Layered molding method, layered molding apparatus, and model display apparatus

Abstract

The layering molding method has a process of dividing a three-dimensional model shape into a plurality of layers and dividing each of the divided layers into a plurality of weld bead models. The trapezoidal weld bead model has four vertices. In the process of dividing into the weld bead models, a later-formed weld bead model is arranged adjacent to an earlier-formed weld bead model in such a manner that the earlier-formed weld bead model has an overlapping portion with the later-formed weld bead model. In addition, the later-formed weld bead model is rotated and moved from the center point of the vertices at both ends of the bottom side of the later-formed weld bead model, which is away from the overlapping portion, to change the shape of the trapezoidal weld bead model.

Description

Technical Field

[0001] This invention relates to a layered modeling method, a layered modeling apparatus, and a model display device. Background Technology

[0002] In recent years, the demand for 3D printers as a means of production has increased, and research and development have been carried out toward the practical application of 3D models using metal materials. As a technique for creating three-dimensional objects using metal materials, there are methods that use heat sources such as electric arcs to melt and solidify filler material (welding wire) to create layers of weld beads that are stacked into the desired shape.

[0003] In addition, it is known that when manufacturing such objects, the cross-sectional shape of the weld bead is modeled for the purpose of computer-aided design support or automated control (e.g., Patent Documents 1 and 2).

[0004] Patent Document 1 describes using an elliptical weld bead model to change the shaping conditions so that the difference between the target shape of the object and the predicted shape based on a measured database is below an acceptable value. Patent Document 2 describes predicting the shape of the weld bead in each layer and step based on workpiece conditions such as joint shape, plate thickness, bevel angle, and width, and determining the appropriate target position of the welding torch in the next layer and the next step based on the predicted weld bead shape.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2018-27558

[0008] Patent Document 2: Japanese Patent Application Publication No. 63-84776 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] However, when stacking weld beads formed by melting and solidifying the filler material, various factors such as the accumulation of molten metal sagging during melting, the accumulation of input heat, and the unevenness of the solidified weld bead surface affect the shape of the object. For example, as Figure 17 As shown, when welding models Mo of the same shape are stacked in a 4-column × 4-layer configuration, sometimes the outer edge shape of the actual manufactured object W does not match the outer edge shape of the welding model Mo, as shown by the solid line.

[0011] Therefore, we also considered adjusting the shape of the weld bead model precisely according to the formation conditions of the weld bead, but the calculation and processing became complicated, and due to the scale of the object, it was impossible to create the layering plan in a realistic time.

[0012] The purpose of this invention is to provide a method, apparatus, and model display device for manufacturing a model that can be adjusted with simple calculations for the fabrication of a weld pattern and can shape a target shape with high reproducibility.

[0013] Solution for solving the problem

[0014] The present invention is composed of the following structure.

[0015] (1) A method for creating a shaped object by stacking weld beads formed by melting and solidifying filler material onto a base, wherein...

[0016] The layered modeling method has the following characteristics:

[0017] The process of reading in the three-dimensional shape data of the object;

[0018] The process of dividing the shape of a three-dimensional model based on the three-dimensional shape data into multiple layers, and further dividing each layer into multiple weld bead models corresponding to the weld bead shape of the deposited weld bead; and

[0019] The process of repeatedly forming the weld beads along the segmented weld bead model from the lower to the upper layers of the multiple layers, thereby stacking the weld beads, is described.

[0020] The weld bead model is trapezoidal in shape. In a cross-section perpendicular to the long side of the weld bead, the bottom edge of the base side is parallel to the top edge of the opposite side of the base. Furthermore, the pair of opposite sides of the weld bead model arranged in the same layer are not parallel to each other in the arrangement direction.

[0021] The process of dividing the weld bead model into the plurality of weld patterns includes the following steps:

[0022] Within the same layer, the weld bead model corresponding to the first formed weld bead and the weld bead model corresponding to the weld bead formed subsequently adjacent to it are arranged in a manner that they overlap with each other.

[0023] Using the vertex located at the end of the bottom edge of the weld bead model on the side furthest from the overlapping portion, one of the four vertices of the weld bead model formed later as the center, the other three vertices are rotated and moved respectively, thereby changing the shape of the weld bead model on the side formed later.

[0024] (2) A layered molding device, which layers weld beads formed by melting and solidifying filler material onto a base to create a molded object, wherein...

[0025] The stacked molding device includes:

[0026] The input unit reads in the three-dimensional shape data of the object;

[0027] The model setting unit divides the shape of the solid model based on the three-dimensional shape data into multiple layers, and further divides each layer into multiple weld bead models corresponding to the weld bead shape of the deposited weld bead; and

[0028] The molding section repeatedly performs the process of forming the weld beads along the segmented weld bead model from the lower layer to the upper layer of the multiple layers, thereby stacking the weld beads.

[0029] The weld bead model is trapezoidal in shape. In a cross-section perpendicular to the long side of the weld bead, the bottom edge of the base side is parallel to the top edge of the opposite side of the base. Furthermore, the pair of opposite sides of the weld bead model arranged in the same layer are not parallel to each other in the arrangement direction.

[0030] The model setting unit arranges the weld bead model corresponding to the first formed weld bead and the weld bead model corresponding to the subsequently formed weld bead adjacent to it in the same layer in such a way that they have overlapping portions.

[0031] The model setting unit takes the vertex located at the end of the bottom edge of the weld bead model on the side furthest from the overlapping portion, one of the four vertices of the weld bead model formed later, as the center, and rotates and moves the other three vertices respectively, thereby changing the shape of the weld bead model formed later.

[0032] (3) A model display device, wherein...

[0033] The model display device includes:

[0034] The input unit receives information about the weld bead model set by the model setting unit of the stacked modeling apparatus described in (2); and

[0035] The display unit shows the information of the input weld model.

[0036] Invention Effects

[0037] According to the present invention, the weld bead model used for fabrication of the stacking plan can be adjusted with simple calculations, and the target shape can be modeled with high reproducibility. Attached Figure Description

[0038] Figure 1 This is a schematic diagram showing the structure of the layered molding device.

[0039] Figure 2 This is a schematic perspective view showing the appearance of the weld bead formed on the base plate.

