Method for manufacturing three-dimensional molded object

Abstract

To provide a technology capable of suppressing warping in a three-dimensional molded object.SOLUTION: A method for manufacturing a three-dimensional molded object includes: a first step of molding an object having a first overhang part by ejecting a first molding material and laminating molding layers; and a second step of molding a brim structure by ejecting a second molding material and laminating brim layers. The brim structure includes: a first brim layer adjacent to at least a portion of the molding layer located at a bottom layer of the object; and a second brim layer laminated on top of the first brim layer and adjacent to at least a portion of the first overhang part. The brim structure is a structure that is separated from the object molded at the first step.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing a three-dimensional object. [Background technology]

[0002] Patent Document 1 discloses that, in order to prevent warping during the formation of a three-dimensional object, a circular brim is formed so as to contact the outer periphery of the layer to be formed so as to be in contact with the area where warping is predicted to occur. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-72943 Summary of the Invention [Problem to be solved by the invention]

[0004] Even when a circular brim is formed, depending on the shape of the three-dimensional object, it may not be possible to prevent warping of the three-dimensional object. [Means for solving the problem]

[0005] According to a first aspect of the present disclosure, there is provided a method for manufacturing a three-dimensional object, the method comprising: a first step of forming an object having a first overhang portion by discharging a first modeling material and stacking modeling layers; and a second step of forming a brim structure by discharging a second modeling material and stacking brim layers, the brim structure including a first brim layer adjacent to and in contact with at least a portion of the modeling layer that is the lowest layer of the object, and a second brim layer stacked on the first brim layer and adjacent to at least a portion of the first overhang portion, the brim structure being a structure that is separated from the object formed in the first step. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is an explanatory diagram illustrating a schematic configuration of a three-dimensional modeling apparatus. [Figure 2] FIG. 2 is a perspective view showing a schematic configuration of a flat screw. [Figure 3] FIG. 2 is a schematic plan view of the barrel. [Figure 4] 1A to 1C are explanatory diagrams schematically illustrating the basic operation of the three-dimensional modeling apparatus. [Figure 5] 10 is a flowchart of a three-dimensional modeling process. [Figure 6] FIG. 2 is an explanatory diagram schematically illustrating a cross-sectional side view of the object and the brim structure. [Figure 7] 4 is an explanatory diagram showing the shapes of the first brim layer and the second brim layer as viewed from above. FIG. [Figure 8] FIG. 10 is an explanatory diagram schematically illustrating a cross-sectional side view of a shaped object and a brim structure according to a second embodiment. [Figure 9] FIG. 10 is an explanatory diagram schematically illustrating a cross-sectional side view of a shaped object and a brim structure according to a third embodiment. [Figure 10] FIG. 11 is an explanatory diagram showing the shapes of the first brim layer and the second brim layer in a top view according to a third embodiment. [Figure 11] FIG. 10 is an explanatory diagram schematically illustrating a cross-sectional side view of a shaped object and a brim structure according to a fourth embodiment. [Figure 12] FIG. 13 is an explanatory diagram schematically illustrating a cross-sectional side view of a shaped object and a brim structure according to a fifth embodiment. [Figure 13] FIG. 2 is a top view of a modeling layer, a brim layer, and a brim support layer. [Figure 14] FIG. 13 is an explanatory diagram schematically illustrating a cross-sectional side view of a shaped object and a brim structure according to a sixth embodiment. [Figure 15] FIG. 13 is a diagram showing a modified example of the sixth embodiment. [Figure 16] FIG. 13 is an explanatory diagram schematically illustrating a cross-sectional side view of a shaped object and a brim structure according to a seventh embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] A. First embodiment: FIG. 1 is an explanatory diagram showing a schematic configuration of a three-dimensional printing apparatus 100 according to a first embodiment. FIG. 1 shows arrows indicating mutually orthogonal X, Y, and Z directions. The X and Y directions are parallel to a horizontal plane, and the Z direction is a vertically upward direction. The arrows indicating the X, Y, and Z directions are also shown in other figures as appropriate so that the illustrated directions correspond to those in FIG. 1. In the following description, when specifying the direction, positive and negative signs are used in combination to indicate the direction indicated by the arrow in each figure, with "+" indicating the direction indicated by the arrow and "-" indicating the opposite direction. Hereinafter, the +Z direction will also be referred to as "up" and the -Z direction as "down."

[0008] The three-dimensional modeling apparatus 100 of this embodiment is an apparatus that forms a three-dimensional object by a material extrusion method. The three-dimensional modeling apparatus 100 includes a modeling unit 110 that generates and dispenses a modeling material, a modeling stage 210 that serves as a base for the three-dimensional object, a movement mechanism 230 that controls the dispense position of the modeling material, and a control unit 300 that controls each part of the three-dimensional modeling apparatus 100. While FIG. 1 shows one modeling unit 110, in this embodiment, the three-dimensional modeling apparatus 100 is provided with multiple modeling units 110 that generate and dispense different modeling materials. Each modeling unit 110 has the same configuration.

