DEVICE FOR ADDITIVE MANUFACTURING AND METHOD FOR ADDITIVE MANUFACTURING

Abstract

Additive manufacturing device (100) for forming an object (4) by repeated additive processing by melting a processing material (7) which is a wire and applying the molten processing material (7) to a workpiece (3), the additive manufacturing device comprising: a drive platform (6) which changes a positional relationship between the workpiece (3) and a processing head (2) which performs the additive processing and which stops at a plurality of processing points; a processing material feed unit (10) for feeding processing material (7) to the processing point; a processing laser (1) which is a light source which emits processing light (30) which melts the processing material (7) and stacks spherical beads from the molten and solidified processing material (7), the object (4) being formed by the solidified beads;a height measuring unit that measures the height of the object (4) formed at the processing point each time the drive platform (6) stops at one of the processing points; a measuring illumination unit (8) for projecting an illumination light (40) for height measurement parallel to the optical axis of the processing light (30); a light receiving unit (17) arranged at an oblique angle relative to the optical axis of the processing light (30) to receive the reflected light of the illumination light (40); and a control unit (51) that controls a processing condition for applying the processing material (7) at the processing point based on a measurement result provided by the height measuring unit.

Description

Area

[0001] The present invention relates to an additive manufacturing device, an additive manufacturing method and an additive manufacturing program for forming an object by applying machining material to a workpiece. background

[0002] Traditionally, known additive manufacturing devices such as three-dimensional printers (3D printers) use a technique known as additive manufacturing (AM), in which a three-dimensional object is formed by stacking layers of processing material on top of each other.

[0003] Patent reference 1 discloses an additive manufacturing device that uses directed energy deposition (DED) as a method for stacking layers of metallic processing material. The additive manufacturing device described in patent reference 1, which uses directed energy deposition, feeds a metallic processing material, such as a metal wire or metal powder, from a feed port to a processing position, melting and depositing the processing material with a laser, an electron beam, or the like to form an object with a desired shape. An electric current is applied to the wire representing the processing material, causing a molten droplet to form at the end of the wire. The molten droplet is then deposited in a melt pool formed on the workpiece, thereby forming the object.This additive manufacturing device controls the supply of electricity to the wire to melt the wire and to detach the droplets from the wire. List of cited documents Patent literature

[0004] Patent literature 1: Japanese patent application publication no. 2016-179501 Brief description of the technical problem

[0005] In the additive manufacturing device described in patent literature 1, the workpiece can be destroyed if an arc discharge occurs between the wire and the workpiece. Therefore, it is necessary to precisely control the current supply to the wire to prevent an arc discharge. However, depending on the processing conditions, controlling the current supply to the wire to prevent an arc discharge can lead to insufficient detachment of the droplets from the wire. This results in the problem that the produced beads do not have a uniform height, leading to a deterioration in the shape accuracy of the object.

[0006] The present invention was developed in light of the above considerations, one of its objectives being to create an additive manufacturing device capable of improving the dimensional accuracy of an object. Solution to the problem

[0007] To solve the problem described above and to fulfill the objective, the present invention provides an additive manufacturing device for forming an object by repeated additive processing through melting a processing material and applying the solidified processing material to a workpiece, wherein the additive manufacturing device comprises: a height measuring unit for measuring a height of the object formed at a processing position; and a control unit for controlling a processing condition for applying the processing material at the processing position based on a measurement result provided by the height measuring unit. Advantageous effects of the invention

[0008] The present invention makes it possible to obtain an additive manufacturing device that is capable of improving the dimensional accuracy of an object. List of characters Fig. Figure 1 is a diagram showing a configuration of an additive manufacturing device according to a first embodiment of the present invention. Fig. Figure 2 is a diagram showing dedicated hardware for implementing the functions of the computing unit and the control unit, which are described in Fig. 1 are shown. Fig. Figure 3 is a diagram showing a configuration of a control circuit for implementing the functions of the computing unit and the control unit, which are described in Fig. 1 are shown. Fig. 4 is a diagram showing the internal configuration of the Fig. 1 shows the machining head. Fig. 5 is a flowchart to illustrate a process in which the in Fig. 1 The device shown for additive manufacturing forms a spherical bead. Fig. 6 is a schematic cross-sectional diagram showing the processing area of ​​the Fig. Figure 1 shows the device for additive manufacturing. Fig. 7 is a schematic cross-sectional diagram in which the wire leading to the processing area of ​​the in Fig. The device shown in 1 for additive manufacturing is output and is in contact with the additive target surface. Fig. Figure 8 is a schematic cross-sectional diagram showing the processing area of ​​the Fig. The device shown in Figure 1 for additive manufacturing is irradiated with processing light. Fig. 9 is a schematic cross-sectional diagram showing the wire feed to the processing area of ​​the Fig. The device shown in 1 for additive manufacturing was started. Fig. 10 is a schematic cross-sectional diagram in which the wire from the processing area of ​​the in Fig. The device shown in 1 is used for additive manufacturing. Fig. 11 is a schematic cross-sectional diagram showing the irradiation of the processing area of ​​the in Fig. The device shown in Figure 1 for additive manufacturing was stopped using processing light. Fig. 12 is a schematic cross-sectional diagram in which the processing head of the in Fig. The device shown in section 1 for additive manufacturing is moved to the next processing point. Fig. Figure 13 is a schematic cross-sectional diagram illustrating a method for producing an object with the in Fig. 1 device for additive manufacturing shown. Fig. 14 is a diagram showing the height of the wire relative to the object passing through it. Fig. 1. Device for additive manufacturing is formed as shown. Fig. 15 is a diagram that schematically shows an XZ cross-section of the object, as seen from the in Fig. The illumination light is projected onto the measuring illumination unit shown in section 1. Fig. Figure 16 is a diagram showing the light-receiving position on the light-receiving element, with the object defined by the in Fig. 1 The device shown for additive manufacturing is illuminated with illumination light. Fig. Figure 17 is a flowchart illustrating a process for carrying out an additive process using the result of measuring the height of the object, which is measured by the in Fig. 1. Device for additive manufacturing is formed as shown. Fig. Figure 18 is a diagram showing a method for controlling the wire feed rate when the in Fig. 1. The device shown for additive manufacturing processes the second layer. Fig. 19 is a diagram showing an example where the processing condition, which is in Fig. 1. The device shown for additive manufacturing controls the number of spherical beads. Fig. 20 is a diagram showing a procedure in which the in Fig. 1. The device shown for additive manufacturing controls the wire height based on the result of the measurement of the object's height. Fig. 21 is a diagram showing a modification of the shape of a pearl, which is caused by the in Fig. 1. Device for additive manufacturing was formed as shown. Fig. 22 is a diagram showing a modification of the measuring position for measuring the height of the object passing through the Fig. 1. Device for additive manufacturing was formed as shown. Fig. Figure 23 is a diagram illustrating the problem that is to be solved by an additive manufacturing device according to a second embodiment of the present invention. Fig. Figure 24 is a flowchart to illustrate the machining position search process of the device for additive manufacturing according to the second embodiment of the present invention. Fig. Figure 25 is a diagram showing the positional relationship between the measuring illumination unit and a bead before the start of the process. Fig. 24 shows. Fig. 26 is a diagram showing the light-receiving position on the light-receiving element in the Fig. The depicted state is shown in section 25. Fig. 27 is a diagram showing the positional relationship between the measuring illumination unit and the workpiece after step S301 of Fig. 24 shows. Fig. 28 is a diagram showing the light-receiving position on the light-receiving element in the Fig. The depicted state is shown in 27. Fig. 29 is a diagram showing the positional relationship between the measuring illumination unit and the workpiece after step S302 of Fig. 24 shows. Fig. 30 is a diagram showing the light-receiving position on the light-receiving element in the Fig. The condition shown in 29 is depicted. Fig. 31 is a diagram showing a predetermined area that is defined in step S303 of Fig. 24 is used. Fig. 32 is a diagram showing the drive platform in step S304 of Fig. It was stopped at 24. Fig. 33 is a diagram for comparing the state before the process of Fig. 24 and the state after step S304. Fig. Figure 34 is a diagram showing a configuration of an additive manufacturing device according to a third embodiment of the present invention. Fig. 35 is a diagram that shows the internal configuration of the Fig. 34 shows the machining head. Fig. 36 is a diagram to explain the measurement of altitude in the Fig. Device for additive manufacturing shown in 34. Fig. 37 is a diagram showing the light reception position of the light emitted from the Fig. 36(a) is reflected in the pearl shown. Fig. 38 is a diagram showing the light reception position of the light emitted from the Fig. 36(b) is reflected in the pearl shown. Fig. 39 is a diagram showing the light reception position of the light emitted from the Fig. 36(c) is reflected in the pearl shown. Fig. 40 is a diagram that is a modification of the in Fig. Figure 35 shows the device for additive manufacturing. Description of embodiments

[0009] The following describes in detail an additive manufacturing device, an additive manufacturing method, and an additive manufacturing program according to embodiments of the present invention with reference to the drawings. The present invention is not limited to these embodiments. First embodiment.

