Method of manufacturing three-dimensional modeling objects

Abstract

To provide a technology that can suppress the deformation of molding material located above the cavity of a three-dimensional molding object due to gravity.SOLUTION: The method of producing a three-dimensional modeling object comprises a first step of stacking a plurality of layers by ejecting a modeling material toward the stage to produce a modeling object having a cavity, the first step comprising a second step of stacking the layers such that each of the layers has an overlapping portion that contacts a layer immediately below it in the stacking direction and a non-overlapping portion that does not overlap with the layer immediately below and forms a space in the stacking direction. The non-overlapping portions form a top surface having two intersecting inclined surfaces above the cavity, and the angles of rise of each of the two inclined surfaces from a plane parallel to the stage are greater than 35° and less than 90°.SELECTED DRAWING: Figure 6

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses a three-dimensional shaping apparatus that forms a bridge structure without a support material.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When shaping a three-dimensional object having a cavity without using a support material, the portion located above the cavity may be deformed by gravity.

Means for Solving the Problems

[0005] According to a first aspect of the present disclosure, a method for manufacturing a three-dimensional object is provided. This manufacturing method includes a first step of forming a plurality of layers by discharging a shaping material toward a stage to form a shaped object having a cavity. The first step includes a second step of stacking the plurality of layers such that each of the layers has an overlapping portion that contacts the layer directly below in the stacking direction and a non-overlapping portion that does not overlap the layer directly below and forms a space downward. The non-overlapping portion forms a top surface having two intersecting inclined surfaces above the cavity. The rising angle of each of the two inclined surfaces from the surface parallel to the stage is 35° or more and less than 90°.

Brief Description of the Drawings

[0006]

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Mode for Carrying Out the Invention

[0007] A. First Embodiment: FIG. 1 is an explanatory diagram showing a schematic configuration of a three-dimensional shaping system 10 in the first embodiment. In FIG. 1, arrows indicating the X, Y, and Z directions orthogonal to each other are shown. The X direction and the Y direction are directions parallel to the horizontal plane, and the Z direction is a direction along the vertically upward direction. The arrows indicating the X, Y, and Z directions are also appropriately shown in other figures so that the illustrated directions correspond to those in FIG. 1. In the following description, when specifying the direction, the direction indicated by the arrow in each figure is defined as “+” and the opposite direction as “−”, and positive and negative signs are used together in the direction notation. Hereinafter, the +Z direction is also referred to as “up” and the −Z direction as “down”.

[0008] The three-dimensional shaping system 10 includes a three-dimensional shaping apparatus 100 and an information processing apparatus 400. The three-dimensional shaping apparatus 100 in the present embodiment is an apparatus for shaping a shaped object by a material extrusion method. The three-dimensional shaping apparatus 100 includes a control unit 300 for controlling each part of the three-dimensional shaping apparatus 100. The control unit 300 and the information processing apparatus 400 are connected to be communicable with each other.

[0009] The three-dimensional shaping apparatus 100 includes a head unit 110 that generates and discharges a shaping material, a shaping stage 210 that serves as a base of the shaped object, and a moving mechanism 230 that controls the discharge position of the shaping material.

[0010] The head unit 110 discharges the shaping material obtained by plasticizing the solid-state material onto the stage 210 under the control of the control unit 300. The head unit 110 includes a material supply unit 20 that is a supply source of the raw material before being converted into the shaping material, a plasticizing unit 30 that converts the raw material into the shaping material, and a discharge unit 60 that discharges the shaping material.

[0011] The material supply unit 20 supplies the raw material MR to the plasticizing unit 30. The material supply unit 20 is constituted by, for example, a hopper that stores the raw material MR. The material supply unit 20 is connected to the plasticizing unit 30 via the communication path 22. The raw material MR is input into the material supply unit 20 in the form of powder or pellets. As the raw material MR, for example, thermoplastic resin materials such as ABS (acrylonitrile-butadiene-styrene), PEEK (polyetheretherketone), and PP (polypropylene), or materials containing metal particles or ceramics and a binder are used.

[0012] 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 guides it to the discharge unit 60. In this embodiment, "plasticization" is a concept including melting, and is to change from a solid state to a state having fluidity. Specifically, in the case of a material in which glass transition occurs, plasticization means raising the temperature of the material above the glass transition point. In the case of a material in which glass transition does not occur, plasticization means raising the temperature of the material above the melting point.

[0013] The plasticizing unit 30 includes a screw case 31, a drive motor 32, a screw 40, and a barrel 50. The screw 40 is also called a flat screw, a rotor, or a scroll. The barrel 50 is also called a screw facing portion.

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

[0015] FIG. 2 is a perspective view showing a schematic configuration on the lower surface 48 side of the screw 40. The screw 40 shown in FIG. 2 is shown in a state where the positional relationship between the upper surface 47 and the lower surface 48 shown in FIG. 1 is reversed in the vertical direction for ease of understanding of the technology. The screw 40 has a substantially cylindrical shape in which the length in the axial direction, which is the direction along its central axis, is smaller than the length in the direction perpendicular to the axial direction. The screw 40 is arranged such that its rotation axis RX, which is the center of rotation, is parallel to the Z direction.