[0009] Under the control of the control unit 300, the modeling unit 110 ejects a modeling material, which is a plasticized solid material, onto the stage 210. The modeling unit 110 includes a material supply unit 20, which is a supply source of raw materials before they are converted into the modeling material, a plasticization unit 30, which converts the raw materials into the modeling material, and a discharge unit 60, which discharges the modeling material.

[0010] The material supply unit 20 supplies the raw material MR to the plasticizing unit 30. The material supply unit 20 is configured, for example, by a hopper that stores the raw material MR. The material supply unit 20 is connected to the plasticizing unit 30 via a communication passage 22. The raw material MR is fed into the material supply unit 20 in the form of pellets, powder, or the like. As the raw material MR, for example, a resin material such as ABS (acrylonitrile butadiene styrene), PEEK (polyether ether ketone), or PP (polypropylene) is used. The raw material MR may also contain inorganic materials such as metals and ceramics.

[0011] The plasticizing unit 30 plasticizes the raw material MR supplied from the material supply unit 20 to generate a paste-like modeling material that exhibits fluidity, and then guides the material to the discharge unit 60. In this embodiment, "plasticization" is a concept that includes melting, and refers to changing a material from a solid to a fluid state. Specifically, for materials that undergo glass transition, plasticization refers to raising the temperature of the material above the glass transition point. For materials that do not undergo glass transition, plasticization refers to raising the temperature of the material above the melting point.

[0012] The plasticizing section 30 includes a screw case 31, a drive motor 32, a flat screw 40, and a barrel 50. The flat screw 40 is also called a rotor or a scroll. The barrel 50 is also called a screw facing portion.

[0013] FIG. 2 is a perspective view showing a schematic configuration of the lower surface 48 side of the flat screw 40. To facilitate understanding of the technology, the flat screw 40 shown in FIG. 2 is shown with the positional relationship between the upper surface 47 and the lower surface 48 shown in FIG. 2 reversed in the vertical direction. FIG. 3 is a schematic plan view showing the upper surface 52 side of the barrel 50. The flat screw 40 has a roughly cylindrical shape in which the length in the axial direction, which is the direction along its central axis, is shorter than the length in the direction perpendicular to the axial direction. The flat screw 40 is positioned so that the rotation axis RX, which is its rotation center, is parallel to the Z direction.

[0014] As shown in Fig. 1, the flat screw 40 is housed in a screw case 31. An upper surface 47 of the flat screw 40 is connected to a drive motor 32, and the flat screw 40 rotates in the screw case 31 by the rotational driving force generated by the drive motor 32. The drive motor 32 is driven under the control of the control unit 300. The flat screw 40 may be driven by the drive motor 32 via a reducer.

[0015] As shown in Fig. 2, a spiral groove 42 is formed on the lower surface 48 of the flat screw 40, which is the surface that intersects with the rotation axis RX. The communication passage 22 of the material supply unit 20 described above communicates with the groove 42 from the side surface of the flat screw 40. In this embodiment, three grooves 42 are formed, separated by ridges 43. The number of grooves 42 is not limited to three, and may be one, or two or more. The groove 42 is not limited to a spiral shape, but may also be a spiral or involute curve shape, or may have a shape that extends in an arc from the center to the outer periphery.

[0016] The lower surface 48 of the flat screw 40 faces the upper surface 52 of the barrel 50, and a space is formed between the groove 42 of the lower surface 48 of the flat screw 40 and the upper surface 52 of the barrel 50. Raw material MR is supplied to this space between the flat screw 40 and the barrel 50 from the material supply section 20 through the material inlet 44 shown in FIG.

[0017] As shown in Fig. 1, a barrel heater 58 is embedded in the barrel 50 to heat the raw material MR supplied into the groove 42 of the rotating flat screw 40. A communication hole 56 is provided in the center of the barrel 50. As shown in Fig. 3, a plurality of guide grooves 54 are formed in the top surface 52 of the barrel 50, connected to the communication hole 56 and extending spirally from the communication hole 56 toward the outer periphery. Note that one end of the guide groove 54 does not have to be connected to the communication hole 56. Furthermore, the guide groove 54 may be omitted.

[0018] The raw material MR supplied into the groove 42 of the flat screw 40 is plasticized in the groove 42, flows along the groove 42 due to the rotation of the flat screw 40, and is guided to the central portion 46 of the flat screw 40 as a modeling material. The pasty modeling material that has flowed into the central portion 46 and exhibits fluidity is supplied to the discharge portion 60 through a communication hole 56 provided in the center of the barrel 50. Note that it is not necessary for all types of substances constituting the modeling material to be plasticized. It is sufficient for the modeling material to be converted into a fluid state as a whole by plasticizing at least some of the types of substances constituting the modeling material.

