Additive manufacturing system

Abstract

To provide a lamination molding system capable of achieving simplified control.SOLUTION: A lamination molding system according to one embodiment comprises a nozzle, a moving unit, a measuring unit, and a control unit. The nozzle discharges a powder and then emits an energy beam to melt or sinter the powder, thereby forming a plurality of layers stacked in a laminating direction from the powder. The moving unit moves the nozzle. The measuring unit measures a distance between the nozzle and the one of the plurality of layers formed. The control unit controls the moving unit to move the nozzle in the laminating direction based on the measured distance.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] Embodiments of the present invention relate to a layered manufacturing system.

Background Art

[0002] A layered manufacturing apparatus, for example, supplies a powdery material from a nozzle and irradiates a laser beam to melt or sinter the material to form a layer of the solidified material. The layered manufacturing apparatus forms a three-dimensional object by laminating the layers of the solidified material.

[0003] The layered manufacturing apparatus moves the nozzle based on, for example, an NC program. The NC program moves the nozzle in the height direction every time the layered manufacturing apparatus forms one layer. However, the moving distance of the nozzle in the height direction set in the NC program may be different from the thickness of the layer actually formed by the layered manufacturing apparatus. In order to make the actual layer thickness and the moving distance of the nozzle in the NC program closer to each other, the layered manufacturing apparatus performs various controls such as parameter changes and recalculation of the nozzle path.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the above control, a large number of parameters in layered manufacturing are measured and controlled. Therefore, the control in the layered manufacturing apparatus becomes complicated.

[0006] An example of the problem to be solved by the present invention is to provide a layered manufacturing system capable of simplifying control.

Means for Solving the Problems

[0007] An additive manufacturing system according to one embodiment comprises a nozzle, a moving device, a measuring device, and a control device. The nozzle has a nozzle head and discharges powder from the tip of the nozzle head toward a convergence point, and irradiates the convergence point with an energy ray from the tip of the nozzle head to melt or sinter the powder, thereby forming a plurality of layers stacked in the stacking direction from the powder. The moving device moves the nozzle. The measuring device is attached to the nozzle at a position spaced apart from the tip of the nozzle head in a direction intersecting the stacking direction, and is movable integrally with the nozzle. The measuring device measures the distance in the stacking direction between the measuring device and one of the plurality of layers formed. The control device calculates the distance in the stacking direction between the tip of the nozzle head and one of the plurality of layers, based on the distance in the stacking direction between the measuring device and one of the plurality of layers formed, as measured by the measuring device. The control device repeatedly performs the following actions: forming one of the plurality of layers with the nozzle, and moving the nozzle by the moving device by a pitch in the stacking direction, until the nozzle has formed a predetermined number of layers. After the nozzle has formed a predetermined number of layers among the plurality of layers, and has moved by the pitch amount, The measuring device measures the distance between the measuring device and the specified number of layers formed from the plurality of layers, and based on the measured distance, a first distance is calculated between the tip of the nozzle head and the specified number of layers from the plurality of layers, and based on the measured first distance, the moving device moves the nozzle in the stacking direction so that the first distance approaches a second distance between the tip of the nozzle head and the convergence point. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is an illustrative perspective view illustrating a schematic additive manufacturing system according to one embodiment. [Figure 2] Figure 2 is an illustrative cross-sectional view schematically showing a part of the additive manufacturing system and an object according to the above embodiment. [Figure 3]Figure 3 is an illustrative block diagram that functionally shows the configuration of the additive manufacturing system of the above embodiment. [Figure 4] Figure 4 is a schematic cross-sectional view showing the nozzle head, the layer, and the multiple layers that the NC program is intended to form according to the above embodiment. [Figure 5] Figure 5 is a flowchart showing an example of additive manufacturing control for the additive manufacturing system in the above embodiment. [Modes for carrying out the invention]

[0009] An embodiment will be described below with reference to Figures 1 to 5. In this specification, the vertically upward direction is generally defined as the upward direction, and the vertically downward direction as the downward direction. Furthermore, in this specification, the components of an embodiment and their descriptions may be described using multiple expressions. The components and their descriptions are examples and are not limited by the expressions used in this specification. Components may also be identified by names different from those used in this specification. Furthermore, components may also be described using expressions different from those used in this specification.

[0010] Figure 1 is a schematic and exemplary perspective view of an additive manufacturing system 1 according to one embodiment. The additive manufacturing system 1 is a system that includes a so-called DED (Direct Energy Deposition) type three-dimensional printer. Note that the additive manufacturing system 1 is not limited to this example.

