Additive manufacturing apparatus and additive manufacturing method

Abstract

The additive manufacturing apparatus (1) includes a material supply unit (12) that supplies material and a beam source that outputs a beam, a molding unit (2) that forms a molded object by adhering the material melted by the beam to a workpiece (17), and a beam source control unit (21) that generates a beam output command by converting the beam output indicated in the processing conditions into a pulsed beam output, thereby outputting a pulsed beam from the beam source. The additive manufacturing apparatus (1) can reduce the thermal influence in the molding process.

Description

[Technical Field]

[0001] This disclosure relates to an additive manufacturing apparatus and an additive manufacturing method for manufacturing three-dimensional objects. [Background technology]

[0002] Additive Manufacturing (AM) is a well-known technology for manufacturing three-dimensional objects. In Directed Energy Deposition (DED), one of several methods within additive manufacturing, an additive manufacturing apparatus forms beads by supplying material to a commanded position while irradiating the material and the workpiece with a beam. The beads are solidified products obtained when molten material solidifies on the workpiece. The additive manufacturing apparatus manufactures the object by sequentially stacking the beads.

[0003] Patent Document 1 discloses an additive manufacturing apparatus that produces a three-dimensional object by moving the processing point along a path based on a molding plan, adding molten material to the processing point to form a bead, and sequentially stacking layers made of beads. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2024-67332 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] In the DED (Directed Energy Deposition) printing process, the continuous irradiation of the beam onto the workpiece can sometimes result in excessive heat being introduced to the workpiece. Excessive heat input during the printing process can lead to a decrease in the quality of the printed object due to thermal effects such as thermal expansion, thermal contraction, residual stress, and structural changes.

[0006] This disclosure has been made in view of the above, and aims to provide an additive manufacturing apparatus that can reduce the thermal effects in the molding process. [Means for solving the problem]

[0007] To solve the above-mentioned problems and achieve the objective, the additive manufacturing apparatus according to this disclosure has a material supply unit that supplies material toward the processing point of the workpiece and a beam source that outputs a beam, a molding unit that forms a molded object by adhering the material melted by the beam to the workpiece, and processing conditions Included The system includes a beam source control unit that generates a beam output command by converting the beam output into a pulsed beam output, thereby causing the pulsed beam to be output from the beam source. The beam source control unit adjusts the amplitude and pulse width of the pulsed beam output so that the amount of heat in the beam per pulse is sufficient to melt the amount of material to be attached to the processing point. [Effects of the Invention]

[0008] The additive manufacturing apparatus described herein has the effect of reducing the influence of heat in the molding process. [Brief explanation of the drawing]

[0009] [Figure 1] A diagram showing an example configuration of an additive manufacturing apparatus according to Embodiment 1. [Figure 2] Figure 1 for illustrating the determination of pulse waveforms by the beam source control unit of the additive manufacturing apparatus according to Embodiment 1. [Figure 3] Figure 2 illustrates the determination of pulse waveforms by the beam source control unit of the additive manufacturing apparatus according to Embodiment 1. [Figure 4] Figure 1 illustrating the conversion of beam output by the beam source control unit of the additive manufacturing apparatus according to Embodiment 1. [Figure 5] Figure 2 illustrates the conversion of beam output by the beam source control unit of the additive manufacturing apparatus according to Embodiment 1. [Figure 6] Figure 3 for explaining the conversion of beam output by the beam source control unit of the additive manufacturing apparatus according to Embodiment 1 [Figure 7] Figure 1 for explaining the adjustment of the wire supply speed by the material supply control unit of the additive manufacturing apparatus according to Embodiment 1 [Figure 8] Figure 2 for explaining the adjustment of the wire supply speed by the material supply control unit of the additive manufacturing apparatus according to Embodiment 1 [Figure 9] Flowchart showing an example of the processing procedure performed by the control device of the additive manufacturing apparatus according to Embodiment 1 [Figure 10] Figure 1 for explaining the relationship between the beam output and the formed object in the additive manufacturing apparatus according to Embodiment 2 [Figure 11] Figure 2 for explaining the relationship between the beam output and the formed object in the additive manufacturing apparatus according to Embodiment 2 [Figure 12] Figure for explaining the determination of the pulse waveform by the beam source control unit of the additive manufacturing apparatus according to Embodiment 2 [Figure 13] Figure for explaining the conversion of beam output by the beam source control unit of the additive manufacturing apparatus according to Embodiment 2 [Figure 14] Figure showing an example of the configuration of the additive manufacturing apparatus according to Embodiment 3 [Figure 15] Figure for explaining the deceleration section included in the path for moving the processing head in Embodiment 3 [Figure 16] Figure showing an example of the moving speed calculated by the head control unit of the additive manufacturing apparatus according to Embodiment 3 [Figure 17] Figure 1 for explaining the conversion of beam output by the beam source control unit of the additive manufacturing apparatus according to Embodiment 3 [Figure 18] Figure 2 for explaining the conversion of beam output by the beam source control unit of the additive manufacturing apparatus according to Embodiment 3 [Figure 19] Flowchart showing an example of the operation procedure of the additive manufacturing apparatus according to Embodiment 3 [Figure 20] Figure showing the first example of the movement speed calculated by the head control unit of the additive manufacturing apparatus according to Embodiment 4 [Figure 21] Figure showing the second example of the movement speed calculated by the head control unit of the additive manufacturing apparatus according to Embodiment 4 [Figure 22] Figure showing the third example of the movement speed calculated by the head control unit of the additive manufacturing apparatus according to Embodiment 4 [Figure 23] Figure showing a configuration example of the control circuit according to Embodiments 1 to 4 MODE FOR CARRYING OUT THE INVENTION

[0010] Hereinafter, the additive manufacturing apparatus and the additive manufacturing method according to the embodiment will be described in detail based on the drawings.

[0011] Embodiment 1. FIG. 1 is a diagram showing a configuration example of an additive manufacturing apparatus 1 according to Embodiment 1. The additive manufacturing apparatus 1 is a DED type additive manufacturing apparatus. The additive manufacturing apparatus 1 supplies a material to a workpiece 17 and manufactures a shaped object by melting the material using a beam. The shaped object manufactured by the additive manufacturing apparatus 1 is a three-dimensional shaped object made of a metal material.

[0012] The additive manufacturing apparatus 1 includes a shaping unit 2 for forming a shaped object and a control device 3. The control device 3 controls the shaping unit 2 according to a machining program which is a numerical control (NC) program.

[0013] In Embodiment 1, the beam used for melting the material is a laser beam L. For melting the material, an electron beam or the like which is a beam other than the laser beam L, or an arc may be used. In Embodiment 1, the material is a metal wire 15. The material is not limited to the wire 15 and may be a metal powder.

[0014] The molding unit 2 supplies the wire 15 to a position commanded by the control device 3, while irradiating the wire 15 and the workpiece 17 with a laser beam L. The molding unit 2 forms a bead with the material melted by the laser beam L. The bead is formed in the molten pool. The molten pool is a reservoir of molten metal created when the workpiece 17 and the wire 15 melt due to irradiation with the laser beam L.

[0015] Multiple beads are arranged on the substrate to form a layer of beads. By stacking these bead layers, a molded object is formed on the substrate. In this way, the additive manufacturing apparatus 1 manufactures a molded object by stacking bead layers. The substrate on which the molded object is formed is a sheet material. The substrate may be something other than a sheet material. The workpiece 17 is an object to which molten material is added, and includes the substrate and the molded object during the molding process.

