Additive manufacturing apparatus and additive manufacturing method

Abstract

To provide an additive manufacturing device which can prevent defective lamination while suppressing deterioration of molding efficiency.SOLUTION: An additive manufacturing device 1 includes a wire nozzle 12 which delivers wire 21 as additive material onto a working surface, a beam nozzle 13 which irradiates the working surface with laser beams for melting the wire 21 and a cooling material nozzle 72 which delivers cooling material 78 having a melting point lower than that of the wire 21 and a thermal conductivity higher than that of the wire 21. Therein, deposits of molten wire 21 are solidified, thereby, the deposits for one layer are laminated, a cooling layer is arranged such that the cooling layer formed from cooling material 78 is brought into contact with the deposits during solidification and a plurality of layers of the deposits are laminated and, thereby, a molded object 41 is formed.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an additive manufacturing apparatus and an additive manufacturing method for laminating a shaped object.

Background Art

[0002] As a technique for manufacturing a three-dimensional object from a metallic material, a technique called additive manufacturing (AM) has been conventionally known. The additive manufacturing method is classified into several types according to materials, lamination methods, etc. The DED (Directed Energy Deposition) method is a method of forming a three-dimensional object from a deposit obtained by selectively melting and solidifying a material by feeding a material to be laminated from a nozzle attached to a processing head and applying energy as a heat source such as a laser, an electron beam, or an arc discharge, and further repeating such a process.

[0003] The DED method has advantages such as a high forming speed, easy switching of the laminated material, and few restrictions on the forming size compared to other additive manufacturing methods. In this DED method, when a new layer is laminated on the formed layer, lamination defects such as sagging, melting, and dropping may occur depending on the temperature, shape, etc. of the previous layer. Therefore, it is desired to prevent lamination defects such as sagging.

[0004] The lamination forming apparatus method described in Patent Document 1 improves the solidification speed of molten metal by interrupting the supply of the filler metal and supplying a cooling gas from the shield gas nozzle of the torch when the temperature of the welding bead is higher than the temperature at which the next layer can be laminated, thereby preventing lamination defects such as sagging.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

[0006] However, the technology described in Patent Document 1 had the problem that the molding process stopped every time the cooling step of supplying cooling gas was entered, resulting in a decrease in molding efficiency.

[0007] This disclosure has been made in view of the above, and aims to provide an additive manufacturing apparatus that can prevent layer defects while suppressing a decrease in molding efficiency. [Means for solving the problem]

[0008] To solve the above-mentioned problems and achieve the objective, the additive manufacturing apparatus of this disclosure comprises a material nozzle for delivering additive material to the processing surface, a beam nozzle for irradiating the processing surface with a beam that melts the additive material, and a cooling material nozzle for delivering a cooling material that has a lower melting point and higher thermal conductivity than the additive material. A layer of deposit is stacked as the molten additive material solidifies, and a cooling layer formed from the cooling material is positioned so as to come into contact with the solidifying deposit, thereby forming a molded object by stacking multiple layers of deposits. [Effects of the Invention]

[0009] The additive manufacturing apparatus described herein has the effect of preventing layer defects while suppressing a decrease in molding efficiency. [Brief explanation of the drawing]

[0010] [Figure 1] Overall diagram showing the schematic configuration of the additive manufacturing apparatus according to Embodiment 1 [Figure 2] Figure 1 shows a configuration diagram illustrating the processing area of ​​the additive manufacturing apparatus. [Figure 3] Figure 1 is a diagram illustrating the function of the control device shown. [Figure 4] Figure 1 shows an example of an object manufactured by the additive manufacturing apparatus. [Figure 5] Figure 1 is a diagram illustrating the function of the cooling material supply device. [Figure 6] Cross-sectional view of the deposits and cooling layer formed by the additive manufacturing apparatus shown in Figure 1. [Figure 7] Flowchart showing the processing procedure of the additive manufacturing apparatus according to Embodiment 1. [Figure 8] A diagram illustrating the function of the cooling material supply device according to Embodiment 2. [Figure 9] A diagram illustrating the process of forming a cooling layer and deposits in the additive manufacturing apparatus according to Embodiment 4. [Modes for carrying out the invention]

[0011] The additive manufacturing apparatus and additive manufacturing method according to embodiments of this disclosure will be described in detail below with reference to the drawings. Note that components using the same reference numerals in each figure represent substantially the same components.

[0012] Embodiment 1. First, the general configuration of the additive manufacturing apparatus 1 according to Embodiment 1 will be described. Figure 1 is an overall diagram showing the general configuration of the additive manufacturing apparatus 1 according to Embodiment 1.

[0013] The additive manufacturing apparatus 1 performs DED (Direct Deposition Modeling) additive manufacturing using wire-shaped additive material. The additive manufacturing apparatus 1, which additively manufactures three-dimensional objects, has a chiller 2 for cooling the apparatus 1 and a laser oscillator 3 that emits a laser beam 31 (not shown in Figure 1), which is a heat source for melting the additive material. The additive manufacturing apparatus 1 also has a wire supply device 4 for supplying wire 21, which is the additive material, and a gas supply device 5 for supplying shielding gas 32 (not shown in Figure 1) for suppressing oxidation and cooling the deposit 44, which will be described later. The additive manufacturing apparatus 1 also has a cooling material supply device 71 for supplying cooling material 78 to the deposit 44 for cooling the deposit 44.

[0014] The additive manufacturing apparatus 1 further includes a processing head 11 that supplies a wire 21, which is an additive material, a laser beam 31 serving as a heat source for melting the wire 21, and a shielding gas 32 to a processing region 43.