[0011] As shown in each drawing, the X, Y, and Z axes are defined herein for convenience. The X, Y, and Z axes are orthogonal to each other. The Z axis extends, for example, in the vertical direction. The X and Y axes extend, for example, in the horizontal direction. The additive manufacturing system 1 may be positioned such that the Z axis intersects the vertical direction at an angle.

[0012] Furthermore, the X, Y, and Z directions are defined herein. The X direction is the direction along the X axis and includes the +X direction indicated by the X-axis arrow and the -X direction which is the opposite direction of the X-axis arrow. The Y direction is the direction along the Y axis and includes the +Y direction indicated by the Y-axis arrow and the -Y direction which is the opposite direction of the Y-axis arrow. The Z direction is the direction along the Z axis and includes the +Z direction (up) indicated by the Z-axis arrow and the -Z direction (down) which is the opposite direction of the Z-axis arrow.

[0013] Figure 2 is a schematic cross-sectional view illustrating a part of the additive manufacturing system 1 and an object 3 according to this embodiment. The additive manufacturing system 1 additively manufactures (additive manufacturing) an object 3 of a predetermined shape by, for example, stacking powdered material M in layers. Material M is an example of a powder.

[0014] As shown in Figure 1, the additive manufacturing system 1 includes a table 11, an additive manufacturing device 12, a measuring device 13, a control device 14, and a plurality of signal lines 16. For example, the table 11, the additive manufacturing device 12, and the control device 14 are included in the 3D printer of the additive manufacturing system 1.

[0015] The table 11 has a support surface 11a. The support surface 11a is formed to be substantially flat and faces the +Z direction. The support surface 11a supports the additively manufactured object 3, the work-in-progress of object 3, and the base for stacking material M. In the following description, object 3 includes the completed additively manufactured object 3, the work-in-progress of object 3, and the base. By rotating the support surface 11a, the table 11 can rotate the object 3 supported by the support surface 11a around a center of rotation parallel to the Z axis.

[0016] Table 11 may move object 3 in the X-axis, Y-axis, and Z-axis directions. Table 11 may also rotate object 3 further around a rotation center parallel to the Y-axis or a rotation center parallel to the X-axis.

[0017] The additive manufacturing apparatus 12 supplies the material M shown in FIG. 2 and stacks it on the support surface 11a or on a base supported by the support surface 11a. The material M is, for example, a powdered metal. Note that the material M is not limited to this, and other materials such as synthetic resins and ceramics may be used. The additive manufacturing system 1 may perform additive manufacturing of the object 3 using a plurality of types of materials M.

[0018] The additive manufacturing apparatus 12 includes a nozzle 21, a supply device 22, and a moving device 23. As shown in FIG. 2, the nozzle 21 discharges the material M onto the support surface 11a of the table 11 or onto the object 3 on the support surface 11a. Further, the energy beam E is irradiated from the nozzle 21 onto the discharged material M and the object 3 on the support surface 11a. The energy beam E is, for example, laser light.

[0019] Laser light as the energy beam E is irradiated from the nozzle 21 in parallel with the supply of the material M. Other energy beams E may be irradiated from the nozzle 21, not limited to laser light. The energy beam E may be any one that can melt or sinter the material M, such as an electron beam or an electromagnetic wave in the microwave to ultraviolet region.

[0020] The additive manufacturing apparatus 12 heats the base and the discharged material M with the energy beam E to form a melting region 3a. The nozzle 21 irradiates the material M with the energy beam E in the melting region 3a to melt or sinter it and aggregate the material M. Thus, the melting region 3a may include not only the supplied material M but also a part of the base and the object 3 irradiated with the energy beam E. Further, the melting region 3a may be not only the completely melted material M but also a combination of partially melted materials M.

[0021] When the melting region 3a solidifies, a layer 3b as a collection of the material M in the form of a layer or a thin film is formed from the material M on the base or the object 3. In the present embodiment, the additive manufacturing apparatus 12 forms a bead-shaped layer 3b by moving the nozzle 21 while forming the layer 3b. The additive manufacturing apparatus 12 can form one film-shaped layer 3b extending in the X-Y direction by continuously arranging the bead-shaped layers 3b on the X-Y plane. Note that the material M may be granulated and laminated by being cooled by heat transfer to the collection of the material M, and may become a granulated collection (layer).

[0022] The additive manufacturing apparatus 12 may perform an annealing process by irradiating the collection of the material M with the energy beam E from the nozzle 21. The granulated collection of the material M may be remelted or sintered by the energy beam E and solidified to become the layer 3b.

