Additive Manufacturing Equipment

Abstract

To provide an additive manufacturing apparatus capable of suppressing an effect of heat storage associated with a formation of bead, and to provide an additive manufacturing apparatus capable of additively manufacturing a high-quality additive manufactured product.SOLUTION: A controller of an additive manufacturing apparatus determines a position away from a heat storage range SR generated on a molding surface B1 of a base material B by storing heat from at least a heat-retaining light beam irradiated in a previous bead N1 formation as a formation position BB to form this time bead N2.SELECTED DRAWING: Figure 12

Description

[Technical Field]

[0001] The present invention relates to additive manufacturing devices. [Background technology]

[0002] Known additive manufacturing methods include, for example, Directed Energy Deposition (DED) and Powder Bed Fusion (PBF). Directed energy deposition (DED) performs additive manufacturing by controlling the position of a processing head that irradiates a light beam (such as a laser beam or electron beam) and supplies material. Directed energy deposition methods include LMD (Laser Metal Deposition) and DMP (Direct Metal Printing). Powder bed fusion (PBF) performs additive manufacturing by irradiating a light beam onto a flatly spread powder material. Powder bed fusion methods include SLM (Selective Laser Melting) and EBM (Electron Beam Melting).

[0003] For example, LMD, a directed energy deposition method, sprays powdered material containing hard materials while irradiating it with a light beam, melting the powdered material and then solidifying it. This allows LMD to be used as a build-up technology that partially adds hard material additives to a substrate.

[0004] For example, Patent Document 1 discloses an additive manufacturing device that forms multiple beads on a substrate. In conventional additive manufacturing devices, a current bead is formed adjacent to a previously formed bead. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-124722 Summary of the Invention [Problem to be solved by the invention]

[0006] In conventional additive manufacturing devices, when multiple beads are formed, each bead is formed adjacent to or in contact with a previously formed bead. When forming a bead, a light beam is irradiated to form a molten pool in which the supplied powder material and a portion of the substrate are melted. In this state, the temperature of the substrate near the formed bead becomes higher than that of the portion where no bead is formed due to the accumulation of energy, i.e., heat, from the irradiated light beam.

[0007] Therefore, when a current bead is formed adjacent to a previously formed bead, the temperature of the substrate at the formation position where the current bead is formed is high, so excessive energy is supplied to form the molten pool. As a result, the molten pool expands excessively, causing dilution of the powder material components (hard materials, etc.) in the molten pool, which may affect the strength of the bead, i.e., the additive product. Therefore, at the formation position where the current bead is formed, it is necessary to suppress the influence of heat accumulation caused by the formation of the previous bead and prevent excessive energy from being supplied.

[0008] The present invention aims to provide an additive manufacturing device that can suppress the effects of heat accumulation associated with bead formation and can additively manufacture high-quality additive products. [Means for solving the problem]

[0009] One aspect of the present invention is a powder material supplying device that supplies a powder material including a hard material and an ultra-hard binder to a substrate; The substrate The shape of and the substrate The shaping surface of The powder material supplied to the substrate The shaping surface of and a melting light beam that heats the powder material to a temperature above its melting point and melts it. , in a predetermined melting light irradiation rangea melting light beam irradiation device for irradiating the melting light beam; The position where the melting light irradiation area is overlapped and the Melting light irradiation range In a predetermined heat-retaining light irradiation range that surrounds at least the rear position in the scanning direction, a heat-keeping light beam irradiating device that irradiates a heat-keeping light beam that heats the material to a temperature below the melting point and keeps it warm; Irradiation of the melting light beam and the heat-keeping light beam, and the substrate The shaping surface of a control device that independently controls each of the melting light beam irradiating device and the heat-keeping light beam irradiating device with respect to the relative scanning of the melting light beam and the heat-keeping light beam with respect to the object; The substrate The shaping surface of An additive manufacturing apparatus that additively manufactures an additive product by forming a plurality of beads on a substrate, The control device Irradiation following the previous formation of the bead was the heat-preserving light beam The temperature rose due to The substrate The range of the molding surface is defined as a heat storage range, A position away from the heat accumulation area is determined as the formation position for forming the bead this time. 、 Or, The additive manufacturing device defines the heat-retaining light irradiation range of the heat-retaining light beam irradiated in conjunction with the formation of the previous bead as a heat storage range, and determines the formation position of the current bead so that the heat-retaining light irradiation range of the heat-retaining light beam irradiated in conjunction with the formation of the current bead does not overlap with the heat storage range.

