Shaping method and shaping device

Abstract

This shaping method for shaping a structure by forming a plurality of structural layers in a superimposed manner involves controlling the thickness distribution of a shaping material of a second structural layer formed by being superimposed on the first structural layer, by using, in combination: a first method for controlling the thickness of a shaping material in accordance with height information about a surface of a first structural layer; and a second method for controlling the thickness of the shaping material for a spatial frequency component differing from a spatial frequency component corresponding to the first method. The present invention makes it possible to improve the accuracy of the surface of the structure shaped by an additive manufacturing (AM) method.

Description

Molding method and molding device

[0001] The present invention relates to a molding method and a molding apparatus for forming a molded object by, for example, an additive manufacturing (AM) method.

[0002] For example, as a device for forming a model using an additive manufacturing (AM) method, such as a 3D printer, a modeling device is known that supplies a powdered modeling material to an area irradiated with an energy beam, melts the modeling material with the energy beam, and then re-solidifies the molten material, repeatedly stacking multiple structural layers (modeling layers) to form a model (see Patent Document 1). With such a modeling device, there is a demand for improving the surface precision of the modeled object.

[0003] US Patent Application Publication No. 2016 / 0375521

[0004] According to a first aspect of the present invention, there is provided a modeling method for forming a structure by stacking multiple structural layers, the modeling method comprising: controlling a thickness distribution of a building material of a second structural layer formed on the first structural layer by using a first method for controlling a thickness of the building material in accordance with height information of the surface of the first structural layer and a second method for controlling a thickness distribution of the building material with respect to a spatial frequency component different from the spatial frequency component corresponding to the first method; and controlling a thickness distribution of a building material of a second structural layer formed on the first structural layer by using a first method and a second method for controlling a thickness distribution of the ..., the first method including changing a relative positional relationship between a material supply unit that supplies the building material and the building surface, and the second method including controlling an intensity of a light beam irradiated onto the building material.

[0005] According to a third aspect, a modeling device is provided that forms a structure by stacking multiple structural layers, and that includes an irradiation unit that irradiates a light beam onto a modeling surface, a material supply unit that supplies modeling material to the area irradiated by the light beam, a movement unit that moves the light beam and the modeling material relative to each other, a first thickness control unit that controls the thickness of the modeling material, a second thickness control unit that controls the thickness of the modeling material at a spatial frequency higher than the spatial frequency that the first thickness control unit can handle, and a modeling control unit that uses the first and second thickness control units in combination to control the thickness distribution of the modeling material of a second structural layer that is formed on top of the first structural layer, in accordance with height information of the surface of the first structural layer.

[0006] According to a fourth aspect, a modeling device is provided that forms a structure by stacking multiple structural layers, and that includes an irradiation unit that irradiates a light beam onto a modeling surface, a material supply unit that supplies modeling material to the area irradiated with the light beam, and a modeling control unit that controls the thickness distribution of the modeling material of a second structural layer that is formed on top of the first structural layer by using a combination of first and second thickness control units that have different corresponding spatial frequency components, depending on the height information of the surface of the first structural layer, wherein the first thickness control unit is a modification unit that changes the relative positional relationship between the material supply unit and the modeling surface, and the second thickness control unit is an intensity control unit that controls the intensity of the light beam.

[0007] [Correction based on Rule 91, June 30, 2022] A cross-sectional view of a modeling apparatus according to a first embodiment. (A) is a plan view showing an example of the arrangement of multiple light projectors, and (B) and (C) are diagrams illustrating an example of the relationship between the height of the modeling surface and the spacing between two projected patterns. (A) is a diagram illustrating the case where the distance between the material nozzle and the modeling surface is at the center of the variable range, and (B) and (C) are diagrams illustrating the cases where the distance is at the longest and shortest of the variable range, respectively. (A), (B), (C), and (D) are diagrams illustrating the process of forming a convex pattern on a workpiece by irradiating the modeling material with processing light and cooling it. (A) is a cross-sectional view showing the state where a pattern on a first structure layer is formed and the height distribution of the formed pattern is measured, (B) is a diagram illustrating an example of the low spatial frequency component of the error distribution, (C) is a diagram illustrating an example of the high spatial frequency component, and (D) is a cross-sectional view showing the state where a pattern on a second structure layer is formed and the height distribution of the formed pattern is measured. 1A, 1B, and 1C are cross-sectional views showing a process for forming a line pattern as a three-dimensional structure. 1A, 1B, and 1C are cross-sectional views showing a process for forming a three-dimensional structure. 1A is a flowchart showing an example of a forming method, and 1B is a flowchart showing the operation of a modified example. 1A is a cross-sectional view showing a state in which a pattern of a second structure layer is formed while measuring the height distribution of the surface of a first structure layer in a modified example. 1B is a diagram showing an example of low spatial frequency components of the error distribution, and 1C is a diagram showing an example of high spatial frequency components. 1A is a diagram showing a case where the inclination angle of the material nozzle is at the center of the variable range, and 1B and 1C are diagrams showing cases where the inclination angle is at the maximum and minimum of the variable range, respectively. 1A is a cross-sectional view showing a state in which the height distribution of the surface of a pattern of a second structure layer is measured while measuring the height distribution of the surface of the first structure layer in a second embodiment. 1B is a diagram showing an example of low spatial frequency components of the error distribution, 1C is a diagram showing an example of high spatial frequency components, and 1D is a diagram showing an example of error distribution when feedback control is also used.

[0008] First Embodiment A first embodiment will be described below with reference to FIGS. 1 to 8. In this embodiment, a three-dimensional object is shaped (manufactured) by additive manufacturing (AM), which sequentially adds materials such as metal or synthetic resin, as in a 3D printer. Hereinafter, the additive manufacturing method will also be referred to as the AM method. In this embodiment, the AM method will be described as using laser metal deposition (LMD) (hereinafter also referred to as the LMD method), which is a type of directed energy deposition (DED) method that uses light such as laser light as an energy beam. The LMD method can also be referred to as direct metal deposition, direct energy deposition, laser cladding, laser powder deposition, laser additive manufacturing, laser rapid forming, or the like.

[0009] FIG. 1 shows a modeling apparatus 4 that is a 3D printer that uses the LMD method. In FIG. 1, the positional relationships of the various components that make up the modeling apparatus 4 will be explained using an XYZ Cartesian coordinate system defined by mutually orthogonal X, Y, and Z axes. Hereinafter, the plane formed by the X and Y axes is assumed to be parallel to the horizontal plane, and the Z axis is assumed to be perpendicular to the horizontal plane. In this case, the direction parallel to the Z axis (Z direction) is assumed to be parallel to the vertical direction, and the -Z direction is assumed to be the vertical direction.

[0010] The modeling device 4 can form a three-dimensional structure ST (see FIG. 7C ) (an object having size in all three dimensions) on a workpiece W, which serves as a base (i.e., a base material) for forming the three-dimensional structure. When the workpiece W is a stage 28, the modeling device 4 can form the three-dimensional structure ST on the stage 28. When the workpiece W is an existing structure held by the stage 28, the modeling device 4 can form the three-dimensional structure ST by adding a new structure to the existing structure. In this case, the modeling device 4 may form a three-dimensional structure ST integrated with the existing structure. Alternatively, the modeling device 4 may form a three-dimensional structure ST that can be separated from the existing structure, or may form a three-dimensional structure ST to repair a damaged portion of the existing structure. In the following, the description will be given assuming that the workpiece W is an existing structure held by the stage 28.

[0011] The modeling apparatus 4 includes an irradiation optical system 30 that irradiates the workpiece W with a light beam (hereinafter referred to as processing light) EL for modeling, a modeling head 24 having material nozzles 32A and 32B (material supply units) that supply modeling material M to the workpiece W, a drive system 26 that moves the modeling head 24, a material supply device 12, a gas supply device 18, a recovery device 22 that recovers unsolidified modeling material, and a control device 20 that controls the operation of the entire apparatus. The processing light EL generated by the light source 10 is supplied to the irradiation optical system 30 via an optical fiber 36. The control device 20 controls the intensity (energy per unit time) of the processing light EL generated by the light source 10 via a light source control unit 16. The modeling head 24, the drive system 26, and the stage 28 constitute the modeling unit 14. Note that the intensity of the processing light EL emitted from the light source 10 may be controlled using a modulation device, such as an acousto-optical element (AOM), instead of or in combination with the light source control unit 16.

[0012] The material supply device 12 supplies the material nozzles 32A, 32B of the modeling head 24 with the amount of modeling material M required per unit time for the modeling unit 14 to form the three-dimensional structure ST. The modeling material M is a material that can be melted by irradiation with processing light EL of a predetermined intensity or higher. For example, at least one of a metallic material and a resinous material can be used as the modeling material M. However, materials other than metallic materials and resinous materials may also be used as the modeling material M. The modeling material M is a powder or granular material (powder and granular material). However, the modeling material M does not have to be powder and may be, for example, a wire-shaped modeling material or a gaseous modeling material.

[0013] The modeling unit 14 processes the modeling material M supplied from the material supply device 12 to form a three-dimensional structure ST. To process the modeling material M, the modeling head 24 of the modeling unit 14 is equipped with an irradiation optical system 30 and material nozzles (supply systems that supply the modeling material M) 32A, 32B. A suction port 22a, which is connected to the recovery device 22 via a flexible pipe or the like (not shown), is supported by the modeling head 24 via a support member (not shown), for example. The modeling head 24, drive system 26, and stage 28 are housed in a space 8IN within the chamber 8.