[0015] The processing head 11 is connected to a chiller 2, a laser oscillator 3, a wire supply device 4, and a gas supply device 5. The processing head 11 and the laser oscillator 3 are connected by, for example, a fiber cable 17. The processing head 11 includes a wire nozzle 12 for sending out the wire 21 supplied from the wire supply device 4 to the processing region 43, a beam nozzle 13 for irradiating the processing region 43 with the laser beam 31 oscillated by the laser oscillator 3, and a gas nozzle 14 for ejecting the shielding gas 32 toward the processing region 43. The additive manufacturing apparatus 1 further includes a coolant nozzle 72 for sending out a coolant 78 supplied from a coolant supply device 71 to the processing region 43. The wire nozzle 12 is an example of a material nozzle that supplies an additive material. The processing region 43 is a region where the traveling direction of the laser beam 31 and the wire 21, which is an additive material, intersect.

[0016] The additive manufacturing apparatus 1 further includes a base plate 16 that serves as a base for laminating the shaped object 41, a moving stage 15 on which the base plate 16 is installed, and a moving stage fixing portion 18 for fixing the moving stage 15.

[0017] The additive manufacturing apparatus 1 further includes a control device 6. The control device 6 controls the operation of the additive manufacturing apparatus 1 by controlling each part of the additive manufacturing apparatus 1. Here, it is assumed that the XY plane including the X-axis and the Y-axis is parallel to the horizontal plane, and the direction of the Z-axis is the vertical direction perpendicular to the X-axis and the Y-axis.

[0018] FIG. 2 is a configuration diagram showing a portion of the processing area 43 of the additive manufacturing apparatus 1 shown in FIG. 1. The additive manufacturing apparatus 1 irradiates a wire 21, which is an additive material supplied from a wire supply apparatus 4 toward a processing surface 42, with a laser beam 31 emitted from a laser oscillator 3, and laminates beads, which are linear deposits 44 formed by melting and solidifying the wire 21, to manufacture a shaped object 41. Here, the shaped object 41 refers to an object (three-dimensional object) formed by laminating the deposits 44.

[0019] In the additive manufacturing apparatus 1, both the moving stage 15 and the processing head 11 are movable, and at least one of the moving stage 15 and the processing head 11 moves according to the control of the control apparatus 6, so that the relative positions of the moving stage 15 and the processing head 11 change, and the processing area 43 on the processing surface 42 moves.

[0020] The moving stage 15 can rotate around an A-axis, which is parallel to the X-axis and passes through the center of the Y-axis of the moving stage 15, and a θ-axis, which is parallel to the Z-axis and passes through the center of the Y-axis of the moving stage 15. The processing head 11 can move in the X-axis direction, Y-axis direction, and Z-axis direction. Here, the moving directions of the moving stage 15 and the processing head 11 are examples. For example, the control apparatus 6 may control the moving stage 15 to move in the X-axis direction, Y-axis direction, and Z-axis direction, and control the processing head 11 to rotate around the A-axis and θ-axis. Thereby, the irradiation position of the laser beam 31 on the processing surface 42 changes.

[0021] A base plate 16, which serves as a base for laminating the shaped object 41, is installed on the moving stage 15. The base plate 16 is a metal plate having a plane parallel to the XY plane. Note that the base plate 16 may be cylindrical or blade-shaped in addition to being a metal plate having a plane. The processing surface 42 is a surface to which an additive material is added. At the start of shaping, one surface of the base plate 16 becomes the processing surface 42, and when the shaped object 41 is formed on the base plate 16 and the shaping progresses, the surface of the laminated shaped object 41 becomes the processing surface 42.

[0022] The gas nozzle 14 ejects shielding gas 32 toward the processing area 43 to suppress oxidation and cool the deposit 44. The gas supply device 5 supplies the shielding gas 32 to the gas nozzle 14 according to the control of the control device 6.

[0023] The wire 21 supplied from the wire supply device 4 is fed towards the processing surface 42 by the wire nozzle 12. Here, the wire 21 is a wire-shaped additive material and is made of metal.

[0024] The laser beam 31 emitted by the laser oscillator 3 propagates to the beam nozzle 13 via the fiber optic cable 17, which is an optical transmission path, and is irradiated onto the processing surface 42 from the beam nozzle 13. The position where the wire 21 is fed out on the processing surface 42 and the irradiation position of the laser beam 31 overlap, causing the wire 21 to melt on the processing surface 42 due to the thermal energy of the laser beam 31, and forming a deposit 44. The irradiation path of the laser beam 31 is determined based on the processing program. The control device 6 creates data indicating the irradiation path of the laser beam 31 in advance from the processing program and uses it to control additive manufacturing.

[0025] The laser beam 31 is just one example of a heat source for melting the additive material. The heat source for melting the additive material is not limited to the laser beam 31, but may also be an electron beam, an arc discharge, or the like. Furthermore, the irradiation with the laser beam 31, the supply of the wire 21, and the ejection of the shielding gas 32 do not have to be performed in the order described, the order may be changed, or they may be controlled to be performed simultaneously.

[0026] The additive manufacturing apparatus 1 repeatedly performs the process of forming deposits 44, thereby forming a three-dimensional molded object 41. The newly formed deposits 44 are integrated with the already formed lower layers of deposits 44 during the formation of the new deposits 44. The additive manufacturing apparatus 1 of Embodiment 1 has a function to promote heat dissipation from the deposits 44 to prevent the occurrence of layering defects without stopping the molding process.

[0027] Figure 3 is a diagram illustrating the function of the control device 6 shown in Figure 1. The control device 6 is connected to each part of the additive manufacturing apparatus 1, specifically the laser oscillator 3, wire feeder 4, gas supplyer 5, processing head 11, moving stage 15, and cooling material supplyer 71. The control device 6 controls the additive manufacturing apparatus 1 according to the processing program 61 transmitted from the CAM (Computer-Aided Manufacturing) 63. The CAM 63 creates the processing program 61 from shape data created in the CAD (Computer-Aided Design) 62.