[0016] In Embodiment 1, the X, Y, and Z axes are three axes perpendicular to each other. The X and Y axes are two horizontal axes. The Z axis is a vertical axis. In each of the X, Y, and Z axis directions, the direction indicated by the arrow is considered positive, and the direction opposite to the arrow is considered negative. The positive Z direction is assumed to be the vertically upward direction. Layers of beads are stacked in the positive Z direction.

[0017] The molding unit 2 comprises a laser oscillator 11, a material supply unit 12, a processing head 13, and a head drive unit 14. The laser oscillator 11, which is the beam source, outputs a laser beam L. The laser beam L output by the laser oscillator 11 propagates through a fiber optic cable 16, which is an optical transmission path, and enters the processing head 13. An optical system, such as a collimating optical system or a focusing optical system, is arranged inside the processing head 13. In Figure 1, the optical system is not shown. The processing head 13 emits the laser beam L, which has passed through the optical system, toward the workpiece 17.

[0018] The processing head 13 includes a beam nozzle through which the laser beam L passes and a gas nozzle for injecting shielding gas. In Figure 1, the beam nozzle and gas nozzle are not shown. The central axis of the beam nozzle coincides with the optical axis of the optical system. The central axis of the beam nozzle also coincides with the Z-axis. The center line of the laser beam L that irradiates the workpiece 17 coincides with the Z-axis. The laser beam L passes through the optical system inside the processing head 13, through the beam nozzle, and is emitted from the processing head 13.

[0019] The processing point is a point on the workpiece 17 that lies on the central axis of the beam nozzle. The processing point represents both the position where the laser beam L is irradiated and the position where the material is supplied. In the manufacturing process, the molding unit 2 moves the processing point along the path, irradiating the processing point with the laser beam L and supplying the wire 15 to the processing point. The molding unit 2 forms the object by adhering the material melted by the laser beam L to multiple processing points.

[0020] The molding unit 2 injects shielding gas from a gas nozzle toward the workpiece 17. By injecting the shielding gas, the molding unit 2 reduces oxidation of the material and the workpiece 17, and also cools the molded object. An example of a shielding gas is an inert gas such as argon gas.

[0021] The material supply unit 12 supplies wire 15 toward the machining point. The material supply unit 12 has a material supply source and a material supply nozzle that feeds the wire 15 unfurled from the material supply source toward the machining point. In Figure 1, the material supply source and material supply nozzle are not shown. Figure 1 shows an example of a so-called side supply method in which the wire 15 is fed in a direction oblique to the Z axis. The wire 15 may be supplied by a so-called center supply method in which the wire 15 is fed in the Z axis direction, rather than by a side supply method.

[0022] The head drive unit 14 moves the machining head 13 in the X-axis, Y-axis, and Z-axis directions, respectively. For example, the head drive unit 14 includes a servo motor that constitutes an operating mechanism for moving the machining head 13 in the X-axis direction, a servo motor that constitutes an operating mechanism for moving the machining head 13 in the Y-axis direction, and a servo motor that constitutes an operating mechanism for moving the machining head 13 in the Z-axis direction. The head drive unit 14 is an operating mechanism that causes the machining head 13 to perform translational motion in the X-axis, Y-axis, and Z-axis directions, respectively. In Figure 1, the illustration of each servo motor is omitted. Note that the head drive unit 14 is not limited to moving the machining head 13 in three mutually perpendicular axes. A multi-axis drive device such as a robot arm may be used for the head drive unit 14.

[0023] The positional relationship between the material supply nozzle and the processing head 13 is fixed. The material supply nozzle moves in conjunction with the processing head 13. The head drive unit 14 can move the irradiation position of the laser beam L and the supply position of the wire 15 to any position within the stroke range of the processing head 13.

[0024] The control device 3 controls the molding unit 2 according to the processing program input to the control device 3 and the processing conditions specified by the processing program. The processing program describes the processing procedure for moving the molding unit 2. The processing conditions include information necessary for forming the object, such as the beam output, which is the output of the laser beam L from the laser oscillator 11; the movement speed, which is the speed at which the processing point is moved; and the wire supply speed 15.

[0025] The control device 3 comprises a molding control unit 4 and a command output unit 5. The molding control unit 4 generates various commands according to the processing program and processing conditions. The command output unit 5 outputs the various commands generated by the molding control unit 4 to the molding unit 2.

[0026] The molding control unit 4 comprises a beam source control unit 21, a material supply control unit 22, and a head control unit 23. The beam source control unit 21 converts the beam output indicated in the processing conditions into a pulsed beam output and generates a beam output command. The beam source control unit 21 outputs the generated beam output command to the command output unit 5. By converting the beam output indicated in the processing conditions into a pulsed beam output and generating a beam output command, the beam source control unit 21 causes the laser oscillator 11 to output a pulsed laser beam L.

[0027] The material supply control unit 22 adjusts the timing for supplying the wire 15 from the material supply unit 12 based on the timing of the pulsed beam output. The material supply control unit 22 generates a material supply command to supply the wire 15 at the adjusted timing. The material supply control unit 22 outputs the generated material supply command to the command output unit 5.

[0028] The head control unit 23 calculates the path for moving the machining point by analyzing the machining procedure described in the machining program. Based on the calculated path and the movement speed indicated in the machining conditions, the head control unit 23 generates a movement command. The movement command represents an interpolated point group along the path. The interpolated point group is a set of interpolated points that represent the position of the machining point at each unit of time. The head control unit 23 outputs the generated movement command to the command output unit 5.

[0029] The command output unit 5 outputs the beam output command generated by the beam source control unit 21 to the laser oscillator 11. The control device 3 controls the laser oscillator 11 by outputting the beam output command to the laser oscillator 11. The laser oscillator 11 outputs the laser beam L according to the beam output command.

[0030] The command output unit 5 outputs the material supply command generated by the material supply control unit 22 to the material supply unit 12. The control device 3 controls the material supply unit 12 by outputting the material supply command to the material supply unit 12. The material supply unit 12 supplies the wire 15 according to the material supply command.

[0031] The command output unit 5 outputs the movement command generated by the head control unit 23 to the head drive unit 14. The control device 3 controls the head drive unit 14 by outputting the movement command to the head drive unit 14. The head drive unit 14 moves the machining head 13 according to the movement command.

[0032] Next, the details of the control of the laser oscillator 11 by the beam source control unit 21 will be described. The beam output indicated in the processing conditions is, for example, a constant value. That is, the processing conditions indicate that the output of the laser beam L should be maintained at a constant value during the fabrication process.

[0033] The beam source control unit 21 converts a constant beam output value indicated in the processing conditions into a pulsed beam output. The beam source control unit 21 converts the beam output indicated in the processing conditions into a pulsed beam output and generates a beam output command. The laser oscillator 11 outputs a pulsed laser beam L according to the beam output command generated by the beam source control unit 21.

[0034] When the beam source control unit 21 converts the beam output indicated in the processing conditions into a pulsed beam output, it adjusts the amplitude and pulse width of the pulsed beam output so that the amount of heat in the beam per pulse is sufficient to melt the amount of material to be attached to the processing point. In this way, the beam source control unit 21 determines the pulse waveform of the beam output so that the laser beam L melts the wire 15 with each pulse.

[0035] Figure 2 is a first diagram illustrating the determination of pulse waveforms by the beam source control unit 21 of the additive manufacturing apparatus 1 according to Embodiment 1. Figure 3 is a second diagram illustrating the determination of pulse waveforms by the beam source control unit 21 of the additive manufacturing apparatus 1 according to Embodiment 1.