[0010] Fig. Figure 1 is a diagram showing a configuration of an additive manufacturing device 100 according to the first embodiment of the present invention. The additive manufacturing device 100 is described below as a metal additive manufacturing device that uses metal as the processing material; however, it can also be an additive manufacturing device that uses a processing material other than metal, such as resin. In the following description, an object formed by the additive manufacturing device 100 can also be referred to as a deposit. The additive manufacturing device 100 performs additive manufacturing by melting the processing material using a processing laser and depositing the processing material onto the surface of a target, i.e., a workpiece. However, the additive manufacturing device 100 can also employ a different processing method, such as...Use arc discharge.

[0011] The device for additive manufacturing 100 includes a processing laser 1, a processing head 2, a holder 5 for attaching a workpiece 3, a drive platform 6, a measuring illumination unit 8, a gas nozzle 9, a processing material feed unit 10, a calculation unit 50 and a control unit 51.

[0012] The additive manufacturing device 100 repeats the additive manufacturing process by melting a processing material 7 and applying the molten material to the workpiece 3, thereby forming an object 4. The additive manufacturing device 100 has a function of measuring the height of the object 4 formed in this way and controlling the processing conditions for the next additive manufacturing process based on the measurement result. The configuration of the additive manufacturing device 100 for performing this function is described below.

[0013] The processing laser 1 is a light source that emits processing light 30 for use in forming operations, i.e., in creating the object 4 on the workpiece 3. The processing laser 1 is a fiber laser device that uses a semiconductor laser, a CO2 laser device, or the like. The wavelength of the processing light 30 emitted by the processing laser 1 is, for example, 1070 nm.

[0014] The processing head 2 includes a processing optics system and a light-receiving optics system. The processing optics system concentrates the processing light 30 emitted by the processing laser 1 and focuses it onto a processing position on the workpiece 3. The light-receiving optics system is also referred to as a height sensor. Generally, the processing light 30 is concentrated into a point at the processing position, and therefore the processing position is referred to as the processing point. The processing laser 1 and the processing optics system define a processing unit. The method for measuring the height of the object 4 formed at the processing position is described below as a line-intersection method that uses an optical system. However, the method for measuring the height of the object 4 can also be, for example,It should be an optical method that differs from the line-separation method. The optical method is, for example, a point-type triangulation method or a confocal method.

[0015] The light-receiving optical system is located within the processing head 2, and the processing optical system and the light-receiving optical system are integrated together. This results in a reduction in the size of the additive manufacturing device 100. However, the present embodiment is not limited to this example. There are no restrictions regarding the type of integration of the processing head 2 and the height sensor.

[0016] The workpiece 3 is also referred to as the "work". The workpiece 3 is placed on the drive platform 6 and secured to the drive platform 6 with the holder 5. The workpiece 3 serves as the base on which the object 4 is formed, with the surface of the workpiece 3 also being referred to as the surface to be machined. Here, the workpiece 3 is a base plate, but it can also be an object with a three-dimensional shape.

[0017] When the drive platform 6 is driven, the position of the workpiece 3 relative to the machining head 2 changes, causing the machining point to move on the workpiece 3. That is, the machining point shifts on the workpiece 3. The shift of the machining point means that the machining point moves along a predetermined path, specifically along a predetermined trajectory. It should be noted that the movement of the machining point involves movement in a direction orthogonal to the vertical direction of the workpiece 3. Specifically, the position of the machining point before the movement and the position of the machining point after the movement are projected at different locations onto the plane orthogonal to the vertical direction.

[0018] The additive manufacturing device 100 moves the machining point, i.e., the machining position, on the workpiece 3 and performs additive machining by depositing the machining material 7, which is melted at a predetermined machining position, at the machining point. In other words, the additive manufacturing device 100 performs additive machining by depositing the molten machining material 7 at the machining point as it moves on the workpiece 3. More precisely, the additive manufacturing device 100 drives the drive platform 6 to move candidate points for the machining position on the workpiece 3. At least one of the candidate points on the movement path is a machining point where the machining material 7 is deposited.

[0019] At the processing point, the additive manufacturing device 100 melts the material 7 supplied for additive processing with the processing light 30. The material 7 is metal wire, metal powder, or the like. In the present embodiment, the material 7 is hereinafter referred to as metal wire. The metal wire is supplied to the processing point by the material feed unit 10. For example, when the rotary motor is driven, the material feed unit 10 rotates the wire spool with the metal wire wound on it, thereby supplying the metal wire to the processing point. The material feed unit 10 can also rotate the motor in the opposite direction to pull the metal wire supplied to the processing point out.The material feed unit 10 is integrally integrated with the machining head 2 and is driven together with the machining head 2 by the drive platform 6. It should be noted that the method for feeding the metal wire is not limited to the example above.

[0020] The additive manufacturing device 100 repeatedly moves the processing point to stack beads of the molten and solidified processing material 7 on top of each other, thereby forming the object 4 on the workpiece 3. In other words, the additive manufacturing device 100 repeats the additive manufacturing process to produce the object 4. The bead is a solidified form of the molten processing material 7 and forms the object 4. In the initial stage of the additive manufacturing process, the additive manufacturing device 100 deposits the molten processing material 7 onto the workpiece 3. During the repeated additive manufacturing process, the additive manufacturing device 100 deposits the molten processing material 7 onto the object 4, which was already formed at the time of this deposition. In the first embodiment, the additive manufacturing device 100 forms a bead with a spherical shape.A bead with a spherical shape is referred to below as a spherical bead. A spherical bead is a spherical metal, which is the processing material 7 that has been melted and subsequently solidified.

[0021] The drive platform 6 can be moved along three axes: X, Y, and Z. The Z-direction is the vertical direction of the object 4. Furthermore, the X-direction is orthogonal to the Z-direction. The Y-direction is orthogonal to both the X- and Z-directions. The drive platform 6 can perform translational movement along each of the X, Y, and Z axes. The drive platform 6 can also be a five-axis platform capable of rotation in the XY and YZ planes. Using the rotational stage allows for a change in the position of the workpiece 3. By rotating the drive platform 6, the additive manufacturing device 100 can move the illumination position of the processing light 30 relative to the workpiece 3. This enables the creation of complex shapes, including tapered shapes.The drive platform 6 described here is designed to move along five axes, but the machining head 2 can also be moved instead.

[0022] The gas nozzle 9 emits a protective gas onto the workpiece 3 to prevent oxidation of the object 4 and to cool the spherical beads. In the present embodiment, the protective gas is an inert gas. The gas nozzle 9 is mounted on the lower part of the machining head 2 and positioned above the machining point. In the present embodiment, the gas nozzle 9 is arranged coaxially with the machining light 30; however, the gas can also be emitted in a direction oblique to the Z-axis towards the machining point.

[0023] The measuring illumination unit 8 emits illumination light 40 to a measuring position on the workpiece 3 in order to measure the height of the object 4 formed on the workpiece 3 by the additive manufacturing device 100. The measuring position is the same as the position of the machining point. The illumination light 40 is reflected at the measuring position. The light receiving optical system of the machining head 2 is located in a position where it can receive the illumination light 40 reflected at the measuring position. Furthermore, the light receiving optical system is arranged such that its optical axis is at an angle to the optical axis of the illumination light 40. A laser, which provides a different wavelength than that of the machining light 30, is preferably used as the light source for the measuring illumination unit 8.The illumination light 40 is a line beam, i.e., linear light. It should be noted that the illumination light 40 used to measure the height of object 4 does not necessarily have to be a line beam. The illumination light 40 can be a point beam, i.e., light concentrated in a point shape. Using the point beam allows the height of object 4 to be measured at the illuminated point on workpiece 3. Using the line beam allows the height of object 4 to be measured within the illuminated area on workpiece 3.

[0024] The calculation unit 50 calculates the height of object 4 at the machining position, i.e., at the position illuminated by the illuminating light 40. The height of object 4 is measured after the machining position has been moved and before the additive machining operation is performed at this machining position. Specifically, the calculation unit 50 calculates the height of object 4 at the machining position using the triangulation principle based on the light-receiving position of the reflected illuminating light 40. The term "light-receiving position," as used here, refers to the position of the illuminating light 40 on the light-receiving element contained in the light-receiving optical system. The height of object 4 is the position of the upper surface of object 4 in the Z-direction. The measuring illumination unit 8, the light-receiving optical system, and the calculation unit 50 define a height measurement unit.The measuring illumination unit 8 and the light reception optical system define the height sensor. The height measuring unit measures the height of the object 4 formed on the workpiece 3 at the measuring position, i.e., the machining position.

[0025] The control unit 51 uses the height calculated by the calculation unit 50 to control the processing conditions, such as the drive conditions for the processing laser 1, the drive conditions for the material feed unit 10, which feeds metal wire as processing material 7, and the number of ball beads to be stacked. The drive conditions for the material feed unit 10 include the height at which the metal wire is fed.

[0026] A hardware configuration of the computing unit 50 and the control unit 51 according to the first embodiment of the present invention is then described. The computing unit 50 and the control unit 51 are implemented by processing circuits. The processing circuits can be implemented by dedicated hardware or be a control circuit that uses a central processing unit (CPU).

[0027] If the above processing circuits are implemented by dedicated hardware, the processing circuits are defined by the in Fig. 2 processing circuits shown 190 implemented. Fig. Figure 2 is a diagram showing dedicated hardware for implementing the functions of the computing unit 50 and the control unit 51, which are located in Fig. Figure 190 shows the processing circuits. These include a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), or a combination thereof.

