JP7580682B1 - Additive manufacturing device and additive manufacturing method - Google Patents

Abstract

The additive manufacturing device includes a beam heat source supply unit that outputs a beam that melts the modeling material, a current supply unit that passes current through the modeling material, a modeling material supply unit (16) that supplies the modeling material to a workpiece, and a bead shape control unit that acquires bead state information, which is information indicating the state of a base bead of modeling material 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 passed, and the modeling 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.

Description

The present disclosure relates to an additive manufacturing apparatus and an additive manufacturing method for producing three-dimensional objects.

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

Patent Document 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 Document 1 includes a supply unit that supplies the filler metal to the 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.

International Publication No. 2022/107196

When adjusting the feed rate of the filler metal to control the height of the bead to be constant, it is necessary to adjust the beam power to melt the wire sufficiently. The magnitude of the beam power is positively correlated with the width of the bead, and when controlling the height of the workpiece, there is a problem that the width of the bead does not become constant due to changes in the beam power. In other words, in additive manufacturing, since both the height and width of the bead depend on the beam power, the optimal beam power for obtaining the target bead height and the optimal beam power for obtaining the target bead width may differ. In such a case, in Patent Document 1, it is difficult to keep the bead height and bead width within a certain range from the target value because the beam power conditions cannot be satisfied. In other words, the additive manufacturing device described in Patent Document 1 has a problem in that the width and height of the bead formed during additive manufacturing cannot be controlled simultaneously.

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

In order to solve the above-mentioned problems and achieve the object, the additive manufacturing apparatus of the present disclosure comprises a beam heat source supply unit that outputs a beam that melts the modeling material, a current supply unit that flows an electric current through the modeling material, a modeling material supply unit that supplies the modeling material to a workpiece, a bead shape control unit that acquires bead state information that is information indicating the state of a base bead of modeling material 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 applied, and the modeling material supply speed in accordance with the bead state information so that a new bead formed on the base bead has a predetermined height and width, and a position calculation unit that calculates 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 by Joule heat caused by beam irradiation and current flow, based on the modeling material supply speed, the beam output value, and the current value when current is applied .

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

FIG. 1 is a diagram illustrating an example of a configuration of an additive manufacturing apparatus according to a first embodiment; FIG. 1 is a diagram showing an example of the configuration of a rotation mechanism used in an additive manufacturing apparatus according to a first embodiment; FIG. 1 is a diagram showing an example of the functional configuration of a numerical control (NC) device that controls an additive manufacturing device according to a first embodiment; FIG. 2 is a diagram illustrating a process of forming a model by the additive manufacturing apparatus according to the first embodiment; FIG. 13 is a diagram showing the difference in “L” in two cases where the supply speed, laser output value, and current value are different from each other. FIG. 1 is a diagram for explaining the relationship between the state of processing by the additive manufacturing device according to the first embodiment and the position of the tip of the wire; FIG. 1 is a diagram for explaining a method for controlling a processing reference point in the layered manufacturing apparatus according to the first embodiment; 1 is a flowchart showing an example of an operation procedure for manufacturing a model by the additive manufacturing device according to the first embodiment. FIG. 1 is a schematic diagram showing an example of a laminate in which the height of a bead is controlled by the additive manufacturing device according to the first embodiment; FIG. 13 is a diagram showing an example of the functional configuration of an NC device that controls an additive manufacturing device according to a second embodiment. FIG. 13 is a diagram for explaining how the additive manufacturing apparatus according to the second embodiment controls the position of the tip of the wire. FIG. 13 is a diagram for explaining how the additive manufacturing apparatus according to the second embodiment controls the position of the tip of the wire. FIG. 13 is a diagram for explaining 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. FIG. 13 is a diagram showing an example of the functional configuration of an NC device that controls an additive manufacturing device according to a fourth embodiment. FIG. 13 is a diagram showing an example of a change over time in the command value of the process parameter at the start of processing by the additive manufacturing apparatus according to the fourth embodiment; FIG. 13 is a diagram showing an example of a change over time in the command value of the process parameter at the start of processing by the additive manufacturing apparatus according to the fourth embodiment; FIG. 13 is a diagram showing another example of a change over time in the command value of the process parameter at the start of processing by the additive manufacturing apparatus according to the fourth embodiment; FIG. 16 is a schematic diagram illustrating an example of how a model is formed when 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. 17 is a schematic diagram illustrating an example of how a model is formed when 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. 13 is a diagram for explaining an example of how a bead is formed by the additive manufacturing device according to the fifth embodiment; FIG. 13 is a diagram showing an example of a load force detected by a load detection unit before and after the occurrence of a stub phenomenon. FIG. 13 is a diagram showing an example of the functional configuration of an NC device that controls an additive manufacturing device according to a fifth embodiment. FIG. 1 is a block diagram showing an example of a hardware configuration of an NC device included in an additive manufacturing device according to the first to fifth embodiments.

Below, the additive manufacturing apparatus and additive manufacturing method relating to the embodiments of the present disclosure are described in detail with reference to the drawings.

Embodiment 1.
1 is a diagram showing a schematic diagram of an example of the configuration of an additive manufacturing apparatus according to the first embodiment. The additive manufacturing apparatus 1 is an apparatus having an additive manufacturing technique of the DED type. The additive manufacturing apparatus 1 melts a wire W, which is a modeling 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.

In FIG. 1, the X-axis, Y-axis, and Z-axis are three mutually perpendicular axes. 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.

The additive manufacturing device 1 comprises a laser oscillator 11, a laser output controller 12, a fiber cable 13, a processing head 14, a gas flow regulator 15, a modeling 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.

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 the laser output. The fiber cable 13 propagates the laser beam LB output by the laser oscillator 11 to the processing head 14.