[0023] The additive manufacturing apparatus 12 additive manufactures the object 3 by repeatedly laminating a plurality of layers 3b in the Z direction. The Z direction is an example of the lamination direction. Thus, the nozzle 21 irradiates the energy beam E to melt or sinter the material M, forms a plurality of layers 3b laminated in the Z direction, and repeatedly forms the layer 3b, thereby additive manufacturing the object 3 supported on the support surface 11a.

[0024] The nozzle 21 has a nozzle head 31. The tip 31a of the nozzle head 31 faces the object 3 with an interval therebetween. An emission path 32, a discharge path 33, and a supply path 34 are provided in the nozzle head 31. The emission path 32, the discharge path 33, and the supply path 34 open, for example, at the tip 31a.

[0025] The ejection channel 32 is a hole with a substantially circular cross-section. Energy rays E are ejected through the ejection channel 32 to the outside of the nozzle head 31. The discharge channel 33 is a hole with a substantially annular cross-section and is provided so as to surround the ejection channel 32. Carrier gas and material M are discharged through the discharge channel 33 to the outside of the nozzle head 31. The supply channel 34 is a hole with a substantially annular cross-section and is provided so as to surround the discharge channel 33. Shielding gas G is discharged through the supply channel 34 to the outside of the nozzle head 31. The shielding gas G may also be discharged from the ejection channel 32. The shielding gas G is, for example, an inert gas such as nitrogen or argon.

[0026] The nozzle 21 discharges the material M in a roughly conical shape toward the convergence point PC. Therefore, the material M discharged from the nozzle 21 converges at the convergence point PC. Furthermore, the nozzle 21 irradiates the convergence point PC with an energy ray E. In other words, the focal point of the energy ray E is set at or near the convergence point PC. Note that the focal point of the energy ray E may be set at a position different from the convergence point PC. In this case, the energy ray E irradiates the material M that converges at the convergence point PC over a wider area.

[0027] As shown in Figure 1, the supply device 22 includes an optical device 41, a material supply device 42, and a gas supply device 43. The optical device 41 includes, for example, a light source and an optical system. The light source has an oscillating element, and emits laser light as an energy ray E by oscillation of the oscillating element.

[0028] The light source causes the emitted energy ray E to enter the optical system. The energy ray E enters the nozzle 21 via the optical system. The optical device 41 supplies the energy ray E to the exit path 32 of the nozzle 21 and causes the energy ray E to be emitted from the exit path 32. Part of the optical system is provided, for example, inside the nozzle 21 to focus the energy ray E.

[0029] The nozzle 21 can heat the discharged material M by irradiation with energy rays E, thereby forming a layer 3b of the material M and performing annealing. The nozzle 21 may also remove unwanted parts of the object 3 by irradiation with energy rays E.

[0030] The material supply device 42 includes a material supply unit 42a and a tank 42b. The tank 42b contains material M. The material supply device 42 may have multiple tanks 42b, each containing different types of material M.

[0031] The material supply unit 42a supplies material M from tank 42b to nozzle 21 via supply pipe 21a. The material supply unit 42a supplies material M to nozzle 21 using, for example, a carrier gas. The carrier gas is an inert gas such as nitrogen or argon. As a result, nozzle 21 discharges the carrier gas and material M from discharge passage 33.

[0032] The material supply unit 42a includes, for example, a tank for containing carrier gas, a compressor for flowing the carrier gas from the tank to the supply pipe 21a, and a device for supplying material M from tank 42b to the flow of carrier gas. The material supply unit 42a may also supply material M to the nozzle 21 by other means.

[0033] The gas supply device 43 includes a gas supply unit 43a and a tank 43b. The tank 43b contains shielding gas G. The gas supply unit 43a supplies the shielding gas G from the tank 43b to the nozzle 21 via a supply pipe 21a. The supply pipe 21a includes a pipe through which the carrier gas and material M pass, a pipe through which the shielding gas G passes, and a cable through which the energy rays E pass.

[0034] The moving device 23 moves and rotates the nozzle 21. For example, the moving device 23 can move the nozzle 21 in the X, Y, and Z directions, as well as rotate it around a rotation center parallel to the Y axis.

[0035] The moving device 23 can move the nozzle 21 relative to the support surface 11a, thereby changing the orientation of the nozzle 21. Alternatively, the movement and rotation of the table 11 may also cause the nozzle 21 to move relative to the support surface 11a, thereby changing the orientation of the nozzle 21 relative to the support surface 11a.