[0028] If the above processing circuits are implemented by a control circuit that uses a CPU, this control circuit is, for example, a control circuit 200 with the in Fig. 3 configurations shown. Fig. Figure 3 is a diagram showing a configuration of the control circuit 200 for implementing the functions of the computing unit 50 and the control unit 51, which are described in Fig. 1 are shown. As in Fig. As shown in Figure 3, the control circuit 200 includes a processor 200a and a memory 200b. The processor 200a is a CPU and is also referred to as a central processing unit, processing unit, computing unit, microprocessor, microcomputer, digital signal processor (DSP), or the like. The memory 200b is, for example, a non-volatile or volatile semiconductor memory, a magnetic disk, a flexible disk, an optical disk, a compact disc, a mini-disc, a digital versatile disk (DVD), and the like. Examples of non-volatile or volatile semiconductor memories include random-access memory (RAM), read-only memory (ROM), flash memory, erasable programmable ROM (EPROM), electrical EPROM (EEPROM; registered trademark), and the like.

[0029] If the processing circuits described above are implemented by the control circuit 200, the processor 200a reads and executes the program corresponding to the process of each component stored in memory 200b, thereby implementing the processing circuits. Memory 200b is also used as temporary storage for each process executed by the processor 200a.

[0030] Fig. 4 is a diagram showing the internal configuration of the Fig. 1 shows the processing head 2. Fig. Figure 4 shows the configuration of the additive manufacturing device 100 in the XZ cross-section. The processing head 2 includes a light-projecting lens 11, a beam splitter 12, an objective lens 13, a bandpass filter 14, a converging lens 15, and a light receiver 16.

[0031] The light-projecting lens 11 transmits the processing light 30 emitted by the processing laser 1 to the beam splitter 12. The beam splitter 12 reflects the processing light 30 incident on the light-projecting lens 11 to the workpiece 3. The objective lens 13 concentrates the processing light 30 incident via the light-projecting lens 11 and the beam splitter 12 and focuses the processing light 30 onto the processing position on the workpiece 3. The light-projecting lens 11, the beam splitter 12, and the objective lens 13 define the processing optical system.

[0032] The focal length of the light-projecting lens 11 is, for example, 200 mm, and the focal length of the objective lens 13 is 460 mm. The surface of the beam splitter 12 is coated to increase the reflectance at the wavelength 30 of the processing light emitted by the processing laser 1 and to transmit light with a wavelength shorter than the wavelength of the processing light 30.

[0033] The additive manufacturing device 100 drives the drive platform 6 to move the workpiece 3, causing the processing point to move and stop at a predetermined position. The additive manufacturing device 100 then delivers the processing material 7 to the processing point. Irradiation of the processing point with the processing light 30 causes the delivered processing material 7 to melt and then solidify, forming a spherical bead on the workpiece 3. This spherical bead is part of the object 4. Each time the processing point moves, a new spherical bead is deposited on the workpiece 3, which serves as the base, or on the formed object 4. Consequently, a new part of the object 4 is formed. This process is repeated, depositing the processing material 7 in layers in the desired shape of the object 4.

[0034] The measuring illumination unit 8 emits the illumination light 40 to the measuring position. The illumination light 40 reflected at the measuring position enters the bandpass filter 14 via the objective lens 13 and the beam splitter 12. The beam splitter 12 directs the illumination light 40 from the processing point towards the bandpass filter 14. The bandpass filter 14 selectively transmits light with the wavelength of the illumination light 40 and blocks light with a different wavelength. The bandpass filter 14 removes light with an unnecessary wavelength, such as processing light, heat radiation, and ambient light, and transmits the illumination light 40 towards the converging lens 15. The converging lens 15 concentrates the illumination light 40 and focuses it onto the light receiver 16.The light receiver 16 is an area camera or the like, equipped with a light-receiving element, such as a complementary metal oxide semiconductor (CMOS) image sensor. Instead of the CMOS sensor, the light receiver 16 can include any light-receiving element in which pixels are arranged in a two-dimensional manner.

[0035] The objective lens 13 and the converging lens 15 are collectively referred to as the light-receiving optical system. The light-receiving optical system described herein includes two lenses, but three or more lenses can also be used. The light-receiving optical system can be configured in any way that allows the illumination light 40 to be focused onto the light receiver 16. The light-receiving optical system and the light-receiving element are collectively referred to as the light-receiving unit 17.

[0036] Fig. 5 is a flowchart to illustrate a process in which the in Fig. 1 The device shown for additive manufacturing forms a spherical bead.

[0037] First, the additive manufacturing device 100 drives the drive platform 6 to position the machining head 2 at the machining point, which is a predetermined position above the machining area on the additive target surface of the workpiece 3 (step S101). The term "additive target surface" used here, i.e., the surface of the workpiece 3 on which the spherical beads are stacked, refers to the upper surface of the workpiece 3 placed on the platform. If the additive machining is performed on the already formed object 4, the additive target surface is the surface of the object 4.

[0038] Fig. 6 is a schematic cross-sectional diagram showing the processing area of ​​the Fig. The device for additive manufacturing shown in Figure 1 is 100. As shown in Fig. As shown in Figure 6, the processing point is a point where a central axis CL of the processing light 30 and the additive target surface intersect. In the present embodiment, the processing point is the central position of the processing area on the additive target surface.

[0039] Now, the focus is shifting back to... Fig. 5 Reference is made. The additive manufacturing device 100 outputs metal wire as processing material 7, so that the end of the wire comes into contact with the additive target surface (step S102).

[0040] Fig. 7 is a schematic cross-sectional diagram in which the wire leading to the processing area of ​​the in Fig. The device shown in Figure 1 for additive manufacturing outputs 100 units, which are in contact with the additive target surface. As shown in Figure 1. Fig. As shown in Figure 7, the additive manufacturing device 100 dispenses the processing material 7, i.e., the wire, at an oblique angle above the processing area to bring the end of the processing material 7 into contact with the additive target surface. Dispensing the wire means that the additive manufacturing device 100 controls the processing material feed unit 10 to cause the wire to be advanced from the wire nozzle to be delivered to the processing point. Before the processing area is irradiated with the processing light 30, the processing material 7 is in contact with the additive target surface. In this way, the molten wire is stably welded onto the additive target surface, and it is prevented that molten wire is not welded to the additive target surface or is welded at a position far from the desired position.

[0041] It is preferred that the central axis CW of the wire exiting the wire nozzle and coming into contact with the additive target surface intersects the central axis CL of the processing light 30 emitted onto the processing area at the surface of the additive target surface. Alternatively, it is preferred that the central axis CW of the wire and the surface of the additive target surface intersect within the beam radius of the processing light 30 between the wire nozzle and the central axis CL of the processing light 30 emitted onto the processing area. Positioning the wire in this way enables the formation of a spherical bead on the additive target surface, such that the center of the formed spherical bead is located at the intersection of the central axis CW of the wire and the central axis CL of the processing light 30 emitted onto the processing area.

[0042] Now, the focus is shifting back to... Fig. 5. Reference is made. Once the preparation of the processing material 7 is complete, the additive manufacturing device 100 begins to emit the processing light 30 and expels inert gas from the gas nozzle 9 (step S103).

[0043] Fig. Figure 8 is a schematic cross-sectional diagram showing the processing area of ​​the Fig. The device for additive manufacturing 100 shown in Figure 1 is irradiated with the processing light 30. As in Fig. As shown in Figure 8, the processing light 30 is emitted in the direction of the processing area of ​​the additive target surface. The processing light 30 is emitted towards the wire, i.e., the processing material 7, which is located in the processing area. Simultaneously with the emission of the processing light 30, inert gas is discharged from the gas nozzle 9 onto the processing area. It is preferred that the discharge of inert gas begins before the surface to be processed is irradiated with the processing light 30. It is also preferred that the inert gas is discharged for a predetermined, fixed period. Discharging inert gas for this fixed period before the emission of the processing light 30 allows any remaining active gas, such as oxygen, from the gas nozzle 9 to be removed.

[0044] Now, the focus is shifting back to... Fig. 5. Reference is made to the additive manufacturing device 100, which begins to feed the wire, i.e., the processing material 7 (step S104).

[0045] Fig. 9 is a schematic cross-sectional diagram showing the wire feed to the processing area of ​​the Fig. The additive manufacturing device 100 shown in Figure 1 was started. The additive manufacturing device 100 controls the wire nozzle of the processing material feed unit 10 such that the wire is fed in the direction of the arrow from Fig. 9 is emitted to the processing area of ​​the additive target surface. This melts the wire previously positioned in the processing area and the wire fed to the processing area after the processing light 30 begins to be emitted, and the molten wire is welded onto the additive target surface. In the processing area, the additive target surface, defined by the surface of the workpiece 3 or the surface of the object 4, is melted into a molten pool upon emission of the processing light 30. Subsequently, the molten wire is welded onto the molten pool in the processing area. This forms a deposit or a molten bead in the processing area. The wire feed to the processing area then continues for a predetermined feed time.

[0046] The wire feed speed can be adjusted by the rotational speed of the rotary motor of the material feed unit 10. The wire feed speed is limited by the output power of the processing light 30. That is, there is a correlation between the wire feed speed and the output power of the processing light 30 in achieving proper welding of the molten wire onto the processing area. It is possible to increase the speed of bead production by increasing the output power of the processing light 30.

[0047] If the wire feed rate is too high relative to the output power of the processing light 30, the wire remains unmelted. If the wire feed rate is too low relative to the output power of the processing light 30, the wire overheats, causing molten wire to fall off the wire in droplets without being welded into the desired shape.