[0010] According to this, the control device can determine, as the formation position for forming the current bead, a position away from the heat accumulation area generated in the substrate by the heat generated by irradiating the substrate with at least the heat-retaining light beam during the formation of the previous bead. This makes it possible to prevent excessive energy from being supplied to the substrate by the melting light beam and the heat-retaining light beam when forming the current bead, and as a result, to prevent excessive expansion of the molten pool that forms the current bead. Therefore, the additive manufacturing device can additively manufacture high-quality additive products. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 illustrates an additive manufacturing device. [Figure 2]FIG. 2 is a diagram for explaining a movement device of the additive manufacturing apparatus of FIG. 1. [Figure 3] 10A and 10B are diagrams for explaining a melting light irradiation range of a melting light beam and a heat-keeping light irradiation range of a heat-keeping light beam. [Figure 4] 2 is a beam profile showing the relationship between power density and light irradiation range when additively manufacturing an additive product on a substrate using the additive manufacturing device of FIG. 1. [Figure 5] 2 is a cross-sectional view showing the initial state of an additive product added to a substrate when additively manufacturing an additive product using the additive manufacturing device of FIG. 1. FIG. [Figure 6] 6A to 6C are cross-sectional views showing the intermediate state and added state of an additive product additively manufactured on a substrate when scanning has progressed from the state of FIG. 5. [Figure 7] FIG. 10 is a diagram for explaining a heat accumulation range that occurs with the formation of a bead. [Figure 8] 10A and 10B are diagrams for explaining the expansion of the heat accumulation area and the expansion of the molten pool when adjacent beads are formed. [Figure 9] FIG. 10 is a diagram for explaining a position where a bead is formed. [Figure 10] 10 is a flowchart of an additive manufacturing device control program. [Figure 11] FIG. 10 is a diagram illustrating a state in which the first bead is formed. [Figure 12] 12 is a diagram for explaining a state in which the substrate in FIG. 11 has been rotated a quarter of its circumference and the next bead has been formed. FIG. [Figure 13] 13 is a diagram for explaining a state in which the substrate in FIG. 12 has been rotated a quarter of its circumference and the next bead has been formed. FIG. [Figure 14] FIG. 10 is a diagram illustrating a case where a bead is formed in a spiral shape according to a first modified example. [Figure 15] FIG. 10 is a diagram illustrating a second modification of the method for forming a bead on a substrate having a flat surface. DETAILED DESCRIPTION OF THE INVENTION

[0012] (1. Overview of additive manufacturing equipment) The additive manufacturing apparatus of this example employs, for example, a directed energy deposition (LMD) method. In this example, the additive manufacturing apparatus additively manufactures a hard additive product on a substrate by spraying a powder material, which is a mixture of a hard powder material and a binder powder material, toward the substrate while irradiating the substrate with a light beam. The powder materials, particularly the hard powder material and the substrate, may be different materials or the same type of material. Furthermore, the powder material may be a granulated powder formed by solidifying a hard powder material and a binder powder material.

[0013] In this example, we will describe additive manufacturing of a hard additively manufactured product formed using a hard powder material of tungsten carbide (WC) on a substrate made of carbon steel (S45C). It should be noted that other hard materials that may crack during additive manufacturing, such as high-speed steel, may also be used as the hard material. It should be noted that it is also possible to use an iron-based material, such as carbon steel, whose hardness changes depending on the temperature, as the powder material.

[0014] In this example, the binding powder material is cobalt (Co), which acts as an ultra-hard binder that binds tungsten carbide (WC). The melting point (solidification point) of tungsten carbide (WC) is 2870°C, which is higher than the melting point (solidification point) of the ultra-hard binder cobalt (Co), which is 1495°C. In this example, cobalt (Co) is used as the hard binder. However, the hard binder is not limited to cobalt (Co), and for example, nickel (Ni) can also be used as the hard binder.

[0015] 2. Configuration of Additive Manufacturing Apparatus 100 1, the additive manufacturing apparatus 100 mainly includes a powder material supply device 110, a light beam irradiation device 120, and a control device 130. The basic structure and operation of the additive manufacturing apparatus 100 of this example are the same as those of well-known LMD-type additive manufacturing apparatuses. Therefore, a detailed description of the configuration, operation, etc. of the additive manufacturing apparatus 100 will be omitted.

[0016] The powder material supply device 110 includes a hopper 111, a valve 112, a gas cylinder 113, and an injection nozzle 114. The hopper 111 stores a hard powder material P1 mixed with a binding powder material P2. In the following description, the powder material mixed with the hard powder material P1 and the binding powder material P2 will be simply referred to as "powder material P."

[0017] The valve 112 includes a powder introduction valve 112a, a powder supply valve 112b, and a gas introduction valve 112c. The powder introduction valve 112a is connected to the hopper 111 via a pipe 111a. The powder supply valve 112b is connected to the injection nozzle 114 via a pipe 114a. The gas introduction valve 112c is connected to a gas cylinder 113 via a pipe 113a.

[0018] The injection nozzle 114 and the pipe 114a are housed in a cylindrical container 115 having a sloped portion on the injection nozzle 114 side. The injection nozzle 114 is disposed at the tip of the sloped portion of the container 115. The injection nozzle 114 then injects the powder material P toward the substrate B, more specifically, toward the manufacturing surface B1 on which the additive product FF is to be manufactured, via the pipe 114a, using high-pressure nitrogen supplied from a gas cylinder 113, for example. Note that the gas used to inject the powder material P is not limited to nitrogen, and may be an inert gas such as argon.

[0019] The light beam irradiation device 120 includes a melting light beam irradiation device 121 and a heat-keeping light beam irradiation device 122. The light beam irradiation device 120 also includes a moving device 123 that moves the melting light beam irradiation device 121 and the heat-keeping light beam irradiation device 122 independently relative to each other, or moves the melting light beam irradiation device 121 and the heat-keeping light beam irradiation device 122 together. Here, as shown in Figures 1 and 2, the melting light beam irradiation device 121 and the heat-keeping light beam irradiation device 122 are arranged by the moving device 123 so that the irradiation directions (optical axes) of the light beams irradiated by each of them intersect or have a twisted positional relationship.