[0036] In this embodiment, the moving device 23 includes a first moving part 51, a second moving part 52, a third moving part 53, and a rotating part 54. The first moving part 51, the second moving part 52, the third moving part 53, and the rotating part 54 may also be referred to as drive shafts.

[0037] The first movable part 51 moves in the Y direction relative to the table 11. The second movable part 52 is attached to the first movable part 51 so as to be movable in the Z direction. The third movable part 53 is attached to the second movable part 52 so as to be movable in the X direction. The rotating part 54 is attached to the third movable part 53 so as to be rotatable about a rotation center extending in the Y direction.

[0038] The nozzle 21 is attached to the rotating part 54. As a result, the first moving part 51 moves the nozzle 21 in the Y direction, the second moving part 52 moves the nozzle 21 in the Z direction, the third moving part 53 moves the nozzle 21 in the X direction, and the rotating part 54 rotates the nozzle 21 around its central axis. Note that the moving device 23 is not limited to this example and may be, for example, a multi-jointed robot arm.

[0039] The measuring device 13 is a device capable of measuring the distance between the measuring device 13 and the object to be measured. For example, the measuring device 13 is, for example, a laser rangefinder. However, the measuring device 13 is not limited to this example and may be, for example, a camera, another non-contact type position measuring device, or a contact type position measuring device.

[0040] The measuring device 13 is attached to the nozzle 21, for example. This allows the measuring device 13 to move integrally with the nozzle 21. However, the measuring device 13 is not limited to this example; for example, it may be movable independently of the nozzle 21, or it may be fixed to the chamber housing the additive manufacturing apparatus 12.

[0041] The measuring device 13 is spaced apart from the tip 31a of the nozzle head 31 in at least one of the X and Y directions. This minimizes the influence of energy rays E, heat from the molten region 3a, and fumes scattered from the molten region 3a on the measuring device 13.

[0042] The control device 14 is electrically connected to the table 11, the additive manufacturing apparatus 12, and the measuring device 13 via signal lines 16. The control device 14 may be, for example, a control unit integrated with the additive manufacturing apparatus 12, or a computer provided separately from the additive manufacturing apparatus 12.

[0043] The control device 14 has a hardware configuration that utilizes a typical computer, including, for example, a control device such as a CPU (Central Processing Unit) 14a, a ROM (Read Only Memory) 14b, a RAM (Random Access Memory) 14c, an external storage device 14d, an output device 14e, and an input device 14f. The CPU 14a, ROM 14b, RAM 14c, external storage device 14d, output device 14e, and input device 14f are connected to each other by a bus or via an interface.

[0044] The CPU 14a executes a program stored in the ROM 14b or external storage device 14d, thereby controlling each part of the additive manufacturing system 1. For example, the control device 14 controls the table 11 and the nozzle 21, moving device 23, optical device 41, material supply device 42, and gas supply device 43 of the additive manufacturing apparatus 12.

[0045] ROM 14b stores the program and the data necessary for program execution. RAM 14c functions as a workspace during program execution. External storage device 14d is a device capable of storing, modifying, and deleting data, such as an HDD (Hard Disk Drive) or SSD (Solid State Drive). Output device 14e is, for example, a display or speaker. Input device 14f is, for example, a keyboard, mouse, and an interface that receives data via communication.

[0046] Figure 3 is an exemplary block diagram illustrating the functional configuration of the additive manufacturing system 1 of this embodiment. The control device 14 realizes the various parts shown in Figure 3 by, for example, the CPU 14a reading and executing a program stored in the ROM 14b or external storage device 14d. As shown in Figure 3, the control device 14 includes, for example, a storage unit 61, a manufacturing control unit 62, a measurement control unit 63, a correction value calculation unit 64, and a correction execution unit 65.

[0047] For example, the CPU 14a functions as a molding control unit 62, a measurement control unit 63, a correction value calculation unit 64, and a correction execution unit 65. In addition, the RAM 14c and external storage device 14d function as a storage unit 61.

[0048] The memory unit 61 stores various information, including an NC program 71 and log data 72. The NC program 71 is information for additive manufacturing of multiple layers 3b and an object 3 containing those layers 3b.

[0049] The NC program 71 includes, for example, information relating to the movement path (coordinates) and velocity of the nozzle 21 for forming each layer 3b, the start and stop of material M discharge, and the start and stop of energy ray E emission.

[0050] For example, the NC program 71 moves the nozzle 21 to the coordinates in the Z direction corresponding to a layer 3b in order to form that layer 3b. Furthermore, the NC program 71 moves the nozzle 21, which ejects material M and emits energy rays E, along a set of coordinates (path) in the X and Y directions corresponding to that layer 3b. Thus, the NC program 71 has coordinates in the Z direction and a set of coordinates (path) in the X and Y directions corresponding to each layer 3b.

