Method for manufacturing heat exchanger and heat exchanger

Abstract

This method for manufacturing a heat exchanger 6 comprises: partially forming a second plate 92 by irradiation of a first beam b1 into a first irradiation area A1; and partially forming the second plate 92 by irradiation of a second beam b2 into a second irradiation area A2 that partially overlaps the first irradiation area A1. In an n-th layer, a cross section of the second plate 92 has a linear shape having a longitudinal direction d0. One end portion in the longitudinal direction d0 of a portion S1 of the second plate 92 formed by the first beam b1 includes a first connection portion C1 located in an area A3 where the first irradiation area A1 and the second irradiation area A2 overlap. One end portion in the longitudinal direction d0 of a portion S2 of the second plate 92 formed by the second beam b2 includes a second connection portion C2 located in the overlapping area A3 and connected to the first connection portion C1. The thickness t3 of at least one of the first connection portion C1 and the second connection portion C2 is larger than the thickness t2 of an adjacent portion 92b which is a portion of the second plate 92 formed by either the first beam b1 or the second beam b2 and which is adjacent to the overlapping area A3.

Description

Heat exchanger manufacturing method and heat exchanger

[0001] The technology disclosed herein relates to a method for manufacturing a heat exchanger and a heat exchanger.

[0002] For example, U.S. Patent No. 6,277,949 discloses a heat exchanger including multiple fluid passages manufactured by additive manufacturing, in which each layer is successively formed, for example, by melting or polymerizing plastic using beam energy or by sintering metal powder.

[0003] Special Publication No. 2020-509332

[0004] However, since the irradiation area of ​​a beam from one beam source is limited, additive manufacturing using multiple beam sources is considered in consideration of improving productivity, increasing the size of objects, etc. In this case, in an overlapping area where the irradiation areas of each beam overlap, an object is formed by both one beam and another beam. If the irradiation position of one beam and the irradiation position of another beam are misaligned in the overlapping area, there is a risk of defective fabrication.

[0005] The technology disclosed herein has been made in consideration of these points, and its purpose is to suppress the occurrence of defective molding.

[0006] The method for manufacturing a heat exchanger disclosed herein is a method for manufacturing a heat exchanger by additive manufacturing, which manufactures a heat exchanger having a plate that is a fin or a partition, and includes partially forming the plate by irradiating a first beam into a first irradiation area, and partially forming the plate by irradiating a second beam into a second irradiation area that partially overlaps with the first irradiation area, wherein in one layer, the cross section of the plate has a linear shape having a longitudinal direction, one end of the longitudinal direction of the portion of the plate formed by the first beam includes a first connecting portion located in an area where the first irradiation area and the second irradiation area overlap, and one end of the longitudinal direction of the portion of the plate formed by the second beam includes a second connecting portion located in the overlapping area and connected to the first connecting portion, and the thickness of at least one of the first connecting portion and the second connecting portion is greater than the thickness of an adjacent portion of the portion of the plate formed by either the first beam or the second beam and adjacent to the overlapping area.

[0007] Another aspect of a manufacturing method for a heat exchanger disclosed herein is a method for manufacturing a heat exchanger by additive manufacturing, which manufactures a heat exchanger having a plurality of plates, each of which is a fin or a partition wall, and includes forming one of the plurality of plates by either a first beam irradiated within a first irradiation area or a second beam irradiated within a second irradiation area that partially overlaps with the first irradiation area, and forming another of the plurality of plates by both the first beam and the second beam, wherein in one layer, the thickness of the other plate is greater than the thickness of the one plate.

[0008] The heat exchanger disclosed herein is a heat exchanger that is an additively formed body stacked in a stacking direction, and includes a plate that is a fin or a partition wall, the plate including a first portion and a second portion that is thicker than the first portion, each of the first portion and the second portion having a row of molten pool marks including a plurality of molten pool marks lined up in the stacking direction, and the number of rows of molten pool marks in the thickness direction in the second portion is greater than the number of rows of molten pool marks in the thickness direction in the first portion.

[0009] Another aspect of the heat exchanger disclosed herein is a heat exchanger that is an additively formed body stacked in a stacking direction, and is equipped with fins, the fins including a first portion and a second portion that is thicker than the first portion, each of the first portion and the second portion having a row of weld pool marks including a plurality of weld pool marks lined up in the stacking direction, the first portion having a single row of the weld pool marks in the thickness direction, and the second portion having a plurality of rows of the weld pool marks in the thickness direction.

[0010] Another aspect of the heat exchanger disclosed herein is a heat exchanger that is an additively formed body stacked in a stacking direction, and includes a plate that is a fin or a partition wall, the plate including a first portion and a second portion that is thicker than the first portion, and the crystal grain size of the second portion in a cross section parallel to both the thickness direction of the plate and the stacking direction is larger than the crystal grain size of the first portion in a cross section parallel to both the thickness direction of the plate and the stacking direction.

[0011] Another aspect of the heat exchanger disclosed herein is a heat exchanger that is an additively formed body stacked in a stacking direction, and includes a plate that is a fin or a partition wall, the plate including a first portion and a second portion that is thicker than the first portion, and the crystal grain size of the second portion in a cross section parallel to both the thickness direction of the plate and the stacking direction is smaller than the crystal grain size of the first portion in a cross section parallel to both the thickness direction of the plate and the stacking direction.

[0012] According to the method for manufacturing a heat exchanger, the occurrence of molding defects can be suppressed.

[0013] The heat exchanger can suppress the occurrence of molding defects.

[0014] FIG. 1 is a schematic diagram showing the configuration of an additive manufacturing apparatus. FIG. 2 is a schematic diagram of a heat exchanger. FIG. 3 is a schematic plan view of the interior of the heat exchanger viewed from the stacking direction. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3. FIG. 5 is a schematic plan view of the nth layer of fins and partition walls of the heat exchanger viewed from the stacking direction. FIG. 6 is a partially enlarged view of FIG. 5. FIG. 7 is an explanatory diagram for explaining a method for manufacturing a first plate. FIG. 8 is an explanatory diagram for explaining a method for manufacturing a second plate. FIG. 9 is an explanatory diagram for explaining a method for manufacturing a second plate. FIG. 10 is an explanatory diagram for explaining a method for manufacturing a second plate. FIG. 11 is an explanatory diagram for explaining a case where the irradiation position of the first beam and the irradiation position of the second beam are misaligned. FIG. 12 is a conceptual diagram for explaining a second method for increasing the thickness of at least one of the first and second connecting portions. FIG. 13 is a conceptual diagram for explaining a third method for increasing the thickness of at least one of the first and second connecting portions. FIG. 14 is a conceptual diagram illustrating a fourth method for increasing the thickness of at least one of the first connecting portion and the second connecting portion. FIG. 15 is a conceptual diagram illustrating a fifth method for increasing the thickness of at least one of the first connecting portion and the second connecting portion. FIG. 16 is a conceptual diagram illustrating a fifth method for increasing the thickness of at least one of the first connecting portion and the second connecting portion. FIG. 17 is a conceptual diagram illustrating a fifth method for increasing the thickness of at least one of the first connecting portion and the second connecting portion. FIG. 18 is a cross-sectional view taken along line XVIII-XVIII in FIG. 3. FIG. 19 is a cross-sectional view taken along line XIX-XIX in FIG. 3. FIG. 20 is a schematic plan view of the nth layer of a heat exchanger according to a modified example, viewed from the stacking direction. FIG. 21 is an explanatory diagram illustrating a method for manufacturing a first plate according to a modified example. FIG. 22 is an explanatory diagram illustrating a method for manufacturing a second plate according to a modified example. FIG. 23 is an explanatory diagram illustrating a method for manufacturing a second plate according to a modified example. FIG. 24 is an explanatory diagram illustrating a method for manufacturing a second plate according to a modified example. FIG. 25 is an explanatory diagram for explaining a case where the irradiation position of the first beam and the irradiation position of the second beam are misaligned.