[0014] The irradiation optical system 30 is optically connected to the light source 10 via an optical fiber 36. An optical transmission member such as a light guide can be used instead of the optical fiber 36. Note that the light emitted from the light source 10 may be directly supplied to the irradiation optical system 30. The light source 10 is, for example, a laser light source that emits laser light of at least one wavelength selected from infrared, visible, and ultraviolet as the processing light EL. However, other types of light may be used as the processing light EL. The laser light source may be a CO ２The light source 10 may be a gas laser such as a laser or excimer laser, a solid-state laser such as a neodymium-yttrium aluminum garnet (Nd:YAG) laser or an yttrium oxide (YVO4) laser, a semiconductor laser (LD) laser diode, or a fiber laser. The light source 10 may emit either continuous or pulsed light. The processing light EL does not have to be laser light, and the light source 10 may include any light source (e.g., at least one of an LED (Light Emitting Diode) or a discharge lamp). The timing and intensity of the light emission (energy per unit time) of the light source 10 are controlled by a light source control unit 16.

[0015] The irradiation optical system 30 includes a condenser lens system (not shown) that collects the processing light EL emitted from the optical fiber 36 and converts it into a parallel beam, and a focusing lens system 30a that collects the processing light EL on the printing surface CS. As an example, the printing surface CS is disposed at a focal plane (focus position) near the rear focal plane of the focusing lens system 30a, and the optical axis AX of the focusing lens system 30a is parallel to the Z axis. The irradiation optical system 30 emits the processing light EL propagated from the light source 10 via the optical fiber 36 downward (in the −Z direction) along the optical axis AX.

[0016] When a workpiece W is mounted on the stage 28, the irradiation optical system 30 irradiates the processing light EL toward the workpiece W on the stage 28. The irradiation optical system 30 is capable of irradiating the processing light EL onto an irradiation area EA set on the workpiece W. Furthermore, under the control of the control device 20, the state of the irradiation optical system 30 can be switched between a state in which the processing light EL is irradiated onto the irradiation area EA and a state in which the processing light EL is not irradiated onto the irradiation area EA. Note that the direction of the processing light EL emitted from the irradiation optical system 30 is not limited to directly downward (-Z direction) and may be, for example, a direction tilted by a predetermined angle with respect to the Z axis.

[0017] The object-forming head 24 also includes light-projecting units 44A and 44B, which are disposed on either side of the irradiation optical system 30 in the Y direction and obliquely project two circular spot lights GLA and GLB onto the object-forming surface, light-projecting units 44C and 44D, which are disposed on either side of the irradiation optical system 30 in the X direction and obliquely project two circular spot lights GLC and GLD onto the object-forming surface (see FIG. 2A), light-projecting units 44E, 44F, 44G, and 44H, which are disposed on either side of the irradiation optical system 30 in the diagonal direction and obliquely project two circular spot lights GLE, GLF, GLG, and GLH onto the object-forming surface, (see FIG. 2A), and an imaging device 46, which captures images of the spot lights GLA to GLH. Note that the number of light-projecting units 44A to 44H may be arbitrary, and the imaging device 46 may be supported by a support member separate from the object-forming head 24. The image signal from the image capture device 46 is processed by the image capture signal processor 48 to obtain a height distribution signal RS indicating the distribution of heights (positions in the Z direction or Z positions) of the printing surface or pattern at the positions where the spot lights GLA-GLH are projected (details will be described later). The light projectors 44A-44H, the image capture device 46, and the image capture signal processor 48 constitute a height measurement device 42 that measures the height distribution of the printing surface CS or the surface of the printed pattern. Also provided are an error calculation unit 50, a high-pass filter unit 52H, and a low-pass filter unit 52L for processing the height distribution signal RS (the functions of these units will be described later). The height of the printing surface or the like may be measured by any method, and for example, a proximity sensor, an air micrometer, or the like may be used.

[0018] The material nozzles 32A and 32B connected to the material supply device 12 are, for example, arranged symmetrically and tilted in the Y direction, sandwiching the irradiation optical system 30. The modeling head 24 is provided with drive mechanisms 34A and 34B for controlling the Z-direction positions of the material nozzles 32A and 32B. The number of material nozzles 32A and 32B may be three or more. The control device 20 controls the Z-direction positions of the material nozzles 32A and 32B (their relative positions in the Z direction with respect to the modeling surface CS) by driving the drive mechanisms 34A and 34B via the nozzle control unit 60. The material nozzles 32A and 32B each supply (specifically, jet, eject, or spray) the modeling material M from a supply port obliquely to the modeling surface CS. The material nozzles 32A and 32B are physically connected to the material supply device 12, which is a supply source of the modeling material M, via a flexible pipe 54 or the like. The material nozzles 32A, 32B may pressure-feed the modeling material M supplied from the material supply device 12 to the modeling surface CS via a pipe 54 or the like. That is, a mixture of the modeling material M from the material supply device 12 and a transport gas (e.g., an inert gas such as nitrogen or argon) may be pressure-feed to the material nozzles 32A, 32B via the pipe 54, and the mixture may be pressure-feed from the material nozzles 32A, 32B. Note that although the material nozzles 32A, 32B are depicted in FIG. 1 as being tubular, the shape of the material nozzles 32 is not limited to this shape.

[0019] When a workpiece W is mounted on the stage 28, the material nozzles 32A and 32B supply the building material M toward the workpiece W on the stage 28. As an example, the traveling direction of the building material M supplied from the material nozzles 32A and 32B is inclined symmetrically at a predetermined angle (e.g., an acute angle) with respect to the Z axis. In this embodiment, the material nozzles 32A and 32B supply the building material M toward the irradiation area EA onto which the irradiation optical system 30 irradiates the processing light EL. In other words, the material nozzles 32A and 32B are aligned with the irradiation optical system 30 so that the supply area MA on the workpiece W onto which the material nozzles 32A and 32B supply the building material M coincides with (or at least partially overlaps with) the irradiation area EA. Note that the material nozzles 32A and 32B may also be aligned to supply the building material M to a molten pool MP (see FIG. 6A ) formed by the processing light EL emitted from the irradiation optical system 30.

[0020] The drive system 26, which includes, for example, a motor and a position detection encoder, moves the object-forming head 24 along at least one of the X-axis, Y-axis, and Z-axis. When the object-forming head 24 moves along at least one of the X-axis and Y-axis, the irradiation area EA moves on the workpiece W along at least one of the X-axis and Y-axis. Furthermore, the drive system 26 may tilt the object-forming head 24 in at least one of the θx, θy, and θz directions, which are rotational directions around axes parallel to the X-axis, Y-axis, and Z-axis. The control device 20 is provided with a control unit 56 that controls the operation of the drive system 26. The drive system 26 may also move the irradiation optical system 30 and the material nozzles 32A and 32B separately. Specifically, for example, the drive system 26 may be capable of adjusting at least one of the position and direction of the injection portion (tip) of the irradiation optical system 30 and the position and direction of the supply ports of the material nozzles 32A and 32B. In this case, it is possible to separately control the irradiation area EA, where the irradiation optical system 30 irradiates the processing light EL, and the supply area MA, where the material nozzles 32A, 32B supply the modeling material M. The drive system 26 may be configured to rotate the modeling head 24 around an axis parallel to an axis (rotation axis) inclined with respect to axes parallel to the X-axis and Y-axis.

[0021] The stage 28 can hold and release the workpiece W via a mechanical chuck, a vacuum chuck, or the like. The stage 28 can move and / or rotate the workpiece W relative to the modeling head 24 in directions along the X-axis, Y-axis, and Z-axis, as well as in rotational directions along the θx, θy, and θz directions. The control device 20 is provided with a control unit 58 that controls the operation of the stage 28. During at least a portion of the time that the stage 28 holds the workpiece W, the irradiation optical system 30 irradiates the workpiece W with the processing light EL, and the material nozzles 32A and 32B supply the modeling material M. Note that some of the modeling material M supplied by the material nozzles 32A and 32B scatters or falls from the surface of the workpiece W to the outside of the workpiece W (e.g., toward the periphery of the stage 28), while the modeling material M that was not melted and solidified by the processing light EL remains on the stage 28 (on the workpiece W) or on the modeled layer. For this reason, the modeling device 4 is equipped with a recovery device 22 that recovers modeling material M that remains unsolidified on the stage 28 or the workpiece W (modeling layer), as well as modeling material M that has scattered or fallen around the stage 28.

[0022] The gas supply device 18 is a supply source of purge gas. The purge gas includes an inert gas (nitrogen gas, helium gas, argon gas, etc.). The gas supply device 18 supplies the purge gas into the chamber 8 via a pipe 38. As a result, the internal space 8IN of the chamber 8 becomes a space filled with the purge gas. The gas supply device 18 may be a cylinder storing the inert gas, or, if the inert gas is nitrogen gas, may be a device that separates the nitrogen gas from the atmosphere. A portion of the purge gas is also supplied from the gas supply device 18 to the material supply device 12 as needed.