[0019] The discharge unit 60 in FIG. 1 includes a nozzle 61 that discharges the modeling material, a flow path 65 for the modeling material provided between the flat screw 40 and the nozzle opening 62, and a discharge control unit 77 that controls the discharge of the modeling material.

[0020] The nozzle 61 is connected to the communication hole 56 of the barrel 50 through a flow path 65. The nozzle 61 discharges the modeling material produced in the plasticizing section 30 from a nozzle opening 62 at the tip thereof toward the stage 210.

[0021] The discharge control unit 77 includes a discharge adjustment unit 70 that opens and closes the flow path 65, and a suction unit 75 that sucks in the modeling material and temporarily stores it.

[0022] The discharge adjustment unit 70 is provided in the flow path 65 and changes the opening degree of the flow path 65 by rotating within the flow path 65. In this embodiment, the discharge adjustment unit 70 is configured by a valve. The discharge adjustment unit 70 is driven by a first drive unit 74 under the control of the control unit 300. The first drive unit 74 is configured by, for example, a stepping motor. The control unit 300 can adjust the flow rate of the modeling material flowing from the plasticizing unit 30 to the nozzle 61, i.e., the discharge amount of the modeling material discharged from the nozzle 61, by controlling the rotation angle of the valve using the first drive unit 74. The discharge adjustment unit 70 can adjust the discharge amount of the modeling material and can also control the on / off of the outflow of the modeling material.

[0023] The suction unit 75 is connected between the discharge adjustment unit 70 and the nozzle opening 62 in the flow path 65. When the discharge of the modeling material from the nozzle 61 stops, the suction unit 75 temporarily sucks the modeling material in the flow path 65, thereby suppressing the tailing phenomenon in which the modeling material hangs like a string from the nozzle opening 62. In this embodiment, the suction unit 75 is configured with a plunger. The suction unit 75 is driven by a second drive unit 76 under the control of the control unit 300. The second drive unit 76 is configured with, for example, a stepping motor or a rack-and-pinion mechanism that converts the rotational force of the stepping motor into translational motion of the plunger.

[0024] The stage 210 is disposed at a position facing the nozzle opening 62 of the nozzle 61. In the first embodiment, the modeling surface 211 of the stage 210 facing the nozzle opening 62 of the nozzle 61 is disposed so as to be parallel to the X and Y directions, i.e., the horizontal direction. The stage 210 may be provided with a stage heater to prevent the modeling material discharged onto the stage 210 from cooling rapidly.

[0025] The movement mechanism 230 changes the relative position between the stage 210 and the nozzle 61 under the control of the control unit 300. In this embodiment, the position of the nozzle 61 is fixed, and the movement mechanism 230 moves the stage 210. The movement mechanism 230 is configured by a three-axis positioner that moves the stage 210 in three axial directions, that is, the X, Y, and Z directions, using the driving forces of three motors. In this specification, unless otherwise specified, movement of the nozzle 61 means moving the nozzle 61 and the discharge unit 60 relative to the stage 210.

[0026] In other embodiments, instead of a configuration in which the moving mechanism 230 moves the stage 210, a configuration in which the moving mechanism 230 moves the nozzle 61 relative to the stage 210 while the position of the stage 210 is fixed may be employed. Alternatively, a configuration in which the moving mechanism 230 moves the stage 210 in the Z direction and moves the nozzle 61 in the X and Y directions, or a configuration in which the moving mechanism 230 moves the stage 210 in the X and Y directions and moves the nozzle 61 in the Z direction may be employed. Even with these configurations, the relative positional relationship between the nozzle 61 and the stage 210 can be changed.

[0027] The control unit 300 is configured by a computer including one or more processors 310, a storage unit 320 including a main storage unit and an auxiliary storage unit, and an input / output interface for inputting and outputting signals to and from the outside. The processor 310 executes a program stored in the storage unit 320 to control the modeling unit 110 and the movement mechanism 230 in accordance with the modeling data stored in the storage unit 320, thereby modeling a three-dimensional object on the stage 210. The modeling data for modeling the three-dimensional object includes, for each layer obtained by slicing the shape of the three-dimensional object, path information indicating the movement path of the nozzle 61 and discharge amount information indicating the amount of modeling material dispensed along each movement path. The movement path of the nozzle 61 refers to the path along which the nozzle 61 moves relative to the modeling surface 211 of the stage 210 while discharging the modeling material. The modeling data is acquired, for example, from another computer connected to the control unit 300 via a communication line or from a recording medium, and stored in the storage unit 320. The control unit 300 may be realized by a combination of circuits instead of being configured by a computer.

[0028] 4 is an explanatory diagram schematically illustrating the basic operation of the three-dimensional modeling apparatus 100. As described above, in the three-dimensional modeling apparatus 100, the raw material MR in a solid state is plasticized to produce the modeling material MM. The control unit 300 discharges the modeling material MM from the nozzle 61 while changing the position of the nozzle 61 relative to the stage 210 in a direction along the modeling surface 211 of the stage 210, while maintaining the distance between the nozzle 61 and the modeling surface 211 of the stage 210. The modeling material MM discharged from the nozzle 61 is continuously deposited in the direction of movement of the nozzle 61.