The processing head 14 emits a laser beam LB toward the workpiece. Although not shown, the processing head 14 has a collimating optical system that collimates the laser beam LB and a condensing lens that focuses the laser beam LB inside. 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, for example. When the beam is other than the laser beam LB, the center line is preferably the point where the irradiance is strongest in the irradiance distribution of the beam. The position of the center line may be shifted from the optical axis, the point where the irradiance is strongest, etc., as exemplified above, to the extent that there is no problem in controlling the parameters of the additive manufacturing performed based on the position through which the center line passes. In one example, the center line of the beam can be an axis that passes through the inside of the beam or near the outer periphery of the beam, which is a range determined from the outer periphery of the beam, and is approximately parallel to the traveling direction of the beam.

The processing head 14 is equipped with a gas nozzle that supplies shielding gas G. The additive manufacturing device 1 sprays the shielding gas G toward the workpiece to suppress oxidation of the workpiece and cool the formed bead 93. The bead 93 is formed when the wire W melts and solidifies. 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 the inert gases argon, nitrogen, and carbon dioxide.

The modeling material supply unit 16 supplies wire W, which is a modeling material, to the workpiece, which is the substrate 91 or the 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 back wire W 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 .

The rotating member 17 supports the 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.

The rotating mechanism 18 rotates the rotating member 17. FIG. 2 is a diagram showing an example of the configuration of the rotating mechanism used in the additive manufacturing apparatus according to the first embodiment. The substrate 91 is attached to the rotating member 17. The rotating mechanism 18 rotates the rotating member 17, i.e., the substrate 91 attached to the rotating member 17, around the a-axis or c-axis based on a drive command determined by the stage driving unit 223 described later. Here, the a-axis is perpendicular to the c-axis. When the rotating member 17 rotates, the relative angle and position of the substrate 91 and the processing head 14 change. In FIG. 2, an example is shown in which the rotating mechanism 18 can rotate around the c-axis that passes through the center of the substrate mounting surface, which is the upper surface of the rotating member 17 installed on the rotating mechanism 18, and is perpendicular to the substrate mounting surface, and the a-axis that passes through the intersection of the substrate mounting surface and the c-axis and is provided within the substrate mounting surface. Furthermore, the rotating mechanism 18 may rotate the rotating member 17 based on a drive command. In one example, the rotation mechanism 18 may be configured to be capable of independently rotating the two rotating members 17 in the rotation direction rc with the c-axis as the rotation axis and the rotation direction ra with the a-axis as the rotation axis. The orientation of the a-axis and the 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 be equipped with a servo motor that performs two rotations in the rotation directions ra and rc. By using the rotation mechanism 18, in one example, it becomes possible to perform additive manufacturing of a complex shape that requires a five-axis configuration to access the processing position. In addition, the rotation mechanism 18 may not be required. This is because additive manufacturing using the rotation mechanism 18 is not necessary in the additive manufacturing device 1 that is only intended to perform simple modeling such as a wall or line modeling object.

Returning to FIG. 1, the power source 19 passes a current through the wire W. The two conductors 20 are connected to the positive and negative poles of the power source 19. The two conductors 20 connected to the positive and negative poles are connected to the substrate 91 and the wire nozzle 163, respectively. The current from the power source 19 flows from the positive pole side to the conductor 20, the substrate 91, the workpiece, and 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 connection of the conductor 20 may be such that the conductor 20 connected to the positive pole side is connected to the wire nozzle 163, and the conductor 20 connected to the negative pole side is connected to the substrate 91. The power source 19 and the conductor 20 correspond to a current supply unit that passes a current to the wire W to melt the wire W, which is a modeling material, through the wire W. The power source output controller 21 controls the power source 19 to control the voltage and current of the power source 19. In the following, a case in which the power source output controller 21 controls the current of the power source 19 will be given as an example.

In additive manufacturing, the height and width of the bead 93 both 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 a case, it becomes difficult to keep the height and width of the bead 93 within a certain range from the target value by the laser output condition alone. Therefore, in the first embodiment, heating of the wire W by Joule heat is incorporated so that the height and width of the bead 93 can be controlled independently.

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.

The NC device 23 controls the entire additive manufacturing apparatus 1 in accordance with the 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.

Figure 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 Computer Aided Manufacturing (CAM) device.

The NC device 23 has a program analysis unit 32 that analyzes the machining program 31, a machining condition table memory unit 33 that stores a machining condition table, a machining condition setting unit 34 that sets 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 supply command generation unit 38 that issues a power supply output command.

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 the machining conditions to the machining condition setting unit 34.

The machining condition table storage unit 33 stores a machining condition table in which data on various machining conditions is stored. The machining condition setting unit 34 sets the machining conditions by reading the data on the machining conditions from the machining condition table in accordance with the information for setting the machining conditions. In addition to obtaining data on the specified machining conditions from the data on various machining conditions prestored in the machining condition table, the NC device 23 may obtain data on the machining conditions from the machining program 31 in which the data on the machining conditions is described.

The axis command generating unit 35 generates axis commands, which are a group of interpolation points for each unit time on the movement path, based on the analysis results of the movement path. In the following description, the interpolation points are also referred to as command points. The head driving unit 221 drives the machining head 14 based on the axis commands generated by the axis command generating 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.

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 supply command generating unit 38 generates a power supply output command based on the machining conditions instructed by the machining condition setting unit 34. Here, the power supply output command is a current command.

The NC device 23 has a bead shape controller 39, a feedforward controller 40, and an adder 41. The additive manufacturing device 1 has a bead state detection unit 24 that detects the state of the bead 93. The bead state detection unit 24 is various sensors that acquire bead state information, which is information indicating the state of the bead 93, such as a camera, a thermometer, and a shape measuring device. The bead state detection unit 24 acquires bead state information of the already formed bead 93 that will be the base of the bead 93 to be formed. The state of the bead 93 includes the shape of the bead 93. The detection result by the bead state detection unit 24 is 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 the laser output command value, the supply speed command value, and the current command value based on the detection result by the bead state detection unit 24, i.e., the bead state information.