[0028] The control device 6 controls the timing, direction, and amount of movement of the processing head 11. The control device 6 controls the timing of the laser oscillator 3 emitting the laser beam 31, the intensity of the laser beam 31, etc. The control device 6 controls the timing of the wire supply device 4 supplying the wire 21 to the processing head 11, the wire 21 delivery speed, etc. The control device 6 controls the timing of the cooling material supply device 71 supplying the cooling material 78, the cooling material 78 delivery speed, etc. The control device 6 controls the timing of the gas supply device 5 supplying shielding gas 32 to the processing head 11, the supply amount, etc. The control device 6 controls the timing, direction, and amount of movement of the moving stage 15. The chiller 2 cools the additive manufacturing apparatus 1 by supplying cooling water 45 to parts that may generate heat, such as the laser oscillator 3 and the processing head 11.

[0029] In this description, an example of a DED additive manufacturing apparatus 1 has been explained, but the apparatus used in the DED molding method is not limited to the example shown. Furthermore, the deposition of deposits 44 by the additive manufacturing apparatus 1 according to Embodiment 1 can be carried out in accordance with known molding methods, and it goes without saying that various apparatuses can be used in such molding methods.

[0030] As described above, the additive manufacturing apparatus 1 has a function to promote heat dissipation of the deposits 44 in order to prevent the occurrence of layering defects. Here, layering defects caused by the additive manufacturing apparatus 1 will be explained. The molded object 41 manufactured by the additive manufacturing apparatus 1 is formed by stacking an upper layer of deposits 44 on top of a lower layer of deposits 44 in the Z-axis direction during the process in which the wire 21 melts and deposits 44 are formed.

[0031] Figure 4 shows an example of a molded object 41 manufactured by the additive manufacturing apparatus 1 shown in Figure 1. As shown in Figure 4, when a molded object 41 is manufactured that has walls that form an inclined angle with respect to the base plate 16, such as a molded object 41 with a mortar-shaped wall, the upper layer of deposits 44 is stacked in a circular orbit while increasing in diameter relative to the lower layer of deposits 44. In other words, there is a part below the upper layer of deposits 44 where the lower layer of deposits 44 does not exist. At this time, the wire 21 heated by the laser beam 31 melts and becomes deposits 44, and these deposits 44 solidify.

[0032] Here, during the process from when the wire 21 melts until it reaches the temperature at which it solidifies as sediment 44, gravity can have an effect, potentially causing a lamination defect where the molten added material cannot solidify in the desired position. Examples of lamination defects caused by gravity include sagging, where a portion of the sediment 44 hangs down to the outside of the ring, and melting, where the specified inclination angle cannot be maintained. Sagging occurs, for example, when the sediment 44 is laid while the preceding layer has not fully cooled, and solidification is slower than cooling. Another example of a lamination defect caused by gravity is dropping, where the height of the sediment 44 falls below the specified level due to the inability to maintain the inclination angle, and the distance between the lower layer of sediment 44 and the wire 21 increases, causing the wire 21 to drop before it reaches the sediment 44.

[0033] As the number of layers increases, the heat accumulated due to the layering increases, and the probability of the above-mentioned layering defects occurring increases. Therefore, the additive manufacturing apparatus 1 of Embodiment 1 prevents layering defects by improving the cooling rate until the wire 21 melts and solidifies as a deposit 44. Alternatively, the additive manufacturing apparatus 1 may prevent layering defects by improving the cooling rate after the wire 21 has melted and solidified as a deposit 44.

[0034] Furthermore, since lamination defects such as drops are likely to occur at the start of lamination, it is desirable to perform lamination continuously without stopping the process as much as possible. In other words, processes that involve cooling after lamination and then restarting lamination are undesirable because they are likely to cause lamination defects such as drops.

[0035] Therefore, in Embodiment 1, once the additive manufacturing apparatus 1 starts stacking the sediment 44, it cools the sediment 44 with the cooling material 78 while continuously stacking without stopping the stacking process. That is, the additive manufacturing apparatus 1 performs the stacking of sediment 44 and the supply of the cooling material 78 to the sediment 44 simultaneously. The additive manufacturing apparatus 1 supplies the cooling material 78 so that the sediment 44 and the cooling material 78 are in contact. In Embodiment 1, the additive manufacturing apparatus 1 stacks the cooling material 78 after stacking the sediment 44. Specifically, the additive manufacturing apparatus 1 stacks one layer of cooling material 78 after stacking one layer of sediment 44. The additive manufacturing apparatus 1 stacks the next layer of sediment 44 while stacking one layer of cooling material 78.

[0036] The cooling material supply device 71 of Embodiment 1 supplies cooling material 78 along a stacking path through which the wire 21 is fed and the deposits 44 are stacked. Figure 5 is a diagram illustrating the function of the cooling material supply device 71 shown in Figure 1. In addition to the wire 21, Figure 5 also shows the cooling material 78 and other components.

[0037] The additive manufacturing apparatus 1 forms cooling layers 79 and 79X using a cooling material 78. Cooling layer 79 shown in Figure 5 is used to cool the deposit 44, and cooling layer 79X shown in Figure 5 is used to cool the deposit 44 one layer prior to the deposit 44 (shown as the molded object 41 in Figure 5).

[0038] The additive manufacturing apparatus 1 includes a cooling material cable 76 that changes the direction of travel of the cooling material 78 fed from a cooling material reel (not shown). The additive manufacturing apparatus 1 may change the direction of travel of the cooling material 78 by using multiple pulleys instead of the cooling material cable 76. The additive manufacturing apparatus 1 includes a cooling material feed roller 73 that changes the direction of travel of the cooling material 78 fed through the cooling material cable 76 and feeds the cooling material 78 toward the deposit 44 in the processing area 43. The cooling material feed roller 73 also plays a role in correcting the distortion of the cooling material 78 that has been imparted by the cooling material reel and the cooling material cable 76. After passing through the cooling material nozzle 72, the cooling material 78 is supplied to the deposit 44 (solidifying deposit 44) made of wire 21 melted by the laser beam 31.