[0036] Figure 2 shows the fabrication process when the tip 31 of the wire 15 that reaches the processing point is melted by a single-pulse laser beam L. Figure 3 shows the fabrication process when the tip 31 of the wire 15 that reaches the processing point is melted by a multi-pulse laser beam L. As an example, Figure 3 shows the case where the tip 31 is melted by a two-pulse laser beam L. Here, it is intended that the molten material 32 will come into contact with the bead 33 formed on the workpiece 17 when the molten material 32 is applied. In Figures 2 and 3, the halftone dots on the tip 31 indicate that the temperature of the tip 31 has reached its melting point.

[0037] As shown in Figure 2, when one pulse of laser beam L is irradiated, the tip 31 irradiated by the laser beam L is heated to the melting point of the wire 15, causing the amount of wire 15 to melt and adhere to the processing point. At this time, the molten material 32 adheres to the position on the workpiece 17 irradiated by one pulse of laser beam L. The molten material 32 adheres to the workpiece 17 while in contact with the bead 33 on the workpiece 17. This makes it possible to adhere the molten material 32 to the intended position at the timing of the irradiation of one pulse of laser beam L.

[0038] On the other hand, in the case shown in Figure 3, the tip 31 is heated to the melting point of the wire 15 by irradiating it twice with a single pulse of laser beam L. As the processing point moves during the two irradiations of the single pulse of laser beam L, the molten material 32 adheres to a position away from the bead 33 on the workpiece 17. In this case, the inability to adhere the molten material 32 to the intended position can lead to problems such as deterioration of the shape accuracy of the fabricated object or failure of the fabrication.

[0039] When the additive manufacturing apparatus 1 irradiates a single pulse of the laser beam L, the wire 15 in an amount to be adhered to the processing point melts, so that the melted material 32 can be adhered to the intended position. As a result, the additive manufacturing apparatus 1 can reduce the occurrence of problems such as deterioration of the shape accuracy of the formed object or failure of the forming.

[0040] The additive manufacturing apparatus 1 converts the beam output indicated in the processing conditions into a pulsed beam output, and outputs a pulsed beam from the laser oscillator 11. The additive manufacturing apparatus 1 can suppress the temperature rise of the workpiece 17 by stopping the irradiation of the laser beam L during the pulse pause time, compared with the case where the irradiation of the laser beam L is continued.

[0041] FIG. 4 is a first diagram for explaining the conversion of the beam output by the beam source control unit 21 of the additive manufacturing apparatus 1 according to the first embodiment. FIG. 4 shows an example of a graph representing the relationship between the amplitude and the pulse width of the pulse waveform. In FIG. 4, the vertical axis represents the amplitude. The horizontal axis represents the pulse width. The product of the amplitude and the pulse width corresponds to the amount of heat per pulse of the laser beam L.

[0042] In FIG. 4, the curve N1 represents the relationship between the amplitude and the pulse width when the amount of heat per pulse of the laser beam L is q1. The curve N2 represents the relationship between the amplitude and the pulse width when the amount of heat per pulse of the laser beam L is q2. The curve N3 represents the relationship between the amplitude and the pulse width when the amount of heat per pulse of the laser beam L is q3. q1 < q2 < q3 holds. When the amount of heat per pulse of the laser beam L is obtained, the amplitude and the pulse width can be determined from the relationship between the amplitude and the pulse width.

[0043] Figure 5 is a second diagram illustrating the conversion of beam output by the beam source control unit 21 of the additive manufacturing apparatus 1 according to Embodiment 1. The beam source control unit 21 calculates the amount of heat required to melt the amount of material to be attached to the processing point, based on the material properties and the material supply method. The material properties include, for example, the melting point, the beam absorptivity, and the heat capacity. The supply method includes, for example, the diameter of the wire 15 and the volume of wire 15 melted per unit area. The unit area mentioned above refers to the unit area of ​​the irradiation area of ​​the laser beam L. The volume of wire 15 melted per unit area can be determined, for example, by a calculation that incorporates the wire supply angle. The wire supply angle is the angle between the central axis of the beam nozzle and the direction of travel of the wire 15 when the wire 15 is supplied to the workpiece 17.

[0044] Here, let's assume that the amount of heat required to melt the amount of material to be attached to the processing point is calculated to be q. In Figure 5, curve N represents the relationship between amplitude and pulse width when the amount of heat per pulse of the laser beam L is q. In Figure 5, the hatched region A represents the range of amplitude and pulse width when the amount of heat per pulse of the laser beam L is q or greater. The beam source control unit 21 determines the combination of amplitude and pulse width that is included in region A. In this way, the beam source control unit 21 calculates the amplitude and pulse width of the pulsed beam output.

[0045] Figure 6 is a third diagram illustrating the conversion of beam output by the beam source control unit 21 of the additive manufacturing apparatus 1 according to Embodiment 1. The upper part of Figure 6 shows a graph representing the relationship between beam output and time, as indicated by the processing conditions. In the upper part of Figure 6, the vertical axis represents beam output, and the horizontal axis represents time. The lower part of Figure 6 shows an example of the pulse waveform of the beam output calculated by the beam source control unit 21. In the lower part of Figure 6, the vertical axis represents beam output, and the horizontal axis represents time.

[0046] Here, let I0 be the beam output value indicated in the processing conditions. The relationship between beam output and time, as shown in the upper part of Figure 6, is represented by a horizontal straight line graph.

[0047] As described above, the amplitude and pulse width of the pulse waveform shown in the lower part of Figure 6 are determined by the beam source control unit 21. Furthermore, the beam source control unit 21 adjusts the pause time of the pulsed beam output so that the average amount of heat supplied by the pulsed beam output is the same as the amount of heat supplied by a constant beam output as indicated in the processing conditions. The beam source control unit 21 calculates the pulse pause time such that there is no change in the average amount of heat supplied by the laser beam L before and after the conversion of the beam output. As a result, the additive manufacturing apparatus 1 can execute the fabrication process by supplying the same amount of heat as when the laser beam L with the beam output indicated in the processing conditions is used.

[0048] Next, the details of the control of the material supply unit 12 by the material supply control unit 22 will be described. The wire supply speed of the wire 15, as indicated in the processing conditions, is, for example, a constant value. That is, the processing conditions indicate that the wire supply speed of the wire 15 should be maintained at a constant value during the molding process. The material supply control unit 22 adjusts the wire supply speed of the wire 15 so that the supply of the wire 15 and the stopping of the wire supply of the wire 15 are repeated alternately. The material supply control unit 22 adjusts the timing of supplying the wire 15 from the material supply unit 12 based on the pulsed beam output.

[0049] Figure 7 is a first diagram illustrating the adjustment of the wire 15 supply speed by the material supply control unit 22 of the additive manufacturing apparatus 1 according to Embodiment 1. The upper part of Figure 7 shows the same graph as shown in the lower part of Figure 6. The lower part of Figure 7 shows a graph representing the relationship between supply speed and time after adjustment by the material supply control unit 22. In the lower part of Figure 7, the vertical axis represents the wire 15 supply speed, and the horizontal axis represents time. As shown in the lower part of Figure 7, the wire 15 supply speed is represented by a pulse waveform indicating the timing of wire 15 supply.

[0050] When irradiating with the laser beam L, a wire 15 must be supplied to the processing point. Therefore, the material supply control unit 22 adjusts the timing of supplying the wire 15 from the material supply unit 12 so that the wire 15 is supplied immediately before the output of the laser beam L. As shown in the upper and lower panels of Figure 7, the pulse waveform indicating the supply speed of the wire 15 is synchronized with the timing when the output of the laser beam L is paused, immediately before the pulse waveform of the laser beam L.