[0040] Figure 3 This is a functional block diagram of the display device.

[0041] Figure 4 This is a flowchart showing the sequence of setting up weld patterns that correspond to the shape of the object.

[0042] Figure 5 (A) to (D) are illustrations showing the setup of the weld bead model.

[0043] Figure 6 This is an explanatory diagram showing the cross-sectional shape of the trapezoidal weld bead model and the actual cross-sectional shape of the weld bead.

[0044] Figure 7 This is an explanatory diagram showing the situation where the shape of the trapezoidal weld bead model is changed.

[0045] Figure 8 It is shown Figure 7 A diagram illustrating the details of the rotational motion of the trapezoidal weld bead model shown.

[0046] Figure 9 It is a graph that uses a linear function to represent the relationship between the radius distance x and the angle θ.

[0047] Figure 10 (A) is a graph that uses a zero-order function to represent the relationship between the radius distance x and the angle θ. Figure 10 (B) is an illustrative representation of the use of Figure 10 The diagram shown in (A) illustrates how the function determines the shape of the weld bead model at angle θ.

[0048] Figure 11 (A) is a graph that uses a cubic function to represent the relationship between the radius distance x and the angle θ. Figure 11 (B) is an illustrative representation of the use of Figure 11 The diagram shown in (A) illustrates how the function determines the shape of the weld bead model at angle θ.

[0049] Figure 12 It is a graph that uses an nth-order function to represent the relationship between the radius distance x and the angle θ.

[0050] Figure 13 It shows the use Figure 12 The diagram illustrates how the shape of the weld bead model is determined by an nth-order function at angle θ.

[0051] Figure 14 It shows that Figure 13 The diagram illustrates the arrangement of weld bead models within a trapezoidal weld bead model.

[0052] Figure 15This is an illustrative diagram showing a weld bead model that takes into account the vertical weld bead.

[0053] Figure 16 (A) and (B) are schematic diagrams showing the outer edge shape of a stacked model that takes into account the vertical weld bead and the stacked shape created by using the weld bead model.

[0054] Figure 17 This is an explanatory diagram showing the outer edge shape of the weld bead model and the object created using a conventional layering scheme. Detailed Implementation

[0055] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0056] In the layered modeling method of the present invention, a layering plan is made using a weld bead model obtained by simulating the weld bead formed by melting and solidifying the filler material, and a model is made by forming the weld bead on the base based on the layered plan.

[0057] <Layered Artwork>

[0058] Figure 1 This is a schematic diagram showing the structure of the layered molding device.

[0059] The stacking molding apparatus 100 is an apparatus for creating molded objects or as a rough material for obtaining molded objects of a desired shape, and includes a molding unit 11, a power supply unit 13, and a controller 15 for comprehensively controlling the molding unit 11 and the power supply unit 13. It should be noted that the stacking molding apparatus 100 shown here uses an electric arc to melt and solidify the filler material M to form weld beads B, and stacks multiple weld beads B in sequence to create a molded object W, but the stacking molding method is not limited to this.

[0060] The shaping section 11 includes: a welding robot 19 having a welding torch 17 on its front end axis; and a filler material supply section 21 that supplies filler material (welding wire) M to the welding torch 17.

[0061] The welding robot 19 is a multi-joint robot, and a welding torch 17 is supported on the front axis of the robotic arm in a manner that allows for the continuous supply of filler material M. The position and orientation of the welding torch 17 can be arbitrarily set in three dimensions within the range of degrees of freedom of the robotic arm.

[0062] The welding torch 17 supports the filler material M and generates an electric arc from the tip of the filler material M under a shielding gas atmosphere. The welding torch 17 has a shielding nozzle (not shown) and supplies shielding gas from the shielding nozzle. As an arc welding method, it can be any of the following: consumable electrode type such as overlay arc welding or carbon dioxide gas arc welding; or non-consumable electrode type such as TIG welding or plasma arc welding, which is appropriately selected according to the shape to be produced.

[0063] For example, in the case of a consumable electrode type, a conductive tip is disposed inside the protective nozzle, and the filler material M supplied with molten current is held in the conductive tip. While holding the filler material M, the welding torch 17 generates an arc from the front end of the filler material M under a protective gas atmosphere. The filler material M is fed from the filler material supply section 21 to the welding torch 17 via a delivery mechanism (not shown) mounted on a robotic arm or the like. Furthermore, if the continuously fed filler material M is melted and solidified while the welding torch 17 is moved, a linear weld bead B, which is the molten solidified filler material M, is formed on the base plate 25.

[0064] It should be noted that the heat source for melting the filler material M is not limited to the electric arc described above. For example, other heat sources such as heating methods using both electric arcs and lasers, heating methods using plasma, and heating methods using electron beams or lasers can also be used. When using electron beams or lasers for heating, the amount of heat can be controlled more precisely, and the state of the weld bead can be maintained more appropriately, thereby contributing to further improvement in the quality of the molded object.

[0065] The filler material M can be any commercially available welding wire. For example, welding wires specified such as solid welding wires for MAG welding and MIG welding of mild steel, high-tensile steel and low-temperature steel (JIS Z 3312) and flux-cored welding wires for arc welding of mild steel, high-tensile steel and low-temperature steel (JIS Z 3313) can be used.

[0066] The controller 15 includes an input unit 31, a model setting unit 33, a stacking planning unit 35, a storage unit 27, a communication unit 39, and a control unit 41 connected to them. The controller 15 is composed of a computer device equipped with a CPU, memory, storage devices, etc.

[0067] The input unit 31 reads in the three-dimensional shape data (CAD data, etc.) of the object to be created. The model setting unit 33 divides the shape of the solid model based on the read-in three-dimensional shape data into multiple layers and generates layer shape data representing the shape of each layer. Furthermore, the generated layer shape data is divided into multiple weld bead models, as described later.

[0068] The layering planning unit 35 determines the movement trajectory of the welding torch 17, which forms the weld bead along the segmented weld bead model, and various welding conditions. Furthermore, using the determined movement trajectory and welding conditions, it creates a driver program to drive each part of the modeling unit 11 and the power supply unit 13. This driver program is stored in the storage unit 37. The modeling program described here is the command code used to instruct the modeling unit 11 and the power supply unit 13 to perform the steps of forming the weld bead B, designed based on the input three-dimensional shape data of the model W and through prescribed calculations.