[0015]

[0023] Exemplary embodiments will be described in detail below with reference to the accompanying drawings. The heat exchanger of the present disclosure is manufactured by additive manufacturing. First, an additive manufacturing apparatus will be described. Figure 1 is a schematic diagram showing the configuration of the additive manufacturing apparatus.

[0016] The additive manufacturing apparatus 100 includes a platform 11 on which raw material powder is placed, multiple beam sources 21, multiple scanners 4 that scan multiple beams from the multiple beam sources 21 over a powder bed 19 on the platform 11, and a control device 5 that controls the multiple scanners 4. The additive manufacturing apparatus 100 manufactures an object by scanning the multiple beams over the powder bed 19 to melt or sinter and solidify the powder material in the surface layer of the powder bed 19. For example, the additive manufacturing apparatus 100 performs layered manufacturing through additive manufacturing using powder bed fusion. Powder bed fusion is a manufacturing method in which raw material powder is spread on the platform 11, the raw material powder is melted or sintered by beams, and the solidified layers are stacked to form a shape.

[0017] The additive manufacturing apparatus 100 may further include a bed formation apparatus 1 that forms a powder bed 19. The platform 11 is included in the bed formation apparatus 1. In detail, the bed formation apparatus 1 has a platform 11 that can be raised and lowered, a partition wall 13 that defines a space that accommodates the platform 11, a supplier 14 that supplies raw material powder, and a recoater 15.

[0018] The partition wall 13 defines a space that is open upward. The platform 11 moves up and down in the space within the partition wall 13. A base plate 11a may be placed on the platform 11. Raw material powder is spread on the platform 11 and the base plate 11a.

[0019] The feeder 14 is disposed outside the partition wall 13. In this example, the feeder 14 feeds raw material powder to a position outside the partition wall 13. For example, the raw material powder may be a metal powder such as stainless steel, maraging steel, copper alloy, nickel alloy, titanium alloy, aluminum alloy, cobalt-chromium-molybdenum alloy, gold alloy, or platinum-based metallic glass. Alternatively, the raw material powder may be a resin powder such as polyamide (PA), filler-reinforced resin powder, polypropylene (PP), or polystyrene (PS). For example, the feeder 14 includes a partition wall 14a that defines a storage space for the raw material powder and a table 14b that can be raised and lowered within the partition wall 14a. The partition wall 14a is open upward. The raw material powder is placed on the table 14b. The feeder 14 raises the table 14b to discharge a portion of the raw material powder upward from the open end of the partition wall 14a. The feeder 14 may also be a hopper that supplies raw material powder.

[0020] The recoater 15 deposits powder material on the platform 11. The recoater 15 moves the raw material powder supplied from the supply device 14 onto the platform 11 and smoothes and levels the surface of the raw material powder on the platform 11. The recoater 15 reciprocates horizontally above the platform 11. The recoater 15 passes over the powder material supplied by the supply device 14 and also passes horizontally through the opening in the partition wall 13. In other words, the recoater 15 moves the powder material supplied by the supply device 14 onto the platform 11, spreads it over the platform 11, and further smoothes and levels the surface of the powder material on the platform 11.

[0021] The bed forming apparatus 1 is disposed in a chamber 16. The chamber 16 is filled with an inert gas. A gas supplier 17 is disposed in the chamber 16 to supply the inert gas into the chamber 16. For example, the inert gas is nitrogen gas, argon gas, or helium gas. By supplying the inert gas into the chamber 16, the oxygen concentration around the powder bed 19 can be reduced. More specifically, the gas supplier 17 flows the inert gas into the chamber 16 so as to generate a flow of the inert gas along the surface of the powder bed 19. In the example of FIG. 1 , the gas supplier 17 generates a flow of the inert gas along the surface of the powder bed 19 from the back side to the front side of the page.

[0022] The multiple beam sources 21 emit beams. In this example, the multiple beam sources 21 include a first beam source 21a and a second beam source 21b. The first beam source 21a emits a first beam b1, and the second beam source 21b emits a second beam b2. The first beam b1 is irradiated onto the powder bed 19 via the corresponding scanner 4. The second beam b2 is irradiated onto the powder bed 19 via the corresponding scanner 4. Hereinafter, when there is no need to distinguish between the first beam source 21a and the second beam source 21b, they will simply be referred to as "beam source 21."

[0023] In this example, the beam is laser light. The laser light may be a solid-state laser, a gas laser, or a semiconductor laser. In this case, the beam source 21 is a laser oscillator. The beam may also be an electron beam. In this case, the beam source 21 is an electron gun. The beam source 21 may be capable of changing at least one of the output and the spot diameter.

[0024] The multiple scanners 4 scan the beams emitted from the corresponding beam sources 21 over the powder bed 19. In this example, the scanners 4 include a first scanner 4a and a second scanner 4b. The first scanner 4a corresponds to the first beam source 21a, and the second scanner 4b corresponds to the second beam source 21b. Hereinafter, when there is no need to distinguish between the first scanner 4a and the second scanner 4b, they will be simply referred to as "scanners 4." The scanner 4 includes a galvanometer mirror 41. The galvanometer mirror 41 reflects the beam and irradiates the beam onto the powder bed 19. The galvanometer mirror 41 adjusts the reflection angle of the beam to move the irradiation point of the beam on the powder bed 19.

[0025] The control device 5 controls the bed formation device 1 in addition to the scanner 4. For example, the control device 5 causes the bed formation device 1 to form a powder bed 19, and causes the scanner 4 to scan the first beam b1 and the second beam b2 over the powder bed 19, thereby melting or sintering the raw material powder and solidifying it. The control device 5 repeats this process to manufacture an object.

[0026] Next, the heat exchanger 6 of the present disclosure will be described. Fig. 2 is a schematic diagram of the heat exchanger 6. In this example, the heat exchanger 6 is formed by additive manufacturing using powder bed fusion. That is, the heat exchanger 6 is an additively manufactured body stacked in a stacking direction X.

[0027] The heat exchanger 6 is a device for performing heat exchange between a first fluid f1 to be cooled and a second fluid f2 that cools the first fluid f1 via a partition wall. The properties of the first fluid f1 and the second fluid f2 are not particularly limited and include all combinations such as gas-gas mixtures, liquid-gas mixtures, and gas-liquid mixtures. The first fluid f1 and the second fluid f2 are, for example, water, oil, an organic medium, air, or helium gas.

[0028] In this example, the first fluid f1 is oil and the second fluid f2 is air. The first fluid f1 flows into the heat exchanger 6 from the inlet 62 and flows out from the outlet 63. The second fluid f2 flows into the heat exchanger 6 from one side and flows out from the other side of the heat exchanger 6.

[0029] 3 is a schematic plan view of the inside of the heat exchanger 6 as viewed from the stacking direction X. The heat exchanger 6 includes plates 9 that are fins 7 or partition walls 8. In this example, the heat exchanger 6 includes a plurality of plates 9, and the plurality of plates 9 includes both the fins 7 and the partition walls 8.

[0030] The partition wall 8 separates the first fluid f1 from the second fluid f2. The partition wall 8 defines a flow path for the first fluid f1. The partition wall 8 is plate-shaped and has a predetermined thickness. The thickness of the partition wall 8 is, for example, 0.5 mm or more and 5.0 mm or less.

[0031] The fins 7 increase the contact area of ​​the heat exchanger 6 with the second fluid f2. The fins 7 are plate-shaped and have a predetermined thickness. The thickness of the fins 7 is, for example, 0.1 mm or more and 1.0 mm or less. The fins 7 are connected to the partition walls 8. In this example, a plurality of fins 7 are connected to the partition walls 8. The plurality of fins 7 include a first fin 71, a second fin 72, a third fin 73, and a fourth fin 74. Hereinafter, when there is no need to distinguish between the first fin 71, the second fin 72, the third fin 73, and the fourth fin 74, they will be simply referred to as "fins 7."

[0032] As described above, the first fluid f1 flows through the flow paths defined by the partition walls 8. The second fluid f2 flows around the partition walls 8 and the fins 7. As a result, heat exchange occurs between the first fluid f1 and the second fluid f2 via the partition walls 8 and the fins 7. At this time, the fins 7 increase the contact area of ​​the heat exchanger 6 with the second fluid f2, thereby improving the efficiency of heat exchange.

