Molding condition setting device, laminate molding system, molding condition setting method, and program

Abstract

To provide a technique for performing laminate molding by appropriately controlling the angle of a torch in accordance with the shape of a molded object while keeping an ideal distance between the torch and the molded object.SOLUTION: This molding condition setting device is for setting a molding condition when laminate-molding an object to be molded by a WAAM method, and comprises: means for determining whether a difference between a measurement value of a distance between a torch and a molded object and a design value of the distance is within a permissible range; and means for correcting, when the difference exceeds the permissible range, a target welding position included in the molding condition so as to set the difference within the permissible range, and correcting a torch angle so as to match a molding direction on the basis of the shape of the object to be molded at the corrected target welding position.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a modeling condition setting device, an additive manufacturing system, a modeling condition setting method, and a program. [Background technology]

[0002] Wire Arc Additive Manufacturing (WAAM) is a popular additive manufacturing method that builds desired shapes by layering weld beads made by melting and solidifying filler metal. To create high-precision objects, the width and height of the weld beads must be controlled. However, in actual manufacturing, the desired shape of the weld bead may not be achieved. For example, if the temperature of the object rises excessively during printing, the weld bead flattens, widening the width and reducing the height, as shown in Figure 8A. Especially when the number of layers is large, height errors have an integral effect. Therefore, even slight differences per layer can become significant as the number of layers increases. In addition to changes in shape, this can lead to changes in the distance between the torch and the object, resulting in unstable printing or even contact between the torch and the object. To address this issue, Patent Document 1 discloses a method for measuring the shape of an existing weld bead using a sensor attached to a torch, adjusting welding conditions such as the amount of filler metal supplied, welding speed, heat input, and weaving conditions to reduce the difference between the measured weld bead height and the planned value, and then performing subsequent additive manufacturing. However, changing the welding conditions can change the build width. This can undesirably result in a thin-walled object where each layer is built in one pass (one welding) during additive manufacturing, resulting in an object with a different thickness than the planned object.

[0003] If the shape of the weld bead becomes flattened due to an excessive temperature rise during printing, even if the difference per layer is small, as the number of layers increases, the integral of that difference changes the distance between the torch and the printed object, and this difference cannot be ignored, resulting in an increase in the distance between the torch and the printed object. Figure 8B shows the relationship between the distance between the torch and the printed object and quality. Figure 81 on the left side of Figure 8B shows the ideal distance between the torch and the printed object. Figure 82 in the center of Figure 8B shows the state when the distance between the torch and the printed object is farther. This can result in defects and an unstable arc. Figure 83 on the right side of Figure 8B shows the state when the distance between the torch and the printed object is closer. This can result in interference between the object and the torch and unstable printing. If the weld bead becomes flat, the torch and the object will separate, which can lead to unstable welding. Furthermore, for objects where the build angle changes, if the shape of the weld bead becomes flat, errors in the build height per layer accumulate during multilayer builds. Furthermore, because the angle change corresponding to the arc length is not reflected, the resulting shape is completely different from the planned build. An example of such builds is shown in Figure 8C. Line 84 in Figure 8C shows the trajectory of the build (the path of the torch tip) set to reflect the shape of the object to be built, and line 85 shows the shape of the actual build. In this example, the build height error per layer accumulates due to the effects of flattening and changes in the distance between the torch and the object, and the resulting inability to appropriately change the torch angle, resulting in a shape different from the target. To perform additive manufacturing without changing the shape of the object, it is necessary to maintain the ideal distance between the torch and the object while simultaneously changing the torch angle according to the desired shape, without changing the welding conditions that would change the build width. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6912636 Summary of the Invention [Problem to be solved by the invention]

[0005] To provide a technology for layered manufacturing that appropriately controls the torch angle according to the shape of the object while maintaining an ideal distance between the torch and the object.

[0006] The present disclosure provides a modeling condition setting device, an additive manufacturing system, a modeling condition setting method, and a program that can solve the above-mentioned problems. [Means for solving the problem]

[0007] The manufacturing condition setting device according to the present disclosure is a manufacturing condition setting device that sets manufacturing conditions when additive manufacturing an object to be manufactured using the WAAM method, and includes a means for determining whether the difference between the measured value of the distance between the torch and the object to be manufactured and the design value of the distance is within an acceptable range, and, if the difference exceeds the acceptable range, a means for correcting a target welding position included in the manufacturing conditions so that the difference falls within the acceptable range, and a means for correcting a torch angle so that it matches the manufacturing direction based on the shape of the object to be manufactured at the corrected target welding position.

[0008] The additive manufacturing system according to the present disclosure is an additive manufacturing system that additively manufactures an object to be manufactured using the WAAM method, and includes a welding system having a torch and a sensor that measures the distance to an object fixed in a fixed positional relationship with the torch, a control device that controls the welding system, and the above-mentioned manufacturing condition setting device.

[0009] The manufacturing condition setting method according to the present disclosure is a computer-executed method for setting manufacturing conditions when additive manufacturing an object to be manufactured using the WAAM method, and includes the steps of: determining whether a difference between a measured value of the distance between the torch and the object to be manufactured and a design value of the distance is within an acceptable range; and, if the difference exceeds the acceptable range, correcting a target welding position included in the manufacturing conditions so that the difference falls within the acceptable range; and correcting a torch angle so that it matches the manufacturing direction based on the shape of the object to be manufactured at the corrected target welding position.