[0023] The control device 20 controls the operation of the modeling apparatus 4. The control device 20 includes, for example, a central processing unit (CPU), a graphics processing unit (GPU), memory, input / output units, etc., and a storage device (storage medium) 40. As an example, 3D model data of a modeling target is output from a server (not shown) to the control device 20. The control device 20 slices the 3D model data to create modeling data for multiple structural layers. Then, during modeling of each layer, under the control of the control device 20, the control device 20 supplies the modeling material M to a supply area MA on the workpiece W, irradiates the light EL to an irradiation area EA that is at least partially the same as the supply area MA, and controls the movement of the modeling head 24 by the drive system 26 and / or the movement of the workpiece W by the stage 28, thereby modeling the structure on the workpiece W.

[0024] The control device 20 functions as a device that controls the operation of the modeling apparatus 4 by having the CPU execute a computer program. This computer program is a computer program for causing the control device 20 (e.g., the CPU) to control and execute the operations to be performed by the modeling apparatus 4. The computer program executed by the CPU may be recorded in the storage device 40 or in a storage medium connectable to the storage device 42 (e.g., a hard disk, CD-ROM, DVD-RAM, or semiconductor memory). Alternatively, the control device 20 may download the computer program to be executed from a device external to the control device 20 via a network interface. The control device 20 does not have to be installed inside the room in which the chamber 8 of the modeling apparatus 4 is installed; for example, it may be installed outside the room as a server or the like.

[0025] In this embodiment, the control device 20 controls the emission mode of the light EL from the irradiation device 10 via the light source control unit 16. The emission mode includes, for example, at least one of the intensity of the processing light EL and the emission timing of the processing light EL. When the processing light EL is pulsed light, the emission mode may include, for example, at least one of the emission frequency of the pulsed light, the emission duration of the pulsed light, and the ratio between the emission duration and the extinction duration of the pulsed light (so-called duty ratio). Furthermore, the control device 20 controls the movement mode of the modeling head 24 via the control unit 56, and the movement mode of the stage 28 via the control unit 58. The movement mode includes, for example, at least one of the movement amount, movement speed, movement direction, and movement timing. Furthermore, the control device 20 controls the supply mode of the modeling material M from the material nozzles 32A and 32B. The supply mode includes, for example, at least one of the supply amount (particularly, the supply amount per unit time), the thickness of the supplied modeling material, and the supply timing.

[0026] Next, during modeling using a typical LMD (laser build-up deposition) method (the same applies to other DED (directed energy deposition) methods), when each structural layer is modeled, the processing light EL is irradiated from the irradiation optical system 30 onto the modeling surface CS at a constant output, the material nozzles 32A and 32B supply the modeling material M to the modeling surface CS at a constant supply amount per unit time, and the driving system 26 and / or the stage 28 move the processing light EL relative to the modeling material M at a constant scanning speed. Ideally, therefore, the surface of each structural layer after modeling should be almost perfectly flat. However, in reality, the shapes, etc., of the structural layers stacked below the corresponding layer are not uniform, and therefore the heat capacity is also not uniform. Therefore, even when modeling is performed under the above-mentioned constant conditions, the heat diffusion from the processing light EL supplied to the layer is not uniform. For example, if the molten pool is large, more material will melt and the layer will be thicker, whereas if the molten pool is small, the layer will be thinner, resulting in unevenness on the surface of the structure layer after it is built. In other words, even if the build is performed under the above-mentioned constant conditions, the height distribution of the surface of each structure layer after it is built will have an error compared to the target distribution.

[0027] Therefore, in this embodiment, such height distribution errors are corrected by controlling the thickness distribution of the modeling material M supplied to the modeling surface CS and the intensity of the processing light EL, as described below. To correct the height distribution errors in this manner, it is first necessary to measure the height distribution with high precision using a height measurement device 42. As shown in FIG. 2A , two spot lights GLA-GLH are projected obliquely from multiple (eight in this example) light projectors 44A-44H of the height measurement device 42, which are arranged to surround the irradiation optical system 30, onto areas away from the irradiation area EA of the processing light EL by the irradiation optical system 30 toward the light projectors 44A-44H. The two spot lights GLA-GLH are projected so that the distance between them gradually narrows.

[0028] For this reason, as shown in FIG. 2B , when the height (Z position) of the printing surface CS onto which the spot light GLA is projected is position Zbf, the spacing between the two spot light GLA is assumed to be h2. As an example, position Zbf refers to the Z position of the focal plane (the plane where the processing light EL is most focused) for the irradiation optical system 30. In this case, when the height of the printing surface CS is lower by −Z1 (Z = Zbf − Z1) (Z1 is, for example, the upper limit of the expected amount of fluctuation), the spacing h1 between the spot light GLA is smaller than the spacing h2. When the height of the printing surface CS is higher by Z1 (Z = Zbf + Z1), the spacing h3 between the two spot light GLA is larger than the spacing h2. For this reason, if the spacing between the spot light GLA is h, the relationship between the height Z of the printing surface CS and the spacing h is expressed, for example, as follows, using the coefficients a and b: In this embodiment, the coefficients a and b and the position Zbf are obtained in advance, for example, by actual measurement, and the coefficients a and b and the position Zbf are stored in the imaging signal processing unit 48 in FIG. 1. h=a+b(Z-Zbf) (1)

[0029] The imaging signal processing unit 48 processes the imaging signal from the imaging device 46 to determine the distance h between the corresponding light spots GLA-GLH for each of the light projectors 44A-44H. Using this distance h, the coefficients a, b, and the position Zbf, the height (Z position) of the portion onto which the light spots GLA-GLH are projected can be calculated from Equation (1). For example, when the shaping head 24 (irradiation optical system 30) moves in the -Y direction relative to the shaping surface CS, the height (position Z) determined from the light spot GLA of the light projector 44A is the height of the surface of the corresponding structure layer after shaping, and the height (position Z) determined from the light spot GLB of the light projector 44B is the height of the surface of the structure layer below the corresponding structure layer. Therefore, the height of the corresponding structure layer after shaping and the height of the surface of the structure layer below can be measured by determining the height from the distance between the light spots GLA-GLH in front of or behind the shaping head 24 in the direction of movement relative to the shaping surface CS.

[0030] In this embodiment, a height distribution signal RS (a signal indicating the relationship between the relative movement direction and the height (Z position)) indicating the distribution of the measured height of the build surface CS is output from the image pickup signal processing unit 48 in Fig. 1 to the error calculation unit 50. Information on the target distribution of the height distribution on the surface of each structure layer is supplied to the error calculation unit 50 from the control device 20. The error calculation unit 50 subtracts the signal representing the target distribution from the height distribution signal RS to obtain a signal representing an error component, and supplies this signal representing the error component to the high-pass filter unit 52H and the low-pass filter unit 52L.

[0031] The high-pass filter unit 52H extracts a high spatial frequency signal HS having a spatial frequency higher than a predetermined threshold value SPF from the signal representing the error component, and the low-pass filter unit 52L extracts a low spatial frequency signal LS having a spatial frequency lower than the threshold value SPF from the signal representing the error component. The high spatial frequency signal HS and the low spatial frequency signal LS are each supplied to the control device 20. The spatial frequency threshold value SPA is, for example, 0.1 mm -1 The threshold value SPA is a value that changes depending on the relative speed between the object-forming head 24 and the workpiece W, which is determined by the drive system 26 and / or the stage 28, and is, for example, 0.05 to 0.2 mm. -1It may be about 20 to 5 mm in wavelength.

[0032] The control device 20 controls the output (intensity per unit time) of the light source 10 via the light source control unit 16 to correct errors in the height distribution of high spatial frequencies corresponding to the high spatial frequency signal HS, and controls the distance of the material nozzles 32A, 32B from the printing surface CS via the nozzle control unit 60 to correct errors in the height distribution of low spatial frequencies corresponding to the low spatial frequency signal LS. In this embodiment, as shown in FIG. 1, the material nozzles 32A, 32B are inclined symmetrically on either side of the irradiation optical system 30. In the following, it is assumed that during normal printing operations, the printing surface CS coincides with the focal plane BF of the irradiation optical system 30. Furthermore, as shown in FIG. 3A, when the material nozzles 32A, 32B are positioned at the center of their movable ranges in the Z direction by the drive mechanisms 34A, 34B, the angles of the material nozzles 32A, 32B are set so that the printing material M supplied from the material nozzles 32A, 32B overlaps the focal plane BF in a concentration region 62 by a predetermined amount below (in the −Z direction). The distance δz in the Z direction of the concentration area 62 from the focal plane BF is determined from the drive amounts of the drive mechanisms 34A and 34B.

[0033] In contrast, as shown in FIG. 3B, when the material nozzles 32A and 32B are moved in the +Z direction via the drive mechanisms 34A and 34B, and the concentration region 62 approaches the focal plane BF, the distance δz1 between the concentration region 62 and the focal plane BF becomes significantly smaller. The thickness th1 of the modeling material 64 supplied to the modeling surface CS per unit time is maximized. On the other hand, as shown in FIG. 3C, when the material nozzles 32A and 32B are moved in the -Z direction via the drive mechanisms 34A and 34B, and the concentration region 62 moves away from the focal plane BF, the distance δz2 between the concentration region 62 and the focal plane BF becomes significantly larger. The thickness th2 of the modeling material 64 supplied to the modeling surface CS per unit time is approximately half of the thickness th1.