[0020] 3, the melting light beam irradiating device 121 and the heat-maintaining light beam irradiating device 122 are arranged so that the irradiation range of the melting light beam MBM by the melting light beam irradiating device 121 and the irradiation range of the heat-maintaining light beam KBM by the heat-maintaining light beam irradiating device 122 overlap (overlap). Hereinafter, the irradiation range of the melting light beam MBM by the melting light beam irradiating device 121 will be referred to as the melting light irradiation range MS heated by the melting light beam MBM, and the irradiation range of the heat-maintaining light beam KBM by the heat-maintaining light beam irradiating device 122 will be referred to as the heat-maintaining light irradiation range KS kept warm (preheated or heated) by the heat-maintaining light beam KBM.

[0021] The melting light beam irradiation device 121 includes a melting light beam irradiation unit 121b that irradiates the melting light beam MBM generated and supplied by the melting light beam generation unit 121a perpendicularly to the forming surface B1 of the substrate B. The melting light beam generation unit 121a is controlled by the control device 130 to generate the melting light beam MBM.

[0022] The melting light beam irradiating unit 121b is disposed in the vicinity of the spray nozzle 114 inside the container 115. Specifically, the melting light beam irradiating unit 121b is disposed at the tip of the inclined portion of the container 115 so that the melting light beam MBM can be irradiated toward the supply position of the powder material P sprayed from the spray nozzle 114, in other words, so that the powder material P sprayed from the spray nozzle 114 toward the melting light irradiation range MS and the manufacturing surface B1 (substrate B) can be heated.

[0023] The melting light beam MBM is irradiated through an optical system including a collimator lens and a condenser lens (not shown) arranged inside the container 115. As shown in FIG. 1, the melting light beam MBM melts the powder material P supplied from the powder material supply device 110 on the building surface B1 (substrate B) to form a molten pool MP. The "processing head" is composed of the injection nozzle 114, the melting light beam irradiation device 121, and the container 115. As a result, the powder material P and the melting light beam MBM move together, so that the powder material P is injected into the melting light irradiation range MS irradiated by the melting light beam MBM.

[0024] The heat-keeping light beam irradiator 122 includes a heat-keeping light beam irradiator 122b that irradiates the heat-keeping light beam KBM generated and supplied by the heat-keeping light beam generator 122a onto the printing surface B1 of the substrate B. The heat-keeping light beam irradiator 122 is disposed so that the irradiation direction (optical axis) of the heat-keeping light beam KBM is inclined with respect to the irradiation direction (optical axis) of the melting light beam MBM from the heat-keeping light beam irradiator 121. The heat-keeping light beam irradiator 122 irradiates the printing surface B1 (substrate B) of Heat (or preheat) and keep warm.

[0025] The heat-keeping light beam generating unit 122a is controlled by the control device 130 to generate the heat-keeping light beam KBM. The heat-keeping light beam irradiating unit 122b is arranged at the tip of the cylindrical container 122c, facing the substrate B (printing surface B1). Specifically, the heat-keeping light beam irradiating unit 122b is arranged at the tip of the container 122c so that the heat-keeping light beam KBM can be irradiated such that the heat-keeping light irradiation range KS overlaps the melting light irradiation range MS of the melting light beam MBM irradiated from the melting light beam irradiating device 121. Furthermore, the heat-keeping light beam irradiating unit 122b is arranged at the tip of the container 122c so that the heat-keeping light beam KBM can be irradiated toward the front and rear, particularly at least the rear, of the formed molten pool MP in the scanning direction of the melting light beam irradiating device 121.

[0026] The heat-keeping light beam KBM is irradiated through an optical system such as a collimator lens and a condenser lens (not shown) arranged inside the container 122c. The heat-keeping light beam KBM is irradiated onto the forming surface B1 of the base material B within the heat-keeping light irradiation range KS. of The molten pool MP formed by the melting light beam MBM is preheated (heated) and kept warm.

[0027] 2, the moving device 123 mainly includes a first robot arm 123a and a second robot arm 123b. The first robot arm 123a supports the melting light beam irradiating device 121 (i.e., the processing head). The first robot arm 123a relatively displaces the melting light beam irradiating device 121 in a state in which the irradiation direction of the melting light beam MBM (i.e., the optical axis of the melting light beam MBM) is perpendicular to the forming surface B1 of the base material B.

[0028] The second robot arm 123b supports the heat-keeping light beam irradiator 122. Specifically, the second robot arm 123b supports the heat-keeping light beam irradiator 122 in a position where the irradiation direction of the heat-keeping light beam KBM (i.e., the optical axis of the heat-keeping light beam KBM) is tilted relative to the irradiation direction of the melting light beam MBM (the optical axis of the melting light beam MBM), in other words, in a position where the irradiation direction of the heat-keeping light beam KBM (the optical axis of the heat-keeping light beam KBM) is tilted relative to the printing surface B1. The second robot arm 123b in this example displaces the heat-keeping light beam irradiator 122 relative to the substrate B, following the melting light beam irradiator 121.

[0029] 3, the melting light beam irradiator 121 irradiates a melting light beam MBM having a circular irradiation shape. The heat-keeping light beam irradiator 122 irradiates a heat-keeping light beam KBM having a rectangular irradiation shape that overlaps with the melting light irradiation range MS of the melting light beam MBM and surrounds the outside of the melting light irradiation range MS of the melting light beam MBM (i.e., includes the melting light irradiation range MS within). That is, the heat-keeping light irradiation range KS over which the heat-keeping light beam irradiator 122 irradiates the heat-keeping light beam KBM is wider than the melting light irradiation range MS over which the melting light beam irradiator 121 irradiates the melting light beam MBM.

