Additive manufacturing device and additive manufacturing method

Abstract

This additive manufacturing device comprises: a beam heat source supply unit that outputs a beam for melting a manufacturing material; a current supply unit that causes a current to flow through the manufacturing material; a manufacturing material supply unit (16) that supplies the manufacturing material to a workpiece; and a bead shape control unit that acquires bead state information, which is information indicating the state of an underlying bead where the manufacturing material has melted and solidified on the workpiece due to Joule heat caused by the beam irradiation and the energization, and controls at least one from among an output value of the beam, a current value during energization, and a manufacturing material supply rate in accordance with the bead state information such that a new bead formed on top of the underlying bead has a determined height and width.

Description

Additive manufacturing device and additive manufacturing method

[0001] The present disclosure relates to an additive manufacturing apparatus and an additive manufacturing method for manufacturing a three-dimensional object.

[0002] Metal additive manufacturing includes Powder Bed Fusion (PBF), in which metal powder is laid out and irradiated with a laser beam at the area to be shaped, melting and solidifying it, and Directed Energy Deposition (DED), in which focused thermal energy is used to melt, bond, and deposit materials. One DED method involves feeding a filler wire to the workpiece and locally melting the tip of the wire with a laser beam to form a bead.

[0003] Patent Literature 1 describes an additive manufacturing device that manufactures a shaped object by stacking beads that are solidified products of molten filler metal. The additive manufacturing device described in Patent Literature 1 includes a supply unit that supplies filler metal to a workpiece, a beam source that outputs a beam that melts the supplied filler metal, and a position calculation unit that calculates the tip position of the filler metal, which is the position at which the temperature of the filler metal reaches the melting point of the filler metal due to irradiation with the beam, based on the supply speed of the filler metal supplied to the workpiece and the beam output from the beam source.

[0004] International Publication No. 2022 / 107196

[0005] When adjusting the filler metal feed rate to maintain a constant bead height, it is necessary to also adjust the beam power to ensure sufficient wire melting. The magnitude of the beam power is positively correlated with the bead width, and when controlling the height of the workpiece, changes in the beam power can result in inconsistent bead width. In other words, in additive manufacturing, both the bead height and bead width depend on the beam power, so the optimal beam power for achieving the target bead height may differ from the optimal beam power for achieving the target bead width. In such cases, the additive manufacturing device described in Patent Document 1 is unable to satisfy the beam power conditions, making it difficult to keep the bead height and bead width within a certain range from the target value. In other words, the additive manufacturing device described in Patent Document 1 has the problem of being unable to simultaneously control the bead width and bead height formed during additive manufacturing.

[0006] The present disclosure has been made in consideration of the above, and aims to provide an additive manufacturing device that can simultaneously control the width and height of a bead formed during additive manufacturing.

[0007] In order to solve the above-mentioned problems and achieve the objectives, the additive manufacturing apparatus of the present disclosure comprises a beam heat source supply unit that outputs a beam that melts the manufacturing material, a current supply unit that passes current through the manufacturing material, a manufacturing material supply unit that supplies the manufacturing material to the workpiece, and a bead shape control unit that acquires bead state information, which is information indicating the state of the base bead of manufacturing material that has been melted and solidified on the workpiece by Joule heat caused by beam irradiation and current flow, and controls at least one of the beam output value, the current value when current is flowing, and the manufacturing material supply speed according to the bead state information so that a new bead formed on the base bead has a predetermined height and width.

[0008] The additive manufacturing device according to the present disclosure has the advantage of being able to simultaneously control the width and height of the bead formed during additive manufacturing.

[0009] FIG. 1 is a diagram showing a schematic example of the configuration of an additive manufacturing apparatus according to embodiment 1. FIG. 2 is a diagram showing an example of the configuration of a rotation mechanism used in the additive manufacturing apparatus according to embodiment 1. FIG. 3 is a diagram showing an example of the functional configuration of a numerical control (NC) device that controls the additive manufacturing apparatus according to embodiment 1. FIG. 4 is a diagram showing a schematic example of how an object is formed by the additive manufacturing apparatus according to embodiment 1.FIG. 1 is a diagram showing the difference in "L" in two cases where the laser output value and current value are made different from each other. FIG. 2 is a diagram explaining the relationship between the state of processing by the additive manufacturing apparatus according to embodiment 1 and the position of the tip of the wire. FIG. 3 is a diagram explaining a method of controlling the processing reference point in the additive manufacturing apparatus according to embodiment 1. FIG. 4 is a flowchart showing an example of the operation procedure in manufacturing a shaped object by the additive manufacturing apparatus according to embodiment 1. FIG. 5 is a diagram showing an example of a laminated object in which the height of a bead is controlled by the additive manufacturing apparatus according to embodiment 1. FIG. 6 is a diagram showing an example of the functional configuration of an NC device that controls the additive manufacturing apparatus according to embodiment 2. FIG. 7 is a diagram explaining how the additive manufacturing apparatus according to embodiment 2 controls the position of the tip of the wire. FIG. 8 is a diagram explaining how the additive manufacturing apparatus according to embodiment 2 controls the position of the tip of the wire. 16A and 16B are diagrams illustrating an example of changes over time in the command values ​​of the process parameters at the start of processing by the additive manufacturing device according to embodiment 4; FIG. 17A is a diagram illustrating an example of changes over time in the command values ​​of the process parameters at the start of processing by the additive manufacturing device according to embodiment 4; FIG. 18A is a diagram illustrating an example of how a molded object is formed when the process parameters are changed according to the time changes shown in FIG. 15 at the start of processing by the additive manufacturing device according to embodiment 4; FIG. 19A is a diagram illustrating an example of how a bead is molded by the additive manufacturing device according to embodiment 5; FIG. 19B is a diagram illustrating an example of how a bead is molded by the additive manufacturing device according to embodiment 5;

[0010] Hereinafter, an additive manufacturing apparatus and an additive manufacturing method according to an embodiment of the present disclosure will be described in detail with reference to the drawings.

[0011] 1 is a diagram schematically illustrating an example of the configuration of an additive manufacturing apparatus according to a first embodiment. The additive manufacturing apparatus 1 is an apparatus that employs a DED additive manufacturing technique. The additive manufacturing apparatus 1 melts a wire W, which is a manufacturing material, with a laser beam LB, and performs additive manufacturing by adding the molten wire W to a workpiece, which is a substrate 91 or a substrate 91 to which the molten wire W has been added.

[0012] In Figure 1, the X-axis, Y-axis, and Z-axis are three axes that are perpendicular to each other. The X-axis and Y-axis are two horizontal axes that are perpendicular to each other. The Z-axis is a vertical axis. For each of the X-axis, Y-axis, and Z-axis, the direction indicated by the arrow is the + direction, and the direction opposite to the arrow is the - direction. The Z-axis direction is the stacking direction in which the beads 93 are stacked.

[0013] The additive manufacturing device 1 includes a laser oscillator 11, a laser output controller 12, a fiber cable 13, a processing head 14, a gas flow regulator 15, a manufacturing material supply unit 16, a rotating member 17, a rotating mechanism 18, a power supply 19, a conductor 20, a power supply output controller 21, a drive controller 22, and an NC device 23.

[0014] The laser oscillator 11 outputs a laser beam LB, which is a beam that melts the wire W. The laser oscillator 11 corresponds to a beam heat source supply unit. The beam is not limited to the laser beam LB, and may be an arc or an electron beam. The laser output controller 12 controls the laser oscillator 11 to control the beam output of the laser oscillator 11. In the following description, the beam output is also referred to as laser output. The fiber cable 13 propagates the laser beam LB output by the laser oscillator 11 to the processing head 14.

[0015] The processing head 14 emits a laser beam LB toward the workpiece. Although not shown, the processing head 14 includes a collimating optical system that collimates the laser beam LB and a focusing lens that focuses the laser beam LB. The processing head 14 can move in the X-axis, Y-axis, and Z-axis directions. The direction of the center line irradiated from the processing head 14 to the workpiece is the Z-axis direction. When the beam is a laser beam LB, the center line is preferably the optical axis. When the beam is other than a laser beam LB, the center line is preferably the point of strongest irradiance in the beam irradiance distribution. The position of the center line may deviate from the optical axis, the point of strongest irradiance, etc., as exemplified above, to the extent that it does not affect the control of additive manufacturing parameters based on the position of the center line. In one example, the center line of the beam may be an axis that passes through the interior of the beam or near the outer periphery of the beam within a predetermined range from the outer periphery of the beam, and is substantially parallel to the direction of travel of the beam.

[0016] The processing head 14 is equipped with a gas nozzle that supplies shielding gas G. By spraying the shielding gas G toward the workpiece, the additive manufacturing device 1 suppresses oxidation of the workpiece and cools the formed bead 93. The bead 93 is formed by melting and solidifying the wire W. The molten bead 94 is the melted portion of the bead 93. The gas flow regulator 15 controls the flow rate of the shielding gas G. Types of shielding gas G include inert gases such as argon, nitrogen, and carbon dioxide.

[0017] The modeling material supply unit 16 supplies wire W, which is a modeling material, to a workpiece, which is a substrate 91 or a substrate 91 to which molten wire W has been added. The modeling material supply unit 16 has a wire spool 161, a rotary motor 162, and a wire nozzle 163. The wire spool 161 is a supply source of wire W. The wire W is wound around the wire spool 161. The wire W is an example of a filler material. The rotary motor 162 rotates the wire spool 161 to supply wire W from the wire spool 161 to the workpiece, and rotates it in the opposite direction to pull wire W back from the workpiece. The wire nozzle 163 is attached and fixed to the processing head 14. The wire nozzle 163 guides the wire W from the wire spool 161 so that it is supplied toward the area on the workpiece to be irradiated with the laser beam LB. In this example, the direction in which the wire W is supplied is oblique to the direction in which the laser beam LB is emitted from the processing head 14 .