[0051] The material supply control unit 22 calculates a supply rate such that the amount of material supplied to the workpiece 17 is the same as the amount supplied at the supply rate indicated in the processing conditions. The supply rate calculated here corresponds to the amplitude of the pulse waveform indicating the supply rate of the wire 15. In other words, the material supply control unit 22 adjusts the supply rate so that there is no change in the average supply rate of the wire 15 before and after the adjustment of the timing of wire supply. As a result, the additive manufacturing apparatus 1 can supply the same amount of material as when the material is supplied at the supply rate indicated in the processing conditions and execute the molding process.

[0052] If a pulsed laser beam L is output while the wire 15 is supplied at a constant speed, the wire 15 may become stuck to the workpiece 17 if the supply of the wire 15 continues during the pauses in the laser beam L. The additive manufacturing apparatus 1 can prevent the wire 15 from becoming stuck to the workpiece 17 by adjusting the timing of the wire 15 supply in accordance with the pulsed beam output. As a result, the additive manufacturing apparatus 1 can execute the molding process while avoiding problems such as the cancellation of processing due to the wire 15 becoming stuck.

[0053] The material supply control unit 22 may also cause the material supply unit 12 to perform a pull-back operation. Here, the pull-back operation refers to the operation of returning the wire 15 to the material supply source after it has been fed out from the material supply source.

[0054] Figure 8 is a second diagram illustrating the adjustment of the wire 15 supply speed by the material supply control unit 22 of the additive manufacturing apparatus 1 according to Embodiment 1. The upper part of Figure 8 shows the same graph as shown in the lower part of Figure 6. The lower part of Figure 8 shows a graph representing the relationship between the supply speed and time when the material supply unit 12 is made to perform a pull-back operation. In the lower part of Figure 8, the vertical axis represents the wire 15 supply speed, and the horizontal axis represents time.

[0055] The graph shown in the lower part of Figure 8 differs from the graph shown in the lower part of Figure 7 in that it includes a pulse waveform representing the pull-back operation. The pulse waveform representing the pull-back operation is a pulse waveform that represents the change in the supply speed from zero to the negative direction. In addition, because the wire 15 is returned to the material supply source by the pull-back operation, the supply speed at which the wire 15 is supplied to the workpiece 17 is higher than when the pull-back operation is not performed.

[0056] The pull-back motion causes the wire 15 to be withdrawn from the processing point. By withdrawing the wire 15 from the processing point, the additive manufacturing apparatus 1 can prevent the wire 15 from becoming stuck to the workpiece 17.

[0057] Next, the procedure of processing performed by the control device 3 will be described. Figure 9 is a flowchart showing an example of the procedure of processing performed by the control device 3 of the additive manufacturing apparatus 1 according to Embodiment 1.

[0058] In step S1, the beam source control unit 21 calculates the amplitude and pulse width of the pulsed beam output. The beam source control unit 21 calculates the amplitude and pulse width such that the amount of heat in the beam per pulse is sufficient to melt the amount of material to be attached to the processing point.

[0059] In step S2, the beam source control unit 21 converts the beam output indicated in the processing conditions into a pulsed beam output. The beam source control unit 21 calculates the pulse pause time so that the average of the pulsed beam output having the amplitude and pulse width calculated in step S1 is the same as the beam output indicated in the processing conditions. Once the amplitude, pulse width, and pause time are determined, the pulse waveform of the beam output is determined. The beam source control unit 21 generates a beam output command to output the pulsed laser beam L.

[0060] In step S3, the material supply control unit 22 adjusts the timing of material supply based on the timing of the pulsed beam output obtained by the conversion in step S2. The material supply control unit 22 adjusts the timing of supplying the wire 15 from the material supply unit 12 so that the wire 15 is supplied immediately before the pulse of the beam output. The material supply control unit 22 also adjusts the material supply speed so that the amount of material supplied to the workpiece 17 is the same as the amount supplied at the supply speed indicated in the processing conditions. The material supply control unit 22 generates a material supply command to supply the wire 15 at the adjusted supply speed.

[0061] The beam source control unit 21 outputs the generated beam output command to the command output unit 5. The material supply control unit 22 outputs the generated material supply command to the command output unit 5. The head control unit 23 generates a movement command by analyzing the processing program. The head control unit 23 outputs the generated movement command to the command output unit 5.

[0062] In step S4, the command output unit 5 outputs a beam output command, a material supply command, and a movement command to the molding unit 2. With this, the control device 3 completes the processing according to the procedure shown in Figure 9.

[0063] According to Embodiment 1, the additive manufacturing apparatus 1 includes a material supply unit 12 and a beam source, and comprises a molding unit 2 that forms a molded object by adhering a material melted by a beam to a workpiece 17, and a beam source control unit 21 that converts the beam output indicated in the processing conditions into a pulsed beam output to generate a beam output command, thereby causing a pulsed beam to be output from the beam source. By outputting a pulsed beam from the beam source, the additive manufacturing apparatus 1 can suppress the temperature rise of the workpiece 17 compared to when the beam is continuously irradiated onto the workpiece 17. As a result, the additive manufacturing apparatus 1 has the effect of reducing the thermal effects in the molding process.

[0064] The beam source control unit 21 may adjust the amplitude and pulse width of the pulsed beam output so that the amount of heat from the beam per pulse is sufficient to melt the amount of material to be attached to the processing point of the workpiece 17. The additive manufacturing apparatus 1 can attach the molten material to the position on the workpiece 17 irradiated by one pulse of the beam. This allows the additive manufacturing apparatus 1 to attach the material to the intended location. The additive manufacturing apparatus 1 can reduce the occurrence of defects such as deterioration of the shape accuracy of the fabricated object or failure of the fabrication.

[0065] The additive manufacturing apparatus 1 may also include a material supply control unit 22 that adjusts the timing of supplying material from the material supply unit 12 based on the pulsed beam output. This allows the additive manufacturing apparatus 1 to prevent the wire 15 from sticking to the workpiece 17 and reduce the occurrence of defects in the molding process.

[0066] The beam source control unit 21 may adjust the pause time of the pulsed beam output so that the average amount of heat supplied by the pulsed beam output is the same as the amount of heat supplied by the beam output indicated in the processing conditions. This allows the additive manufacturing apparatus 1 to execute the fabrication process by supplying the same amount of heat as when the beam output indicated in the processing conditions is used.

[0067] Embodiment 2. In Embodiment 1, the amount of heat from the beam per pulse was set to be sufficient to melt the amount of material to be attached to the processing point. In Embodiment 2, an example is described in which the amount of heat from the beam per pulse is set to the minimum amount of heat sufficient to melt the amount of material to be attached to the processing point.

[0068] The additive manufacturing apparatus 1 according to Embodiment 2 has the same configuration as the additive manufacturing apparatus 1 according to Embodiment 1. In Embodiment 2, the same reference numerals are used for the same components as in Embodiment 1, and the description will mainly focus on processes that differ from those in Embodiment 1.

[0069] Figure 10 is a first diagram illustrating the relationship between the beam output and the formed object in the additive manufacturing apparatus 1 according to Embodiment 2. Figure 11 is a second diagram illustrating the relationship between the beam output and the formed object in the additive manufacturing apparatus 1 according to Embodiment 2.

