problems such as the bead height H at the bend corner portion being likely to be higher than the bead height _H0 at other portions occur.

The present invention aims to provide a control information generating device, a control information generating method, a program, and a welding device and method for additive manufacturing that can prevent the occurrence of unwelded areas due to gaps that occur inside bends, even when the bead formation path has a bend at an intersection.

The present invention comprises the following configurations.
(1) A control information generation device that generates control information for controlling an additive manufacturing device that forms a layer shape using a bead formed by adding a molten processing material to a processing target surface while moving a processing position along a modeling path, and laminates the layer shapes to model a three-dimensional shape of a desired object, the control information generation device comprising:
a target position information acquisition unit that acquires information on a plurality of target positions for bead formation in the molding path;
a bend angle calculation unit that extracts bend angle portions of the modeling path from the plurality of target positions and calculates bend angles of the extracted bend angle portions;
a target position interval correction unit that corrects intervals between the target positions arranged in an inner region between the modeling paths of the bending corner portion;
a modeling path correction unit that corrects the modeling path so that the interval between the target positions is increased as the bend angle of the bend angle portion is smaller;
a control information generating unit that generates the control information including information of the corrected modeling path;
A control information generating device comprising:
(2) A control information generation method for controlling an additive manufacturing device that forms a layer shape by adding a molten processing material to a processing target surface while moving a processing position along a modeling path, and laminates the layer shapes to form a three-dimensional shape of a desired object, comprising:
Acquire information on a plurality of target positions for bead formation in the molding path;
Extracting bend corner portions of the shaping path from the plurality of target positions, and determining bend angles of the extracted bend corner portions;
Correcting intervals between the target positions arranged in an inner region of the bending corner portion sandwiched between the modeling paths;
The modeling path is modified so that the interval between the target positions is increased as the bend angle of the bend angle portion is smaller;
generating the control information including information of the modified modeling path;
A method for generating control information.
(3) A program for executing a procedure of a control information generation method for generating control information for controlling an additive manufacturing device that forms a layer shape by using a bead formed by adding a molten processing material to a processing target surface while moving a processing position along a modeling path, and laminates the layer shapes to model a three-dimensional shape of a desired object, the program comprising:
On the computer,
acquiring information on a plurality of target positions for bead formation in the modeling path;
A step of extracting bend corner portions of the shaping path from the plurality of target positions and determining bend angles of the extracted bend corner portions;
correcting intervals between the target positions arranged in an inner region of the bending corner portion sandwiched between the modeling paths;
a step of correcting the modeling path so that an interval between the target positions is increased as the bend angle of the bend angle portion is smaller;
generating the control information including information of the modified modeling path;
A program that executes the following.
(4) A control information generating device according to (1),
the additive manufacturing apparatus performing arc welding along the manufacturing path based on the control information generated by the control information generating device;
A welding device comprising:
(5) A welding method for performing arc welding along the shaping path based on control information generated by the control information generation method according to (2).

According to the present invention, even when the bead formation path has a bend corner portion where the bead crosses at a bend angle, it is possible to prevent the occurrence of unwelded portions due to gaps that occur inside the bend corner.

FIG. 1 is a diagram showing the overall configuration of an additive manufacturing apparatus. FIG. 2 is a functional block diagram of the control information generating device. FIG. 3 is a flowchart showing a procedure for generating control information. FIG. 4 is a schematic diagram of a path for explaining the basic procedure for extracting a bent corner portion. FIG. 5 is a schematic diagram of a path for explaining another procedure for extracting a bent corner portion. FIG. 6 is a graph showing a schematic distribution of bending angles with respect to the target position. FIG. 7 is a graph showing a schematic diagram of another distribution of bending angles with respect to the target position. FIG. 8A is an explanatory diagram showing a step-by-step procedure for equalizing the intervals between paths. FIG. 8B is an explanatory diagram showing a step-by-step procedure for equalizing the intervals between paths. FIG. 8C is an explanatory diagram showing a step-by-step procedure for equalizing the intervals between paths. FIG. 8D is an explanatory diagram showing a step-by-step procedure for equalizing the intervals between paths. FIG. 9A is a schematic explanatory diagram showing a process in which adjacent paths are evenly arranged in stages. FIG. 9B is a schematic explanatory diagram showing a process in which adjacent paths are evenly spaced. FIG. 9C is a schematic explanatory diagram showing a process in which adjacent paths are evenly spaced. FIG. 10 is a graph showing a schematic change in the travel distance of a path over time. FIG. 11 is a schematic explanatory diagram when the mathematical model is applied to each path. FIG. 12 is an explanatory diagram showing a state in which a repulsive force is applied between the target positions of the path at the bent corner portion and the path inside the bent corner portion shown in FIG. 4 and FIG. FIG. 13 is an explanatory diagram showing the result of changing the path position. FIG. 14A is an explanatory diagram showing paths according to a modeling plan when filling the inside of a rectangle with a bead. FIG. 14B is an explanatory diagram showing the result of optimizing the path of FIG. 14A. FIG. 15A is an explanatory diagram showing a path according to a modeling plan when filling the inside of a rectangle having a circular hole with a bead. FIG. 15B is an explanatory diagram showing the result of optimizing the path of FIG. 15A. FIG. 16A is an explanatory diagram showing a conventional bending corner portion. FIG. 16B is an explanatory diagram showing a conventional bent corner portion. FIG. 17 is an explanatory diagram showing the bead height at a conventional bend corner portion.