[0048] The size of a bead can be adjusted by changing the wire feed time and the duration of the light emission 30. The longer the wire feed time and the duration of the light emission 30, the larger the diameter of the resulting bead. Conversely, the shorter the wire feed time and the duration of the light emission 30, the smaller the diameter of the resulting bead.

[0049] Now, the focus is shifting back to... Fig. 5. Reference is made. Once the additive machining at the first machining position is completed, the additive manufacturing device 100 withdraws the wire, i.e. the machining material 7, from the machining area (step S105).

[0050] Fig. 10 is a schematic cross-sectional diagram in which the wire from the processing area of ​​the in Fig. The additive manufacturing device 100 shown in Figure 1 is pulled out. Once the additive machining is complete at the first machining position, the additive manufacturing device 100 pulls the wire, i.e., the machining material 7, in the direction indicated by the arrow. Fig. As indicated in point 10, the process is carried out from the processing area. The melt pool formed on workpiece 3 and the molten bead are integrated together, and the withdrawal of the wire separates the wire from the molten bead.

[0051] Now, the focus is shifting back to... Fig. 5. Reference is made to this. After the wire has been withdrawn, the additive manufacturing device 100 stops emitting the processing light 30. Furthermore, after stopping the emission of the processing light 30, the additive manufacturing device 100 continues to expel inert gas from the gas nozzle 9. Subsequently, after a certain period of time, the additive manufacturing device 100 stops expelling inert gas from the gas nozzle 9 (step S106).

[0052] Fig. 11 is a schematic cross-sectional diagram showing the irradiation of the processing area of ​​the in Fig. The additive manufacturing device 100 shown in Figure 1 is stopped using the processing light 30. After the irradiation of the processing area with the processing light 30 is stopped, the emission of inert gas continues for a certain period. After this period has elapsed, the emission of inert gas is stopped, and subsequently the molten bead solidifies to form a spherical bead on the additive target surface.

[0053] The time period is determined based on the duration from the moment the processing light 30 is stopped until the temperature of the molten bead welded to the processing area has dropped to a predetermined temperature. The time required for the molten bead to drop to a predetermined temperature depends on various conditions, such as the wire material and the size of the bead. The time period, based on these conditions, is pre-stored in the control unit 51. After the time period has elapsed, the temperature of the molten bead drops to the predetermined temperature, and the formation of the bead is complete.

[0054] Now, the focus is shifting back to... Fig. 5. Once the additive machining at the first machining position is complete and the spherical bead has been formed, the additive manufacturing device 100 positions the machining head 2 at the next machining point (step S107). In particular, the additive manufacturing device 100 controls the drive platform 6 such that the relative position between the workpiece 3 and the machining head 2 is changed, thereby positioning the machining head 2 above the second machining position, which is the next machining point.

[0055] Fig. 12 is a schematic cross-sectional diagram in which the processing head 2 of the in Fig. The device shown in Figure 1 for additive manufacturing moves 100 to the next processing point. It should be noted that Fig. 6 to Fig. 12. Show the state of a circumferential region of the machining area on the additive target surface. In Fig. 8 to Fig. Figure 11 does not show the inert gas.

[0056] The arrow in Fig. Figure 12 indicates the direction of movement of the machining head 2 relative to the workpiece 3, and the central axis CL of the machining light 30 moves together with the movement of the position of the machining head 2 relative to the workpiece 3 in the direction of the arrow relative to the workpiece 3. The central axis CL is moved to the second machining position, which is the next machining point.

[0057] Fig. Figure 13 is a schematic cross-sectional diagram illustrating a process for producing item 4 with the in Fig. Device for additive manufacturing shown in 1 100. By repeating the steps shown in Fig. In the steps shown, it is possible to form a layer of spherical beads that constitute the object 4 on the additive manufacturing target surface. The layer of spherical beads formed directly on the surface of the workpiece 3 is referred to as the first layer A. Furthermore, the layer of spherical beads formed on top of the first layer A is referred to as the second layer B. The layer of spherical beads formed on top of the second layer B is referred to as the third layer C. By stacking several layers of spherical beads, the additive manufacturing device 100 can form the object 4 with a desired shape on the workpiece 3. The additive manufacturing device 100 changes the position of the drive platform 6 in the Z-axis direction by a specific amount each time the additive manufacturing of the respective layer is completed.It is preferred that the amount of change in the direction of the Z-axis is equal to the height of the spherical bead to be formed.

[0058] The steps mentioned above do not necessarily have to be performed in the order described above. The present embodiment is not limited to the example described above, in which, when the machining position is moved and a spherical bead is produced, the step of positioning the machining head 2 over the machining point is separate from the step of dispensing wire. To reduce the machining time, the movement to the next machining point can occur during the dispensing of the wire. This allows the wire to be in contact with the additive target surface by the time it arrives at the next machining point, resulting in a reduction of the machining time.

[0059] It is preferred that the item 4 be manufactured with a planned height; however, the height of the applied spherical beads can vary depending on the additive manufacturing conditions, resulting in an item 4 with a height that differs from the planned height. Examples of additive manufacturing conditions include the shape of the additive target surface, the wire feed position, the wire withdrawal situation, and the like. If the height of the wire relative to the additive target surface is not within the optimal range, the spherical bead cannot be manufactured with high accuracy. For example, if the position of the wire relative to the additive target surface is too high, the molten wire will not adhere sufficiently to the additive target surface.If the position of the wire is too low relative to the additive target surface, the wire cannot be melted sufficiently, and a molten residue may remain.

[0060] Fig. 14 is a diagram showing the height of the wire relative to the object 4, which passes through the in Fig. The device for additive manufacturing 100 shown in Figure 1 is used to form the wire. The wire height refers to the height of the wire feed port relative to the additive target surface, such as the top surface of the workpiece 3 or the top surface of a spherical bead. The wire height can also be the height of the wire end, as the wire end height can be calculated using the set output amount from the wire feed port. The suitable range for the wire height depends on the height of the formed object 4.

[0061] As in Fig. As shown in Figure 14, an error in the wire feed at a height corresponding to the formed object 4 causes a defect in the processing result. For example, it is assumed that a suitable range of wire heights corresponding to the one shown in Figure 14 would result in a defect in the processing result. Fig. The object depicted in 14 corresponds to 4, ha±α. In Fig. 14(a) the height of the wire lies in the middle of the region ha±α. In other words, the height of the wire in Fig. 14(a) ha. A lower limit 20 of the wire height is ha-α, and an upper limit 21 of the wire height is ha+α. Since in Fig. 14(a) if the height of the wire is ha, which lies within the range ha±α, no error occurs in the processing result.

[0062] In Fig. 14(b) However, the height of the formed spherical bead, which serves as the surface to be processed, is smaller than the planned value, and the wire has a height hb that satisfies hb>ha+α, which is outside the range ha±α. In this case, the wire, which is melted by irradiation with the processing light 30, does not adhere sufficiently to the formed object 4, resulting in a droplet 71 that causes an unevenness on the resulting object 4.

[0063] In Fig. 14(c) the height of the formed spherical bead, which serves as the surface to be machined, is greater than the planned value, and the wire has a height hc which hc <ha-α erfüllt, was außerhalb des Bereichs ha±α liegt. In diesem Fall wird der Draht zu stark in Richtung des gebildeten Gegenstands 4 gedrückt; dadurch wird der Draht nicht vollständig geschmolzen, auch wenn er mit dem Bearbeitungslicht 30 bestrahlt wird, und es bleibt ein Schmelzrückstand 72 des Drahtes zurück. Dadurch enthält der resultierende Gegenstand 4 den nicht geschmolzenen Draht. Daher ist es für eine hochpräzise Bearbeitung unerlässlich, die Höhe des Drahtes auf einem angemessenen Wert in Übereinstimmung mit dem Zustand des gebildeten Gegenstands 4 zu halten.

[0064] During additive manufacturing to create the first layer, defined by the object 4 deposited on the upper surface of workpiece 3, the wire height only needs to be kept constant if the upper surface of workpiece 3 is flat. For the second and subsequent layers, additive manufacturing must be performed on the previous layer of the formed object 4. If the height of the formed object 4 is as planned, the wire height only needs to be controlled based on that planned value. However, the height of the formed object 4 is not always as planned.In this case, increasing the wire height by the planned height of a layer can, in practice, result in the wire height in a section of the formed object 4 being outside the suitable range, since this section of the object 4 has a height that differs from the planned value. Even if the wire height for forming the second layer is within the permissible range ha±α, i.e., within the permissible error range, the error can accumulate n(n≥2) times over several repetitions of the additive machining process to form an nth layer. Therefore, in this case, the wire height may not be within the permissible error range. Considering this fact, the present embodiment measures the height of the object 4 as it is machined in practice and controls the machining conditions based on the measurement result.