[0034] That is, by changing the relative positions of the material nozzles 32A and 32B with respect to the printing surface CS and changing the spacing δz of the concentrated areas 62 with respect to the focal plane BF, it is possible to greatly control the thickness th of the printing material 64 supplied to the printing surface CS per unit time, and ultimately the thickness of the pattern formed on the printing surface CS. Therefore, in FIG. 3A, the spacing δz in the -Z direction of the concentrated areas 62 with respect to the focal plane BF and the thickness th of the printing material 64 supplied to the printing surface CS per unit time have the following relationship, using coefficients c and d obtained by actual measurement, for example. Note that only the portion of the printing material 64 with thickness th irradiated with the processing light EL becomes part of the structure layer after melting, cooling, and solidification. δz = c + d th (2)

[0035] The control device 20 calculates the distance δz by driving the drive mechanisms 34A and 34B, and then calculates the thickness th of the modeling material 64 supplied per unit time from the material nozzles 32A and 32B to the modeling surface CS using this distance δz and the known coefficients c and d. In other words, the control device 20 controls the Z-direction positions of the material nozzles 32A and 32B using the nozzle control unit 60, thereby controlling the thickness th of the modeling material 64 supplied to the modeling surface CS. As a result, the thickness of the modeling material pattern formed by irradiating the modeling material 64 with the processing light EL and melting, cooling, and solidifying it can also be controlled. Note that controlling the positions of the material nozzles 32A and 32B can significantly change the thickness th of the modeling material 64, thereby significantly controlling the thickness of the final pattern. However, controlling the positions of the material nozzles 32A and 32B is mechanical, and has a slow response speed, so it is not particularly suitable for controlling the height of the high spatial frequency component corresponding to the high spatial frequency signal HS. Therefore, in this embodiment, the height of the low spatial frequency component corresponding to the low spatial frequency signal LS is controlled by controlling the thickness of the modeling material by controlling the positions of the material nozzles 32A and 32B.

[0036] Next, a method for controlling the thickness of the shaping material by controlling the intensity of the processing light EL will be described with reference to FIGS. 4A to 4D. As shown in FIG. 4A, when the shaping light EL is irradiated onto the shaping surface CS of the workpiece W and the shaping material M is supplied to the irradiated area, a molten pool MP is formed on the shaping surface CS as shown in FIG. 4B. Then, as shown in FIG. 4C, a portion of the shaping material M is fused by the molten pool MP. After that, as shown in FIG. 4D, the portion corresponding to the shaping material 66 becomes a convex pattern 66A as the shaping light EL passes through and solidifies. In this case, if the intensity of the processing light EL emitted from the light source 10 is increased by the control of the light source control unit 16 in FIG. 1, the molten pool MP becomes larger like the molten pool MP1. As a result, a larger amount of the shaping material M is fused, resulting in a pattern 66B that is ultimately formed higher than the pattern 66A. Conversely, if the intensity of the processing light EL is decreased, the pattern that is ultimately formed becomes lower than the pattern 66A.

[0037] In this way, the thickness of the pattern formed on the structural layer can be controlled by controlling the intensity per unit time of the processing light EL. Furthermore, electrical (or optical) control of the intensity of the light source 10 by the light source control unit 16 can be performed faster than mechanical control of the positions of the material nozzles 32A and 32B. However, the amount of control of the thickness of the pattern formed on the structural layer by controlling the intensity of the light source 10 is smaller than the amount of control of the thickness of the pattern by mechanical control of the positions of the material nozzles 32A and 32B. Therefore, control of the intensity of the processing light EL is suitable for controlling the height of the high spatial frequency component corresponding to the high spatial frequency signal HS.

[0038] Next, an example of the operation of forming a first structure layer on a workpiece W and then forming a second structure layer thereon will be described with reference to FIGS. 5A to 5D. First, as shown in FIG. 5A, the surface of the workpiece W is irradiated with processing light EL from the irradiation optical system 30. Then, the material nozzles 32A and 32B supply the modeling material M to the area irradiated with the processing light EL. The modeling head 24 is then moved relative to the workpiece W, for example, in the −Y direction, to model a pattern of the first structure layer 68A. In this case, the target shape of the surface of the first structure layer 68A is assumed to be, for example, a flat target distribution 70A indicated by the dotted line. In this embodiment, during modeling of the first structure layer 68A, an image of the spot light GLA projected from the light projector 44A, located rearward of the irradiation optical system 30 in the scanning direction, onto the surface of the pattern immediately after modeling is captured by the imaging device 46 in FIG. 1, and the height distribution of the surface 68Aa of the pattern of the first structure layer 68A immediately after modeling is measured. In this example, an error signal is obtained by subtracting the target distribution signal in the error calculation unit 50 from the distribution signal RS output from the imaging signal processing unit 48 in Fig. 1. When this error signal is supplied to the high-pass filter unit 52H and the low-pass filter unit 52L, a low spatial frequency signal LS with a low spatial frequency (long wavelength) in Fig. 5(B) and a high spatial frequency signal HS with a high spatial frequency (short wavelength) in Fig. 5(C) are respectively supplied from the low-pass filter unit 52L and the high-pass filter unit 52H to the control device 20. The high spatial frequency signal HS in Fig. 5(C) corresponds to the fluctuation portions 69A and 69B with small wavelengths and small amplitudes in the height distribution in Fig. 5(A).

[0039] 5(D), when the second structural layer 68B is to be built up on the first structural layer 68A, the material nozzles 32A and 32B supply the building material M to the irradiation area of ​​the processing light EL. When the building head 24 is moved relative to the workpiece W, for example, in the -Y direction, the control device 20 corrects the Z positions of the material nozzles 32A and 32B via the nozzle control unit 60 using a feedforward control method to offset the error in the height distribution indicated by the low spatial frequency signal LS in FIG. 5(B). Furthermore, the control device 20 controls the output (intensity) of the light source 10 via the light source control unit 16 using a feedforward control method to offset the error in the height distribution indicated by the high spatial frequency signal HS in FIG. 5(C). Because the low spatial frequency signal LS and the high spatial frequency signal HS are measured in advance, the thickness of the building material M at each position can be controlled using a feedforward method to offset the previously measured error when building the second structural layer 68B. The target shape of the surface of the second structural layer 68B is also assumed to be, for example, a flat target distribution 70B indicated by the dotted line.

[0040] According to this control method, even if the surface 68Aa of the first structural layer 68A is highly uneven, the unevenness of the surface 68Ba after the build-up of the second structural layer 68B is reduced, improving the surface precision (flatness, etc.) after the build-up. Furthermore, during the build-up of the second structural layer 68B, an image of the spot light GLA projected from the light projector 44A, located rearward of the irradiation optical system 30 in the scanning direction, onto the surface of the pattern immediately after the build-up is captured by the imaging device 46 in FIG. 1 to measure the height distribution of the surface 68Ba of the pattern on the second structural layer 68B immediately after the build-up. Any error in this height distribution from the target distribution 70B is corrected during the build-up of a third structural layer (not shown) on the second structural layer 68B. According to this control method, even if molding is performed under certain conditions, if the height distribution of the surface of each structural layer after molding has an error distribution compared to the target distribution due to the unevenness of thermal diffusion mentioned above, the thickness distribution of the structural layer above can be controlled so as to offset the error distribution when molding the structural layer above, thereby making it possible to achieve the target accuracy in terms of the surface precision of the structure after molding.

[0041] Next, a description will be given of a modeling operation (i.e., an operation for forming a three-dimensional structure ST) performed by the modeling apparatus 4. The modeling apparatus 4 forms a three-dimensional structure ST on a workpiece W based on three-dimensional model data (e.g., Computer Aided Design (CAD) data) of the three-dimensional structure ST to be formed. The three-dimensional model data (hereinafter also referred to as 3D data) is supplied to the control device 20 of the modeling apparatus 4 from, for example, a server (not shown). Furthermore, measurement data of a three-dimensional object measured by a shape measuring device (not shown) provided in the modeling apparatus 4 or measurement data from a three-dimensional shape measuring device provided separately from the modeling apparatus 4 may be used as the 3D data. Note that, for example, the stereolithography (STL) format, the virtual reality modeling language (VRML) format, the additive manufacturing file format (AMF), or a bitmap format may be used as the 3D data. To form the three-dimensional structure ST, the modeling device 4 sequentially forms, layer by layer, a plurality of partial structures (hereinafter also referred to as structural layers) SL, which are obtained by, for example, slicing the three-dimensional structure ST along the Z direction. As a result, the three-dimensional structure ST is formed, which is a layered structure in which a plurality of structural layers SL are stacked. Below, the flow of operations for forming the three-dimensional structure ST by sequentially forming a plurality of structural layers SL will be described.