[0070] The upper part of Figure 10 shows a first example of the pulse waveform of the beam output. In the upper part of Figure 10, the vertical axis represents the beam output, and the horizontal axis represents time. The lower part of Figure 10 shows the bead formed by the laser beam L with the pulse waveform shown in the upper part of Figure 10. Each of the circles shown in the lower part of Figure 10 represents the shape of the bead in the XY plane. I0 represents the beam output value indicated in the processing conditions.

[0071] The upper panel of Figure 11 shows a second example of the pulse waveform of the beam output. In the upper panel of Figure 11, the vertical axis represents the beam output, and the horizontal axis represents time. The lower panel of Figure 11 shows the bead formed by the laser beam L with the pulse waveform shown in the upper panel of Figure 11. Each of the circles shown in the lower panel of Figure 11 represents the shape of the bead in the XY plane.

[0072] The pulse pause time in the first example shown in the upper part of Figure 10 is shorter than the pulse pause time in the second example shown in the upper part of Figure 11. The multiple beads shown in the lower part of Figure 10 are arranged in a straight line without any gaps. The multiple beads shown in the lower part of Figure 11 are arranged in a straight line. In the lower part of Figure 11, there are gaps between the beads.

[0073] If the output of the laser beam L is maintained at a constant value and the wire 15 is supplied at a constant speed, a linear bead is formed. When a pulsed laser beam L is output, as in Embodiment 2, a dot-like bead is formed. When a pulsed laser beam L is output, the shorter the pause time between pulses, the greater the number of irradiation positions of the laser beam L per unit length of the path. The greater the number of irradiation positions of the laser beam L per unit length of the path, the closer the shape of the multiple beads arranged in a straight line will be to the shape of a linear bead. The closer the shape of the multiple beads is to the shape of a linear bead, the higher the shape accuracy of the fabricated object.

[0074] In the lower section of Figure 10, the multiple beads are arranged without gaps, whereas in the lower section of Figure 11, the multiple beads are arranged with spaces between them. Therefore, the first example shown in Figure 10 has higher shape accuracy than the second example shown in Figure 11. In the second example shown in Figure 11, the spacing between the multiple beads results in poor shape accuracy.

[0075] As described above, by making the pulse width as short as possible, the number of irradiation positions of the laser beam L per unit length of the path can be made as large as possible. Also, as explained in Embodiment 1, the additive manufacturing apparatus 1 needs to supply enough heat with one pulse of the laser beam L to melt the amount of material to be attached to the processing point.

[0076] Therefore, in Embodiment 2, the beam source control unit 21 adjusts the amplitude and pulse width of the pulsed beam output so that the amount of heat in the beam per pulse is the minimum amount of heat that can melt the amount of material to be attached to the processing point of the workpiece 17. The beam source control unit 21 also determines the maximum output of the beam source as the amplitude of the pulsed beam output. As a result, the beam source control unit 21 can supply enough heat in one pulse of the laser beam L to melt the amount of material to be attached to the processing point while minimizing the pulse width of the pulsed beam output. By minimizing the pulse width, the number of irradiation positions of the laser beam L per unit length of the path is maximized, so the additive manufacturing apparatus 1 can achieve high shape accuracy of the fabricated object.

[0077] Figure 12 is a diagram illustrating the determination of the pulse waveform by the beam source control unit 21 of the additive manufacturing apparatus 1 according to Embodiment 2. Figure 12 shows a graph similar to that in Figure 5. Similar to Figure 5, curve N represents the relationship between amplitude and pulse width when the amount of heat per pulse of the laser beam L is q. q represents the amount of heat required to melt the amount of material to be deposited at the processing point. max This represents the maximum output of the laser oscillator 11.

[0078] The star mark shown in Figure 12 indicates an amplitude of I max This represents a point on curve N when the following condition is met. The pulse width indicated by such a point is the minimum pulse width when the heat per pulse of the laser beam L is q.

[0079] The beam source control unit 21 controls the maximum output of the beam source, I max This is determined to be the amplitude of the pulsed beam output. The beam source control unit 21 also determines that the amplitude is I max The pulse width indicated by a point on curve N when this is the case is determined as the amplitude of the pulsed beam output. In this way, the beam source control unit 21 adjusts the amplitude and pulse width of the pulsed beam output so that the amount of heat in the beam per pulse is the minimum amount of heat that can melt the amount of material to be attached to the processing point of the workpiece 17.

[0080] Figure 13 is a diagram illustrating the conversion of beam output by the beam source control unit 21 of the additive manufacturing apparatus 1 according to Embodiment 2. The upper part of Figure 13 shows a graph representing the relationship between beam output and time, as indicated by the processing conditions. In the upper part of Figure 13, the vertical axis represents beam output, and the horizontal axis represents time. The lower part of Figure 13 shows an example of the pulse waveform of the beam output calculated by the beam source control unit 21. In the lower part of Figure 13, the vertical axis represents beam output, and the horizontal axis represents time.

[0081] Regarding the beam output specified in the processing conditions, the relationship between beam output and time is represented by a horizontal linear graph, as shown in the upper part of Figure 13. The amplitude and pulse width of the pulse waveform shown in the lower part of Figure 13 are determined by the beam source control unit 21, as described above.

[0082] According to Embodiment 2, the beam source control unit 21 adjusts the amplitude and pulse width of the pulsed beam output so that the amount of heat from the beam per pulse is the minimum amount of heat required to melt the amount of material to be attached to the processing point of the workpiece 17. The additive manufacturing apparatus 1 can melt material with each pulse because the amount of heat from the beam per pulse is the minimum amount of heat required to melt the amount of material to be attached to the processing point of the workpiece 17. By melting material with each pulse, the additive manufacturing apparatus 1 can attach material to the intended location. Furthermore, the additive manufacturing apparatus 1 can shorten the pulse width of the beam because the amount of heat from the beam per pulse is the minimum amount of heat required to melt the amount of material to be attached to the processing point of the workpiece 17. By shortening the pulse width of the beam, the additive manufacturing apparatus 1 can increase the number of beam irradiation positions per unit length of the path. As a result, the additive manufacturing apparatus 1 can improve the shape accuracy of the fabricated object.

[0083] The beam source control unit 21 may determine the maximum output of the beam source as the amplitude of the pulsed beam output. By determining the maximum output of the beam source as the amplitude, the additive manufacturing apparatus 1 can melt the material with each pulse using a beam with the smallest pulse width. By minimizing the pulse width of the beam, the additive manufacturing apparatus 1 can maximize the number of beam irradiation positions per unit length of the path. As a result, the additive manufacturing apparatus 1 can improve the shape accuracy of the fabricated object.

[0084] In the above, the maximum output of the beam source was determined by the amplitude of the beam output. However, the amplitude of the beam output is not limited to the maximum output and may be any output lower than the maximum output. In this case as well, the beam source control unit 21 can adjust the pulse width appropriately according to the amplitude to set the amount of heat in the beam per pulse to the minimum amount of heat that can melt the amount of material to be attached to the processing point.

[0085] Embodiment 3. Embodiment 3 describes an example in which a pulsed beam is irradiated in a deceleration unit that reduces the speed at which the machining head 13 moves to a command value according to the machining conditions. In Embodiment 3, the same reference numerals are used for components that are the same as in Embodiment 1 or 2, and the description will mainly focus on configurations that differ from Embodiment 1 or 2.

[0086] Figure 14 shows an example of the configuration of an additive manufacturing apparatus 1A according to Embodiment 3. The additive manufacturing apparatus 1A comprises a molding unit 2 for forming a molded object and a control device 3A. The control device 3A comprises a molding control unit 4, a command output unit 5, and an analysis unit 6.