[0033] In additive manufacturing, the plate 9 is formed by at least one of the first beam b1 and the second beam b2. More specifically, the plate 9 is formed by forming an object having a longitudinal shape, i.e., a linear object, using at least one of the first beam b1 and the second beam b2, and stacking the object in layers. In FIG. 3, for convenience of explanation, the first irradiation area A1, which is the irradiation area of ​​the first beam b1, is depicted by a dashed line, and the second irradiation area A2, which is the irradiation area of ​​the second beam b2, is depicted by a dashed double-dashed line. This also applies to FIGS. 4, 5, 6, and 20 described below. The second irradiation area A2 partially overlaps with the first irradiation area A1. Hereinafter, the area where the first irradiation area A1 and the second irradiation area A2 overlap is referred to as the "overlap area A3." The diameters of the first irradiation area A1 and the second irradiation area A2 are, for example, 200 mm or more and 500 mm or less.

[0034] In this example, the partition 8, the first fin 71, and the fourth fin 74 are each formed by only the first beam b1. That is, the partition 8, the first fin 71, and the fourth fin 74 are each formed by the first beam b1 irradiated onto an area of ​​the first irradiation area A1 excluding the overlap area A3. Hereinafter, the plate 9 formed by only either the first beam b1 or the second beam b2 will be referred to as the "first plate 91."

[0035] The second fin 72 and the third fin 73 are each formed by both the first beam b1 and the second beam b2. In this example, the second fin 72 and the third fin 73 are each formed by the first beam b1 and the second beam b2 irradiated to the area of ​​the first irradiation area A1 excluding the overlapping area A3, the area of ​​the second irradiation area A2 excluding the overlapping area A3, and the overlapping area A3. Hereinafter, the plate 9 formed by both the first beam b1 and the second beam b2 will be referred to as the "second plate 92." The second plate 92 is an example of a plate disclosed herein.

[0036] The second plate 92 includes an overlapping portion 92a located in the overlapping area A3. In this example, the second plate 92 is partially formed by irradiation of the first beam b1 into the first irradiation area A1 and partially formed by irradiation of the second beam b2 into the second irradiation area A2. That is, the overlapping portion 92a is formed in a part of the second plate 92.

[0037] Specifically, the second plate 92 includes a first portion P1 and a second portion P2 that is thicker than the first portion P1. The second portion P2 is formed in at least a portion of the overlapping portion 92a. That is, in the present disclosure, the thickness of at least a portion of the second plate 92 that is located in the overlapping area A3 is made larger than the thickness of the portions of the first irradiation area A1 and the second irradiation area A2 that are located in the area excluding the overlapping area A3.

[0038] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3 . Specifically, FIG. 4 is a cross-sectional view of the partition wall 8 and the second plate 92 cut along a plane perpendicular to the thickness direction of the second plate 92 (specifically, the second fin 72) and passing through the center of the thickness direction. The second plate 92 includes layers from the first layer, which is the lowest layer, to the Nth layer, which is the highest layer (N: natural number). At least one of the first to Nth layers includes a portion of an overlapping portion 92a. In this example, the width of the second plate 92 in a direction perpendicular to both the stacking direction X and the thickness direction narrows from the bottom layer to the top layer. While the nth layer (n: natural number, 1<n<N) of the second plate 92 includes the overlapping portion 92a, for example, the Nth layer of the second plate 92 does not include the overlapping portion 92a. The Nth layer of the second plate 92 is formed only by the first laser. Thus, depending on the shape of the second plate 92, some layers of the second plate 92 may not include the overlapping portion 92a.

[0039] 5 is a schematic plan view of the nth layer of the fins 7 and partition walls 8 of the heat exchanger 6 as viewed from the stacking direction X. In the nth layer, the second plate 92 includes an adjacent portion 92b that is formed by either the first beam b1 or the second beam b2 of the second plate 92 and that is adjacent to the overlapping area A3. The length L of the adjacent portion 92b in a direction perpendicular to both the thickness direction and the stacking direction X (hereinafter referred to as the "length direction") is, for example, 10 mm.

[0040] FIG. 6 is a partial enlarged view of FIG. 5 . In the nth layer, the thickness t1 of at least a portion of the overlapping portion 92a is greater than the thickness t2 of the adjacent portion 92b. For example, the thickness t1 is 1.5 to 3 times the thickness t2. The second portion P2 is formed by stacking the relatively thick portions of the overlapping portion 92a. At least a portion of the first portion P1 is formed by stacking the adjacent portions 92b. For example, the thickness t1 is the average thickness of the overlapping portion 92a in the longitudinal direction. For example, the thickness t2 is the average thickness of the adjacent portions 92b in the longitudinal direction. In this example, in the second fin 72, the thickness t1 of the entire overlapping portion 92a in the longitudinal direction is greater than the thickness t2 of the adjacent portion 92b. In the third fin 73, the thickness t1 of a portion of the overlapping portion 92a is greater than the thickness t2 of the adjacent portion 92b.

[0041] Next, a method for manufacturing the heat exchanger 6 will be described. The method for manufacturing the heat exchanger 6 includes forming an object having a shape with a longitudinal direction by scanning a beam over a powder bed 19. The method for manufacturing the heat exchanger 6 may further include forming the powder bed 19 by spreading raw material powder on the platform 11.

[0042] 1, first, the supply device 14 raises the table 14b to discharge a portion of the raw material powder upward from the open end of the partition wall 14a. Next, the recoater 15 moves the raw material powder supplied from the supply device 14 onto the platform 11 and smoothes and levels the surface of the raw material powder on the platform 11. In this way, the raw material powder is spread all over the platform 11, forming a powder bed 19.

[0043] Next, a beam is scanned across the powder bed 19 to form an object. More specifically, the first beam source 21a is turned on to emit a first beam b1. The first beam b1 emitted from the first beam source 21a is irradiated onto the powder bed 19 via the scanner 4a. The scanner 4a is controlled by the control device 5, and the first beam b1 is scanned across the powder bed 19. This melts or sinters the raw material powder, solidifying it and forming a first layer of object corresponding to the first beam b1. Similarly, the second beam source 21b is turned on to emit a second beam b2. The second beam b2 emitted from the second beam source 21b is irradiated onto the powder bed 19 via the scanner 4b. The scanner 4b is controlled by the control device 5, and the second beam b2 is scanned across the powder bed 19. This melts or sinters the raw material powder, solidifying it and forming a first layer of object corresponding to the second beam b2. Next, the platform 11 is lowered by the thickness of one layer. Next, the supplier 14 raises the table 14b, discharging a portion of the raw material powder upward from the open end of the partition wall 14a. Next, the recoater 15 moves the raw material powder supplied from the supplier 14 onto the platform 11, and supplies the raw material powder for the next layer into the vacant space on the platform 11. As a result, the raw material powder for the next layer is spread on the platform 11, forming a powder bed 19 for the next layer. Next, as with the first layer, the first beam b1 and the second beam b2 are scanned over the powder bed 19 for the next layer, forming a second layer of the object. The process of spreading the raw material powder on the platform 11 to form the powder bed 19 and scanning the beams over the powder bed 19 to form one layer of the object is repeated up to the Nth layer, thereby manufacturing the heat exchanger 6. Furthermore, after irradiating the powder bed 19 with either the first beam b1 or the second beam b2, the other of the first beam b1 or the second beam b2 may be irradiated, or the powder bed 19 may be irradiated with the first beam b1 and the second beam b2 simultaneously.

[0044] Scanning the beam across the powder bed 19 to form the object includes forming a first plate 91 and forming a second plate 92. Forming the second plate 92 includes partially forming the second plate 92 by irradiating a first irradiation area A1 with a first beam b1 and partially forming the second plate 92 by irradiating a second irradiation area A2 with a second beam b2.

[0045] First, a method for manufacturing the first plate 91 will be described. Fig. 7 is an explanatory diagram for explaining the method for manufacturing the first plate 91. In detail, Fig. 7 is a schematic plan view as viewed from the stacking direction X. The same applies to Figs. 8, 9, 10, and 11 described below.