[0039] The control device 6 sets the supply path for the cooling material 78 according to the processing program 61. The cooling material supply device 71 includes a cooling material reel around which the cooling material 78 is wound, and a cooling material holder (not shown) on which the cooling material reel is installed. A rotary motor (not shown) is also installed on the central axis of the cooling material holder. When the rotary motor is driven, the cooling material holder and the cooling material reel rotate, and the cooling material 78 is fed out from the cooling material reel. The control device 6 sets the value (rotation amount) of the rotary motor and the amount of cooling material 78 to be fed, which is linked to the value of the rotary motor, according to the processing program 61.

[0040] Similarly, the control device 6 sets the direction of supply of the cooling material 78 by the cooling material supply device 71 according to the processing program 61 so that the laser beam 31 does not directly irradiate the cooling material nozzle 72, the cooling material 78, and the cooling material pressing roller 74. Since it becomes difficult for the cooling material pressing roller 74 to press the cooling material 78 if internal pressure remains in the cooling material 78, the supply direction is determined so that the direction of travel (delivery direction) of the cooling material 78 is tangent to the deposit 44. That is, the cooling material nozzle 72 delivers the cooling material 78 so that the delivery direction of the cooling material 78 is tangent to the deposit 44. The tangent direction to the deposit 44 is the stacking direction of the deposit 44. That is, the tangent direction to the deposit 44 is the direction parallel to the contact surface between the cooling layer 79 and the deposit 44. For example, if the deposit 44 is formed in an inverted conical mortar shape, the tangent direction to the deposit 44 is the generatrix direction. In this way, the cooling material 78 is delivered tangentially to the deposit 44, so that the cooling material 78 is supplied onto the lower cooling layer 79 without distortion.

[0041] The supplied cooling material 78 is subjected to pressure by the cooling material compression roller 74 so that it conforms to the shape of the deposit 44. In other words, the cooling material compression roller 74 presses the cooling material 78 against the deposit 44 along the deposit 44. As a result, the cooling material 78 is laid in close contact with the side surface of the deposit 44.

[0042] The amount of pressure applied to the cooling material 78 varies depending on the mechanical properties of the cooling material 78, such as its material, outer diameter, and Young's modulus. The amount of pressure applied to the cooling material 78 is controlled by the rigidity of the crimping roller fixture 75. This control may be achieved by changing the material of the crimping roller fixture 75, changing the structure of the crimping roller fixture 75, applying electrical control to the crimping roller fixture 75, or by a combination of these methods. In addition, the cooling material 78 undergoes a temperature change due to the heat retained by the deposit 44. Therefore, the creator of the processing program 61 or the designer of the additive manufacturing apparatus 1 determines the amount of pressure applied to the cooling material 78 based on the change in Young's modulus with respect to the temperature change of the cooling material 78. The additive manufacturing apparatus 1 controls the amount of pressure applied to the cooling material 78 to be this determined amount. This allows the additive manufacturing apparatus 1 to supply and crimp the cooling material 78 without causing it to break.

[0043] Thus, the pressure applied to the cooling material 78 by the cooling material compression roller 74 by the additive manufacturing apparatus 1 is a value that takes into account the change in the mechanical properties of the cooling material 78 due to the temperature change applied to the cooling material 78, depending on the type of molded object 41. In other words, the pressure applied to the cooling material 78 by the cooling material compression roller 74 is a value that does not cause the cooling material 78 to break. As a result, the cooling material 78 is laminated as a cooling layer 79 without breaking and comes into contact with the deposit 44.

[0044] Here, the material used for the cooling material 78 is characterized by having a lower melting point and higher thermal conductivity than the material used for the wire 21. An example of a combination of wire 21 and cooling material 78 is a combination of SUS (Steel Use Stainless) and copper. That is, SUS is used for the wire 21 and copper is used for the cooling material 78.

[0045] Furthermore, the outer diameter (height dimension) of the cooling material 78 is the same as the Z-direction pitch height (Z-direction pitch height α, described later) of the deposit 44 when it is formed. The outer diameter of the deposit 44 corresponds to the supply interval of the additive material determined by the processing program 61 for controlling the additive manufacturing apparatus 1. When one layer of deposit 44 is stacked, the cooling material nozzle 72 forms a cooling layer 79 to the same height as one layer of deposit 44. In other words, the additive manufacturing apparatus 1 forms the cooling layer 79 so that the height of one layer of deposit 44 is the same as the height of one layer of cooling layer 79. As a result, the cooling layer 79 is stacked without gaps.

[0046] As mentioned earlier, the wire 21 is heated and melted by the laser beam 31 and solidifies as a deposit 44. The more layers there are, the greater the heat stored by the layering, and the slower the cooling rate of the deposit 44 becomes.

[0047] The above process using the cooling material 78 deposits a cooling layer 79 in the outer periphery direction of the deposit 44. Figure 6 is a cross-sectional view of the deposit 44 and cooling layer 79 formed by the additive manufacturing apparatus 1 shown in Figure 1. Figure 6 shows a cross-sectional view of the deposit 44 and cooling layer 79 when cut by a plane parallel to the XZ plane.

[0048] As mentioned above, the height of one layer of the cooling material 78 is the same as the Z-direction pitch height α of the deposit 44, which is determined according to the processing program 61. Although not shown in Figure 6, the leading edge (lower end) of the cooling layer 79 is fixed to the base plate 16. The method of fixing the cooling material 78 to the base plate 16 is not limited to fastening, screws, or joining. The first layer of the deposit 44 is the initial layer, and because the heat path of the base plate 16 is large, lamination defects due to heat accumulation do not occur. For this reason, the formation of the cooling layer 79 may be omitted for the first layer of the deposit 44. In this case, a fastener or the like is placed on the side of the first layer of the deposit 44, and the lower end (first layer) of the cooling layer 79 is fixed to this fastener. For the second layer and subsequent layers of the deposit 44, the supply height of the cooling material 78 is the same as the lamination height of the deposit 44.