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 in which the wire W is melted and solidified on the workpiece by Joule heat caused by irradiation of the laser beam LB and current flow, and controls at least one of the laser output value, current value, and wire W supply speed according to the bead state information so that the new bead 93 formed on the base bead 93 has a determined height and width. In one example, the bead shape controller 39 acquires the height of the upper surface of the bead 93 of the base as bead state information, and controls the laser output command value, the supply speed 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 bead 93 of the base. The bead shape controller 39 corresponds to a bead shape control unit. In the case where the direction in which the processing head 14 is moved is the X-axis direction, the height of the bead 93 in the Z-axis direction and the width of the bead 93 in the Y-axis direction are controlled by the bead shape controller 39. The bead state information is the detection result by the bead state detection unit 24. The bead shape controller 39 may control at least one of the laser output command value and the current command value.

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.

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

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

The feedforward controller 40 has 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.

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 generated by irradiation of the laser beam LB and current flow, based on the supply speed of the wire W supplied to the workpiece, the output value of the laser beam LB, and the current value when current is flowing.

Specifically, the position calculation unit 401 calculates the tip position of the wire W before processing is performed based on the supply speed of the wire W, the laser output value from the laser oscillator 11, and the current value from the power 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 after control in the bead shape controller 39, the supply command after control, and the current command after control. The position calculation unit 401 outputs the calculation result of the tip position to the correction amount calculation unit 402. By calculating the tip position of the wire W by the position calculation unit 401, feedforward control can be performed.

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 from the laser oscillator 11, and the current value from the power output controller 21. The tip position of the wire W can be calculated from the values of each processing condition previously stored 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 with 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.

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 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.

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 device 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.

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.

Figure 4 is a schematic diagram showing how a molded object is formed by the additive manufacturing device according to embodiment 1. "θ" in Figure 4 is 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. It is assumed here that the processing head 14 is moving in the X-axis direction.

The intersection of the center line C of the laser beam LB toward the workpiece and the traveling direction of the wire W from the wire nozzle 163 toward the workpiece is the 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 the command point based on the processing program 31.

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

In FIG. 4, "L" is the distance in the X-axis direction from the position of the tip Wa of the wire W fed from the wire nozzle 163, where the temperature reaches the melting point after entering the laser beam LB. In FIG. 4, "L" is 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 is the distance in the traveling direction of the processing head 14. Alternatively, "L" indicates the position of the tip Wa in the traveling direction of the processing head 14, when the position where the wire W projected in the traveling direction 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. Also, the traveling direction of the processing head 14 is referred to as the processing traveling direction.

Figure 5 is a diagram showing the difference in "L" in two cases where the supply speed, laser output value, and current value are different from each other. In the case (a) of Figure 5, "L" is longer than in the case (b). In other words, in the case (a), the supply speed is higher, the laser output value is lower, or the current value is lower than in 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 based on the incident point IP in the processing progress direction.

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

L=f(F,P,I)...(1)

Here, "F" is the command value for the supply speed of the wire W. "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 when the supply speed "F" is large, "L" becomes large, when the laser output "P" is large, "L" becomes small, and when the current value "I" is large, "L" becomes small. The function "f" can be simplified and expressed by the following equation (2).

L=(K1・F)/(K2・P+K3・I) ...(2)

The constants "Ki (i = 1, 2, 3)" used in equation (2) are constants that change 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 device 1. The equation for the function "f" that determines "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.

Next, the relationship between the processing state by the additive manufacturing device 1 and the position of the tip Wa of the wire W will be described. FIG. 6 is a diagram for explaining the relationship between the processing state by the additive manufacturing device according to embodiment 1 and the position of the tip of the wire. FIG. 6 shows a schematic diagram of the processing state in four cases (a) to (d) in which the supply speed, laser output value, or current value are different from each other. In the four cases (a) to (d), the position of the tip Wa in the Z-axis direction is different from each other. In the case (a), the position of the tip Wa is the most vertically upward among the four cases. In FIG. 6, the position of the tip Wa is lowered in the -Z-axis direction in the order of (a), (b), (c), and (d).

In the case of (a), the position of the tip 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 Wa of the wire W. In other words, a drop phenomenon occurs.

In case (b), the position of the tip Wa is in the +Z-axis direction from the molten bead 94. In addition, a link 82 is formed between the position of the tip Wa and the molten bead 94 due to the surface tension of the molten wire W. In such a case, since the position of the tip 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 cut by the influence of external disturbances, etc., case (b) is in a state that is likely to transition to case (a), and the drop phenomenon is likely to occur.

In the case of (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, the drop phenomenon does not occur because contact between the molten wire W and the molten bead 94 is maintained. 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 the case of (c), the additive manufacturing device 1 does not experience either the drop phenomenon or the stub phenomenon, and can continue stable processing.

In the case of (d), the position of the tip Wa is further in the -Z axis direction 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 advances 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), the stub phenomenon occurs.

6(c), the additive manufacturing device 1 can continue stable processing with the tip portion Wa located between the top surface of the molten bead 94 and the bottom surface of the molten pool 96. The additive manufacturing device 1 has difficulty processing when the tip portion Wa is located in the +Z axis direction from the top surface of the molten bead 94 or in the -Z axis direction from the bottom surface of the molten pool 96.

Next, the control of the position of the processing reference point RP by the additive manufacturing device 1 will be described. FIG. 7 is a diagram illustrating a method of controlling the processing reference point in the additive manufacturing device according to embodiment 1. FIG. 7(a) shows a schematic representation of 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) shows a schematic representation of 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).

7A, the position of the tip Wa is vertically above the molten bead 94. The position calculation unit 401 receives the laser output command value indicated by the laser output command after control by the bead shape controller 39, the supply speed command value indicated by the supply command after control by the bead shape controller 39, and the 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 Wa based on the above-mentioned formula (1). The position calculation unit 401 outputs the calculation result of the distance "L" to the correction amount calculation unit 402.

The displacement amount "h" in the Z-axis direction from the top surface of the workpiece, in the case of (a) in Figure 7, the top 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 calculation unit 402.

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.