[0018] The rotating member 17 supports a substrate 91 on which a three-dimensional object is to be formed. The rotating member 17 functions as a stage that supports the substrate 91. The rotating member 17 may fix the substrate 91. The substrate 91 is placed on the rotating member 17, and the bead 93 is placed on the substrate 91. In one example, the substrate 91 is a plate material, but may be something other than a plate material. The substrate 91 and the substrate 91 on which the bead 93 is formed are also referred to as workpieces.

[0019] The rotation mechanism 18 rotates the rotation member 17. FIG. 2 is a diagram illustrating an example of the configuration of the rotation mechanism used in the additive manufacturing apparatus according to the first embodiment. The substrate 91 is attached to the rotation member 17. The rotation mechanism 18 rotates the rotation member 17, i.e., the substrate 91 attached to the rotation member 17, around the a-axis or c-axis based on a drive command determined by a stage driver 223 (described later). Here, the a-axis is perpendicular to the c-axis. When the rotation member 17 rotates, the relative angle and position between the substrate 91 and the processing head 14 change. FIG. 2 illustrates an example in which the rotation mechanism 18 can rotate around two rotation axes: a c-axis that passes through the center of the substrate mounting surface, which is the upper surface of the rotation member 17 installed on the rotation mechanism 18, and is perpendicular to the substrate mounting surface; and an a-axis that passes through the intersection of the substrate mounting surface and the c-axis and is located within the substrate mounting surface. Furthermore, the rotation mechanism 18 may rotate the rotation member 17 based on a drive command. In one example, the rotation mechanism 18 may be configured to independently rotate the two rotating members 17 in a rotation direction rc about the c-axis and a rotation direction ra about the a-axis. The orientations of the a-axis and c-axis may be arbitrary. In one example, the a-axis may be parallel to the X-axis, and the c-axis may be parallel to the Z-axis. In another example, the rotation mechanism 18 may include a servo motor that rotates in two directions, ra and rc. By using the rotation mechanism 18, for example, it becomes possible to additively manufacture complex shapes that require a five-axis configuration for access to the processing position. Alternatively, the rotation mechanism 18 may not be required. This is because additive manufacturing using the rotation mechanism 18 is not necessary for an additive manufacturing device 1 intended only for manufacturing simple objects such as walls or lines.

[0020] Returning to FIG. 1 , the power supply 19 passes a current through the wire W. Two conductors 20 are connected to the positive and negative poles of the power supply 19. The two conductors 20 connected to the positive and negative poles are connected to the substrate 91 and the wire nozzle 163, respectively. Current from the power supply 19 flows from the positive pole to the conductors 20, the substrate 91, the workpiece, and then to the wire W. The wire W through which the current flows is heated by Joule heat. Note that as long as a current flows through the wire W, the conductors 20 may be connected such that the conductor 20 connected to the positive pole is connected to the wire nozzle 163 and the conductor 20 connected to the negative pole is connected to the substrate 91. The power supply 19 and the conductors 20 correspond to a current supply unit that passes a current through the wire W to melt the wire W, which is a modeling material. The power supply output controller 21 controls the voltage and current of the power supply 19 by controlling the power supply 19. The following describes an example in which the power supply output controller 21 controls the current of the power supply 19.

[0021] In additive manufacturing, both the height and width of the bead 93 depend on the laser output. For this reason, the optimal laser output for obtaining the target height of the bead 93 may differ from the optimal laser output for obtaining the target width of the bead 93. In such cases, it is difficult to keep the height and width of the bead 93 within a certain range from the target value based solely on the laser output condition. Therefore, in the first embodiment, heating of the wire W by Joule heat is adopted so that the height and width of the bead 93 can be controlled independently.

[0022] The drive controller 22 has a head drive unit 221 that drives the processing head 14 , a wire supply drive unit 222 that drives the modeling material supply unit 16 , and a stage drive unit 223 that drives the rotation mechanism 18 .

[0023] The NC device 23 controls the entire additive manufacturing apparatus 1 in accordance with a processing program. The NC device 23 controls the laser oscillator 11 by outputting a laser output command to the laser output controller 12. The NC device 23 controls the processing head 14 by outputting an axis command to the head driver 221. The NC device 23 controls the modeling material supply unit 16 by sending a supply command to the wire supply driver 222. The NC device 23 controls the rotation mechanism 18 by sending a rotation command to the stage driver 223. The NC device 23 controls the flow rate of the shielding gas G by outputting a gas supply command to the gas flow regulator 15. The NC device 23 controls the current or voltage flowing from the power supply 19 by outputting a power output command to the power output controller 21. The power output command is a current command or a voltage command.

[0024] 3 is a diagram showing an example of the functional configuration of an NC device that controls the additive manufacturing device according to embodiment 1. A machining program 31, which is an NC program, is input to the NC device 23. The machining program 31 is created by a CAM (Computer Aided Manufacturing) device.

[0025] The NC device 23 has a program analysis unit 32 that analyzes the machining program 31, a machining condition table storage unit 33 that stores a machining condition table, a machining condition setting unit 34 that sets the machining conditions, an axis command generation unit 35 that generates axis commands, a laser command generation unit 36 ​​that generates laser output commands, a supply command generation unit 37 that generates supply commands, and a power command generation unit 38 that issues power output commands.

[0026] The program analysis unit 32 analyzes the movement path for moving the machining head 14 based on the description of the machining program 31. The program analysis unit 32 outputs the analysis result of the movement path to the axis command generation unit 35. In addition, the program analysis unit 32 outputs information for setting machining conditions to the machining condition setting unit 34.

[0027] The machining condition table storage unit 33 stores a machining condition table in which data of various machining conditions is stored. The machining condition setting unit 34 sets the machining conditions by reading the data of the machining conditions from the machining condition table in accordance with the information for setting the machining conditions. The NC device 23 may obtain the data of the specified machining conditions from the data of various machining conditions pre-stored in the machining condition table, or may obtain the data of the machining conditions from the machining program 31 in which the data of the machining conditions is described.

[0028] The axis command generation unit 35 generates axis commands, which are a group of interpolated points on the movement path for each unit time, based on the analysis results of the movement path. In the following description, the interpolated points are also referred to as command points. The head driver 221 drives the machining head 14 based on the axis commands generated by the axis command generation unit 35. In one example, the axis command includes the position of the intersection between the center line of the laser beam LB and the traveling direction of the wire W.

[0029] The laser command generating unit 36 ​​generates a laser output command based on the machining conditions set by the machining condition setting unit 34. The supply command generating unit 37 generates a supply command based on the machining conditions set by the machining condition setting unit 34. The power command generating unit 38 generates a power output command based on the machining conditions set by the machining condition setting unit 34. Here, the power output command is a current command.

[0030] The NC device 23 includes a bead shape controller 39, a feedforward controller 40, and an adder 41. The additive manufacturing apparatus 1 includes a bead condition detection unit 24 that detects the state of the bead 93. The bead condition detection unit 24 includes various sensors, such as a camera, a thermometer, and a shape measuring device, that acquire bead condition information indicating the state of the bead 93. In this example, the bead condition detection unit 24 acquires bead condition information about an already formed bead 93 that serves as the base for the bead 93 to be formed. The state of the bead 93 includes the shape of the bead 93. The detection results from the bead condition detection unit 24 are input to the bead shape controller 39. The bead shape controller 39 is a control unit that performs control to improve the shape accuracy of the bead 93, and controls process parameters such as a laser output command value, a feed rate command value, and a current command value based on the detection results from the bead condition detection unit 24, i.e., the bead condition information.

[0031] The bead shape controller 39 controls the height and width of the bead 93 to be formed by controlling the process parameters. The height of the bead 93 is the length of the bead 93 in the stacking direction. The width of the bead 93 is the length of the bead 93 in a direction perpendicular to the direction in which the processing head 14 is moved and the stacking direction. Specifically, the bead shape controller 39 acquires bead state information, which is information indicating the state of the base bead 93 formed by melting and solidifying the wire W on the workpiece by Joule heat caused by irradiation with the laser beam LB and current application, and controls at least one of the laser output value, current value, and wire W feed speed according to the bead state information so that the new bead 93 formed on the base bead 93 has a predetermined height and width. In one example, the bead shape controller 39 acquires the height of the upper surface of the base bead 93 as bead condition information, and controls the laser output command value, the feed rate command value, and the current command value so that the height of the bead 93 to be formed on the base bead 93 from the upper surface of the base 91 is constant, regardless of the height of the upper surface of the base bead 93. The bead shape controller 39 corresponds to a bead shape control unit. For example, if the direction in which the processing head 14 is moved is the X-axis direction, the bead shape controller 39 controls the height of the bead 93 in the Z-axis direction and the width of the bead 93 in the Y-axis direction. The bead condition information is the detection result by the bead condition detection unit 24. Note that the bead shape controller 39 only needs to control at least one of the laser output command value and the current command value.

[0032] The bead shape controller 39 outputs the controlled laser output command to the laser output controller 12 and the feedforward controller 40. The laser output controller 12 controls the laser oscillator 11 so that the laser output command value is the laser output command value indicated by the controlled laser output command.

[0033] The bead shape controller 39 outputs the controlled supply command to the wire supply driver 222 and the feedforward controller 40. The wire supply driver 222 controls the modeling material supply unit 16 so that the supply speed of the wire W becomes the command value indicated by the controlled supply command.

[0034] The bead shape controller 39 outputs the controlled current command to the power supply output controller 21 and the feedforward controller 40. The power supply output controller 21 controls the power supply 19 so that the current command value indicated by the controlled current command is achieved.

[0035] The feedforward controller 40 includes a position calculation unit 401 that calculates the tip of the wire W, and a correction amount calculation unit 402 that calculates a correction amount for controlling the position of the machining head 14 .

[0036] The position calculation unit 401 calculates the tip position, which is the position of the part of the wire W whose temperature has reached the melting point of the wire W due to Joule heat caused by irradiation of the laser beam LB and current flow, based on the feed speed of the wire W being supplied to the workpiece, the output value of the laser beam LB, and the current value when current is flowing.