[0069] The control unit 41 executes the driver program stored in the storage unit 37 to drive the welding robot 19, power supply unit 13, and other components. Thus, the welding robot 19 receives instructions from the controller 15, causing the welding torch 17 to move along a trajectory corresponding to the lamination plan. Furthermore, the movement of the welding robot 19 and the welding torch 17 together melts the filler material M and supplies the molten filler material M onto the base plate 25. In this way, a linear weld bead B is formed on the base plate 25.

[0070] Figure 2 This is a schematic perspective view showing the appearance of the weld bead B formed on the base plate 25.

[0071] like Figure 2 As shown, a weld layer 45 is formed at a height h by repeatedly forming weld beads B on the base plate 25, thereby solidifying and arranging multiple linear weld beads B. Figure 2 The diagram shows the initial weld bead layer 45, but the shape is achieved by repeatedly stacking the same weld bead layer on top of this weld bead layer 45. Figure 1 The image shows an example of a multi-layered structure called W.

[0072] It should be noted that the base plate 25 is made of metal plates such as steel plates, but is not limited to plate shape, and can also be a base of other shapes such as block or rod.

[0073] Figure 1 The model setting unit 33, the stack-up planning unit 35, and other computing units shown can also be located outside the controller 15. For example, the computing units can be installed on an external computer PC, such as a server or terminal, connected to the communication unit 39 via a network. By installing the computing units on an external computer PC, the desired driver can be created without the need for the stack-up modeling device 100, and the programming process does not become complicated. Furthermore, by transferring the created driver to the storage unit 37 of the controller 15, the modeling unit 11 and the power supply unit 13 can be operated in the same way as when the driver is created by the controller 15.

[0074] Furthermore, as detailed below, a display unit 43, such as an LCD, can be connected to the controller 15, enabling the display unit 43 to display model information. For example, by displaying information such as the weld bead model set by the model setting unit 33 on the display unit 43, the operator can easily confirm various information about the stacking plan or adjust the plan content. That is, it can provide design support for the model. Alternatively, a display unit 47, such as a monitor connected to an external computer PC, can also have the same function of displaying information such as the weld bead model. Thus, the stacking modeling apparatus 100 can have a structure that provides design support for the model, or a structure in which a device equipped with a display unit 43 is connected externally to the stacking modeling apparatus 100.

[0075] Figure 3 This is a functional block diagram of the model display device 200.

[0076] The model display device 200, which supports the design of sculpted objects, includes an input unit 51 for inputting information about the weld bead model set by the model setting unit 33, and a display unit 53 for displaying the input weld bead model information. This allows for visual confirmation of the shape, size, or difference between the weld bead model displayed on the display unit 53 and the actual weld bead shape. Alternatively, a display data generation unit 55 can be included to process the input weld bead model information and generate display data. In this case, the weld bead model can be re-set by the operator inputting instructions to the input unit 51 to adjust various conditions.

[0077] <Layered Design Methods>

[0078] The aforementioned shape W is formed by stacking multiple weld beads B based on a stacking plan that represents the formation sequence of weld beads and welding conditions. Specifically, using... Figure 1 The controller 15 or an external computer PC shown creates a stacking plan corresponding to the information input by the operator and generates a driver based on the created stacking plan. Furthermore, the control unit 41 executes the generated driver to drive the shaping unit 11 and the power supply unit 13, thereby creating a model W with the desired shape according to the stacking plan.

[0079] The aforementioned layering scheme includes the process of transforming the shape of the object W into an assembly of weld bead models representing individual weld bead shapes of the deposited weld beads B. Each weld bead model is a shape model formed by simulating the deposited weld beads and extending along one direction, possessing positional information (information on the torch's movement trajectory), and information such as the size, length, or cross-sectional shape of each weld bead. If the torch 17 is moved along the weld bead model while simultaneously forming weld bead B, the object W is ultimately obtained.

[0080] <Setting up the weld bead model>

[0081] (Model Segmentation)

[0082] Figure 4 This is a flowchart showing the sequence of setting up weld patterns corresponding to the shape of the object W. Figure 5 (A) to (D) are illustrations showing the setup of the weld bead model.

[0083] First, read in the 3D shape data (CAD data, etc.) representing the shape of the object to be modeled (S1). The shape of the read-in 3D shape data is as follows: Figure 5 As shown in (A), the weld bead is divided into multiple layers (S2) by slicing with a surface 61 orthogonal to the stacking direction H of the weld bead. The method of division is not particularly limited, and known methods can be used.

[0084] Next, as Figure 5 As shown in (B), each layer BL is divided into multiple rectangular weld bead models BM0 (S3) using surface 63 in a manner corresponding to the weld bead shape of the weld bead. Figure 5 The rectangular weld bead model BM0 shown in (B) is... Figure 5 The model is a continuous linear solid model in the depth direction. However, in the following description, the rectangular shape in the cross-section orthogonal to the long side direction (depth direction) of the rectangular weld bead model BM0 will be referred to as the rectangular weld bead model BM0. That is, the above-described segmentation process of the rectangular weld bead model BM0 is performed on the entire layer, dividing the cross-sectional shape of each layer BL according to weld bead units. Thus, multiple rectangular weld bead models BM0 are configured in each layer BL. When segmenting the rectangular weld bead model BM0, conditions such as keeping the weld bead cross-sectional area constant in the orthogonal cross-section in the long side direction of the weld bead can also be specified in each model.

[0085] Then, the segmented rectangular weld bead model BM0 is applied to a trapezoid as a simple geometric shape and transformed into a trapezoidal weld bead model BM (S4). The trapezoidal weld bead model BM is a trapezoidal shape with four vertices, in a cross section perpendicular to the long side of the weld bead, with the bottom edge 65 located on the side of the base plate 25 and the top edge 67 opposite to the bottom edge 65 in the weld bead stacking direction being parallel to each other, and a pair of side edges 69 and 71 opposite to each other in the weld bead arrangement direction within layer BL being non-parallel to each other.

