Method and device for correcting control information of additive manufacturing device, and program

Abstract

To provide a control information correction method of a laminate molding device, a control information correction device and program which can suppress deviation from a planned molding shape in a curved molding path.SOLUTION: A control information correction method of a laminate molding device comprises the steps of: acquiring molding plan information including a bead shape information of a bead on a molding path and along the molding path; calculating distribution of bead height deviation on a cross section orthogonal to the molding path in the bead formed in a longer direction of the molding path based on the molding plan information and the information of the bead shape; obtaining a torch inclined angle which discharges arc, when there is a higher portion deviated from a center of the bead width in the distribution of bead height deviation, in a direction for pushing back the deviated and higher portion into the center side of the bead width; and correcting control information created based on the molding plan information to form a bead at an attitude of the torch inclined by the torch inclined angle.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a control information correction method, a control information correction device, and a program for a layered manufacturing device that models a three-dimensional shape. [Background technology]

[0002] In recent years, there has been an increasing need for modeling using 3D printers as a means of production, and research and development is being conducted toward the practical application of modeling using metal materials. 3D printers for modeling metal materials use a heat source such as a laser, an electron beam, or even an arc to melt metal powder or metal wire, and create a model by layering the molten metal. As an example of such a modeling technique, Patent Document 1 discloses a method for forming a bead along a molding material, layering the bead while adjusting the shape of the bead that will form the model, and forming the model. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] China Patent Publication No. 110899905 Summary of the Invention [Problem to be solved by the invention]

[0004] When a bead is formed along a curved molding path, the smaller the radius of curvature of the molding path, the more significant the bias in the bead height distribution of the formed bead. For example, when a bead is formed along a curved molding path, the supply of material to form the bead is excessive in the region inside the curve and insufficient in the region outside the curve. As a result, the bead height distribution of the formed bead tends to be high on the inside of the curve and low on the outside of the curve. If no measures are taken to address this bias in the bead height distribution and the bead is formed under the same conditions as the rest of the curved area, this will cause bead sagging, insufficient penetration, etc., resulting in a large deviation from the planned molding shape.

[0005] Therefore, an object of the present invention is to provide a control information correction method, a control information correction device, and a program for an additive manufacturing apparatus that can suppress deviation from a planned modeling shape even in a curved modeling path. [Means for solving the problem]

[0006] The present invention comprises the following configurations. (1) A method for modifying control information for an additive manufacturing device that moves a processing point along a modeling path, adds a processing material molten by an arc emitted from a torch tip to a processing target surface at the processing point, forms a layer shape using a bead, and laminates the formed layer shape to form a three-dimensional shape, the method comprising the steps of: modifying control information for controlling bead formation along the modeling path by the additive manufacturing device, the method comprising the steps of: acquiring molding plan information including information on the molding path and the bead shape of the bead; calculating a bead height bias distribution in a cross section perpendicular to the manufacturing path, in a bead formed along a longitudinal direction of the manufacturing path, based on the manufacturing plan information and the bead shape information; When the bead height distribution includes a portion that is biased toward the center of the bead width and is high, a torch tilt angle is determined for emitting the arc in a direction that pushes back the biased portion toward the center of the bead width, correcting the control information created based on the modeling plan information so that a bead is formed in a posture in which the torch is tilted at the torch tilt angle; A method for correcting control information of an additive manufacturing device. (2) A control information correction device that corrects control information that controls an additive manufacturing device that forms a three-dimensional shape by a bead formed from a processing material melted by an arc emitted from a torch tip when the additive manufacturing device forms a bead along a modeling path, the control information correction device comprising: an information acquiring unit that acquires molding plan information including information on the molding path and a bead shape of the bead; a bias distribution calculation unit that calculates a bias distribution of bead heights in a cross section perpendicular to the molding path, in a bead formed along a longitudinal direction of the molding path, based on the molding plan information and information on the bead shape; a torch tilt angle setting unit that, when a portion that is biased and high from a bead width center exists in the biased distribution of the bead height, determines a torch tilt angle that causes the arc to be emitted in a direction that pushes back the biased and high portion toward the bead width center; a correction unit that corrects the control information created based on the modeling plan information so that a bead is formed in a posture in which the torch is tilted at the torch tilt angle; A control information modifying device comprising: (3) In an additive manufacturing device that moves a processing point along a modeling path, a processing material molten by an arc emitted from a torch tip is added to a processing target surface at the processing point to form a layer shape using a bead, and the formed layer shape is stacked to form a three-dimensional shape, the program being for modifying control information for controlling bead formation along the modeling path by the additive manufacturing device, On the computer, acquiring molding plan information including information on the molding path and the bead shape of the bead; calculating a bead height bias distribution in a cross section perpendicular to the manufacturing path, in a bead formed along a longitudinal direction of the manufacturing path, based on the manufacturing plan information and the bead shape information; a step of determining a torch tilt angle for emitting the arc in a direction to push back the unevenly elevated portion toward the bead width center when the unevenly elevated portion exists in the bead height distribution; a step of correcting the control information, which is created based on the modeling plan information, so that a bead is formed in a posture in which the torch is tilted at the torch tilt angle; A program for executing. Effect of the Invention