[0037] Specifically, the position calculation unit 401 calculates the tip position of the wire W before machining is performed based on the feed speed of the wire W, the laser output value of the laser oscillator 11, and the current value of the power supply output controller 21. In the example of Fig. 3, the position calculation unit 401 calculates the tip position of the wire W based on the laser output command, the feed command, and the current command after control in the bead shape controller 39. The position calculation unit 401 outputs the calculation result of the tip position to the correction amount calculation unit 402. Calculating the tip position of the wire W by the position calculation unit 401 enables feedforward control.

[0038] The position calculation unit 401 calculates the tip position of the wire W based on processing conditions including the feed speed of the wire W, the laser output value of the laser oscillator 11, and the current value of the power supply output controller 21. The tip position of the wire W can be calculated from the values ​​of each processing condition stored in advance in the processing condition table of the additive manufacturing device 1. Therefore, compared to a method of observing the tip position of the wire W using a camera or the like and estimating the tip position, it is possible to calculate the tip position of the wire W in more real time.

[0039] The correction amount calculation unit 402 controls the position of the processing reference point, which is the intersection of the center line of the laser beam LB heading toward the workpiece and the traveling direction of the wire W supplied from the modeling material supply unit 16 toward the workpiece, at least in the stacking direction in which the bead 93 is stacked on the workpiece. The correction amount calculation unit 402 controls the position of the processing reference point based on the tip position calculated by the position calculation unit 401.

[0040] Specifically, the correction amount calculation unit 402 receives as input the measured value of the displacement amount from the top surface of the workpiece to the command point measured by the displacement amount measurement unit 25 of the additive manufacturing apparatus 1. The displacement amount measurement unit 25 is a sensor such as a laser displacement meter. The correction amount calculation unit 402 calculates the correction amount in the stacking direction based on the calculation result of the tip position and the measured displacement amount. The correction amount calculation unit 402 outputs the calculation result of the correction amount to the adder 41.

[0041] The adder 41 adds a correction amount to the axis command generated by the axis command generation unit 35. The correction amount calculation unit 402 and the adder 41 function as a correction unit that controls the position of the machining reference point at least in the Z-axis direction, which is the stacking direction, based on the tip position calculated by the position calculation unit 401. The adder 41 outputs the addition result, i.e., the controlled axis command, to the head drive unit 221.

[0042] 4 is a diagram schematically illustrating how a model is formed by the additive manufacturing apparatus according to embodiment 1. In FIG. 4, "θ" represents the angle between the direction of travel of the wire W from the wire nozzle 163 toward the workpiece and the X-axis, i.e., the horizontal direction. Here, it is assumed that the processing head 14 is traveling in the X-axis direction.

[0043] The intersection of the center line C of the laser beam LB directed toward the workpiece and the traveling direction of the wire W directed from the wire nozzle 163 toward the workpiece is set as a processing reference point RP, which is the reference point of the processing head 14. The additive manufacturing device 1 drives the processing head 14 so that the processing reference point RP coincides with the position of a command point based on the processing program 31.

[0044] In order to continue stable machining without causing a drop phenomenon in which a lump of the wire W remains on the wire W after melting or a stub phenomenon in which the wire W before melting collides with the workpiece, the additive manufacturing apparatus 1 is required to maintain an appropriate positional relationship between the workpiece and the tip position of the wire W, i.e., the position of the tip portion Wa. The additive manufacturing apparatus 1 can maintain an appropriate positional relationship between the workpiece and the machining reference point RP by estimating the position of the tip portion Wa of the wire W and controlling the position of the machining reference point RP based on the estimation result. The additive manufacturing apparatus 1 estimates the position of the tip portion Wa by calculating the position of the tip portion Wa in the position calculation unit 401.

[0045] In FIG. 4 , "L" represents the distance in the X-axis direction from the point at which the wire W fed from the wire nozzle 163 enters the laser beam LB to the position of the tip Wa where the temperature reaches the melting point. In FIG. 4 , "L" represents the distance in the X-axis direction, but if the processing head 14 is moving in a direction other than the X-axis direction, it represents the distance in the direction of travel of the processing head 14. Alternatively, "L" represents the position of the tip Wa in the direction of travel of the processing head 14 when the position at which the wire W projected in the direction of travel of the processing head 14 is incident on the laser beam LB is set to 0. Hereinafter, the incident position of the wire W on the laser beam LB is referred to as the incident point IP. Furthermore, the direction of travel of the processing head 14 is referred to as the processing direction.

[0046] FIG. 5 is a diagram showing the difference in "L" between two cases where the feed speed, laser output value, and current value are different from each other. In the case (a) of FIG. 5, "L" is longer than in the case (b). In other words, in the case (a), the feed speed is higher, the laser output value is lower, or the current value is lower compared to the case (b). The position calculation unit 401 calculates the position of the tip Wa of the wire W based on the relationship between the position of the tip Wa and the process parameters. Calculating the position of the tip Wa means calculating "L," which is the position of the tip Wa relative to the incident point IP in the machining direction.

[0047] The position "L" of the tip Wa varies depending on the process parameters of the feed speed, laser output value, and current value, and is therefore expressed by the following equation (1).

[0048] L=f(F,P,I)...(1)

[0049] Here, "F" is the command value for the wire W feed speed. "P" is the command value for the laser output. "I" is the command value for the current. "f" indicates that it is a function for finding "L", and the values ​​in parentheses "( )" indicate the variables of the function "f". The function "f" has the property that "L" becomes larger when the feed speed "F" becomes larger, "L" becomes smaller when the laser output "P" becomes larger, and "L" becomes smaller when the current value "I" becomes larger. The function "f" can be simplified and expressed by the following equation (2).

[0050] L=(K1・F) / (K2・P+K3・I) ...(2)

[0051] The constant "Ki (i = 1, 2, 3)" used in equation (2) is a constant that changes depending on the physical properties of the wire W, the direction of travel "θ" of the wire W, and the surrounding environment of the additive manufacturing apparatus 1. The equation for the function "f" that finds "L", which is the position of the tip Wa of the wire W, does not have to be in the form of equation (2), as long as the correspondence between an increase or decrease in the variables "F", "P", and "I" and an increase or decrease in "L" has the same properties as equation (2). The constant "Ki" can be determined by any method, such as by using the preliminary experiment described in embodiment 3.

[0052] Next, the relationship between the machining status by the additive manufacturing apparatus 1 and the position of the tip portion Wa of the wire W will be described. FIG. 6 is a diagram illustrating the relationship between the machining status by the additive manufacturing apparatus according to embodiment 1 and the position of the tip portion of the wire. FIG. 6 schematically shows the machining status in four cases (a) to (d) in which the supply speed, laser output value, or current value are different from one another. In the four cases (a) to (d), the position of the tip portion Wa in the Z-axis direction is different from one another. In case (a), the position of the tip portion Wa is located furthest vertically upward among the four cases. In FIG. 6, the position of the tip portion Wa descends in the −Z-axis direction in the order of (a), (b), (c), and (d).

[0053] In the case of (a), the position of the tip portion Wa is away from the molten bead 94 in the +Z-axis direction. In such a case, the wire W melts at a position away from the molten bead 94, and a drop 81 is formed at the tip portion Wa of the wire W. In other words, a drop phenomenon occurs.

[0054] In the case of (b), the position of the tip portion Wa is located in the +Z-axis direction from the molten bead 94. In addition, a link 82 is formed between the position of the tip portion Wa and the molten bead 94 due to the surface tension of the molten material of the wire W. In such a case, since the position of the tip portion Wa and the molten bead 94 are connected via the link 82, it is possible to continue processing. However, since the link 82 is easily broken by the influence of external disturbances, etc., the state of the case of (b) is likely to shift to the state of the case of (a), and the drop phenomenon is likely to occur.

[0055] In case (c), the position of the tip Wa is in the -Z axis direction from the top surface of the molten bead 94 and vertically above the bottom surface of the molten pool 96. In such a case, contact between the molten wire W and the molten bead 94 is maintained, so the drop phenomenon does not occur. Furthermore, the distance between the bottom surface of the molten pool 96 and the position of the tip Wa is maintained, so the stub phenomenon does not occur. In case (c), the additive manufacturing device 1 does not experience either the drop phenomenon or the stub phenomenon, and can continue stable processing.

[0056] In the case of (d), the position of the tip Wa is located in the −Z-axis direction further than the bottom surface of the molten bead 94. Alternatively, when the wire W reaches the bottom surface of the molten pool 96, the wire W is supplied so that the position of the tip Wa moves further in the −Z-axis direction, whereby the tip Wa of the wire W is pressed against the bottom surface of the molten pool 96. In the case of (d), a stub phenomenon occurs.

[0057] 6(c), the additive manufacturing apparatus 1 can continue stable processing in a state where the tip portion Wa is located between the top surface of the molten bead 94 and the bottom surface of the molten pool 96. The additive manufacturing apparatus 1 has difficulty processing when the tip portion Wa is located in the +Z axis direction relative to the top surface of the molten bead 94 or in the −Z axis direction relative to the bottom surface of the molten pool 96.

[0058] Next, control of the position of the processing reference point RP by the additive manufacturing apparatus 1 will be described. Fig. 7 is a diagram illustrating a method for controlling the processing reference point in the additive manufacturing apparatus according to embodiment 1. Fig. 7(a) schematically shows the position of the tip Wa of the wire W and the state of the workpiece before controlling the position of the processing reference point RP. Fig. 7(b) schematically shows the position of the tip Wa of the wire W and the state of the workpiece after controlling the position of the processing reference point RP. By controlling the position of the processing reference point RP, the position of the tip Wa or the workpiece transitions from the state shown in Fig. 7(a) to the state shown in Fig. 7(b).