[0042] First, the operation of forming each structure layer SL will be described. Under the control of the control device 20, the modeling device 4 sets an irradiation area EA in a desired area on the modeling surface CS, which corresponds to the surface of the workpiece W or the surface of the already-formed structure layer SL, and irradiates the irradiation area EA with processing light EL from the irradiation optical system 30. In this embodiment, the focal plane (i.e., the light collection position) of the processing light EL coincides with the modeling surface CS. As a result, as shown in FIG. 6A , the processing light EL emitted from the irradiation optical system 30 forms a molten pool MP (i.e., a pool of metal melted by the light EL) in a desired area on the modeling surface CS. Furthermore, under the control of the control device 20, the modeling device 4 sets a supply area MA in a desired area on the modeling surface CS and supplies modeling material M to the supply area MA from the material nozzles 32A and 32B. Here, the supply area MA is set in the area where the molten pool MP is formed. Therefore, the modeling device 4 supplies modeling material M to the molten pool MP from the material nozzles 32A and 32B, as shown in FIG. 6B . As a result, the molding material M supplied to the molten pool MP melts. When the light EL is no longer irradiated onto the molten pool MP due to the relative movement of the molding head 24, the molten molding material M in the molten pool MP cools and solidifies again (i.e., solidifies). As a result, as shown in FIG. 6C , the solidified molding material M (part of the object) is deposited on the molding surface CS.

[0043] A series of modeling processes, including the formation of a molten pool MP by irradiating the light EL, the supply of the modeling material M to the molten pool MP, the melting of the supplied modeling material M, and the re-solidification of the molten modeling material M, are repeated while the modeling head 24 is moved relative to the modeling surface CS along the XY plane. In other words, when the modeling head 24 moves relative to the modeling surface CS, the irradiation area EA also moves relative to the modeling surface CS. Therefore, a series of modeling processes is repeated while the irradiation area EA is moved relative to the modeling surface CS along the XY plane (i.e., within a two-dimensional plane). During this process, the processing light EL is selectively irradiated onto the irradiation area EA, which is set in a region on the modeling surface CS where a model is desired to be formed, while it is not selectively irradiated onto the irradiation area EA, which is set in a region on the modeling surface CS where a model is not desired to be formed (in other words, no irradiation area EA is set in the region where a model is not desired to be formed). In other words, the modeling device 4 moves the irradiation area EA along a predetermined movement trajectory on the modeling surface CS, and irradiates the modeling surface CS with the processing light EL at a timing that corresponds to the distribution pattern of the area where a model is to be formed (i.e., the model within the structure layer SL). As a result, the molten pool MP also moves on the modeling surface CS along a movement trajectory that corresponds to the movement trajectory of the irradiation area EA. Specifically, the molten pool MP is formed sequentially in the area on the modeling surface CS that is irradiated with the processing light EL within the area along the movement trajectory of the irradiation area EA.

[0044] Furthermore, because the irradiation area EA and the supply area MA coincide with each other as described above, the supply area MA also moves on the build surface CS along a movement trajectory corresponding to the movement trajectory of the irradiation area EA. As a result, a structure layer SL corresponding to an assembly of objects made of solidified build material M is formed on the build surface CS. In other words, a structure layer SL corresponding to an assembly of objects formed on the build surface CS in a pattern corresponding to the movement trajectory of the molten pool MP is formed. Note that, when the irradiation area EA is set in an area where no object is desired to be formed, the processing light EL may be irradiated onto the irradiation area EA while the supply of the build material M is stopped. Alternatively, when the irradiation area EA is set in an area where no object is desired to be formed, the build material M may be supplied to the irradiation area EL while the light EL with an intensity sufficient to prevent the formation of a molten pool MP may be irradiated onto the irradiation area EL.

[0045] The movement trajectory of the irradiation area EA on the workpiece W may be either a movement trajectory corresponding to scanning by so-called raster scanning or a movement trajectory corresponding to scanning by so-called vector scanning. In the above description, the irradiation area EA is moved relative to the printing surface CS by moving the printing head 24 (i.e., the light EL) relative to the printing surface CS, but the printing surface CS may be moved, or both the printing head 24 (i.e., the processing light EL) and the printing surface CS may be moved.

[0046] Next, an example of the modeling operation of the modeling apparatus 4 of this embodiment will be described with reference to the flowchart in Fig. 8(A). First, in step 102, the control device 20 slices the three-dimensional model data at the layer pitch to create slice data and stores it in the storage device 40. Note that this slice data may be partially modified depending on the characteristics of the modeling apparatus 4. Then, the control device 20 reads modeling pattern data for the next structure layer to be modeled. In the next step 104, the control device 20 causes the light source 10 to start emitting processing light EL via the light source control unit 16.

[0047] In the next step 106, the supply of the modeling material M from the material nozzles 32A and 32B is started, and in step 108, the driving system 26 and / or the stage 28 move the processing light EL (light beam) and the modeling material M relative to each other, thereby performing modeling by build-up. In addition, in parallel with the operations of steps 106 and 108, in step 110, the height distribution of the surface of the portion (pattern) modeled by this structural layer is measured using the height measurement device 42, as in FIG. 5(A).

[0048] In the next step 112, it is determined whether the formation of this layer is complete. If the formation is not complete, the operations of steps 106 and 108 and step 110 are executed in parallel. When the formation of this layer is complete in step 112, the supply of the formation material is stopped, and the light source 10 stops emitting light. As a result, the first structure layer SL#1 is formed on the formation surface CS corresponding to the surface of the workpiece W, as shown in FIG. 7A, for example. Then, the process proceeds to step 114, where the error calculation unit 50 calculates an error distribution signal from the height distribution signal RS of the formed structure layer. Furthermore, in step 116, the error distribution signal is supplied to the low-pass filter unit 52L and the high-pass filter unit 52H, which extract a low spatial frequency signal LS and a high spatial frequency signal HS, respectively. The extracted signals LS and HS are stored in the storage device 40.

[0049] In the next step 118, the control device 20 reads the shaping pattern data for the next structure layer to be shaped. Then, as shown in FIG. 7B , the surface of the structure layer SL#1 is set as a new shaping surface CS, and the second structure layer SL#2 is formed on this new shaping surface CS. In this case, the control device 20 first controls the drive system 26 to move the shaping head 24 along the Z axis. Specifically, the control device 20 controls the drive system 26 to move the shaping head 24 in the +Z direction so that the irradiation area EA and the supply area MA are set on the surface of the structure layer SL#1 (i.e., the new shaping surface CS). This causes the focal plane of the processing light EL to coincide with the new shaping surface CS.

[0050] Next, similar to the modeling of the first structure layer, the following steps are performed: correction of low spatial frequency components by controlling the Z positions of the material nozzles 32A and 32B in step 120; correction of high spatial frequency components by controlling the output of the processing light EL emitted from the light source 10 in step 122; and modeling by relative movement of the processing light EL and the modeling material M in step 124. Note that the operations of steps 120, 122, and 124 are performed substantially in parallel. Furthermore, in parallel with the operations of steps 120 to 124, in step 126, similar to step 110, the height distribution of the surface of the portion (pattern) modeled by this structure layer is measured using the height measurement device 42. Note that in step 120, when controlling the Z positions of the material nozzles 32A and 32B to control the thickness of the modeling material supplied to the modeling surface CS, the output (intensity per unit time) of the processing light EL may be set, for example, to an output that can melt the entire thickness of the modeling material supplied to the modeling surface CS when the thickness is at its thickest. As another example, the output of the processing light EL may be set to an output that can melt the shaping material of a thickness that is the median of the thickness range of the shaping material, and when the thickness of the shaping material is controlled by controlling the Z position of the material nozzles 32A and 32B, the output of the processing light EL may be increased or decreased depending on the thickness. Then, in step 124, even if the thickness of the shaping material supplied is constant, the thickness of the shaping material after shaping can be controlled within a certain range by controlling the output of the processing light EL.

[0051] Thereafter, in step 128, if the modeling of this layer is not completed, the operations of steps 120 to 124 and step 126 are repeated. If the modeling of this layer is completed, the operation proceeds to step 130, where it is determined whether the modeling is completed. If the modeling is not completed, the operation proceeds to step 114, where the next structural layer is modeled while correcting the thickness distribution of the modeling material to correct the error in the height distribution of the previous layer. In this way, as shown in FIG. 7C , a three-dimensional structure ST is formed by a layered structure in which multiple structural layers SL are stacked. In this modeling method, the height distribution after modeling is measured during the modeling of the previous layer, and the thickness of the modeling material is controlled during the modeling of the next layer to offset the error distribution in the height distribution of the previous layer, thereby improving the surface precision (flatness, etc.) of the structure after modeling.

[0052] As described above, the modeling method of the modeling apparatus 4 of this embodiment is a modeling method for forming a structure by stacking multiple structural layers, and uses a first method (a method of controlling the Z position of the material nozzles 32A, 32B) for controlling the thickness of the modeling material in accordance with the height distribution signal RS (height information) on the surface of the first structural layer 68A, and a second method (a method of controlling the intensity of the processing light EL) for controlling the thickness of the modeling material for spatial frequency components higher than the spatial frequency components corresponding to the first method, to control the thickness distribution of the modeling material of the second structural layer 68B formed on top of the first structural layer 68A (steps 120, 122, 124).