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

ΔZ=-h-(R/2)tanθ+L・tanθ...(3)

The correction amount calculation unit 402 calculates the correction amount "ΔZ" based on the formula (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 according to the axis command after control, the position of the machining reference point RP moves in the -Z axis direction by "ΔZ" from the position in the state shown in (a) of FIG. 7. By moving the position of the machining reference point RP, the position of the tip Wa comes into contact with the molten bead 94, as shown in (b) of FIG. 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 Wa comes into contact with the upper surface of the substrate 91 or the molten bead 94.

In this way, the additive manufacturing device 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 Wa of the wire W. Even if the process parameters change during processing, the additive manufacturing device 1 can bring the position of the tip Wa into contact with the molten bead 94 by controlling the position of the processing reference point RP. In addition, the occurrence of the stub phenomenon and the drop phenomenon can be suppressed by correcting the position of the tip Wa of the wire W during processing. In other words, the additive manufacturing device 1 can maintain a state in which stable processing is possible by constantly bringing the position of the tip Wa into contact with the molten bead 94.

Next, the procedure of the additive manufacturing method in which the additive manufacturing device 1 according to embodiment 1 manufactures a molded object will be described. Figure 8 is a flowchart showing an example of the operation procedure in manufacturing a molded object by the additive manufacturing device according to embodiment 1.

First, the additive manufacturing device 1 energizes the wire W, which is the modeling material (step S1). The additive manufacturing device 1 energizes the wire W by passing a current from the power source 19 in accordance with a current command. The process of step S1 corresponds to the energization process.

Next, the additive manufacturing device 1 supplies the wire W, which is the 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 according to the supply command. The process of step S2 corresponds to the modeling material supply process.

Thereafter, the additive manufacturing device 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 in which the workpiece is irradiated with a beam that melts the modeling material. In this way, the additive manufacturing device 1 melts the supplied wire W with the laser beam LB to form a bead 93.

Next, the state of the bead 93 is detected by the bead state detection unit 24 (step S4). The process of step S4 corresponds to a bead state detection process for detecting the state of the base bead 93 in which the wire W is melted and solidified on the workpiece by Joule heat due to irradiation of the laser beam LB and energization. Then, the additive manufacturing device 1 controls at least one of the current command value, the laser output command value, and the supply speed command value based on the detection result so that the height and width of the bead 93 are desired (step S5). The process of step S5 corresponds to a command value control process for controlling at least one of the output value of the laser beam LB, the current value during energization, and the supply speed of the wire W so that the new bead 93 formed on the base bead 93 has a determined height and width according to the state of the bead.

Next, the additive manufacturing device 1 calculates the position of the tip Wa of the wire W based on the current command value after control in step S5, the laser output command value after control, and the supply speed command value after control (step S6). The process of step S6 is a position calculation process that calculates 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, based on the supply speed of the modeling material supplied to the workpiece, the output value of the beam, and the current value when current is flowing. In step S6, the additive manufacturing device 1 estimates the position of the tip Wa during processing.

Then, the additive manufacturing device 1 controls the position of the processing reference point RP based on the calculation result of the position of the tip Wa in step S6 (step S7). The process of step S7 is a position control process that controls 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, at least in the stacking direction in which the bead 93 formed by melting and solidifying the wire W is stacked. In this position control process, 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 device 1 repeats the operation of forming the bead 93 while controlling at least one of the current value, the laser output value, and the supply speed so as to obtain the desired height and width of the bead 93 and controlling the position of the processing reference point RP. The additive manufacturing device 1 manufactures a three-dimensional object by stacking the beads 93 on the substrate 91.

Next, we will explain the effect when the additive manufacturing device 1 according to embodiment 1 controls the height of the bead 93. Figure 9 is a schematic diagram showing an example of a laminate in which the height of the bead is controlled by the additive manufacturing device according to embodiment 1.

Figure 9 (a) is a horizontal view of the molded object when bead 93b is layered vertically above bead 93a. Bead 93b is layered on top of bead 93a. Bead 93a has a recess 931 on its upper surface. When processing bead 93b, the shape of bead 93a is measured, and the bead shape controller 39 issues output commands for the supply speed of wire W, the laser output value of laser beam LB, and the current value of power supply 19, which are controlled based on the measurement results so as to keep the height of bead 93b from the upper surface of substrate 91 constant. The workpiece, which is bead 93, is measured by a sensor such as a laser displacement meter.

Since the height of the bead 93 is positively correlated with the magnitude of the supply speed of the wire W, when it is desired to increase the height of the bead 93, the bead shape controller 39 outputs a supply command to increase the supply speed. However, if the supply speed of the wire W is high, the stub phenomenon occurs. For this reason, 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 source 19 to input heat to the wire W. This makes it possible to suppress the occurrence of the stub phenomenon while increasing the supply speed of the wire W. Also, when it is desired to decrease the height of the bead 93, the bead shape controller 39 outputs a supply command to decrease the supply speed. However, if the supply speed of the wire W is low, the drop phenomenon occurs. For this reason, 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 source 19 to input heat to the wire W. This makes it possible to suppress the occurrence of the drop phenomenon while decreasing the supply speed of the wire W.

9B is a vertical view of the bead 93b formed when the laser output is changed along with the magnitude of the supply speed when controlling the height of the bead 93b. In other words, the current value is not changed here. The width of the bead 93 is positively correlated with the magnitude of the laser output. The bead shape controller 39 outputs the laser so as not to cause the stub phenomenon and the drop phenomenon when controlling the height of the bead 93b, so that the width of the bead 93 is not constant. In FIG. 9A, the bead 93b is formed on the bead 93a having a recess 931 on the upper surface. The recess 931 gradually becomes deeper, and after reaching the bottom of the recess 931, the depth gradually becomes shallower. Therefore, when forming the bead 93b on the recess 931, the supply speed is adjusted so as to gradually increase the height of the bead 93b and gradually decrease the height of the bead 93b. In addition, 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 larger than the width W1 of the other portion.