[0086] The trapezoidal shape can be set arbitrarily, but it can also be set by referring to a database if the relationship between welding conditions and weld shape is managed in advance. For example, various parameters such as the lengths of the base 65, top 67, side 69, and 71 of the trapezoid, as well as the angles formed by the base 65 and the side 69 and 71 can be appropriately determined.

[0087] Next, as Figure 5 As shown in (D), the shape of a specific trapezoidal weld bead model among multiple trapezoidal weld bead models BM is changed (S5). This process is performed by taking into account the effect of adjacent weld beads overlapping each other and correcting the position of each vertex of the trapezoidal weld bead model BM corresponding to the weld bead formed later in the manufacturing process.

[0088] Figure 6 This is an explanatory diagram showing the cross-sectional shape of the trapezoidal weld bead model BM and the actual cross-sectional shape of the weld bead B.

[0089] like Figure 6 As shown, when forming a weld bead B simply by arranging trapezoidal weld bead models BM of the same shape, depending on the situation, it is sometimes impossible to absorb the changes in weld bead shape caused by the overlap of adjacent weld beads. In this case, the difference δ between the surface shape of the actually formed weld bead and the shape of the trapezoidal weld bead model BM may cause the model to deviate from the target shape.

[0090] Therefore, by considering the overlap between adjacent weld beads, the vertex positions of the trapezoidal weld bead model BM are changed, thus making the shape of the trapezoidal weld bead model BM closer to the actual shape of the weld bead. Here, it is envisioned that the weld bead is changed from... Figure 5 The trapezoidal weld bead model BM, which is the left end of (C), is stacked sequentially, so the vertices of the trapezoidal weld bead model BM, which is the left end of the overlapping side, do not rotate or move.

[0091] (Shape change of the trapezoidal weld bead model)

[0092] Figure 7 This is an explanatory diagram illustrating the case where the shape of the trapezoidal weld bead model BM is changed. In the following description, the description of the same component and the same part will be omitted or simplified by assigning the same reference numerals.

[0093] Will Figure 7 Among the multiple trapezoidal weld bead models BM shown, the trapezoidal weld bead model located within the same layer BL and formed first is designated as BMa, and the trapezoidal weld bead model located at the position of the later formed weld bead is designated as BMb (shown as dashed lines). In addition, the trapezoidal weld bead model BMa formed first and the trapezoidal weld bead model BMb formed later are arranged with an overlap of 73 (shown as dotted lines).

[0094] Here, the vertex of the trapezoidal weld bead model BMb (shown in dashed lines) on the side closest to the overlapping portion 73 on the bottom edge 65 is designated as P1, and the vertex of the side furthest from the overlapping portion 73 on the bottom edge 65 is designated as P4. Additionally, the vertex of the pair of vertices at both ends of the upper edge 67 in the weld bead model BMb on the side closest to the overlapping portion 73 is designated as P2, and the vertex on the side furthest from the overlapping portion 73 is designated as P3. Furthermore, the intersection point of the side edge 69 on the overlapping portion 73 side of the weld bead model BMb and the outer periphery (in this case, side edge 71) of the first-formed weld bead model BMa is designated as Q1. Additionally, the vertex of the first-formed weld bead model BMa on the side of the overlapping portion 73 on the bottom edge 65 is designated as Q2.

[0095] Furthermore, taking vertex P4 of the newly formed trapezoidal weld bead model BMb (shown as a dashed line) as the center, the other three vertices P1, P2, and P3 are rotated and moved respectively. Here, the trapezoidal weld bead model BMb is rotated and moved in the direction indicated by the arrow (clockwise). In this way, vertex P4, the center of rotation, remains unchanged, vertex P1 becomes vertex P1a, vertex P2 becomes vertex P2a, and vertex P3 becomes vertex P3a. That is, the rotated trapezoidal weld bead model BMb moves while maintaining the relative positions of the four vertices P1, P2a, P3a, and P4a constant before and after the rotation, thus becoming a trapezoidal weld bead model BMb with the same shape as before the rotation.

[0096] The rotational motion of the trapezoidal weld bead model BMb described above will be explained in more detail.

[0097] Figure 8 It is shown Figure 7 A diagram illustrating the details of the rotational motion of the trapezoidal weld bead model BMb.

[0098] exist Figure 7 The example shown illustrates rotating the trapezoidal weld bead model BMa while maintaining its original shape, but this is not a limitation; the trapezoidal shape can also be altered. For example... Figure 8 As shown, in the trapezoidal weld bead model BMb (shown as dashed lines), vertex P1 is rotated and moved around vertex P4 by an angle θ1 to become vertex P1a. Similarly, vertex P2 is rotated and moved by an angle θ2 to become vertex P2a, and vertex P3 is rotated and moved by an angle θ3 to become vertex P3a. The angle θj (j = 1, 2, 3) for rotating and moving each vertex Pi (i = 1, 2, 3) can be set according to the radius distance xk (k = 1, 2, 3) from vertex P4, which serves as the center of rotation. It should be noted that the radius distance X4 of vertex P4 is 0.

[0099] Alternatively, the rotation and movement of each vertex Pi can be assigned a condition that makes the cross-sectional area of ​​the rotated weld bead model BMb equal to that of the trapezoidal weld bead model BMb before deformation. The trapezoidal weld bead models BMa and BMb, configured in this way, are set as the weld bead models for the stacking plan, and a stacking plan is created (S6).

[0100] exist Figure 7 as well as Figure 8 The diagram shows the trapezoidal weld bead model BMb adjacent to the trapezoidal weld bead model BMa, as well as the weld bead model used in the stacking scheme, but it can also be shown as... Figure 5 As shown in (D), multiple trapezoidal weld bead models BMb are repeatedly arranged. These trapezoidal weld bead models BMb are all set to the same shape, thus making it easy to set up the weld bead model. In addition, the rotation and movement of the vertex Pi can be changed according to the placement of the model, so that the shape of the trapezoidal weld bead model BMb can be changed appropriately.

[0101] <Example 1 of a variation of the weld bead model used in a layered design>

[0102] Next, it will be explained that the trapezoidal weld bead model BMb obtained by rotating and moving each vertex Pi as described above is further designed as a weld bead model for a stacking plan that approximates the shape of the actual weld bead.