[0051] Figure 4 is a schematic cross-sectional view showing the nozzle head 31, layer 3b, and multiple layers 3b (3bp) that the NC program 71 is intended to form. Hereinafter, the layers 3b that the NC program 71 is intended to form will be referred to as layer 3bp. On the other hand, the layers 3b that are actually formed will be referred to as layer 3b.

[0052] As shown in Figure 4, the NC program 71 is a program that causes the additive manufacturing apparatus 12 to form multiple layers 3bp, indicated by the dashed lines. The sum of the thicknesses of the multiple layers 3bp in the Z direction is equal to the length (height) of the model of object 3 in the Z direction in the NC program 71, or the CAD data, CAM data, or CAD / CAM data on which the NC program 71 is based.

[0053] The thickness of layer 3bp in the Z direction is equal to the distance (pitch PL) that the NC program 71 moves the nozzle 21 in the Z direction between the formation of one layer 3b and the formation of another layer 3b. In other words, the NC program 71 is a program for forming multiple layers 3b on the nozzle 21 at predetermined intervals (pitch PL) in the Z direction.

[0054] In this embodiment, the pitch PL is set to be approximately the same as the thickness T in the Z direction of the layer 3b actually formed by the additive manufacturing apparatus 12. The thickness T can be obtained, for example, by measuring the layer 3b formed by the additive manufacturing apparatus 12 or by simulation. However, the thickness T is not necessarily exactly the same as the pitch PL. For example, when the pitch PL is set to 1 mm, an error of several μm may occur between the thickness T and the pitch PL.

[0055] As shown in Figure 3, the molding control unit 62 controls the additive manufacturing apparatus 12, which includes a moving device 23, an optical device 41, a material supply device 42, and a gas supply device 43, based on the NC program 71, to additively manufacture multiple layers 3b (objects 3).

[0056] The measurement control unit 63 controls the measuring device 13 and measures the distance between the measuring device 13 and a desired position on the surface of the object 3. Furthermore, the measurement control unit 63 calculates the distance between the nozzle 21 and the object 3 based on the distance between the measuring device 13 and the object 3.

[0057] As described above, the measuring device 13 is movable integrally with the nozzle 21. Therefore, the measurement control unit 63 can easily calculate the distance between the nozzle 21 and the object 3 from the distance between the measuring device 13 and the object 3.

[0058] In this embodiment, the measurement control unit 63 controls the measuring device 13 to measure the distance in the Z direction between the nozzle 21 and at least one of the multiple layers 3b that has been formed up to the time of measurement. Specifically, the measurement control unit 63 causes the measuring device 13 to measure the distance in the Z direction between the tip 31a of the nozzle head 31 and the upper surface 3c of the layer 3b. The upper surface 3c is the end face of the layer 3b in the +Z direction. The measuring device 13 and the measurement control unit 63 function as an example of a measuring device. Note that the measuring device 13 may also be an example of a measuring device on its own.

[0059] The measurement control unit 63 receives, for example, the output signal of the measuring device 13 amplified by the amplifier 13a. Based on the output signal of the measuring device 13, the measurement control unit 63 obtains the distance in the Z direction between the nozzle 21 and at least one of the multiple layers 3b that has been formed up to the time of measurement.

[0060] The correction value calculation unit 64 calculates a correction value to correct the Z-axis coordinate of the nozzle 21 based on the distance between the nozzle 21 and the layer 3b measured by the measurement control unit 63. The correction execution unit 65 corrects the Z-axis coordinate of the nozzle 21 using the correction value calculated by the correction value calculation unit 64.

[0061] Figure 5 is a flowchart showing an example of additive manufacturing control for the additive manufacturing system 1 in this embodiment. The additive manufacturing of object 3 by the additive manufacturing system 1 of this embodiment will be described in detail below. Note that the additive manufacturing by the additive manufacturing system 1 is not limited to the example described below.

[0062] First, the molding control unit 62 reads the NC program 71 from the storage unit 61 (S101). Next, the output value of the measuring device 13 is initialized (S102). For example, the molding control unit 62 controls the moving device 23 to move the nozzle 21 to a coordinate in the Z direction for forming the first layer 3b. At that coordinate, the measurement control unit 63 controls the measuring device 13 to measure the distance in the Z direction between the nozzle 21 and the base. The measurement control unit 63 sets the output value of the measuring device 13 for this measurement to "0".