[0016] On the lower surface 48 of the screw 40, which is a surface intersecting the rotation axis RX, a spiral groove portion 42 is formed. The communication passage 22 of the material supply portion 20 described above communicates with the groove portion 42 from the side surface of the screw 40. In the present embodiment, the groove portion 42 is formed in three portions separated by ridge portions 43. Note that the number of the groove portions 42 is not limited to three, and may be one, or two or more. The groove portion 42 is not limited to a spiral shape, and may be a helical shape or an involute curve shape, or may be a shape extending in an arc from the central portion 46 toward the outer periphery.

[0017] As shown in FIG. 1, the lower surface 48 of the screw 40 faces the upper surface 52 of the barrel 50, and a space is formed between the groove portion 42 of the lower surface 48 of the screw 40 and the upper surface 52 of the barrel 50. The raw material MR is supplied from the material supply portion 20 to this space between the screw 40 and the barrel 50 through the material inlet 44 shown in FIG. 2.

[0018] In the barrel 50, a first barrel heater 57 and a second barrel heater 58 are embedded as heaters for heating the raw material MR supplied into the groove portion 42 of the rotating screw 40. The first barrel heater 57 heats the inner portion of the barrel 50. The second barrel heater 58 heats the outer portion of the barrel 50. The temperature of the first barrel heater 57 and the temperature of the second barrel heater 58 are controlled by the control unit 300. A communication hole 56 is provided at the center of the barrel 50.

[0019] FIG. 3 is a schematic plan view showing the upper surface 52 side of the barrel 50. A plurality of guide grooves 54 are formed on the upper surface 52 of the barrel 50, which are connected to the communication hole 56 and extend spirally from the communication hole 56 toward the outer periphery. Note that one end of the guide groove 54 may not be connected to the communication hole 56. Also, the guide groove 54 can be omitted.

[0020] The raw material MR supplied into the groove portion 42 of the screw 40 is plasticized in the groove portion 42 and flows along the groove portion 42 by the rotation of the screw 40, and is guided as a modeling material to the central portion 46 of the screw 40. The paste-like modeling material that has flowed into the central portion 46 and exhibits fluidity is supplied to the discharge portion 60 through the communication hole 56 provided at the center of the barrel 50. Note that in the modeling material, not all types of substances constituting the modeling material need to be plasticized. The modeling material only needs to be converted into a state having fluidity as a whole by plasticizing at least some types of substances among the substances constituting the modeling material.

[0021] The discharge portion 60 in FIG. 1 includes a nozzle 61 that discharges the modeling material, a flow path 65 of the modeling material provided between the screw 40 and the nozzle opening 62, and a discharge control unit 77 that controls the discharge of the modeling material.

[0022] The nozzle 61 is connected to the communication hole 56 of the barrel 50 through the flow path 65. The nozzle 61 discharges the modeling material generated in the plasticizing unit 30 from the nozzle opening 62 at the tip toward the stage 210. A nozzle heater 59 for suppressing a temperature drop of the modeling material is embedded in the nozzle 61. The temperature of the nozzle heater 59 is controlled by the control unit 300.

[0023] The discharge control unit 77 includes a discharge amount adjustment mechanism 70 that opens and closes the flow path 65, and a suction mechanism 75 that sucks and temporarily stores the modeling material.

[0024] The discharge amount adjustment mechanism 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 the present embodiment, the discharge amount adjustment mechanism 70 is constituted by a valve. The discharge amount adjustment mechanism 70 is driven by a first drive unit 74 under the control of the control unit 300. The first drive unit 74 is constituted 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, that is, 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 amount adjustment mechanism 70 can adjust the discharge amount of the modeling material and can control the on / off of the outflow of the modeling material.

[0025] The suction mechanism 75 includes a branch flow path 66 connected to the flow path 65 and a plunger 67 disposed in the branch flow path 66. The branch flow path 66 is connected to the flow path 65 between the discharge amount adjustment mechanism 70 and the nozzle opening 62. Hereinafter, moving the plunger 67 away from the flow path 65 within the branch flow path 66 is referred to as "pulling the plunger 67", and moving it closer to the flow path 65 is referred to as "pushing the plunger 67". The plunger 67 of the suction mechanism 75 is driven by a second drive unit 76 under the control of the control unit 300. The second drive unit 76 is constituted by, for example, a stepping motor or a rack and pinion mechanism that converts the rotational force of the stepping motor into the translational movement of the plunger 67.

[0026] The control unit 300 controls the suction mechanism 75 to temporarily suck the modeling material in the flow path 65 into the branch flow path 66 by pulling the plunger 67 when the discharge of the modeling material from the nozzle 61 stops. By doing so, it is possible to suppress the trailing phenomenon in which the modeling material hangs down from the nozzle opening 62 like a thread. Further, when the discharge of the modeling material from the nozzle 61 resumes, the control unit 300 adjusts the discharge amount of the modeling material sent out from the nozzle 61 to be constant by pulling the plunger 67 to suck the modeling material in the flow path 65 or pushing the plunger 67 to send the modeling material into the flow path 65. By doing so, it is possible to keep the line width of the modeling material constant when the discharge resumes.

[0027] 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 arranged to be parallel in the X and Y directions, that is, the horizontal direction. The stage 210 is provided with a stage heater 212 for suppressing the rapid cooling of the modeling material discharged onto the stage 210. The stage heater 212 is controlled by the control unit 300.