Below, a detailed description of an example of the configuration of the present invention will be given with reference to the drawings. Here, an example will be described in which the control information generating device of the present invention is applied to additive manufacturing, in which a layer shape is formed using a bead formed by adding molten processing material to the surface of the processing target while moving the processing position along the modeling path, and the layer shapes are stacked to form the three-dimensional shape of the desired object. The present invention can also be applied to the control of general welding such as fillet welding and butt welding.

The control information generating device generates a control signal for a welding device equipped with welding equipment such as a manipulator and a heat source to produce a welded structure. First, an example of an additive manufacturing device constituting a welding device will be described. The additive manufacturing device forms a bead by adding molten processing material to the processing target surface while moving the processing position along the printing path. This bead is used to form a layer shape, and the layer shapes are laminated to form the three-dimensional shape of the desired object.

<Additive Manufacturing Equipment>
1 is an overall configuration diagram of an additive manufacturing apparatus 100. The additive manufacturing apparatus 100 includes a modeling unit 11 and a modeling control unit 13 that controls the modeling unit 11. The control information generating device 200 may be connected to the modeling control unit 13 to configure a part of the additive manufacturing apparatus 100, or may be provided separately from the additive manufacturing apparatus 100 and connected to the modeling control unit 13 via a communication network or a storage medium. The modeling control unit 13 controls each unit of the modeling unit 11 in an integrated manner.

The modeling unit 11 includes a manipulator 17, a filler metal supply unit 19, a manipulator control unit 21, and a heat source control unit 23. The manipulator control unit 21 controls the manipulator 17 and the heat source control unit 23. A controller (not shown) is connected to the manipulator control unit 21, and any operation from the manipulator control unit 21 can be instructed by an operator via the controller.

The manipulator 17 is, for example, a multi-joint robot, and the torch 25 attached to the tip shaft supports the filler material M so that it can be continuously supplied. The torch 25 holds the filler material M protruding from the tip. The position and posture of the torch 25 can be set arbitrarily in three dimensions within the range of the degrees of freedom of the robot arm constituting the manipulator 17. The manipulator 17 is preferably one that has six or more degrees of freedom, and is preferably one that can arbitrarily change the axial direction of the heat source at the tip. The manipulator 17 may be in various forms, such as a multi-joint robot with four or more axes as shown in FIG. 1, or a robot equipped with angle adjustment mechanisms for two or more orthogonal axes.

The torch 25 has a shield nozzle (not shown), and shielding gas is supplied from the shield nozzle. The shielding gas blocks the atmosphere and prevents oxidation and nitridation of the molten metal during welding, thereby suppressing poor welding. The arc welding method used in this configuration may be either a consumable electrode type such as shielded metal arc welding or carbon dioxide gas arc welding, or a non-consumable electrode type such as TIG (Tungsten Inert Gas) welding or plasma arc welding, and is appropriately selected depending on the object to be molded. Here, gas metal arc welding is used as an example. In the case of the consumable electrode type, a contact tip is placed inside the shield nozzle, and a filler material M to which current is supplied is held by the contact tip. The torch 25 holds the filler material M and generates an arc from the tip of the filler material M in a shielding gas atmosphere.

The filler metal supply unit 19 supplies the filler metal M toward the torch 25. The filler metal supply unit 19 includes a reel 19a on which the filler metal M is wound, and a payout mechanism 19b that pays out the filler metal M from the reel 19a. The filler metal M is fed to the torch 25 by the payout mechanism 19b while being sent in the forward or reverse direction as necessary. The payout mechanism 19b is not limited to a push type that is disposed on the filler metal supply unit 19 side and pushes out the filler metal M, but may also be a pull type or push-pull type that is disposed on a robot arm or the like.

The heat source control unit 23 is a welding power source that supplies the power required for welding by the manipulator 17. The heat source control unit 23 adjusts the welding current and welding voltage supplied when forming a bead by melting and solidifying the filler metal M. In addition, the filler metal supply speed of the filler metal supply unit 19 is adjusted in conjunction with the welding conditions, such as the welding current and welding voltage, set by the heat source control unit 23.

The heat source for melting the filler material M is not limited to the arc described above. For example, other heat sources may be used, such as a heating method using both an arc and a laser, a heating method using plasma, or a heating method using an electron beam or a laser. When heating with an electron beam or laser, the amount of heat can be controlled more precisely, and the state of the bead B to be formed can be more appropriately maintained, contributing to further improving the quality of the layered product. The material of the filler material M is also not particularly limited, and the type of filler material M used may vary depending on the characteristics of the product Wk, such as mild steel, high-tensile steel, aluminum, aluminum alloy, nickel, or nickel-based alloy.

The additive manufacturing device 100 configured as described above operates according to a modeling program created based on a modeling plan for the object Wk. The modeling program is composed of a large number of command codes, and is created based on an appropriate algorithm according to various conditions such as the shape, material, and heat input of the object Wk. When the supplied filler material M is melted and solidified while moving the torch 25 according to this modeling program, a linear bead B, which is a molten solidified body of the filler material M, is formed on the base 27. In other words, the manipulator control unit 21 drives the manipulator 17 and the heat source control unit 23 based on a predetermined modeling program provided from the modeling control unit 13. The manipulator 17 moves the torch 25 while melting the filler material M with an arc, according to a command from the manipulator control unit 21, to form a bead B.