[0063] During initialization, the distance between the tip 31a of the nozzle head 31 and the base is set to the working distance WD shown in Figure 2. The working distance WD is the distance between the tip 31a of the nozzle head 31 and the convergence point PC in the Z direction.

[0064] The working distance WD is a value specific to the additive manufacturing apparatus 12. For example, the working distance WD is set by the shape of the discharge path 33 of the nozzle head 31 and the speed at which the material supply device 42 discharges the material M. The working distance WD may also be adjustable.

[0065] The additive manufacturing apparatus 12 is generally configured such that a desired amount of material M is supplied to the convergence point PC, the irradiation diameter of the energy ray E at the convergence point PC is of a desired size, and a desired amount of heat is input from the energy ray E to the material M at the convergence point PC. When the distance between the nozzle 21 and the position (processing point) where the molten region 3a is formed on the surface of the base or layer 3b is equal to the working distance WD, the additive manufacturing apparatus 12 can form a layer 3b under the desired conditions.

[0066] As shown in Figure 5, the molding control unit 62 then forms a layer 3b based on the NC program 71 (S103). For example, the molding control unit 62 moves the nozzle 21, which ejects material M and emits energy rays E at the same position in the Z direction, in the X and Y directions. As a result, a layer 3b is formed that spreads on the XY plane at a desired coordinate in the Z direction.

[0067] Next, the molding control unit 62 determines whether all layers 3b have been formed (S104). For example, the molding control unit 62 determines whether the entire NC program 71 has been executed. If not all layers 3b have been formed (S104: No), the molding control unit 62 moves the nozzle 21 to the Z coordinate for forming the next layer 3b in the NC program 71 (S105). For example, the molding control unit 62 controls the moving device 23 to move the nozzle 21 by a pitch PL in the +Z direction.

[0068] Next, the measurement control unit 63 determines whether a specified number of layers 3b have been formed (S106). The specified number is a positive integer and can be arbitrarily set based on, for example, an input signal from the input device 14f. For example, the specified number is "1". The specified number may also be greater than "1". In this embodiment, the specified number specifies how often the measurement is performed after each additive manufacturing cycle. That is, if the specified number is set to "N", the following measurement is performed once every N additive manufacturing cycles.

[0069] If the specified number of layers 3b have not been formed (S106: No), the process returns to S103, and the molding control unit 62 forms the next layer 3b. Steps S103 to S106 are repeated until the specified number of layers 3b have been formed.

[0070] If a specified number of layers 3b have been formed in S106 (S106: Yes), the measurement control unit 63 controls the measurement device 13 to measure the distance in the Z direction between the nozzle 21 and at least one of the multiple layers 3b that have been formed up to the time of measurement (S107).

[0071] In this embodiment, the molding control unit 62 stops the ejection of material M and the emission of energy rays E from the nozzle 21, and moves the nozzle 21 in the X and Y directions. As a result, the measuring device 13 moves integrally with the nozzle 21 and continuously outputs the distance between multiple points on the layer 3b and the measuring device 13 as multiple output values.

[0072] The measurement control unit 63 controls the measurement device 13 to continuously measure, for example, the distance between the nozzle 21 and one bead in layer 3b. The measurement device 13 is not limited to this example; it may also continuously measure the distance between the nozzle 21 and multiple beads in layer 3b, or it may continuously measure the distance between the nozzle 21 and the entire upper surface 3c of layer 3b.

[0073] When the thickness T of the formed layer 3b is equal to the pitch PL of layer 3b in the NC program 71, the distance between the nozzle 21 and layer 3b becomes equal to the working distance WD. In this case, the output value of the measuring device 13 becomes "0".

[0074] The thickness T of the formed layer 3b may differ from the pitch PL of layer 3b in the NC program 71. For example, if the thickness T is shorter than the pitch PL, the distance between the nozzle 21 and layer 3b will be longer than the working distance WD. In this case, the output value of the measuring device 13 will be greater than, for example, "0". Also, for example, if the thickness T is longer than the pitch PL, the distance between the nozzle 21 and layer 3b will be shorter than the working distance WD. In this case, the output value of the measuring device 13 will be less than, for example, "0".

[0075] Next, the correction value calculation unit 64 calculates the correction value (S108). In this embodiment, the correction value calculation unit 64 obtains from the measurement control unit 63 multiple output values ​​continuously output by the measuring device 13 during the measurement of one layer 3b. The correction value calculation unit 64 calculates the average value of the multiple output values ​​of the measuring device 13, reverses the sign of the average value, and calculates the correction value. For example, if the average value of the output values ​​of the measuring device 13 is "+Za", the correction value calculation unit 64 calculates the correction value "-Za". In this way, the correction value calculation unit 64 calculates the correction value from the measured distance between the nozzle 21 and the layer 3b.