[0087] The analysis unit 6 detects deceleration sections included in the path by analyzing the machining program. A deceleration section is a part of the path where the speed at which the machining head 13 moves is reduced to a speed indicated in the machining conditions. In Embodiment 3, the deceleration section includes a corner where the direction of the path changes, the starting point of the path, and the ending point of the path. When the analysis unit 6 detects a deceleration section, it outputs information indicating the part of the path corresponding to the deceleration section to the molding control unit 4.

[0088] The head control unit 23 calculates the path for moving the machining point by analyzing the machining program. For the portion of the path excluding the deceleration section, the head control unit 23 generates a movement command based on the calculated path and the movement speed indicated in the machining conditions. The head control unit 23 calculates the movement speed of the machining head 13 in the deceleration section. At this time, the head control unit 23 calculates a movement speed lower than the movement speed indicated in the machining conditions. For the portion of the path excluding the deceleration section, the head control unit 23 generates a movement command based on the calculated path and the calculated movement speed.

[0089] The beam source control unit 21 generates beam output commands based on the beam output specified in the processing conditions for the portion of the path other than the deceleration section. For the portion of the path other than the deceleration section, the beam source control unit 21 outputs a laser beam L with the beam output specified in the processing conditions from the laser oscillator 11.

[0090] The beam source control unit 21 generates a beam output command for the deceleration section of the path by converting the beam output indicated in the processing conditions into a pulsed beam output. For the deceleration section of the path, the beam source control unit 21 outputs a pulsed laser beam L from the laser oscillator 11.

[0091] Figure 15 is a diagram illustrating the deceleration section included in the path for moving the machining head 13 in Embodiment 3. Figure 15 shows an example of a portion of the path that includes a corner section, which is a deceleration section. In Figure 15, the portion between P1 and P3 is a corner section. The direction of the path changes by nearly 90 degrees at P2. P2 is the apex of the corner section.

[0092] The analysis unit 6 determines P1, which is a position that moves in the direction opposite to the traveling direction from P2 among the paths, as the starting point of the corner part. As the distance from the vertex of the corner part to the starting point of the corner part, any distance can be set. The analysis unit 6 determines P3, which is a position that moves in the traveling direction from P2 among the paths, as the end point of the corner part. As the distance from the vertex of the corner part to the end point of the corner part, any distance can be set. The analysis unit 6 detects the portion between P1 and P3 among the paths as the deceleration part.

[0093] FIG. 16 is a diagram showing an example of the moving speed calculated by the head control unit 23 of the additive manufacturing apparatus 1A according to Embodiment 3. FIG. 16 shows a graph representing the relationship between the moving speed of the processing head 13 and time. In FIG. 16, the vertical axis represents the moving speed of the processing head 13. The horizontal axis represents time. FIG. 16 shows an example of a graph of the moving speed calculated for the path shown in FIG. 15. V0 represents the moving speed indicated in the processing conditions. t1 represents the time when the processing point passes through P1. t2 represents the time when the processing point passes through P2. t3 represents the time when the processing point passes through P3.

[0094] As shown in FIG. 16, at a time before t1, the moving speed is maintained constant at V0. The moving speed decreases from t1 to t2 a until, and reaches the minimum value in the corner part at t2 a . The moving speed is maintained constant at the minimum value from t2 a to t2 b . The moving speed increases from t2 b to t3 and reaches V0 at t3. At a time after t3, the moving speed is maintained constant at V0.

[0095] Figure 17 is the first diagram illustrating the conversion of beam output by the beam source control unit 21 of the additive manufacturing apparatus 1A according to Embodiment 3. Figure 17 shows a graph representing the relationship between beam output and time when the beam output is changed to follow the change in moving speed shown in Figure 16. In Figure 17, the vertical axis represents beam output, and the horizontal axis represents time.

[0096] The pattern of change in beam output in the graph shown in Figure 17 is the same as in the graph shown in Figure 16. For example, if the movement speed of the processing head 13 is reduced while the beam output is kept constant, the heat input may become excessive. Therefore, by reducing the beam output in accordance with the decrease in movement speed and increasing the beam output in accordance with the increase in movement speed, excessive heat input in the manufacturing process is prevented.

[0097] In Figure 17, I L This represents the lower limit of the beam power required to execute a normal fabrication process. If the beam power falls below this limit, the material will not melt, potentially leading to defects such as poor shape accuracy or complete failure of the fabricated object. As shown in Figure 17, if the beam power is to be changed to follow changes in movement speed, the minimum beam power must be lower than the lower limit, making it difficult to avoid defects.

[0098] In Embodiment 3, the additive manufacturing apparatus 1A outputs a pulsed laser beam L from the laser oscillator 11 to the reduction gear. This prevents the additive manufacturing apparatus 1A from applying excessive heat and allows the material to melt at the processing point.

[0099] Figure 18 is a second diagram illustrating the conversion of beam output by the beam source control unit 21 of the additive manufacturing apparatus 1A according to Embodiment 3. The upper part of Figure 18 shows the same graph as in Figure 17. The lower part of Figure 18 shows a graph representing the relationship between beam output and time, for the beam output calculated by the beam source control unit 21. In the lower part of Figure 18, the vertical axis represents beam output, and the horizontal axis represents time.

[0100] The beam source control unit 21 converts the beam output at the corner from the beam output shown in the upper part of Figure 18 to a pulsed beam output. The beam source control unit 21 adjusts the amplitude and pulse width of the pulsed beam output so that the amount of heat in the beam per pulse is sufficient to melt the amount of material to be attached to the processing point. As shown in the graph in the lower part of Figure 18, the beam source control unit 21 adjusts the maximum output of the laser oscillator 11 to I max This may be determined as the amplitude of the pulsed beam output. In this case, the beam source control unit 21 can minimize the pulse width of the pulsed beam output while supplying enough heat with one pulse of the laser beam L to melt the amount of material to be attached to the processing point.

[0101] Furthermore, the beam source control unit 21 adjusts the pause time of the pulsed beam output so that the average amount of heat supplied by the pulsed beam output is the same as the amount of heat supplied by the beam output indicated in the processing conditions. The beam source control unit 21 calculates the pulse pause time such that there is no change in the average amount of heat supplied by the laser beam L before and after the conversion of the beam output. The arrow between the upper and lower parts of Figure 18 indicates that the amount of heat supplied by the beam output before conversion is replaced by each pulse of the beam output after conversion.

[0102] By adjusting the pulse pause time as described above, the additive manufacturing apparatus 1A can input the same amount of heat as when a laser beam L with the beam output indicated in the processing conditions is used, and execute the fabrication process.

[0103] Next, the operation procedure of the additive manufacturing apparatus 1A will be described. Figure 19 is a flowchart showing an example of the operation procedure of the additive manufacturing apparatus 1A according to Embodiment 3.

[0104] In step S11, the molding unit 2 starts molding. The analysis unit 6 determines whether there is a deceleration section in the path by looking up the machining program. Looking up refers to analyzing the machining program for processes that will be executed after the currently executing process.

[0105] In step S12, the analysis unit 6 determines whether or not a deceleration unit has been detected. If no deceleration unit has been detected (step S12, No), in step S13, the additive manufacturing apparatus 1A performs molding according to the processing conditions. The additive manufacturing apparatus 1A returns to step S12.

[0106] If a reduction gear is detected (step S12, Yes), in step S14, the head control unit 23 calculates the reduction amount in the reduction gear. Based on the reduction amount, the head control unit 23 calculates the movement speed of the machining head 13.