In other words, the additive manufacturing device 100 adds a filler metal M, which is a molten processing material, to the processing target surface while moving the processing position along a path, which is a modeling route set by the modeling plan, to form a bead B. Then, by repeatedly stacking the bead layers formed in a layered shape, a model Wk of the desired shape is obtained.

The modeling control unit 13 receives control information output from the control information generating device 200. This control information includes the modeling plan and modeling program information described above. The modeling control unit 13 replaces or modifies the prepared modeling program according to the input control information, and drives each part of the modeling unit 11 with the obtained modeling program to perform additive modeling.

The control information generating device 200 is configured by hardware using an information processing device such as a PC (Personal Computer). Each function of the control information generating device 200 is realized by a control unit (not shown) reading a program having a specific function stored in a storage device (not shown) and executing the program. Examples of the control unit include a processor such as a CPU (Central Processing Unit) or an MPU (Micro Processor Unit), or a dedicated circuit. Examples of the storage device include memory such as a RAM (Random Access Memory), which is a volatile storage area connected to the processor, and a ROM (Read Only Memory), which is a non-volatile storage area, as well as storage such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive).

In addition to the above-mentioned forms, the control information generating device 200 may be configured by another computer that is connected to the modeling control unit 13 from a remote location via a network or the like, as described above, or may be configured by a computer that is not directly connected to the modeling control unit 13.

<Generation of control information>
Next, a procedure for generating control information by the control information generating device 200 will be described.
2 is a functional block diagram of the control information generating device 200. The control information generating device 200 includes a target position information acquiring unit 31, a bend angle calculating unit 33, a target position interval correcting unit 35, a printing path correcting unit 37, and a control information generating unit 39. The functions of each unit will be described in detail later, but the outline thereof is as follows.

The target position information acquisition unit 31 acquires information on multiple target positions for bead formation from the modeling plan. The bend angle calculation unit 33 extracts bend angle parts of the path, which is the modeling path, from the multiple target positions and calculates the bend angle of the extracted bend angle parts. The target position interval correction unit 35 corrects the interval between multiple target positions arranged in the inner area sandwiched between the paths of the bend angle parts. The modeling path correction unit 37 corrects the path so that the interval between the target positions is increased as the bend angle of the bend angle part is smaller. The control information generation unit 39 generates control information including information on the corrected path. In addition, it is preferable that the control information generation device 200 further includes a movement amount calculation unit 41 that virtually applies a repulsive force between the multiple target positions to estimate the movement amount of the target positions.

The control information generated by the control information generation unit 39 is output to the modeling control unit 13. The modeling control unit 13 switches or changes the modeling plan based on the input control information. Then, the modeling control unit 13 controls the additive manufacturing device 100 based on the updated modeling plan to additively manufacture the desired object.

3 is a flowchart showing a procedure for generating control information. The procedure for generating control information will be described in detail below together with each component of the control information generating device 200 shown in FIG.
First, information on a modeling plan for driving the additive manufacturing apparatus 100 to additively manufacture a model is input to the control information generating device 200. The target position information acquiring unit 31 extracts a path for bead formation from the input information on the modeling plan and acquires it as information on the target position (S1). The target position here means a coordinate representing the tip position of the torch 25 when forming a bead with the tip of the torch 25, and is a plurality of points set at a predetermined interval along the path. The interval between the target positions may be a fixed interval for each path that is set, or the interval may be set according to the curvature of the path.

Next, the bend angle calculation unit 33 extracts bend angle parts of the pass from the information of the pass (target position) extracted by the target position information acquisition unit 31, and calculates the bend angles of the extracted bend angle parts (S2).
FIG. 4 is a schematic diagram of a path for explaining a basic procedure for extracting a bend corner portion. Here, a plurality of target positions P0, P1, P2, P3, and P4 are set in this order along the path PS, and the target position P2 is a bend corner portion of the path PS. There are various methods for automatically detecting this bend corner portion. For example, an angle (θ 1a , θ 1b ) is obtained by connecting at least three target positions, namely, one of the plurality of target positions (e.g., target position P1), a front side target position (target position P2) arranged at the front of the modeling direction along the path PS, and a rear side target position (target position P0) arranged at the rear of the modeling direction, with the target position as _{the center} . This process is performed for each of the plurality of target positions. Then, the position at which the obtained angle is smallest is determined as the bend corner portion.

In other words, at least three target positions are determined: one of the multiple target positions, and among the other target positions included within a predetermined radial distance from the one target position, a front side target position located ahead in the printing direction along the path PS, and a rear side target position located behind the printing direction. The smaller angle formed by connecting these three target positions is determined for all of the multiple target positions, or for a part of a specific area. The bend angle is determined from the result.