[0076] The correction value calculation unit 64 is not limited to the above example. For example, instead of calculating the average value from the multiple output values ​​of the measuring device 13, the correction value calculation unit 64 may calculate the median, minimum, or maximum value.

[0077] Next, the correction value calculation unit 64 saves the calculated correction value as log data 72 in the storage unit 61 (S109). For example, the operator of the additive manufacturing system 1 can refer to the history of the deviation between the distance between the nozzle 21 and the layer 3b and the working distance WD from the log data 72.

[0078] Next, the correction execution unit 65 corrects the position of the nozzle 21 (S110). For example, in the incremental method, the correction execution unit 65 executes a movement instruction as an interrupt process, setting the correction value to an increment value. As a result, the molding control unit 62 controls the moving device 23 based on the movement instruction and moves the nozzle 21. For example, the moving device 23 moves the nozzle 21 by a distance "Za" in the -Z direction based on the correction value "-Za".

[0079] On the other hand, in the absolute method, the correction execution unit 65 calculates a corrected coordinate by adding a correction value to the current coordinate of the nozzle 21 in the Z direction. The correction execution unit 65 executes a movement instruction specifying the corrected coordinate as an interrupt process. As a result, the molding control unit 62 controls the moving device 23 based on the movement instruction and moves the nozzle 21 to the corrected coordinate. Alternatively, for example, the correction execution unit 65 may add a correction value to subsequent coordinates in the Z direction in the NC program 71.

[0080] As described above, when the correction execution unit 65 executes the movement instruction as an interrupt process, the molding control unit 62 moves the nozzle 21 to the moving device 23 in the Z direction based on the correction value calculated from the measured distance. As a result, the distance between the nozzle 21 and the layer 3b approaches the working distance WD.

[0081] Next, returning to S103, the molding control unit 62 forms the next layer 3b. Since the distance between the nozzle 21 and the layer 3b is set to approximately the working distance WD, the additive manufacturing apparatus 12 can form the layer 3b under the desired conditions.

[0082] Steps S103 to S110 are repeated until it is determined in S104 that all layers have been formed. If all layers 3b have been formed in S104 (S104: Yes), the molding control unit 62 terminates the additive manufacturing. As a result, multiple layers 3b are stacked in the Z direction, and the additive manufacturing of object 3 is completed.

[0083] In the additive manufacturing control of this embodiment described above, the distance between the nozzle 21 and the layer 3b is automatically corrected without interrupting the execution of the NC program 71. As a result, the additive manufacturing system 1 can maintain the distance between the nozzle 21 and the layer 3b at an appropriate working distance WD until the end of additive manufacturing, thereby forming multiple layers 3b.

[0084] In the additive manufacturing control of this embodiment described above, steps S107 to S110 are executed after one layer 3b has been formed. However, additive manufacturing control is not limited to this example. For example, additive manufacturing control may be performed when a part of layer 3b, such as a bead, is formed, or when an instruction is input to the input device 14f, steps S107 to S110 may be executed. Alternatively, additive manufacturing control may be performed before the nozzle 21 moves in step S105, steps S107 to S110 may be executed. In this case, the molding control unit 62 controls, for example, the moving device 23 to move the nozzle 21 to the corrected coordinates calculated by the correction execution unit 65.

[0085] In the additive manufacturing control of this embodiment described above, S102 to S110 are executed based on the NC program 71. However, for example, S102, S106 to S110 may be executed as interrupt processing for the NC program 71 based on a program different from the NC program 71.