[0046] The first plate 91 is formed using only either the first beam b1 or the second beam b2. In this example, the first plate 91 is formed using only the first beam b1. First, in the layer to be formed in the first plate 91, the first beam b1 is scanned across the powder bed 19 in the first irradiation area A1 excluding the overlap area A3. The above process is repeated from the first layer to the Nth layer, thereby manufacturing the first plate 91.

[0047] Next, a method for manufacturing the second plate 92 will be described. Figures 8, 9, and 10 are explanatory diagrams for explaining the method for manufacturing the second plate 92. In detail, Figure 8 is an explanatory diagram for explaining the method for manufacturing the portion of the second plate 92 formed by the first beam b1. Figure 9 is an explanatory diagram for explaining the method for manufacturing the portion of the second plate 92 formed by the second beam b2. Figure 10 is an explanatory diagram for explaining the formed second plate 92.

[0048] The second plate 92 is formed by both the first beam b1 and the second beam b2. If the layer to be formed in the second plate 92 does not include a portion to be placed in the overlap area A3, the first beam b1 or the second beam b2 is scanned over the powder bed 19 in the first irradiation area A1 or the second irradiation area A2 excluding the overlap area A3, as in the first plate 91. This forms the target layer in the second plate 92.

[0049] When the layer to be formed in the second plate 92 includes a portion to be placed in the overlap area A3, as shown in FIG. 8 , the first beam b1 is scanned across the powder bed 19 in the first irradiation area A1, which includes the overlap area A3. This forms a portion S1 of the layer to be formed in the second plate 92, which corresponds to the first beam b1. Next, as shown in FIG. 9 , the second beam b2 is scanned across the powder bed 19 in the second irradiation area A2, which includes the overlap area A3. This forms a portion S2 of the layer to be formed in the second plate 92, which corresponds to the second beam b2. As shown in FIG. 10 , in the layer to be formed in the second plate 92, part or all of the portions S1 and S2 overlap each other. This forms the layer to be formed in the second plate 92.

[0050] As shown in FIG. 8 , one longitudinal end of portion S1 includes a first connecting portion C1 located in overlapping area A3. The first connecting portion C1 is a portion of portion S1 that overlaps with portion S2 in the longitudinal direction. A longitudinally overlapping portion is not limited to a portion where the components actually overlap, but also includes a portion where the longitudinal positions overlap (the same applies below). In other words, the first connecting portion C1 is a portion of portion S1 that extends from a position corresponding to one longitudinal end of portion S2 to one longitudinal end of portion S1. The first connecting portion C1 is at least a portion of the overlapping portion 92a described above. In this example, the first connecting portion C1 is a portion of the overlapping portion 92a described above.

[0051] Similarly, as shown in FIG. 9 , one longitudinal end of portion S2 includes a second connecting portion C2 located in overlapping area A3. The second connecting portion C2 is a portion of portion S2 that overlaps with portion S1 in the longitudinal direction. That is, the second connecting portion C2 is a portion of portion S2 that extends from a position corresponding to one longitudinal end of portion S1 to one longitudinal end of portion S2. The second connecting portion C2 is at least a portion of the overlapping portion 92a described above. In this example, the second connecting portion C2 is a portion of the overlapping portion 92a described above.

[0052] As shown in FIG. 10 , the first connecting portion C1 and the second connecting portion C2 are at least partially overlapping and connected. In the present disclosure, the thickness of at least one of the first connecting portion C1 and the second connecting portion C2 is greater than the thickness of the adjacent portion 92b. In this example, as shown in FIG. 9 , the thickness t3 of the second connecting portion C2 is greater than the thickness t2 of the adjacent portion 92b. The thickness t3 is, for example, the average thickness in the longitudinal direction d0. As shown in FIG. 11 , because the thickness t3 of the second connecting portion C2 is greater than the thickness t2 of the adjacent portion 92b, even if the irradiation positions of the first beam b1 and the second beam b2 are misaligned, the first connecting portion C1 and the second connecting portion C2 can be partially overlapped and connected, thereby preventing defective molding. FIG. 11 is an explanatory diagram for describing a case where the irradiation positions of the first beam b1 and the second beam b2 are misaligned.

[0053] If the target layer includes a portion that is to be arranged in the overlapping area A3 as well as a portion that is to be arranged in the area of ​​the first irradiation area A1 excluding the overlapping area A3, the corresponding portion is formed by irradiation with the first beam b1. If the target layer includes a portion that is to be arranged in the area of ​​the second irradiation area A2 excluding the overlapping area A3 as well as a portion that is to be arranged in the overlapping area A3, the corresponding portion is formed by irradiation with the second beam b2.

[0054] The above process is repeated from the first layer to the Nth layer to form the second plate 92. In this way, the second plate 92 is partially formed by irradiating the first irradiation area A1 with the first beam b1, and the second plate 92 is partially formed by irradiating the second irradiation area A2 with the second beam b2. In the overlap area A3, a portion of the second plate 92 is formed by irradiating both the first beam b1 and the second beam b2.

[0055] Next, a first to seventh methods for making the thickness of at least one of the first connecting portion C1 and the second connecting portion C2 greater than the thickness of the adjacent portion 92 b will be described. To make the thickness of at least one of the first connecting portion C1 and the second connecting portion C2 greater than the thickness of the adjacent portion 92 b, for example, at least one of the first beam b1 forming the first connecting portion C1 and the second beam b2 forming the second connecting portion C2 is scanned in a direction intersecting the longitudinal direction d0 of the target linear object within the overlap area A3, while scanning the entire object in the longitudinal direction d0.

[0056] Specifically, in the first method, the beam output of at least one of the first beam b1 forming the first connecting portion C1 and the second beam b2 forming the second connecting portion C2 is set to be greater than the beam output of the first beam b1 or the second beam b2 forming the adjacent portion 92 b. In the example shown in Fig. 10, the beam output of the second beam b2 forming the second connecting portion C2 is set to be greater than the beam output of the first beam b1 and the second beam b2 forming the adjacent portion 92 b.

[0057] FIG. 12 is a conceptual diagram illustrating a second method for increasing the thickness of at least one of the first connecting portion C1 and the second connecting portion C2. FIG. 12 illustrates a beam scanning method. The block arrow in the figure indicates the longitudinal direction d0 of the linear object in the target layer, which is the overall scanning direction of the beam. The solid arrow in the figure indicates the beam scanning direction. In this example, the beam scanning direction in the first irradiation area A1 is approximately parallel to the longitudinal direction d0. This also applies to FIGS. 13, 14, 15, 16, and 17, which will be described later. In the second method, at least one of the first beam b1 forming the first connecting portion C1 and the second beam b2 forming the second connecting portion C2 is scanned in a zigzag pattern in the longitudinal direction d0 within the overlap area A3, specifically, the powder bed 19 within the overlap area A3. That is, in the second method, the beam scanning path is a repeated return of a linear path inclined relative to the longitudinal direction d0.

[0058] FIG. 13 is a conceptual diagram illustrating a third method for increasing the thickness of at least one of the first connecting portion C1 and the second connecting portion C2. FIG. 14 is a conceptual diagram illustrating a fourth method for increasing the thickness of at least one of the first connecting portion C1 and the second connecting portion C2. In the third and fourth methods, at least one of the first beam b1 forming the first connecting portion C1 and the second beam b2 forming the second connecting portion C2 is repeatedly scanned alternately in a first direction d1 intersecting the longitudinal direction d0 and a second direction d2 opposite to the first direction d1 while changing its position in the longitudinal direction d0. In this example, at least one of the first beam b1 forming the first connecting portion C1 and the second beam b2 forming the second connecting portion C2 is scanned in the first direction d1, then the beam irradiation position is moved in the longitudinal direction d0 with the beam turned off, then the beam is scanned in the second direction d2, and then the beam irradiation position is moved in the longitudinal direction d0 with the beam turned off. This process is repeated in sequence. As shown in Fig. 13, in the third method, the first direction d1 is substantially perpendicular to the longitudinal direction d0. As shown in Fig. 14, in the fourth method, the first direction d1 is not perpendicular to the longitudinal direction d0 but is inclined.