[0107] In step S15, the molding control unit 4 calculates the beam output and material supply rate based on the deceleration amount calculated in step S14. The beam source control unit 21 adjusts the beam output in the deceleration section to a lower value than the beam output in the parts other than the deceleration section in order to prevent excessive heat from being introduced into the deceleration section. The material supply control unit 22 calculates the material supply rate by determining the amount of material that can be melted by the laser beam L with the beam output calculated by the beam source control unit 21.

[0108] In step S16, the beam source control unit 21 calculates the amplitude and pulse width of the pulsed beam output. The beam source control unit 21 determines the amplitude and pulse width such that the amount of heat in the beam per pulse is sufficient to melt the amount of material to be attached to the processing point.

[0109] In step S17, the molding control unit 4 converts the beam output calculated in step S15 into a pulsed beam output and adjusts the timing for supplying material. The beam source control unit 21 adjusts the pause time of the pulsed beam output so that the average amount of heat supplied by the pulsed beam output with the amplitude and pulse width calculated in step S16 is the same as the amount of heat supplied by the beam output calculated in step S15. The beam source control unit 21 generates a beam output command to output the pulsed laser beam L.

[0110] The material supply control unit 22 adjusts the timing of material supply based on the timing of the pulsed beam output obtained by the conversion in the beam source control unit 21. The material supply control unit 22 also adjusts the material supply rate so that the amount of material supplied to the workpiece 17 is the same as the amount supplied at the supply rate calculated in step S15. The material supply control unit 22 generates a material supply command to supply the wire 15 at the adjusted supply rate.

[0111] The command output unit 5 outputs a beam output command, a material supply command, and a movement command to the molding unit 2. In step S18, the molding unit 2 performs molding in the deceleration unit. In step S19, the analysis unit 6 determines whether or not to terminate the molding in the deceleration unit. If the molding in the deceleration unit is not terminated (step S19, No), the additive manufacturing apparatus 1A returns to step S18. If the molding in the deceleration unit is terminated (step S19, Yes), in step S20, the molding unit 2 performs molding in the parts other than the deceleration unit according to the processing conditions. Thus, the additive manufacturing apparatus 1A completes its operation according to the procedure shown in Figure 19.

[0112] According to Embodiment 3, the beam source control unit 21 converts the beam output indicated in the processing conditions into a pulsed beam output in the reduction unit, which reduces the speed at which the processing head 13 moves to a speed lower than that indicated in the processing conditions. As a result, the additive manufacturing apparatus 1A can reduce the thermal influence in the molding process of the reduction unit.

[0113] Embodiment 4. Embodiment 4 describes an example of adjusting the pulse timing in the deceleration unit. The additive manufacturing apparatus 1A according to Embodiment 4 has the same configuration as the additive manufacturing apparatus 1A according to Embodiment 3. In Embodiment 4, the same reference numerals are used for the same components as in Embodiments 1 to 3, and the description mainly focuses on processes that differ from those in Embodiments 1 to 3.

[0114] If the deceleration section includes a corner section, the beam source control unit 21 synchronizes one pulse of the beam to the timing when the machining head 13 passes through the point in the corner section where the speed of the machining head 13 is at its lowest value. Alternatively, if the deceleration section includes a corner section, the beam source control unit 21 synchronizes one pulse of the beam to the timing when the machining head 13 passes through the midpoint of the range in the corner section where the speed of the machining head 13 is at its lowest value.

[0115] If the deceleration section includes the start and end points of the path, the beam source control unit 21 synchronizes one pulse of the beam to the timing when the machining head 13 starts moving from the start point and the timing when the machining head 13 reaches the end point.

[0116] Figure 20 shows a first example of the travel speed calculated by the head control unit 23 of the additive manufacturing apparatus 1A according to Embodiment 4. Figure 21 shows a second example of the travel speed calculated by the head control unit 23 of the additive manufacturing apparatus 1A according to Embodiment 4. Figure 22 shows a third example of the travel speed calculated by the head control unit 23 of the additive manufacturing apparatus 1A according to Embodiment 4. Figures 20 to 22 show graphs representing the relationship between the travel speed of the processing head 13 and time. In Figures 20 to 22, the vertical axis represents the travel speed of the processing head 13. The horizontal axis represents time.

[0117] The first example shown in Figure 20 is an example graph of the travel speed along a path including a corner. V0 represents the travel speed indicated in the processing conditions. In Figure 20, the travel speed decreases from t11 to t12, reaching its lowest value at t12. t12 is the timing when the processing point passes the apex of the corner. The travel speed also increases from t12 to t13. The beam source control unit 21 aligns one pulse of the beam to t12, when the travel speed is at its lowest value.

[0118] The second example shown in Figure 21 is an example of a graph of the moving speed in a path that includes a corner. In Figure 21, the moving speed decreases from t21 to t22 and reaches its lowest value from t22 to t24. t23 is the midpoint of the range from t22 to t24 where the speed of the machining head 13 is at its lowest value. t23 is the timing when the machining point passes through the apex of the corner. The moving speed also increases from t24 to t25. The beam source control unit 21 aligns one pulse of the beam to t23, which is the midpoint of the range where the moving speed is at its lowest value.

[0119] Thus, when the deceleration section included in the path is a corner section, the beam source control unit 21 aligns one pulse of the beam to the point where the moving speed is at its lowest value in the corner section, or to the midpoint of the range where the moving speed is at its lowest value in the corner section. The additive manufacturing apparatus 1A then deposits the molten material at the point where the moving speed is at its lowest value, or to the midpoint where the moving speed is at its lowest value. This allows the additive manufacturing apparatus 1A to improve the shape accuracy of the formed object.

[0120] The third example shown in Figure 22 is an example graph of the movement speed along a path that includes the start and end points of the path. t31 is the timing when the machining head 13 starts moving from the start point. t32 is the timing when the machining head 13 reaches the end point. In Figure 22, the movement speed is zero at t31. The movement speed increases from t31 until it reaches V0. After that, the movement speed is maintained constant at V0. The movement speed decreases from the timing before the machining head 13 reaches the end point until t32. The movement speed becomes zero at t32. The beam source control unit 21 aligns one pulse of the beam to each of t31 and t32.

[0121] Thus, when the deceleration section included in the path is at the start and end points of the path, the beam source control unit 21 synchronizes one pulse of the beam to the timing when the processing head 13 starts moving from the start point and the timing when the processing head 13 reaches the end point. The additive manufacturing apparatus 1A then deposits the molten material at both the start and end points. This allows the additive manufacturing apparatus 1A to improve the shape accuracy of the fabricated object.

[0122] In Embodiment 4, the beam source control unit 21 synchronizes one pulse of the beam to the timing when the processing head 13 passes through the point in the corner where the processing head 13's speed is at its lowest value in the corner, or when the processing head 13 passes through the midpoint of the range in the corner where the processing head 13's speed is at its lowest value in the corner. This allows the additive manufacturing apparatus 1A to improve the shape accuracy of the fabricated object.

[0123] The beam source control unit 21 synchronizes one pulse of the beam to the timing when the processing head 13 starts moving from the starting point and the timing when the processing head 13 reaches the end point. This allows the additive manufacturing apparatus 1A to improve the shape accuracy of the fabricated object.

[0124] Next, the hardware configuration for realizing the control devices 3 and 3A according to Embodiments 1 to 4 will be described. The control devices 3 and 3A are realized by processing circuits. The processing circuit is, for example, a circuit in which a processor executes software.