[0010] The program according to the present disclosure causes a computer to execute a process for setting the manufacturing conditions when additively manufacturing an object to be manufactured using the WAAM method, the process including the steps of determining whether the difference between the measured value of the distance between the torch and the object to be manufactured is within an acceptable range and, if the difference exceeds the acceptable range, correcting the target welding position included in the manufacturing conditions so that the difference falls within the acceptable range, and correcting the torch angle so that it matches the manufacturing direction based on the shape of the object to be manufactured at the corrected target welding position. [Effects of the Invention]

[0011] The manufacturing condition setting device, additive manufacturing system, manufacturing condition setting method, and program disclosed herein enable additive manufacturing while maintaining an ideal distance between the torch and the object to be manufactured, and controlling the torch angle to an appropriate angle according to the shape of the object. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a block diagram illustrating an example of an additive manufacturing system according to an embodiment. [Figure 2] 5A and 5B are diagrams illustrating the positional relationship between a torch and a sensor and a model according to an embodiment. [Figure 3] FIG. 1 is a first diagram illustrating a distance measurement method according to an embodiment. [Figure 4] FIG. 2 is a second diagram illustrating the distance measurement method according to the embodiment. [Figure 5] 10A to 10C are first diagrams illustrating a method for correcting a modeling path according to an embodiment. [Figure 6] 10A and 10B are second diagrams illustrating the method for correcting a modeling path according to the embodiment. [Figure 7] 10 is a flowchart illustrating an example of a forming condition setting process according to the embodiment. [Figure 8A] FIG. 1 is a first diagram showing an example of a problem that occurs during additive manufacturing. [Figure 8B] FIG. 2 is a second diagram showing an example of a problem that occurs during additive manufacturing. [Figure 8C] FIG. 3 is a third diagram showing an example of a problem that occurs during additive manufacturing. [Figure 9] FIG. 2 illustrates an example of a hardware configuration of a control device according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] <Embodiment> Hereinafter, the method for detecting and correcting a modeling path in the WAAM-based additive manufacturing of the present disclosure will be described with reference to the drawings. (composition) FIG. 1 is a block diagram illustrating an example of an additive manufacturing system according to an embodiment. The additive manufacturing system 100 includes a welding system 1 and a control device 10. The welding system 1 includes a welding robot 2, a welding machine 3, a wire feeder 4, a torch 5, a sensor 8, a cooling device 9, etc. The torch 5 is equipped with a sensor 8 for non-contact measurement of the distance between the torch 5 and the object 6. The sensor 8 is, for example, a laser rangefinder, but is not limited to this. For example, the sensor 8 may be a sensor that measures distance using ultrasound or an image. The sensor 8 is fixed at a position where it measures the distance between the sensor 8 and the object 6 at a position preceding the object being manufactured by the torch 5. The cooling device 9 is a device that sprays water or air onto the object 6. The cooling device 9 is used to forcibly cool the object 6 when its temperature rises excessively. The welding system 1 performs additive manufacturing using the WAAM method based on instructions from the control device 10, and manufactures the object 6 on the positioning device 7. The welding system 1 performs the manufacturing process using short-circuit transfer MIG welding. Short-circuit transfer MIG welding is characterized by low heat input (low molten pool temperature) and high viscosity of the weld bead. By using short-circuit transfer MIG welding, deformation of the weld bead due to gravity can be ignored even when manufacturing is performed with the torch 5 facing not only vertically downward but also diagonally or sideways (horizontally), and the desired shape can be manufactured in the same way as when manufacturing is performed in a downward direction. The control device 10 includes a shape data acquisition unit 11, a distance detection unit 12, a manufacturing condition setting unit 13, a control unit 14, and a memory unit 15.

[0014] The shape data acquisition unit 11 acquires shape data of the object to be formed. The shape data is, for example, a three-dimensional model (CAD data) that represents the shape of the object to be formed. From the shape data, the width, size, etc. of the object to be formed at any position can be calculated. The distance detection unit 12 detects the distance between the tip of the torch 5 and the surface of the object 6. Specifically, the distance detection unit 12 acquires the value measured by the sensor 8, and detects the distance from the tip of the torch 5 to the object 6 based on this value.

[0015] The printing condition setting unit 13 sets various printing conditions required for printing the object 6. For example, the printing condition setting unit 13 initially sets a printing path for each layer of the object 6. The printing path includes a printing center position and a torch angle that represent the target welding position for each layer. The printing condition setting unit 13 sets various welding conditions such as a welding speed, voltage, current, wire supply amount, and torch angle. For example, the printing condition setting unit 13 sets the torch angle in a direction that matches the printing direction of the object corresponding to the position of the torch 5. When printing actually starts, the printing condition setting unit 13 corrects the printing path. For example, the printing condition setting unit 13 calculates the difference between the initially set printing center position and the actual position where printing was performed based on the distance detected by the distance detection unit 12, and corrects the printing center position so that the distance detected by the distance detection unit 12 becomes a predetermined distance. When the printing center position is corrected, the printing condition setting unit 13 corrects the torch angle in a direction along the shape of the object 6 at the corrected printing center position (tangential direction of the object 6). Furthermore, when the printing condition setting unit 13 determines that there is a possibility that the temperature of the object 6 has risen excessively based on the magnitude of the difference between the distance detected by the distance detection unit 12 and the ideal distance, it determines that the printing condition of the object 6 is to cool the object 6.