[0059] 15 is a conceptual diagram illustrating a fifth method for increasing the thickness of at least one of the first connecting portion C1 and the second connecting portion C2. In the fifth method, at least one of the first beam b1 forming the first connecting portion C1 and the second beam b2 forming the second connecting portion C2 is repeatedly scanned alternately in a first direction d1 intersecting the longitudinal direction d0 and a second direction d2 intersecting both the longitudinal direction d0 and the first direction d1 while changing its position in the longitudinal direction d0. In this example, at least one of the first beam b1 forming the first connecting portion C1 and the second beam b2 forming the second connecting portion C2 is scanned in the first direction d1 intersecting the longitudinal direction d0, then, with the beam turned off, the beam irradiation position is moved in the direction opposite the longitudinal direction d0, then, with the beam turned off, the beam is scanned in the second direction d2 intersecting both the longitudinal direction and the first direction d1, and then, with the beam turned off, the beam irradiation position is moved in the direction opposite the longitudinal direction d0. This process is repeated in sequence.

[0060] 16 is a conceptual diagram illustrating a sixth method for increasing the thickness of at least one of the first connecting portion C1 and the second connecting portion C2. In the sixth method, scanning is performed in a direction intersecting the longitudinal direction d0 with at least one of the first beam b1 forming the first connecting portion C1 and the second beam b2 forming the second connecting portion C2, while repeatedly changing the position in the longitudinal direction d0. In this example, scanning is performed in a first direction d1 intersecting the longitudinal direction d0 with at least one of the first beam b1 forming the first connecting portion C1 and the second beam b2 forming the second connecting portion C2, and then, with the beam turned off, the beam irradiation position is moved in a second direction intersecting the longitudinal direction d0, and this process is repeated in sequence.

[0061] 17 is a conceptual diagram illustrating a seventh method for increasing the thickness of at least one of the first connecting portion C1 and the second connecting portion C2. In the seventh method, a scan P in the longitudinal direction d0 by at least one of the first beam b1 forming the first connecting portion C1 and the second beam b2 forming the second connecting portion C2 is performed multiple times while changing the position in the thickness direction. In this example, the scan P is performed twice while changing the position in the thickness direction.

[0062] Next, the cross-sectional microstructures of the first portion P1 and the second portion P2 formed by the aforementioned manufacturing method will be described. FIG. 18 is a cross-sectional view taken along line XVIII-XVIII in FIG. 3. Specifically, FIG. 18 is a cross-sectional view of the first portion P1 of the third fin 73 cut along a plane parallel to both the thickness direction and the stacking direction X. FIG. 19 is a cross-sectional view taken along line XIX-XIX in FIG. 3. Specifically, FIG. 19 is a cross-sectional view of the second portion P2 of the third fin 73 cut along a plane parallel to both the thickness direction and the stacking direction X. Note that FIG. 19 is an example of a cross-section of the second portion P2 formed by the aforementioned seventh method.

[0063] 18 and 19 , each of the first portion P1 and the second portion P2 has a weld pool trace row 93R including a plurality of weld pool traces 93 aligned in the stacking direction X. The weld pool traces 93 are traces of a weld pool formed by melting the raw material powder and solidifying.

[0064] The number of rows of weld pool marks 93R in the thickness direction in the second portion P2 is greater than the number of rows of weld pool marks 93R in the thickness direction in the first portion P1. Here, one weld pool mark 93 is formed by one beam scan. The number of rows of weld pool marks 93R in the thickness direction roughly indicates the number of beam scans in one layer. For example, if the number of rows of weld pool marks 93R in the thickness direction in the second portion P2 is two, this roughly indicates that the second portion P2 was formed by two beam scans. Therefore, the above-mentioned magnitude relationship of the number of rows of weld pool marks 93R indicates that the number of beam scans in the second portion P2 is greater than the number of beam scans in the first portion P1 in one layer.

[0065] In this example, as shown in Fig. 18 , the first portion P1 of the third fin 73 has one row of weld pool marks 93R in the thickness direction. That is, the first portion P1 of the third fin 73 is formed by one beam scan in one layer. As shown in Fig. 19 , the second portion P2 of the third fin 73 has multiple rows of weld pool marks 93R in the thickness direction. Specifically, the second portion P2 of the third fin 73 has two rows of weld pool marks 93R in the thickness direction. That is, the second portion P2 of the third fin 73 is formed by two beam scans in one layer.

[0066] Furthermore, the crystal grain size of the second portion P2 in a cross section parallel to both the thickness direction and the stacking direction X of the plate is larger than the crystal grain size of the first portion P1 in a cross section parallel to both the thickness direction and the stacking direction X of the plate. The crystal grain size is measured, for example, using electron backscatter diffraction (EBSD). The measurement conditions for electron backscatter diffraction are preferably, for example, a pixel size of less than 1 μm and a viewing area of ​​500 μm × 500 μm. However, if the thickness of the plate 9 is too thin to ensure the viewing area, the size of the viewing area in the stacking direction may be 500 μm, and the size of the viewing area in the thickness direction may be 100 μm to 500 μm depending on the thickness of the plate 9. In determining crystal grains, boundaries with a crystal orientation difference of 15° or more may be determined to be crystal grain boundaries. The crystal grain size may be, for example, the volume average grain size of the crystals in the observed image.

[0067] As a method for making the crystal grain size of the second portion P2 larger than that of the first portion P1, for example, the timing of irradiation of the first beam b1 and the timing of irradiation of the second beam b2 onto the powder bed 19 can be approximately matched, or the beam output in the second portion can be made larger than the beam output in the first portion, thereby making the crystal grain size of the second portion P2 larger than that of the first portion P1.

[0068] In this heat exchanger 6, the second plate 92 has a second portion P2 that is thicker than the first portion P1. The number of rows of molten pool marks 93R in the thickness direction in the second portion P2 is greater than the number of rows of molten pool marks 93R in the thickness direction in the first portion P1. Furthermore, the crystal grain size of the second portion P2 in a cross section parallel to both the thickness direction and the stacking direction X of the plate is larger than the crystal grain size of the first portion P1 in a cross section parallel to both the thickness direction and the stacking direction X of the plate. That is, the second portion P2 is formed by scanning multiple beams. Because the second portion P2 has a relatively large thickness, even if misalignment occurs between the irradiation positions of each beam, the objects formed by each beam can be connected to each other. This suppresses molding defects in the second portion, thereby realizing a heat exchanger 6 with suppressed molding defects. Furthermore, because the crystal grain size of the second portion P2 is larger than the crystal grain size of the first portion P1, the thermal conductivity of the second portion P2 can be higher than that of the first portion P1.

[0069] In particular, in this example, the first portion P1 of the third fin 73 has one row of weld pool marks 93R in the thickness direction, and the second portion P2 of the third fin 73 has two rows of weld pool marks 93R in the thickness direction. This makes it possible to minimize the thickness of the first portion P1 while suppressing the occurrence of molding defects in the second portion P2.

[0070] Furthermore, according to the above-described manufacturing method, the thickness t3 of at least one of the first connecting portion C1 of the portion S1 of the second plate 92 formed by the first beam b1 and the second connecting portion C2 of the portion S2 of the second plate 92 formed by the second beam b2 is greater than the thickness t2 of the adjacent portion 92b. Therefore, even if there is a misalignment between the irradiation position of the first beam b1 and the irradiation position of the second beam b2 within the overlapping area A3, the first connecting portion C1 and the second connecting portion C2 are connected, thereby suppressing the occurrence of defective molding within the overlapping area A3. As a result, the occurrence of defective molding of the manufactured heat exchanger 6 can also be suppressed.

[0071] Next, a heat exchanger according to a modified example will be described. Fig. 20 is a schematic plan view of the nth layer of a heat exchanger 206 according to a modified example, viewed from the stacking direction X. The heat exchanger 206 differs from the heat exchanger 6 in the thickness configuration of the second plate 292. Since the other configurations are the same as those of the heat exchanger 6, detailed description will be omitted.