[0030] As a result, the melting light beam MBM irradiated to the melting light irradiation area MS mainly melts the powder material P on the building surface B1 of the base material B, thereby additively manufacturing an additive product FF consisting of multiple beads N, as shown in Figure 1. Also, the heat-retaining light beam KBM irradiated to the heat-retaining light irradiation area KS mainly preheats the building surface B1 of the base material B. Also, the heat-retaining light beam KBM irradiated to the heat-retaining light irradiation area KS mainly keeps the additive product FF (more specifically, the molten pool MP in which the powder material P is melted) additively manufactured on the building surface B1 of the base material B warm so as to suppress a drop in temperature.

[0031] In this example, laser light is used as the melting light beam MBM and the heat-retaining light beam KBM. However, the melting light beam MBM and the heat-retaining light beam KBM are not limited to laser light, and any electromagnetic wave, such as an electron beam, can also be used. Also, in this example, a square-shaped heat-retaining light beam KBM (i.e., heat-retaining light irradiation area KS) is irradiated so as to overlap with a circular melting light beam MBM (i.e., melting light irradiation area MS), but the irradiation shape is not limited to this.

[0032] The control device 130 is a computer device whose main components include a CPU, ROM, RAM, an interface, etc. The control device 130 controls the powder supply of the powder material supply device 110. Specifically, the control device 130 controls the opening and closing of the powder supply valve 112b and the gas introduction valve 112c, thereby controlling the injection supply of the powder material P from the injection nozzle 114 toward the building surface B1 of the substrate B.

[0033] Furthermore, the control device 130 controls the light irradiation of the light beam irradiation device 120, i.e., the melting light beam irradiation device 121, the heat-keeping light beam irradiation device 122, and the moving device 123. Specifically, the control device 130 controls the operation of the melting light beam generator 121a of the melting light beam irradiation device 121 and the heat-keeping light beam generator 122a of the heat-keeping light beam irradiation device 122. In this way, the control device 130 independently controls the output conditions of the melting light beam MBM and the heat-keeping light beam KBM. Here, examples of the output conditions include the respective laser outputs and, as shown in FIG. 4, the distribution shape of the power density, i.e., the beam profile, which is the laser output (W) per unit area of ​​the melting light irradiation range MS, which is the irradiation range of the melting light beam MBM, and the heat-keeping light irradiation range KS, which is the irradiation range of the heat-keeping light beam KBM.

[0034] Here, the control device 130 controls the melting light beam MBM so that the peak MBP1 in the beam profile of the power density is increased from the peak KBP1 in the beam profile of the power density of the heat-retaining light beam KBM, as shown in Fig. 4. The laser output of the melting light beam MBM is controlled to a temperature that can melt the hard powder material P1 and the binder powder material P2 to form a molten pool MP. In addition, the laser output of the heat-retaining light beam KBM is controlled to a temperature that does not melt the hard powder material P1, the binder powder material P2, and the substrate B (the build surface B1).

[0035] Furthermore, the control device 130 operates the first robot arm 123a and the second robot arm 123b of the moving device 123 to make the heat-keeping light beam KBM follow the movement (trajectory) of the melting light beam MBM. Furthermore, the control device 130 controls the relative scanning of the melting light beam MBM and the heat-keeping light beam KBM with respect to the forming surface B1 of the substrate B. Specifically, in this example, the control device 130 controls the rotation of the motor M1 to rotate the substrate B around the central axis C, and controls the rotation of the motor M2 to move the substrate B in the direction of the central axis C. In this way, the control device 130 controls the relative scanning of the melting light beam MBM and the heat-keeping light beam KBM with respect to the peripheral surface of the substrate B.

[0036] In this example, the control device 130 rotates and moves the base material B. However, it goes without saying that the control device 130 can control the moving device 123 to move the melting light beam irradiating device 121 and the heat-retaining light beam irradiating device 122 relative to the forming surface B1 of the base material B.

[0037] (3. Overview of additive manufacturing method for additive products FF) Next, we will explain the additive manufacturing method of the additive product FF (bead N). In the additive manufacturing method of the additive product FF (bead N), a heat-retaining light beam KBM is irradiated to perform preheating, which is a pre-treatment in the additive manufacturing process of the additive product FF (bead N), and heat-retaining, which is a post-treatment, in the heat-retaining light irradiation range KS.

[0038] Generally, when the temperature of the building surface B1 of the base material B is low, the thermal energy caused by the irradiation of the melting light beam MBM is likely to escape to the base material B. As a result, when additively manufacturing an additive product FF (bead N) on the building surface B1 of the base material B using the melting light beam MBM, this can easily lead to poor melting, such as insufficient melting, so the building surface B1 of the base material B is preheated (heated) using the heat-retaining light beam KBM.

[0039] At this time, the heat-retaining light beam KBM in the preheating process irradiates a heat-retaining light irradiation range KS in front of the scanning direction SD of the melting light beam MBM so as to overlap with the melting light irradiation range MS of the melting light beam MBM (intersect with the optical axis of the melting light beam MBM), as shown in Figure 5. In this way, the heat-retaining light beam KBM preheats the building surface B1 of the base material B on which the additive product FF (bead N) is formed. Note that the laser output of the heat-retaining light beam KBM in the preheating process is controlled so that the building surface B1 of the base material B is maintained at a predetermined temperature without melting.

[0040] Furthermore, if the additive product FF (bead N) is cooled rapidly after it is formed, cracks or the like are likely to occur in the additive product FF (bead N). For this reason, after the additive product FF (bead N) is formed (shaped) using the melting light beam MBM, the heat-retaining light beam KBM is used to keep the shaping surface B1 of the substrate B, i.e., the additive product FF (bead N), warm (heat).