[0028] 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 the present embodiment, the position of the nozzle 61 is fixed, and the movement mechanism 230 moves the stage 210. The movement mechanism 230 is constituted by a three-axis positioner that moves the stage 210 in three-axis directions of the X, Y, and Z directions by the driving force of three motors. In this specification, unless otherwise specified, the movement of the nozzle 61 means moving the nozzle 61 or the discharge unit 60 relative to the stage 210.

[0029] In other embodiments, instead of the configuration in which the stage 210 is moved by the moving mechanism 230, a configuration may be adopted in which the moving mechanism 230 moves the nozzle 61 relative to the stage 210 while the position of the stage 210 is fixed. Further, a configuration may be adopted 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 may be adopted 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. Even with these configurations, the relative positional relationship between the nozzle 61 and the stage 210 can be changed.

[0030] The control unit 300 is a control device that controls the operation of the entire three-dimensional shaping apparatus 100. The control unit 300 is composed of a computer including one or a plurality of processors 310, a storage device 320 including a main storage device and an auxiliary storage device, and an input / output interface for inputting and outputting signals to and from the outside. The processor 310 controls the plasticizing unit 30 and the moving mechanism 230 according to the shaping data acquired from the information processing device 400 by executing the program stored in the storage device 320, and performs shaping of a shaped object on the stage 210. Note that the control unit 300 may be realized by a configuration combining circuits instead of being composed of a computer.

[0031] FIG. 4 is an explanatory diagram schematically showing a state in which the three-dimensional shaping apparatus 100 shapes a shaped object. In the three-dimensional shaping apparatus 100, as described above, the raw material MR in a solid state is plasticized to generate the shaping material MM. The control unit 300 discharges the shaping material MM from the nozzle 61 while changing the position of the nozzle 61 relative to the stage 210 in the direction along the shaping surface 211 of the stage 210 while maintaining the distance between the shaping surface 211 of the stage 210 and the nozzle 61. The shaping material MM discharged from the nozzle 61 is continuously deposited in the moving direction of the nozzle 61.

[0032] The control unit 300 repeatedly moves the nozzle 61 to form the layer ML. After forming one layer ML, the control unit 300 relatively moves the position of the nozzle 61 with respect to the stage 210 by a preset lamination pitch in the Z direction, which is the lamination direction. Then, the shaped object is shaped by laminating another layer ML on top of the layers ML formed so far.

[0033] The control unit 300 may, for example, move the nozzle 61 in the Z direction when one layer of the layer ML is completed, or may temporarily interrupt the discharge of the shaping material from the nozzle 61 when there are a plurality of shaping regions independent of each layer. In this case, the control unit 300 closes the flow path 65 by, for example, the discharge amount adjustment mechanism 70 to stop the discharge of the shaping material MM from the nozzle opening 62, and temporarily sucks the shaping material in the nozzle 61 by the suction mechanism 75. Further, the control unit 300, for example, after changing the position of the nozzle 61, opens the flow path 65 by the discharge amount adjustment mechanism 70 while discharging the shaping material in the suction mechanism 75, thereby restarting the deposition of the shaping material MM from the changed position of the nozzle 61.

[0034] FIG. 5 is an explanatory diagram showing a schematic configuration of the information processing apparatus 400. The information processing apparatus 400 is configured as a computer in which a CPU 410, a memory 420, a storage device 430, a communication interface 440, and an input / output interface 450 are interconnected by a bus 460. An input device 470 such as a keyboard and a mouse and a display unit 480 such as a liquid crystal display are connected to the input / output interface 450. The information processing apparatus 400 is connected to the control unit 300 of the three-dimensional shaping apparatus 100 via the communication interface 440.

[0035] The CPU 410 functions as a data generation unit 411 by executing a program stored in the storage device 430.

[0036] The data generation unit 411 generates modeling data. The modeling data is data representing information such as the movement path of the nozzle 61 with respect to the stage 210, the amount of the modeling material discharged from the nozzle 61, the rotational speed of the screw 40, and the like. The data generation unit 411 reads shape data representing the shape of a three-dimensional modeled object created using three-dimensional CAD software or three-dimensional CG software, and divides the shape of the three-dimensional modeled object into layers of a predetermined thickness. The data generation unit 411 generates modeling data by determining the movement path of the nozzle 61 and the amount of the modeling material so as to fill each of the divided layers with the modeling material. As the nozzle 61 moves along the movement path specified by the modeling data and the amount of the modeling material specified by the modeling data is discharged, a path having a predetermined line width is formed on the stage 210.

[0037] FIG. 6 is a flowchart of a shaping process for realizing a method for manufacturing a three-dimensional modeled object. This shaping process is executed by the control unit 300 of the three-dimensional shaping apparatus 100. In step S10, the control unit 300 acquires the modeling data generated by the information processing apparatus 400.