[0053] The modeling apparatus 4 of this embodiment is a modeling apparatus that forms a structure by stacking multiple structural layers, and includes an irradiation optical system 30 (irradiation unit) that irradiates a modeling surface with processing light EL (light beam), material nozzles 32A, 32B (material supply unit) that supply modeling material M to the area irradiated with the processing light EL, a drive system 26 and a stage 28 (movement unit) that relatively move the processing light EL and the modeling material M, and drive mechanisms 34A, 34B and a nozzle control unit 60 (hereinafter referred to as a nozzle control unit) that control the Z positions of the material nozzles 32A, 32B to control the thickness of the modeling material. , also referred to as the first thickness control unit), a light source control unit 16 (hereinafter also referred to as the second thickness control unit) that controls the intensity of the processing light EL to control the thickness of the modeling material at a spatial frequency higher than the spatial frequency that the first thickness control unit can handle, and a control device 20 (hereinafter also referred to as the modeling control unit) that uses the first thickness control unit and the second thickness control unit in combination to control the thickness distribution of the modeling material of the second structure layer 68B formed on top of the first structure layer 68A in accordance with a height distribution signal RS (height information) of the surface of the first structure layer 68A.

[0054] According to this embodiment, the thickness (deposition amount) of the build material is controlled during build-up of the second structural layer 68B to offset (correct) the error distribution in the height distribution on the surface of the first structural layer 68A. Therefore, even if the height distribution on the surface of the first structural layer 68A deviates from the target distribution due to non-uniform thermal diffusion or the like during build-up of the first structural layer 68A, the surface precision (flatness, etc.) of the second structural layer 68B can be improved by controlling the thickness distribution of the build material during build-up of the second structural layer 68B. Furthermore, since low spatial frequency components are corrected by controlling the distance between the material nozzles 32A and 32B and the build surface CS, and high spatial frequency components are corrected by controlling the intensity of the processing light EL emitted from the light source 10, errors with large amplitudes can be corrected with high precision over a wide spatial frequency range, even in low spatial frequency ranges. The thickness distribution includes not only the distribution of surface irregularities but also the distribution of the thickness itself. For example, by smoothing the unevenness distribution as the thickness distribution, it is possible to improve the surface precision (flatness, etc.) of the surface of the structure. Also, by controlling the thickness distribution of the modeling material to a target distribution as the thickness distribution, it is possible to model a structure layer with a desired thickness distribution or a uniform film thickness distribution.

[0055] Furthermore, in this embodiment, the height distribution of the surface of the pattern on the first structural layer 68A after modeling is measured by the height measurement device 42 simultaneously during modeling of the first structural layer 68A, and this measurement result is used during modeling of the pattern on the next second structural layer 68B. Therefore, modeling can be performed more efficiently than when the height distribution of the surface of the pattern on the first structural layer 68A is measured separately. However, a measurement process for measuring the height distribution of the surface of the first structural layer 68A may be provided between the modeling process of the first structural layer 68A and the modeling process of the second structural layer 68B.

[0056] 8A in the above-described embodiment, the height distribution of the surface of the portion where the modeling of the corresponding structure layer has been completed is measured. In contrast, as a modification of the above-described embodiment, in step 126A in FIG. 8B, as shown in FIG. 9A, during modeling of the second structure layer 68B, an image of a spot light GLB projected onto the surface of the first structure layer 68A from a light projector 44B located forward in the scanning direction from the irradiation optical system 30 in the modeling head 24 may be captured by the imaging device 46 in FIG. 1 to measure the height distribution of the pattern on the surface 68Aa of the first structure layer 68A. In this modification, in the next step 114A, an error distribution signal of the height distribution of the surface 68Aa of the first structure layer 68A is obtained, and in the next step 116A, a low spatial frequency signal LS and a high spatial frequency signal HS are extracted from the error distribution signal.

[0057] Furthermore, in this modified example, the operations of steps 126A, 114A, and 116A are performed on an area in front of the area in Fig. 9A where the processing light EL is irradiated and the modeling material M is supplied from the modeling head 24. For example, in Fig. 9A, if the position in the Y direction where the processing light EL is irradiated from the irradiation optical system 30 is Y2, in step 116A, the low spatial frequency signal LS and the high spatial frequency signal HS are obtained up to position Y1 in front of position Y2, as shown in Figs. 9B and 9C.

[0058] 8B, the second structural layer 68A can be modeled while correcting the thickness of the modeling material of the second structural layer 68B using a feedforward method so as to offset the error distribution of the surface of the first structural layer 68A calculated in step 116A. In other words, this modification allows measurement of the height distribution of the surface of the previous layer and control of the thickness of the modeling material of that layer in almost real time using the measurement results. Therefore, there is no need to measure and store the height distribution of the surface of the previous layer in advance during modeling of the previous layer.

[0059] In the above-described embodiment, the low spatial frequency components of the height distribution error distribution are corrected by controlling the Z-direction positions of the material nozzles 32A and 32B. However, as shown in the modified examples of FIGS. 10A to 10C, the error distribution may be corrected by controlling the angles of the material nozzles 32A and 32B. In FIG. 10A, the material nozzles 32A and 32B that supply the modeling material M are symmetrically arranged on the modeling head 24, sandwiching the irradiation optical system 30. In this modified example, the material nozzles 32A and 32B are rotatably supported relative to the modeling head 24. Furthermore, drive mechanisms 34C and 34D are provided for rotating the material nozzles 32A and 32B relative to the modeling head 24. The remaining configuration is the same as that of the above-described embodiment.

[0060] In the following, it is assumed that in normal modeling operations, the modeling surface CS coincides with the focal plane BF of the irradiation optical system 30. As shown in Fig. 10A, when the material nozzles 32A, 32B are located in the center of their movable rotation ranges by the drive mechanisms 34C, 34D, the angles of the material nozzles 32A, 32B are set so that the modeling material M supplied from the material nozzles 32A, 32B overlaps the focal plane BF in a concentration region 62 that is a predetermined amount below (in the -Z direction). The distance in the Z direction between the concentration region 62 and the focal plane BF can be calculated from the drive amount of the drive mechanisms 34A, 34B.

[0061] In contrast, as shown in FIG. 10B, when the material nozzles 32A and 32B are rotated toward the irradiation optical system 30 via the drive mechanisms 34C and 34D, and the concentrated area 62 approaches the focal plane BF, the distance between the concentrated area 62 and the focal plane BF becomes significantly smaller. The thickness th1 of the modeling material 64 supplied to the modeling surface CS per unit time becomes larger. On the other hand, as shown in FIG. 10C, when the material nozzles 32A and 32B are rotated away from the irradiation optical system 30 via the drive mechanisms 34C and 34D, and the concentrated area 62 moves away from the focal plane BF, the distance between the concentrated area 62 and the focal plane BF becomes significantly larger. The thickness th2 of the modeling material 64 supplied to the modeling surface CS per unit time becomes approximately half of the thickness th1.

[0062] That is, by changing the rotation angle of the material nozzles 32A and 32B and thereby changing the distance between the concentration areas 62 and the focal plane BF, the thickness th of the modeling material 64 supplied to the modeling surface CS per unit time can be controlled to a large extent. This allows for significant control of the thickness distribution of the pattern ultimately formed on the modeling surface CS. The control device 20 in FIG. 1 calculates the distance by driving the drive mechanisms 34C and 34D, and from this distance, calculates the thickness th of the modeling material 64 supplied per unit time from the material nozzles 32A and 32B to the modeling surface CS. In other words, the control device 20 controls the rotation angle of the material nozzles 32A and 32B using the nozzle control unit 60 to control the thickness th of the modeling material 64 supplied to the modeling surface CS. As a result, the thickness of the modeling material pattern formed by irradiating the modeling material 64 with the processing light EL and melting, cooling, and solidifying it can also be controlled. The rotation control of the material nozzles 32A and 32B is a mechanical control, and the response speed is not very high, but the control range of the thickness of the modeling material is wide. Therefore, by controlling the rotation of the material nozzles 32A and 32B, it is possible to control the thickness of the modeling material with low spatial frequency components and a wide correction range.

[0063] In the above-described embodiment and its modified examples, the thickness of the modeling material M supplied to the modeling surface CS is controlled by controlling the relative positions of the material nozzles 32A, 32B and the modeling surface CS. Alternatively, the thickness of the modeling material M supplied from the material nozzles 32A, 32B to the modeling surface CS may be controlled by controlling the amount of modeling material supplied per unit time from the material supply device 12 to the material nozzles 32A, 32B. When controlling the amount of modeling material supplied per unit time from the material supply device 12 to the material nozzles 32A, 32B, only one of the material nozzles 32A, 32B (e.g., 32A) may be provided.

[0064] Second Embodiment Next, a second embodiment will be described with reference to FIG. 11 . The modeling apparatus 4 of FIG. 1 is also used in this embodiment, but the method for controlling the thickness distribution of the modeling material of the structure layer is different. In this embodiment, an example of the operation of forming a first structure layer on a workpiece W and then forming a second structure layer thereon will be described with reference to FIGS. 11A to 11D . First, as shown in FIG. 11A , a first structure layer 68A is formed on the surface of the workpiece W using the modeling apparatus 4. At this time, it is not necessarily necessary to measure the height distribution of the surface 68Aa of the first structure layer 68A. Next, processing light EL is irradiated onto the first structure layer 68A from the irradiation optical system 30, and modeling material M is supplied from the material nozzles 32A and 32B to the area irradiated with the processing light EL. The modeling head 24 is then moved relative to the workpiece W, for example, in the −Y direction, to deposit and model the pattern of the second structure layer 68B. In this case, the target shapes of the surfaces of the first structural layer 68A and the second structural layer 68B are assumed to be flat target profiles 70A and 70B, respectively, as indicated by dotted lines, for example.