Specifically, at the target position P1 described above, the two bend angles θ _1a and θ _1b are both substantially equal obtuse angles, and it cannot be said that the target position P1 is a bend angle portion. Next, at the target position P2, the angle formed by connecting P1, P2, and P3 is the inner bend angle θ _2a and the outer bend angle θ _2b , and the smaller bend angle θ _2a is set as the bend angle value. Next, at the target position P3, the bend angle formed by connecting P2, P3, and P4 is substantially equal obtuse angles as in the case of the target position P1, and it cannot be said that the target position P2 is a bend angle portion. In this way, the bend angles are obtained for all the target positions, and the smallest bend angle among the obtained bend angles is θ _2a , so it can be determined that the bend angle portion is the target position P2.

The arrangement of multiple target positions shown in Figure 4 is a simple pattern that makes it easy to extract bend corners, but the arrangement of target positions in actual additive manufacturing is complex, and it is often difficult to reliably and accurately extract bend corners. Therefore, it is necessary to appropriately arrange the basic steps above to extract bend corners with high precision.

Figure 5 is a schematic diagram of a path to explain another procedure for extracting bend corners. In this procedure, instead of setting one position along the path PS ahead in the modeling direction as the front-side target position in the basic procedure shown in Figure 4, a predetermined number of target positions (e.g., six) ahead in the modeling direction are set as the front-side target positions.

That is, for the target position P1, the smaller bend angle formed by connecting P0-P1-P7 is _θ1 . For the target position P2, the smaller bend angle formed by connecting P1-P2-P8 is _θ2 . Similarly, bend angles _θ3 to _θ5 are set for the target positions P3 to P5. Among these bend angles _θ1 to _θ5 , the smallest bend angle is _θ5 , so the target position P5 is extracted as the bend angle portion. Note that, for the rear target position, a predetermined number of target positions arranged rearward in the modeling direction may be set as the rear target position. In this way, by setting a line connecting the target positions across a plurality of target positions, the influence of the disorder of the arrangement of the target positions can be suppressed, and the extraction accuracy of the bend angle portion can be improved.

6 is a graph showing a distribution of bend angles θ with respect to target positions P _i (i is an integer representing an index). As shown in FIG. 6, even if the calculated bend angle θ has multiple extreme values θ _min1 and θ _min2 , the bend angle portion can be accurately identified by selecting the target position of the smallest value θ _min2 as the bend angle portion.

However, the above method may miss a bend in the corner. In that case, other conditions may be used to identify the bend.
FIG. 7 is a graph showing another distribution of the bend angle θ with respect to the target position P _i . When there is a defect or inconsistency in the target position of the modeling plan, the angle to be the bend angle part may deviate from the original value. In that case, a range W is determined and a target position within the range W where the bend angle θ is the minimum is searched for. The position and size of this range W may be changed, and by searching for the minimum value each time it is changed, even if the minimum value for all the target positions P _i is θ _min2 , other bend angle parts such as θ _min1 can be extracted without being affected by it. Furthermore, the minimum value may be obtained after a smoothing process is performed on the distribution of the bend angle θ, and the bend angle may be determined using other criteria based on a differential value or the like other than the minimum value.

Next, in order to appropriately correct the path at the extracted bend corner, a virtual repulsive force is first applied to target positions near the bend corner (S3). Adjusting the path by applying a virtual repulsive force to each target position can be roughly explained as follows.

If the multiple passes are arranged with equal intervals and not too close to each other, gaps are less likely to occur even at the bend corners shown in FIGS. 16A and 16B, which can contribute to improving the quality of the model.
8A to 8D are explanatory diagrams showing a step-by-step procedure for equalizing the spacing between paths. As shown in Fig. 8A, assume that there are four paths PS1, PS2, PS3, and PS4. The distance between paths PS2 and PS3 is narrower than the distance between paths PS1 and PS2, and the distance between paths PS3 and PS4.

Therefore, as shown in FIG. 8B, elastically expanding and contracting springs Sp1, Sp2, and Sp3 are virtually provided between each of the four paths PS1, PS2, PS3, and PS4. That is, a spring Sp1 is provided between paths PS1 and PS2, a spring Sp2 is provided between paths PS2 and PS3, and a spring Sp3 is provided between paths PS3 and PS4. The spring constants of all springs are the same. Also, as a constraint condition, the positions of the outer paths PS1 and PS4 are fixed so that the shape of the model does not change.

As a result, as shown in FIG. 8C, the elastic repulsive force of spring Sp2 between closely spaced paths PS2 and PS3 pushes path PS2 back toward path PS1, and pushes path PS3 back toward path PS4. As a result, as shown in FIG. 8D, paths PS2 and PS3 move to positions where springs Sp1, Sp2, and Sp3 are mechanically balanced. In this way, paths PS1, PS2, PS3, and PS4 are arranged with uniform intervals between each other.

When beads are formed along the paths PS1 to PS4 obtained as described above, the beads do not get too close to each other locally, and therefore gaps are less likely to form between the beads. In addition, the occurrence of unevenness (narrow parts) on the surface to be molded is suppressed.

The above-mentioned path correction procedure will now be described in more detail.
9A to 9C are schematic explanatory diagrams showing the steps of how adjacent passes are evenly arranged. FIG. 9A shows a pair of passes PSa and PSb adjacent to each other. Each pass PSa and PSb is represented by a line connecting target positions P _i and Q _j (i and j are indexes), which are also the movement target positions of the torch. A virtual repulsive force is applied to each of the target position P _i of the pass PSa and the target position Q _j of the pass PSb. Here, the repulsive force is exemplified by an elastic restoring force by a spring, but is not limited to this. For example, other mechanical models such as Coulomb force, magnetic force, and pressure may be used.