[0072] In the nth layer, the thickness t4 of the second plate 292 is greater than the thickness t5 of the first plate 91. The first plate 91 is an example of "one plate" in the present disclosure. The second plate 292 is an example of "another plate" in the present disclosure. The thickness t4 is the average thickness of the second plate 292 in the longitudinal direction. The thickness t5 is the average thickness of the first plate 91 in the longitudinal direction. In this example, the second plate 292 has a substantially uniform thickness in the longitudinal direction. That is, in this example, the thickness of the second plate 292 is relatively large throughout the entire longitudinal direction, including the adjacent portion 292b.

[0073] Next, a description will be given of a manufacturing method of the heat exchanger 206. The manufacturing method of the heat exchanger 206 includes forming a first plate 91 using either the first beam b1 or the second beam b2, and forming a second plate 292 using both the first beam b1 and the second beam b2.

[0074] FIG. 21 is an explanatory diagram for explaining a method of forming the first plate 91. More specifically, FIG. 21 is a schematic plan view viewed from the stacking direction X. The same applies to FIGS. 22, 23, 24, and 25 described below. The first plate 91 is formed using only one of the first beam b1 and the second beam b2. In this example, the first plate 91 is formed using only the first beam b1. First, in the layer to be formed of the first plate 91, the first beam b1 is scanned over the powder bed 19 in the first irradiation area A1 excluding the overlap area A3. The above process is repeated from the first layer to the Nth layer to manufacture the first plate 91.

[0075] 22, 23, and 24 are explanatory diagrams for explaining a manufacturing method of the second plate 292. In detail, FIG. 22 is an explanatory diagram for explaining a manufacturing method of the portion of the second plate 292 formed by the first beam b1. FIG. 23 is an explanatory diagram for explaining a manufacturing method of the portion of the second plate 292 formed by the second beam b2. FIG. 24 is an explanatory diagram for explaining the formed second plate 292.

[0076] The second plate 292 is formed by both the first beam b1 and the second beam b2. If the layer to be formed in the second plate 292 does not include a portion to be placed in the overlap area A3, the first beam b1 or the second beam b2 is scanned over the powder bed 19 in the first irradiation area A1 or the second irradiation area A2 excluding the overlap area A3, as in the first plate 91. This forms the layer to be formed in the second plate 292.

[0077] When the layer to be formed in the second plate 292 includes a portion to be placed in the overlap area A3, as shown in FIG. 22 , the first beam b1 is scanned across the powder bed 19 in the first irradiation area A1, which includes the overlap area A3. This forms a portion S1 of the layer to be formed in the second plate 292, corresponding to the first beam b1. At this time, the thickness of the portion S1 is set to be greater than the thickness of the first plate 91. Next, as shown in FIG. 23 , the second beam b2 is scanned across the powder bed 19 in the second irradiation area A2, which includes the overlap area A3. This forms a portion S2 of the layer to be formed in the second plate 292, corresponding to the second beam b2. As shown in FIG. 24 , in the layer to be formed in the second plate 292, the portions S1 and S2 partially or entirely overlap each other. 25 , since the thickness of both the portion S1 and the portion S2 is greater than the thickness of the first plate 91, even if the irradiation position of the first beam b1 and the irradiation position of the second beam b2 are misaligned, the portions S1 and S2 can be connected, thereby preventing defective molding. Fig. 25 is an explanatory diagram for explaining a case where the irradiation position of the first beam b1 and the irradiation position of the second beam b2 are misaligned. The above process is repeated from the first layer to the Nth layer to form the second plate 292.

[0078] In this heat exchanger 206, in the nth layer, the thickness t4 of the second plate 292 is greater than the thickness t5 of the first plate 91. Therefore, even if a misalignment occurs between the irradiation position of the first beam b1 and the irradiation position of the second beam b2 during manufacturing of the overlapping portion 292a of the second plate 292, the occurrence of defective molding of the overlapping portion 292a is suppressed. As a result, the occurrence of defective molding of the heat exchanger 206 can also be suppressed.

[0079] Furthermore, according to the above-described manufacturing method, the thickness t4 of the entire second plate 292 including the overlapping portion 292a can be made larger than the thickness t5 of the first plate 91. Therefore, even if there is a misalignment between the irradiation position of the first beam b1 and the irradiation position of the second beam b2 within the overlapping area A3, the occurrence of defective molding of the overlapping portion 292a is suppressed. As a result, the occurrence of defective molding of the manufactured heat exchanger 6 can also be suppressed.

[0080] Other Embodiments As described above, the above-described embodiments have been described as examples of the technology disclosed in the present application. However, the technology of the present disclosure is not limited to these embodiments and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made as appropriate. Furthermore, the components described in the above-described embodiments can be combined to create new embodiments. Furthermore, the components described in the accompanying drawings and detailed description may include not only components essential for solving the problem, but also components that are not essential for solving the problem in order to exemplify the technology. Therefore, the fact that these non-essential components are described in the accompanying drawings or detailed description should not be interpreted as immediately determining that these non-essential components are essential.

[0081] For example, the additive manufacturing apparatus 100 may be equipped with three or more beam sources 21. In this case, the arrangement of the irradiation areas of the beams emitted from each beam source relative to the powder bed 19 is not limited.

[0082] The heat exchangers 6 and 206 may include only one of the fins 7 and the partition walls 8 .

[0083] In the above-described example, the second fins 72, 272 and the third fins 73, 273 are the second plates 92, 292, but the partition wall 8 may be the second plate. That is, the partition wall 8 may be formed by both the first beam b1 and the second beam b2, and the thickness of the overlapping portion of the partition wall 8 may be relatively large.

[0084] The shape, number, and arrangement of the first plates 91 are not limited. The number and arrangement of the second plates 92 are not limited. The shape of the second plates 92, 292 is not limited other than the thickness configuration described above. For example, the shape of the second plates 92, 292 in the length direction may be linear, curved, or branched. For example, the cross-sectional shape when the second plate 92 is cut along a plane passing through the center of the second plate 92, 292 in the thickness direction may simply be rectangular.

[0085] The number of rows of weld pool marks 93R in the thickness direction in the first portion P1 may be two or more. The number of rows of weld pool marks 93R in the thickness direction in the second portion P2 may be three or more.

[0086] The crystal grain size of the second portion P2 in a cross section parallel to both the thickness direction and the stacking direction X of the second plate 92 may be smaller than the crystal grain size of the first portion P1 in a cross section parallel to both the thickness direction and the stacking direction X of the second plate 92. This allows the strength of the second portion P2 to be greater than the strength of the first portion P1. For example, when manufacturing the second portion P2, the crystal grain size of the second portion P2 can be made smaller than the crystal grain size of the first portion P1 by shifting the irradiation timing of the first beam b1 and the irradiation timing of the second beam b2 by a predetermined time or by setting the beam output in the second portion smaller than the beam output in the first portion.

[0087] 12, 13, 14, 15, 16, and 17, the beam scanning direction in the first irradiation area A1 is substantially parallel to the longitudinal direction d0, but the beam scanning direction in the first irradiation area A1 does not have to be substantially parallel to the longitudinal direction d0. For example, the beam in the first irradiation area A1 may be scanned in the same manner as the beam in the overlapping area A3. In this case, the width of the beam scanning path in the first irradiation area A1 in the direction perpendicular to the longitudinal direction d0 is smaller than the width of the beam scanning path in the overlapping area A3 in the direction perpendicular to the longitudinal direction d0.

[0088] In the manufacturing method of the heat exchanger 6, the thickness t3 of both the first connecting portion C1 and the second connecting portion C2 may be greater than the thickness t2 of the adjacent portion 92b, or the thickness t3 of the second connecting portion C2 may be approximately the same as the thickness t2 of the adjacent portion 92b, and the thickness of the first connecting portion C1 may be greater than the thickness t2 of the adjacent portion 92b.

[0089] [Aspects] The above-described embodiments are specific examples of the following aspects.