[0103] In this layered design, the weld bead model used replaces the trapezoidal weld bead model BMb with four vertices, and is set as... Figure 7 The model is a pentagonal shape shown by marking the cross-section lines within the thick lines. That is, the region with 5 vertices, bounded by the aforementioned vertex Q2, intersection Q1, vertex P2a, vertex P3a, and vertex P4, is set as the weld bead model BMR used in the stacking plan.

[0104] In addition, the trapezoidal weld bead model BMa, which corresponds to the weld bead initially formed in the same layer BL, is treated as the weld bead model BMR for the stacking plan, retaining its original shape.

[0105] Each weld bead model BMR can also be set to have the same cross-sectional area as the trapezoidal weld bead models BMa and BMb before deformation. That is, Figure 7 The cross-sectional area of ​​the trapezoidal weld bead model BMb, which is composed of vertices P1, P2, P3, and P4, is equal to the cross-sectional area of ​​the pentagonal weld bead model BMR, which is composed of vertices Q2, intersection Q1, and vertices P2a, P3a, and P4.

[0106] When using a weld bead model BMR as the weld bead model for a stack-up plan, adjacent weld bead models BMR are arranged along one side edge 71 of the trapezoidal weld bead model BMa corresponding to the previously formed weld bead. Therefore, no overlap between the two models is generated, and a more accurate stack-up plan can be created.

[0107] (Method for setting the rotation and movement of each vertex)

[0108] The aforementioned Figure 8 The rotational movement angle θj (J = 1, 2, 3) of the shown vertex Pi can be set according to the welding conditions and the formation path of the weld bead. Alternatively, it can vary for each vertex. Welding conditions can include, for example, the welding method such as cold metal transfer welding (CMT), pulsed arc welding, or low voltage (CV) welding, as well as welding current, welding voltage, filler material supply speed, or welding speed. Formation paths can include straight paths, curved paths, upward paths, or downward paths. Furthermore, the angle θj can also be set as a function of the radius distance xk. In this case, the coefficients of each function are fitted in a way that matches the shape of the pre-determined experimental model.

[0109] Figure 9 This is a graph representing the relationship between radius distance x and angle θ using a linear function. For example, a linear function can be represented by θ = ax + b, with coefficients a and b set appropriately. In this case, the angle θ changes linearly according to the radius distance of each vertex P1, P2, and P3 from vertex P4; the closer to vertex P4, the smaller the angle θ.

[0110] The angle θ described above is not limited to a linear function; various functions can be used instead.

[0111] Figure 10 (A) is a graph that uses a zero-order function to represent the relationship between the radius distance x and the angle θ. Figure 10 (B) is an illustrative representation of the use of Figure 10 The diagram shown in (A) illustrates how the function determines the shape of the weld bead model at angle θ.

[0112] In this case, the angle θ is constant at each vertex P1, P2, and P3, and the trapezoidal weld bead models BMb (shown as dashed lines) formed by the four vertices merge together. Additionally, the weld bead models BMR formed by the five vertices each take on a shape shown in cross-section.

[0113] Figure 11 (A) is a graph that uses a cubic function to represent the relationship between the radius distance x and the angle θ. Figure 11 (B) is an illustrative representation of the use of Figure 11 The diagram (A) illustrates how the function determines the shape of the weld bead model at angle θ. A cubic function, for example, is derived from θ = cx. 3 +dx 2 +e+f indicates that the coefficients c, d, e, and f are set appropriately.

[0114] In this case, the angle θ increases sharply near the radius distance x1 of the vertex P1. Therefore, the vertex P1 of the trapezoidal weld bead model BMb is raised beyond the side 71 of the adjacent trapezoidal weld bead model BMa, resulting in a weld bead model shape that is closer to the actual weld bead shape.

[0115] Figure 12 It is a graph representing the relationship between the radius x and the angle θ using an nth-order function (n is, for example, 1.5 or 2). This nth-order function is, for example, θ = gx. n +h indicates that the coefficients g and h are set appropriately. In this case, the polarity (direction of rotation) of angles θ1, θ2 and θ3 is reversed.

[0116] Figure 13 It shows the use Figure 12 The diagram illustrates how the shape of the weld bead model is determined by an nth-order function at angle θ.

[0117] like Figure 13 As shown, vertices P1 and P2 of the trapezoidal weld bead model BMb rotate clockwise around vertex P4, while vertex P3 rotates counterclockwise. By making the direction of this rotation different for each vertex, the degree of freedom in setting the shape of the weld bead model BMR is increased, allowing the weld bead model BMR to more closely resemble the shape of an actual weld bead. It should be noted that the same effect is achieved when using the trapezoidal weld bead model BMb.

[0118] Figure 14 It shows that Figure 13 The diagram illustrates the arrangement of weld bead model BMR within the trapezoidal weld bead model BMa.

[0119] like Figure 14 As shown, by adjusting the degree and coefficient of the nth-order function representing the relationship between the radius distance x and the angle θ, the approximation to the shape of the actual weld bead can be further improved.

[0120] Based on the aforementioned layered modeling method, the shape of the weld bead model can be easily adjusted through simple calculations, such as rotating and moving each vertex of the trapezoidal weld bead model. Furthermore, by setting the rotation angle for rotating and moving the three vertices according to the welding conditions or formation path of the weld bead, the shape of the weld bead model can be set to a more appropriate shape based on the location of the weld bead and the layering pattern. Moreover, by making the rotation angle different for each vertex, even complex shapes that cannot be represented by simple rotation of a trapezoid can be easily reproduced. In this way, it is possible to easily create objects with shapes that more closely resemble the target shape.

[0121] Furthermore, by setting the rotation angles for rotating and moving the three vertices based on a pre-defined formula, the coefficients in the formula can be adjusted to make the weld bead model more similar to the shape of the actual weld bead.

[0122] Furthermore, when using a weld bead model (BMR) with five vertices based on a rotated trapezoidal weld bead model for stacking, the shape of the weld bead formed adjacent to an existing weld bead can be reproduced more faithfully. That is, when a weld bead is formed adjacent to an existing weld bead, the cross-sectional shape of the weld bead becomes closer to a parallelogram than a trapezoidal shape. Even in such cases, by fitting using a weld bead model (BMR) with five vertices, the model can approximate the actual weld bead shape well.