[0049] Furthermore, the cooling layer 79 is detached from the deposit 44 after the completion of the layering process. Detachment is performed, for example, by machining. Alternatively, if the maximum surface temperature of the deposit 44 does not exceed the melting temperature of the cooling layer 79 (cooling material 78), detachment may be performed after the completion of the molding process using the difference in thermal expansion coefficients. In this case, the maximum surface temperature of the deposit 44 may be measured or calculated by numerical calculation or the like.

[0050] Figure 7 is a flowchart showing the processing procedure performed by the additive manufacturing apparatus 1 according to Embodiment 1. The wire nozzle 12 of the additive manufacturing apparatus 1 feeds the wire 21, which is the additive material, toward the processing surface 42 (step S10).

[0051] The laser oscillator 3 emits a laser beam 31. The beam nozzle 13 irradiates the wire 21, which will become the processing surface 42, with the laser beam 31 to build up a deposit 44 (step S20). In other words, when the laser beam 31 irradiates the wire 21, the wire 21 melts and becomes a deposit 44. Once the irradiation of the laser beam 31 is complete, the solidification of the deposit 44 begins.

[0052] The cooling material supply device 71 of the additive manufacturing apparatus 1 delivers cooling material 78 when irradiation with the laser beam 31 is completed, that is, when solidification of the deposit 44 begins (step S30). The additive manufacturing apparatus 1 brings the cooling layer 79 formed from the cooling material 78 into contact with the solidifying deposit 44 (step S40). The additive manufacturing apparatus 1 brings one layer of cooling layer 79 into contact with one layer of deposit 44. In this way, the additive manufacturing apparatus 1 brings the cooling layer 79 into contact with each layer of the formed deposit 44. The deposit 44 solidifies while being cooled by the cooling layer 79. The additive manufacturing apparatus 1 may omit the formation and contact of the cooling layer 79 with the first layer of deposit 44. The additive manufacturing apparatus 1 may also cool the solidified deposit 44 with the cooling layer 79. Even if the cooling layer 79 comes into contact with the deposit 44 after it has solidified, if the cooling rate of the deposit 44 increases, the additive manufacturing apparatus 1 can suppress the sagging of the next layer. Thus, the additive manufacturing apparatus 1 may cool the heat-dissipating deposit 44 in the cooling layer 79.

[0053] As described above, the additive manufacturing apparatus 1 of Embodiment 1 supplies a cooling material 78, which has a lower melting point and higher thermal conductivity than the wire 21 used for additive manufacturing, along the deposit 44 formed using the wire 21. This allows the additive manufacturing apparatus 1 to improve the cooling rate until the wire 21 melts and solidifies as the deposit 44, thereby preventing the deposit 44 from dripping down between the time the wire 21 melts and solidifies. Furthermore, since the additive manufacturing apparatus 1 does not require a cooling step to supply cooling gas to improve the cooling rate of the wire 21, it is not necessary to stop the manufacturing process each time a cooling step is entered. Therefore, the additive manufacturing apparatus 1 can prevent defects in the layering while suppressing a decrease in manufacturing efficiency.

[0054] Embodiment 2. Next, Embodiment 2 will be described using Figure 8. In Embodiment 2, the additive manufacturing apparatus 1 prevents molding defects such as voids by cooling the cooling material 78 before stacking it as a cooling layer 79. In other words, the additive manufacturing apparatus 1 of Embodiment 2 prevents stacking defects in the deposit 44 by cooling the cooling material 78 before it is fed along the deposit 44.

[0055] Figure 8 is a diagram illustrating the function of the cooling material supply device 71 according to Embodiment 2. Among the components in Figure 8, components that achieve the same function as the cooling material supply device 71 of Embodiment 1 shown in Figure 5 are denoted by the same reference numerals, and redundant explanations are omitted.

[0056] In Embodiment 1, the additive manufacturing apparatus 1 improved the cooling rate of the deposit 44 and reduced lamination defects by stacking a cooling layer 79 around the deposit 44 using a cooling material 78 that has a lower melting point and higher thermal conductivity than the material used for the wire 21.

[0057] In this additive manufacturing process, the additive manufacturing apparatus 1 repeatedly performs the process of forming deposits 44, accumulating the deposits 44 until a specific thickness is reached, thereby forming a three-dimensional object 41.

[0058] Furthermore, a known method for accelerating the cooling rate of the deposit 44 is for the additive manufacturing apparatus 1 to cool the deposit using shielding gas 32 or a separate cooling gas. However, when the newly formed deposit 44, created by repeating the process of forming the deposit 44, is integrated with the already formed lower layer of deposit 44, it may solidify while containing an air layer such as external air, shielding gas 32, or cooling gas. When the deposit 44 solidifies while containing an air layer, molding defects such as voids may occur. For this reason, it is desirable to cool the deposit 44 in a short time without increasing the flow rate of shielding gas 32.

[0059] Therefore, the additive manufacturing apparatus 1 of Embodiment 2 improves the cooling rate without generating voids by cooling the cooling material 78 and then stacking it as a cooling layer 79. As a result, the additive manufacturing apparatus 1 of Embodiment 2 further improves the cooling rate of the deposit 44 by the cooling layer 79 compared to the additive manufacturing apparatus 1 of Embodiment 1.