[0007] According to the present invention, deviation from the planned modeling shape can be suppressed even in a curved modeling path. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing the overall configuration of an additive manufacturing apparatus. [Diagram 2] FIG. 2 is a functional block diagram of the control information modifying device. [Diagram 3] FIG. 3 is a flowchart showing a procedure for modifying the control information. [Figure 4] FIG. 4 is an explanatory diagram showing an example of a bead model that takes into consideration overlap between adjacent beads. [Diagram 5] FIG. 5 is an explanatory diagram showing an example of a bead model that reproduces the shape of the weld metal dripping down to the lower layer side. [Figure 6] FIG. 6 is an explanatory diagram showing a state in which rectangular bead models are arranged along a linear path. [Figure 7] FIG. 7 is an explanatory diagram showing bead models arranged along a curved path. [Figure 8] FIG. 8 is an explanatory diagram showing the bead height distribution when a bead is formed along a curved path. [Figure 9] FIG. 9 is an explanatory diagram showing a cross section perpendicular to the path of the bead model shown in FIG. [Figure 10] FIG. 10 is a schematic explanatory diagram showing how bead models overlap when the radius of curvature of the path is less than half the bead width. [Figure 11] FIG. 11 is an explanatory diagram showing the overlapping portion between opposing bead models at (A), (B), and (C). [Figure 12] FIG. 12 is an explanatory diagram showing a cross section perpendicular to the path of the bead model shown in FIG. [Figure 13] FIG. 13 is an explanatory diagram showing the relationship between the uneven distribution of the height of the weld bead and the tilt angle of the torch. [Figure 14] FIG. 14 is an explanatory diagram showing a path in which the curvature direction changes along the welding proceeding direction. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The additive manufacturing device shown here moves a processing point along a modeling path based on a predetermined modeling plan, and forms a layer shape using a weld bead (bead) formed by adding a processing material melted by an arc emitted from the tip of a torch to a processing target surface of the processing point, and stacks the formed layer shapes to form a three-dimensional shape. The control information correction device corrects the control information created based on the modeling plan so as to suppress deviation from the planned modeling shape.

[0010] <Configuration of additive manufacturing device> An example of the configuration of an additive manufacturing device that operates based on the above control information will be described. The control information modification device modifies the control information to change the modeling operation of the additive manufacturing device.

[0011] 1 is a schematic diagram showing the overall configuration of an additive manufacturing apparatus. The additive manufacturing apparatus 100 includes a modeling unit 11 and a modeling control unit 13. The control information correction device 200 may be connected to the modeling control unit 13 to form a part of the additive manufacturing apparatus 100, or may be provided separately from the additive manufacturing apparatus 100 and connected to the modeling control unit 13 via a communication network or a storage medium.

[0012] The modeling unit 11 includes a manipulator 17, a filler metal supply unit 19, a manipulator control unit 21, and a heat source control unit .

[0013] The manipulator control unit 21 controls the manipulator 17 and the heat source control unit 23. A controller (not shown) is connected to the manipulator control unit 21, and any operation from the manipulator control unit 21 can be instructed by an operator via the controller.

[0014] The manipulator 17 is, for example, an articulated robot, and a torch 25 provided on the tip shaft is supported so that the filler material M can be continuously supplied. The torch 25 holds the filler material M in a state where it protrudes from the tip. The position and posture of the torch 25 can be set arbitrarily in three dimensions within the range of the degrees of freedom of the robot arm constituting the manipulator 17. The manipulator 17 is preferably one having six or more degrees of freedom, and is preferably one that can arbitrarily change the axial direction of the heat source at the tip. The manipulator 17 may be in various forms, such as a four- or more-axis articulated robot as shown in FIG. 1, or a robot equipped with angle adjustment mechanisms on two or more orthogonal axes.

[0015] The torch 25 has a shield nozzle (not shown), and a shielding gas is supplied from the shielding nozzle. The shielding gas blocks the atmosphere and prevents oxidation and nitridation of the molten metal during welding, thereby suppressing poor welding. The arc welding method used in this configuration may be either a consumable electrode type such as a shielded metal arc welding or a carbon dioxide gas arc welding, or a non-consumable electrode type such as a TIG (Tungsten Inert Gas) welding or a plasma arc welding, and is appropriately selected depending on the object to be molded. Here, gas metal arc welding is taken as an example for explanation. In the case of the consumable electrode type, a contact tip is disposed inside the shield nozzle, and a filler material M to which a current is supplied is held by the contact tip. The torch 25 generates an arc from the tip of the filler material M in a shielding gas atmosphere while holding the filler material M.

[0016] The filler metal supply unit 19 supplies the filler metal M toward the torch 25. The filler metal supply unit 19 includes a reel 19a on which the filler metal M is wound, and a pay-out mechanism 19b that pays out the filler metal M from the reel 19a. The filler metal M is fed to the torch 25 while being sent in the forward or reverse direction by the pay-out mechanism 19b as necessary. The pay-out mechanism 19b is not limited to a push type that is disposed on the filler metal supply unit 19 side and pushes out the filler metal M, but may be a pull type or a push-pull type that is disposed on a robot arm or the like.

[0017] The heat source control unit 23 is a welding power source that supplies power required for welding by the manipulator 17. The heat source control unit 23 adjusts the welding current and welding voltage supplied when forming a bead by melting and solidifying the filler metal M. In addition, the filler metal supply speed of the filler metal supply unit 19 is adjusted in conjunction with the welding conditions set by the heat source control unit 23, such as the welding current and welding voltage.