When a spring is used as a source of repulsive force, the spring Sp is disposed between target position P _i and target position Q _j (i, j = 1 to 7) here. That is, it is assumed that a spring is provided between adjacent positions such as between target position P ₁ and target position Q ₁ , between target position P ₂ and target position Q ₂ , etc. The spring Sp generates a repulsive force according to the distance between path PSa and path PSb, specifically, the distance between target position P _i and target position Q _j on the path.

9B, when a repulsive force acts on the target positions P _i and Q _j , the paths PSa and PSb move away from each other. This repulsive force decreases as the spring stretches with the movement of the paths PSa and PSb and approaches a mechanical equilibrium state.

Figure 10 is a graph showing a schematic change in the path movement distance over time. Paths PSa and PSb move due to a repulsive force. The movement distance converges to a certain distance Lc. As a result, as shown in Figure 9C, paths PSa and PSb stop moving at a position where they are in an equilibrium state. This position becomes the placement position of the equalized paths. More specifically, the movement of the target position is suppressed by a damping force that reduces the path movement speed, and an equilibrium state is achieved.

The above-mentioned mathematical model of the repulsive force can be exemplified by the following formulas (1) to (3): When the target position on the path PSa is P _i and the target position on the path PSb is Q _j , the repulsive force F _i acting on the i-th target position can be calculated by the formulas (1) to (3).

Here, k is a constant, x _i is the coordinate of the target position P _i in the path PSa, and x _j is the coordinate of the target position Q _j in the path PSb. The coordinates shown here are uniaxial coordinates, but may be two-dimensional planar coordinates or three-dimensional spatial coordinates. Also, S ₀ is the limit distance (influence radius described later) at which the repulsive force F is affected, and when the distance between the target positions is S ₀ or more, it is considered that the repulsive force F has no effect from the distant position. In other words, the repulsive force F _i acting on the i-th target position P _i is the sum of the elastic forces from the spring Sp between the target position Q _j and the target position P _i in an area closer than the distance S ₀ .

FIG. 11 is a schematic explanatory diagram when the above mathematical model is applied to each pass PS1 to PS3. The repulsive force F acting on the target position Pa of the intermediate pass PS2 is calculated based on the above formulas (1) to (3). That is, when the distance between the target position Pa and other target positions is considered in two dimensions, the target positions Pa ₁ and Pa ₂ other than the target position Pa that exist within the range AR1 of the radius (influence radius) R1 centered on the target position Pa are extracted, and each repulsive force according to the distance between the target position Pa and the target position Pa ₁ and the distance between the target position Pa and the target position Pa ₂ is generated at the target position Pa. In this way, it is preferable to apply the repulsive force only to the target positions Pa ₁ and Pa ₂ and to limit the range in which the repulsive force is generated. In that case, the calculation for analysis can be performed in a simpler system.

The repulsive force F to be applied may be differentiated between within the same path and between different paths. In other words, the influence radii R1 and R2 are divided for springs generated between the same path and between different paths, and separate springs are generated for each. This makes it possible to limit the generation of unintended springs and repulsive forces. The spring constants of the generated springs can also be differentiated, with k1 for within the same path and k2 for between different paths. Note that it is preferable to increase the repulsive force between each target position as the bend angle becomes smaller (however, the dependence of the bend angle θ is limited to the spring constant k1 within the same path).

Specifically, a repulsive force is generated at the target position Pa according to the distance between the target positions Pa3 and Pa4 of other passes that exist within a range AR2 of influence radius R2 centered on the target position Pa. This allows the distance between the target positions to be adjusted more appropriately.

Fig. 12 is an explanatory diagram showing a state where a repulsive force is applied between the target positions of the path PS _out at the bend corner portion shown in Fig. 4 and the path PS _in inside the bend corner portion shown in Fig. 5. Taking the target position P _{in_c} of the path PS _in as an example, target positions P _{in_1} and P _{in_2} other than the target position P _{in_c that exist within a range AR1 from the target position P in_c to} an influence radius R1 are extracted, and springs are generated between the target positions P _{in_c} and P _{in_1} , and between the target positions P _{in_c} and P _{in_2} , respectively. Also, target positions P _{out_1} and P _{out_2} other than the path PSin that exist within a range AR2 from the target position P _{in_c} to an influence radius R2 are extracted, and springs are generated between the target positions P _{in_c} and P _{out_1} , and between the target positions P _{in_c} and P _{out_2} , respectively.

In this case too, the spring constant of the springs in the same path is k1, and the spring constant of the springs between different paths is k2 (k2 ≠ k1).

Furthermore, a force that converges the movement of the target position caused by the repulsive force (attenuates the movement speed) may be assumed. This force is proportional to the movement speed of the target position when the repulsive force acts on each target position on the path.

Here, vector u is the velocity vector of each target position, vector x is the position vector of each target position, t is time, Δt is the amount of change over time, vector F is the repulsive force matrix, and c is the damping coefficient. For details of the above calculations, please refer to JP 2015-230530 A as appropriate.