[0060] Typically, nitrogen or argon is used as the shielding gas 32. Here, we will describe the case where the additive manufacturing apparatus 1 uses nitrogen as the shielding gas 32. The additive manufacturing apparatus 1 supplies the shielding gas 32 supplied from the gas supply device 5 to the cooling material 78 as liquid nitrogen in a low-temperature state.

[0061] Here, we will explain the path of the shielding gas 32 supplied from the gas supply device 5. The shielding gas 32 supplied from the gas supply device 5 is sent to the gas nozzle 14 via the cooling material nozzle 72. The shielding gas 32 supplied to the cooling material nozzle 72 is sent to the gas nozzle 14 while cooling the cooling material 78.

[0062] In the additive manufacturing apparatus 1, the temperature of the path is set so that the shielding gas 32 vaporizes before reaching the cooling material nozzle 72. Inside the cooling material nozzle 72, the supply direction of the cooling material 78 and the flow direction of the shielding gas 32 are opposite. That is, a nozzle 81 is provided near the outlet of the cooling material 78 in the cooling material nozzle 72 (the lower end of the cooling material nozzle 72) to send shielding gas 32 from the gas supply device 5 to the cooling material nozzle 72. Also, a nozzle 82 is provided near the inlet of the cooling material 78 in the cooling material nozzle 72 (the upper end of the cooling material nozzle 72) to send shielding gas 32 to the gas nozzle 14. In this way, in the cooling material nozzle 72, the cooling material 78 is fed in from one end (upper end) and the shielding gas 32 is fed in from the other end (lower end).

[0063] This configuration allows the additive manufacturing apparatus 1 to efficiently cool the cooling material 78. The cooled cooling material 78 is stacked as a cooling layer 79, and the temperature difference with the deposit 44 becomes large. In Embodiment 2, the cooling rate is improved compared to Embodiment 1 because the temperature gradient between the cooling layer 79 and the deposit 44 becomes larger. Furthermore, when the structure of the additive manufacturing apparatus 1 as in Embodiment 2 is used, there is no need to introduce a separate cooling gas or increase the amount of shielding gas 32 used. As a result, the additive manufacturing apparatus 1 of Embodiment 2 can further improve the cooling rate with a simple structure. The other configurations of the additive manufacturing apparatus 1 are the same as in Embodiment 1, so their description is omitted.

[0064] As described above, the additive manufacturing apparatus 1 of Embodiment 2 cools the cooling material 78 by flowing shielding gas 32 into the cooling material nozzle 72, and stacks the cooled cooling material 78 as a cooling layer 79. Therefore, it is possible to efficiently cool the deposits 44 that come into contact with the cooling layer 79. Accordingly, the additive manufacturing apparatus 1 of Embodiment 2 can further improve the cooling speed compared to the additive manufacturing apparatus 1 of Embodiment 1.

[0065] Furthermore, in the additive manufacturing apparatus 1 of Embodiment 2, the shielding gas 32 fed in from one end of the cooling material nozzle 72 is discharged from the other end of the cooling material nozzle 72 and ejected towards the processing area 43 via the gas nozzle 14, thus enabling the cooling of the cooling material 78 and the processing area 43 with a simple configuration.

[0066] Embodiment 3. Next, Embodiment 3 will be described. In Embodiment 3, in order to further improve the cooling rate compared to Embodiments 1 and 2, the additive manufacturing apparatus 1 uses a hollow-shaped cooling material 78 to create an air passage inside the cooling layer 79.

[0067] In Embodiment 3, the additive manufacturing apparatus 1 forms a cooling layer 79 using a cooling material 78 having an internal air channel, so the cooling rate of the deposit 44 by the cooling layer 79 is further improved compared to Embodiments 1 and 2.

[0068] As mentioned above, the cooling material 78 is a wire 21 having an outer diameter equal to the pitch height α in the Z direction during molding. Furthermore, the cooling material 78 of Embodiment 3 has a hollow layer inside. The wire shape with the hollow layer may be, for example, a cylindrical shape with the inside of a cylinder hollowed out, or a coil shape with multiple wires twisted together. Thus, the cooling material 78 has a hollow shape. The additive manufacturing apparatus 1 passes a heat transfer medium, such as a cooling gas or liquid, through the inside of the cooling layer 79. As a result, the heat transfer medium passes through the inside of the cooling layer 79.

[0069] The additive manufacturing apparatus 1 of Embodiment 3 promotes heat dissipation from the deposit 44 by, for example, supplying compressed air through the hollow layer of the cooling layer 79. The inlet for the compressed air is the lower end of the cooling layer 79 (the first cooling layer 79) fixed on the base plate 16. As a result, the additive manufacturing apparatus 1 of Embodiment 3 can further improve the cooling rate compared to Embodiments 1 and 2 with a simple structure. The other components of the additive manufacturing apparatus 1 are the same as those of Embodiments 1 and 2, so their description will be omitted.

[0070] In addition, the additive manufacturing apparatus 1 may pre-cool the hollow cooling material 78 before lamination, as in Embodiment 2.

[0071] Thus, the additive manufacturing apparatus 1 of Embodiment 3 forms a cooling layer 79 using a hollow cooling material 78 and cools the deposit 44 using the cooling layer 79, making it possible to efficiently cool the deposit 44 that comes into contact with the cooling layer 79. Therefore, the additive manufacturing apparatus 1 of Embodiment 3, like the additive manufacturing apparatus 1 of Embodiment 2, can further improve the cooling speed compared to the additive manufacturing apparatus 1 of Embodiment 1.

[0072] Embodiment 4. Next, Embodiment 4 will be described. Embodiment 1 described a case in which the additive manufacturing apparatus 1 improves the cooling rate by pressing the cooling material 78 onto the deposit 44 with a cooling material pressing roller 74. The additive manufacturing apparatus 1 of Embodiment 4 brings the side surface of the deposit 44 into contact with the side surface of the cooling layer 79 in a different manner than the additive manufacturing apparatus 1 of Embodiment 1.