[0018] The heat source for melting the filler material M is not limited to the above-mentioned arc. For example, a heating method using an arc and a laser in combination, a heating method using plasma, a heating method using an electron beam or a laser, or other heat sources using other methods may be used. When heating with an electron beam or a laser, the amount of heat can be controlled more precisely, and the state of the weld bead to be formed can be more appropriately maintained, which contributes to further improving the quality of the laminated structure. The material of the filler material M is also not particularly limited, and the type of filler material M used may be different depending on the characteristics of the molded object Wk, such as mild steel, high-tensile steel, aluminum, aluminum alloy, nickel, or nickel-based alloy.

[0019] The forming control unit 13 controls the above-mentioned units in an integrated manner.

[0020] The additive manufacturing apparatus 100 having the above-mentioned configuration operates according to a modeling program created based on a modeling plan for the object Wk. The modeling program is composed of a large number of command codes, and is created based on an appropriate algorithm according to various conditions such as the shape, material, and heat input of the object Wk. When the torch 25 is moved and the supplied filler material M is melted and solidified according to this modeling program, a linear weld bead B, which is a molten solidified body of the filler material M, is formed on the base 27. That is, the manipulator control unit 21 drives the manipulator 17 and the heat source control unit 23 based on a predetermined program provided from the modeling control unit 13. The manipulator 17 moves the torch 25 while melting the filler material M with an arc, according to a command from the manipulator control unit 21, to form the weld bead B. In this way, the weld beads B are formed and stacked sequentially, thereby obtaining a model Wk having a desired shape.

[0021] <Configuration of the control information modification device> 2 is a functional block diagram of the control information modifying device 200. The control information modifying device 200 includes an information acquiring unit 31, a biased distribution calculating unit 33, a torch tilt angle setting unit 35, and a modifying unit 37. Details of each unit of the control information modifying device 200 will be described later, but the general functions are as follows.

[0022] The information acquisition unit 31 acquires the shaping plan information including the shaping path and information on the bead shape of the weld bead formed along the shaping path. The bias distribution calculation unit 33 calculates the bias distribution of the bead height in a cross section perpendicular to the shaping path in the bead formed along the longitudinal direction of the shaping path based on the shaping plan information and the bead shape information. The torch tilt angle setting unit 35 obtains the bias distribution of the bead height in a cross section in the bead width direction (direction perpendicular to the longitudinal direction of the shaping path) and obtains the torch tilt angle at which the arc is emitted according to the bias distribution of the bead height. The correction unit 37 corrects the control information created based on the shaping plan information so that the bead is formed in a posture in which the torch is tilted at the torch tilt angle.

[0023] The control information input to the control information correction device 200 and corrected is output to, for example, the printing control unit 13 shown in Fig. 1. The printing control unit 13 corrects the printing plan to change the torch posture for a specific point in the middle of the printing path, i.e., a point where a new torch inclination angle is set (a portion of a curved printing path), and creates or updates the printing program. Then, the printing control unit 13 controls the drive of the printing unit 11 based on the new printing program, thereby making it possible to suppress deviation from the planned printing shape even in a curved printing path.

[0024] The control information modifying device 200 is configured by hardware using an information processing device such as a PC (Personal Computer). Each function of the control information modifying device 200 is realized by a control unit (not shown) reading a program having a specific function stored in a storage device (not shown) and executing the program. Examples of the control unit include a processor such as a CPU (Central Processing Unit) or an MPU (Micro Processor Unit), or a dedicated circuit. Examples of the storage device include a memory such as a RAM (Random Access Memory) which is a volatile storage area, a ROM (Read Only Memory) which is a non-volatile storage area, and a storage such as a HDD (Hard Disk Drive) or an SSD (Solid State Drive).

[0025] In addition to the above-described configuration, the control information modifying device 200 may be configured by another computer that is connected to the forming control unit 13 from a remote location via a network or the like, as described above.

[0026] Next, a procedure for modifying control information by the control information modifying device 200 will be described in detail together with the configuration of each unit shown in FIG. 3 is a flowchart showing a procedure for correcting the control information. A modeling path for forming a weld bead for forming the model Wk and modeling plan information on the bead shape of the weld bead to be formed are obtained (S1). The modeling path may be calculated by a known method, for example, by slicing the shape of the model, such as CAD data, to a predetermined thickness and applying a bead model that imitates the shape of the weld bead to the sliced ​​layer shape. Alternatively, modeling plan information that has been generated and stored in advance may be read.

[0027] Information on the printing path (hereinafter also referred to as path) included in the loaded printing plan information includes, for example, coordinate information (X, Y, Z) of points included in the path, the pitch d between adjacent paths, the thickness of the sliced ​​layers (layer spacing) h, the stacking order of each path, etc.

[0028] Meanwhile, the acquired bead shape information includes shape information such as a bead model, a bead width, a bead height, etc. By setting a bead model along a set path, it is possible to estimate, from a linear path, a bead shape when a weld bead is formed along a movement trajectory of a torch, which is a target position for forming the weld bead.