[0041] At this time, the heat-retaining light beam KBM in the heat-retaining process is irradiated up to a heat-retaining light irradiation range KS on the rear side of the scanning direction (SD) of the melting light beam MBM so as to overlap with the melting light irradiation range MS of the melting light beam MBM (intersect with the optical axis of the melting light beam MBM), as shown in Figure 5. In this way, the heat-retaining light beam KBM keeps the formed additive product FF (bead N) warm. Note that the laser output of the heat-retaining light beam KBM in the heat-retaining process is controlled so that the formed additive product FF (bead N) and the forming surface B1 of the substrate B do not melt and are cooled at a predetermined cooling rate (°C / s).

[0042] Furthermore, in the additive manufacturing method for the additive product FF (bead N), the melting light beam MBM is irradiated while the heat-retention light beam KBM is performing preheating and heat-retention processes, thereby performing a melting process in which a part of the building surface B1 of the base material B and the powder material P are melted in the melting light irradiation range MS to form a molten pool MP. As a result, the melting light beam MBM forms (builds) the additive product FF (bead N) on the building surface B1 of the base material B.

[0043] Specifically, in the additive manufacturing method, as shown in Figure 6, the melting light beam MBM is scanned in the scanning direction SD to expand the molten pool MP, thereby additively manufacturing an additive product FF (bead N). The melting light beam MBM melts the powder material P so as to expand the molten pool MP, and then moves sequentially in the scanning direction SD. Here, the additive product FF (bead N) in this example is formed by bonding tungsten carbide (WC) as the hard powder material P1 with cobalt (Co) as the bonding powder material P2, which acts as an ultrahard binder. The additive product FF in this example is composed of multiple beads N formed in stripes along the direction of the central axis C of the substrate B (see Figure 1).

[0044] However, when the temperature of the building surface B1 of the base material B rises and becomes high due to the continuous formation of multiple beads N adjacent to each other, the thermal energy caused by the irradiation of the melting light beam MBM tends to become excessive. As a result, when additively manufacturing an additive product FF (bead N) on the building surface B1 of the base material B in the melting process, if the molten pool MP expands too much due to excess energy, the bead width of the bead N may increase, the bead height may fluctuate, or the base material B may melt into the bead N (dilution), which can easily lead to additive manufacturing defects.

[0045] More specifically, on the building surface B1 of the substrate B, the temperature in the trajectory KH (see FIG. 3) of the heat-retaining light irradiation area KS, which is formed by the heat-retaining light beam KBM moving in accordance with the movement of the melting light beam MBM, gradually cools after the additive product FF is formed by the irradiation of the heat-retaining light beam KBM. As a result, as shown in FIG. 7, the area surrounding the heat-retaining light irradiation area KS becomes a heat storage area SR, which has been heated by storing heat from at least the heat-retaining light beam KBM irradiated in conjunction with the formation of the bead N, and the temperature is higher than that of the area on the building surface B1 of the substrate B away from the heat storage area SR. Here, in this example, as shown in FIG. 7, a case is illustrated in which the heat storage area SR is wider than the heat-retaining light irradiation area KS. However, if the heat storage area SR includes the heat-retaining light irradiation area KS, the heat storage area SR may coincide with the heat-retaining light irradiation area KS. In other words, in this case, the heat storage area SR becomes the heat-retaining light irradiation area KS.

[0046] Therefore, on the building surface B1 of the base material B, when a current additive product FF, i.e., bead N2, is formed adjacent to an additive product FF, i.e., bead N1, formed in a previous forming operation, as shown in Fig. 8, a heat accumulation area SR is formed at the formation position of the current bead N2, resulting in a high temperature. In a state where the heat accumulation area SR is formed due to the formation of the previous bead N1 and the temperature of the formation position where the bead N2 is formed is high, the melting of the base material B and the powder material P melted by the melting light beam MBM is excessively promoted. In other words, the expansion of the molten pool MP that forms the bead N2 is promoted.

[0047] Furthermore, when bead N3 is formed adjacent to bead N2, a heat accumulation range SR is formed due to the heat accumulation associated with the formation of bead N2 in addition to the heat accumulation associated with the formation of bead N1, and the temperature at the formation position where bead N3 is formed becomes higher than the temperature at the formation position where bead N2 is formed. As a result, the molten pool MP where bead N3 is formed is further promoted to expand. Therefore, the temperature at the formation position where bead N, i.e., additive product FF, is formed needs to be a temperature suitable for forming bead N (additive product FF) in order to eliminate defective factors in additive manufacturing.

[0048] Incidentally, for example, by providing a time interval between the formation of the previous bead N (additive product FF) and the start of the formation of the current bead N (additive product FF), it is possible to cool the formation position of the current bead N (additive product FF). However, in this case, the manufacturing time required for additive manufacturing of multiple beads N, i.e., additive products FF, becomes longer, and additive manufacturing efficiency (production efficiency) is impaired.

[0049] Therefore, in this example, when forming an additive product FF consisting of multiple beads N, as shown in Figure 9, bead N2 is formed on the building surface B1 of the substrate B at a formation position BB that is a position separated from the heat storage range SR that includes the formation position AB of the previous bead N1. That is, on the building surface B1 of the substrate B, bead N2 is formed at a formation position BB that is determined so that the heat-retaining light irradiation range KS of the heat-retaining light beam KBM irradiated in the formation of the current bead N2 does not overlap with the heat-retaining light irradiation range KS of the heat-retaining light beam KBM irradiated in the formation of the previous bead N1. Similarly, bead N3 is formed at a formation position CB that is a position separated from the heat storage range SR that includes the formation position BB of the previous bead N2.