[0073] If the side surface of the deposit 44 has a continuous concave surface, it is difficult to press the cooling material 78 onto the deposit 44 unless the diameter of the cooling material pressing roller 74 is smaller than the inner diameter of the concave shape.

[0074] Therefore, the additive manufacturing apparatus 1 of Embodiment 4 first deposits a cooling layer 79, and then deposits material 44 along the side surface of the cooling layer 79. The additive manufacturing apparatus 1 of Embodiment 4 is equipped with a cooling material nozzle (cooling material nozzle 19, described later), and deposits the cooling layer 79 using the cooling material nozzle 19. That is, the additive manufacturing apparatus 1 supplies cooling material 78 from the cooling material nozzle 19, melts the cooling material 78 with a laser beam 31, and solidifies it as a cooling layer 79. As a result, the cooling layer 79 is deposited. The additive manufacturing apparatus 1 deposits the cooling layer 79 by performing additive manufacturing using the DED method described in Embodiments 1 to 3. As a result, the additive manufacturing apparatus 1 deposits the cooling layer 79 at the position described in Embodiments 1 to 3.

[0075] The additive manufacturing apparatus 1 deposits the material 44 so that it is in contact with the side surface of the cooling layer 79. The additive manufacturing apparatus 1 deposits the material 44 by performing the DED method additive manufacturing described in Embodiments 1 to 3. In this case, the additive manufacturing apparatus 1 irradiates the wire 21 with the laser beam 31 so that the laser beam 31 is not irradiated onto the solidifying cooling layer 79.

[0076] Figure 9 is a diagram illustrating the process by which the additive manufacturing apparatus 1 according to Embodiment 4 forms a cooling layer 79 and a deposit 44. In Figure 9, the cooling material nozzle 19, wire nozzle 12, cooling layer 79, deposit 44, etc., are schematically shown.

[0077] In the additive manufacturing apparatus 1 of Embodiment 4, a cooling material nozzle 19 supplies one layer of cooling material 78 to the processing area 43 (not shown in Figure 9). This cooling material 78 melts when irradiated with a laser beam 31, and then solidifies to form one layer of cooling layer 79 (st1).

[0078] The additive manufacturing apparatus 1 deposits material 44 on the side wall surface of the cooling layer 79 using wire 21, which is an additive material (st2). That is, the wire nozzle 12 supplies one layer's worth of wire 21 to the side wall surface of the cooling layer 79. This wire 21 melts when irradiated with the laser beam 31, and then solidifies to form one layer's worth of deposit 44. In this way, the additive manufacturing apparatus 1 deposits material 44 by the same process as described in Embodiments 1 to 3.

[0079] As a result, the additive manufacturing apparatus 1 can press the cooling layer 79 and the deposit 44 together more tightly than in the first embodiment, and consequently, the cooling rate can be further improved compared to the first embodiment.

[0080] Next, the additive manufacturing apparatus 1 cuts off the outside of the cooling layer 79. That is, the additive manufacturing apparatus 1 cuts off the contact surface between the cooling layer 79 and the deposit 44, thereby separating the deposit 44 from the cooling layer 79 (st3).

[0081] The additive manufacturing apparatus 1 may also deposit the material 44 while tilting the base plate 16. In this case, the additive manufacturing apparatus 1 tilts the base plate 16 so that the bottom surface of the material 44 contacts the upper surface of the cooling layer 79. That is, the additive manufacturing apparatus 1 tilts the base plate 16 so that the contact surface between the cooling layer 79 and the material 44 is parallel to the XY plane, and then forms the material 44. In this way, the additive manufacturing apparatus 1 of Embodiment 4 deposits the cooling layer 79, which will become the wall surface, first, and sets the stacking path of the material 44 and the tilt angle of the base plate 16 so that the cooling layer 79 is positioned in the direction of gravity (downward) relative to the material 44. As a result, the additive manufacturing apparatus 1 can efficiently cool even material 44 with complex shapes and prevent stacking defects such as the material 44 sagging. The other configurations of the additive manufacturing apparatus 1 are the same as in Embodiments 1 to 3, so their description is omitted.

[0082] In this way, the additive manufacturing apparatus 1 of Embodiment 4 melts and cools a cooling material 78 as the first layer to deposit a cooling layer 79, and deposits a material 44 on top of the cooling layer 79. As a result, the additive manufacturing apparatus 1 can press the cooling layer 79 and the material 44 together more strongly than in Embodiment 1. Furthermore, the additive manufacturing apparatus 1 of Embodiment 4 can improve the cooling rate, similar to the additive manufacturing apparatus 1 of Embodiment 1.

[0083] The configurations shown in the above embodiments are merely examples, and it is possible to combine them with other known technologies, combine different embodiments, and omit or modify parts of the configuration without departing from the gist of the invention.

[0084] The various aspects of this disclosure are summarized below as an appendix.