The term of the damping coefficient c in equation (4) is a term that dampens the moving speed of the target position due to the repulsive force F, and stops the movement of paths PSa and PSb in FIG. 9C. This causes the amount of change in the position to converge over time. This convergence of the amount of change may be, for example, by ceasing to update the amount of movement when the amount of movement of the target position falls below a predetermined value. The calculation of the amount of movement may also be repeated multiple times. In this case, multiple candidates for correction positions that eliminate closely packed paths can be extracted.

Furthermore, the bend angle calculation unit 33 may add other target positions that are located on the path to the multiple target positions acquired by the target position information acquisition unit 31. In this case, it is expected that the information on the added target positions will make it easier to extract the bend angle portion, enabling more accurate extraction.

As mentioned above, the positions of the paths that form the contour of a layer are fixed. By allowing the positions of only the paths that are placed within the contour to be movable, paths can be evenly placed within the contour without changing the shape of the contour.

As described above, by applying a repulsive force to adjacent target positions among the multiple target positions, the movement amount by which the target positions move from the position before the repulsive force is applied to the position where the target positions are mechanically balanced after the repulsive force is applied is analytically calculated for the multiple target positions (S4). This process is performed by the target movement amount calculation unit 41 shown in FIG. 2.

Next, the modeling path correction unit 37 corrects the position of the path in accordance with the calculated movement amount (S5).
FIG. 13 is an explanatory diagram showing the result of changing the position of the path. In FIG. 12, the target position P _{out_c} of the path PS _out and the target position P _{in_c} of the path PS _in are separated at the bend corner portion of the path PS _out , and a relatively wide gap is generated. However, by correcting the path by applying the above-mentioned repulsive force, the target positions of the path PS _out and the path PS _out are left as they are, and a plurality of target positions including the target position P _{in_c} of the path PS _in are moved. As a result, the gap between the target position P _{out_c} and the target position P _{in_c} is narrowed, and the interval between the target positions of the path PS _in is widened. The interval between the target positions of the path PS _in is made larger as the bend angle of the bend corner portion is smaller. In this way, the modeling path correction unit 37 optimizes the path at the bend corner portion so that defects due to gaps are less likely to occur. According to the optimized path, the height of the formed bead is approximately uniform at the bend corner portion and at the portion other than the bend corner portion, and the occurrence of steps can be suppressed.

Then, the control information generating unit 39 generates control information including information of the corrected path. When this control information is output to the molding control unit 13 shown in Fig. 1, the molding control unit 13 changes the molding plan to paths PS _in and PS _out shown in Fig. 13. As a result, when the control information generated by the control information generating device 200 is sent to the molding control unit 13, the molding control unit 13 controls the molding unit 11 to perform arc welding along the corrected path, so that additive manufacturing of a high-quality object with reduced defects is possible.

<Example of optimization of paths for each filling part of folds>
Next, the results of optimizing the path of the created molding plan according to the above-mentioned procedure will be described.
Fig. 14A is an explanatory diagram showing paths according to a modeling plan when filling the inside of a rectangle with beads, and Fig. 14B is an explanatory diagram showing the result of optimizing the paths in Fig. 14A. In the path before optimization, gaps are likely to occur between beads at bend corners (corners). On the other hand, in the path after optimization, the distance between the bend corners and the surrounding paths is shortened, making it less likely that gaps will occur.

Figure 15A is an explanatory diagram showing a path according to a modeling plan when filling the inside of a rectangle with a circular hole with a bead, and Figure 15B is an explanatory diagram showing the result of optimizing the path of Figure 15A. In this case, too, the distance between the optimized path and the surrounding paths is shortened, even at sharp bends, making it less likely for gaps to occur.

In this way, by automatically extracting bend corners and correcting paths near the bend corners, it is possible to efficiently create a modeling plan that is close to the ideal, without the need for manual work or experience.

The present invention is not limited to the above-described embodiments, and it is intended that the various configurations of the embodiments be combined with each other, and that those skilled in the art may modify and apply the invention based on the description in the specification and well-known techniques, and this is included in the scope of the protection sought.

As described above, the present specification discloses the following:
(1) A control information generation device that generates control information for controlling an additive manufacturing device that forms a layer shape using a bead formed by adding a molten processing material to a processing target surface while moving a processing position along a modeling path, and laminates the layer shapes to model a three-dimensional shape of a desired object, the control information generation device comprising:
a target position information acquisition unit that acquires information on a plurality of target positions for bead formation in the molding path;
a bend angle calculation unit that extracts bend angle portions of the modeling path from the plurality of target positions and calculates bend angles of the extracted bend angle portions;
a target position interval correction unit that corrects intervals between the target positions arranged in an inner region between the modeling paths of the bending corner portion;
a modeling path correction unit that corrects the modeling path so that the interval between the target positions is increased as the bend angle of the bend angle portion is smaller;
a control information generating unit that generates the control information including information of the corrected modeling path;
A control information generating device comprising:
According to this control information generating device, the bend angle calculation unit extracts a bend angle portion from the information on the target position acquired by the target position information acquisition unit, and the target position interval correction unit corrects the modeling path so that the interval between the target positions located in the inner area of the bend angle is increased as the bend angle becomes smaller, and the control information generating unit generates control information including the corrected modeling path. As a result, even if a bend angle portion occurs, the modeling path can be corrected to one that is less likely to cause defects such as unwelded beads between beads. In addition, the control information can be used to control the additive manufacturing device to stack high-quality objects.