[0016] The control unit 14 controls the welding system 1 based on the building path and welding conditions set by the building condition setting unit 13, and performs WAAM-type additive manufacturing using short-circuit transfer MIG welding. For example, the control unit 14 performs building based on the building path corrected by the building condition setting unit 13, adjusting the position and angle of the torch 5 so that the distance between the torch 5 and the object 6 is not too close or too far, but is within a predetermined tolerance range, and so that the torch angle does not deviate from the tangent direction of the shape of the object at the building position. In addition, when the weld bead is flattened due to an excessive temperature rise of the object 6, the control unit 14 operates the cooler 9 to cool the object 6 and suppress changes in the shape of the object 6. The storage unit 15 stores the shape data acquired by the shape data acquisition unit 11, the modeling path and welding conditions set by the modeling condition setting unit 13, a database (described later) used to calculate the welding conditions, and the like.

[0017] Next, a method for detecting the distance between the torch 5 and the object 6 will be described with reference to FIG. 2. As shown in FIG. 2, the sensor 8 is fixed at a position in the traveling direction of the torch 5 where the distance between the reference surface 8a of the sensor 8 and the reference surface 5a of the torch 5 is a predetermined value Df. The sensor 8 measures the distance Lb to the object 6. The position of the object 6 to be measured is the surface of the layer one layer below the layer currently being formed. Then, the distance Rf between the torch 5 and the object 6 can be calculated by Rf = Lb - Df. The distance detection unit 12 may detect the distance Rf between the torch 5 and the object 6 by subtracting Df from the value Lb measured by the sensor 8, or may treat the measured value Lb as the distance between the torch 5 and the object 6 directly. In this embodiment, from the viewpoint of maintaining a constant distance between the welding object and torch 5 in order to stabilize the quality of welding, sensor 8 is provided ahead of (on the leading side of) the traveling direction of torch 5 so that the distance to the welding object can be measured, but the position is not limited to the example shown in Fig. 2. For example, sensor 8 may be provided on the opposite side of the traveling direction of torch 5, and the distance between torch 5 and object 6 may be detected by adding, for example, an estimated value of the thickness of the layer currently being formed to the value measured by sensor 8.

[0018] A schematic diagram of the cross section of the object 6 is shown in Figure 3. When the torch 5 is facing downward, as shown in Printing Example 31, the distance between the sensor 8 and the apex 61 of the bead of the object 6 is measured vertically. When using MIG welding with short-circuit transfer, the bead can be layered in the direction of the torch angle. Therefore, when the object 6 is inclined (Printing Example 32) or has a shape that extends horizontally (Printing Example 33), the torch 5 is tilted at the same angle as the inclination of the object 6 (when the object is horizontal, the torch 5 is laid horizontally). Even in these cases, the sensor 8 is tilted in the same way as the torch 5, so the distance between the bead apex 61 and the sensor 8 can be measured regardless of the orientation of the torch 5.

[0019] Furthermore, when printing an arc-shaped path as illustrated in FIG. 4, the position of the sensor 8, which measures the distance to the preceding position, may be misaligned horizontally from the position of the torch 5. As a result, the value measured by the sensor 8 may not necessarily represent the distance to the object 6. In such a case, for example, the peak height value (the value at which the distance between the sensor 8 and the object 6 is shortest) among the values ​​measured by the sensor 8 is adopted as the distance Lb (when the sensor 8 measures the distance at each position in the range indicated by the arrow 8b). Even when the printing path is straight, some fluctuations may occur. Therefore, a dead zone may be set for the values ​​measured by the sensor 8 so that some fluctuations can be ignored. Furthermore, regardless of the shape of the printing path, the average or median value of the values ​​measured by the sensor 8 at a predetermined time (in the case of the above-mentioned arc-shaped path, the average value of the adopted peak values, etc.) may be adopted as the distance Lb. Furthermore, if the printing path is a circumference, when printing of the Nth layer starts, goes around the circle, and approaches the original printing start position, the sensor 8 suddenly changes from measuring the distance to the printing surface of the (N-1)th layer to measuring the distance to the Nth layer after printing. If the distance changes suddenly in this way by more than a certain amount, the movement speed of the torch 5 may be controlled to decelerate and the torch position may be controlled to gradually move forward and upward in a slope. This enables stable printing.