[0038] FIG. 7 is a schematic diagram showing the shape of the modeled object MD modeled in this embodiment. In this embodiment, a rectangular parallelepiped-shaped modeled object MD having a tubular cavity CV along the Y direction at the center in the X and Z directions is modeled. The cavity CV is used as a pipe, for example, after the completion of the modeled object MD, and fluid flows inside. The cavity CV has different shapes at the upper and lower parts. At the upper part of the cavity CV, a top surface TS having two intersecting inclined surfaces S1 and S2 is formed. The rising angle D of each of the two inclined surfaces S1 and S2 is less than 90°. The rising angle D is the angle at which the inclined surfaces S1 and S2 rise from a plane parallel to the stage 210. The rising angle D of the inclined surface S1 and the rising angle D of the inclined surface S2 may be the same angle or different angles. At the lower part of the cavity CV, a semi-circular bottom surface BS is formed. If the bottom surface BS at the lower part of the cavity CV is semi-circular, the flow path resistance of the cavity CV can be reduced when flowing fluid into the cavity CV after the completion of the modeled object MD. Such an effect is remarkable when the fluid is a liquid flowing as the fluid in the lower part of the cavity CV. The modeling data acquired from the information processing apparatus 400 is data for modeling the modeled object MD shown in FIG. 7 layer by layer.

[0039] In step S20 of FIG. 6, the control unit 300 executes a lamination process. In this lamination process, the control unit 300 controls the plasticizing unit 30, the discharge control unit 77, and the moving mechanism 230 according to the modeling data acquired in step S10, and discharges the modeling material toward the stage 210, thereby laminating a plurality of layers and modeling the modeled object MD having the cavity CV. Step S20 is also referred to as the first step.

[0040] The lamination process in step S20 includes the top surface forming process in step S30. The top surface forming process is a process for forming the top surface TS shown in FIG. 7. Step S30 is also referred to as the second step.

[0041] FIG. 8 is an explanatory diagram of the top surface forming process. FIG. 8 shows an enlarged view of a plurality of layers that form the uppermost part of the top surface TS. In the top surface forming process, the control unit 300 controls the plasticizing unit 30, the discharge control unit 77, and the moving mechanism 230 according to the modeling data, so that each layer has an overlapping portion OV1 that contacts the layer directly below in the stacking direction and a non-overlapping portion OV2 that does not overlap the layer directly below and forms a space downward. In FIG. 8, cross-hatching is applied to the overlapping portion OV1, and single hatching is applied to the non-overlapping portion OV2. By forming the non-overlapping portion OV2 in each layer, the control unit 300 forms a top surface TS having two intersecting inclined surfaces S1 and S2 above the cavity CV.

[0042] FIG. 9 is a diagram showing a cross-section of the molded object MD. Each of the layers for forming the cavity CV has an outermost peripheral region CR and an inner region IR that contacts the inside of the outermost peripheral region CR. The outermost peripheral region CR is a region for molding the outermost one turn of the molded object MD in each layer. In the example shown in FIG. 9, an example is shown in which the inner region IR is composed of a zigzag pattern with an infill rate of 100% and a honeycomb pattern with an infill rate of 25%. The zigzag pattern is formed in a region of the inner region IR close to the cavity CV, and the honeycomb pattern is formed in a region of the inner region IR far from the cavity CV. Note that the entire inner region IR may be molded by a single pattern with an infill rate of 100%. The pattern for molding the inner region IR is not limited to the zigzag pattern or the honeycomb pattern, and other patterns such as a concentric circle pattern or a triangle pattern may be used.

[0043] In step S30 described above, the control unit 300 molds each layer so that at least a part of the outermost peripheral path for molding the outermost peripheral region CR and the inner path for molding the inner region IR overlap. By doing so, it is possible to suppress the peeling of the outermost peripheral region CR from the inner region IR.

[0044] The amount by which the inner path overlaps with respect to the line width of the outermost path is referred to as the overlap amount. In FIG. 9, the range where overlap occurs is shown as the overlap portion OP. In step S30, the control unit 300 laminates each layer so that the outermost path and the inner path overlap at least in part of the non-overlapping portion OV2 that forms the top surface TS. That is, in FIG. 8, each layer is shaped so that the overlap portion OP is located in the single-hatching portion indicating the non-overlapping portion OV2, and the top surface TS is formed. By doing so, the strength of the top surface TS can be increased.

[0045] FIG. 10 is a diagram showing the shaping results of a plurality of samples having cavity portions CV. FIGS. 11 to 23 are images showing the shaping results of each sample. In the present embodiment, samples of 13 types of shaped objects MD with different rising angles D of the inclined surfaces S1 and S2, shaping materials, overlap amounts, etc. were shaped, and the external shapes of their cavity portions CV were visually confirmed and evaluated. In FIG. 10, the evaluation results are shown as "A" or "B". Evaluation A indicates that the cavity portion CV was well shaped, and evaluation B indicates that the cavity portion CV was not well shaped. Hereinafter, the details of each sample will be described.

[0046] As the shaping material for Sample 1, a metal material containing SUS630 metal particles and, as a binder, 7 parts by mass of a fluidity component, an adhesiveness component, a formability component, and a plasticizer was used. As the shaping conditions for Sample 1, the diameter of the nozzle opening 62 was 0.4 mm, the line width of the path was 0.5 mm, the lamination pitch was 0.2 mm, the material extrusion speed from the nozzle 61 was 50 mm / second, the temperature of the first barrel heater 57 was 90°C, the temperature of the second barrel heater 58 was 80°C, the temperature of the nozzle heater 59 was 125°C, and the overlap amount was 30%. The shape of Sample 1 was the same as the shape of the shaped object MD shown in FIG. 7. Specifically, a shaped object MD was shaped in which a substantially circular cavity portion CV with a diameter of 10 mm was provided at the center of a 25 mm square cube, and the rising angles D of the inclined surfaces S1 and S2 constituting the top surface TS of the cavity portion CV were each 35°. As a result, as shown in FIG. 11, a cavity portion CV with a good shape was formed without shaping a support structure inside the cavity portion CV.