9(c) is a vertical view of the bead 93b formed when the current value of the power source 19 is changed together with the magnitude of the supply speed when controlling the height of the bead 93. In other words, the laser output is not changed here. The width of the bead 93 has little correlation with the magnitude of the current. If the current value is changed without changing the laser output when controlling the height of the bead 93b, it is possible to keep the width of the bead 93 constant. In other words, even if the current value is reduced in the portion other than the recess 931 of the bead 93a or increased in the recess 931, the width W1 of the bead 93b can be made almost constant in the extension direction. Furthermore, since the supply speed is controlled depending on the location as shown in (a) above while keeping the width W1 of the bead 93 constant, it is possible to keep the height of the bead 93 at an arbitrary size. In this way, by controlling the current value of the power source 19 with the bead shape controller 39, it is possible to arbitrarily control the position of the tip Wa of the wire W.

As described above, in the additive manufacturing device 1 that melts the wire W by the Joule heat of the electric current in addition to the laser beam LB, the width of the bead 93 can be kept uniform by controlling not only the laser output value but also the current value when controlling the height of the bead 93. In addition, by using not only the laser beam LB but also the 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 suppressed, and a cheaper laser oscillator 11 can be used. In addition, when the position of the upper surface of the bead 93a that serves as the base is not constant and has unevenness, the tip position of the wire W can be arbitrarily adjusted without sacrificing the width and height of the bead 93 by controlling the current value instead of the laser output value in order to melt the wire W when controlling the height of the bead 93, that is, by controlling the current value without changing the laser output value.

According to the first embodiment, the additive manufacturing device 1 performs processing to melt the modeling material supplied to the workpiece by irradiation of a beam and Joule heat of a current. By adding heat input by Joule heat of a current in addition to irradiation of a beam to the heating of the modeling material, the width of the bead 93 can be processed to be constant by controlling the current value instead of the laser output when controlling the height of the workpiece. In addition, the additive manufacturing device 1 can estimate the position of the tip Wa of the modeling material during processing in the processing to melt the modeling material supplied to the workpiece by irradiation of a beam and Joule heat of a current. Furthermore, the additive manufacturing device 1 can control the position of the processing reference point RP in the stacking direction based on the calculation result of the position of the tip Wa, thereby making it possible to position the tip Wa of the wire W between the bottom surface of the molten pool 96 and the upper surface of the molten bead 94, and maintain a state in which stable processing is possible. Furthermore, since the position of the tip of the modeling material during processing can be calculated from the laser output command value, the current command value, and the supply speed command value of the wire W, the tip position can be calculated in real time within a short period of time. Here, real time means that the calculation is performed simultaneously or instantly within a short period of time, and the position of the processing reference point RP and the like are controlled based on the calculated tip position, and the processing state is controlled, and the time is short enough that this control is not hindered. As a result, the additive manufacturing device 1 can perform feedforward control.

Embodiment 2
In the second embodiment, 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 and perform processing. In the second embodiment, the same components as those in the first embodiment are given the same reference numerals, and configurations different from those in the first embodiment will be mainly described.

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

The feedforward controller 40 has a processing condition adjustment unit 403. The processing condition adjustment unit 403 receives the calculation result of the position of the tip Wa of the wire W, a supply command, a laser output command, and a current command. The processing condition adjustment unit 403 calculates at least one correction amount 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 Wa of the wire W falls within the irradiation range of the laser beam LB. The processing condition adjustment unit 403 inputs the calculation result of the correction amount to the adder 41. The processing condition adjustment unit 403 only needs to calculate at least one correction amount of the supply speed, the laser output value, and the current value, but for those for which the correction amount has not been calculated, the correction amount can be treated as 0.

The adder 41 is also added after the bead shape controller 39. The adder 41 adds a correction amount to each of the controlled supply command, controlled laser output command, and controlled current command output by the bead shape controller 39. The adder 41 outputs the process parameters of the added controlled supply speed, laser output value, and current value to the laser output controller 12, wire supply drive unit 222, and power 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 Wa of the modeling material falls within the beam irradiation range.

11 and 12 are diagrams for explaining how the additive manufacturing apparatus according to the second embodiment controls the position of the tip of the wire. In FIG. 11 and FIG. 12, a tip position maintenance range, which is a range in which 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 within the irradiation range of the laser beam LB. In the irradiation range of the laser beam LB on a surface including the processing direction and the wire W traveling direction, if the position of the incident point IP in the processing direction, in this example the X-axis direction, is set to 0, the tip position maintenance range is a range from "TL" to "TH". "TL" and "TH" are values that are greater than 0 and smaller than the diameter "R" of the laser beam LB. In processing, if the position "L" of the tip Wa in the processing direction based on 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 when the position of the tip Wa is likely to deviate from the irradiation range to the wire nozzle 163 side. In addition, in machining, if the position "L" of the tip Wa in the machining progress direction based on the incident point IP is larger 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 a 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.

Figure 11 (a) 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 control, as shown in (b), the position "L" of the tip Wa becomes smaller than the threshold value "TH".

If "L" after control in the processing condition adjustment unit 403 is taken as "L1a", and "F" before control when only the supply speed value "F" of the process parameter is controlled is taken as "F1", and "F" after control is taken as "F1a", the correction value of "F" is expressed by the following equation (4) using equation (2).

F1a-F1=L1a・(K2・P1+K3・I1)/K1−F1...(4)

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 going out of the irradiation range of the laser beam LB.

Next, we will explain the case where only the laser output value "P" of the process parameter is controlled. 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 formula (5) using formula (2).

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

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 going out of the irradiation range of the laser beam LB.

Next, a case where only the current value "I" of the process parameter is controlled will be described. If "I" after control when only the current value "I" of the process parameter is controlled is set to "I1a", the correction value of "I" is expressed by the following equation (6) using equation (2).

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

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 going out of the irradiation range of the laser beam LB.

Figure 12 (a) 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 control, as shown in (b), the position "L" of the tip Wa becomes larger than the threshold value "TL".

If "L" after control in the processing condition adjustment unit 403 is taken as "L2a", and "F" before control when only the supply speed value "F" of the process parameter is controlled is taken as "F2", and "F" after control is taken as "F2a", the correction value of "F" is expressed by the following equation (7) using equation (2).

