Three-dimensional modeling device

Abstract

To rapidly stabilize the discharge amount of a plasticized material in a three-dimensional modeling device.SOLUTION: A three-dimensional modeling device comprises: a plasticizing unit for plasticizing a material to create a plasticized material; a nozzle having a nozzle opening to discharge the plasticized material; and a control unit for controlling the plasticizing unit. The control unit executes at least one operation selected from a first operation in which, when it adjusts the discharge amount of the plasticized material out of the nozzle from a first discharge amount to a second discharge amount larger than the first discharge amount, it adjusts revolution speed of a screw from a first speed to a second speed larger than the first speed, and thereafter adjusts to a third speed larger than the first speed and smaller than the second speed, or a second operation in which, when it adjusts discharge amount of the plasticized material out of the nozzle from a third discharge amount to a fourth discharge amount smaller than the third discharge amount, it adjusts revolution speed of the screw from a fourth speed to a fifth speed smaller than the fourth speed, and thereafter adjusts to a sixth speed larger than the fifth speed and smaller than the fourth speed.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present disclosure relates to a three-dimensional shaping apparatus.

Background Art

[0002] Patent Document 1 discloses a three-dimensional shaping apparatus including a flow rate adjustment mechanism capable of controlling the amount of molten material discharged from a nozzle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the three-dimensional shaping apparatus disclosed in Patent Document 1, the discharge amount from the nozzle can be adjusted by adjusting the rotation angle of a butterfly valve as a flow rate adjustment mechanism. However, when controlling the discharge amount from the nozzle by the flow rate adjustment mechanism, the pressure in the flow path upstream of the flow rate control mechanism is not stable, and it may take time for the discharge amount to stabilize.

Means for Solving the Problems

[0005] According to a first aspect of the present disclosure, a three-dimensional shaping apparatus is provided. The three-dimensional shaping apparatus includes a screw and a motor that rotates the screw, a plasticizing unit that plasticizes a material to generate a plasticized material, a nozzle that has a nozzle opening and discharges the plasticized material, and a control unit that controls the plasticizing unit. When the control unit adjusts the discharge amount of the plasticized material from the nozzle from a first discharge amount to a second discharge amount greater than the first discharge amount, the control unit first adjusts the rotation speed of the screw from a first speed to a second speed greater than the first speed, and then adjusts the rotation speed to a third speed greater than the first speed and less than the second speed (a first operation). When the control unit adjusts the discharge amount of the plasticized material from the nozzle from a third discharge amount to a fourth discharge amount less than the third discharge amount, the control unit first adjusts the rotation speed of the screw from a fourth speed to a fifth speed less than the fourth speed, and then adjusts the rotation speed to a sixth speed greater than the fifth speed and less than the fourth speed (a second operation). The control unit performs at least one of these operations.

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 apparatus 100 in the first embodiment. In FIG. 1, arrows along the X, Y, and Z directions orthogonal to each other are shown. The X, Y, and Z directions are directions along the X-axis, Y-axis, and Z-axis, which are three mutually orthogonal spatial axes, and include both the directions on one side along the X-axis, Y-axis, and Z-axis and the opposite directions. The X-axis and the Y-axis are axes along the horizontal plane, and the Z-axis is an axis along the vertical line. In other figures as well, arrows along the X, Y, and Z directions are appropriately shown. The X, Y, and Z directions in FIG. 1 represent the same directions as the X, Y, and Z directions in other figures. Hereinafter, the +Z direction is also referred to as "up" and the -Z direction is also referred to as "down".

[0008] The three-dimensional shaping apparatus 100 includes a control unit 101 that controls the three-dimensional shaping apparatus 100, a discharge unit 200 that generates and discharges a plasticized material, a shaping stage 210 that serves as a base for the three-dimensional shaped object, and a position changing unit 230 that controls the discharge position of the plasticized material.

[0009] Under the control of the control unit 101, the discharge unit 200 discharges the plasticized material, which is obtained by plasticizing the solid-state material into a paste state, onto the stage 210. The discharge unit 200 includes a material supply unit 20 that is a supply source of the material before being converted into the plasticized material, a plasticizing unit 30 that plasticizes at least a part of the material to generate the plasticized material, a flow path 69 through which the generated plasticized material flows, a nozzle 61 that communicates with the flow path 69 and discharges the plasticized material, a discharge control unit 70 provided in the flow path 69, and a suction and delivery unit 75 provided in the flow path 69. The flow path 69 communicates with a nozzle opening 62 of the nozzle 61 described later.