[0029] FIG. 4 is an explanatory diagram showing an example of a bead model considering the overlap between adjacent beads. Here, the shapes of three bead models in a cross section perpendicular to the longitudinal direction of the weld bead are shown. In each bead model, the cross-sectional shape of the bead model BMa of the reference pass PS1 is a trapezoid, the bead model BMb of the pass PS2 is provided adjacent to the bead model BMa, and the bead model BMc of the pass PS3 is provided adjacent to the bead model BMb. The bead models BMb and BMc are partially overlapped with the model arranged on the left side of FIG. 4. Specifically, the bead models BMb and BMc are basically trapezoidal in shape like the bead model BMa, and are rotated clockwise by a predetermined angle around one end of the base of the trapezoid opposite to the bead model BMa while maintaining the cross-sectional shape as it is, thereby inclining the base of the trapezoid. The area where the bead model BMb overlaps with the bead model BMa is defined as the area of ​​the bead model BMa, and the area below the bead model BMb that is not included in the bead model BMa is included in the area of ​​the bead model BMb. Similarly, the area where the bead model BMc overlaps with the bead model BMb is defined as the area of ​​the bead model BMb, and the area below the bead model BMc that is not included in the bead model BMb is included in the area of ​​the bead model BMc.

[0030] As a result, the shape of the bead model BMb becomes a polygon (pentagon) close to one of the hypotenuses of the bead model BMa, and the shape of the bead model BMc becomes a polygon (pentagon) close to one of the hypotenuses of the bead model BMb. In this way, each of the bead models BMa, BMb, and BMc has a shape that more closely resembles the cross-sectional shape of an actual weld bead.

[0031] FIG. 5 is an explanatory diagram showing an example of a bead model that reproduces the shape of a weld metal drooping to the lower layer side. Here, the shape of the bead model in a cross section perpendicular to the longitudinal direction of the weld bead is shown. Among the bead model BM1 having a trapezoidal cross section laminated on the base 27 and the bead models BM2, BM3, . . . , BMn (n is the number of layers) above the bead model BM1, the trapezoidal bead models BM2, BM3, . . . , BMn of the upper layers have drooping parts 43a, 43b added to both ends of the base 41. The cross-sectional shape of the drooping parts 43a, 43b is a triangle with the end of the base 41 as one side, and the shape and area are set according to the welding conditions and trajectory information (path) of the weld bead described above. The drooping parts 43a and 43b may be the same shape or different shapes. Furthermore, the hanging portions 43a, 43b may be provided at only one end of the base side 41, other than at both ends of the base side 41 of the trapezoidal bead model.

[0032] By setting the bead models BM2, BM3, ..., BMn with the sagging parts 43a, 43b as the bead models for the modeling plan, the bead height of the weld bead is affected by the sagging of molten metal that occurs in the weld bead. This makes it easier to match the calculated outline of the weld bead with the actual shape even under conditions where the molten metal of the weld bead is likely to sag, such as in an overhanging part.

[0033] The shape of the bead model can also be determined according to the welding conditions, such as the welding current, welding voltage, torch movement speed (rod running speed), and filler metal feed speed.

[0034] For example, bead height L H is calculated from equation (1), and the bead width L W can also be calculated from equation (2).

[0035]

number

[0036] T s: Torch movement speed W f :Filler feed rate C1~C6: Coefficients D1 to D6: Coefficients

[0037] The shape of the bead model may be determined by searching for a model shape that is closest to the set welding conditions from a database that stores the welding conditions in association with parameters such as the weld cross-sectional area, the bead height, the bead width, etc. Alternatively, an approximation formula may be created based on the database, and the model shape may be determined using the approximation formula.

[0038] As described above, the bead model is preferably one that reproduces the phenomenon that occurs when welding beads are actually laminated, such as a model that takes into account the overlap of adjacent beads, a model that reproduces the shape of the beads sagging to the lower layer, etc. In addition, the bead width and bead height may be related to welding conditions such as the welding speed and the feed speed.

[0039] Next, the bias distribution calculation unit 33 calculates the bias distribution of the bead height from the acquired information of the molding plan (information of the molding path and the bead shape) by using a model formula (S2). In the following description, a simple rectangular bead model is used to simplify the geometric calculation of the area, etc.

[0040] Fig. 6 is an explanatory diagram showing rectangular bead models BM arranged along a linear path PS. The bead width of this bead model BM is w, and the bead height is h. When the path PS is linear, multiple bead models BM are sequentially arranged along the path PS, thereby enabling uniform bead formation along the path PS as planned. However, when the path PS is curved, the greater the curvature of the path PS (the smaller the radius of curvature), the greater the overlaps and gaps between the bead models lined up along the path PS.

[0041] 7 is an explanatory diagram showing bead models BM arranged along a curved path PS. In this case, the bead models BM have overlapping portions 45 where adjacent bead models BM overlap each other on the radially inner side (called the curved inner side) of the path PS with a curvature radius R, and gaps 47 are formed between the bead models BM on the radially outer side (called the curved outer side) of the path PS. Therefore, when forming a weld bead along the path PS, the deposition amount (supply amount of molten filler metal M) required for the overlapping portion 45 to exist is smaller on the curved inner side of the bead model BM than the path PS. On the other hand, the deposition amount needs to be increased on the curved outer side of the path PS to fill the gaps 47 and form a continuous weld bead.

[0042] Figure 8 is an explanatory diagram showing the bead height distribution when a bead is formed along a curved pass PS. In reality, the distribution of bead heights in a cross section perpendicular to the longitudinal direction of pass PS does not have a symmetrical shape centered on the central position P0 of the bead width w as shown by the dashed line in the weld bead formed along pass PS. On the inside of the curve of pass PS, the amount of deposition is excessive, and the bead height increases. On the outside of the curve, the amount of deposition is insufficient, and the bead height decreases. As a result, the weld bead height distribution is such that the maximum height is biased toward the inside of the curve as shown by the solid line.