[0085] (Note 1) A material nozzle that delivers additional material to the processing surface, A beam nozzle that irradiates the processed surface with a beam that melts the aforementioned additional material, A cooling material nozzle that dispenses a cooling material having a lower melting point and higher thermal conductivity than the aforementioned additive material, Equipped with, As the deposit in which the added material has been melted solidifies, one layer of the deposit is stacked. The cooling layer formed from the cooling material is positioned so as to be in contact with the deposit during solidification. A structure is formed by stacking multiple layers of the aforementioned deposits. An additive manufacturing apparatus characterized by the following features. (Note 2) After the deposit is melted, the cooling material nozzle delivers the cooling material around the deposit so that the cooling layer is formed so that the solidifying deposit and the cooling layer come into contact. The additive manufacturing apparatus described in Appendix 1, characterized by the features described herein. (Note 3) When one layer of the deposit is accumulated, the cooling material nozzle forms the cooling layer to the same height as one layer of the deposit. The additive manufacturing apparatus according to Appendix 1 or 2, characterized by the features described above. (Note 4) The system further comprises a pressure roller for pressing the cooling material onto the deposit as a cooling layer, The pressing roller presses the cooling material against the deposit so that the cooling layer conforms to the deposit. An additive manufacturing apparatus as described in any one of the appendices 1 to 3, characterized by the above. (Note 5) The cooling material nozzle dispenses the cooling material such that the direction of discharge of the cooling material is tangential to the deposit. An additive manufacturing apparatus as described in any one of the appendices 1 to 4, characterized by the above. (Note 6) The amount of pressure applied to the cooling material by the crimping roller is such that the cooling material does not break. The additive manufacturing apparatus described in Appendix 4, characterized by the features described herein. (Note 7) The cooling material is cooled before being delivered. An additive manufacturing apparatus as described in any one of the appendices 1 to 6, characterized by the above. (Note 8) The cooling gas used to cool the cooling material is the shielding gas used to cool the deposit. The additive manufacturing apparatus described in Appendix 7, characterized by the features described herein. (Note 9) The cooling material has a hollow shape, and a cooling gas or liquid is passed through the inside of the cooling layer. An additive manufacturing apparatus as described in any one of the appendices 1 to 8, characterized by the above. (Note 10) After the cooling layer is formed, the material nozzle delivers the additional material around the cooling layer, and the beam nozzle melts the additional material with the beam, thereby forming the deposit so that it comes into contact with the cooling layer during solidification. The additive manufacturing apparatus described in Appendix 1, characterized by the features described herein. (Note 11) The material nozzle performs a first dispensing step in which it delivers the additional material to the work surface, The irradiation step involves the beam nozzle irradiating the work surface with a beam that melts the added material, A second dispensing step in which a cooling material nozzle dispenses a cooling material having a lower melting point and higher thermal conductivity than the aforementioned additive material, Includes, As the deposit in which the added material has been melted solidifies, one layer of the deposit is stacked. The cooling layer formed from the cooling material is positioned so as to be in contact with the deposit during solidification. A structure is formed by stacking multiple layers of the aforementioned deposits. An additive manufacturing method characterized by the following: [Explanation of Symbols]

[0086] 1 Additive manufacturing equipment, 2 Chiller, 3 Laser oscillator, 4 Wire feeder, 5 Gas supplyer, 6 Control device, 11 Processing head, 12 Wire nozzle, 13 Beam nozzle, 14 Gas nozzle, 15 Moving stage, 16 Base plate, 17 Fiber cable, 18 Moving stage fixing part, 19, 72 Cooling material nozzle, 21 Wire, 31 Laser beam, 32 Shielding gas, 41 Manufactured object, 42 Processed surface, 43 Processed area, 44 Deposit, 61 Processing program, 62 CAD, 63 CAM, 71 Cooling material feeder, 73 Cooling material feed roller, 74 Cooling material crimping roller, 75 Crimping roller fixing device, 76 Cooling material cable, 78 Cooling material, 79, 79X Cooling layer, 81, 82 Nozzles.

Claims

1. A material nozzle that delivers additional material to the processing surface, A beam nozzle that irradiates the processed surface with a beam that melts the aforementioned additional material, A cooling material nozzle that dispenses a cooling material having a lower melting point and higher thermal conductivity than the aforementioned additive material, Equipped with, As the deposit in which the aforementioned additional material has been melted solidifies, one layer of the deposit is stacked. The cooling layer formed from the cooling material is positioned so as to be in contact with the deposit during solidification. A structure is formed by stacking multiple layers of the aforementioned deposits. An additive manufacturing apparatus characterized by the following features.

2. After the deposit is melted, the cooling material nozzle delivers the cooling material around the deposit so that the cooling layer is formed so that the solidifying deposit and the cooling layer come into contact. The additive manufacturing apparatus according to feature 1.

3. When one layer of the deposit is accumulated, the cooling material nozzle forms a cooling layer to the same height as one layer of the deposit. The additive manufacturing apparatus according to feature 1.

4. The system further comprises a pressure roller for pressing the cooling material onto the deposit as a cooling layer, The pressing roller presses the cooling material against the deposit so that the cooling layer conforms to the deposit. The additive manufacturing apparatus according to feature 1.

5. The cooling material nozzle dispenses the cooling material such that the direction of discharge of the cooling material is tangential to the deposit. The additive manufacturing apparatus according to feature 1.

6. The amount of pressure applied to the cooling material by the crimping roller is such that the cooling material does not break. The additive manufacturing apparatus according to feature 4.

7. The cooling material is cooled before being delivered. The additive manufacturing apparatus according to feature 1.

8. The cooling gas used to cool the cooling material is the shielding gas used to cool the deposit. The additive manufacturing apparatus according to feature 7.

9. The cooling material has a hollow shape, and a cooling gas or liquid is passed through the inside of the cooling layer. The additive manufacturing apparatus according to any one of claims 1 to 8.

10. After the cooling layer is formed, the material nozzle delivers the additional material around the cooling layer, and the beam nozzle melts the additional material with the beam, thereby forming the deposit so that it comes into contact with the cooling layer during solidification. The additive manufacturing apparatus according to feature 1.

11. The material nozzle performs a first dispensing step in which it dispenses the additional material to the processing surface, The irradiation step involves the beam nozzle irradiating the work surface with a beam that melts the added material, A second dispensing step in which a cooling material nozzle dispenses a cooling material having a lower melting point and higher thermal conductivity than the aforementioned additive material, Includes, As the deposit in which the aforementioned additional material has been melted solidifies, one layer of the deposit is stacked. The cooling layer formed from the cooling material is positioned so as to be in contact with the deposit during solidification. A structure is formed by stacking multiple layers of the aforementioned deposits. An additive manufacturing method characterized by the following:

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