[0059] 7A, the position of the tip end Wa is spaced vertically upward from the molten bead 94. The position calculation unit 401 receives as input a laser output command value indicated by the laser output command after control by the bead shape controller 39, a supply speed command value indicated by the supply command after control by the bead shape controller 39, and a current command value indicated by the current command after control by the bead shape controller 39. The position calculation unit 401 calculates the distance "L" in the machining progress direction from the incident point IP to the tip end Wa based on the above-mentioned equation (1). The position calculation unit 401 outputs the calculation result of the distance "L" to the correction amount calculation unit 402.

[0060] 7A, the displacement amount "h" in the Z-axis direction from the upper surface of the workpiece, that is, from the upper surface of the substrate 91 to the processing reference point RP, is measured by a displacement amount measuring unit 25 such as a laser displacement meter. The measured value of the displacement amount "h" is input to the correction amount calculating unit 402.

[0061] The vertical distance from when the wire W is incident on the laser beam LB to the processing reference point RP is expressed as (R / 2) tan θ, where "R" is the diameter of the laser beam LB and "θ" is the direction of travel of the wire W.

[0062] The correction amount calculation unit 402 calculates the distance between the upper surface of the substrate 91 and the position of the tip end Wa in the Z-axis direction as the correction amount. The correction amount "ΔZ" is expressed by the following equation (3).

[0063] ΔZ=-h-(R / 2)tanθ+L・tanθ...(3)

[0064] The correction amount calculation unit 402 calculates the correction amount "ΔZ" based on equation (3). The correction amount calculation unit 402 outputs the calculation result of "ΔZ" to the adder 41. The adder 41 adds the correction amount "ΔZ" to the axis command generated by the axis command generation unit 35. By controlling the machining head 14 in accordance with the axis command after control, the position of the machining reference point RP moves by "ΔZ" in the -Z axis direction from the position in the state shown in FIG. 7A. By moving the position of the machining reference point RP, the position of the tip portion Wa comes into contact with the molten bead 94, as shown in FIG. 7B. That is, in this example, the correction amount calculation unit 402 controls the position in the Z axis direction so that the position of the tip portion Wa comes into contact with the upper surface of the substrate 91 or the molten bead 94.

[0065] In this way, the additive manufacturing apparatus 1 controls the position of the processing reference point RP in the stacking direction based on the calculation result of the position of the tip end Wa of the wire W. Even if the process parameters change during processing, the additive manufacturing apparatus 1 can bring the position of the tip end Wa into contact with the molten bead 94 by controlling the position of the processing reference point RP. Furthermore, correcting the position of the tip end Wa of the wire W during processing can suppress the occurrence of the stub phenomenon and the drop phenomenon. In other words, the additive manufacturing apparatus 1 can maintain a state in which stable processing is possible by constantly bringing the position of the tip end Wa into contact with the molten bead 94.

[0066] Next, a description will be given of the procedure of an additive manufacturing method in which the additive manufacturing apparatus 1 according to Embodiment 1 manufactures a shaped object. Fig. 8 is a flowchart showing an example of the operation procedure in manufacturing a shaped object by the additive manufacturing apparatus 1 according to Embodiment 1.

[0067] First, the additive manufacturing apparatus 1 energizes the wire W, which is a modeling material (step S1). The additive manufacturing apparatus 1 energizes the wire W by causing a current to flow from the power supply 19 in accordance with a current command. The process of step S1 corresponds to a current application process.

[0068] Next, the additive manufacturing apparatus 1 supplies the wire W, which is a modeling material, to the workpiece (step S2). The modeling material supply unit 16 supplies the wire W at a supply speed of the wire W in accordance with the supply command. The process of step S2 corresponds to a modeling material supply process.

[0069] Thereafter, the additive manufacturing apparatus 1 irradiates the workpiece with the laser beam LB by outputting the laser beam LB from the laser oscillator 11 (step S3). The laser oscillator 11 outputs the laser beam LB at a laser output command value according to the laser output command. The process of step S3 corresponds to a beam irradiation process of irradiating the workpiece with a beam that melts the modeling material. In this manner, the additive manufacturing apparatus 1 melts the supplied wire W with the laser beam LB to form a bead 93.

[0070] Next, the state of the bead 93 is detected by the bead state detection unit 24 (step S4). Step S4 corresponds to a bead state detection step of detecting the state of the base bead 93, which is formed by melting and solidifying the wire W on the workpiece due to Joule heat generated by irradiation and energization of the laser beam LB. The additive manufacturing device 1 then controls at least one of the current command value, laser output command value, and feed speed command value based on the detection result so that the bead 93 has a desired height and width (step S5). Step S5 corresponds to a command value control step of controlling at least one of the output value of the laser beam LB, the current value during energization, and the feed speed of the wire W, according to the bead state, so that a new bead 93 formed on the base bead 93 has a predetermined height and width.

[0071] Next, the additive manufacturing apparatus 1 calculates the position of the tip Wa of the wire W based on the current command value, laser output command value, and supply speed command value after control in step S5 (step S6). Step S6 is a position calculation step in which the tip position, which is the position of the part of the modeling material whose temperature has reached the melting point of the modeling material due to Joule heat caused by beam irradiation and current flow, is calculated based on the supply speed of the modeling material supplied to the workpiece, the beam output value, and the current value during current flow. In step S6, the additive manufacturing apparatus 1 estimates the position of the tip Wa during processing.

[0072] The additive manufacturing apparatus 1 then controls the position of the processing reference point RP based on the calculation result of the position of the tip portion Wa in step S6 (step S7). Step S7 is a position control step in which the position of the processing reference point RP, which is the intersection of the center line C of the laser beam LB output from the laser oscillator 11 and the traveling direction of the wire W supplied from the wire nozzle 163, is controlled at least in the stacking direction, which is the direction in which the bead 93 formed by melting and solidifying the wire W is stacked. In this position control step, the correction amount calculation unit 402 and the adder 41 control the position of the processing reference point RP based on the tip position calculated by the position calculation unit 401. The additive manufacturing apparatus 1 controls at least one of the current value, laser output value, and feed speed to achieve the desired height and width of the bead 93, and repeats the operation of forming the bead 93 while controlling the position of the processing reference point RP. The additive manufacturing apparatus 1 manufactures a three-dimensional object by stacking the beads 93 on the substrate 91.

[0073] Next, a description will be given of the effect achieved when the additive manufacturing device 1 according to embodiment 1 controls the height of the bead 93. Fig. 9 is a diagram schematically illustrating an example of a laminate in which the height of the bead is controlled by the additive manufacturing device according to embodiment 1.

[0074] 9A is a horizontal view of a shaped object in which a bead 93b is stacked vertically above a bead 93a. The bead 93b is stacked on top of the bead 93a. The bead 93a has a recess 931 on its upper surface. When processing the bead 93b, the shape of the bead 93a is measured, and the bead shape controller 39 controls the height of the bead 93b from the upper surface of the substrate 91 to be constant based on the measurement results, and issues output commands for the feed speed of the wire W, the laser output value of the laser beam LB, and the current value of the power supply 19. The bead 93, which is the workpiece, is measured using a sensor such as a laser displacement meter.

[0075] Since the height of the bead 93 is positively correlated with the magnitude of the wire W feed speed, when it is desired to increase the height of the bead 93, the bead shape controller 39 outputs a feed command to increase the feed speed. However, if the wire W feed speed is high, a stub phenomenon occurs. Therefore, the bead shape controller 39 outputs a laser output command or a current command to increase the laser output or the current value of the power supply 19, thereby inputting heat to the wire W. This makes it possible to increase the wire W feed speed while suppressing the occurrence of the stab phenomenon. On the other hand, when it is desired to decrease the height of the bead 93, the bead shape controller 39 outputs a feed command to decrease the feed speed. However, if the wire W feed speed is low, a drop phenomenon occurs. Therefore, the bead shape controller 39 outputs a laser output command or a current command to decrease the laser output or the current value of the power supply 19, thereby inputting heat to the wire W. This makes it possible to reduce the wire W feed speed while suppressing the occurrence of the drop phenomenon.

[0076] FIG. 9B is a vertical view of a bead 93b formed when the laser output and the feed rate are changed to control the height of the bead 93b. In other words, the current value is not changed. The width of the bead 93 is positively correlated with the laser output. The bead shape controller 39 controls the laser output to prevent stub and drop phenomena when controlling the height of the bead 93b, which results in the bead 93 having an indentation 931 on its upper surface. In FIG. 9A, the bead 93b is formed on a bead 93a having an indentation 931 on its upper surface. The indentation 931 gradually deepens, and after reaching the bottom of the indentation 931, the depth gradually becomes shallower. Therefore, when forming the bead 93b on the indentation 931, the feed rate is adjusted to gradually increase and decrease the height of the bead 93b. Furthermore, as described above, when the supply speed is increased, a command to increase the laser output is output, and when the supply speed is decreased, a command to decrease the laser output is output. Since the width of the bead 93 is positively correlated with the magnitude of the laser output, as shown in (b), the width W2 of the bead 93b in the portion corresponding to the recess 931 becomes thicker than the width W1 of the other portion.

[0077] FIG. 9C shows a vertical view of a bead 93b formed when the current value of the power supply 19 is changed along with the feed rate to control the height of the bead 93. In other words, the laser output is not changed. The width of the bead 93 has little correlation with the current value. By changing the current value without changing the laser output to control the height of the bead 93b, the width of the bead 93 can be maintained constant. That is, whether the current value is reduced in the portion of the bead 93a other than the recess 931 or increased in the recess 931, the width W1 of the bead 93b can be maintained at a substantially constant value along the extension direction. Furthermore, since the feed rate is controlled by location as shown in FIG. 9A while maintaining the width W1 of the bead 93 constant, the height of the bead 93 can be maintained at any desired size. In this way, by controlling the current value of the power supply 19 with the bead shape controller 39, the position of the tip Wa of the wire W can be controlled as desired.