[0047] The shaping material and shaping conditions of Sample 2 are the same as those of Sample 1. The shape of Sample 2 was made different from that of Sample 1 only in the rising angles D of the inclined surfaces S1 and S2, which were set to 45°. As a result, as shown in Fig. 12, a cavity CV with a good shape was formed without shaping a support structure inside the cavity CV.

[0048] The shaping material and shaping conditions of Sample 3 are the same as those of Sample 1. The shape of Sample 3 was made different from that of Sample 1 only in the rising angles D of the inclined surfaces S1 and S2, which were set to 55°. As a result, as shown in Fig. 13, a cavity CV with a good shape was formed without shaping a support structure inside the cavity CV.

[0049] The shaping material and shaping conditions of Sample 4 are the same as those of Sample 1. The shape of Sample 4 was made different from that of Sample 1 only in the rising angles D of the inclined surfaces S1 and S2, which were set to 70°. As a result, as shown in Fig. 14, a cavity CV with a good shape was formed without shaping a support structure inside the cavity CV.

[0050] The shaping material and shaping conditions of Sample 5 are the same as those of Sample 1. The shape of Sample 5 was made 1.5 times the size of Sample 1. Specifically, a shaped object MD was shaped with a substantially circular cavity CV with a diameter of 15 mm provided in a 37.5 mm square cube, and the rising angles D of the inclined surfaces S1 and S2 constituting the top surface TS of the cavity CV were set to 35° respectively. As a result, as shown in Fig. 15, a cavity CV with a good shape was formed without shaping a support structure inside the cavity CV.

[0051] The shaping material and shaping conditions of Sample 6 are the same as those of Sample 1. The shape of Sample 1 has the same dimensions of 25 mm in the X and Y directions as Sample 1, and a different dimension of 30 mm in the Z direction from Sample 1. The shape of the cavity CV is the same as that of Sample 1. In Sample 6, the height of the cavity CV from the stage 210 was not changed from Sample 1, and the shaped object MD was shaped so that a thickness of 5 mm was added to the upper part of the cavity CV. As a result, as shown in Fig. 16, a cavity CV with a good shape was formed without shaping a support structure inside the cavity CV.

[0052] The shaping material of Sample 7 is different from that of Sample 1 and is a PLA resin that does not contain metal powder. The shaping conditions were set such that the temperature of the first barrel heater 57 was 240°C, the temperature of the second barrel heater 58 was 230°C, and the temperature of the nozzle heater 59 was 205°C, and the other conditions were the same as those of Sample 1. The shape of Sample 7 is the same as that of Sample 1. As a result, as shown in Fig. 17, a cavity CV with a good shape was formed without shaping a support structure inside the cavity CV.

[0053] The shaping material of Sample 8 is the same as that of Sample 1. In Sample 8, the overlap amount was set to 10%, and the other shaping conditions were the same as those of Sample 1. The shape of Sample 8 is the same as that of Sample 1. As a result, as shown in Fig. 18, a cavity CV with a good shape was formed without shaping a support structure inside the cavity CV.

[0054] The shaping material of Sample 9 is the same as that of Sample 1. In Sample 9, the overlap amount was set to 50%, and the other shaping conditions were the same as those of Sample 1. The shape of Sample 9 is the same as that of Sample 1. As a result, as shown in Fig. 19, a cavity CV with a good shape was formed without shaping a support structure inside the cavity CV.

[0055] The shaping material of Sample 10 is the same as that of Sample 1. In Sample 10, the overlap amount was set to 100%, and other shaping conditions were the same as those of Sample 1. The shape of Sample 10 is the same as that of Sample 1. As a result, as shown in Fig. 20, a cavity CV with a good shape was formed without shaping a support structure inside the cavity CV.

[0056] The shaping material and shaping conditions of Sample 11 are the same as those of Sample 1. In Sample 11, the shape of the cavity CV was a circle with a diameter of 15 mm, and two inclined surfaces S1 and S2 were not formed. As a result, as shown in Fig. 21, the material dripped from the top surface TS of the cavity CV, and the cavity CV could not be formed well.

[0057] The shaping material and shaping conditions of Sample 12 are the same as those of Sample 1. In Sample 12, only the rising angle D of the inclined surfaces S1 and S2 was made different from that of Sample 1 and set to 30°. As a result, as shown in Fig. 22, the material dripped from the upper surface of the cavity CV, and the cavity CV could not be formed well.

[0058] The shaping material and shaping conditions of Sample 13 are the same as those of Sample 1. In Sample 13, only the overlap amount was made different from that of Sample 1 and set to 0%. As a result, as shown in Fig. 23, the material dripped from the top surface TS of the cavity CV, and the cavity CV could not be formed well.