[0065] During the modeling of the second structural layer 68B, the image of the spot light GLB projected onto the surface 68Aa of the first structural layer 68A from the light projector 44B located forward in the scanning direction from the irradiation optical system 30 in the modeling head 24 is captured by the imaging device 46 shown in FIG. 1 to measure the height distribution of the pattern on the surface 68Aa of the first structural layer 68A, which is the preceding layer. The error calculation unit 50 then subtracts the target distribution signal from the height distribution signal RS to obtain an error signal. This error signal is supplied to the high-pass filter unit 52H and the low-pass filter unit 52L, which then supply the low-spatial frequency signal LS shown in FIG. 11B and the high-spatial frequency signal HS shown in FIG. 11C, respectively, to the control device 20.

[0066] 11A, if the position in the Y direction at which the processing light EL is irradiated from the irradiation optical system 30 is Y4, then by capturing an image of the spot light GLB, the low spatial frequency signal LS and the high spatial frequency signal HS are obtained up to position Y3 in front of position Y4, as shown in FIGS. 11B and 11C. Therefore, by using the low spatial frequency signal LS and the high spatial frequency signal HS to control the Z direction positions of the material nozzles 32A, 32B and the intensity of the processing light EL, it is possible to control the thickness distribution of the modeling material in a feedforward manner in substantially real time during modeling of the second structural layer 68B so as to cancel out errors in the height distribution of the surface of the first structural layer 68A.

[0067] 11A, in the present embodiment, during build-up molding of the second structural layer 68B, an image of the spot light GLA projected from the light projector 44A, which is located rearward in the scanning direction from the irradiation optical system 30 in the modeling head 24, onto the surface of the pattern immediately after modeling is also measured by the imaging device 46 in FIG. 1, and the height distribution of the surface 68Ba of the pattern of the second structural layer 68B immediately after modeling is also measured. In this case, by controlling the thickness distribution of the modeling material of the second structural layer 68B based on the measured value of the height distribution of the surface of the first structural layer 68A, the surface 68Ba of the pattern formed so far on the second structural layer 68B approaches the target distribution 70B, but there is still a slight error.

[0068] As an example, the signal HB corresponding to the error contains only low spatial frequency components, as shown by the curve 71A in FIG. 11D. In this case, if the position of the irradiation optical system 30 is Y4, the signal HB is measured up to a rear position Y5 in the scanning direction of the irradiation optical system 30. Therefore, in this embodiment, the Z positions of the material nozzles 32A and 32B are controlled by feedback control so as to cancel out the error in the height distribution corresponding to the signal HB. Through this control, the signal HB, which indicates the error in the height distribution of the surface 68Ba of the pattern formed on the second structure layer 68B relative to the target distribution 70B, becomes smaller, as shown by the dotted curve 71B in FIG. 11D.

[0069] As described above, according to this embodiment, the thickness distribution of the modeling material of the second structural layer 68B is controlled by a feedforward method so as to offset the measurement results of the error distribution of the height distribution on the surface of the first structural layer 68A, and the thickness distribution of the modeling material of the second structural layer 68B is controlled by a feedback method so as to offset the measurement results of the error distribution of the height distribution on the surface of the pattern formed up to that point on the second structural layer 68B. Therefore, even if the error in the height distribution on the surface of the first structural layer 68A is large, the surface precision of the pattern on the second structural layer 68B can be formed with higher accuracy.

[0070] In this embodiment, when controlling the thickness distribution of the building material of the second structure layer 68B using a feedback method, a low spatial frequency signal LS and a high spatial frequency signal HS may be extracted from a signal HB indicating the error of the height distribution of the pattern surface 68Ba of the second structure layer 68B relative to the target distribution 70B. The thickness distribution includes not only the surface unevenness distribution but also the thickness distribution itself. By controlling the Z position of the material nozzles 32A and 32B using the low spatial frequency signal LS and controlling the intensity of the processing light EL using the high spatial frequency signal HS, the surface of the second structure layer 68B can be manufactured with higher surface accuracy. Furthermore, when controlling the thickness distribution itself, it is possible to manufacture the target structure layer with the desired thickness distribution and uniform film thickness.

[0071] Furthermore, the modeling apparatus 4 in each of the above-described embodiments uses laser deposition deposition (LMD), a type of directed energy deposition (DED). The above-described embodiments and their variations can also be applied to cases where a modeling apparatus using a directed energy deposition (DED) method other than LMD (e.g., a method using arc plasma or an electron beam as a heat source other than laser light) is used instead of the modeling apparatus 4. Furthermore, the configuration of the modeling apparatus 4 in the above-described embodiments is not limited to the above-described configuration and can be any other configuration. For example, the number and arrangement of the material nozzles 32A, 32B are arbitrary, and the configuration of the height measurement device 42 and the like may also be arbitrary. Furthermore, the height measurement device 42 can also be one that projects a light-dark pattern.

[0072] The present specification also describes the following aspects of the invention: 1) A modeling method for forming a structure by stacking multiple structural layers, the method controlling a thickness distribution of a modeling material of a second structural layer formed on the first structural layer by using a first method for controlling a thickness of a modeling material in accordance with height information of the surface of a first structural layer in combination with a second method for controlling the thickness of a modeling material with respect to a spatial frequency component different from the spatial frequency component corresponding to the first method. 2) A modeling method for forming a structure by stacking multiple structural layers, the method controlling a thickness distribution of a modeling material of a second structural layer formed on the first structural layer by using a first method and a second method for controlling a thickness distribution of a modeling material of a second structural layer formed on the first structural layer in combination with height information of the surface of the first structural layer in combination with a first method and a second method for controlling a thickness distribution of a modeling material of a second structural layer formed on the first structural layer in accordance with height information of the surface of the first structural layer in combination with a first method and a second method for controlling a thickness distribution of a modeling material of a second structural layer formed on the first structural layer in combination, the first method including changing a relative positional relationship between a material supply unit that supplies the modeling material and a modeling surface, and the second method including controlling an intensity of a light beam irradiated onto the modeling material. 3) The modeling method described in 1 or 2 (or 1), in which the first method controls the thickness distribution of the modeling material of the second structure layer so as to correct low-frequency components related to spatial frequency among height information of the surface of the first structure layer, and the second method controls the thickness distribution of the modeling material of the second structure layer so as to correct high-frequency components related to spatial frequency among the height information. 4) The modeling method described in any one of 1 to 3 (or 1), in which the first method and the second method are used in combination in a feedforward manner using height information of the surface of the first structure layer to control the thickness distribution of the modeling material of the second structure layer. 5) The modeling method described in any one of 1 to 4 (or 1), in which forming the second structure layer includes supplying modeling material from a material supply unit to an area irradiated with a light beam and moving the light beam and the modeling material relatively, and the first method includes controlling the thickness of the modeling material supplied from the material supply unit to the modeling surface when moving the light beam and the modeling material relatively. 6) The modeling method according to 5, wherein the first method includes controlling a distance between the material supply unit and the modeling surface. 7) The modeling method according to 5, wherein supplying the modeling material from the material supply unit includes supplying the modeling material obliquely from a plurality of material supply units, and the first method includes controlling an angle of the material supply unit.

[0073] 8) The modeling method described in any one of items 1 to 7 (or 1), wherein forming the second structural layer includes supplying a modeling material from a material supply unit to an area where a light beam is irradiated, and moving the light beam and the modeling material relatively, and the second method includes controlling the intensity of the light beam. 9) The modeling method described in any one of items 1 to 8 (or 1), wherein, when forming the second structural layer, measuring height information of the surface of the first structural layer in an area before the modeling material of the second structural layer is applied. 10) The modeling method described in any one of items 1 to 8 (or 1), wherein, when forming the first structural layer, measuring height information of the surface of the first structural layer in an area after the modeling material of the first structural layer has been applied. 11) The modeling method described in any one of items 1 to 8 (or 1), wherein, between the step of forming the first structural layer and the step of forming the second structural layer, measuring height information of the surface of the first structural layer. 12) The method for forming the second structure layer according to any one of claims 1 to 11 (or 1), wherein the method includes, when forming the second structure layer, measuring height information of the surface of the second structure layer in a region where the modeling material is applied, and controlling the thickness of the modeling material in a region of the second structure layer where the modeling material is next applied, using the first method and the second method in combination, depending on an error between a measurement result of the height information of the surface of the region where the modeling material is applied and a target distribution. 13) The method for forming the second structure layer according to any one of claims 1 to 12, wherein the height information of the surface of the first structure layer includes an error distribution of the height distribution of the surface with respect to a target distribution. 14) A modeling device that forms a structure by stacking multiple structural layers, comprising: an irradiation unit that irradiates a light beam onto a modeling surface; a material supply unit that supplies modeling material to the area irradiated with the light beam; a movement unit that moves the light beam and the modeling material relatively; a first thickness control unit that controls the thickness of the modeling material; a second thickness control unit that controls the thickness of the modeling material at a spatial frequency higher than the spatial frequency that the first thickness control unit can handle; and a modeling control unit that uses the first and second thickness control units in combination to control the thickness distribution of the modeling material of a second structural layer formed on top of the first structural layer in accordance with height information of the surface of the first structural layer.15) A modeling device that forms a structure by stacking multiple structural layers, comprising: an irradiation unit that irradiates a light beam onto a modeling surface; a material supply unit that supplies modeling material to the area irradiated with the light beam; and a modeling control unit that controls the thickness distribution of the modeling material of a second structural layer that is formed on top of the first structural layer using a combination of first and second thickness control units that have different corresponding spatial frequency components, depending on height information of the surface of the first structural layer; wherein the first thickness control unit is a change unit that changes the relative positional relationship between the material supply unit and the modeling surface, and the second thickness control unit is an intensity control unit that controls the intensity of the light beam.