[0090] (Aspect 1) A manufacturing method of a heat exchanger 6 is a manufacturing method of a heat exchanger 6 that manufactures a heat exchanger 6 including a plate (second plate 92) that is a fin 7 or a partition wall 8 by additive manufacturing, the manufacturing method of the heat exchanger 6 including: partially forming the plate (second plate 92) by irradiating a first irradiation area A1 with a first beam b1; and partially forming the plate (second plate 92) by irradiating a second irradiation area A2 that partially overlaps with the first irradiation area A1 with a second beam b2; in one layer (n-th layer), a cross section of the plate (second plate 92) has a linear shape having a longitudinal direction d0, and the longitudinal direction of a portion S1 of the plate (second plate 92) formed by the first beam b1 is One end of d0 includes a first connecting portion C1 located in area A3 where the first irradiation area A1 and the second irradiation area A2 overlap, and one end of the longitudinal direction d0 of portion S2 of the plate (second plate 92) formed by the second beam b2 includes a second connecting portion C2 located in the overlapping area A3 and connected to the first connecting portion C1, and a thickness t3 of at least one of the first connecting portion C1 and the second connecting portion C2 is greater than a thickness t2 of an adjacent portion 92b of the plate (second plate 92) formed by either the first beam b1 or the second beam b2 and adjacent to the overlapping area A3.

[0091] With this configuration, the thickness t3 of at least one of the first connecting portion C1 and the second connecting portion C2 is greater than the thickness t2 of the adjacent portion 92b, so that even if there is a misalignment between the irradiation position of the first beam b1 and the irradiation position of the second beam b2 within the overlapping area A3, the first connecting portion C1 and the second connecting portion C2 are connected, thereby suppressing the occurrence of defective molding within the overlapping area A3. As a result, the occurrence of defective molding of the manufactured heat exchanger 6 can also be suppressed.

[0092] (Aspect 2) In the manufacturing method of the heat exchanger 6 described in aspect 1, the beam output of at least one of the first beam b1 forming the first connecting portion C1 and the second beam b2 forming the second connecting portion C2 is made larger than the beam output of the first beam b1 or the second beam b2 forming the adjacent portion 92b, thereby making the thickness t3 of at least one of the first connecting portion C1 and the second connecting portion C2 larger than the thickness t2 of the adjacent portion 92b.

[0093] According to this configuration, it is possible to realize a configuration in which the thickness t3 of at least one of the first connecting portion C1 and the second connecting portion C2 is relatively large.

[0094] (Aspect 3) In the method for manufacturing the heat exchanger 6 described in aspect 1 or aspect 2, at least one of the first beam b1 forming the first connecting portion C1 and the second beam b2 forming the second connecting portion C2 is scanned in a zigzag pattern in the longitudinal direction d0, thereby making the thickness t3 of at least one of the first connecting portion C1 and the second connecting portion C2 larger than the thickness t2 of the adjacent portion 92b.

[0095] According to this configuration, it is possible to realize a configuration in which the thickness t3 of at least one of the first connecting portion C1 and the second connecting portion C2 is relatively large.

[0096] (Aspect 4) In the method for manufacturing a heat exchanger 6 described in any one of aspects 1 to 3, at least one of the first beam b1 forming the first connecting portion C1 and the second beam b2 forming the second connecting portion C2 is repeatedly scanned alternately in a first direction d1 intersecting the longitudinal direction d0 and a second direction d2 opposite to the first direction d1 while changing its position in the longitudinal direction d0, thereby making the thickness t3 of at least one of the first connecting portion C1 and the second connecting portion C2 larger than the thickness t2 of the adjacent portion 92b.

[0097] According to this configuration, it is possible to realize a configuration in which the thickness t3 of at least one of the first connecting portion C1 and the second connecting portion C2 is relatively large.

[0098] (Aspect 5) In the method for manufacturing a heat exchanger 6 described in any one of aspects 1 to 4, at least one of the first beam b1 forming the first connecting portion C1 and the second beam b2 forming the second connecting portion C2 is repeatedly scanned alternately in a first direction d1 intersecting the longitudinal direction d0 and a second direction d2 intersecting both the longitudinal direction d0 and the first direction d1 while changing its position in the longitudinal direction d0, thereby making the thickness t3 of at least one of the first connecting portion C1 and the second connecting portion C2 larger than the thickness t2 of the adjacent portion 92b.

[0099] According to this configuration, it is possible to realize a configuration in which the thickness t3 of at least one of the first connecting portion C1 and the second connecting portion C2 is relatively large.

[0100] (Mode 6) In the method for manufacturing a heat exchanger 6 described in any one of modes 1 to 5, by repeatedly scanning in a direction intersecting the longitudinal direction d0 by at least one of the first beam b1 forming the first connecting portion C1 and the second beam b2 forming the second connecting portion C2 while changing position in the longitudinal direction d0, the thickness t3 of at least one of the first connecting portion C1 and the second connecting portion C2 is made larger than the thickness t2 of the adjacent portion 92b.

[0101] According to this configuration, it is possible to realize a configuration in which the thickness t3 of at least one of the first connecting portion C1 and the second connecting portion C2 is relatively large.

[0102] (Aspect 7) In the method for manufacturing a heat exchanger 6 described in any one of aspects 1 to 6, by scanning in the longitudinal direction d0 by at least one of the first beam b1 forming the first connecting portion C1 and the second beam b2 forming the second connecting portion C2 multiple times while changing the position in the thickness direction of the plate (second plate 92), the thickness t3 of at least one of the first connecting portion C1 and the second connecting portion C2 is made larger than the thickness t2 of the adjacent portion 92b.

[0103] According to this configuration, it is possible to realize a configuration in which the thickness t3 of at least one of the first connecting portion C1 and the second connecting portion C2 is relatively large.

[0104] (Aspect 8) A manufacturing method of a heat exchanger 206 is a manufacturing method of a heat exchanger 206 in which a heat exchanger having a plurality of plates 9, each of which is a fin 7 or a partition wall 8, is manufactured by additive manufacturing, the manufacturing method including forming one plate (first plate 91) of the plurality of plates 9 by either a first beam b1 irradiated into a first irradiation area A1 or a second beam b2 irradiated into a second irradiation area A2 that partially overlaps with the first irradiation area A1, and forming another plate (second plate 292) of the plurality of plates 9 by both the first beam b1 and the second beam b2, wherein in one layer (nth layer), a thickness t4 of the another plate (second plate 292) is greater than a thickness t5 of the one plate (first plate 91).

[0105] According to this configuration, the thickness t4 of the second plate 292 formed by both the first beam b1 and the second beam b2 can be made larger than the thickness t5 of the first plate 91. Therefore, even if a misalignment occurs between the irradiation position of the first beam b1 and the irradiation position of the second beam b2 in the overlapping area A3 where the first irradiation area A1 and the second irradiation area A2 overlap, the occurrence of defective molding of the overlapping portion 292a formed in the overlapping area A3 is suppressed. As a result, the occurrence of defective molding of the manufactured heat exchanger 206 can also be suppressed.

[0106] (Aspect 9) The heat exchanger 6 is a heat exchanger 6, 206 that is an additively formed body stacked in the stacking direction X, and includes a plate (second plate 92) that is a fin 7 or a partition wall 8, the plate (second plate 92) includes a first portion P1 and a second portion P2 that is thicker than the first portion P1, each of the first portion P1 and the second portion P2 has a molten pool mark row 93R that includes a plurality of molten pool marks 93 lined up in the stacking direction X, and the number of rows of the molten pool mark row 93R in the thickness direction in the second portion P2 is greater than the number of rows of the molten pool mark row 93R in the thickness direction in the first portion P1.

[0107] According to this configuration, the second portion P2 is formed by scanning multiple beams. Because the second portion P2 has a relatively large thickness, even if misalignment occurs between the irradiation positions of the beams, the objects formed by the beams can be connected to each other. This reduces the occurrence of defective molding of the second portion, thereby realizing a heat exchanger 6 with reduced defective molding.