[0123] <Example 2 of the variation of the weld bead model used in the stacking scheme>

[0124] When forming a weld bead, if a new weld bead is formed on top of a lower weld bead, a portion of the upper weld bead may sometimes droop downwards towards the lower layer. When a portion of the weld bead droops, the weld bead's height decreases due to this droop. Therefore, the actual weld bead's height tends to be lower than the planned height. Thus, it is preferable to generate a weld bead model that takes into account the drooping weld bead during the layer stacking planning stage.

[0125] Figure 15 This is an illustrative diagram showing the vertical weld bead model (BMRs) that takes into account the weld bead deposition.

[0126] Regarding the upper trapezoidal weld bead models BMa and BMb in the stacked trapezoidal weld bead models BMa and BMb, downward-extending drooping portions 75A and 75B are added to the ends of the bottom edges 65, thus changing them into weld bead models BMRs. The drooping portions 75A and 75B are triangles with the ends of the bottom edges 65 as one side, and their shapes and areas are set according to the aforementioned welding conditions and forming paths of the deposited weld bead. The drooping portions 75A and 75B can have the same shape, or they can be set to different shapes. Alternatively, a pair of drooping portions 75A and 75B can be provided only at the end of either side of the bottom edge 65 of the trapezoidal weld bead models BMa and BMb.

[0127] By setting the weld bead models BMRs with drooping portions 75A and 75B as weld bead models for the stacking plan, the weld bead height of the deposited weld bead is less affected by the drooping caused by the deposited weld bead. Therefore, the manufactured object more closely resembles the shape according to the stacking plan. Furthermore, the drooping portions 75A and 75B are simple triangles, thereby reducing the computational burden.

[0128] Figure 16(A) and (B) are schematic diagrams showing the outer edge shape of the object W produced using a plan that takes into account the vertical weld bead models BMRs and the stacking of weld bead models BMRs. Figure 16 (B) is to make the filler material supply speed and welding speed relative to Figure 16 The result of case (A) is increased. Thus, in either case, it is possible to manufacture the model W in a shape close to the weld bead model of the stacked plan.

[0129] <Support for creating a display device using a layered design>

[0130] The above-described stacking scheme using various weld bead models, through repeated modeling and modification of the target shape, can make the shape of the object more closely approximate the target shape.

[0131] Figure 3 The model display device 200 shown, for example, enables the aforementioned Figure 10 (B) Figure 11 (B) Figure 14 or Figure 16 The shape of the weld bead model, as shown, is displayed on the display unit 53, allowing the operator to easily check the quality of the model or request model corrections. Furthermore, if model corrections are needed, the operator can input adjustment instructions from the input unit 51 to re-set the weld bead model.

[0132] Specifically, by Figure 16 The shapes of each weld bead model and the model W are displayed on the display unit 53, allowing for comparison and confirmation of sufficient similarity to the target shape. Furthermore, if the shape of the weld bead model is further altered by inputting adjustment instructions, the quality of the alteration can be visually confirmed. This allows for easy confirmation of the stacking plan, thus improving the workability of the stacking plan. If the model display device 200 is attached to the stacking modeling device 100, this confirmation can be easily performed, even just before modeling, further improving the workability of the stacking modeling process.

[0133] Thus, the present invention is not limited to the above-described embodiments. Combining the various structures of the embodiments with each other, as well as making changes and applications based on the description in the specification and well-known technologies by those skilled in the art, are also intended by the present invention and are included within the scope of the claimed protection.

[0134] As stated above, the following matters are disclosed in this specification.

[0135] (1) A method for creating a shaped object by stacking weld beads formed by melting and solidifying filler material onto a base, wherein...

[0136] The layered modeling method has the following characteristics:

[0137] The process of reading in the three-dimensional shape data of the object;

[0138] The process of dividing the shape of a three-dimensional model based on the three-dimensional shape data into multiple layers, and further dividing each layer into multiple weld bead models corresponding to the weld bead shape of the deposited weld bead; and

[0139] The process of forming the weld bead by repeatedly performing the process along the segmented weld bead model from the lower to the upper layers of the multiple layers, thereby stacking the weld bead, is described.

[0140] The weld bead model is trapezoidal in shape. In a cross-section perpendicular to the long side of the weld bead, the bottom edge of the base side is parallel to the top edge of the opposite side of the base. Furthermore, the pair of opposite sides of the weld bead model arranged in the same layer are not parallel to each other in the arrangement direction.

[0141] The process of dividing the weld bead model into the plurality of weld patterns includes the following steps:

[0142] Within the same layer, the weld bead model corresponding to the first formed weld bead and the weld bead model corresponding to the weld bead formed subsequently adjacent to it are arranged in a manner that they overlap with each other.

[0143] Using the vertex located at the end of the bottom edge of the weld bead model on the side furthest from the overlapping portion, one of the four vertices of the weld bead model formed later as the center, the other three vertices are rotated and moved respectively, thereby changing the shape of the weld bead model on the side formed later.

[0144] According to this layered modeling method, the shape of the weld bead model can be easily adjusted by simple calculations, such as rotating and moving the vertices of the trapezoidal weld bead model. Therefore, it is possible to create a model with a shape that more closely resembles the target shape.

[0145] (2) According to the layered modeling method described in (1), wherein,

[0146] The rotation angle that causes the other three vertices to rotate and move is set according to the welding conditions or the formation track of the weld bead.

[0147] According to this layered modeling method, the shape of the weld bead model can be set to a more appropriate shape based on the location of the weld bead and the layered pattern.

[0148] (3) According to the layered modeling method described in (1) or (2), wherein,

[0149] The rotation angle that causes the other three vertices to rotate and move is set differently for each of the vertices.

[0150] According to this layered modeling method, even if the weld bead is a complex shape that cannot be represented by a simple rotation of a trapezoid, the complex shape can be easily reproduced.

[0151] (4) The layering modeling method according to any one of (1) to (3), wherein,

[0152] The rotation angles that cause the other three vertices to rotate and move are set based on the pre-defined formulas.

[0153] According to this layered modeling method, by adjusting the coefficients in the calculation formula, the weld bead model can be made to more closely resemble the shape of the actual weld bead.