[0065] Next, a method for measuring the height of the formed object 4 using the height measurement unit is described. Fig. 15 is a diagram that schematically shows an XZ cross-section of item 4, which is shown by the in Fig. The measuring illumination unit 8, shown in Figure 1, projects the illumination light 40. The measuring illumination unit 8 is mounted on a lateral surface of the machining head 2 and emits the illumination light 40, which is a line beam, towards the measuring position on the workpiece 3 or the formed object 4. The measuring position is determined, for example, by considering the direction of feed of the machining material 7. For instance, the measuring position may be on the side opposite the direction of feed of the machining material 7, with the machining point located between them. In this case, the measuring position can be easily illuminated without being blocked by the machining material 7.The illumination light 40 is shaped using a cylindrical lens or the like to form a beam extending in the Y direction, which is perpendicular to the direction in which the wire is fed and parallel to the upper surface of the drive platform 6. In this way, the illumination light 40 is emitted linearly onto the formed object 4. The illumination light 40 emitted towards the measuring position is reflected at the measuring position, enters the objective lens 13, passes through the beam splitter 12 and the bandpass filter 14, and is focused by the converging lens 15 onto the light receiver 16.

[0066] Now, consider a case where the focal point of the light-receiving optical system of the height sensor lies at the height of the processing position of the spherical bead. The height of object 4 relative to the upper surface of workpiece 3 is denoted by ΔZ, and the irradiation angle of the illumination light 40 is denoted by 8. In this case, a difference ΔX between the illumination position of the illumination light 40 on the upper surface of workpiece 3 and the irradiation position of the illumination light 40 on object 4 is expressed as ΔX = ΔZ / tanθ.

[0067] Fig. Figure 16 is a diagram showing the light-receiving position on the light-receiving element, with object 4 being represented by the in Fig. In Figure 1, the additive manufacturing device 100 is illuminated with the illumination light 40. The projection position of the illumination light 40, corresponding to the focal point of the light-receiving optical system, is defined as the pixel center in the X direction and is called the reference pixel position. The projection position of the illumination light 40 in the X direction at a position corresponding to the processing position in the Y direction is defined as the ball bead height at the processing position. The processing position CL is set to be the midpoint in the Y direction on the light-receiving element, but it need not be the midpoint. A value calculated from a pixel in the Y direction corresponding to the processing position CL can be used. Alternatively, an average value of a multitude of pixels can be used.

[0068] The reference pixel position does not have to be the focal point of the light-receiving optical system and can be freely set. Since the illumination light 40 is projected onto the processing position on the spherical bead, which is the focal point of the light-receiving optical system, the focal point of the light-receiving optical system is the reference pixel position on the light-receiving element.

[0069] The height of object 4 differs from the height of the surface of workpiece 3; therefore, the illumination position of the light source 40 is projected with a displacement of ΔX'. When using a magnification M of the light-receiving optical system, ΔX' = M × ΔX. Assuming that the size of a pixel of the image sensor is P, a height displacement ΔZ' per pixel is expressed as ΔZ' = P × tan θ / M. The computation unit 50 can thus calculate the height of the spherical bead from the upper surface of workpiece 3 by converting the displacement of the projection position of the illumination source 40 between the processing position of the spherical bead on the light-receiving element and the surface of workpiece 3 using the triangulation principle.

[0070] Furthermore, in the case of additive machining of multiple layers, the drive platform 6 is raised by a specific amount in the Z-direction each time a layer is deposited; this increases the height of the machining head 2 and the height sensor relative to the upper surface of the workpiece 3. In this way, the focus position of the height sensor also increases when the drive platform 6 is raised. Therefore, the height in the Z-direction, i.e., the reference pixel position, also increases. The calculation of the difference from the reference pixel position is repeated, whereby the height of the object 4 relative to the upper surface of the workpiece 3 can become so high that the light-receiving element is no longer able to receive the light of the illumination 40 reflected from the upper surface of the workpiece 3.Even in such a case, it is possible to calculate the height of object 4 from the integral of the cumulative magnitude of the slope along the Z-axis and the difference between the reference pixel position and the irradiation position of the illumination light 40 reflected from the upper surface of object 4 in the field of view on the light-receiving element. Assuming that the number of pixels of the light-receiving element in the X-direction is N pixels, a region Zr in which the height of object 4 is measurable is expressed as Zr = N × tan θ / M. It should be noted that it is not necessary to use every pixel in the X-direction of the light-receiving element as a region for height measurement. Rather, only the center of the field of view can be used if the performance at the edge of the field of view is low, for example, due to the influence of an aberration.

[0071] The processing unit 50 calculates the irradiation position of the illumination light 40, which is a line ray, based on the centroid position of the projection pattern of the illumination light 40 in the X-direction. The processing unit 50 calculates an output in the X-direction for each pixel in the Y-direction and calculates the centroid position from the cross-sectional intensity distribution of the illumination light 40. The method for calculating the irradiation position of the illumination light 40 is not limited to using the centroid position. For example, the processing unit 50 can calculate the irradiation position of the illumination light 40 based on the peak position of the light quantity. The irradiation width of the illumination light 40, i.e., the length of the line ray, must be large enough to allow for a calculation of the irradiation position.When using the center of gravity position, for example, an insufficient irradiation width prevents the calculation of the center of gravity position, and an excessively large irradiation width can cause errors due to the influence of changes in the beam intensity pattern. Therefore, the irradiation width should ideally be between 5 and 10 pixels. Furthermore, the irradiation width of the illumination light 40 should be sufficiently larger than the width of the object 4. If it is not necessary to perform a center of gravity calculation for all Y-direction pixels of the projected line beam to calculate the height, for example, if the proximity of the processing position CL is sufficient, it is possible to use only the area near the processing position CL.

[0072] As discussed above, calculating the luminance center position in the X-direction for each pixel of the image in the Y-direction and converting the result of this calculation into height allows the cross-sectional distribution of the height of object 4 in the width direction of object 4 to be measured. In a case where the illuminant 40 used to measure the height of object 4 is a point beam, the cross-sectional distribution of the height of object 4 cannot be measured; however, an appropriate selection of the spot size allows for a measurement with fewer errors.

[0073] Next, a method for the additive process using the result of measuring the height of the formed object 4 is described. Fig. Figure 17 is a flowchart illustrating a process for carrying out an additive process using the result of measuring the height of object 4, which is measured by the in Fig. 1 device for additive manufacturing 100 is formed.

[0074] The following example case is based on the assumption that a layer consists of m spherical beads and that n layers of m spherical beads are stacked on top of each other. First, the additive machining of the first layer begins (step S201). If the top surface of workpiece 3 is a flat base plate, no bead is at the measuring position during the additive machining of the first layer, and therefore it is not necessary to measure the height. However, a height measurement can be performed during the formation of the first layer to ensure precise additive machining, taking into account the stacking of spherical beads on the workpiece 4, or, for example, if the base plate is deformed. The measurement of the first layer's height is performed during the process of Fig. 17 not carried out. It should be noted that the specific processing in step S201 is that which is in Fig. 5 is shown.

[0075] Once the entire additive processing of the first layer is complete, the additive manufacturing device 100 raises the drive platform 6 in the Z direction to perform the additive processing of the second layer (step S202). The additive manufacturing device 100 moves the drive platform 6 so that the processing head 2 arrives at the processing position where the first ball bead is to be produced (step S203).

[0076] The additive manufacturing device 100 begins at the processing position by measuring the height of the object 4 formed in the first layer (step S204). The additive manufacturing device 100 stores the result of the measurement of the height of the formed object 4 (step S205). The measuring position is the processing position of the spherical bead that is to be produced next.

[0077] The additive manufacturing device 100 performs the additive processing, during which it controls the processing conditions using the result of the height measurement of object 4 stored in step S205 (step S206). The additive manufacturing device 100 determines whether the production of m spherical beads in the current layer is complete (step S207).

[0078] In response to the determination that the production of m spherical beads is not complete (step S207: no), the additive manufacturing device 100 returns to step S203. In response to the determination that the production of m spherical beads is complete (step S207: yes), the additive manufacturing device 100 subsequently determines whether the production of n layers is complete (step S208). In response to the determination that the production of n layers is not complete (step S208: no), the additive manufacturing device 100 returns to step S202. In response to the determination that the production of n layers is complete (step S208: yes), the additive manufacturing device 100 terminates the additive manufacturing process.The additive manufacturing device 100 repeats steps S201 to S208 so that the item 4 can be produced with a predetermined shape as a result of additive manufacturing.

[0079] Next, details of the processing control will be described. Fig. Figure 18 is a diagram showing a method for controlling the wire feed rate when the in Fig. The device shown in Figure 1 for additive manufacturing processes the second layer. Region I represents the case where the practical height T1 of the object 4 formed in the first layer is equal to the target height T0 of the object 4. The target height T0 is a preset height for a newly deposited layer on the object 4. In Region II, the practical height T2 of the object 4 formed in the first layer is greater than the target height T0. In Region III, the practical height T3 of the object 4 formed in the first layer is less than the target height T0. For simplicity, the wire height, i.e., the height of the wire end used to produce the object 4 with a target stack height, is set to the target height T0. In practice, however, the wire height used to produce the object 4 with a target stack height may differ from the target height T0.

[0080] In the case of processing the second layer in area I, the height T1, i.e., the measurement result of the first layer, is the same as the target height T0; therefore, the control unit 51 does not change any of the processing conditions. In the case of processing the second layer in area II, the height T2, i.e., the measurement result of the first layer, is greater than the target height T0. Even if the wire height relative to the additive target surface can be within the permissible range ha±α during the formation of the first layer, the wire height deviates from the permissible range due to continuous additive processing. Therefore, to produce the second layer with a stack height of 2×T0, it is necessary to set the stack height of the second layer to 2×T0-T2.