(2) The control information generation device described in (1), wherein the bend angle calculation unit determines the bend angle from a result of calculating a smaller angle formed by connecting at least three target positions, the smaller angle being one of the plurality of target positions and at least three other target positions included within a predetermined radial distance from the one target position as a center, the smaller angle being a front-side target position located ahead in the printing direction along the printing path and a rear-side target position located behind the printing direction, for all or some of the plurality of target positions.
According to this control information generating device, the bend angle is determined from the angle determined by connecting three target positions, so even if the tip of the bend angle portion is chipped or part of the target position is positioned away in an unintended direction, an appropriate bend angle can be mechanically calculated.

(3) The control information generating device according to (2), wherein the bend angle is determined to be a minimum angle, or a minimum angle within a predetermined range, from among the calculated angles.
According to this control information generating device, by setting the minimum angle as the bend angle, it is possible to easily identify the bend angle location.

(4) A movement amount calculation unit is further provided that virtually applies a repulsive force between the plurality of target positions and estimates a movement amount of the target position from a dynamic balance position of the applied repulsive force,
The control information generating device according to any one of (1) to (3), wherein the modeling path correction unit adds the estimated movement amount to an interval between the target positions.
According to this control information generating device, when a repulsive force is applied between target positions, the target positions move to a position where they are mechanically balanced, utilizing the mechanical behavior, and the distance between the target positions can be analytically calculated.

(5) The repulsive force is
A repulsive force within the same path acting between adjacent target positions in the same modeling path;
A repulsive force between adjacent paths acting between the target position of the modeling path and the target position of another modeling path adjacent to the modeling path;
The control information generating device according to (4).
According to this control information generating device, the target positions of the bend corner portions of each modeling path can be adjusted to appropriate positions by equalizing the distance between target positions within the same path and also equalizing the distance between target positions between adjacent paths.

(6) The control information generation device according to (4) or (5), wherein the repulsive force is generated between any one of the target positions and another of the target positions that is included within a prescribed influence radius centered on the target position.
According to this control information generating device, by limiting the range in which the repulsive force occurs, calculations for analysis can be performed with a simpler system.

(7) The control information generating device according to any one of (1) to (6), wherein the bend angle calculation unit extracts the bend angle portion from information obtained by adding other target positions to be placed on the modeling path to the plurality of target positions acquired by the target position information acquisition unit.
According to this control information generating device, by increasing the number of target positions, the bend angle can be obtained with higher accuracy.

(8) A control information generation method for controlling an additive manufacturing device that forms a layer shape by adding a molten processing material to a processing target surface while moving a processing position along a modeling path, and stacks the layer shapes to form a three-dimensional shape of a desired object, comprising:
Acquire information on a plurality of target positions for bead formation in the molding path;
Extracting bend corner portions of the shaping path from the plurality of target positions, and determining bend angles of the extracted bend corner portions;
Correcting intervals between the target positions arranged in an inner region of the bending corner portion sandwiched between the modeling paths;
The modeling path is modified so that the interval between the target positions is increased as the bend angle of the bend angle portion is smaller;
generating the control information including information of the modified modeling path;
A method for generating control information.
According to this control information generating method, a bend angle portion is extracted from the acquired target position information, the modeling path is modified so that the distance between the target positions located in the inner area of the bend angle is increased as the bend angle becomes smaller, and control information including the modified modeling path is generated. As a result, even if a bend angle portion occurs, the modeling path can be modified to one that is less likely to cause defects such as non-welding between beads. In addition, the control information can be used to control the additive manufacturing device to laminate a high-quality model.

(9) A program for executing a procedure of a control information generating method for generating control information for controlling an additive manufacturing device that forms a layer shape by using a bead formed by adding a molten processing material to a processing target surface while moving a processing position along a modeling path, and laminates the layer shapes to model a three-dimensional shape of a desired object, the program comprising:
On the computer,
acquiring information on a plurality of target positions for bead formation in the modeling path;
A step of extracting bend corner portions of the shaping path from the plurality of target positions and determining bend angles of the extracted bend corner portions;
correcting intervals between the target positions arranged in an inner region of the bending corner portion sandwiched between the modeling paths;
a step of correcting the modeling path so that the interval between the target positions is increased as the bend angle of the bend angle portion is smaller;
generating the control information including information of the modified modeling path;
A program that executes the following.
According to this program, the program extracts bend corners from the acquired target position information, modifies the modeling path so that the distance between the target positions located in the inner area of the bend corners is increased as the bend angle becomes smaller, and generates control information including the modified modeling path. As a result, even if a bend corner occurs, the modeling path can be modified to one that is less likely to cause defects such as unwelded beads between beads. In addition, the program can control the additive manufacturing device to laminate a high-quality model using this control information.

(10) A control information generating device according to any one of (1) to (7),
the additive manufacturing apparatus performing arc welding along the manufacturing path based on the control information generated by the control information generating device;
A welding device comprising:
This welding device makes it possible to perform additive manufacturing of objects while minimizing the occurrence of defects.