[0050] Specifically, in this example, bead N2 is formed at a formation position BB that is 90 degrees away in the circumferential direction of the base material B from the heat storage area SR that includes the formation position AB of bead N1. Similarly, in this example, bead N3 is formed at a formation position CB that is 90 degrees away in the circumferential direction of the base material B from the heat storage area SR that includes the formation position BB of bead N2. That is, in this example, when the circumferential direction of the base material B is divided into four, each bead N is formed sequentially at a formation position that is separated by one-quarter of the circumference in the circumferential direction of the base material B from the heat storage area SR that was created at the previous formation position.

[0051] (4. Details of the manufacturing method of additive product FF) Next, details of the additive manufacturing method for the additive product FF will be described. The control device 130 starts execution of the additive manufacturing device control program shown in Fig. 10 in step S10, and in the subsequent step S11, the control device 130 indexes and determines the formation position of the current additive product FF, i.e., the bead N. That is, for example, when the previous bead N1 is formed at formation position AB as shown in Fig. 11, the control device 130 determines the formation position BB of the current bead N2 to be a position spaced apart by ¼ of the circumference (90 degrees) in the circumferential direction of the base material B from the heat accumulation range SR including the formation position AB, as shown in Fig. 12.

[0052] Accordingly, the control device 130 operates the motor M1 to rotate the substrate B by 90 degrees so that the forming position BB faces the melting light beam irradiating device 121 and the heat-retaining light beam irradiating device 122 supported by the first robot arm 123a and the second robot arm 123b of the moving device 123. Then, after determining the forming position BB and rotating the substrate B, the control device 130 executes the step processing of step S12.

[0053] In this example, the control device 130 drives the motor M1 to rotate the substrate B in accordance with the determined forming position BB. However, the control device 130 may also operate the first robot arm 123a and the second robot arm 123b of the moving device 123 in accordance with the determined forming position BB to move the melting light beam irradiating device 121 and the heat-retaining light beam irradiating device 122 toward the forming position BB.

[0054] In step S12, the control device 130 controls the operation of the powder material supply device 110 and the light beam irradiation device 120 to form an additive product FF, i.e., a bead N. That is, the control device 130 controls the opening and closing of the valve 112 of the powder material supply device 110, specifically, the powder supply valve 112b and the gas introduction valve 112c, and supplies a preset supply amount of powder material P from the injection nozzle 114 to a formation position BB on the building surface B1 of the substrate B, for example, as shown in FIG.

[0055] Furthermore, the control device 130 operates the melting light beam irradiation device 121 and the heat-retaining light beam irradiation device 122 of the light beam irradiation device 120 in accordance with the supply of powder material P from the powder material supply device 110. Then, the control device 130 irradiates the melting light beam MBM onto the powder material P supplied to the forming position BB, for example, in the melting light irradiation range MS, thereby melting a part of the building surface B1 of the base material B and the powder material P, i.e., forming a molten pool MP, and forming a bead N2 (melting process). As a result, the melting light beam irradiation device 121 forms a bead N2, i.e., an additive product FF, on the building surface B1 of the base material B, as shown in FIG.

[0056] 12, the control device 130 irradiates the bead N (additive product FF) formed on the building surface B1 of the base material B with a heat-retaining light beam KBM in the heat-retaining light irradiation range KS, thereby keeping the bead N2 (additive product FF) warm (heat-retaining process). As a result, the heat-retaining light beam irradiating device 122 prevents the bead N2 formed on the building surface B1 of the base material B, i.e., the additive product FF, from cracking due to rapid cooling. Then, once the control device 130 forms (builds) the bead N, it executes the step process of step S13.

[0057] In step S13, the control device 130 determines whether the additive manufacturing of the bead N has been completed on the manufacturing surface B1 of the base material B. That is, if the additive manufacturing of the bead N to be formed this time, i.e., the melting process and the heat retention process, has been completed, the control device 130 determines "Yes" and executes the step processing of step S14. On the other hand, if the melting process and the heat retention process of the bead N to be formed this time have not been completed, the control device 130 determines "No" and repeatedly executes the step processing of step S12 until the additive manufacturing of the bead N has been completed.

[0058] In step S14, the control device 130 determines whether or not the formation of the additive product FF, i.e., the plurality of beads N, to be formed on the building surface B1 of the base material B has been completed. That is, if the additive manufacturing of the additive product FF (the plurality of beads N) to be formed on the building surface B1 of the base material B has been completed, the control device 130 determines "Yes" and executes the step processing of step S15, thereby terminating the execution of the additive manufacturing device control program, i.e., the additive manufacturing processing.

[0059] On the other hand, if the additive manufacturing of the additive product FF to be formed on the building surface B1 of the base material B has not been completed, the control device 130 determines "No" and returns to step S11, and executes the step processing up to step S13. Then, the control device 130 repeatedly executes each step processing from step S11 to step S13 until it determines "Yes" in step S14.