[0078] As described above, in the additive manufacturing apparatus 1 that melts the wire W using Joule heat of an electric current in addition to the laser beam LB, the width of the bead 93 can be maintained uniform by controlling not only the laser output value but also the electric current value when controlling the height of the bead 93. Furthermore, by using not only the laser beam LB but also the electric current as a heat source, it is possible to increase the heat input to the wire W. As a result, the maximum laser output used for processing the laser beam LB can be reduced, allowing for the use of a more inexpensive laser oscillator 11. Furthermore, when the position of the top surface of the base bead 93a is not constant and has irregularities, controlling the electric current value rather than the laser output value to melt the wire W when controlling the height of the bead 93, i.e., controlling the electric current value without changing the laser output value, allows for the tip position of the wire W to be adjusted arbitrarily without sacrificing the width and height of the bead 93.

[0079] According to the first embodiment, the additive manufacturing apparatus 1 melts the shaping material supplied to the workpiece by irradiating it with a beam and generating Joule heat from the current. By adding heat input from the Joule heat of the current to the shaping material heating, the height of the workpiece can be controlled by controlling the current value rather than the laser output, thereby maintaining a constant width for the bead 93. Furthermore, the additive manufacturing apparatus 1 can estimate the position of the tip Wa of the shaping material supplied to the workpiece by irradiating it with a beam and generating Joule heat from the current during the shaping process. Furthermore, by controlling the position of the processing reference point RP in the stacking direction based on the calculated position of the tip Wa, the additive manufacturing apparatus 1 can position the tip Wa of the wire W between the bottom surface of the molten pool 96 and the top surface of the molten bead 94, thereby maintaining stable processing. Furthermore, the position of the tip of the shaping material during processing can be calculated from the laser output command value, current command value, and wire W supply speed command value, allowing the tip position to be calculated in real time within a short period of time. Here, "real time" means that the calculation is performed simultaneously or immediately within a short period of time, and the position of the machining reference point RP and the machining state are controlled based on the calculated tip position, but the time is short enough that this control is not affected. As a result, the additive manufacturing device 1 can perform feedforward control.

[0080] Embodiment 2 In embodiment 2, a method of controlling process parameters based on "L" calculated by the position calculation unit 401 will be described. By controlling the process parameters based on "L" calculated by the position calculation unit 401 during processing, it is possible to maintain the position of the tip Wa of the wire W within the irradiation range of the laser beam LB during processing. In embodiment 2, the same components as in embodiment 1 are given the same reference numerals, and the description will mainly focus on configurations that differ from embodiment 1.

[0081] Fig. 10 is a diagram showing an example of the functional configuration of an NC device that controls the additive manufacturing apparatus according to embodiment 2. The NC device 23 in Fig. 10 has a processing condition adjustment unit 403 added to the functional configuration of the NC device 23 that controls the additive manufacturing apparatus 1 shown in Fig. 3.

[0082] The feedforward controller 40 has a machining condition adjustment unit 403. The machining condition adjustment unit 403 receives as input a calculation result of the position of the tip portion Wa of the wire W, a supply command, a laser output command, and a current command. The machining condition adjustment unit 403 calculates a correction amount for at least one of the supply speed, the laser output value, and the current value based on the tip position calculated by the position calculation unit 401 so that the position of the tip portion Wa of the wire W falls within the irradiation range of the laser beam LB. The machining condition adjustment unit 403 inputs the calculation result of the correction amount to the adder 41. The machining condition adjustment unit 403 only needs to calculate a correction amount for at least one of the supply speed, the laser output value, and the current value. However, for those for which no correction amount has been calculated, the correction amount may be treated as 0.

[0083] An adder 41 is also added downstream of the bead shape controller 39. The adder 41 adds correction amounts to the controlled supply command, controlled laser output command, and controlled current command output by the bead shape controller 39. The adder 41 outputs the added process parameters of the controlled supply speed, laser output value, and current value to the laser output controller 12, the wire supply drive unit 222, and the power supply output controller 21, respectively. The processing condition adjustment unit 403 and the adder 41 correspond to a processing condition adjustment processing unit that controls at least one of the supply speed, beam output value, and current value based on the tip position calculated by the position calculation unit 401 so that the position of the tip end Wa of the modeling material falls within the beam irradiation range.

[0084] 11 and 12 are diagrams illustrating how the additive manufacturing apparatus according to the second embodiment controls the position of the wire tip. In FIGS. 11 and 12 , a tip position maintenance range, which is a range within the irradiation range of the laser beam LB where the position of the tip Wa of the wire W is unlikely to deviate from the irradiation range of the laser beam LB, is set. In the irradiation range of the laser beam LB on a plane including the machining direction and the wire W direction, if the position of the incident point IP in the machining direction (in this example, the X-axis direction) is set to 0, the tip position maintenance range is a range between "TL" and "TH." "TL" and "TH" are values ​​greater than 0 and smaller than the diameter "R" of the laser beam LB. In machining, if the position "L" of the tip Wa in the machining direction relative to the incident point IP is smaller than "TL," the position of the tip Wa of the wire W is likely to deviate from the irradiation range of the laser beam LB. In other words, "TL" is a threshold value at which the position of the tip Wa is likely to deviate from the irradiation range toward the wire nozzle 163. Furthermore, in machining, if the position "L" of the tip Wa in the machining direction relative to the incident point IP is greater than "TH," the position of the tip Wa of the wire W is likely to deviate from the irradiation range of the laser beam LB. In other words, "TH" is the threshold value at which the position of the tip Wa is likely to deviate from the irradiation range to the opposite side of the wire nozzle 163.

[0085] 11A shows a state in which the position "L" of the tip Wa of the wire W during processing is greater than the threshold value "TH". In this case, the processing condition adjustment unit 403 controls the process parameters so that "L" becomes smaller than the threshold value "TH". After the control, as shown in FIG. 11B, the position "L" of the tip Wa becomes smaller than the threshold value "TH".

[0086] Let "L" after control by the processing condition adjustment unit 403 be "L1a", and let "F" before control when only the supply speed value "F" of the process parameter is controlled be "F1", and let "F" after control be "F1a". Then, the correction value of "F" is expressed by the following equation (4) using equation (2).

[0087] F1a-F1=L1a・(K2・P1+K3・I1) / K1−F1...(4)

[0088] Here, "P1" and "I1" indicate the laser output value and current value, respectively. The correction amount of "F" is input from the processing condition adjustment unit 403 to the adder 41 and added to the supply command from the bead shape controller 39. By controlling the supply speed, the position of the tip Wa of the wire W becomes smaller than the threshold value "TH", and the position of the tip Wa falls within the tip position maintenance range, preventing it from moving out of the irradiation range of the laser beam LB.

[0089] Next, a case where only the laser output value "P" of the process parameter is controlled will be described. If "P" after controlling only the laser output value "P" of the process parameter is set to "P1a", the correction value of "P" is expressed by the following equation (5) using equation (2).

[0090] P1a-P1=(K1・F1-K3・I1・L1a) / (L1a・K2)-P1...(5)

[0091] The correction amount of "P" is input from the processing condition adjustment unit 403 to the adder 41 and added to the laser output command from the bead shape controller 39. By controlling the laser output, the position of the tip Wa of the wire W becomes smaller than the threshold value "TH", and the position of the tip Wa falls within the tip position maintenance range, preventing it from moving out of the irradiation range of the laser beam LB.

[0092] Next, a case where only the current value "I" of the process parameter is controlled will be described. When the current value "I" of the process parameter is controlled only, the post-control "I" is represented as "I1a." The correction value of "I" is expressed by the following equation (6) using equation (2).

[0093] I1a-I1=(K1・F1-K2・P1・L1a) / (L1a・K3)-I1...(6)

[0094] The correction amount of "I" is input from the processing condition adjustment unit 403 to the adder 41 and added to the current command from the bead shape controller 39. By controlling the current value, the position of the tip Wa of the wire W becomes smaller than the threshold value "TH", and the position of the tip Wa falls within the tip position maintenance range, preventing it from moving out of the irradiation range of the laser beam LB.

[0095] 12A shows a state in which the position "L" of the tip Wa of the wire W during processing is smaller than the threshold value "TL". In this case, the processing condition adjustment unit 403 controls the process parameters so that "L" is larger than the threshold value "TL". After the control, as shown in FIG. 12B, the position "L" of the tip Wa becomes larger than the threshold value "TL".

[0096] Let "L" after control in the processing condition adjustment unit 403 be "L2a", let "F" before control when only the supply speed value "F" of the process parameter is controlled be "F2", and let "F" after control be "F2a". Then, the correction value of "F" is expressed by the following equation (7) using equation (2).

[0097] F2a-F2=L2a・(K2・P2+K3・I2) / K1-F2...(7)

[0098] Here, "P2" and "I2" indicate the laser output value and current value, respectively. The correction amount of "F" is input from the processing condition adjustment unit 403 to the adder 41 and added to the supply command from the bead shape controller 39. By controlling the supply speed, the position of the tip Wa of the wire W becomes larger than the threshold value "TL", and the position of the tip Wa falls within the tip position maintenance range, preventing it from moving out of the irradiation range of the laser beam LB.

[0099] Next, a case where only the laser output value "P" of the process parameter is controlled will be described. If "P" after controlling only the laser output value "P" of the process parameter is set to "P2a", the correction value of "P" is expressed by the following equation (8) using equation (2).

[0100] P2a-P2=(K1・F2-K3・I2・L2a) / (L2a・K2)-P2...(8)

[0101] The correction amount of "P" is input from the processing condition adjustment unit 403 to the adder 41 and added to the laser output command from the bead shape controller 39. By controlling the laser output, the position of the tip Wa of the wire W becomes larger than the threshold value "TL", and the position of the tip Wa falls within the tip position maintenance range, preventing it from moving out of the irradiation range of the laser beam LB.

[0102] Next, a case where only the current value "I" of the process parameter is controlled will be described. When the current value "I" of the process parameter is controlled only, the post-control "I" is represented as "I2a." The correction value of "I" is expressed by the following equation (9) using equation (2).