[0020] Next, a method for correcting a printing path will be described with reference to FIG. 5. Printing Example 51 in FIG. 5 is a printing example in which beads are stacked vertically. Each arc in Printing Example 51 represents the bead shape of the Nth layer, and the first to fifth layers are illustrated from the bottom up. P1 is the printing center position of the first layer, and P2 to P5 are the printing center positions of the second to fifth layers, respectively. The printing condition setting unit 13 initializes the printing path before actual printing. For example, the positions of P1 to P5 in FIG. 5 are designed. The torch angle at P1 to P5 is designed to match the printing direction, i.e., downward. The control unit 14 moves the torch 5 in accordance with the designed printing path to perform additive printing. Here, a method for initially setting the printing path will be described, focusing on the height positions of P1 to P5. The printing condition setting unit 13 refers to the shape data of the object to be printed in Printing Example 51 and identifies the part of the object to be printed that corresponds to the first layer. The building condition setting unit 13 calculates the width of the identified portion from the shape data, and sets this value as the building width of the first layer. Next, the building condition setting unit 13 references a database that defines the correspondence between building widths and welding conditions, and sets the welding conditions for the first layer. Next, the building condition setting unit 13 references a database that defines the correspondence between building heights and welding conditions, and calculates the building height of the first layer when building is performed under the welding conditions that correspond to the building width of the first layer. The building condition setting unit 13 sets the calculated building height as the height-direction position of P1. Once the building height of the first layer has been calculated, the building condition setting unit 13 references the shape data, identifies the width of the object to be built that corresponds to the building height of the first layer, and sets this value as the building width of the second layer. Then, the building condition setting unit 13 calculates the welding conditions and the building height of the second layer in the same procedure as for the first layer, and sets the value obtained by adding the building height of the first layer to the building height of the second layer as the height-direction position of P2. If the build width of each layer remains constant, the build height of each layer will also be constant. By repeating the same process, the build center positions P3 to P5 of each layer can be set. Furthermore, the build condition setting unit 13 calculates the inclination angle of the object 6 at the build center positions P3 to P5 by referring to the shape data, and sets the torch angle so that the inclination of the torch 5 matches the calculated inclination angle and the tip of the torch 5 faces the lower layer in the build direction. In this example, the torch angle is set vertically downward.The control unit 14 moves the torch 5 to a position where the thus set P1 to P5 corresponds to the center position of the weld (the bead top 61 in Figure 3), and controls the torch angle at each position to be the torch angle set by the weld condition setting unit 13, thereby performing short-circuit transfer MIG welding.

[0021] Here, the vertical movement amount of the torch 5 per layer is Ds, the actual build height per layer is Da, and the fluctuation error is ΔD = Ds - Da. If the first layer can be built as planned, ΔD = 0, and the distance Lb measured by the sensor 8 will be constant. Now, let's assume that due to bead flattening, the actual build height Da of the first layer is smaller than the planned value Ds. Then, if the torch 5 is moved (raised) as planned to build the second layer, the distance between the torch 5 and the object 6 will be ΔD greater than the ideal specified distance Ls. If the distance between the torch 5 and the object 6 increases, the build may become unstable depending on the size of ΔD. Therefore, for example, when the printing condition setting unit 13 detects that the distance Lb measured by the sensor 8 after the start of printing of the second layer is longer by ΔD than the distance Ls (for example, Ls is the ideal distance between the torch 5 and the object 6), the printing condition setting unit 13 corrects the value of the printing center position P2 of the second layer downward by ΔD. Accordingly, the printing condition setting unit 13 also corrects the height directions of P3 to P5 of the third and subsequent layers to lower positions. Correction example 52 in FIG. 5 shows such processing. P2' to P5' are the corrected printing center positions. When the value of the printing center position P2 of the second layer is corrected downward by ΔD, the control unit 14 corrects the position of the torch 5 downward accordingly. As a result, the distance Lb between the torch 5 and the object 6 can be made closer to the distance Ls. For example, the printing condition setting unit 13 calculates the difference ΔL between the distance Lb and the distance Ls (ΔL = Lb - Ls). If ΔL > L1 (the sensor 8 is far from the object 6), the printing condition setting unit 13 corrects the printing center positions P2' to P5' of each layer downward along the printing direction. If ΔL < -L1 (the sensor 8 is close to the object 6), the printing condition setting unit 13 corrects the printing center positions P2' to P5' of each layer upward along the printing direction. -L1 ≦ ΔL ≦ L1 is a dead zone. After the printing center positions P2' to P5' are corrected, the control unit 14 controls the position of the torch 5 based on the corrected printing center positions P2' to P5'. This allows the distance between the object 6 and the torch 5 to be within the allowable range, preventing contact between the torch 5 and the object 6 and instability in printing due to poor shielding. In this example, since the modeling direction is vertical, there is no need to adjust the torch angle even if the modeling center position is adjusted to P2' to P5'.

[0022] Flattening the beads not only reduces the build height, but also increases the build width. Strictly speaking, this means that the build width also increases compared to the planned value. Although this has a smaller impact than the accumulation of build height errors due to stacking, the change in build width can be suppressed as follows:

[0023] If the actual build height Da is lower than the build height Ds per layer, the object 6 may be flattened. Flattening the object 6 may increase the width of the object 6, potentially making it impossible to obtain the desired shape. Therefore, a tolerance is set, and if the build height falls below a certain value (ΔL exceeds the tolerance), the temperature of the object 6 is controlled. Possible temperature control methods include (1) temporarily stopping the build and cooling the object; (2) cooling the object with water or air; and (3) reducing the wire feed rate during build to reduce heat input. Considering the build speed, method (2) is more efficient. Cooling with water, air, or carbon dioxide may also be used. For example, if ΔL exceeds the tolerance, the control unit 14 operates the cooler 9 to cool the object 6. This reduces width variations and defects due to overheating.