[0060] Specifically, immediately after the additive manufacturing device control program starts to be executed, a bead N1 is additively manufactured as an additive product FF on the building surface B1 of the substrate B, as shown in FIG. 11. After the bead N1 is formed, a heat accumulation region SR is formed near the formation position AB of the bead N1, i.e., on both sides of the substrate B in the circumferential direction, due to the irradiation of the melting light beam MBM and the heat retention light beam KBM, and the temperature is high. Therefore, when the control device 130 next forms the bead N2, as shown in FIG. 12, when executing step S11 of the additive manufacturing device control program, the control device 130 determines the formation position BB of the bead N2 to be a position rotated a quarter of a turn (a position rotated 90 degrees) in the circumferential direction of the substrate B from the heat accumulation region SR including the formation position AB of the bead N1 so as to be separated from the heat accumulation region SR generated by the formation of the bead N1. Then, the control device 130 additively manufactures the bead N2 at the formation position BB.

[0061] Next, because the heat accumulation area SR has been formed near the formation position BB of the bead N2 and is in a high temperature state, when forming the next bead N3, the control device 130, during execution of step S11 of the additive manufacturing apparatus control program, determines a position CB for the bead N3 that is a quarter-turn (90-degree rotation) from the formation position BB of the bead N2 in the circumferential direction of the substrate B so as to be away from the heat accumulation area SR created by the formation of the bead N2, as shown in FIG. 13 . In other words, a position that is a half-turn (180-degree rotation) from the heat accumulation area SR including the formation position AB of the bead N1. Then, the control device 130 additively manufactures the bead N3 at the formation position CB. Then, the control device 130 similarly determines a position that is a quarter-turn (90-degree rotation) from the heat accumulation area SR including the formation position of the previous bead N as the formation position of the current bead N, and repeats this process of forming the bead N, until the additive manufacturing of multiple beads N on the manufacturing surface B1 is completed.

[0062] As a result, the formation position where the bead N is formed this time is away from the heat accumulation range SR, so no cooling is required and the effects of heat accumulation associated with the formation of the previous bead N can be eliminated. Therefore, excess energy can be suppressed when forming the bead N, which prevents the expansion of the molten pool MP and allows the bead N to be formed appropriately. As a result, an additive product FF consisting of multiple beads N can be accurately additively formed on the building surface B1 of the base material B.

[0063] As can be understood from the above explanation, with the additive manufacturing apparatus 100, the control device 130 can determine the formation position BB of the current bead N2 as a position that is one-quarter of the way around (90 degrees) away from the heat accumulation area SR that occurred on the build surface B1 of the substrate B when the previous bead N1 was formed. This prevents excessive energy from being supplied to the build surface B1 of the substrate B by the melting light beam MBM and the heat-retaining light beam KBM when the current bead N2 is formed. As a result, excessive expansion of the molten pool MP that forms the current bead N2 (bead N3) can be prevented. Therefore, the additive manufacturing apparatus 100 can additively manufacture a high-quality additive product FF, i.e., a homogeneous coating with a consistent amount of penetration (dilution) across the entire build surface B1.

[0064] (5. First alternative example) In the above-described example, a plurality of beads N are sequentially formed linearly in the axial direction on the building surface B1, which is the circumferential surface of the columnar or cylindrical base material B, to form an additive product FF (additive manufacturing). However, when forming a plurality of beads N on the building surface B1, which is the circumferential surface of the columnar or cylindrical base material B, each bead N is not limited to being formed linearly, and each bead N can be sequentially formed along the circumferential direction of the building surface B1. Specifically, as shown in FIG. 14, for example, each bead N can be formed spirally on the building surface B1.

[0065] 14, for example, when a bead N1 is formed spirally on the printing surface B1, a bead N2 is formed spirally on the printing surface B1 at a position spaced apart from the heat storage area SR that is created by the formation of the bead N1 in the axial direction of the base material B. By forming the bead N2 at a position spaced apart from the bead N1 in the axial direction, the heat storage area SR (see FIG. 7) near the bead N1 is cooled to an appropriate temperature, so that a bead N3 is formed adjacent to the bead N1, for example. Therefore, the first modified example also achieves the same effects as the present example described above.

[0066] (6. Second alternative example) In the above-described present example and first modified example, the case where the base material B is columnar or cylindrical has been described as an example. However, the shape of the base material B for additively manufacturing the additive product FF is not limited to columnar or cylindrical, and may be a plate-like shape having a flat printing surface B1. Specifically, as shown in Fig. 15, the base material B is a flat plate, and multiple beads N can be formed on the flat printing surface B1.

[0067] In this case, as shown in Fig. 15, for example, if bead N1 is formed linearly on the flat printing surface B1, bead N2 is formed linearly at a position (position separated to the right in Fig. 15) away from the heat storage area SR that occurs on printing surface B1 due to the formation of bead N1. By forming bead N2 at a position separated from bead N1, the heat storage area SR (see Fig. 7) near bead N1 is cooled to an appropriate temperature, so that bead N3 is formed adjacent to bead N1, for example. Therefore, the second modified example also achieves the same effects as the present example described above.

[0068] (7. Other Examples) In the above-described example, the control device 130 determines, in step S11 of the additive manufacturing device control program, the formation position of the current bead N to be a position rotated a quarter of the way around in the circumferential direction of the substrate B (a position rotated 90 degrees) from the heat accumulation range SR that occurred with the formation of the previous bead N. Alternatively, in step S11, the control device 130 can also determine, as the formation position of the current bead N, a position rotated a half of the way around in the circumferential direction of the substrate B (a position rotated 180 degrees) from the heat accumulation range SR that occurred with the formation of the previous bead N.