[0059] As described above, in Sample 11 where the rising angle D of the inclined surfaces S1 and S2 forming the top surface TS of the cavity CV is 30°, the cavity CV was not formed well, while in Sample 1 where the rising angle D is 35°, the cavity CV was formed well. Therefore, in order to suppress the deformation of the portion located above the cavity CV of the shaped object MD due to gravity and form the cavity CV without forming a support structure, the rising angle D is preferably 35° or more. Also, in order to form the top surface TS by the two inclined surfaces S1 and S2, the rising angle D needs to be less than 90°. Therefore, the rising angle D of the inclined surfaces S1 and S2 is preferably 35° or more and less than 90°. Also, in Samples 2 to 4 where the rising angles D are 45°, 55°, and 70° respectively, the cavity CV could be formed well. Therefore, in order to suppress the stress concentration at the intersection of the inclined surfaces S1 and S2, the rising angle D is preferably 35° or more and 70° or less, and more preferably 35° or more and 55° or less.

[0060] In Sample 5, the dimensions of the shaped object MD are 1.5 times those of Sample 1, and in Sample 6, the thickness of the shaped object above the cavity CV is increased by 5 mm. Also, in Sample 7, a resin material lighter in weight than metal is used. For these Samples 5, 6, and 7 as well, the cavity CV could be formed well by setting the rising angle D of the inclined surfaces S1 and S2 to 35°. Therefore, regardless of the size and weight of the shaped object MD and the thickness of the shaped object above the cavity CV, the rising angle D is preferably 35° or more. In particular, when a metal material is used as the shaping material, since the weight applied to the top surface TS becomes large, the effect of defining the rising angle D of the inclined surfaces S1 and S2 as described above is significant.

[0061] In Sample 8 with an overlap amount of 10%, the cavity CV was formed well. In Sample 13 with an overlap amount of 0%, the cavity CV could not be formed well. Therefore, when forming the shaped object MD, it is preferable to form each layer so that at least a part of the outermost peripheral path for forming the outermost peripheral region CR and the inner path for forming the inner region IR overlap. In particular, from the results of Sample 8, the overlap amount by which the inner path overlaps the outermost peripheral path is preferably 10% or more with respect to the line width of the outermost peripheral path. Note that in Samples 8, 1, 9, and 10 where the overlap amounts are 10%, 30%, 50%, and 100% respectively, the cavity CVs are all formed well. However, when the overlap amount is 100%, depending on the shaping conditions, bulges may occur due to the paths overlapping in the overlap portion, and the shaping accuracy may decrease. Therefore, the upper limit of the overlap amount is preferably 50%. That is, the overlap amount is preferably 10% or more and 50% or less.

[0062] B. Other Embodiments: (B1) FIG. 24 is a diagram showing another shape of the cavity CV. In the above embodiment, the cavity CV is formed at the center of the shaped object MD. In contrast, the cavity CV may be formed so as to have an opening downward at the bottom of the shaped object MD as shown in FIG. 24.

[0063] (B2) FIG. 25 is a diagram showing a cross-section of another shaped object MD. The cavity CV described in the above embodiment extends linearly within the shaped object MD. In contrast, within the shaped object MD, as shown in FIG. 25, a plurality of cavities CV may be formed so as to intersect or connect with each other. In this case, it is preferable that the shaped object MD is shaped so that chamfers such as R-chamfers are applied to the corner portions CP of the portions where the plurality of cavities CV intersect or the corner portions CP of the portions where the plurality of cavities CV are connected, as shown by the dashed line in FIG. 25. By applying a chamfer to the corner portion CP, the flow path resistance of the cavity CV can be reduced when flowing a fluid through the cavity CV.

[0064] (B3) In the above-described embodiment, each of the layers for forming the cavity CV has an outermost peripheral region CR and an inner region IR that is in contact with the inside of the outermost peripheral region CR. In contrast, each of the layers for forming the cavity CV may not have the outermost peripheral region CR. That is, each layer may be composed only of the inner region IR. In this case, since the outermost peripheral region CR does not exist, an overlap portion OP where the outermost peripheral path for shaping the outermost peripheral region CR and the inner path for shaping the inner region IR overlap is not formed. Therefore, in the non-overlapping portion OV2 for forming the top surface TS, the outermost peripheral path and the inner path do not overlap either.

[0065] (B4) In the above-described embodiment, the inner region IR that is in contact with the inside of the outermost peripheral region CR may have an intermediate region for one or more circumferences that surrounds the entire inner region IR so as to be in contact with the outermost peripheral region CR. An overlap portion OP is formed by the outermost peripheral region CR and the intermediate region overlapping. In this case, the outermost peripheral region CR and the intermediate region in contact with the inside thereof can be called an outer shell region, and the inner region IR existing inside the outer contour region can be called an infill region.

[0066] (B5) In the above-described embodiment, the plasticizing unit 30 plasticizes the material by means of a flat screw. In contrast, the plasticizing unit 30 may, for example, plasticize the material by rotating an in-line screw. Also, the plasticizing unit 30 may plasticize the filamentous material with a heater.

[0067] (B6) In the above-described embodiment, the three-dimensional shaping device 100 can shape a three-dimensional shaped object using, for example, various materials such as a material having thermoplasticity, a metal material, or a ceramic material as a main material. The "main material" means the material that forms the center of the shape of the three-dimensional shaped object and means the material that occupies a content rate of 50 mass% or more in the three-dimensional shaped object. The above-described shaping materials include those in which these main materials are melted alone and those in which some components contained together with the main material are melted into a paste form.

[0068] When using a material with thermoplasticity as the main material, in the plasticizing section 30, when the material is plasticized, a shaping material is generated.