F2a-F2=L2a・(K2・P2+K3・I2)/K1-F2...(7)

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", the position of the tip Wa falls within the tip position maintenance range, and it is prevented from going out of the irradiation range of the laser beam LB.

Next, we will explain the case where only the laser output value "P" of the process parameter is controlled. 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).

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

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", the position of the tip Wa falls within the tip position maintenance range, and is prevented from moving out of the irradiation range of the laser beam LB.

Next, a case where only the current value "I" of the process parameter is controlled will be described. If "I" after control when only the current value "I" of the process parameter is controlled is set to "I2a", the correction value of "I" is expressed by the following equation (9) using equation (2).

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

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 greater than the threshold value "TL", the position of the tip Wa falls within the tip position maintenance range, and is prevented from moving out of the irradiation range of the laser beam LB.

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 supply speed, and the current value, but two or three of the laser output value, the supply 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 supply 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 supply speed, and the current value.

According to the second embodiment, the additive manufacturing device 1 is capable of controlling the process parameters based on the position "L" of the tip 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 is possible to maintain the position of the tip Wa within the irradiation range of the laser beam LB and perform processing. In addition, in order to prevent the tip position of the wire W from being outside the irradiation range of the laser beam LB due to an increase or decrease in the supply speed of the wire W, it is possible to adjust the supply speed and at least one of the laser output value and the current value to keep the tip position of the wire W within the irradiation range of the laser beam LB.

Embodiment 3.
In the first embodiment, the constant "Ki" can be determined by any method. In the third embodiment, a method of determining the constant "Ki" by a preliminary experiment is described. By determining the constant "Ki" based on the results of a preliminary experiment using the modeling material actually used in processing and the additive manufacturing device 1, the additive manufacturing device 1 is able to estimate the position of the tip portion Wa with high accuracy. In the third embodiment, the same components as those in the first and second embodiments are given the same reference numerals, and the configurations different from those in the first and second embodiments are mainly described.

In the third embodiment, the additive manufacturing device 1 obtains the relationship between the boundary value of the supply speed, the laser output value by 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 value. 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. In addition, 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 portion Wa of the wire W, using boundary information that is a combination of the laser output value, the current value, and the minimum value of the supply speed in the additive manufacturing device 1 when the tip portion Wa of the wire W in the combination of the laser output value and the current value passes through the irradiation area of the laser beam LB without melting.

Here, we will explain the preliminary experiment. Figure 13 is a diagram that explains an example of a preliminary experiment to determine the relationship between the boundary value of the supply speed, the laser output, and the current value in an additive manufacturing device according to embodiment 3.

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

In the case of (a), Joule heat of the current is input to the wire W, and the tip Wa of the wire W melts from when the wire W enters the laser beam LB until it passes through the laser beam LB. A drop 81 is formed at the tip Wa of the wire W. The additive manufacturing device 1 repeatedly supplies the wire W by increasing the supply speed from the case of (a) in FIG. 13. When the supply speed of the wire W becomes larger than a certain value, as shown in the case of (b), the wire W passes through the laser beam LB without the tip Wa melting. The supply speed of the wire W when it starts 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 device 1 obtains the boundary value corresponding to the laser output command value and the current command value. The detection results by various sensors can be used to determine whether the wire W has passed through the laser beam LB.

The additive manufacturing device 1 repeats the above operation for obtaining the boundary value multiple times while changing the laser output command value and the current command value. In this way, the additive manufacturing device 1 obtains multiple (P_N, I_N, F_N) pairs of laser output command value P_N, current command value I_N, and supply speed boundary value F_N. Here, "N" represents the number of sampling operations for obtaining the boundary value, and is any integer equal to or greater than 2. The additive manufacturing device 1 holds multiple (P_N, I_N, F_N) as boundary information.

Here, the position "L" of the tip Wa of each of the multiple (P_N, I_N, F_N) wires W, 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 device 1 calculates the constant "Ki" by the least squares method based on the relationship between the multiple (P_N, I_N, F_N) and equation (2).

The position calculation unit 401 of the additive manufacturing device 1 calculates the position "L" of the tip Wa of the wire W by a calculation using the calculated constant "Ki". The calculation of the constant "Ki" is performed before processing is performed using a wire W of a material different from the wire W previously used in the additive manufacturing device 1. The calculation of the constant "Ki" may be performed during the manufacture of the additive manufacturing device 1. Note that although formula (2) is used here, it is sufficient to use a function in which the increase or decrease in "L" due to an increase or decrease in the variables "F", "P", and "I" has the same properties as formula (2) even if formula (2) is not used. In one example, a formula such as the following formula (10) may be used instead of formula (2).

L=K1・F/(K2・P+K3・I ² )+K4...(10)

Equation (10), like equation (2), has the following properties: When the supply speed "F" becomes larger, "L" becomes larger. When the laser output "P" becomes larger, "L" becomes smaller. When the current value "I" becomes larger, "L" becomes smaller.

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 value, the supply speed, the beam output value, and the current value of the wire W. In this way, the tip position of the wire W can be calculated from the parameters including the supply speed, the beam output value, the current value, the physical property value 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 value of the wire W and the mechanical 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" for the physical property value 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 Wa with high accuracy.

Embodiment 4.
In the fourth embodiment, a method for controlling the process parameters at the start of processing by the additive manufacturing apparatus 1 will be described. By controlling the process parameters at the start of processing, which is the time when beam emission starts, it is possible to suppress processing defects such as stub phenomenon, 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 given the same reference numerals, and the configurations different from those in the first to third embodiments will be mainly described.

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

The feedforward controller 40 further includes a start-of-modeling processing condition adjustment unit 404. The start-of-modeling 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 processing. In this example, the movement speed of the wire W supply axis corresponds to the movement speed of the processing head 14, since the wire nozzle 163 is fixed to the processing head 14. In addition, 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-modeling 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.