[0125] When the processing circuit is implemented by software, the processing circuit is, for example, the control circuit 40 shown in Figure 23. Figure 23 is a diagram showing an example configuration of the control circuit 40 according to Embodiments 1 to 4. The control circuit 40 comprises an input unit 41, a processor 42, a memory 43, and an output unit 44. The input unit 41 is an interface circuit that receives data input from outside the control circuit 40 and provides it to the processor 42. The output unit 44 is an interface circuit that sends data from the processor 42 or the memory 43 to the outside of the control circuit 40. The output function of the command output unit 5 is realized by using the output unit 44.

[0126] The molding control unit 4 is implemented by software, firmware, or a combination of software and firmware. The software or firmware is written as a program and stored in memory 43. The control circuit 40 implements the functions of the beam source control unit 21, the material supply control unit 22, and the head control unit 23 by having the processor 42 read and execute the program stored in memory 43. The control circuit 40 includes memory 43 for storing the program that will result in the processing of the control devices 3 and 3A being executed. This program can also be said to cause the computer system to execute the procedures and methods of processing of the control devices 3 and 3A. Memory 43 is also used as temporary memory when the processor 42 is executing various processes.

[0127] The molding control unit 4 is realized using a processor 42 and memory 43. The processor 42 is a CPU (Central Processing Unit). The processor 42 may also be a central processing unit, processing unit, arithmetic unit, microprocessor, microcomputer, or DSP (Digital Signal Processor). The memory 43 may be, for example, a non-volatile or volatile semiconductor memory such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), EEPROM (Registered Trademark) (Electrically Erasable Programmable Read Only Memory), magnetic disk, flexible disk, optical disk, compact disk, minidisc, or DVD (Digital Versatile Disc).

[0128] The programs according to Embodiments 1 to 4 may be provided on a recording medium such as a CD (Compact Disc)-ROM or DVD-ROM. The programs according to Embodiments 1 to 4 may be provided by being stored on a computer connected to a network such as the Internet and downloaded via the Internet or other network. The programs according to Embodiments 1 to 4 may be provided or distributed via a network such as the Internet.

[0129] The functions of control devices 3 and 3A may be implemented by dedicated hardware circuits. These dedicated hardware circuits include processing circuits. The processing circuits may be single circuits, composite circuits, programmed processors, parallel programmed processors, ASICs (Application Specific Integrated Circuits), FPGAs (Field Programmable Gate Arrays), or combinations thereof. The functions of control devices 3 and 3A may be implemented separately by processing circuits, or they may be implemented collectively by a single processing circuit. Furthermore, control devices 3 and 3A may be implemented by combining the control circuit 40 and hardware circuits.

[0130] The configurations shown in each of the embodiments described above are examples of the content of this disclosure. The configurations of each embodiment can be combined with other known technologies. The configurations of each embodiment may be combined with each other as appropriate. It is possible to omit or modify parts of the configurations of each embodiment without departing from the gist of this disclosure. [Explanation of symbols]

[0131] 1,1A Additive manufacturing equipment, 2 Molding unit, 3,3A Control device, 4 Molding control unit, 5 Command output unit, 6 Analysis unit, 11 Laser oscillator, 12 Material supply unit, 13 Processing head, 14 Head drive unit, 15 Wire, 16 Fiber cable, 17 Workpiece, 21 Beam source control unit, 22 Material supply control unit, 23 Head control unit, 31 Tip unit, 32 Material, 33 Bead, 40 Control circuit, 41 Input unit, 42 Processor, 43 Memory, 44 Output unit, L Laser beam.

Claims

1. A molding unit having a material supply unit that supplies material toward the processing point of a workpiece and a beam source that outputs a beam, and forming an object by adhering the material melted by the beam to the workpiece, A beam source control unit that generates a beam output command by converting the beam output included in the processing conditions into a pulsed beam output, thereby causing the pulsed beam to be output from the beam source, Equipped with, The beam source control unit adjusts the amplitude and pulse width of the pulsed beam output so that the amount of heat in the beam per pulse is sufficient to melt the amount of material to be attached to the processing point. An additive manufacturing apparatus characterized by the following features.

2. A material supply control unit adjusts the timing of supplying the material from the material supply unit based on the timing of the pulsed beam output. Equipped with The additive manufacturing apparatus according to feature 1.

3. The beam source control unit adjusts the pause time of the pulsed beam output so that the average amount of heat supplied by the pulsed beam output is the same as the amount of heat supplied by the beam output included in the processing conditions. The additive manufacturing apparatus according to claim 1 or 2.

4. The beam source control unit adjusts the amplitude and pulse width of the pulsed beam output so that the amount of heat in the beam per pulse is the minimum amount of heat required to melt the amount of material to be attached to the processing point. The additive manufacturing apparatus according to claim 1 or 2.

5. The beam source control unit determines the maximum output of the beam source to be the amplitude of the pulsed beam output. The additive manufacturing apparatus according to feature 4.

6. The molding unit has a processing head that emits the beam toward the workpiece to which the molten material is to be attached, The beam source control unit, in a deceleration unit that reduces the speed at which the processing head moves to a speed lower than that included in the processing conditions, converts the beam output included in the processing conditions into a pulsed beam output. The additive manufacturing apparatus according to claim 1 or 2.

7. The reduction unit includes a corner section in which the direction of the path through which the machining head moves changes. The beam source control unit synchronizes one pulse of the beam to the timing when the machining head passes through the point in the corner where the speed of the machining head is the lowest value in the corner, or when the machining head passes through the midpoint of the range in the corner where the speed of the machining head is the lowest value in the corner. The additive manufacturing apparatus according to feature 6.

8. The reduction unit includes the starting point and the ending point of the path for moving the machining head. The beam source control unit synchronizes one pulse of the beam to the timing when the processing head starts moving from the starting point and the timing when the processing head reaches the end point. The additive manufacturing apparatus according to feature 6.

9. A molding unit having a material supply unit that supplies material and a beam source that outputs a beam, and forming an object by adhering the material melted by the beam to a workpiece, A beam source control unit that generates a beam output command by converting the beam output included in the processing conditions into a pulsed beam output, thereby causing the pulsed beam to be output from the beam source, Equipped with, The molding unit has a processing head that emits the beam toward the workpiece to which the molten material is to be attached, The beam source control unit, in a deceleration unit that reduces the speed at which the processing head moves to a speed lower than that included in the processing conditions, converts the beam output included in the processing conditions into a pulsed beam output. An additive manufacturing apparatus characterized by the following features.

10. The reduction unit includes a corner section in which the direction of the path through which the machining head moves changes. The beam source control unit synchronizes one pulse of the beam to the timing when the machining head passes through the point in the corner where the speed of the machining head is the lowest value in the corner, or when the machining head passes through the midpoint of the range in the corner where the speed of the machining head is the lowest value in the corner. The additive manufacturing apparatus according to feature 9.

11. The reduction unit includes the starting point and the ending point of the path for moving the machining head. The beam source control unit synchronizes one pulse of the beam to the timing when the processing head starts moving from the starting point and the timing when the processing head reaches the end point. The additive manufacturing apparatus according to feature 9.

12. The steps include: converting the beam output included in the processing conditions into a pulsed beam output to generate a beam output command, thereby causing a pulsed beam to be output from the beam source; The process involves supplying material from a material supply unit towards the processing point of the workpiece, and forming a shape by adhering the material, which has been melted by the beam, to the workpiece. Includes, In the step of outputting the pulsed beam from the beam source, the amplitude and pulse width of the pulsed beam output are adjusted so that the amount of heat in the beam per pulse is sufficient to melt the amount of material to be attached to the processing point. An additive manufacturing method characterized by the following:

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