[0024] Next, correction of the printing path for a printing object 6 having a shape with a variable angle will be described with reference to FIG. 6. To print a printing object 6 with a variable angle, not only is the printing path (trajectory) not linear, but the angle of the torch 5 must also be changed during printing. The printing condition setting unit 13 calculates the printing width for each layer based on the shape data of the object to be printed, and sets the welding conditions for each layer by referring to a database that defines the correspondence between the printing width and the welding conditions. It also sets the printing height for each layer by referring to a database that defines the correspondence between the printing height and the welding conditions. These processes are the same as when printing in the vertical direction. However, when setting the printing width, the orientation of the object to be printed is taken into consideration. For example, if the object to be printed is inclined, the width of the object to be printed in a direction perpendicular to the inclination is used as the printing width. Furthermore, the printing center position of the next layer is calculated by adding the printing height of each layer to the upper layer along the orientation of the object to be printed (along the printing direction). The printing center positions P1 to P5 in the printing example 61 in FIG. 6 are an example of initial settings of the printing path set in this manner. The printing condition setting unit 13 also initially sets the torch angle according to the printing direction at the printing center positions P1 to P5. For example, for the printing center position P1, the torch angle is initially set to the direction (the direction of the arrow 621 of the planned value in the correction example 62) that coincides with the printing direction (tangential direction) at P1. Similarly, for P2 and P3, the torch angles are initially set to the directions of the arrows 622 and 623, respectively. The control unit 14 moves the torch 5 based on the printing center positions P1 to P5 to perform printing welding. In measuring the distance Lb, the sensor 8 is inclined at the same angle as the torch 5, so that the distance between the torch 5 and the object 6 can be measured in the same way as in the case of vertical printing. If the distance Lb between the object 6 and the torch 5 differs from the distance Ls, the printing center position is corrected according to the difference. Since the torch angle is adjusted to face the same direction as the printing direction of the object 6 during printing, when the printing center position is corrected, it is necessary to change the torch angle as well as the position of the torch 5. The control unit 14 moves the torch 5 based on the corrected printing center position, and adjusts the angle of the torch 5 based on the shape of the object 6 at the corrected printing center position. An example of the processing for correcting the printing center position when the object 6 has a shape whose angle changes will be described below.Assume that after the initial setting of the modeling path, modeling of the first layer is performed, and as a result, the modeling center position of the first layer is shifted downward by ΔL along the shape of the modeled object 6, as shown in Modification Example 62. In this case, for example, the modeling condition setting unit 13 calculates a straight line connecting the modeling center position P1 of the first layer to the modeling center position P2 of the second layer, and calculates the position of point P2' obtained by moving the modeling center position P2 toward the modeling center position P1 by ΔL along this straight line. Similarly, the modeling condition setting unit 13 calculates a straight line connecting the modeling center position P2 of the second layer to the modeling center position P3 of the third layer, and calculates the position of point P3' obtained by moving the modeling center position P3 toward the modeling center position P2 by ΔL along this straight line. The calculated P2' and P3' are the corrected modeling center positions. The printing condition setting unit 13 also calculates the inclination angle of the object 6 at the corrected printing center position P2', and corrects the torch angle so that the inclination of the torch 5 matches the calculated inclination angle and the tip of the torch 5 faces the lower layer in the printing direction. Similarly, the printing condition setting unit 13 corrects the torch angle at P3' based on the corrected printing center position P3'. The control unit 14 corrects the position of the torch 5 and the angle of the torch 5 based on the corrected printing center position P2' and the corrected torch angle at P2', and prints the second layer. After printing of the second layer is completed and the printing of the third layer begins, the printing condition setting unit 13 calculates the printing height of the second layer based on the measurement results of the sensor 8, and corrects the printing center positions P3' to P5' and the torch angle at each position as necessary. Note that if the object cannot be printed with the originally planned number of layers due to flattening of the beads, for example, the number of layers is increased. When printing an inclined object 6, if the set printing height differs from the actual printing height, the printing path may deviate, potentially resulting in an unintended shape. A significant deviation in the positional relationship between the torch 5 and the object 6 may cause an arc to be generated in an unintended direction, resulting in an unanticipated shape. According to this embodiment, the correction process described above corrects the position of the torch 5 in accordance with the tip position of the object 6 during printing, and adjusts the angle of the torch 5 to match the desired shape, thereby enabling the printing of the intended shape.