[0103] I2a-I2=(K1・F2-K2・P2・L2a) / (L2a・K3)-I2...(9)

[0104] The correction amount of "I" is input from the processing condition adjustment unit 403 to the adder 41 and added to the current command from the bead shape controller 39. By controlling the current value, the position of the tip Wa of the wire W becomes larger than the threshold value "TL", and the position of the tip Wa falls within the tip position maintenance range, preventing it from moving out of the irradiation range of the laser beam LB.

[0105] 11 and 12, the position of the tip Wa of the wire W can be controlled by controlling at least one of the laser output value, the feed speed, and the current value, but two or three of the laser output value, the feed speed, and the current value may be controlled simultaneously. In one example, when controlling the laser output value, if the laser output value after control is greater than the range that can be output by the laser oscillator 11, the feed speed or the current value may be controlled. In this way, the process parameter for which the processing condition adjustment unit 403 outputs a correction amount may be at least one of the laser output value, the feed speed, and the current value.

[0106] According to the second embodiment, the additive manufacturing apparatus 1 can control the process parameters based on the position "L" of the tip portion Wa in the processing progress direction when the incident point IP calculated by the position calculation unit 401 is used as a reference. By controlling the process parameters based on "L" calculated by the position calculation unit 401 during processing, it becomes possible to perform processing while maintaining the position of the tip portion Wa within the irradiation range of the laser beam LB. Furthermore, in order to prevent the tip position of the wire W from falling outside the irradiation range of the laser beam LB due to an increase or decrease in the supply speed of the wire W, it becomes possible to adjust the supply speed and at least one of the laser output value and current value to keep the tip position of the wire W within the irradiation range of the laser beam LB.

[0107] Embodiment 3. In embodiment 1, the constant "Ki" can be determined by any method. In embodiment 3, a method for determining the constant "Ki" by a preliminary experiment will be described. By determining the constant "Ki" based on the results of a preliminary experiment using the additive manufacturing device 1 and the modeling material actually used in processing, the additive manufacturing device 1 becomes able to estimate the position of the tip portion Wa with high accuracy. In embodiment 3, the same components as in embodiments 1 and 2 are assigned the same reference numerals, and the description will mainly focus on configurations that differ from embodiments 1 and 2.

[0108] In the third embodiment, the additive manufacturing apparatus 1 determines the relationship between the boundary value of the supply speed, the laser output value of the laser oscillator 11, and the current value of the power supply 19 through a preliminary experiment. The boundary value of the supply speed is the minimum value of the supply speed when the wire W supplied toward the laser beam LB passes through the laser beam LB without melting. The position calculation unit 401 calculates the constant "Ki" based on the relationship between the boundary value of the supply speed and the laser output and current values. Specifically, the position calculation unit 401 calculates the tip position using a function indicating the relationship between the tip position, the laser output value, the current value, and the supply speed. Furthermore, the position calculation unit 401 calculates the constant "Ki" used in the function, i.e., the function for calculating the position "L" of the tip end Wa of the wire W, using boundary information that is a plurality of combinations of the laser output value, the current value, and the minimum value of the supply speed in the additive manufacturing apparatus 1 when the tip end Wa of the wire W for the combination of the laser output value and the current value passes through the irradiation area of ​​the laser beam LB without melting.

[0109] 13 is a diagram illustrating an example of a preliminary experiment for determining the relationship between the boundary value of the supply speed, the laser output, and the current value in the additive manufacturing device according to the third embodiment.

[0110] In a preliminary experiment, the processing head 14 was stopped at a position vertically above the position during processing. The additive manufacturing device 1 irradiated the laser beam LB at an arbitrary laser output while the processing head 14 was kept stationary, and supplied the wire W toward the laser beam LB. Figure 13 shows the state in which the wire W was supplied in two cases where the laser output command value and current command value were set to certain values ​​and the supply speed command value was set to different values. In case (b) of Figure 13, the supply speed was faster than in case (a).

[0111] In case (a), Joule heat from the current is input to the wire W, and the tip Wa of the wire W melts when the wire W enters the laser beam LB but before passing through the laser beam LB. A drop 81 is formed at the tip Wa of the wire W. The additive manufacturing apparatus 1 repeatedly supplies the wire W by gradually increasing the supply speed from case (a) in FIG. 13 . When the supply speed of the wire W exceeds a certain value, as shown in case (b), the wire W passes through the laser beam LB without melting the tip Wa. The supply speed of the wire W when it begins to pass through the laser beam LB is the boundary value. In other words, the boundary value at this time is the minimum value of the supply speed of the wire W when the tip Wa passes through the laser beam LB without melting. In this way, the additive manufacturing apparatus 1 determines boundary values ​​corresponding to the laser output command value and the current command value. Detection results from various sensors can be used to determine whether the wire W has passed through the laser beam LB.

[0112] The additive manufacturing apparatus 1 repeats the above operation for acquiring boundary values ​​multiple times while changing the laser output command value and the current command value. In this way, the additive manufacturing apparatus 1 obtains multiple pairs (P_N, I_N, F_N) of the laser output command value P_N, the current command value I_N, and the boundary value F_N of the supply speed. Here, "N" represents the number of sampling operations for acquiring boundary values, and is an arbitrary integer equal to or greater than 2. The additive manufacturing apparatus 1 stores multiple pairs (P_N, I_N, F_N) as boundary information.

[0113] Here, the position "L" of the tip Wa of each of the plurality of wires W (P_N, I_N, F_N), which is the boundary information, corresponds to the diameter "R" of the laser beam LB and satisfies equation (2). The position calculation unit 401 of the additive manufacturing apparatus 1 calculates the constant "Ki" by the least squares method based on the relationship between the plurality of wires (P_N, I_N, F_N) and equation (2).

[0114] The position calculation unit 401 of the additive manufacturing apparatus 1 calculates the position "L" of the tip end Wa of the wire W by calculation using the calculated constant "Ki." The calculation of the constant "Ki" is performed before processing is performed using a wire W made of a material different from the wire W previously used in the additive manufacturing apparatus 1. The calculation of the constant "Ki" may also be performed during the manufacture of the additive manufacturing apparatus 1. Note that although equation (2) is used here, it is sufficient to use a function that has the same properties as equation (2) in terms of the correspondence between an increase or decrease in "L" due to an increase or decrease in the variables "F," "P," and "I." In one example, an equation such as the following equation (10) may be used instead of equation (2).

[0115] L=K1・F / (K2・P+K3・I 2 )+K4...(10)

[0116] Similar to equation (2), equation (10) has the following properties: When the supply speed "F" is large, "L" is large; When the laser output "P" is large, "L" is small; When the current value "I" is large, "L" is small.

[0117] According to the method of the third embodiment, the position calculation unit 401 calculates the tip position of the wire W based on the physical property values, supply speed, beam output value, and current value of the wire W. In this way, the tip position of the wire W can be calculated from parameters including the supply speed, beam output value, current value, physical property values ​​of the wire W, and the traveling direction of the wire W. In other words, for the wire W and the additive manufacturing device 1 actually used, a constant "Ki" that combines the physical property values ​​of the wire W and machine parameters such as the traveling direction of the wire W can be calculated. The additive manufacturing device 1 can reduce the error of the constant "Ki" with respect to the physical property values ​​of the wire W actually used and the process parameters of the additive manufacturing device 1 actually used. This enables the additive manufacturing device 1 to estimate the position of the tip portion Wa with high accuracy.

[0118] Fourth Embodiment In the fourth embodiment, a method for controlling process parameters by the additive manufacturing apparatus 1 at the start of processing will be described. By controlling the process parameters at the start of processing, which is the time when beam emission begins, it is possible to suppress processing defects such as stub phenomena, sputtering, and insufficient lamination of the molded object at the start of processing. In the fourth embodiment, the same components as those in the first to third embodiments are assigned the same reference numerals, and the description will mainly focus on configurations that differ from the first to third embodiments.

[0119] 14 is a diagram showing an example of the functional configuration of an NC device that controls the additive manufacturing apparatus according to embodiment 4. The NC device in Fig. 14 has a modeling start processing condition adjustment unit 404 added to the functional configuration of the NC device 23 that controls the additive manufacturing apparatus 1 shown in Fig. 3 .

[0120] The feedforward controller 40 further includes a start-of-machining processing condition adjustment unit 404. The start-of-machining processing condition adjustment unit 404 operates to gradually increase at least one of the wire W supply speed, current value, and movement speed of the wire W supply axis for a predetermined time from the start of machining. In this example, the movement speed of the wire W supply axis corresponds to the movement speed of the machining head 14, since the wire nozzle 163 is fixed to the machining head 14. Furthermore, after increasing at least one of the wire W supply speed, current value, and movement speed of the wire W supply axis, the start-of-machining processing condition adjustment unit 404 maintains the supply speed, current value, and movement speed of the wire W supply axis at steady values ​​for a predetermined time.

[0121] 15 and 16 are diagrams showing an example of temporal changes in the command values ​​of the process parameters at the start of processing by the additive manufacturing apparatus according to embodiment 4. The process parameters are the laser output value from the laser oscillator 11, the current value from the power output controller 21, and the supply speed of the wire W and the axial speed of the processing head 14 from the drive controller 22. The axial speed of the processing head 14 corresponds to the movement speed of the supply axis of the modeling material. The current value may be a voltage value. The model is processed using the process parameters "P_fin," "F_fin," "I_fin," and "Fwir_fin," which are steady-state values ​​for the laser output value, supply speed, current value, and axial speed, respectively.

[0122] FIG. 15 illustrates an example of temporal changes in process parameters when processing is performed by issuing output commands for "P_fin," "F_fin," "I_fin," and "Fwir_fin" as the process parameter values ​​for the laser output value, feed rate, current value, and axis speed at the start of processing. FIG. 16 illustrates temporal changes in process parameters when issuing an output command for "P_fin" as the process parameter value for the laser output value at the start of processing, and gradually increasing the process parameter values ​​for the feed rate, current value, and axis speed from the start of processing to "F_fin," "I_fin," and "Fwir_fin." Furthermore, after gradually increasing the process parameter values ​​for the feed rate, current value, and axis speed, the feed rate, current value, and axis speed are maintained in a steady state for a predetermined time. Note that, in FIG. 16 , the process parameter that is gradually increased may be at least one of the feed rate, current value, and axis speed. In this case, the process parameter that is not gradually increased may be a value that processes the object at the start of processing. When a plurality of process parameters are gradually increased, the times at which they reach the values ​​required to process the object do not have to be simultaneous. The laser output may also be gradually increased.