[0086] In the additive manufacturing system 1 according to the embodiment described above, the additive manufacturing system 1 forms a plurality of layers 3b based on, for example, an NC program 71. However, the thickness T of each layer 3b actually formed by the additive manufacturing system 1 may differ from the spacing (pitch PL) of the layers 3b set in the NC program 71. The difference between the actual thickness T of the layers 3b and the pitch PL in the NC program 71 can cause, for example, the convergence point PC of the material M extruded by the nozzle 21 to be shifted from the surface of the layer 3b, or the irradiation diameter of the energy rays E on the surface of the layer 3b to be different from the desired size. For this reason, the above difference may make additive manufacturing by the additive manufacturing system 1 unstable and may degrade the quality of the additively manufactured object 3. In contrast, in the additive manufacturing system 1 of this embodiment, the measuring device 13 measures the distance between the nozzle 21 and one of the formed layers 3b. Based on the measured distance, the control device 14 moves the nozzle 21 in the Z direction using the moving device 23. As a result, the distance between the nozzle 21 and layer 3b is adjusted according to the actual additive manufacturing process performed by the additive manufacturing system 1. Therefore, the additive manufacturing system 1 of this embodiment can stably additively manufacture an object 3, and the shape of the object 3 that is actually additively manufactured can be brought closer to the shape of the object 3 model in the NC program 71. Furthermore, in this embodiment, there is no need to measure and adjust various conditions such as the output and irradiation diameter of the energy ray E, the movement speed and movement path of the nozzle 21, the type and supply amount of material M, the state of the gas surrounding layer 3b, and the temperature and shape of layer 3b. For this reason, the additive manufacturing system 1 of this embodiment simplifies the control in the additive manufacturing system 1 and can suppress increases in time and cost for additive manufacturing, for example.

[0087] The measuring device 13 is movable integrally with the nozzle 21. This stabilizes the relationship between the distance between the measuring device 13 and the layer 3b, and the distance between the nozzle 21 and the layer 3b. Therefore, for example, there is no need to reposition the measuring device 13 or correct the numerical values ​​for each measurement, and the measurement of the distance between the nozzle 21 and the layer 3b by the measuring device 13 becomes easy.

[0088] When the nozzle 21 forms a specified number of layers 3b, the measuring device 13 measures the distance between the nozzle 21 and the layers 3b, and the moving device 23 moves the nozzle 21 based on the measured distance. By setting the specified number, the distance between the nozzle 21 and the layers 3b is adjusted at the desired timing and frequency. For example, the smaller the specified number, the more the distance between the nozzle 21 and the layers 3b is maintained appropriately, and the larger the specified number, the more the increase in measurement time is suppressed. By appropriately setting the specified number, additive manufacturing becomes possible that satisfies the desired layering accuracy without increasing the layering time unnecessarily.

[0089] The control device 14 calculates a correction value from the measured distance. Based on this correction value, the control device 14 moves the nozzle 21 to the moving device 23. For example, the correction value is calculated as various calculated values ​​such as the average, median, minimum, or maximum value of the measured distance. This adjusts the distance between the nozzle 21 and the layer 3b to the desired degree.

[0090] In the above embodiment, the measuring device 13 and the measuring control unit 63 measure the distance between the nozzle 21 and layer 3b based on the distance between the measuring device 13 and layer 3b. However, the measuring device is not limited to this example. For example, the measuring device may measure the coordinates of the nozzle 21, measure the coordinates of layer 3b, and then measure the distance between the nozzle 21 and layer 3b from the coordinates of the nozzle 21 and layer 3b.

[0091] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of symbols]

[0092] 1...Additive manufacturing system, 3b...Layer, 13...Measurement device, 14...Control device, 21...Nozzle, 23...Moving device, 63...Measurement control unit, M...Material, E...Energy ray.

Claims

1. A nozzle having a nozzle head, which discharges powder from the tip of the nozzle head toward a convergence point, and irradiates the convergence point with an energy ray from the tip of the nozzle head to melt or sinter the powder, thereby forming multiple layers stacked in the stacking direction from the powder, A moving device for moving the nozzle, A measuring device is attached to the nozzle at a position spaced apart from the tip of the nozzle head in a direction intersecting the stacking direction, and is movable integrally with the nozzle. Control device and It is equipped with, The measuring device measures the distance in the stacking direction between the measuring device and one of the plurality of layers formed thereon. The control device calculates the distance between the tip of the nozzle head and the one of the multiple layers in the stacking direction based on the distance in the stacking direction between the measuring device and one of the multiple layers, as measured by the measuring device. The control device repeatedly performs the following actions: forming one of the plurality of layers with the nozzle, and moving the nozzle by the moving device by the pitch in the stacking direction, until the nozzle has formed a predetermined number of layers. After the nozzle has formed a predetermined number of layers among the plurality of layers, and has moved by the pitch amount, The measuring device is made to measure the distance between the measuring device and the specified number of layers formed among the plurality of layers, and a first distance is calculated between the tip of the nozzle head and the specified number of layers among the plurality of layers based on the measured distance. Based on the calculated first distance, the moving device moves the nozzle in the stacking direction so that the first distance approaches the second distance between the tip of the nozzle head and the convergence point. Additive manufacturing system.

2. The second distance is an intrinsic value in the additive manufacturing system. The additive manufacturing system according to claim 1.

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