[0029] The control unit 300 repeatedly moves the nozzle 61 to form the forming layers ML. After forming one forming layer ML, the control unit 300 moves the position of the nozzle 61 relative to the stage 210 in the +Z direction, which is the stacking direction of the forming layers ML. Then, a three-dimensional object is formed by stacking additional forming layers ML on the forming layers ML that have been formed so far. Hereinafter, the three-dimensional object will also be simply referred to as the formed object.

[0030] The control unit 300 may temporarily suspend the discharge of the modeling material from the nozzle 61, for example, when the nozzle 61 moves in the Z direction after completing the formation of one modeling layer ML, or when each modeling layer has multiple independent modeling regions. In this case, the discharge adjustment unit 70 closes the flow path 65 to stop the discharge of the modeling material MM from the nozzle opening 62, and the suction unit 75 temporarily sucks the modeling material from the nozzle 61. After changing the position of the nozzle 61, the control unit 300 opens the flow path 65 with the discharge adjustment unit 70 while discharging the modeling material from the suction unit 75, thereby restarting the deposition of the modeling material MM from the new position of the nozzle 61.

[0031] Fig. 5 is a flowchart of the three-dimensional printing process executed by the control unit 300. A method for manufacturing a three-dimensional object is realized by executing the three-dimensional printing process shown in Fig. 5. Fig. 6 is an explanatory diagram schematically showing a side cross section of the object MD1 and brim structure BS1 formed by the three-dimensional printing process.

[0032] In step S10 of FIG. 5, the control unit 300 controls the modeling unit 110 and the movement mechanism 230 to model a release layer PL on the modeling surface 211 of the stage 210. The release layer PL is also called a "raft." A modeling material for modeling the release layer PL is, for example, PP. The release layer PL is a layer that enables the modeled object MD1 and the brim structure BS1 to be easily peeled off from the stage 210. In FIG. 6, the release layer PL is formed by stacking three layers. The number of layers that make up the release layer PL is, for example, 1 to 10 and can be arbitrarily specified by the user. The release layer PL is used as a temporary stage. Data for modeling the release layer PL may be included in the modeling data or may be pre-stored in the storage unit 320.

[0033] In step S20 shown in FIG. 5, the control unit 300 controls the modeling unit 110, which dispenses the first modeling material, and the movement mechanism 230 to model the bottom layer of the model MD1 on the peel-off layer PL in accordance with the modeling data. The bottom layer of the model MD1 is the modeling layer ML that forms the bottom surface of the model MD1. The first modeling material is, for example, ABS. In this embodiment, the first modeling material is a material different from the modeling material used to model the peel-off layer PL. In other words, the peel-off layer PL and the model MD1 are modeled by discharging different modeling materials from different modeling units 110.

[0034] In step S30 shown in FIG. 5, the control unit 300 controls the modeling unit 110, which dispenses the second modeling material, and the movement mechanism 230 to model the bottom layer of the brim structure BS1 on the peeling layer PL. The brim structure BS1 is a structure that prevents the modeling object MD1 from peeling off from the peeling layer PL. The control unit 300 models the brim layer BL, which is the bottom layer of the brim structure BS1, so that it is adjacent to and in contact with the modeling layer ML, which is the bottom layer of the modeling object MD1. "Adjacent to and in contact with" means that the two layers are arranged next to each other and in contact with each other. In this embodiment, the second modeling material used to model the brim layer BL is the same material as the first modeling material used to model the model MD1. Therefore, the modeling unit 110 that dispenses the second modeling material is the same modeling unit 110 that dispenses the first modeling material. The data for forming the brim layer BL may be included in the forming data, or the control unit 300 may analyze the forming data for forming the object MD1 and generate the data so that the brim layer BL is formed around the object MD1. Note that the second forming material used for forming the brim layer BL and the first forming material used for forming the object MD1 may be different materials.

[0035] The order of the processes in Step S20 and Step S30 may be reversed. That is, the brim layer BL located at the bottom of the brim structure BS1 may be formed before the formation layer ML located at the bottom of the object MD1.

[0036] In step S40 of FIG. 5, the control unit 300 controls the molding unit 110 and the movement mechanism 230 to mold the remaining layers of the object MD1, i.e., the molding layers ML other than the bottommost layer of the object MD1, and the remaining layers of the brim structure BS1, i.e., the brim layers BL other than the bottommost layer of the brim structure BS1. In step S40, the object MD1 and the brim structure BS1 are molded on the release layer PL. The brim structure BS1 includes at least a first brim layer BL1 and a second brim layer BL2. The first brim layer BL1 is a brim layer BL adjacent to at least a portion of the molding layer ML that is the bottommost layer of the molding layers ML. The second brim layer BL2 is a brim layer BL that is stacked on top of the first brim layer BL1.