[0123] FIG. 17 is a diagram showing another example of temporal changes in the command values ​​of the process parameters at the start of processing by the additive manufacturing device according to embodiment 4. Step S11 shows the start of processing. In step S11, an output command is issued so that the laser output value becomes "P_ini". It is desirable that the value of "P_ini" is a condition under which the supply speed is "F_ini" and the stub phenomenon and drop phenomenon do not occur. It is desirable that "P_ini" is between 1 / 2 and 2 / 3 of "P_fin". In step S11, the other process parameters remain at "0".

[0124] In step S12, the laser output, supply speed, current, and shaft speed are gradually increased. The laser output heats the molten modeling material, which has already begun to be deposited on the workpiece. To prevent the build material from dropping, the supply speed is commanded to the value of "F_ini" and gradually increases from "F_ini," while the build material is supplied to the workpiece. While the value of "F_ini" depends on the physical properties of the modeling material and the process parameters, it is desirable for it to be between 1 / 10 and 1 / 2 of "F_fin." The laser output is gradually increased from "P_ini," and the current and shaft speed are gradually increased from "0."

[0125] In step S13, the current value reaches "I_fin." In step S14, the gradually increased supply speed, axial speed, and laser output reach "F_fin," "Fwir_fin," and "P_fin," respectively. The current value reaches "I_fin" before the supply speed and axial speed, which are the process parameters of the object, reach "F_fin" and "Fwir_fin," respectively, thereby suppressing the stub phenomenon in which the position of the tip Wa of the object collides with the workpiece relative to the supply speed.

[0126] In this way, the processing condition adjustment unit 40 at the start of manufacturing may maintain the laser output value at a value lower than the steady-state value with the supply speed, current value, and movement speed of the supply axis of the wire W set to 0 at the start of processing, and then gradually increase the laser output value, supply speed, current value, and movement speed of the supply axis of the wire W to the steady-state value.

[0127] FIG. 18 is a schematic diagram illustrating an example of how a model is formed when the process parameters are changed over time as shown in FIG. 15 at the start of processing by the additive manufacturing apparatus according to the fourth embodiment. FIG. 18 illustrates the state at the start of processing when the process parameters are output according to the time variations shown in FIG. 15 . The wire W is supplied to the substrate 91, which is the workpiece, and the laser beam LB is irradiated onto the tip Wa of the wire W. Current is conducted to the wire W from the power supply 19, and Joule heat is introduced into the wire W. If the current value "I_fin" is output at the start of processing, a sudden current flows through the wire W, generating a burst current. The burst current generates spatter 85, in which molten modeling material scatters between the wire W and the workpiece. The spatter 85 affects the processing quality of the workpiece. Furthermore, if the supply speed "F_fin" is output at the start of processing, the wire W is just beginning to melt at the start of processing, causing a stub phenomenon in which the tip Wa of the wire W collides with the workpiece. Furthermore, if the axis speed is output as "Fwir_fin" at the start of processing, the wire W is difficult to melt at the start of processing, resulting in processing in which the width and height of the laminated object at the start of processing are smaller than other parts. In this way, outputting process parameters as processing values ​​for the object at the start of processing in the additive manufacturing device 1 affects the processing quality of the object.

[0128] FIG. 19 is a schematic diagram illustrating an example of how a model is formed when the process parameters are changed over time as shown in FIG. 16 at the start of processing by the additive manufacturing apparatus according to the fourth embodiment. FIG. 19 illustrates the state at the start of processing when the process parameters are output according to the time changes shown in FIG. 16. The wire W is supplied to the substrate 91, which is the workpiece, and the laser beam LB is irradiated onto the tip Wa. From the start of processing, the current value is gradually increased to "I_fin" to input heat to the wire W by Joule heating. By gradually increasing the current, a large current is prevented from flowing between the wire W and the workpiece, thereby suppressing spatter 85. From the start of processing, the supply speed is gradually increased to "F_fin." By gradually increasing the supply speed, it is possible to suppress the stub phenomenon, in which the tip Wa of the wire W at the starting end of the model before melting collides with the workpiece. From the start of processing, the axis speed is gradually increased to "Fwir_fin." By gradually increasing the axial speed, it is possible to stack a laminate of sufficient width and height close to that in the steady state at the starting end where the melting position of the wire W has not yet reached the steady state and the melting rate of the modeling material is lower than that in the steady state of processing. In this way, by gradually increasing the current value, feed rate, and axial speed at the start of processing with the additive manufacturing device 1, it is possible to maintain the processing quality of the model.

[0129] According to the fourth embodiment, the start-of-modeling processing condition adjustment unit 404 of the additive manufacturing apparatus 1 controls at least one of the process parameters, namely, the supply speed, the current value, and the movement speed of the supply axis of the wire W, to gradually increase for a predetermined time from the start of processing. By controlling the process parameters at the start of processing, it is possible to prevent the occurrence of a stub phenomenon caused by the modeling material not being melted at the start of processing, and to prevent processing defects such as the height and width of the model at the starting end being smaller than other locations, or the occurrence of spatter 85 due to a sudden current.

[0130] Embodiment 5 In Embodiments 1 to 4, even if the position of the machining reference point RP is controlled, the wire W may collide with the bead 93 depending on the shape of the workpiece or the movement direction of the machining reference point RP. In Embodiment 5, a method for detecting the collision and controlling the process parameters when the wire W collides with the bead 93 will be described. In Embodiment 5, the same components as those in Embodiments 1 to 4 above will be assigned the same reference numerals, and the description will mainly focus on configurations that differ from those in Embodiments 1 to 4.

[0131] FIG. 20 is a diagram illustrating an example of how a bead is formed by the additive manufacturing apparatus according to the fifth embodiment. The additive manufacturing apparatus 1 further includes a load detection unit 26 attached to the wire nozzle 163. The load detection unit 26 detects a load force applied to the wire W from the workpiece. The load force may be a force, moment, pressure, strain, or the like applied to the wire W. An example of the load detection unit 26 is a force sensor that measures force and moment, or a strain gauge that detects strain in the wire nozzle 163. The tip Wa of the wire W collides with the workpiece, for example, the substrate 91, and a load force of force and moment is applied to the wire W. The load force applied to the wire W is transmitted to the load detection unit 26 through the wire nozzle 163, and the load detection unit 26 detects the load force. The load detection unit 26 can detect not only the load force applied to the tip Wa, but also the force and moment applied to the wire W. In one example, when spatter 85 adheres to the side of the wire W during processing or when the workpiece comes into contact with the wire W, force and moment are applied from the wire W to the wire nozzle 163, which can be detected by the load detection unit 26.

[0132] Figure 20 shows what happens when the wire W feed rate is high, the laser output is low, or the current value is low. In Figure 20, because the wire W feed rate is high, or the laser output or current value is low, and the heat input is small, the position of the tip Wa of the wire W collides with the workpiece, causing a stub phenomenon. Figure 20 (a) shows the state of machining before the stub phenomenon occurs, and (b) shows the state of machining after the stub phenomenon occurs. In the machining state of (b), the tip position of the wire W collides with the workpiece, so the load detection unit 26 detects the load force at the tip position.

[0133] 21 is a diagram showing an example of the load force detected by the load detection unit before and after the stub phenomenon occurs. In this diagram, the horizontal axis represents time, and the vertical axis represents the load force. Assuming that the stub phenomenon occurs at time t10, after the stub phenomenon occurs, the load detection unit 26 detects the load force applied to the tip Wa of the wire W. In this way, when the stub phenomenon occurs during processing, the additive manufacturing device 1 can detect contact between the tip Wa of the wire W and the workpiece using the load detection unit 26.

[0134] 22 is a diagram showing an example of the functional configuration of an NC device that controls the additive manufacturing apparatus according to embodiment 5. In Fig. 22, a stub suppression correction unit 42 is added to the functional configuration of the NC device 23 that controls the additive manufacturing apparatus 1 shown in Fig. 3.

[0135] The NC device 23 further includes a stub suppression correction unit 42 that controls at least one of the laser output value, the supply speed, and the current value based on the input load force. The load force detected by the load detection unit 26 is input to the stub suppression correction unit 42. Specifically, the stub suppression correction unit 42 calculates correction amounts for the laser output command, the supply command, and the current command based on the input load force. In one example, the stub suppression correction unit 42 may calculate the correction amount for at least the supply command. The stub suppression correction unit 42 inputs the calculation result of the correction amount to the adder 41. The stub suppression correction unit 42 may calculate the correction amount for at least one of the laser output command, the supply command, and the current command, but for commands for which no correction amount is calculated, the correction amount may be treated as zero.

[0136] The adder 41 adds a correction amount to each of the laser output command, supply command, and current command output by the bead shape controller 39. The adder 41 outputs the process parameters of the controlled laser output value, supply speed, and current value to the laser output controller 12, the wire supply driver 222, and the power supply output controller 21, respectively. The stub suppression correction unit 42 and the adder 41 correspond to a stub suppression correction processing unit that controls at least one of the laser output value, supply speed, and current value based on the load force detected by the load detection unit 26.

[0137] The correction amount output by the stub suppression correction unit 42 is determined based on the load force detected by the load detection unit 26. In one example, the formula for calculating the laser output from the load force is given by the following formula (11).