[0081] Examples of processing conditions for changing the stack height include, for example, the wire feed rate (i.e., the wire feed quantity), the output power of the processing laser 1, the duration of the emission of the processing light 30 from the processing laser 1, the number of spherical beads to be stacked, and the extent of the feed of the drive platform 6 in the Z-direction. In this example, the wire feed rate is controlled.

[0082] Controlling the wire feed rate allows the amount of wire supplied to the processing point during the emission of the processing light 30 to be controlled. Let v1 be the wire feed rate for producing a deposit with the target height T0 in area I. In area II, the stack height must be smaller than in area I. The control unit 51 therefore uses a wire feed rate v2, which is lower than v1, to reduce the amount of wire supplied, so that the object 4, consisting of the first and second layers, has a height of 2×T0 at the end of the processing of the second layer.

[0083] In area III, the height T3, i.e., the measured value, is less than the target height T0; therefore, it is necessary to set the stack height of the second layer to 2×T0-T3. The control unit 51 thus uses a wire feed rate v3, which is higher than v1, to increase the amount of wire fed, so that the object 4, consisting of the first and second layers, has a height of 2×T0 at the end of the second layer processing. In summary, the control unit 51 controls the processing conditions based on the difference between the measured value and the target height T0, thereby controlling the stack height for the next additive processing step. The control value for the wire feed rate only needs to be determined by pre-calculating and recording the relationship between the wire feed rate and the height of the bead to be deposited.In a case where a large number of layers are stacked on top of each other, the control value can be dynamically changed during additive manufacturing, using the stacking result based on the measured bead height of the previous layer.

[0084] In the description above, the wire feed rate is changed to alter the stack height for additive manufacturing; however, a parameter other than the feed rate can also be changed. Alternatively, the machining conditions can be controlled by changing several types of parameters. For example, to reduce the stack height, the machining laser 1 can reduce its output power and emit the machining light 30 for a shorter period. Conversely, to increase the stack height, the machining laser 1 can increase its output power and emit the machining light 30 for a longer period.

[0085] Fig. 19 is a diagram showing an example where the processing condition, which is in Fig. The device shown in Figure 1 for additive manufacturing controls the number of spherical beads. The situation at the end of the processing of the first layer is similar to that in [reference missing]. Fig. 18. In the case of processing the second layer in area I, where the target height of the second layer is set to T4, the height T1, i.e., the measurement result of the first layer, is equal to the target height T0 of the first layer. The control unit 51 therefore performs the additive processing without changing the processing condition. In area II, the height T2, i.e., the measurement result, is greater than the target height T0 and close to the target height T0+T4, which should be reached at the end of the additive processing of the second layer. In area II, the control unit 51 therefore does not perform additive processing of the second layer. In area III, the height T3, i.e., the measurement result, is less than the target height T0, and the difference between the target height T0+T4, which should be reached at the end of the additive processing of the second layer, and the height T3 is twice T4 or more. Thus, two layers of spherical beads are continuously formed and stacked on top of each other.In summary, the control unit 51 changes the number of spherical beads to be stacked based on the difference between the target height and the measured value. Changing the number of spherical beads to be stacked effectively counteracts the increasing difference between the target height and the measured value during the process of forming a stack of n layers. Since precise height control using only the number of spherical beads to be stacked is difficult, it is preferable to control the number of spherical beads to be stacked while simultaneously changing other control parameters, such as the wire feed speed.

[0086] Fig. 20 is a diagram showing a procedure in which the in Fig. 1. The additive manufacturing device shown controls the wire height based on the result of the measurement of the object's height. 4. The situation at the end of the first layer processing is similar to that in Fig. 18. For example, it is assumed that the heights of the object 4 of the first layer in regions II and III differ significantly from the target height T0. If the wire height is increased by T0 during the additive machining of the second layer in regions II and III, the wire height relative to the additive target surface may lie outside the permissible range ha±α. In such a case, it is preferred to control the wire height by changing the amount of lifting of the drive platform 6 in the Z-direction.

[0087] When additively machining the second layer in area I, the wire height only needs to be set to T0, since the height T1, i.e., the measurement result of the first layer, is equal to the target height T0. In the case of machining the second layer in area II, where the height T2, i.e., the measurement result, is greater than the target height T0, the wire height is outside the permissible range if it is set to T0. Therefore, the wire height is set to T2, which allows the additive machining of the second layer to be carried out without causing a machining error. In additively machining the second layer in area III, the wire height is outside the permissible range if it is set to T0, because the height T3, i.e., the measurement result, is less than the target height T0.In view of this fact, the wire height for machining is set to T3, which makes it possible to perform additive machining of the second layer without causing a machining error.

[0088] The wire height adjustment described above, based on the measurement of the height of the formed object 4, makes it possible to prevent processing errors. Wire height is one example of a processing condition. It is preferred that the wire height control be carried out in conjunction with the control of processing conditions for changing the stack height, which differ from the wire height, such as the wire feed rate, the output power of the processing laser 1, the duration of the emission of the processing light 30, and the like.

[0089] If there is a large difference between the average height of the (n-1)th layer and the target height T0 before the nth layer is processed, the amount of change in wire height to be increased can be set to the average height of the (n-1)th layer instead of the planned value T0 at the end of processing the (n-1)th layer.

[0090] For processing the nth layer, the processing conditions are controlled using the result of the immediately preceding measurement of the stack height of the (n-1)th layer, so that the difference between the target height and the wire height can be kept within the permissible range ha±α, as described in Fig. 14 is shown. Thus, processing can continue without causing a processing error, and the production accuracy of item 4 can be improved.

[0091] In the present embodiment, a configuration has been described in which the height sensor and the machining head 2 are integrated. However, the height sensor and the machining head 2 need not be integrated. In the case of a machining head 2 and a height sensor provided separately from the machining head 2, the drive platform 6 is moved for the purpose of height measurement so that the machining position coincides with the measurement position of the height sensor. After the height measurement by the height sensor, the drive platform 6 is moved for the purpose of machining so that the machining position coincides with the illumination position of the machining light 30. An integrated height sensor and machining head 2 enable a reduction in the time required for height measurement. It should be noted that in the present embodiment, the height sensor uses a line beam as the illumination light 40.If the height sensor and the processing head 2 are not integrated together and the converging lens 15 is not used for the two purposes of processing and height measurement, it is preferred in this context that the converging lens 15 is an optical system capable of focusing only one line beam onto the light receiver 16.

[0092] In the present embodiment, the spherical beads have a hemispherical shape, but they can have any shape other than a hemispherical shape, as long as a plurality of beads, each consisting of a lump of the processing material 7 formed on a stationary drive platform 6, are arranged in such a way as to form the object 4. Fig. 21 is a diagram showing a modification of the shape of a pearl, which is caused by the in Fig. The device shown in 1 for additive manufacturing was formed. Fig. The exemplary bead shown in Figure 21, which is a hemisphere with a recessed center, also enables high-precision additive manufacturing through the use of the height sensor and the control of the processing conditions according to the present embodiment. Beads with other shapes can also be used without difficulty, as long as the beads are formed into a spherical shape.

[0093] In the present embodiment, the center of a spherical bead is defined as the processing position; however, similar effects can also be achieved if the processing position deviates from the center of a spherical bead. Fig. 22 is a diagram showing a modification of the measuring position for measuring the height of the object 4, which is defined by the Fig. The device for additive manufacturing 100 shown in Figure 1 was formed. Assuming that the processing position for producing a deposit at the center of a spherical bead, as described in the present embodiment, is CL0, the processing conditions can be controlled based on the result of the measurement at CL0 as the measuring position of the illumination light 40. However, depending on the shape to be produced, a deposit can also be produced at a position other than the center of a spherical bead. Possible examples include the processing positions CL1 and CL3 on the curved surfaces of the Fig. Figure 22 shows spherical beads and a machining position CL2 located at the junction between adjacent spherical beads. In these cases, the bead height is less than the height T1 of the center of the spherical bead. However, as described in the present embodiment, high-precision machining can be performed by measuring the height of the object 4 formed at the machining position using the illumination light 40, which is a line beam, and by controlling the machining conditions.

[0094] Furthermore, in the present embodiment, the height of the formed object 4 is measured before a spherical bead is formed, with deposition occurring after the measurement and movement to the next processing point. However, the present embodiment is not limited to this example. For instance, after the additive processing of a single layer is completed, the height of the formed object 4, defined by the entire single layer, can be measured, and the processing conditions for the additive processing of the nth layer can be controlled based on the measurement result.

[0095] Since the processing point for deposition is moved in the X-direction or in the Y-direction, it is also unnecessary in the present embodiment to wait until the molten processing material 7 has completely solidified, and it is possible to measure the bead height in the (n-1)th layer with the fully solidified beads. This allows for both an improvement in measurement accuracy and a reduction in processing time. To achieve continuous deposition in the Z-direction, the measurement of the height of the object 4 and the additive processing of the nth layer are carried out after a time has elapsed for the bead in the (n-1)th layer to completely solidify.

[0096] As described above, according to the first embodiment of the present invention, the practical height of the formed object 4 is measured, and the processing conditions are controlled based on the measurement result. This allows an object 4 with a uniform height to be produced, and the dimensional accuracy of the object 4 can be improved. Second embodiment.