[0043] This type of bead height bias distribution can be quantitatively calculated using the model formula shown below. When the radius of curvature R of pass PS is equal to or greater than half the bead width w (R≧w / 2), the deposition amount WAin required for the area on the inside of the curve of pass PS can be expressed by formula (3). Additionally, the deposition amount WAout required for the outside of the curve can be expressed by formula (4). The deposition amount generated by operating the torch is equal on the outside and inside of the curve of pass PS and can be expressed by formula (5), so essentially the layer height hin on the inside of the curve and the layer height hout on the outside of the curve can be expressed by formula (6).

[0044]

number

[0045] FIG. 9 is an explanatory diagram showing a cross-section orthogonal to the path PS of the bead model shown in FIG. 7. The central position P0 between one end P1 and the other end P2 of the bead width w is the central position of the path PS. The left side (P1 side) of the central position P0 in FIG. 9 is the inner side of the curve, and the right side (P2 side) is the outer side of the curve. The outer side of the curve of the bead model BM has a bead height hout higher than the original bead height h, and the inner side of the curve has a bead height hin lower than the original bead height h.

[0046] Let line Ls connect the bead width center position Mout at the bead height hout in the outer curved region of the bead model and the bead width center position Min at the bead height hin in the inner curved region. The inclination angle θ of this line Ls from the horizontal plane can be estimated from Equation (8) derived from Equation (7) of the difference between the inner and outer bead heights (hin - hout). In this way, the welding amount Ain on the inner side of the curve is larger than the welding amount Aout on the outer side of the curve.

[0047]

Equation

[0048] Note that the descriptions by Equations (5) to (8) about the bias of the bead height distribution are applied to a simple geometric figure (arc) of the bead shape. Therefore, not limited to the above method, a model curve simulating the weld bead may be prepared and fitted to the curve. The final bias distribution of the bead height may be represented by the height difference of Equation (7) or the inclination angle θ specified by Equation (8). Note that the radius of curvature of the path PS does not necessarily need to approximate the path PS as circular, and the radius of curvature R of the arc when a part of the path PS is approximated as an arc may be used.

[0049] Also, when the radius of curvature R is less than half of the bead width w (R < w / 2), the following occurs. 10 is a schematic explanatory diagram showing the overlapping of bead models BM when the radius of curvature R of the path is less than half the bead width w. When the radius of curvature R of the path PS is small, the overlapping portions 45 of the overlapping portions 45 and the gap portions 47 between adjacent bead models BM overlap in multiple places.

[0050] 11 is an explanatory diagram showing an overlapping portion 45 between opposing bead models BM in (A), (B), and (C). The overlapping portion 45 is a multi-layered overlap between adjacent bead models and between opposing bead models. In other words, overlapping occurs not only in front of and behind the traveling direction of the path PS of the bead model BM, but also in the bead width direction perpendicular to the traveling direction.

[0051] The bead height bias distribution in this case can be calculated by the same procedure as in the above-mentioned case where the curvature radius R of the path PS is equal to or greater than half the bead width w (R≧w / 2). Fig. 12 is an explanatory diagram showing a cross section perpendicular to pass PS of the bead model shown in Fig. 10. The deposition amount WAin required for the area on the inside of the curve of pass PS can be expressed by equation (9), and the deposition amount WAout required for the outside of the curve can be expressed by equation (10). In addition, the deposition amount generated by the operation of the torch is equal on the outside and inside of the curve of pass PS and can be expressed by equation (5), so the layer height hin on the inside of the curve and the layer height hout on the outside of the curve can essentially be expressed by equation (11).

[0052]

number

[0053] Also, let Ls be the line connecting the bead width center position Mout at bead height hout in the outer curved region of the bead model and the bead width center position Min at 1 / 2 the radius of curvature R (the distance between P0 and P3) at bead height hin in the inner curved region. The inclination angle θ of this line Ls from the horizontal plane can be estimated from equation (13) which is derived from equation (12) for the difference between the inner and outer bead heights (hin-hout). In this way, the deposition amount Ain on the inner curve is greater than the deposition amount Aout on the outer curve.

[0054]

number

[0055] Next, based on the bead height bias distribution obtained by the bias distribution calculation unit 33 as described above, the torch tilt angle setting unit 35 sets the tilt angle of the torch (S3). Fig. 13 is an explanatory diagram showing the relationship between the bias distribution of the height of the weld bead and the tilt angle of the torch 25. When the bias distribution of the height of the bead is such that the maximum height position is biased toward the inside of the curve from the pass center in a cross section perpendicular to the longitudinal direction of the pass PS, it is advisable to tilt the torch 25 at a predetermined angle (torch tilt angle φ) from the vertical direction at the pass center to the inside of the curve in the cross section. When an arc is released from the tip of the torch 25 in this state, the arc pressure Park acts in a direction from the inside of the curve to the outside of the curve. This makes it possible to correct the bias of the weld metal to a non-biased distribution as shown by the dashed line in Fig. 13.

[0056] The greater the torch tilt angle φ is from the vertical direction, the greater the arc pressure Park acting in the lateral (horizontal) direction. Therefore, the greater the degree of deviation in the bead height, the greater the torch tilt angle φ should be.