[0069] As the material with thermoplasticity, for example, the following thermoplastic resin materials can be used. <Examples of Thermoplastic Resin Materials> General-purpose engineering plastics such as polypropylene resin (PP), polyethylene resin (PE), polyacetal resin (POM), polyvinyl chloride resin (PVC), polyamide resin (PA), acrylonitrile-butadiene-styrene resin (ABS), polylactic acid resin (PLA), polyphenylene sulfide resin (PPS), polyetheretherketone (PEEK), polycarbonate (PC), modified polyphenylene ether, polybutylene terephthalate, polyethylene terephthalate, etc.; engineering plastics such as polysulfone, polyethersulfone, polyphenylene sulfide, polyarylate, polyimide, polyamideimide, polyetherimide, polyetheretherketone, etc.

[0070] The material with thermoplasticity may be mixed with pigments, metals, ceramics, and other additives such as wax, flame retardant, antioxidant, heat stabilizer, etc. The material with thermoplasticity is plasticized in the plasticizing section 30 by the rotation of the screw 40 and the heating of the heater and converted into a molten state. The shaping material generated by the melting of the material with thermoplasticity is ejected from the nozzle 61 and then cured by the temperature drop.

[0071] It is desirable that the material with thermoplasticity is heated above its glass transition temperature and injected from the nozzle 61 in a completely molten state. For example, the glass transition temperature of ABS resin is about 120°C, and it is desirable to be about 200°C when injected from the nozzle 61.

[0072] In the three-dimensional shaping apparatus 100, instead of the above-described material having thermoplasticity, for example, the following metal materials may be used as the main material. In this case, it is desirable that a component that melts during the generation of the shaping material is mixed with the powder material obtained by pulverizing the following metal material, and the mixture is introduced into the plasticizing unit 30 as a raw material. <Examples of metal materials> Single metals such as magnesium (Mg), iron (Fe), cobalt (Co), chromium (Cr), aluminum (Al), titanium (Ti), copper (Cu), nickel (Ni), or alloys containing one or more of these metals. <Examples of the alloy> Maraging steel, stainless steel, cobalt-chromium-molybdenum, titanium alloy, nickel alloy, aluminum alloy, cobalt alloy, cobalt-chromium alloy.

[0073] In the three-dimensional shaping apparatus 100, instead of the above-described metal materials, a ceramic material can be used as the main material. As the ceramic material, for example, oxide ceramics such as silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, or non-oxide ceramics such as aluminum nitride can be used. When using a metal material or a ceramic material as described above as the main material, the shaping material disposed on the stage 210 may be cured by sintering with laser irradiation or hot air.

[0074] The powder materials of the metal materials and ceramic materials introduced into the material supply unit 20 as raw materials may be a mixed material in which powders of a single metal, alloy powders, or ceramic material powders are mixed in a plurality of types. Further, the powder materials of the metal materials and ceramic materials may be coated with, for example, the thermoplastic resin exemplified above or other thermoplastic resins. In this case, in the plasticizing unit 30, it may be assumed that the thermoplastic resin melts and fluidity is exhibited.

[0075] For the powder materials of metallic materials and ceramic materials input into the material supply unit 20 as raw materials, for example, the following solvents can also be added. The solvents can be used by selecting one or a combination of two or more selected from the following. <Examples of solvents> Water; (Poly)alkylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, and propylene glycol monoethyl ether; Acetic acid esters such as ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, and isobutyl acetate; Aromatic hydrocarbons such as benzene, toluene, and xylene; Ketones such as methyl ethyl ketone, acetone, methyl isobutyl ketone, ethyl-n-butyl ketone, diisopropyl ketone, and acetylacetone; Alcohols such as ethanol, propanol, and butanol; Tetraalkylammonium acetates; Sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide; Pyridine solvents such as pyridine, γ-picoline, and 2,6-lutidine; Tetraalkylammonium acetate (for example, tetrabutylammonium acetate, etc.); Ionic liquids such as butyl carbitol acetate.

[0076] In addition, for the powder materials of metallic materials and ceramic materials input into the material supply unit 20 as raw materials, for example, the following binders can also be added. <Examples of binders> Various resins such as polyethylene, polypropylene, polyolefin, acrylic resin, styrene resin, polyvinyl chloride, polyamide, polyester, polyether, polyvinyl alcohol, and polyvinyl pyrrolidone, various waxes, paraffin, higher fatty acids, higher alcohols, higher fatty acid esters, etc.

[0077] C. Other forms: The present disclosure is not limited to the above-described embodiments, and can be implemented in various configurations without departing from the gist thereof. For example, the technical features of the embodiments corresponding to the technical features in each of the forms described below can be appropriately replaced or combined in order to solve some or all of the above-described problems, or to achieve some or all of the above-described effects. Further, if the technical feature is not described as essential in this specification, it can be appropriately deleted.

[0078] (1) According to the first aspect of the present disclosure, a method for manufacturing a three-dimensional object is provided. This manufacturing method includes a first step of forming a shaped object having a cavity by laminating a plurality of layers by discharging a shaping material toward a stage. The first step includes a second step of laminating the plurality of layers such that each of the layers has an overlapping portion that contacts the layer directly below in the lamination direction and a non-overlapping portion that does not overlap the layer directly below and forms a space downward. By the non-overlapping portion, a top surface having two intersecting inclined surfaces is formed above the cavity, and the rising angle of each of the two inclined surfaces from the surface parallel to the stage is 35° or more and less than 90°. According to such a form, it is possible to suppress deformation of the portion located above the cavity of the three-dimensional object due to gravity.