[0097] Since the configuration of the device for additive manufacturing 100 according to the second embodiment of the present invention is the same as that of the one described in Fig. The additive manufacturing device 100 shown in Figure 1, according to the first embodiment, will not be described in detail here. Furthermore, the additive manufacturing device according to the second embodiment will be designated by 100, the reference numeral also used in the first embodiment. The following section mainly describes the differences from the first embodiment.

[0098] Fig. Figure 23 is a diagram illustrating the problem that the additive manufacturing device 100, according to the second embodiment of the present invention, is intended to solve. In the present embodiment, the control unit 51 includes a machining position search unit that searches for the machining position when the height of the formed object 4 is measured. In the light sectioning method, where a line beam is emitted obliquely, the measuring position is shifted laterally in response to a change in the height of the object 4. However, the machining position search unit makes it possible to measure the height of the machining position with high accuracy, independent of the height of the object.

[0099] Fig. Figure 23(a) shows a case in which a spherical bead is formed as planned with the target height T1. During the deposition of the second layer, the processing head 2 is raised by the amount corresponding to the height T1 of the spherical bead; moving the drive platform 6 into the position for measuring the processing position therefore results in (processing position CL) = (measuring position CH), whereby the height of the object 4 can be measured at the processing position.

[0100] Fig. Figure 23(b) shows a case in which the height T2 of a spherical bead in the first layer is greater than the target height T1. During the deposition of the second layer, raising the processing head 2 by T1 and moving the drive platform 6 to the position for measuring the processing position do not result in (processing position CL) = (measuring position CH), but rather cause a difference of ΔX2.

[0101] Fig. Figure 23(c) shows a case in which the height T3 of a spherical bead in the first layer is less than the target height T1. During the deposition of the second layer, raising the processing head 2 by T1 and moving the drive platform 6 to the position for measuring the processing position do not result in (processing position CL) = (measuring position CH), but rather cause a difference of ΔX3.

[0102] As described above, in the light sectioning method, where a line beam is emitted obliquely, a displacement of the height of the formed object 4 from the target height T1 causes a displacement of the measurement position. If the upper surface of object 4 is flat, the influence of the displacement of the measurement position is small. However, if object 4 has a curved shape, such as that of a spherical bead, the displacement of the measurement position leads to a significant reduction in the accuracy of the measurement of object 4's height. This reduction in the accuracy of the height measurement can cause the wire height relative to the additive target surface to be outside the permissible range, which can lead to a processing error.This description refers to the light sectioning method in which a line beam is emitted obliquely; however, the technique of the present embodiment is also applicable to a triangulation method in which a point light is used, an interference method, or the like, as in the method in which light is emitted obliquely.

[0103] Fig. Figure 24 is a flowchart illustrating the machining position search process of the additive manufacturing device 100 according to the second embodiment of the present invention. The machining position search process is described with reference to Fig. 25 to Fig. 33 described.

[0104] First, the additive manufacturing device 100 moves the drive platform 6 into the position for measuring the height at the machining position and begins measuring the height. Fig. Figure 25 is a diagram showing the positional relationship between the measuring illumination unit 8 and a bead before the start of the process. Fig. Figure 24 shows that in this example, the actual height T2 of object 4 is greater than the target height T0. If the height T2 differs from the target height T0, then (processing position CL) = (measuring position CH) does not hold, and the amount of the displacement of measuring position CH from processing position CL is ΔX2.

[0105] Fig. 26 is a diagram showing the light-receiving position on the light-receiving element in the Fig. Figure 25 shows the state depicted. Corresponding to the magnitude of the displacement ΔX2 of the illumination light 40, which is a line ray, a magnitude of displacement ΔX2' of the light-receiving position relative to the reference pixel position in the X-direction is generated. ΔX2' = M × ΔX2.

[0106] Now, the focus is shifting back to... Fig. 24 Referenced. The machining position search unit of the control unit 51 moves the drive platform 6 to reduce the height in the Z direction by a specific amount (step S301). Since the drive platform 6 is moved, the reduction in height in the Z direction is achieved by raising the drive platform 6 in the Z direction. The amount of the reduction in height is the lower limit of the height measurement range, which is determined by the number of pixels of the in Fig. The amount of reduction is determined by the light-receiving element shown in section 16. This reduction can be freely adjusted according to the height range of the spherical bead being measured.

[0107] Fig. Figure 27 is a diagram showing the positional relationship between the measuring illumination unit 8 and the workpiece 3 after step S301 of Fig. Figure 24 shows the movement of the drive platform 6 from the in Fig. In the state shown in Figure 25, the height of the measuring illumination unit 8 relative to the workpiece 3 decreases from H0 to H1. The amount of the reduction H0-H1 is half the height measuring range: Zr / 2=N×tanθ / M / 2. Fig. 28 is a diagram showing the light-receiving position on the light-receiving element in the Fig. The depicted state is shown in 27.

[0108] Now, the focus is shifting back to... Fig. 24 Referenced. The machining position search unit of the control unit 51 increases the height in the Z direction (step S302). Fig. Figure 29 is a diagram showing the positional relationship between the measuring illumination unit 8 and the workpiece 3 after step S302 of Fig. Figure 24 shows the movement of the drive platform 6 from the in Fig. The state shown in Figure 27 increases the height of the measuring illumination unit 8 relative to the workpiece 3 from H1 to H2. Fig. 30 is a diagram showing the light-receiving position on the light-receiving element in the Fig. The condition shown in section 29 is depicted. As in Fig. Figure 30 shows that when the height of the measuring illumination unit 8 is increased relative to the workpiece 3, the light receiving position of the illumination light 40 on the light-receiving element is moved in the +X direction.

[0109] Although a method for reducing and subsequently increasing the height of the measuring illumination unit 8 relative to the workpiece 3 has been described here, the height of the measuring illumination unit 8 relative to the workpiece 3 can be increased and subsequently decreased.

[0110] Now, the focus is shifting back to... Fig. 24 Referenced. The processing position search unit of the control unit 51 determines whether the light receiving position of the illumination light 40 reflected by the object 4 lies within a predetermined area on the light receiving element at the processing position (step S303).

[0111] Fig. 31 is a diagram showing a predetermined area L, which is defined in step S303 of Fig. 24 is used. The area L is a range that depends on the accuracy of the height of object 4 to be measured with respect to the reference pixel position. For example, the amount of the height shift ΔZ' per pixel can be determined using the formula ΔZ'=Ptanθ / M.

[0112] Now, the focus is shifting back to... Fig. 24. If it is determined that the light-receiving position of the illumination light 40 is within the predetermined range L (step S303: yes), the machining position search unit of the control unit 51 stops the drive platform 6 (step S304). If it is determined that the light-receiving position of the illumination light 40 is not within the predetermined range L (step S303: no), the machining position search unit of the control unit 51 returns to step S302.

[0113] Fig. 32 is a diagram in which the drive platform 6 is shown in step S304 of Fig. 24 was stopped. When the light receiving position enters the area L, as is the case in Fig. As shown in Figure 31, the drive platform 6 is stopped when the height of the measuring lighting unit 8 relative to the workpiece 3 is as shown in Figure 31. Fig. 32 is shown as H3.

[0114] Fig. 33 is a diagram comparing the state before the process of Fig. 24 and the state after step S304. H0 in Fig. Figure 33 shows the height of the measuring illumination unit 8 relative to the workpiece 3 before the process of Fig. 24 on. H3 in Fig. Figure 33 shows the height of the measuring illumination unit 8 relative to the workpiece 3 after step S304 of Fig. 24 on.

[0115] The height measuring unit calculates the difference H3-H0 between the heights H3 and H0, i.e., the difference in height of the drive platform 6 (step S305). Consequently, the difference in height of object 4 from the target height can be determined as T2-T0=H3-H0.

[0116] As described above, the processing position search unit enables the measurement of the height of object 4 at the processing position, even if the light section method, in which a line beam is emitted obliquely, results in a shift of the measuring position from the processing position due to a change in the height of object 4. Third embodiment.

[0117] Fig. Figure 34 is a diagram showing a configuration of an additive manufacturing device 101 according to the third embodiment of the present invention. The additive manufacturing device 101 differs from the additive manufacturing device 100 according to the first embodiment in the arrangement of the measuring illumination unit 8 and the imaging system. The third embodiment differs from the first embodiment in aspects that are mainly described below, omitting a description of similarities to the first embodiment.

[0118] In the additive manufacturing device 101, the measuring illumination unit 8 projects the illumination light 40, which is a line beam, parallel to the optical axis of the processing light 30. The light-receiving unit 17 receives the reflected light, which is reflected in an oblique direction. This prevents the measuring position of the line beam from being displaced, as described in the second embodiment; therefore, the height of the object 4 can be measured with high accuracy without the processing position search process.

[0119] In the device for additive manufacturing 101, the measuring illumination unit 8 is integrated into the processing head 2, and the light-receiving unit 17, which includes the light-receiving optical system and the light-receiving element, is attached to a side surface of the processing head 2.

[0120] Fig. 35 is a diagram that shows the internal configuration of the Fig. 34 shows the machining head 2. Fig. Figure 35 shows an XZ cross-section of the additive manufacturing device 101. The processing head 2 includes the light-projecting lens 11, the beam splitter 12, the objective lens 13, a beam splitter 22, and the measuring illumination unit 8. Since the processing optics system is the same as that of the first embodiment, a detailed description of it is omitted.