[0037] 7 is an explanatory diagram showing the shapes of the first brim layer BL1 and the second brim layer BL2 viewed from above. As shown in FIG. 7, in this embodiment, the brim layer BL is molded to a constant width along a path that goes around the periphery of the molding layer ML. In this embodiment, the first brim layer BL1 contacts the entire periphery of the lowermost molding layer ML. The second brim layer BL2 is layered on the first brim layer BL1 so as to overlap at least a portion of the first brim layer BL1.

[0038] Prior to starting the three-dimensional printing process, the control unit 300 may receive from the user, via an input interface provided in the control unit 300, specifications for the number of brim layers BL constituting the brim structure BS1 and the in-plane width of the brim layers BL. If the user does not specify the number of layers or the width, a predetermined number of layers and width are set. In this embodiment, a common width is set as the in-plane width of each brim layer BL constituting the brim structure BS1. The in-plane width of the brim layer BL is the dimension of the brim layer BL in the direction perpendicular to the horizontal direction from the side surface of the object MD1. The width of the brim layer BL is not limited to a dimensional value, and may also be specified by the number of revolutions of the nozzle 61 that revolves around the printing layer ML to print the brim layer BL.

[0039] In step S50 of FIG. 5, the peel layer PL and the brim structure BS1 are separated from the object MD1 formed in steps S20 and S40. The separation step in step S50 is performed manually or by using a cutting device. The object MD1 is manufactured through the series of steps described above. Note that the above-mentioned step S20 and the step of forming the forming layer ML in step S40 are collectively referred to as the "first step." The step S30 and the step of forming the brim layer BL in step S40 are collectively referred to as the "second step."

[0040] FIG. 6 shows an example in which a model MD1 and a brim structure BS1 are formed on a peel layer PL in the above-described three-dimensional modeling process. The model MD1 has a first overhang portion OH1 and a constricted portion CP. The first overhang portion OH1 is a portion that will be suspended in the air after the model MD1 is completed. The constricted portion CP is a portion of the model MD1 that is recessed in a direction intersecting the vertical direction. In other words, the constricted portion CP is a portion of the side surface of the model MD that is recessed toward the interior of the model MD1. In FIG. 6, the upper half of the constricted portion CP has an overhanging shape. However, in this embodiment, the overhanging shape included in the constricted portion CP does not correspond to the first overhang portion OH1. In the example shown in FIG. 6, the model MD1 is formed using seven modeling layers ML. The brim structure BS1 is formed using five brim layers BL.

[0041] In this embodiment, in step S40 described above, the control unit 300 stacks multiple fabrication layers ML of the same shape and area while shifting the fabrication positions of each layer in the horizontal direction to form the first overhang portion OH1 and the constricted portion CP. The control unit 300 forms each brim layer BL so that it is adjacent to and in contact with at least a portion of the first overhang portion OH1, but does not adjacently contact the constricted portion CP. In this manner, as shown in FIG. 6 , a brim structure BS1 is formed, which has a second overhang portion OH2 that supports the first overhang portion OH1 of the object MD1 from below, but does not contact the constricted portion CP. The brim layers BL of the brim structure BS1 that face the constricted portion CP in the horizontal direction are stacked vertically upward. In this way, in this embodiment, when stacking the brim layers BL from the second brim layer BL2 onwards, the control unit 300 allows the shape of each brim layer BL to change towards the outside of the object MD1, while prohibiting the shape of each brim layer BL from changing towards the inside of the object MD1.

[0042] According to the first embodiment described above, the object MD1, which has the first overhang portion OH1 and is made up of multiple formation layers ML, and the brim structure BS1, which is made up of multiple brim layers BL, are formed on the release layer PL so that at least the bottom layer is adjacent to and in contact with each other. This allows the object MD1 to adhere better to the release layer PL than when only the object MD1 is formed on the release layer PL or when only one brim layer BL is formed. As a result, the possibility of warping of the object MD1 can be reduced.

[0043] Furthermore, in this embodiment, although the object MD1 has a constricted portion CP, the brim layer BL does not contact the constricted portion CP. This prevents the brim structure BS1 from becoming trapped in the constricted portion CP when the brim structure BS1 is separated from the object MD1. This improves the separability of the object MD1 and the brim structure BS1.

[0044] In this embodiment, brim layers BL having a common width are stacked in each layer to form a brim structure BS1 having a second overhang portion OH2 that contacts at least a portion of the first overhang portion OH1 of the object MD1. This allows the first overhang portion OH1 of the object MD1 to be supported by the second overhang portion OH2 of the brim structure BS1. As a result, the molding accuracy of the object MD1 can be improved.

[0045] In this embodiment, the brim layer BL is formed by discharging the second modeling material along a path that circumvents the periphery of the modeling layer ML. Therefore, the brim layer BL is formed so as to contact the entire modeling layer ML, which improves the adhesion of the model MD1 to the release layer PL compared to when the brim layer BL is formed so as to contact only a portion of the modeling layer ML. As a result, warping of the model MD1 can be effectively prevented.