[0154] (5) According to the layered modeling method described in (4), wherein,

[0155] The formula is a linear or curvilinear relationship that uses the coordinate values ​​along the bottom edge of the weld bead model as variables.

[0156] According to this layered modeling method, the rotational movement amount can be set to correspond to the radius distance from a vertex that becomes the center of rotation.

[0157] (6) The layering modeling method according to any one of (1) to (5), wherein,

[0158] The weld bead model formed later on one side is replaced by a trapezoidal shape and set as a shape with 5 vertices bounded by the following points:

[0159] The vertex of the end of the weld bead model on the side of the bottom edge that is away from the overlapping portion;

[0160] A pair of vertices located at both ends of the upper side in the weld bead model formed later on one side;

[0161] The intersection of the side edge of the overlapping portion in the weld bead model formed later with the outer periphery of the weld bead model formed earlier; and

[0162] The vertex of the end of the previously formed weld bead model located on the overlapping side of the bottom edge.

[0163] According to this layered shaping method, even weld beads that are closer to parallelograms than trapezoids, such as weld beads formed adjacent to existing weld beads, can achieve good shape fitting.

[0164] (7) The layering modeling method according to any one of (1) to (5), wherein,

[0165] A drooping portion is provided at one or both ends of the bottom edge of the weld bead model located above the bottom layer, representing the molten filler material falling towards the lower layer.

[0166] According to this layered modeling method, by setting a drooping portion in the weld bead model, the weld bead height is less affected by the drooping caused by the weld bead. Therefore, the shape of the manufactured object can be made closer to the shape according to the layering plan.

[0167] (8) According to the layered modeling method described in (7), wherein,

[0168] The drooping portion is triangular in shape.

[0169] According to this layered modeling method, the shape of the drooping part is set as a simple triangle, which can reduce the computational burden.

[0170] (9) A layered molding apparatus, wherein a molten weld bead formed by melting and solidifying a filler material is layered on a base to create a molded object, wherein...

[0171] The stacked molding device includes:

[0172] The input unit reads in the three-dimensional shape data of the object;

[0173] The model setting unit divides the shape of the solid model based on the three-dimensional shape data into multiple layers, and further divides each layer into multiple weld bead models corresponding to the weld bead shape of the deposited weld bead; and

[0174] The molding section repeatedly performs the process of forming the weld beads along the segmented weld bead model from the lower layer to the upper layer of the multiple layers, thereby stacking the weld beads.

[0175] The weld bead model is trapezoidal in shape. In a cross-section perpendicular to the long side of the weld bead, the bottom edge of the base side is parallel to the top edge of the opposite side of the base. Furthermore, the pair of opposite sides of the weld bead model arranged in the same layer are not parallel to each other in the arrangement direction.

[0176] The model setting unit arranges the weld bead model corresponding to the first formed weld bead and the weld bead model corresponding to the subsequently formed weld bead adjacent to it in the same layer in such a way that they have overlapping portions.

[0177] The model setting unit takes the vertex located at the end of the bottom edge of the weld bead model on the side furthest from the overlapping portion, one of the four vertices of the weld bead model formed later, as the center, and rotates and moves the other three vertices respectively, thereby changing the shape of the weld bead model formed later.

[0178] According to this layered modeling device, the shape of the weld bead model can be easily adjusted by simple calculations, such as rotating and moving the vertices of the trapezoidal weld bead model. Therefore, it is possible to create a model with a shape that more closely resembles the target shape.

[0179] (10) The layered molding device according to (9), wherein,

[0180] The layered modeling device also includes a display unit that displays information about the weld pattern whose shape has been changed by the model setting unit.

[0181] According to this layered molding device, by displaying the shape of the weld bead model on the display unit, it is possible to easily confirm the shape that is close to the shape obtained by actually making the molded object before molding.

[0182] (11) A model display device, wherein,

[0183] The model display device includes:

[0184] The input unit receives information about the weld bead model set by the model setting unit of the stacked modeling apparatus described in (9); and

[0185] The display unit shows the information of the input weld model.

[0186] According to this model display device, by displaying the shape of the weld bead model on the display unit, it is easy for the operator to confirm the quality of the modeling or to urge corrections.

[0187] (12) The model display device according to (11), wherein,

[0188] The information indicating the adjustment of the weld bead model is input to the input unit.

[0189] The model display device includes a display data generation unit, which adjusts the weld bead model according to the input adjustment instruction information and outputs the adjusted display data of the weld bead model to the display unit.

[0190] The model display device can show the results of the operator's adjustments to the weld bead model, improving convenience.

[0191] This application is based on Japanese Patent Application No. 2020-206079, filed on December 11, 2020, the contents of which are incorporated herein by reference.

[0192] Explanation of reference numerals in the attached figures

[0193] 11 Styling Department

[0194] 13 Power Supply Section

[0195] 15 Controllers

[0196] 17 Welding torch

[0197] 19 Welding Robots

[0198] 21. Filler Material Supply Department

[0199] 25 Base Plate

[0200] 31 Input Section

[0201] 33 Model Setting Department

[0202] 35-Layer Project Department

[0203] 37 Storage Department

[0204] 39 Ministry of Communications

[0205] 41 Control Department

[0206] Display sections 43 and 47

[0207] 45 weld bead layers

[0208] 51 Input Section

[0209] 53 Display Department

[0210] 55 Display Data Generation Department

[0211] Pages 61 and 63

[0212] 65 bottom edge

[0213] 67 Above

[0214] 69, 71 Side

[0215] 73 Overlapping parts

[0216] 100-layered modeling installation

[0217] 200 Model Display Device

[0218] M Filler Material

[0219] PC external computer

[0220] BM0 Rectangular Weld Bead Model

[0221] BM trapezoidal weld bead model

[0222] BMR weld bead model

[0223] BMRs weld bead model

[0224] B weld bead

[0225] BL layer.