[0138] DP=-K_dp×Force...(11)

[0139] Here, "DP" means the correction amount of the laser output. "Force" means the load force. "K_dp" means the proportionality constant used when calculating the correction amount of the laser output. The load force "Force" is the force applied by the load detection unit 26 in the direction of the wire W from the position of the tip Wa toward the wire nozzle 163. A positive value is input into "K_dp" if a stub phenomenon is observed during machining. Also, 0 may be input into "K_dp" if no stub phenomenon is observed during machining. The equations for calculating the supply speed and current value from the load force are shown by the following equations (12) and (13), respectively.

[0140] DF=-K_ff×Force...(12) DI=K_if×Force...(13)

[0141] Here, "DF" and "DI" indicate the correction amounts for the supply speed and current value, respectively. "K_ff" and "K_if" indicate proportional constants used when calculating the correction amounts for the supply speed and current value, respectively. If a stub phenomenon is observed during machining, positive values ​​are input to "K_ff" and "K_if." Furthermore, if a stub phenomenon is not observed during machining, 0 may be input to "K_ff" and "K_if." The stub suppression and correction unit 42 may use at least one of equations (11) to (13).

[0142] In the fifth embodiment, the load detection unit 26 detects the load force acting on the wire W, and the stub suppression correction unit 42 calculates a correction amount for correcting at least one of the laser output command, the supply command, and the current command based on the detected load force. Then, the adder 41 adds the calculated correction amount to at least one of the laser output command, the supply command, and the current command output from the bead shape controller 39. This makes it possible to detect the stub phenomenon and adjust the machining conditions after the stub phenomenon is detected. In other words, after the stub phenomenon is detected, it becomes possible to control the machining conditions so that the position of the tip Wa of the wire W falls within the tip position maintenance range.

[0143] The operations of the machining condition adjustment unit 403, the start-of-modeling machining condition adjustment unit 404, the stub suppression correction unit 42, etc. may be performed by different devices for each component, or the operations of multiple components may be performed by a single device at the same time or at different times. For example, the start-of-modeling machining condition adjustment unit 404 may be configured by the same device as the position calculation unit 401, the machining condition adjustment unit 403, etc., or each component may be configured by a different device. Note that the above-mentioned devices may be devices including a processor, a memory, or an electronic computer that integrates these.

[0144] Next, a description will be given of the hardware configuration of the NC device 23. The functions of the NC device 23 are realized by executing a control program, which is a program for controlling the additive manufacturing apparatus 1, using hardware.

[0145] Fig. 23 is a block diagram showing an example of the hardware configuration of an NC unit included in the additive manufacturing apparatuses according to embodiments 1 to 5. The NC unit 23 includes a CPU 301 that executes various processes, a RAM 302 that includes a data storage area, a ROM 303 that is a non-volatile memory, a storage device 304, and an input / output interface 305 for inputting information to the NC unit 23 and outputting information from the NC unit 23. The components shown in Fig. 23 are connected to each other via a bus 306.

[0146] The CPU 301 executes a program stored in the ROM 303 or the storage device 304. The overall control of the layered manufacturing apparatus 1 by the NC device 23 is realized using the CPU 301.

[0147] The storage device 304 is a hard disk drive (HDD) or a solid state drive (SSD). The storage device 304 stores control programs and various data. The ROM 303 stores software or programs that control hardware, such as a boot loader such as a Basic Input / Output System (BIOS) or Unified Extensible Firmware Interface (UEFI), which are programs for basic control of the computer or controller that is the NC device 23. The control programs may also be stored in the ROM 303.

[0148] The programs stored in the ROM 303 and the storage device 304 are loaded into the RAM 302. The CPU 301 deploys the control programs in the RAM 302 and executes various processes. The input / output interface 305 is an interface for connecting the NC device 23 to devices external to the NC device 23. The input / output interface 305 receives the machining program 31, CAD data, etc., and outputs various commands. The NC device 23 may have input devices such as a keyboard and a pointing device, and an output device such as a display.

[0149] The control program may be stored in a computer-readable storage medium. The NC unit 23 may store the control program stored in the storage medium in the storage device 304. The storage medium may be a portable storage medium such as a flexible disk, or a flash memory such as a semiconductor memory. The control program may be installed in the computer or controller that becomes the NC unit 23 from another computer or server device via a communication network.

[0150] The functions of the NC device 23 may be realized by a processing circuit, which is dedicated hardware for controlling the additive manufacturing apparatus 1. The processing circuit is a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination thereof. Some of the functions of the NC device 23 may be realized by dedicated hardware, and other parts may be realized by software or firmware.

[0151] The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies, or different embodiments may be combined with each other. It is also possible to omit or modify parts of the configurations as long as they do not deviate from the gist of the invention.

[0152] 1 Additive manufacturing device, 11 Laser oscillator, 12 Laser output controller, 13 Fiber cable, 14 Processing head, 15 Gas flow regulator, 16 Building material supply unit, 17 Rotating member, 18 Rotation mechanism, 19 Power supply, 20 Conductor, 21 Power output controller, 22 Drive controller, 23 NC device, 24 Bead state detection unit, 25 Displacement amount measurement unit, 26 Load detection unit, 31 Processing program, 32 Program analysis unit, 33 Processing condition table storage unit, 34 Processing condition setting unit, 35 Axis command generation unit, 36 Laser command generation unit, 37 Supply command generation unit, 38 Power command generation unit, 39 Bead shape controller, 40 Feedforward controller, 41 Adder, 42 Stub suppression correction unit, 81 Drop, 82 Link, 85 Spatter, 91 Base material, 93, 93a, 93b Bead, 94 Molten bead, 96 molten pool, 161 wire spool, 162 rotary motor, 163 wire nozzle, 221 head drive unit, 222 wire supply drive unit, 223 stage drive unit, 401 position calculation unit, 402 correction amount calculation unit, 403 processing condition adjustment unit, 404 processing condition adjustment unit at the start of molding, 931 recess, C center line, G shielding gas, IP incident point, LB laser beam, RP processing reference point, W wire, Wa tip.

Claims

1. An additive manufacturing device comprising: a beam heat source supply unit that outputs a beam that melts a modeling material; a current supply unit that applies current to the modeling material; a modeling material supply unit that supplies the modeling material to a workpiece; and a bead shape control unit that acquires bead state information that indicates the state of a base bead of the modeling material that has been melted and solidified on the workpiece by Joule heat caused by irradiation of the beam and current flow, and controls at least one of the output value of the beam, the current value when current is flowed, and the supply speed of the modeling material according to the bead state information so that a new bead formed on the base bead has a predetermined height and width.

2. The additive manufacturing device described in claim 1, further comprising a position calculation unit that calculates the tip position, which is the position of the part of the manufacturing material whose temperature has reached the melting point of the manufacturing material due to Joule heat caused by irradiation of the beam and current flow, based on the supply speed of the manufacturing material, the output value of the beam, and the current value when current is flowing.

3. The additive manufacturing device described in claim 2, further comprising a correction unit that controls the position of a processing reference point, which is the intersection of the center line of the beam output from the beam heat source supply unit and the direction of travel of the manufacturing material supplied from the manufacturing material supply unit, at least in the stacking direction, which is the direction in which the bead is stacked on the workpiece, and the correction unit controls the position of the processing reference point based on the tip position calculated by the position calculation unit.

4. An additive manufacturing device as described in claim 2 or 3, characterized in that it further comprises a processing condition adjustment processing unit that controls at least one of the supply speed, the beam output value, and the current value based on the tip position calculated by the position calculation unit so that the position of the tip of the manufacturing material falls within the irradiation range of the beam.

5. The additive manufacturing device described in any one of claims 2 to 4, characterized in that the position calculation unit calculates the tip position using a function that indicates the relationship between the tip position and the output value, current value, and supply speed of the beam, and calculates constants used in the function using boundary information that is a plurality of combinations of the output value of the beam, the current value, and the minimum value of the supply speed in the additive manufacturing device when the tip of the manufacturing material for this combination of the output value of the beam and the current value passes through the irradiation area of ​​the beam without melting.

6. An additive manufacturing device described in any one of claims 1 to 5, characterized in that it further comprises a manufacturing start processing condition adjustment unit that operates to gradually increase at least one of the supply speed, the current value, and the movement speed of the supply axis of the manufacturing material for a predetermined time from the start of processing.

7. The additive manufacturing device described in claim 6, characterized in that the processing condition adjustment unit at the start of manufacturing gradually increases at least one of the supply speed, the current value, and the movement speed of the supply shaft of the manufacturing material, and then maintains the supply speed, the current value, and the movement speed of the supply shaft of the manufacturing material at steady values ​​for a predetermined period of time.

8. An additive manufacturing device described in any one of claims 1 to 5, further comprising a manufacturing start processing condition adjustment unit that, at the start of processing, maintains the beam output value at a value lower than the steady-state value while setting the supply speed, current value, and movement speed of the supply axis of the manufacturing material to 0, and then gradually increases the beam output value, supply speed, current value, and movement speed of the supply axis of the manufacturing material to the steady-state value.

9. The layered manufacturing device according to any one of claims 1 to 8, further comprising a load detection unit that detects the load force applied from the workpiece to the modeling material.

10. An additive manufacturing device as described in claim 9, further comprising a stub suppression correction processing unit that controls at least one of the beam output value, the supply speed, and the current value based on the load force detected by the load detection unit.

11. An additive manufacturing device as described in any one of claims 1 to 10, characterized in that when the position of the top surface of the base bead is not constant, the bead shape control unit controls the current value without changing the output value of the beam when controlling the height of the new bead.

12. An additive manufacturing method comprising: an energizing step of passing an electric current through a modeling material; a modeling material supply step of supplying the modeling material to a workpiece; a beam irradiation step of irradiating the workpiece with a beam that melts the modeling material; a bead state detection step of detecting the state of a base bead of the modeling material melted and solidified on the workpiece by Joule heat caused by irradiation of the beam and current flow; and a command value control step of controlling at least one of the output value of the beam, the current value during the energizing step, and the supply speed of the modeling material according to the state of the bead so that a new bead formed on the base bead has a predetermined height and width.

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