[0046] In the first embodiment, the control unit 300 forms the object MD1 that includes the constricted portion CP. However, the control unit 300 may form an object that does not include the constricted portion CP.

[0047] B. Second embodiment: 8 is an explanatory diagram schematically illustrating a side cross section of the object MD2 and brim structure BS2 formed in the second embodiment. The second embodiment differs from the first embodiment in the method for forming the brim structure BS2 in the three-dimensional printing process. The shape of the object MD2 is the same as that of the object MD1 in the first embodiment. The configuration of the three-dimensional printing device 100 in the second and subsequent embodiments is the same as that in the first embodiment.

[0048] In the second embodiment, in step S40 of the 3D printing process shown in Fig. 5 , if there is a portion of the printing range of the n+1th brim layer BL (n is a natural number) counting from the bottom layer that protrudes outward from the printing range of the nth brim layer BL counting from the bottom layer by more than the width set commonly for all brim layers BL, the control unit 300 does not print the protruding portion. In other words, if there is a non-overlapping area between the n+1th brim layer BL and the nth brim layer BL that does not overlap in the vertical direction by more than the aforementioned width, the control unit 300 does not print the non-overlapping area of ​​the n+1th brim layer BL. In Fig. 8 , the portion that is not printed in the second embodiment is indicated by a dashed rectangle.

[0049] According to the second embodiment described above, it is possible to prevent the formation of a portion of the brim structure BS2 that does not contribute to supporting the first overhang portion OH1, as shown by the dashed rectangle in Fig. 8. It is also possible to prevent the shape of the brim structure BS2 from collapsing due to the weight of the portion that protrudes outward.

[0050] C. Third embodiment: Fig. 9 is an explanatory diagram schematically showing a side cross section of the object MD3 and brim structure BS3 formed in the third embodiment. Fig. 10 is an explanatory diagram showing the shapes of the first brim layer BL1 and the second brim layer BL2 in the third embodiment as viewed from above. The third embodiment differs from the first embodiment in the method for forming the brim structure BS3 in the three-dimensional printing process. The shape of the object MD3 is the same as that of the object MD1 in the first embodiment.

[0051] In the third embodiment, in step S40 of the 3D printing process shown in Fig. 5, if there is a portion of the printing range of the second brim layer BL2 and the third or subsequent brim layers BL that extends outside the printing range of the first brim layer BL1, the control unit 300 does not print the protruding portion. In other words, if there is a non-overlapping area in the second brim layer BL2 and the third or subsequent brim layers BL that does not overlap with the first brim layer BL1 in the vertical direction, the control unit 300 does not print the non-overlapping area. In Fig. 9, the portion that is not printed in the third embodiment is indicated by a dashed rectangle.

[0052] According to the third embodiment described above, the brim layer BL with a printing range exceeding the printing range of the lowest brim layer BL is not stacked on the lowest brim layer BL. Therefore, the second overhang portion OH2 is not formed in the brim structure BS3. As a result, a brim structure BS3 with a stable shape can be formed.

[0053] D. Fourth embodiment: 11 is an explanatory diagram schematically illustrating a side cross section of a model MD4 and a brim structure BS4 formed in the fourth embodiment. The fourth embodiment differs from the first embodiment in the method for forming the brim structure in the three-dimensional printing process.

[0054] In the fourth embodiment, in step S40 of the three-dimensional printing process shown in Fig. 5, the control unit 300 forms the brim structure BS4 so that the in-plane width of the (n+1)th brim layer BL counting from the bottom is equal to or less than the in-plane width of the nth brim layer BL counting from the bottom. The initial width of the brim layer BL may be arbitrarily specified by the user. Furthermore, in the fourth embodiment, as in the first embodiment, the control unit 300 forms each brim layer BL so that it contacts the first overhang portion OH1 of the object MD4 adjacently, but does not contact the constricted portion CP of the object MD4 adjacently.

[0055] According to the fourth embodiment described above, the width of the brim layer BL constituting the brim structure BS4 decreases vertically upward, allowing the brim structure BS4 to be formed in a stable position relative to the peel-off layer PL. As a result, warping of the object MD1 can be effectively suppressed. Furthermore, in the fourth embodiment, the brim structure BS4 can be formed so that the second overhang portion OH2 is not formed, allowing the brim structure BS4 to be formed in a more stable position relative to the peel-off layer PL.

[0056] E. Fifth embodiment: 12 is an explanatory diagram schematically illustrating a side cross section of an object MD5 and a brim structure BS5 formed in the fifth embodiment. The fifth embodiment differs from the first embodiment in the method of forming the brim structure in the three-dimensional printing process. The shape of the object MD5 is the same as that of the object MD1 in the first embodiment.

[0057] In the fifth embodiment, in step S40 of the three-dimensional modeling process shown in Figure 5, the control unit 300 models a brim structure BS5 having the same shape as the brim structure BS1 in the first embodiment, and also models a second brim structure CS1 that supports the second overhang portion OH2 of the brim structure BS5 from below.