[0079] (2) In the above aspect, the rising angle may be 35° or more and 70° or less.

[0080] (3) In the above aspect, the rising angle may be 35° or more and 55° or less.

[0081] (4) In the above aspect, in the first step, the shaped object having the tubular cavity and having a semi-circular portion facing the top surface in the lamination direction may be formed. According to such a form, when flowing a fluid through the cavity, the flow path resistance of the cavity can be reduced.

[0082] (5) In the above-described embodiment, each of the layers has an outermost peripheral region and an inner region that is in contact with the inside of the outermost peripheral region. In the second step, each of the layers may be shaped such that at least a part of an outermost peripheral path for shaping the outermost peripheral region and an inner path for shaping the inner region overlap. According to such an embodiment, it is possible to suppress the separation between the outermost peripheral region and the inner region.

[0083] (6) In the above-described embodiment, the overlap amount by which the inner path overlaps the outermost peripheral path may be 10% or more and 50% or less with respect to the line width of the outermost peripheral path. According to such an embodiment, it is possible to effectively suppress the separation between the outermost peripheral path and the inner path.

[0084] (7) In the above-described embodiment, in the second step, each of the layers may be laminated such that the outermost peripheral path and the inner path overlap at least a part of the non-overlapping portion. According to such an embodiment, it is possible to suppress the separation between the outermost peripheral path and the inner path in the non-overlapping region.

[0085] (8) In the above-described embodiment, the shaping material may contain metal particles and a thermoplastic resin.

[0086] The present disclosure can be realized in various forms, not limited to the method for manufacturing the three-dimensional shaped object described above, such as a three-dimensional shaping apparatus, a computer program, and a non-transitory tangible recording medium in which the computer program is recorded in a computer-readable manner.

Explanation of Reference Numerals

[0087] 10…Three-dimensional shaping system, 20…Material supply unit, 22…Communication path, 30…Plasticizing unit, 31…Screw case, 32…Drive motor, 40…Screw, 42…Groove portion, 43…Rib portion, 44…Material inlet, 46…Central portion, 47…Upper surface, 48…Lower surface, 50…Barrel, 52…Upper surface, 54…Guide groove, 56…Communication hole, 57…First barrel heater, 58…Second barrel heater, 59…Nozzle heater, 60…Discharge unit, 61…Nozzle, 62…Nozzle opening, 65…Flow path, 66…Branch flow path, 67…Plunger, 70…Discharge amount adjustment mechanism, 74…First drive unit, 75…Suction mechanism, 76…Second drive unit, 77…Discharge control unit, 100…Three-dimensional shaping device, 110…Head unit, 210…Stage, 211…Shaping surface, 212…Stage heater, 230…Moving mechanism, 300…Control unit, 310…Processor, 320…Storage device, 400…Information processing device, 410…CPU, 411…Data generation unit, 420…Memory, 430…Storage device, 440…Communication interface, 450…Input / output interface, 460…Bus, 470…Input device, 480…Display unit

Claims

1. It has a first step of forming a shaped object having a cavity by laminating a plurality of layers by discharging a shaping material toward a stage, In the first step, the first step has a second step of laminating the plurality of layers such that each of the layers has an overlapping portion that contacts the layer directly below in the lamination direction and a non-overlapping portion that does not overlap the layer directly below and forms a space downward, A top surface having two intersecting inclined surfaces is formed above the cavity by the non-overlapping portion, The rising angle of each of the two inclined surfaces from the surface parallel to the stage is 35° or more and less than 90°, A method for manufacturing a three-dimensional shaped object.

2. A method for manufacturing a three-dimensional shaped object according to claim 1, The rising angle is 35° or more and 70° or less, a method for manufacturing a three-dimensional shaped object.

3. A method for manufacturing a three-dimensional shaped object according to claim 1, The rising angle is 35° or more and 55° or less, a method for manufacturing a three-dimensional shaped object.

4. A method for manufacturing a three-dimensional shaped object according to claim 1, In the first step, the shaped object having the tubular cavity and having a semi-circular portion facing the top surface in the lamination direction is formed, a method for manufacturing a three-dimensional shaped object.

5. A method for manufacturing a three-dimensional shaped object according to claim 1, Each of the layers has an outermost peripheral region and an inner region in contact with the inside of the outermost peripheral region, In the second step, each of the layers is formed such that at least a part of an outermost peripheral path for forming the outermost peripheral region and an inner path for forming the inner region overlap, a method for manufacturing a three-dimensional shaped object.

6. A method for manufacturing a three-dimensional shaped object according to claim 5, In the method for manufacturing a three-dimensional object, the overlap amount by which the inner path overlaps the outermost peripheral path is 10% or more and 50% or less with respect to the line width of the outermost peripheral path.

7. A method for manufacturing a three-dimensional object according to claim 5, In the second step, each layer is laminated so that the outermost peripheral path and the inner path overlap at least a part of the non-overlapping portion. A method for manufacturing a three-dimensional object.

8. A method for manufacturing a three-dimensional object according to claim 1, The modeling material includes metal particles and a thermoplastic resin. A method for manufacturing a three-dimensional object.

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