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

Figure 15 is a diagram showing an example of the change over time of the process parameters when processing is performed by outputting "P_fin", "F_fin", "I_fin", and "Fwir_fin" as the process parameter values of the laser output value, the supply speed, the current value, and the axis speed at the start of processing. Figure 16 is a diagram showing the change over time of the process parameters when outputting "P_fin" as the process parameter value of the laser output value at the start of processing, and outputting the process parameter values of the supply speed, the current value, and the axis speed while gradually increasing them from the start of processing to "F_fin", "I_fin", and "Fwir_fin". In addition, after gradually increasing the values of the process parameters of the supply speed, the current value, and the axis speed, the supply speed, the current value, and the 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 supply speed, the current value, and the 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 at which the object is processed do not have to be simultaneous. Also, the laser output may be gradually increased.

Figure 17 is a diagram showing another example of the change over time in the command values of the process parameters at the start of processing in the additive manufacturing device of 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 in which the supply speed is "F_ini" and no stub or drop phenomenon occurs. It is desirable that "P_ini" is greater than or equal to 1/2 and less than or equal to 2/3 of "P_fin". In step S11, the other process parameters remain at "0".

In step S12, the laser output value, supply speed, current value, and shaft speed are gradually increased. The molten modeling material, which has been heated by the laser output, is beginning to be layered on the workpiece. In order to prevent the drop phenomenon from occurring, the supply speed is commanded to output the value of "F_ini" and gradually increased from "F_ini" while supplying the modeling material to the workpiece. The value of "F_ini" depends on the physical properties of the modeling material and the process parameters, but it is desirable that it is 1/10 or more and 1/2 or less of "F_fin". The laser output value is gradually increased from "P_ini", and the current value and shaft speed are gradually increased from "0".

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

In this way, the processing condition adjustment unit 40 at the start of processing 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 zero 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.

Figure 18 is a schematic diagram illustrating an example of the state of forming a model when the process parameters are changed with the time change shown in Figure 15 at the start of processing of the additive manufacturing device according to embodiment 4. Figure 18 shows the state at the start of processing when the process parameters are output with the time change of Figure 15. The wire W is supplied to the substrate 91, which is the workpiece, and the laser beam LB is irradiated to the tip Wa of the wire W. Current from the power source 19 is conducted to the wire W, and heat is input to the wire W by Joule heat. When the current value "I_fin" is output at the start of processing, a current flows suddenly in the wire W, so a sudden current occurs. The occurrence of the sudden current causes spatters 85, in which the molten modeling material scatters between the wire W and the workpiece. The spatters 85 affect the processing quality of the workpiece. In addition, when the supply speed "F_fin" is output at the start of processing, the wire W is in a state where it is just starting to melt at the start of processing, so a stub phenomenon occurs 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 in a state where it is difficult to melt at the start of processing, and the width and height of the laminated object at the start of processing will be smaller than other parts. In this way, if the process parameters are output as the processing values of the object at the start of processing in the additive manufacturing device 1, it will affect the processing quality of the object.

Figure 19 is a schematic diagram illustrating an example of how a molded object is formed when the process parameters are changed with the time change shown in Figure 16 at the start of processing by the additive manufacturing device according to embodiment 4. Figure 19 shows the state at the start of processing when the process parameters are output with the time change in Figure 16. The wire W is supplied to the substrate 91, which is the workpiece, and the laser beam LB is irradiated to the tip Wa. The current value is gradually increased to "I_fin" from the start of processing, and heat is input to the wire W by Joule heat. By gradually increasing the current, it is possible to suppress a large current flowing through the wire W and the workpiece, and sputtering 85 is suppressed. The supply speed is gradually increased to "F_fin" from the start of processing. By gradually increasing the supply speed, it is possible to suppress the stub phenomenon in which the tip Wa of the wire W before melting at the starting end of the molded object collides with the workpiece. The axis speed is gradually increased to "Fwir_fin" from the start of processing. By gradually increasing the axial speed, a laminate with sufficient width and height close to that in the steady state can be laminated 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, supply speed, 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.

According to the fourth embodiment, the start-of-modeling processing condition adjustment unit 404 of the additive manufacturing device 1 controls at least one of the process parameters, the supply speed, the current value, and the movement speed of the supply axis of the wire W, to be gradually increased 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 parts, and the occurrence of spatters 85 due to sudden current.

Embodiment 5.
In the first to fourth embodiments, 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 moving direction of the machining reference point RP. In the fifth embodiment, a method of detecting the collision and controlling the process parameters when the wire W collides with the bead 93 will be described. In the fifth embodiment, the same components as those in the first to fourth embodiments are denoted by the same reference symbols, and the configurations different from those in the first to fourth embodiments will be mainly described.

Figure 20 is a diagram illustrating an example of how a bead is formed by the additive manufacturing device according to the fifth embodiment. The additive manufacturing device 1 further includes a load detection unit 26 attached to the wire nozzle 163. The load detection unit 26 detects the load force applied to the wire W from the workpiece. The load force is a force, moment, pressure, strain, etc. 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 of 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, a force and moment are applied from the wire W to the wire nozzle 163, which can be detected by the load detection unit 26.

Figure 20 shows the situation when the wire W supply speed is high, the laser output is low, or the current value is low. In Figure 20, because the wire W supply speed 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 the 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.

Figure 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 indicates time and the vertical axis indicates the load force. If we assume 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.

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

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 the correction amount of 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 of 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 of at least one of the laser output command, the supply command, and the current command, but for those commands for which the correction amount has not been calculated, the correction amount may be treated as 0.

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 drive unit 222, and the power 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.

The correction amount output by the stub suppression correction unit 42 is determined by 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 shown by the following formula (11).

DP=-K_dp×Force...(11)

Here, "DP" means the correction amount of the laser output. "Force" means the load force. "K_dp" means the proportional constant 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 to "K_dp" if a stub phenomenon is observed during processing. Also, 0 may be input to "K_dp" if the stub phenomenon is not observed during processing. The equations for calculating the supply speed and current value from the load force are shown by the following equations (12) and (13), respectively.