[0058] 13 is a top view of the lowermost modeling layer ML, the brim layer BL, and the brim support layer CSL that constitute the second brim structure CS1. Unlike the brim layer BL, the brim support layer BSL is not modeled along a path that goes around the periphery of the modeling layer ML, but along a path that is independent of the brim layer BL.

[0059] According to the fifth embodiment described above, by forming the second brim structure CS1 below the brim structure BS5, the second overhang portion OH2 of the brim structure BS5 can be supported from below. This prevents the brim structure BS5 and the object MD5 from losing their shape. The second brim structure CS1 may be formed using the same material as the brim structure BS5, or a different material.

[0060] F. Sixth embodiment: 14 is an explanatory diagram schematically illustrating a side cross section of an object MD6 and a brim structure BS6 formed in the sixth embodiment. The sixth embodiment differs from the first embodiment in the method of forming the brim structure in the three-dimensional printing process. The shape of the object MD6 is the same as the object MD1 in the first embodiment.

[0061] In the sixth embodiment, in step S40 of the three-dimensional printing process shown in FIG. 5 , the control unit 300 prints a brim structure BS6 having the same shape as the brim structure BS1 in the first embodiment, and also prints a third brim structure CS2 at the constricted portion CP of the object MD6. Printing this third brim structure CS2 prevents the shape of the upper portion of the constricted portion CP of the object MD6 from collapsing. The third brim structure CS2 may be printed using the same printing material as the brim structure BS6, or a different printing material. Printing the third brim structure CS2 using a water-soluble printing material makes it easy to remove the third brim structure CS2.

[0062] Fig. 15 is a diagram showing a modified example of the sixth embodiment. In the sixth embodiment, a large amount of molding material is consumed because the third brim structure CS2 is formed in addition to the brim structure BS6. For this reason, as shown in Fig. 15, the control unit 300 may form only an area of ​​a predetermined width adjacent to and in contact with the object MD6 within the combined printing range of the brim structure BS6 and the third brim structure CS2. This reduces the amount of molding material consumed.

[0063] G. Seventh embodiment: 16 is an explanatory diagram schematically illustrating a side cross section of an object MD7 and a brim structure BS7 formed in the seventh embodiment. The seventh embodiment differs from the first embodiment in the method of forming the brim structure in the three-dimensional printing process. The shape of the object MD7 is the same as the object MD1 in the first embodiment.

[0064] In the seventh embodiment, the control unit 300 forms a supporting structure SS below the first overhang portion OH1 of the object MD7 and at the constricted portion CP. The material used to form the supporting structure SS may be the same as or different from that used for the object MD7 and the brim structure BS7. In the seventh embodiment, the control unit 300 layers the brim layer BL along a path that circles the periphery of the combined printing range of the object MD7 and the supporting structure SS. As a result, the brim structure BS7 extends vertically upward, and the second overhang portion OH2 is not formed.

[0065] According to the seventh embodiment described above, the support structure SS is formed to support the first overhang portion OH1 and the constricted portion CP of the object MD7, which makes the object MD7 less likely to lose its shape. Furthermore, the brim structure BS7 is formed around the object MD7 and the support structure SS facing vertically upward, which allows the object MD7 and the support structure SS to be well adhered to the release layer PL.

[0066] H. Other Embodiments: (H1) In the above embodiment, the control unit 300 forms the object and the brim structure on the release layer PL. However, the control unit 300 may form the object and the brim structure on the stage 210.

[0067] (H2) In the above embodiment, the control unit 300 forms the brim layer BL by discharging the modeling material from the nozzle 61 so that the modeling material circulates around the modeling layer ML. In contrast, the control unit 300 may also form the modeling layer BL so that the nozzle 61 does not circulate around the modeling layer ML but rather contacts a portion of the modeling layer ML.

[0068] (H3) In the above embodiment, the molding unit 110 plasticizes the material using the flat screw 40. However, the molding unit 110 may also plasticize the material by, for example, rotating an in-line screw. Alternatively, the molding unit 110 may also plasticize the filament-shaped material using a heater.

[0069] I. Other forms: The present disclosure is not limited to the above-described embodiments and can be realized in various configurations without departing from the spirit thereof. For example, the technical features of the embodiments corresponding to the technical features in each aspect described below can be appropriately replaced or combined to solve some or all of the above-described problems or achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted.

[0070] (1) According to a first aspect of the present disclosure, there is provided a method for manufacturing a three-dimensional object, the method comprising: a first step of forming an object having a first overhang portion by discharging a first modeling material and stacking modeling layers; and a second step of forming a brim structure by discharging a second modeling material and stacking brim layers, the brim structure including a first brim layer adjacent to and in contact with at least a portion of the modeling layer that is the lowest layer of the object, and a second brim layer stacked on the first brim layer and adjacent to at least a portion of the first overhang portion, the brim structure being a structure that is separated from the object formed in the first step. According to this configuration, the object made up of multiple modeling layers and the brim structure made up of multiple brim layers are modeled so that they are adjacent to each other and in contact with each other at least in the lowest layer, thereby suppressing warping of the three-dimensional object.