[0074] 16) The modeling apparatus described in 14 or 15 (or 14), further comprising a calculation unit that extracts low-frequency components and high-frequency components related to spatial frequency from height information of the surface of the first structure layer, wherein the modeling control unit controls the thickness distribution of the modeling material of the second structure layer using the first thickness control unit to correct the low-frequency components, and controls the thickness distribution of the modeling material of the second structure layer using the second thickness control unit to correct the high-frequency components. 17) The modeling apparatus described in any one of 14 to 16 (or 14), wherein the modeling control unit controls the first thickness control unit and the second thickness control unit in a feedforward manner using height information of the surface of the first structure layer, to control the thickness distribution of the modeling material of the second structure layer. 18) The modeling apparatus described in any one of 14 to 17 (or 14), wherein the first thickness control unit controls the thickness of the modeling material supplied from the material supply unit to the modeling surface. 19) The modeling apparatus described in any one of 14 to 18 (or 14), wherein the first thickness control unit controls the distance between the material supply unit and the modeling surface. 20) The modeling apparatus described in any one of items 14 to 18 (or 14), wherein the material supply unit has a plurality of material supply units that each supply modeling material obliquely, and the first thickness control unit controls angles of the plurality of material supply units. 21) The modeling apparatus described in any one of items 14 to 20 (or 14), wherein the second thickness control unit controls intensity of the light beam. 22) The modeling apparatus described in any one of items 14 to 21 (or 14), comprising: a measurement unit that measures the height of the surface of the structure layer; and a memory unit that stores height information of the surface of the structure layer measured by the measurement unit. 23) The modeling apparatus described in 22, wherein the measurement unit has a measurement light irradiation unit that irradiates a plurality of measurement light beams obliquely onto the surface of the structure layer, an imaging unit that receives the measurement light reflected by the structure layer, and an imaging signal processing unit that processes the imaging signal of the imaging unit to determine the height of the portion of the structure layer that is irradiated with the measurement light.24) The molding apparatus described in 22 or 23 (or 22), wherein the measurement unit measures height information of the surface of the second structure layer in a region where the molding material is applied when forming the second structure layer, and the molding control unit controls the thickness of the molding material in a region where the molding material is next applied in the second structure layer using the first and second thickness control units according to the height information of the surface of the second structure layer measured by the measurement unit. 25) The molding apparatus described in any one of 14 to 24, wherein the height information of the surface of the first structure layer includes an error distribution of the height distribution of the surface with respect to a target distribution.

[0075] W...workpiece, EL...processing light, M...modeling material, 4...modeling device, 10...light source, 12...material supply device, 16...light source control unit, 18...gas supply device, 20...control device, 26...drive system, 28...stage, 30...irradiation optical system, 32A, 32B...material nozzle, 34A, 34B...drive mechanism, 42...height measurement device, 44A to 44H...light projecting unit, 46...imaging device, 48...imaging signal processing unit, 50...error calculation unit, 52H...high-pass filter unit, 52L...low-pass filter unit, 60...nozzle control unit

Claims

1. A method for forming a structure by stacking a plurality of structural layers, comprising the steps of: A molding method that controls the thickness distribution of the molding material of a second structure layer formed on top of the first structure layer by combining a first method of controlling the thickness of the molding material in accordance with height information of the surface of a first structure layer and a second method of controlling the thickness of the molding material with respect to a spatial frequency component different from the spatial frequency component corresponding to the first method.

2. Controlling a thickness distribution of the modeling material of the second structure layer by the first method so as to correct low frequency components related to spatial frequencies among height information of the surface of the first structure layer; The modeling method according to claim 1 , wherein the second method controls a thickness distribution of the modeling material of the second structure layer so as to correct high frequency components related to spatial frequencies of the height information.

3. The molding method described in claim 1, wherein the thickness distribution of the molding material of the second structure layer is controlled by using height information of the surface of the first structure layer in a feedforward manner by combining the first method and the second method.

4. forming the second structure layer includes supplying a modeling material from a material supply unit to an area irradiated with a light beam, and moving the light beam and the modeling material relative to each other; The molding method according to claim 1 , wherein the first method includes controlling a thickness of the molding material supplied from the material supply unit to the molding surface when the light beam and the molding material are moved relative to each other.

5. The molding method according to claim 4 , wherein the first method includes controlling a distance between the material supply unit and a molding surface.

6. Supplying the modeling material from the material supply unit includes supplying the modeling material in an oblique direction from a plurality of material supply units; The method of claim 4 , wherein the first method includes controlling an angle of the material supply unit.

7. forming the second structure layer includes supplying a modeling material from a material supply unit to an area irradiated with a light beam, and moving the light beam and the modeling material relative to each other; The method of claim 1 , wherein the second method comprises controlling an intensity of the light beam.

8. The molding method according to claim 1 , further comprising measuring height information of the surface of the first structure layer in an area of ​​the second structure layer before the molding material is applied when forming the second structure layer.

9. The molding method according to claim 1 , further comprising measuring height information of the surface of the first structure layer in an area after the molding material of the first structure layer is applied when forming the first structure layer.

10. Between the step of forming the first structure layer and the step of forming the second structure layer, The modeling method according to claim 1 , further comprising the step of measuring height information of the surface of the first structure layer.

11. When forming the second structure layer, measuring height information of a surface of the second structure layer in a region where a modeling material of the second structure layer is piled; The molding method of claim 1, further comprising: using the first method and the second method in combination to control the thickness of the molding material in the area of ​​the second structure layer where the molding material is next applied, depending on the error between the measurement result of surface height information of the area where the molding material is applied and a target distribution.

12. The modeling method according to claim 1 , wherein the height information of the surface of the first structure layer includes an error distribution of the height distribution of the surface with respect to a target distribution.

13. A molding apparatus for forming a structure by stacking a plurality of structural layers, comprising: An irradiation unit that irradiates a light beam onto a modeling surface; a material supply unit that supplies a modeling material to an area irradiated with the light beam; a moving unit that moves the light beam and the modeling material relative to each other; A first thickness control unit that controls a thickness of the building material; A second thickness control unit controls the thickness of the modeling material at a spatial frequency higher than the spatial frequency that the first thickness control unit can handle; a modeling control unit that controls a thickness distribution of a modeling material of a second structure layer formed on the first structure layer by using the first and second thickness control units in combination in accordance with height information of a surface of the first structure layer; A molding apparatus comprising:

14. a calculation unit that extracts low frequency components and high frequency components related to spatial frequencies from height information of the surface of the first structure layer, The molding apparatus of claim 13, wherein the molding control unit uses the first thickness control unit to control the thickness distribution of the molding material of the second structural layer to correct the low frequency components, and uses the second thickness control unit to control the thickness distribution of the molding material of the second structural layer to correct the high frequency components.

15. The molding control unit controls the first thickness control unit and the second thickness control unit in a feedforward manner using height information of the surface of the first structure layer to control the thickness distribution of the molding material of the second structure layer.

16. The molding apparatus according to claim 13 , wherein the first thickness control unit controls a thickness of the molding material supplied from the material supply unit to the molding surface.

17. The molding apparatus according to claim 13 , wherein the first thickness control unit controls a distance between the material supply unit and a molding surface.

18. The material supply unit includes a plurality of material supply units each of which supplies a modeling material obliquely, The molding apparatus according to claim 13 , wherein the first thickness control unit controls angles of the plurality of material supply units.

19. The molding apparatus of claim 13 , wherein the second thickness control controls an intensity of the light beam.

20. A measuring unit that measures the height of a surface of the structure layer; a storage unit that stores height information of the surface of the structure layer measured by the measurement unit; The molding apparatus of claim 13 .

21. The molding apparatus described in claim 20, wherein the measurement unit includes a measurement light irradiation unit that irradiates multiple measurement light beams obliquely onto the surface of the structural layer, an imaging unit that receives the measurement light reflected by the structural layer, and an imaging signal processing unit that processes the imaging signal of the imaging unit to determine the height of the portion of the structural layer where the measurement light is irradiated.

22. The measuring unit measures height information of a surface of the second structure layer in a region where a modeling material of the second structure layer is piled up when the second structure layer is formed, The molding control unit uses the first and second thickness control units to control the thickness of the molding material in the area of ​​the second structure layer where the molding material is to be applied next, in accordance with height information of the surface of the second structure layer measured by the measurement unit.

23. The molding apparatus according to claim 13 , wherein the height information of the surface of the first structure layer includes an error distribution of the height distribution of the surface with respect to a target distribution.