[0025] (operation) Next, the flow of the correction process for the modeling path in this embodiment will be described with reference to FIG. FIG. 7 is a flowchart illustrating an example of the formation condition setting process according to the embodiment. The shape data acquisition unit 11 acquires shape data of the object to be formed (Step S10). For example, the shape data is shape data of a thin-walled structure formed in one pass. Next, the forming condition setting unit 13 performs initial setting of the forming pass (Step S11). For example, the forming condition setting unit 13 sets the variable N to 1 and calculates the forming width of the Nth layer. For example, when N = 1, the forming condition setting unit 13 calculates the width of the bottom surface of the object to be formed as the forming width. When N > 1, the forming condition setting unit 13 calculates the sum of the forming heights up to the (N-1)th layer, and calculates the width of the object to be formed at a position in the shape data corresponding to the calculated value as the forming width. Next, the forming condition setting unit 13 calculates the welding conditions (e.g., welding speed, current, voltage, wire feed amount, etc.) for the Nth layer based on the calculated forming width, by referring to a database that defines the correspondence between the forming width and the welding speed. The printing condition setting unit 13 calculates the inclination angle of the object to be printed at a position corresponding to the Nth layer by referring to the shape data, and sets a torch angle such that the torch 5 is inclined by the calculated angle. The inclination angle of the object to be printed can be obtained, for example, by calculating the angle between a line connecting the center positions of the object to be printed for each height and a horizontal plane. The printing condition setting unit 13 calculates the printing height of the Nth layer by referring to a database that defines the correspondence between printing heights and welding conditions, calculates a position obtained by moving the object to the upper side by the printing height along the shape of the object to be printed from the (N-1)th layer to the Nth layer, and sets the calculated position as the printing center position of the Nth layer. The printing condition setting unit 13 calculates initial settings for the printing pass (printing center position, torch angle, etc.) for each layer while adding 1 to N until it reaches the top edge of the object to be printed.

[0026] Next, the control unit 14 starts the modeling based on the initial setting of the modeling path (Step S12). Modeling is performed sequentially from the first layer. Hereinafter, the layer to be modeled will be referred to as the Nth layer, etc. The welding system 1 models the Nth layer while measuring the distance Lb using the sensor 8 (Step S13). The measurement value of the sensor 8 is transmitted to the control device 10 each time. The distance detection unit 12 detects the distance Rf between the torch 5 and the modeling object 6 based on the distance Lb measured by the sensor 8. Alternatively, the distance Lb may be treated as the distance Rf. The modeling condition setting unit 13 calculates the difference ΔL between the distance Rf (or the distance Lb) detected by the distance detection unit 12 and the target distance Ls (Step S14). If ΔL is greater than a predetermined threshold Th2 (Step S15; Large), the modeling condition setting unit 13 instructs the control unit 14 to temporarily suspend modeling. The control unit 14 temporarily stops the modeling (step S16), and when the time required for the modeled object 6 to cool has elapsed, repeats the processing from step S13.

[0027] If ΔL is smaller than a predetermined threshold value Th2 and larger than a predetermined threshold value Th1 (Step S15; middle), the modeling condition setting unit 13 instructs the control unit 14 to cool the model 6. Here, threshold value Th2 is greater than threshold value Th1. The control unit 14 operates the cooler 9 to cool the model 6 (Step S17). When the time required for cooling the model 6 has elapsed, the control unit 14 stops the cooler 9. In this case, the process proceeds to Step S18.

[0028] If ΔL is smaller than the threshold value Th1 (step S15; small), the printing condition setting unit 13 corrects the printing path according to the magnitude of ΔL (step S18). For example, if ΔL=0, the printing condition setting unit 13 does not correct the printing path. If ΔL>L1 or ΔL<-L1, the printing condition setting unit 13 corrects the printing path (printing center position, torch angle). The correction method is as described with reference to FIGS. 5 and 6.

[0029] The control unit 14 continues modeling until the Nth layer is completed, while performing various processes according to the magnitude of ΔL. When the modeling of the Nth layer is completed, the modeling condition setting unit 13 determines whether the modeling is completed (Step S19). If the Nth layer reaches the end of the object opposite to the modeling start side when the modeling heights of the first to Nth layers are stacked along the shape of the object, the modeling condition setting unit 13 determines that the modeling is completed; otherwise, the modeling condition setting unit 13 determines that the modeling is incomplete. If it is determined that the modeling is completed (Step S19; Yes), the processing of FIG. 7 is completed. If it is determined that the modeling is incomplete (Step S19; No), the modeling condition setting unit 13 starts modeling of the next layer (N+1th layer) (Step S20). For the N+1th layer, the processing from Step S13 onwards is repeated.

[0030] (effect) As described above, according to this embodiment, additive manufacturing can be performed while maintaining the distance between the torch 5 and the object 6 within a certain range. In addition, additive manufacturing can be performed while controlling the torch angle according to the shape of the object 6 at the manufacturing position. This not only stabilizes the manufacturing process for each layer, but also enables the manufacturing of an object that accurately reproduces the shape of the object to be manufactured.

[0031] 9 is a diagram showing an example of the hardware configuration of the control device 10 according to the embodiment. The computer 900 includes a CPU 901, a main storage device 902, an auxiliary storage device 903, an input / output interface 904, and a communication interface 905. The control device 10 described above is implemented in the computer 900. The above-described functions are stored in the auxiliary storage device 903 in the form of a program. The CPU 901 reads the program from the auxiliary storage device 903, loads it into the main storage device 902, and executes the above-described processing in accordance with the program. The CPU 901 also allocates a storage area in the main storage device 902 in accordance with the program. The CPU 901 also allocates a storage area in the auxiliary storage device 903 for storing data being processed in accordance with the program.