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

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

In the fifth embodiment, the load detection unit 26 detects the load force applied to 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. The adder 41 then 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 processing conditions after the stub phenomenon is detected. In other words, after the stub phenomenon is detected, it becomes possible to control the processing conditions so that the position of the tip Wa of the wire W falls within the tip position maintenance range.

The operations of the processing condition adjustment unit 403, the start-of-modeling processing condition adjustment unit 404, the stub suppression correction unit 42, etc. may be performed by a different device for each component, or a single device may perform the operations of multiple components at the same time or at different times. In one example, the start-of-modeling processing condition adjustment unit 404 may be configured by the same device as the position calculation unit 401, the processing condition adjustment unit 403, etc., or each component may be configured by a different device. Note that the above-mentioned devices may be devices that include a processor, a memory, or an electronic computer that is an integrated combination of these.

Next, we will explain 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 executing control of the additive manufacturing device 1, using hardware.

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

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

The storage device 304 is a hard disk drive (HDD) or a solid state drive (SSD). The storage device 304 stores a control program and various data. The ROM 303 stores a boot loader such as a basic input/output system (BIOS) or a unified extensible firmware interface (UEFI), which is a program for basic control of the computer or controller that is the NC device 23, and software or a program that controls the hardware. The control program may be stored in the ROM 303.

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

The control program may be stored in a storage medium that can be read by a computer. 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.

The functions of the NC device 23 may be realized by a processing circuit, which is dedicated hardware for controlling the additive manufacturing device 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 of these. The functions of the NC device 23 may be partly realized by dedicated hardware and partly realized by software or firmware.

The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies, or the embodiments may be combined with each other. Also, parts of the configurations may be omitted or modified without departing from the spirit of the invention.

1 Additive manufacturing device, 11 Laser oscillator, 12 Laser output controller, 13 Fiber cable, 14 Processing head, 15 Gas flow rate regulator, 16 Modeling material supply unit, 17 Rotating member, 18 Rotating 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 Sputter, 91 Base material, 93, 93a, 93b Bead, 94 molten bead, 96 molten pool, 161 wire spool, 162 rotation 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 start of molding, 931 recess, C center line, G shielding gas, IP incidence point, LB laser beam, RP processing reference point, W wire, Wa tip portion.

Claims (12)

A beam heat source supply unit that outputs a beam that melts the modeling material;
A current supply unit that supplies a current to the modeling material;
A modeling material supply unit that supplies the modeling material to a workpiece;
a bead shape control unit that acquires bead state information, which is information indicating the state of a base bead formed by melting and solidifying the modeling material on the workpiece by Joule heat caused by irradiation of the beam and energization, and controls at least one of the output value of the beam, the current value during energization, 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;
a position calculation unit that calculates a tip position of a portion of the modeling material whose temperature has reached a melting point of the modeling material due to Joule heat caused by irradiation of the beam and energization, based on a supply speed of the modeling material, an output value of the beam, and a current value during the energization;
An additive manufacturing apparatus comprising: A correction unit controls the position of a processing reference point, which is an intersection of a center line of the beam output from the beam heat source supply unit and a traveling direction of the modeling material supplied from the modeling material supply unit, at least in a stacking direction, which is a direction in which the bead is stacked on the workpiece,
The layered manufacturing apparatus according to claim 1 , wherein the correction unit controls the position of the processing reference point based on the tip position calculated by the position calculation unit. The additive manufacturing apparatus according to claim 1 or 2, further comprising 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. The position calculation unit is
calculating the tip position using a function indicating a relationship between the tip position and the output value, the current value, and the supply speed of the beam;
The additive manufacturing device according to claim 1 or 2, characterized in that the constants used in the function are calculated using boundary information which is a plurality of combinations of the beam output value, the current value, and the minimum value of the supply speed in the additive manufacturing device when the tip of the modeling material for this combination of the beam output value and the current value passes through the beam irradiation area without melting. A beam heat source supply unit that outputs a beam that melts the modeling material;
A current supply unit that supplies a current to the modeling material;
A modeling material supply unit that supplies the modeling material to a workpiece;
a bead shape control unit that acquires bead state information, which is information indicating the state of a base bead formed by melting and solidifying the modeling material on the workpiece by Joule heat caused by irradiation of the beam and energization, and controls at least one of the output value of the beam, the current value during energization, 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;
a start-of-modeling processing condition adjustment unit that operates to gradually increase at least one of the supply speed, the current value, and the moving speed of the supply shaft of the modeling material for a predetermined time from the start of processing ;
An additive manufacturing apparatus comprising : The additive manufacturing apparatus according to claim 5, 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 time. The additive manufacturing device described in claim 1, further comprising a manufacturing start processing condition adjustment unit that maintains the beam output value at a value lower than a steady-state value while setting the supply speed, the current value, and the movement speed of the supply axis of the modeling material to 0 at the start of processing, and then gradually increases the beam output value, the supply speed, the current value, and the movement speed of the supply axis of the modeling material to the steady-state values. The additive manufacturing apparatus according to any one of claims 1 to 7, further comprising a load detection unit that detects a load force applied from the workpiece to the modeling material. The additive manufacturing apparatus according to claim 8, further comprising a stub suppression correction processing unit that controls at least one of the output value of the beam, the supply speed, and the current value based on the load force detected by the load detection unit . The additive manufacturing device described in any one of claims 1, 2, 5, 6 and 7, characterized in that 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 when the position of the top surface of the base bead is not constant. The additive manufacturing apparatus according to claim 9, characterized in that, when the position of the upper 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. A current passing process for passing an electric current through the molding material;
a modeling material supplying 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 process for detecting a state of a bead of the base material formed by melting and solidifying the modeling material on the workpiece by Joule heat caused by irradiation of the beam and energization;
a command value control step of controlling at least one of the output value of the beam, the current value during energization, 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;
a position calculation process for calculating a tip position of a portion of the shaping material whose temperature has reached the melting point of the shaping material due to Joule heat caused by irradiation of the beam and energization based on a supply speed of the shaping material, an output value of the beam, and a current value during the energization;
An additive manufacturing method comprising:

Images