Claims

1. A method for creating a shaped object by stacking weld beads formed by melting and solidifying filler material onto a base, wherein, The layered modeling method has the following characteristics: The process of reading in the three-dimensional shape data of the object; The process of dividing the shape of a three-dimensional model based on the three-dimensional shape data into multiple layers, and further dividing each layer into multiple weld bead models corresponding to the weld bead shape of the weld bead; as well as The process of repeatedly forming the weld beads along the segmented weld bead model from the lower to the upper layers of the multiple layers, thereby stacking the weld beads, is described. The weld bead model is trapezoidal in shape. In a cross-section perpendicular to the long side of the weld bead, the bottom edge of the base side is parallel to the top edge of the opposite side of the base. Furthermore, the pair of opposite sides of the weld bead model arranged in the same layer are not parallel to each other in the arrangement direction. The process of dividing the weld bead model into the plurality of weld patterns includes the following steps: Within the same layer, the weld bead model corresponding to the first formed weld bead and the weld bead model corresponding to the weld bead formed subsequently adjacent to it are arranged in a manner that they overlap with each other. Using the vertex located at the end of the bottom edge of the weld bead model on the side furthest from the overlapping portion, one of the four vertices of the weld bead model formed later as the center, the other three vertices are rotated and moved respectively, thereby changing the shape of the weld bead model on the side formed later.

2. The layered modeling method according to claim 1, wherein, The rotation angle that causes the other three vertices to rotate and move is set according to the welding conditions or the formation track of the weld bead.

3. The layered modeling method according to claim 1, wherein, The rotation angle that causes the other three vertices to rotate and move is set differently for each of the vertices.

4. The layered modeling method according to claim 2, wherein, The rotation angle that causes the other three vertices to rotate and move is set differently for each of the vertices.

5. The layered modeling method according to claim 1, wherein, The rotation angles that cause the other three vertices to rotate and move are set based on the pre-defined formulas.

6. The layered modeling method according to claim 2, wherein, The rotation angles that cause the other three vertices to rotate and move are set based on the pre-defined formulas.

7. The layered modeling method according to claim 3, wherein, The rotation angles that cause the other three vertices to rotate and move are set based on the pre-defined formulas.

8. The layered modeling method according to claim 4, wherein, The rotation angles that cause the other three vertices to rotate and move are set based on the pre-defined formulas.

9. The layered modeling method according to claim 5, wherein, The formula is a linear or curvilinear relationship that uses the coordinate values ​​along the bottom edge of the weld bead model as variables.

10. The layered modeling method according to claim 6, wherein, The formula is a linear or curvilinear relationship that uses the coordinate values ​​along the bottom edge of the weld bead model as variables.

11. The layered modeling method according to claim 7, wherein, The formula is a linear or curvilinear relationship that uses the coordinate values ​​along the bottom edge of the weld bead model as variables.

12. The layered modeling method according to claim 8, wherein, The formula is a linear or curvilinear relationship that uses the coordinate values ​​along the bottom edge of the weld bead model as variables.

13. The layered modeling method according to any one of claims 1 to 12, wherein, A drooping portion is provided at one or both ends of the bottom edge of the weld bead model located above the bottom layer, representing the molten filler material falling towards the lower layer.

14. The layered modeling method according to claim 13, wherein, The drooping portion is triangular in shape.

15. A method for creating a shaped object by stacking weld beads formed by melting and solidifying filler material onto a base, wherein, The layered modeling method has the following characteristics: The process of reading in the three-dimensional shape data of the object; The process of dividing the shape of a three-dimensional model based on the three-dimensional shape data into multiple layers, and further dividing each layer into multiple weld bead models corresponding to the weld bead shape of the weld bead; as well as The process of repeatedly forming the weld beads along the segmented weld bead model from the lower to the upper layers of the multiple layers, thereby stacking the weld beads, is described. In the process of dividing the weld bead model into the plurality of weld patterns, Within the same layer, the weld bead model corresponding to the initially formed weld bead is trapezoidal in shape. In a cross-section perpendicular to the long side of the weld bead, the bottom edge of the base side is parallel to the top edge of the opposite side of the base. Furthermore, the pair of opposite sides of the weld bead model arranged in the same layer are not parallel to each other in the arrangement direction. Within the same layer, the weld bead model on the later-formed side is set as a shape with 5 vertices obtained by rotating and shifting the trapezoidal shape around the vertex of the end of the weld bead model on the side furthest from the bottom edge of the later-formed side, where the 5 vertices include: As the vertex of the center; A pair of vertices located at both ends of the upper side in the weld bead model formed later on one side; The intersection of the side edge of the first-formed weld bead model and the outer periphery of the first-formed weld bead model in the weld bead model formed later; and The vertex of the first-formed weld bead model located at the end of the side of the second-formed weld bead model on the bottom edge.

16. A layering molding apparatus for creating a molded object by layering weld beads formed by melting and solidifying filler material onto a base, wherein... The stacked molding device includes: The input unit reads in the three-dimensional shape data of the object; The model setting unit divides the shape of the solid model based on the three-dimensional shape data into multiple layers, and divides each layer into multiple weld bead models corresponding to the weld bead shape of the weld bead. as well as The molding section repeatedly performs the process of forming the weld beads along the segmented weld bead model from the lower layer to the upper layer of the multiple layers, thereby stacking the weld beads. The weld bead model is trapezoidal in shape. In a cross-section perpendicular to the long side of the weld bead, the bottom edge of the base side is parallel to the top edge of the opposite side of the base. Furthermore, the pair of opposite sides of the weld bead model arranged in the same layer are not parallel to each other in the arrangement direction. The model setting unit arranges the weld bead model corresponding to the first formed weld bead and the weld bead model corresponding to the subsequently formed weld bead adjacent to it in the same layer in such a way that they have overlapping portions. The model setting unit takes the vertex located at the end of the bottom edge of the weld bead model on the side furthest from the overlapping portion, one of the four vertices of the weld bead model formed later, as the center, and rotates and moves the other three vertices respectively, thereby changing the shape of the weld bead model formed later.

17. The layering molding apparatus according to claim 16, wherein, The layered modeling device also includes a display unit that displays information about the weld pattern whose shape has been changed by the model setting unit.

18. A model display device, wherein, The model display device includes: The input unit receives information about the weld bead model set by the model setting unit of the stacked modeling apparatus according to claim 16; and The display unit shows the information of the input weld model.

19. The model display device according to claim 18, wherein, The information indicating the adjustment of the weld bead model is input to the input unit. The model display device includes a display data generation unit, which adjusts the weld bead model according to the input adjustment instruction information and outputs the adjusted display data of the weld bead model to the display unit.

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