[0032] A program for implementing all or part of the functions of the control device 10 may be recorded on a computer-readable recording medium, and the program may be loaded into a computer system and executed to perform processing by each functional unit. The term "computer system" as used herein includes hardware such as an OS and peripheral devices. Furthermore, if a WWW system is used, the term "computer system" also includes a homepage provision environment (or display environment). Furthermore, the term "computer-readable recording medium" refers to portable media such as CDs, DVDs, and USBs, as well as storage devices such as hard disks built into the computer system. Furthermore, if the program is distributed to the computer 900 via a communication line, the computer 900 that receives the program may load the program into the main storage device 902 and execute the above-described processing. Furthermore, the program may be for implementing part of the above-described functions, or may be capable of implementing the above-described functions in combination with a program already stored in the computer system.

[0033] As described above, several embodiments according to the present disclosure have been described, but all of these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope of the invention and its equivalents as defined in the claims, as well as in the scope and spirit of the invention.

[0034] <Additional Notes> The modeling condition setting device, the layered modeling system, the modeling condition setting method, and the program described in the embodiments can be understood, for example, as follows.

[0035] (1) The first aspect of the manufacturing condition setting device is a manufacturing condition setting device that sets manufacturing conditions when additively manufacturing an object to be manufactured using the WAAM method, and includes a means for determining whether the difference between the measured value of the distance between the torch and the object to be manufactured and the design value of the distance is within an acceptable range, and, if the difference exceeds the acceptable range, a means for correcting a target welding position included in the manufacturing conditions so that the difference falls within the acceptable range, and a means for correcting a torch angle so that it matches the manufacturing direction based on the shape of the object to be manufactured at the corrected target welding position. This allows additive manufacturing to be performed while maintaining a constant distance between the torch 5 and the object 6. Furthermore, by controlling the torch angle according to the shape of the object, it is possible to manufacture an object that accurately reproduces the shape of the object.

[0036] (2) A second aspect of the manufacturing condition setting device is the manufacturing condition setting device of (1), further comprising a means for setting the manufacturing condition to cool the object when the difference exceeds the allowable range and the difference has a magnitude that indicates an excessive temperature rise of the object. This makes it possible to suppress changes in the width of the shaped object due to flattening of the beads caused by an excessive temperature rise.

[0037] (3) A third aspect of the manufacturing condition setting device is the manufacturing condition setting device of (1) to (2), wherein, in the case where the object to be manufactured has a shape that is manufactured by stacking the object vertically, the correction means corrects the target welding position upward by a value corresponding to the difference if the difference indicates that the torch and the object are closer than the allowable range, and corrects the target welding position downward by a value corresponding to the difference if the difference indicates that the torch and the object are farther apart than the allowable range. This allows additive manufacturing to be performed while maintaining the distance between the torch 5 and the object 6 within a certain range.

[0038] (4) A fourth aspect of the manufacturing condition setting device is a manufacturing condition setting device according to any one of (1) to (3), wherein, when the object to be manufactured has an inclined shape, the correcting means, if the difference indicates that the torch and the object are closer than the tolerance range, corrects the target welding position upward along the inclined direction by a value corresponding to the difference, and corrects the torch angle so that the target welding position coincides with the manufacturing direction indicated by the shape of the object to be manufactured at the corrected target welding position and the tip of the torch faces the lower layer direction in the manufacturing process; and, if the difference indicates that the torch and the object are farther apart than the tolerance range, corrects the target welding position downward along the inclined direction by a value corresponding to the difference, and corrects the torch angle so that the target welding position coincides with the manufacturing direction indicated by the shape of the object to be manufactured at the corrected target welding position and the tip of the torch faces the lower layer direction in the manufacturing process. This allows additive manufacturing to be performed while maintaining the distance between the torch 5 and the object 6 within a certain range.

[0039] (5) A fifth aspect of the forming condition setting device is the forming condition setting device of (2), in which, if the difference is equal to or less than a predetermined first threshold, the means for setting cooling determines to cool the formed object by spraying water or gas. This allows the object to be cooled.

[0040] (6) A sixth aspect of the manufacturing condition setting device is a manufacturing condition setting device of (2) or (5), in which, if the difference is equal to or greater than a predetermined second threshold value that is greater than the first threshold value, the means for setting cooling determines to temporarily suspend manufacturing. This allows the object to be cooled.

[0041] (7) The seventh aspect of the additive manufacturing system is an additive manufacturing system that additively manufactures an object to be manufactured using the WAAM method, and includes a welding system having a torch and a sensor that measures the distance to an object fixed in a fixed positional relationship with the torch, a control device that controls the welding system, and a manufacturing condition setting device described in (1) to (6).

[0042] (8) An eighth aspect of the additive manufacturing system is an additive manufacturing system for additively manufacturing an object by the WAAM method, and includes a welding system having a torch, a sensor for measuring the distance to a fixed object fixed in a certain positional relationship with the torch, and a cooling machine for cooling the object; The welding system includes a control device that controls the welding system, and the forming condition setting device described in (2), (5) to (6).