[0121] The illumination 40 emitted from the measuring illumination unit 8 is reflected by the beam splitter 22 through the objective lens 13 onto the processing position on the object 4, i.e., the measuring position. To allow light to pass through the objective lens 13 for processing, the measuring illumination unit 8 emits a beam that is concentrated onto the object 4 by the objective lens 13. As in the first embodiment, the illumination 40 need not necessarily be a line beam, but can be a point beam concentrated into a point shape.

[0122] The light-receiving unit 17 includes the converging lens 15 and the light receiver 16. Preferably, the light-receiving unit 17 also includes the bandpass filter 14, which selectively transmits the irradiation wavelength of the illumination light 40.

[0123] Fig. 36 is a diagram to explain the measurement of altitude in the Fig. 34 device for additive manufacturing 101. Fig. Figure 36(a) shows a spherical bead produced with the target height T1. Fig. Figure 36(b) shows a spherical bead produced with a height greater than the target height T1. Fig. Figure 36(c) shows a spherical bead produced with a height less than the target height T1. The illumination light 40 is emitted coaxially with the processing light 30. The measuring position CH therefore coincides with the processing position CL.

[0124] Fig. 37 is a diagram showing the light reception position of the light emitted from the Fig. 36(a) is reflected in the bead shown. In the case of carrying out the additive processing of the second layer on the spherical bead produced with the target height T1, which is in Fig. As shown in Figure 36(a), the processing head 2 is raised by T1; therefore, the light receiving position in the Y direction, which corresponds to the processing position on the light receiving element of the light receiver 16, is the reference pixel position.

[0125] Fig. 38 is a diagram showing the light reception position of the light emitted from the Fig. The pearl shown in 36(b) is reflected. In the case of the pearl shown in Fig. The spherical bead shown in Figure 36(b), formed with a height T2 greater than the target height T1, causes the processing head 2 to be raised by T1, shifting the light-receiving position on the light-receiving element in the Y direction from the reference pixel position by ΔX2'. Using the value of ΔX2' and the triangulation principle, T2-T1 can be calculated.

[0126] Fig. 39 is a diagram showing the light reception position of the light emitted from the Fig. The pearl depicted in 36(c) is reflected. In the case of the pearl shown in Fig. The spherical bead shown in Figure 36(c), formed with a height T3 that is less than the target height T1, causes the processing head 2 to be raised by T1, shifting the light-receiving position on the light-receiving element in the Y direction from the reference pixel position by ΔX3'. Using the value of ΔX3' and the triangulation principle, T1-T3 can be calculated.

[0127] As described above, the additive manufacturing device 101, according to the present embodiment, projects the illumination light 40 for height measurement parallel to the optical axis of the processing light 30 and includes the light-receiving unit 17, which is positioned at an angle relative to the optical axis. This configuration makes it possible to maintain the measurement position of the illumination light 40 independently of changes in the height of the spherical beads at the processing position. Thus, the height of the processing position can be measured with high accuracy, independent of the height of the object 4.

[0128] Fig. 40 is a diagram that is a modification of the in Fig. The device for additive manufacturing 101 shown in Figure 35 is illustrated. The present embodiment is not limited to the exemplary configuration of Fig. 35 limited, in which the measuring illumination unit 8 is integrated into the processing head 2. As in Fig. As shown in Figure 40, the measuring illumination unit 8 and the processing head 2 can be separated from each other. In this case, there is a difference ΔD between the optical axis of the illumination light 40 emitted by the measuring illumination unit 8 and the optical axis of the processing light 30. For height measurement, the drive platform 6 is therefore moved by the difference ΔD between the processing position and the measuring position, allowing the height of the object 4 at the processing position to be measured with high accuracy.

[0129] The configurations described in the embodiments mentioned above show examples of the content of the present invention. These configurations can be combined with other well-known techniques, and some of the configurations can be omitted or modified to an extent that does not deviate from the essence of the present invention. Reference symbol list 1 processing laser; 2 processing head; 3 workpieces; 4. Item; 5 brackets; 6 Drive platform; 7 Processing material; 8 measuring lighting units; 9 Gas nozzle; 10 processing material feed unit; 11 light-projecting lens; 12 beam splitters; 13 Objective lens; 14 bandpass filters; 15 Converging lens; 16 light receivers; 17 light-receiving units; 20 lower limit; 21 upper limit; 30 processing lights; 40 lighting lights; 50 units of calculation; 51 Control unit; 71 drops; 72 Melt residue; 100 Device for additive manufacturing; 190 processing circuits; 200 control circuit; 200a processor; 200b of storage. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2016179501 ​​

[0004]

Claims

[1] Device for additive manufacturing for forming an object by repeated additive processing by melting a processing material and applying the solidified processing material to a workpiece, wherein the device for additive manufacturing comprises: a height measuring unit that measures the height of the object being formed at a processing position; and a control unit that controls a processing condition for applying the processing material at the processing position based on a measurement result provided by the height measuring unit. [2] Device for additive manufacturing according to claim 1, wherein the control unit controls the processing condition such that the processing material to be applied at the processing position has a height which is equal to a difference between a target height and the measurement result. [3] Device for additive manufacturing according to claim 1 or 2, wherein The height measuring unit measures the height of the object at a first machining position before the additive machining is performed at the first machining position, and The control unit controls the processing conditions in such a way that the object has a target height at the first processing position after additive processing. [4] Device for additive manufacturing according to any one of claims 1 to 3, wherein the additive manufacturing process comprises: a first process of melting the processing material supplied to the first processing position and a second process of moving a processing material supply position to a second processing position which differs from the first processing position, wherein the second process is carried out after the first process. [5] Device for additive manufacturing according to one of claims 1 to 4, wherein the movement from the first processing position to the second processing position, which is a processing position next to the first processing position, comprises a movement in a direction orthogonal to a height direction of the object. [6] Device for additive manufacturing according to any one of claims 1 to 5, wherein at least a part of the object is produced using a bead formed from the processing material melted at a processing position. [7] Device for additive manufacturing according to any one of claims 1 to 6, wherein the height measuring unit comprises: a measuring illumination unit for illuminating a measuring position with measuring illumination light; and a light receiver for receiving reflected light, which is the measuring illumination light reflected at the measuring position, and wherein the height measuring unit calculates the height of the object formed on the workpiece on the basis of a light receiving position of the reflected light on the light receiver. [8] Device for additive manufacturing according to claim 7, wherein The height measuring unit includes a light reception optical system for concentrating the reflected light onto the light receiver, and The light reception optics system is integrated with a processing optics system to focus processing light on a processing position for melting the processing material. [9] Device for additive manufacturing according to claim 7 or 8, wherein the measuring position is located within a field of view of a light-receiving element of the light receiver. [10] Device for additive manufacturing according to one of claims 7 to 9, wherein the measuring illumination light is a linearly emitted line beam. [11] Device for additive manufacturing according to any one of claims 1 to 7, comprising a processing optics system for focusing processing light to melt the processing material onto a processing position. [12] Device for additive manufacturing according to any one of claims 1 to 11, wherein the control unit reduces the quantity of the material supplied to a machining position when the measurement result is higher than a predetermined target height, and increases the quantity of the supply when the measurement result is lower than the target height. [13] Device for additive manufacturing according to one of claims 7 to 10, wherein the control unit reduces the output power of the processing light for melting the processing material when the measurement result is higher than a predetermined target height, and increases the output power of the processing light when the measurement result is lower than the target height. [14] Device for additive manufacturing according to one of claims 7 to 10, wherein the control unit reduces the duration of the emission of the processing light for melting the processing material when the measurement result is higher than a predetermined target height, and increases the duration of the emission of the processing light when the measurement result is lower than the target height. [15] Device for additive manufacturing according to any one of claims 1 to 14, wherein the control unit reduces the number of times a deposition is produced at the processing position when the measurement result is higher than a predetermined target height, and increases the number of times a deposition is produced at the processing position when the measurement result is lower than the target height. [16] Device for additive manufacturing according to any one of claims 1 to 14, wherein the control unit increases the height of an end of the material being processed in accordance with a predetermined target height, and wherein the control unit increases the amount of the increase in the height of the end before melting if the measurement result is higher than the target height, and decreases the amount of the increase in the height of the end before melting if the measurement result is lower than the target height. [17] Device for additive manufacturing according to claim 7, wherein the control unit changes the height of the measuring lighting unit relative to the workpiece, and The height measuring unit measures the height of the object formed at the machining position based on the light reception position obtained while the height of the measuring illumination unit is changed relative to the workpiece. [18] Device for additive manufacturing according to claim 7, wherein an optical axis of the measuring illumination light is parallel to an optical axis of the processing light. [19] Additive manufacturing method for forming an object on a workpiece by repeated additive processing by melting a processing material and applying the solidified processing material to the workpiece, wherein the additive manufacturing method comprises: a step in which an additive manufacturing device measures the height of the object being formed at a machining position; and a step in which the additive manufacturing device controls a machining condition for applying the machining material at the machining position based on a result of measuring the height of the formed object. [20] Additive manufacturing program to cause a computer to perform an additive manufacturing process in which an object is formed on a workpiece by repeated additive processing by melting a processing material and applying the solidified processing material to the workpiece, wherein the additive manufacturing process comprises: a step in which the height of the object formed at a machining position on the workpiece is measured; and a step in which a processing condition for applying the processing material to the processing position is controlled based on a result of measuring the height of the formed object.

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