[0108] (Mode 10) The heat exchanger 6 is equipped with fins 7, which include a first portion P1 and a second portion P2 that is thicker than the first portion P1, and each of the first portion P1 and the second portion P2 has a molten pool mark row 93R including a plurality of molten pool marks 93 lined up in the stacking direction X, the first portion P1 having one row of the molten pool mark row 93R in the thickness direction, and the second portion P2 having multiple rows of the molten pool mark row 93R in the thickness direction.

[0109] According to this configuration, the thickness of the first portion P1 of the fin 7 can be minimized while suppressing the occurrence of molding defects in the second portion P2.

[0110] (Aspect 11) The heat exchanger 6 is a layered shaped body stacked in the stacking direction X, and includes a plate (second plate 92) that is a fin 7 or a partition 8, the plate (second plate 92) includes a first portion P1 and a second portion P2 that is thicker than the first portion P1, and the crystal grain size of the second portion P2 in a cross section parallel to both the thickness direction of the plate (second plate 92) and the stacking direction X is larger than the crystal grain size of the first portion P1 in a cross section parallel to both the thickness direction of the plate (second plate 92) and the stacking direction X.

[0111] According to this configuration, the second portion P2 is formed by scanning multiple beams. Because the second portion P2 has a relatively large thickness, even if misalignment occurs between the irradiation positions of each beam, the objects formed by each beam can be connected to each other. This reduces molding defects in the second portion, thereby realizing a heat exchanger 6 with reduced molding defects. Furthermore, because the crystal grain size of the second portion P2 is larger than the crystal grain size of the first portion P1, the thermal conductivity of the second portion P2 can be made higher than that of the first portion P1.

[0112] (Aspect 12) The heat exchanger 6 is a layered shaped body stacked in the stacking direction X, and includes a plate (second plate 92) that is a fin 7 or a partition 8, the plate (second plate 92) includes a first portion P1 and a second portion P2 that is thicker than the first portion P1, and the crystal grain size of the second portion P2 in a cross section parallel to both the thickness direction of the plate (second plate 92) and the stacking direction X is smaller than the crystal grain size of the first portion P1 in a cross section parallel to both the thickness direction of the plate (second plate 92) and the stacking direction X.

[0113] According to this configuration, the second portion P2 is formed by scanning multiple beams. Because the second portion P2 has a relatively large thickness, even if misalignment occurs between the irradiation positions of each beam, the objects formed by each beam can be connected to each other. This reduces molding defects in the second portion, thereby realizing a heat exchanger 6 with reduced molding defects. Furthermore, because the crystal grain size of the second portion P2 is smaller than the crystal grain size of the first portion P1, the strength of the second portion P2 can be increased compared to the strength of the first portion P1.

[0114] 100 Additive manufacturing device 6, 206 Heat exchanger 7 Fin 8 Partition wall 9 Plate 91 First plate 92, 292 Second plate 93 Weld pool mark 93R Weld pool mark row 92a, 292a Overlapping portion 92b Adjacent portion A1 First irradiation area A2 Second irradiation area A3 Overlapping area b1 First beam b2 Second beam C1 First connecting portion C2 Second connecting portion d0 Longitudinal direction d1 First direction d2 Second direction P1 First portion P2 Second portion t1, t2, t3, t4, t5 Thickness X Stacking direction

Claims

1. A method for manufacturing a heat exchanger by additive manufacturing, which includes partially forming the plate by irradiating a first beam into a first irradiation area, and partially forming the plate by irradiating a second beam into a second irradiation area that partially overlaps with the first irradiation area, wherein in one layer, the cross section of the plate has a linear shape with a longitudinal direction, one end of the longitudinal direction of the portion of the plate formed by the first beam includes a first connecting portion located in the area where the first irradiation area and the second irradiation area overlap, and one end of the longitudinal direction of the portion of the plate formed by the second beam includes a second connecting portion located in the overlapping area and connected to the first connecting portion, and the thickness of at least one of the first connecting portion and the second connecting portion is greater than the thickness of an adjacent portion of the plate that is formed by either the first beam or the second beam and that is adjacent to the overlapping area.

2. A method for manufacturing a heat exchanger as described in claim 1, wherein the beam output of at least one of the first beam forming the first connecting portion and the second beam forming the second connecting portion is made greater than the beam output of the first beam or the second beam forming the adjacent portion, thereby making the thickness of at least one of the first connecting portion and the second connecting portion greater than the thickness of the adjacent portion.

3. A method for manufacturing a heat exchanger as described in claim 1, wherein at least one of the first beam forming the first connecting portion and the second beam forming the second connecting portion is scanned in a zigzag pattern in the longitudinal direction, thereby making the thickness of at least one of the first connecting portion and the second connecting portion greater than the thickness of the adjacent portion.

4. A method for manufacturing a heat exchanger as described in claim 1, wherein at least one of the first beam forming the first connecting portion and the second beam forming the second connecting portion is repeatedly scanned while changing its position in the longitudinal direction alternately in a first direction intersecting the longitudinal direction and a second direction opposite to the first direction, thereby making the thickness of at least one of the first connecting portion and the second connecting portion greater than the thickness of the adjacent portion.

5. A method for manufacturing a heat exchanger as described in claim 1, wherein at least one of the first beam forming the first connecting portion and the second beam forming the second connecting portion is repeatedly scanned while changing its position in the longitudinal direction alternately in a first direction intersecting the longitudinal direction and a second direction intersecting both the longitudinal direction and the first direction, thereby making the thickness of at least one of the first connecting portion and the second connecting portion greater than the thickness of the adjacent portion.

6. A method for manufacturing a heat exchanger as described in claim 1, wherein the thickness of at least one of the first connecting portion and the second connecting portion is made larger than the thickness of the adjacent portion by repeatedly scanning at least one of the first beam forming the first connecting portion and the second beam forming the second connecting portion in a direction intersecting the longitudinal direction while changing its position in the longitudinal direction.

7. A method for manufacturing a heat exchanger as described in claim 1, wherein the thickness of at least one of the first connecting portion and the second connecting portion is made larger than the thickness of the adjacent portion by scanning the longitudinal direction with at least one of the first beam forming the first connecting portion and the second beam forming the second connecting portion multiple times while changing the position in the thickness direction of the plate.

8. A method for manufacturing a heat exchanger by additive manufacturing, which comprises forming one of the plurality of plates by either a first beam irradiated into a first irradiation area or a second beam irradiated into a second irradiation area that partially overlaps with the first irradiation area, and forming another of the plurality of plates by both the first beam and the second beam, wherein in one layer, the thickness of the other plate is greater than the thickness of the one plate.

9. A heat exchanger that is an additively manufactured body stacked in a stacking direction, comprising a plate that is a fin or a partition wall, the plate including a first portion and a second portion that is thicker than the first portion, the first portion and the second portion each having a row of weld pool marks including a plurality of weld pool marks aligned in the stacking direction, and the number of rows of weld pool marks in the thickness direction in the second portion is greater than the number of rows of weld pool marks in the thickness direction in the first portion.

10. A heat exchanger that is an additively manufactured body stacked in a stacking direction, comprising fins, the fins including a first portion and a second portion thicker than the first portion, the first portion and the second portion each having a row of weld pool marks including a plurality of weld pool marks lined up in the stacking direction, the first portion having one row of the weld pool marks in the thickness direction, and the second portion having a plurality of rows of the weld pool marks in the thickness direction.

11. A heat exchanger that is an additively formed body stacked in a stacking direction, comprising a plate that is a fin or a partition wall, the plate including a first portion and a second portion that is thicker than the first portion, and the crystal grain size of the second portion in a cross section parallel to both the thickness direction of the plate and the stacking direction is larger than the crystal grain size of the first portion in a cross section parallel to both the thickness direction of the plate and the stacking direction.

12. A heat exchanger that is an additively formed body stacked in a stacking direction, comprising a plate that is a fin or a partition wall, the plate including a first portion and a second portion that is thicker than the first portion, and the crystal grain size of the second portion in a cross section parallel to both the thickness direction of the plate and the stacking direction is smaller than the crystal grain size of the first portion in a cross section parallel to both the thickness direction of the plate and the stacking direction.

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