[0043] (9) A ninth aspect of the manufacturing condition setting method is a manufacturing condition setting method executed by a computer for setting manufacturing conditions when additive manufacturing an object to be manufactured using the WAAM method, and includes the steps of: determining whether the difference between the measured value of the distance between the torch and the object to be manufactured and the design value of the distance is within an acceptable range; and, if the difference exceeds the acceptable range, correcting the target welding position included in the manufacturing conditions so that the difference is within the acceptable range, and correcting the torch angle so that it matches the manufacturing direction based on the shape of the object to be manufactured at the corrected target welding position.

[0044] (10) A program according to the tenth aspect causes a computer to execute a process for setting manufacturing conditions when additively manufacturing an object to be manufactured using the WAAM method, the process including the steps of determining whether the difference between the measured value of the distance between the torch and the object to be manufactured is within an acceptable range and, if the difference exceeds the acceptable range, correcting the target welding position included in the manufacturing conditions so that the difference falls within the acceptable range, and correcting the torch angle so that it matches the manufacturing direction based on the shape of the object to be manufactured at the corrected target welding position. [Explanation of symbols]

[0045] 1. Welding system 2. Welding robot 3. Welding machine 4. Wire feeder 5. Torch 6...modeled object 7. Positioning device 8. Sensor 9...Cooler 10. Control device 11. Shape data acquisition section 12. Distance detection unit 13. Printing condition setting section 14. Control section 15...Storage section 100···Additive Manufacturing System 900···Computer 901 CPU 902...Main memory 903...Auxiliary storage device 904 Input / Output Interface 905···Communication Interface

Claims

1. A modeling condition setting device that sets modeling conditions when additively manufacturing a modeling object using the WAAM method, a means for determining whether a difference between a measured value of the distance between the torch and the object and a design value of the distance is within an allowable range; a means for correcting a target welding position included in the building conditions so that the difference falls within the allowable range when the difference exceeds the allowable range, and for correcting a torch angle so that the torch angle coincides with the building direction based on the shape of the object to be built at the corrected target welding position; A molding condition setting device having the same.

2. a means for setting, as the modeling condition, a condition that the object is cooled, when the difference exceeds the allowable range and has a magnitude that indicates an excessive temperature rise of the object; The shaping condition setting device according to claim 1 , further comprising:

3. In the case where the object to be manufactured has a shape that is manufactured by stacking the objects vertically, The means for correcting includes: If the difference indicates that the torch and the workpiece are closer than the tolerance range, correct the target welding position upward by a value corresponding to the difference; If the difference indicates that the torch and the workpiece are spaced apart by more than the tolerance, the target welding position is corrected downward by a value corresponding to the difference.

3. The molding condition setting device according to claim 1 or 2.

4. When the object to be shaped has an inclined shape, The means for correcting includes: If the difference indicates that the torch and the object are closer than the tolerance range, the target welding position is corrected to an upper layer side along the inclined direction by a value corresponding to the difference, and the torch angle is corrected so that the target welding position after the correction coincides with the printing direction indicated by the shape of the object to be printed and the tip of the torch is directed toward a lower layer in the printing; If the difference indicates that the torch and the object are apart from each other beyond the tolerance range, the target welding position is corrected toward the lower layer along the inclined direction by a value corresponding to the difference, and the torch angle is corrected so that the target welding position after the correction coincides with the printing direction indicated by the shape of the object to be printed and the tip of the torch faces the lower layer direction in printing.

3. The molding condition setting device according to claim 1 or 2.

5. If the difference is equal to or smaller than a predetermined first threshold, the means for setting cooling determines to cool the object by spraying water or gas. The molding condition setting device according to claim 2 .

6. If the difference is equal to or greater than a predetermined second threshold value that is greater than the first threshold value, the means for setting cooling determines to suspend the building. The molding condition setting device according to claim 5 .

7. An additive manufacturing system that additively manufactures an object to be manufactured by the WAAM method, a welding system including a torch and a sensor for measuring a distance to a workpiece fixed in a fixed positional relationship with the torch; a control device for controlling the welding system; The forming condition setting device according to claim 1 ; An additive manufacturing system having:

8. An additive manufacturing system that additively manufactures an object to be manufactured by the WAAM method, a welding system including a torch, a sensor for measuring a distance to a workpiece fixed in a fixed positional relationship with the torch, and a cooler for cooling the workpiece; a control device for controlling the welding system; The forming condition setting device according to claim 2 ; An additive manufacturing system having:

9. A modeling condition setting method executed by a computer for setting modeling conditions when additively manufacturing a modeling object by the WAAM method, comprising: a step of determining whether a difference between a measured value of the distance between the torch and the object and a design value of the distance is within an allowable range; If the difference exceeds an allowable range, correcting a target welding position included in the building conditions so that the difference falls within the allowable range, and correcting a torch angle so that it coincides with a building direction based on a shape of the object to be built at the corrected target welding position; A method for setting modeling conditions.

10. On the computer, A process for setting the modeling conditions when additively manufacturing an object using the WAAM method, a step of determining whether a difference between a measured value of the distance between the torch and the object and a design value of the distance is within an allowable range; If the difference exceeds an allowable range, correcting a target welding position included in the building conditions so that the difference falls within the allowable range, and correcting a torch angle so that it coincides with a building direction based on a shape of the object to be built at the corrected target welding position; A program that executes a process having the above steps.

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