[0069] Furthermore, in the above-described examples and the like, the additive manufacturing apparatus 100 has been described as employing the LMD method. Instead, even if the additive manufacturing apparatus employs the SLM method, it is possible to suppress excessive expansion of the molten pool. When SLM is employed, for example, it is possible to melt and solidify the powder material P in other areas separated from the area where the powder material P is spread by scanning the melting light beam MBM and the heat-retaining light beam KBM. As a result, even when SLM is employed, it is possible to expect the same effects as the above-described examples and the like. [Explanation of symbols]

[0070] 100...additive manufacturing apparatus, 110...powder material supply device, 111...hopper, 111a...piping, 112...valve, 112a...powder introduction valve, 112b...powder supply valve, 112c...gas introduction valve, 113...gas cylinder, 113a...piping, 114...spray nozzle, 114a...piping, 115...container, 120...light beam irradiation device, 121...melting light beam irradiation device, 121a...melting light beam generation unit, 121b...melting light beam irradiation unit, 122...heat-retaining light beam irradiation device, 122a...heat-retaining light beam generation unit, 1 22b...heat-retaining light beam irradiation unit, 122c...container, 123...moving device, 123a...first robot arm, 123b...second robot arm, 130...control device, 140...imaging device, B...substrate, B1...build surface, C...central axis, FF...additively manufactured product, N...bead, MP...molten pool, KBM...heat-retaining light beam, MBM...melting light beam, MS...melting light irradiation range, KS...heat-retaining light irradiation range, M1...motor, M2...motor, P...powder material, P1...hard powder material, P2...bonded powder material, SD...scanning direction, SR...heat accumulation range

Claims

1. a powder material supplying device that supplies a powder material including a hard material and an ultra-hard binder to a substrate; a melting light beam irradiation device that irradiates a predetermined melting light irradiation range with a melting light beam that heats and melts the molding surface of the base material and the powder material supplied to the molding surface of the base material to a melting point or higher; a heat-retaining light beam irradiating device that irradiates a predetermined heat-retaining light irradiation range that surrounds a position overlapping the melting light irradiation range and at least a position on the rear side of the melting light irradiation range in the scanning direction with a heat-retaining light beam that heats the material to a temperature below the melting point and keeps it warm; a control device that independently controls each of the melting light beam irradiation device and the heat-keeping light beam irradiation device with respect to the irradiation of the melting light beam and the heat-keeping light beam, and the relative scanning of the melting light beam and the heat-keeping light beam with respect to the modeling surface of the base material; an additive manufacturing apparatus for additively manufacturing an additive product by forming a plurality of beads on the build surface of the substrate, The control device a heat accumulation range is defined as a range of the modeling surface of the base material that has been heated by the heat-retaining light beam irradiated in association with the previous formation of the bead, and a position spaced from the heat accumulation range is determined as a formation position for forming the current bead; Or, An additive manufacturing device that defines the heat-retaining light irradiation range of the heat-retaining light beam irradiated in conjunction with the formation of the previous bead as a heat storage range, and determines the formation position of the current bead so that the heat-retaining light irradiation range of the heat-retaining light beam irradiated in conjunction with the formation of the current bead does not overlap with the heat storage range.

2. The substrate is columnar or cylindrical, the molding surface of the base material is a peripheral surface of the base material, The additive manufacturing device according to claim 1 , wherein the control device determines the formation position to be a position spaced apart from the heat accumulation area in a circumferential direction of the peripheral surface of the substrate.

3. The additive manufacturing device according to claim 2 , wherein the control device determines the formation position to be a position separated from the heat accumulation area by a quarter of a circumference of the peripheral surface of the substrate.

4. The control device controls the relative attitude of the heat-retaining light beam irradiation device with respect to the melting light beam irradiation device so that the heat-retaining light irradiation range, which is an irradiation range irradiated by the heat-retaining light beam and is larger than the melting light irradiation range, is superimposed on the melting light irradiation range. An additive manufacturing device as described in any one of claims 1 to 3.

5. The additive manufacturing device according to claim 4 , wherein the control device controls the attitude of the heat-keeping light beam irradiating device in a state where the irradiation direction of the heat-keeping light beam is tilted with respect to the irradiation direction of the melting light beam.

6. The additive manufacturing device according to claim 4 or 5, wherein the irradiation direction of the melting light beam is a direction perpendicular to the build surface of the substrate.

7. An additive manufacturing device according to any one of claims 4 to 6, wherein the heat-retaining light irradiation range is longer on the rear side than on the front side in the scanning direction of the melting light beam relative to the melting light irradiation range.

8. The additive manufacturing apparatus according to any one of claims 1 to 7, wherein the powder material supply device supplies the powder material to the substrate by spraying it, and is configured to be movable integrally with the melting light beam irradiation device.

9. An additive manufacturing device according to any one of claims 1 to 8, wherein the control device controls the scanning of the heat-preserving light beam irradiated by the heat-preserving light beam irradiation device so as to follow the trajectory of the scanning of the melting light beam irradiated by the melting light beam irradiation device.

10. The additive manufacturing apparatus according to any one of claims 1 to 9, wherein the heat-retaining light beam irradiation device heats the building surface of the substrate to keep it warm.

11. An additive manufacturing apparatus according to any one of claims 1 to 10, wherein the melting point of the hard material is higher than the melting point of the ultra-hard binder.

12. The additive manufacturing apparatus of claim 11 , wherein the hard material is tungsten carbide (WC).

13. An additive manufacturing apparatus according to any one of claims 1 to 12, wherein the superhard binder is cobalt (Co) or nickel (Ni).

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