[0057] When the torch 25 is tilted forward in the welding direction to provide a sweep back angle, the bead width tends to be narrow and the bead height tends to be high. On the other hand, when the torch is tilted backward in the welding direction to provide a sweep back angle, the opposite tendency to when a sweep back angle is provided tends to occur. Therefore, the torch tilt angle φ may be adjusted according to the sweep back angle or the sweep back angle. Specifically, the values ​​of the bead height and the bead width may be set to the values ​​during the forward or backward movement, and calculations may be performed according to the above-mentioned formulas. The torch tilt angle φ may also be set regardless of the sweep back angle or the sweep back angle.

[0058] The relationship between the deviation in bead height and the torch tilt angle φ may be experimentally or analytically determined, a database in which the relationship is stored as a table or an arithmetic expression may be prepared, and the torch tilt angle φ may be appropriately referenced to determine the torch tilt angle φ. Alternatively, the relationship between the deviation in bead height and the torch tilt angle φ may be modeled by machine learning, and the torch tilt angle φ may be determined using this model.

[0059] The above-mentioned path PS is a route that curves in a fixed direction with a fixed radius of curvature, but the shape of the path changes depending on the object. FIG. 14 is an explanatory diagram showing a path whose curvature direction changes along the welding advance direction. When the path PS has multiple inflection points and undulations, the above-mentioned inside curvature and outside curvature are switched along the welding advance direction. Therefore, when determining the bead height bias distribution, in order to accurately determine the curvature radius R of the curvature of the path PS, it is necessary to accurately define the inside curvature and the outside curvature. Therefore, basically, using an arbitrary point on the path PS as a reference, the side where a curvature circle 49 with a curvature radius approximating the path PS that passes through the point exists is defined as the inside curvature, and the side where the curvature circle 49 does not exist is defined as the outside curvature.

[0060] Next, the torch tilt angle φ determined by the above procedure is reflected in the control information of the additive manufacturing apparatus 100 (S4). When the additive manufacturing apparatus 100 is a manipulator 17 equipped with a torch 25 at the tip axis of a robot arm as shown in Fig. 1, control information is generated to set the attitude of the torch 25 to a set attitude, i.e., the attitude of the robot arm corresponding to this torch attitude.

[0061] Specifically, the correction unit 37 creates or corrects the modeling plan (modeling program) that is created based on the modeling plan information acquired by the information acquisition unit 31 and sets the operation of the manipulator 17 in the above-mentioned torch posture. Based on the created or corrected modeling plan, the modeling program is created or updated. Then, the modeling control unit 13 drives and controls the modeling unit 11 based on the newly created modeling program, thereby making it possible to suppress deviation from the planned modeling shape even in a curved modeling path.

[0062] In generating the above control information, known means may be adopted. For example, the relationship between the torch posture and each joint angle of the manipulator may be stored in advance, and the control information may be generated based on this relationship.

[0063] Also, when the relationship between the radius of curvature R and the bead width w is R < w / 2, if the overlap between bead models is not considered, excessive welding will be performed with respect to the required welding amount. Therefore, at the site on the path where R < w / 2, it is necessary to correct by reducing the welding amount set in the shaping plan.

[0064] In the case of the path PS along the circumference of a semi-circle shown in Fig. 7, the welding amount set in the shaping plan is hwπR obtained by multiplying the bead cross-sectional area by the path length (πR). However, as shown in Equation (14), the total required welding amount on the inner and outer sides of the curve is smaller than the set welding amount hwπR.

[0065] Therefore, the shaping plan is corrected so that the welding amount does not become excessive. Here, let the diameter of the filler metal M according to the shaping plan before correction be d wire , the welding speed be V weld 0 , and the filler metal supply speed be V wire 0 , and let the welding speed of the shaping plan after correction be V weld 1 , and the filler metal supply speed be V wire 1 . Since the bead cross-sectional area is constant before and after correction, the bead cross-sectional area A B0 shown in Equation (15) before correction is equal to the bead cross-sectional area A B1 shown in Equation (16) after correction.

[0066]

Equation

[0067] From this relationship, assuming that the diameter of the filler metal M is constant and adjusting the welding speed, the welding speed ratio (V weld 1 / V weld 0 ) is Equation (17). Also, assuming that the diameter of the filler metal M is constant and adjusting the feeding speed of the filler metal M, the feeding speed ratio (Vwire 1 / V wire 0 ) becomes Equation (18).

[0068] [Number]

[0069] As described above, by changing the torch posture, welding speed, and filler material supply speed, a shaping plan can be created to form the curved path PS with an appropriate welding amount. For example, when the relationship between the radius of curvature R of the path PS and the bead width w is R ≧ w / 2, the torch tilt φ is changed according to the tilt angle θ shown in Equation (8). Also, when R < w / 2, since the welding amount becomes even more excessive, in addition to changing the torch angle, at least one of the welding speed and the filler material supply speed is changed. As a result, when the calculated bead shape deviates from the center of the bead width in the curved shaping path, the torch is tilted at the calculated tilt angle φ to generate an arc, and the shaping plan can be corrected to make the shape of the weld bead less likely to deviate from the center of the bead width. As a result, deviation from the planned shaping shape can be suppressed. Also, since the deviation distribution of the height of the weld bead can be corrected at the shaping planning stage, complicated control such as separately feedback-controlling control information can be made unnecessary.

[0070] The present invention is not limited to the above-described embodiments, and it is also contemplated by the present invention that those skilled in the art can make changes and applications based on combining each configuration of the embodiments with each other, as well as the description in the specification and well-known techniques, and such are included in the scope for which protection is sought.