[0071] (2) In the above embodiment, the object may have a constricted portion recessed in a direction intersecting the vertical direction, and in the second step, the brim layer may be laminated so as not to be adjacent to or in contact with the constricted portion. This embodiment can improve the separability of the object having the constricted portion and the brim structure.

[0072] (3) In the above aspect, the brim layers may have a common width in the in-plane direction among the brim layers constituting the brim structure, and the brim structure may be formed by stacking the brim layers of the common width in the second step, thereby forming the brim structure having a second overhang portion in contact with the first overhang portion. In this aspect, the first overhang portion of the formed object can be supported by the second overhang portion of the brim structure.

[0073] (4) In the above embodiment, in the second step, when n is a natural number, if there is a portion of the brim layer (n+1)-th layer counting from the bottom that protrudes beyond the width of the brim layer (n-th layer counting from the bottom), the protruding portion may not be shaped. This configuration can prevent the shape of the brim structure from being distorted.

[0074] (5) In the above embodiment, if a portion of the second brim layer in the molding range of the first brim layer extends outside the molding range of the second brim layer in the second step, the protruding portion may not be molded. In this embodiment, a brim structure with a stable shape can be molded.

[0075] (6) In the above embodiment, in the second step, the brim structure may be shaped so that the in-plane width of the (n+1)th brim layer counting from the bottom layer is equal to or less than the in-plane width of the nth brim layer counting from the bottom layer, where n is a natural number. This embodiment allows the brim structure to be stably shaped.

[0076] (7) In the above-described embodiment, the brim layer may be formed by discharging the second modeling material along a path that circumferentially surrounds the modeling layer in the second step. In this embodiment, warping of the modeled object can be more effectively suppressed.

[0077] The present disclosure is not limited to the above-described method for manufacturing a three-dimensional object, but can be realized in various forms, such as a three-dimensional printing system, a three-dimensional printing device, a computer program, and a non-transitory tangible recording medium on which a computer program is recorded in a computer-readable manner. [Explanation of symbols]

[0078] 20...material supply unit, 22...communicating passage, 30...plasticizing unit, 31...screw case, 32...drive motor, 40...flat screw, 42...groove portion, 43...ridge portion, 44...material inlet, 46...center portion, 47...upper surface, 48...lower surface, 50...barrel, 52...upper surface, 54...guide groove, 56...communicating hole, 58...barrel heater, 60...discharge unit, 61...nozzle, 62...nozzle opening, 65...flow path, 70...discharge adjustment unit, 74...first drive unit, 75...suction unit, 76...second drive unit, 77...discharge control unit, 100...three-dimensional modeling device, 110...modeling unit, 210...stage, 211...modeling surface, 230...movement mechanism, 300...control unit, 310...processor, 320...memory unit

Claims

1. a first step of discharging a first modeling material to stack modeling layers to form a modeled object having a first overhang portion; a second step of discharging a second modeling material to laminate a brim layer to form a brim structure; The brim structure includes a first brim layer adjacent to and in contact with at least a portion of the modeling layer located at the bottom of the model, and a second brim layer stacked on the first brim layer and adjacent to and in contact with at least a portion of the first overhang portion, The brim structure is a structure that is separated from the object formed in the first step. A method for manufacturing three-dimensional objects.

2. The method for manufacturing a three-dimensional object according to claim 1, the object has a constricted portion that is recessed in a direction intersecting the vertical direction, In the second step, the brim layer is laminated so as not to be in contact with the constricted portion.

3. The method for manufacturing a three-dimensional object according to claim 1, a width of the brim layer in an in-plane direction is a common width among the brim layers constituting the brim structure, In the second step, the brim layer having the width is stacked to form the brim structure having a second overhang portion in contact with the first overhang portion.

4. The method for manufacturing a three-dimensional object according to claim 3, In the second step, when n is a natural number, if there is a portion of the brim layer that protrudes beyond the width of the brim layer that is the nth layer counting from the bottom layer within the modeling range of the brim layer that is the n+1th layer counting from the bottom layer, the protruding portion is not modeled.

5. The method for manufacturing a three-dimensional object according to claim 1, In the second step, if there is a portion of the molding range of the second brim layer that protrudes outside the molding range of the first brim layer, the protruding portion is not molded.

6. The method for manufacturing a three-dimensional object according to claim 1, In the second step, the brim structure is shaped so that the in-plane width of the (n+1)th brim layer counting from the bottom layer is equal to or less than the in-plane width of the nth brim layer counting from the bottom layer, where n is a natural number.

7. The method for manufacturing a three-dimensional object according to claim 1, In the second step, the brim layer is formed by ejecting the second modeling material along a path that circumferentially surrounds the modeling layer.

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