(11) A welding method for performing arc welding along the shaping path based on control information generated by the control information generation method according to (8).
This welding method makes it possible to perform additive manufacturing of objects while suppressing the occurrence of defects.

11 Modeling unit 13 Modeling control unit 17 Manipulator 19 Filler material supply unit 19a Reel 19b Payout mechanism 21 Manipulator control unit 23 Heat source control unit 25 Torch 27 Base 31 Target position information acquisition unit 33 Bend angle calculation unit 35 Target position interval correction unit 37 Modeling path correction unit 39 Control information generation unit 41 Movement amount calculation unit 100 Layered modeling device 200 Control information generation device AR1, AR2 Range B Bead F Repulsive force M Filler material P0, P1, P2, P3, P4, P5, Pa, Pa ₁ , Pa ₂ , Pa ₃ , Pa ₄ , P _{in_1} , P _{in_2} , P _{in_c} , P _{out_1} , P _{out_2,} P _{out_c} , P _i (i = 1 to 7), Q _j (j = 1 to 7) Target position PS, PS1, PS2, PS3, PS4, PSa, PSb, PS _in , PS _out Path (printing path)
R1, R2: radius of influence W: range Wk: object θ, θ _1a , θ _1b , θ _2a , θ _2b , θ ₃ , θ ₄ , θ _5: bending angle

Claims (11)

A control information generating device that generates control information for controlling an additive manufacturing device that forms a layer shape using a bead formed by adding a molten processing material to a processing target surface while moving a processing position along a modeling path, and laminates the layer shapes to form a three-dimensional shape of a desired object, comprising:
a target position information acquisition unit that acquires information on a plurality of target positions for bead formation in the molding path;
a bend angle calculation unit that extracts bend angle portions of the modeling path from the plurality of target positions and calculates bend angles of the extracted bend angle portions;
a target position interval correction unit that corrects intervals between the target positions arranged in an inner region between the modeling paths of the bending corner portion;
a modeling path correction unit that corrects the modeling path so that an interval between the target positions is increased as the bend angle of the bend angle portion is smaller; and
a control information generating unit that generates the control information including information of the corrected modeling path;
A control information generating device comprising: The bend angle calculation unit determines the bend angle from a result of calculating a smaller angle formed by connecting at least three target positions, the smaller angle being one of the plurality of target positions, a front-side target position disposed ahead in the printing direction along the printing path, and a rear-side target position disposed behind the printing direction, among the other target positions included inside a predetermined radial distance around the one target position, for all or a part of the plurality of target positions.
The control information generating device according to claim 1 . Among the angles thus obtained, a minimum angle or a minimum angle within a predetermined range is determined as the bend angle.
The control information generating device according to claim 2 . a movement amount calculation unit that virtually applies a repulsive force between the plurality of target positions and estimates a movement amount of the target position from a dynamic balance position of the applied repulsive force,
The modeling path correction unit adds the estimated movement amount to an interval between the target positions.
The control information generating device according to claim 1 . The repulsive force is
A repulsive force within the same path acting between adjacent target positions in the same modeling path;
A repulsive force between adjacent paths acting between the target position of the modeling path and the target position of another modeling path adjacent to the modeling path;
The control information generating device according to claim 4 , further comprising: The repulsive force is generated between any one of the target positions and another of the target positions included within a specified radius of influence centered on the target position.
The control information generating device according to claim 4. The bend angle calculation unit extracts the bend angle portion from information obtained by adding other target positions to be arranged on the modeling path to the plurality of target positions acquired by the target position information acquisition unit.
The control information generating device according to claim 1 . A control information generation method for generating control information for controlling an additive manufacturing device that forms a layer shape using a bead formed by adding a molten processing material to a processing target surface while moving a processing position along a modeling path, and laminates the layer shapes to form a three-dimensional shape of a desired object, comprising:
Acquire information on a plurality of target positions for bead formation in the molding path;
Extracting bend corner portions of the shaping path from the plurality of target positions, and determining bend angles of the extracted bend corner portions;
Correcting intervals between the target positions arranged in an inner region of the bending corner portion sandwiched between the modeling paths;
The modeling path is modified so that the interval between the target positions is increased as the bend angle of the bend angle portion is smaller;
generating the control information including information of the modified modeling path;
A method for generating control information. A program for executing the steps of a control information generation method for generating control information for controlling an additive manufacturing device that forms a layer shape using a bead formed by adding a molten processing material to a processing target surface while moving a processing position along a modeling path, and laminates the layer shapes to form a three-dimensional shape of a desired object, the program comprising:
On the computer,
acquiring information on a plurality of target positions for bead formation in the modeling path;
A step of extracting bend corner portions of the shaping path from the plurality of target positions and determining bend angles of the extracted bend corner portions;
correcting intervals between the target positions arranged in an inner region of the bending corner portion sandwiched between the modeling paths;
a step of correcting the modeling path so that the interval between the target positions is increased as the bend angle of the bend angle portion is smaller;
generating the control information including information of the modified modeling path;
A program that executes the following. A control information generating device according to any one of claims 1 to 3,
the additive manufacturing apparatus performing arc welding along the manufacturing path based on the control information generated by the control information generating device;
A welding device comprising: A welding method for performing arc welding along the forming path based on control information generated by the control information generation method described in claim 8.

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