[0071] As described above, the following matters are disclosed in this specification. (1) In a laminating shaping apparatus that forms a layer shape using a bead formed by adding a processing material melted by an arc emitted from the tip of a torch while moving a processing point along a shaping path to a processing target surface of the processing point, and laminates the formed layer shape to shape a three-dimensional shape, a method for correcting control information for controlling bead formation along the shaping path by the laminating shaping apparatus, wherein acquiring molding plan information including information on the molding path and the bead shape of the bead; calculating a bead height bias distribution in a cross section perpendicular to the manufacturing path, in a bead formed along a longitudinal direction of the manufacturing path, based on the manufacturing plan information and the bead shape information; When the bead height distribution includes a portion that is biased toward the center of the bead width and is high, a torch tilt angle is determined for emitting the arc in a direction that pushes back the biased portion toward the center of the bead width, correcting the control information created based on the modeling plan information so that a bead is formed in a posture in which the torch is tilted at the torch tilt angle; A method for correcting control information of an additive manufacturing device. According to this method of correcting control information for an additive manufacturing device, if the shape of the bead deviates from the center of the bead width, the torch is tilted to generate an arc, and the manufacturing plan is corrected to make the shape of the bead less likely to deviate from the center of the bead width, thereby preventing deviation from the planned manufacturing shape.

[0072] (2) The control information correction method for an additive manufacturing device described in (1), wherein the torch inclination angle is an inclination angle of a torch tip axis from a bead height direction of the bead in a plane perpendicular to the longitudinal direction of the manufacturing path. According to this method for correcting control information for an additive manufacturing device, the direction in which the arc is generated can be changed by tilting the tip axis of the torch, and the direction in which the arc pressure acts can be freely changed.

[0073] (3) The control information correction method for an additive manufacturing device described in (1), wherein the bead height bias distribution is calculated using a model formula based on a curvature of the manufacturing path and a bead width of the bead. According to this method for correcting control information for an additive manufacturing device, the result of calculating the bead height bias distribution using a model formula according to the curvature of the modeling path can be propagated to the control information at the planning stage, eliminating the need for separate feedback control or the like.

[0074] (4) A method for correcting control information for an additive manufacturing device according to (3), further comprising continuously changing a tilt direction of the torch depending on whether a curvature corresponding to a point on the path of the modeling path is positive or negative. According to this method for correcting control information for an additive manufacturing device, even when the inner and outer curvatures switch along the path, the torch inclination angle can be adjusted while distinguishing between the inner and outer curvatures at each position on the path.

[0075] (5) A method for correcting control information for an additive manufacturing device described in (3), in which a bead height bias distribution is calculated using different model equations when the radius of curvature of the manufacturing path is smaller than half the bead width and when the radius of curvature of the manufacturing path is equal to or greater than half the bead width. According to this method for correcting control information for an additive manufacturing device, since the bead height bias distribution differs depending on the relationship between the radius of curvature and the bead width, by using different model equations for each case, the bead height bias distribution can be more accurately identified.

[0076] (6) A control information correction method for an additive manufacturing device described in any one of (3) to (5), in which, when the radius of curvature of the manufacturing path is smaller than half the bead width, the supply of the processing material to the bead formed along the manufacturing path is corrected in accordance with the difference between the volume on the inner side of the path and the volume on the outer side of the path according to the curvature of the manufacturing path, in addition to being corrected in accordance with the difference between the volume of an overlapping area where the beads overlap due to the approach of the manufacturing paths and the volume of a non-overlapping area. According to this method for correcting control information for an additive manufacturing device, it is possible to prevent the bead from being locally excessively piled and deviating from the planned shape.

[0077] (7) A control information correction device that corrects control information that controls an additive manufacturing device that forms a three-dimensional shape by a bead formed from a processing material melted by an arc emitted from a torch tip when the additive manufacturing device forms a bead along a modeling path, the control information correction device comprising: an information acquiring unit that acquires molding plan information including information on the molding path and a bead shape of the bead; a bias distribution calculation unit that calculates a bias distribution of bead heights in a cross section perpendicular to the molding path, in a bead formed along a longitudinal direction of the molding path, based on the molding plan information and information on the bead shape; a torch tilt angle setting unit that, when a portion that is biased and high from a bead width center exists in the biased distribution of the bead height, determines a torch tilt angle that causes the arc to be emitted in a direction that pushes back the biased and high portion toward the bead width center; a correction unit that corrects the control information created based on the modeling plan information so that a bead is formed in a posture in which the torch is tilted at the torch tilt angle; A control information modifying device comprising: According to this control information correction device, if the shape of the bead deviates from the center of the bead width, the torch is tilted to generate an arc, and the molding plan is corrected to make the shape of the bead less likely to deviate from the center of the bead width, thereby preventing deviation from the planned molding shape.

[0078] (8) In an additive manufacturing device that moves a processing point along a modeling path, a processing material molten by an arc emitted from a torch tip is added to a processing target surface at the processing point to form a layer shape using a bead, and the formed layer shape is stacked to form a three-dimensional shape, the program comprising: a program for modifying control information for controlling bead formation along the modeling path by the additive manufacturing device, the program comprising: On the computer, acquiring molding plan information including information on the molding path and the bead shape of the bead; calculating a bead height bias distribution in a cross section perpendicular to the manufacturing path, in a bead formed along a longitudinal direction of the manufacturing path, based on the manufacturing plan information and the bead shape information; a step of determining a torch tilt angle for emitting the arc in a direction to push back the unevenly elevated portion toward the bead width center when the unevenly elevated portion exists in the bead height distribution; a step of correcting the control information, which is created based on the modeling plan information, so that a bead is formed in a posture in which the torch is tilted at the torch tilt angle; A program for executing the above. According to this program, if the shape of the bead deviates from the center of the bead width, the torch is tilted to generate an arc, and the molding plan is modified to make the bead shape less likely to deviate from the center of the bead width, thereby preventing deviation from the planned molding shape. [Explanation of symbols]

[0079] 11 Modeling Department 13 Modeling control section 17 Manipulator 19 Filler metal supply section 19a Reel 19b Payout mechanism 21 Manipulator control section 23 Heat source control unit 25 Torch 27 Base 31 Information Acquisition Department 33 Bias distribution calculation unit 35 Torch tilt angle setting section 37 Correction section 41 Bottom 43a, 43b Hanging part 45 Overlap 47 Gap 49 Curvature Circle 100 Additive manufacturing equipment 200 Control information modification device B Weld bead (bead) BM, BM1, BM2, BM3, BMa, BMb, BMc bead models PS Pass R radius of curvature H Bead height w Bead width M filler metal Wk Sculpture φ Torch tilt angle

Claims

1. A method for modifying control information for an additive manufacturing device that modifies control information for controlling bead formation along the manufacturing path by the additive manufacturing device, the method comprising the steps of: moving a processing point along a manufacturing path, adding a processing material molten by an arc emitted from a torch tip to a processing target surface at the processing point, forming a layer shape using a bead, and stacking the formed layer shapes to manufacture a three-dimensional shape; acquiring molding plan information including information on the molding path and the bead shape of the bead; calculating a bias distribution of bead heights in a cross section perpendicular to the shaping path, in a bead formed along a longitudinal direction of the shaping path based on the shaping plan information and the bead shape information, by a model formula based on a curvature of the shaping path and a bead width of the bead; When the bead height distribution includes a portion that is biased toward the center of the bead width and is high, a torch tilt angle is determined for emitting the arc in a direction that pushes back the biased portion toward the center of the bead width, correcting the control information created based on the modeling plan information so that a bead is formed in a posture in which the torch is tilted at the torch tilt angle; A method for correcting control information of an additive manufacturing device.

2. The torch inclination angle is an inclination angle of a torch tip axis from a bead height direction of the bead in a plane perpendicular to the longitudinal direction of the molding path. The method for correcting control information of an additive manufacturing apparatus according to claim 1 .

3. The tilt direction of the torch is continuously changed according to the positive or negative curvature corresponding to the point on the path of the modeling path. The method for correcting control information of an additive manufacturing apparatus according to claim 1 .

4. determining a bias distribution of the bead height using different model formulas in a case where the radius of curvature of the shaping path is smaller than half the bead width and in a case where the radius of curvature of the shaping path is equal to or larger than half the bead width; The method for correcting control information of an additive manufacturing apparatus according to claim 1 .

5. When the radius of curvature of the shaping path is smaller than half the width of the bead, the supply of the processing material to the bead formed along the shaping path is corrected according to the difference between the volume on the inner periphery side of the path and the volume on the outer periphery side of the path according to the curvature of the shaping path, and also according to the difference between the volume of an overlapping region where the beads overlap each other due to the approach of the shaping paths and the volume of a non-overlapping region. A method for correcting control information of an additive manufacturing apparatus according to claim 1 .

6. A control information correction device that corrects control information for controlling an additive manufacturing device that forms a three-dimensional shape by a bead formed of a processing material melted by an arc emitted from a torch tip when the additive manufacturing device forms a bead along a modeling path, the control information correction device comprising: an information acquiring unit that acquires molding plan information including information on the molding path and a bead shape of the bead; a bias distribution calculation unit that calculates a bias distribution of bead heights in a cross section perpendicular to the molding path, in a bead formed along a longitudinal direction of the molding path based on the molding plan information and information on the bead shape, by a model formula based on a curvature of the molding path and a bead width of the bead; a torch tilt angle setting unit that, when a portion that is biased and high from a bead width center exists in the biased distribution of the bead height, determines a torch tilt angle that causes the arc to be emitted in a direction that pushes back the biased and high portion toward the bead width center; a correction unit that corrects the control information created based on the modeling plan information so that a bead is formed in a posture in which the torch is tilted at the torch tilt angle; A control information modifying device comprising:

7. A layered manufacturing device that forms a layer shape using a bead formed by adding a processing material molten by an arc emitted from a torch tip to a processing target surface of a processing point while moving the processing point along a modeling path, and stacks the formed layer shapes to form a three-dimensional shape, comprising: a program for modifying control information for controlling bead formation along the modeling path by the layered manufacturing device, On the computer, acquiring molding plan information including information on the molding path and the bead shape of the bead; a step of calculating a bias distribution of bead heights in a cross section perpendicular to the shaping path, in a bead formed along a longitudinal direction of the shaping path based on the shaping plan information and the bead shape information, by a model formula based on a curvature of the shaping path and a bead width of the bead; a step of determining a torch tilt angle for emitting the arc in a direction to push back the unevenly elevated portion toward the bead width center when the unevenly elevated portion exists in the bead height distribution; a step of correcting the control information, which is created based on the modeling plan information, so that a bead is formed in a posture in which the torch is tilted at the torch tilt angle; A program for executing the above.

Images