[0010] The material supply unit 20 stores materials in the form of pellets, powders, etc. In this embodiment, a thermoplastic resin formed into pellets is used as the material. Examples of such materials include ABS (acrylonitrile-butadiene-styrene), PEEK (polyetheretherketone), PP (polypropylene), etc. The material supply unit 20 in this embodiment is constituted by a hopper. Below the material supply unit 20, a supply path 22 that connects between the material supply unit 20 and the plasticizing unit 30 is provided. The material supply unit 20 supplies the material to the plasticizing unit 30 via the supply path 22.

[0011] The plasticizing unit 30 includes a screw case 31, a motor 32, a screw 40, and a barrel 50. The plasticizing unit 30 plasticizes at least a part of the material supplied from the material supply unit 20 to generate a paste-like plasticized material having fluidity. Then, the plasticizing unit 30 supplies the generated plasticized material to the nozzle 61. "Plasticization" is a concept that includes melting and means changing from a solid state to a state having fluidity. Specifically, in the case of a material that undergoes a glass transition, plasticization means raising the temperature of the material above the glass transition point. In the case of a material that does not undergo a glass transition, plasticization means raising the temperature of the material above the melting point. The screw 40 in this embodiment is sometimes called a flat screw or a scroll.

[0012] Figure 2 is a perspective view showing the schematic configuration of the screw 40. Figure 3 is a schematic plan view showing the barrel 50. The screw 40 has a substantially cylindrical shape in which the length in the axial direction, which is the direction along its central axis RX, is smaller than the length in the direction orthogonal to the axial direction. The screw 40 is arranged such that its central axis RX, which is the center of rotation, is parallel to the Z direction.

[0013] As shown in FIG. 1, the screw 40 is housed in the screw case 31. The upper surface 41 side of the screw 40 is connected to the motor 32. The screw 40 rotates within the screw case 31 by the rotational driving force generated by the motor 32. The screw 40 may be driven by the motor 32 via a speed reducer.

[0014] The rotational speed of the screw 40 is controlled by the control unit 101. When the control unit 101 increases the discharge amount of the plasticized material from the nozzle 61, it increases the rotational speed of the screw 40. When the control unit 101 decreases the discharge amount of the plasticized material from the nozzle 61, it decreases the rotational speed of the screw 40.

[0015] As shown in FIG. 2, a spiral groove portion 45 is formed on the lower surface 42 of the screw. The supply path 22 of the material supply unit 20 described above communicates with the groove portion 45 from the side surface 43 of the screw 40. The groove portion 45 continues to the material inlet 44 formed on the side surface 43 of the screw 40. The material inlet 44 is a portion that receives the material supplied through the supply path 22 of the material supply unit 20. As shown in FIG. 2, in this embodiment, the groove portion 45 is separated by the ridge portion 46 and formed in three. Note that the number of the groove portions 45 is not limited to three, and may be one or two, or four or more. The groove portion 45 is not limited to a spiral shape, and may be a helical shape, an involute curve shape, or a shape that extends in an arc from the central portion 47 toward the outer periphery.

[0016] As shown in FIG. 1, the barrel 50 is disposed below the screw 40. The upper surface 52 of the barrel faces the lower surface 42 of the screw, and a space is formed between the groove 45 on the lower surface 42 of the screw and the upper surface 52 of the barrel. As shown in FIG. 3, the barrel 50 is provided with a communication hole 56 that communicates with a nozzle 61 described later on the central axis RX of the screw 40. In the present embodiment, the communication hole 56 forms a part of the flow path 69 described above. The upper surface 52 of the barrel is formed with a plurality of guide grooves 54 that 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. The barrel 50 has a heater 58 built in at a position facing the groove 45 of the screw 40. The temperature of the heater 58 is controlled by the control unit 101.

[0017] The material supplied into the groove 45 of the screw 40 is plasticized in the groove 45 while flowing along the groove 45 by the rotation of the screw 40, and is led as a plasticized material to the central portion 47 of the screw 40. The paste-like plasticized material that has flowed into the central portion 47 and exhibits fluidity is supplied to the nozzle 61 through the communication hole 56. Note that in the plasticized material, not all types of substances constituting the plasticized material need to be plasticized. The plasticized 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 plasticized material.

[0018] As shown in FIG. 1, the nozzle 61 includes a nozzle flow path 65 and a tip surface 63 provided with a nozzle opening 62. The nozzle flow path 65 is a flow path for the plasticized material formed within the nozzle 61 and forms a part of the flow path 69 described above. The tip surface 63 is a surface that constitutes the tip portion of the nozzle 61 that protrudes in the -Z direction toward the shaping surface 211. The nozzle opening 62 is a portion where the flow path cross-section of the nozzle flow path 65 is reduced, provided at the end on the side of the nozzle flow path 65 that communicates with the atmosphere, that is, the end on the tip surface 63 side. The plasticized material generated by the plasticizing unit 30 is discharged from the nozzle opening 62 via the flow path 69. A heater for suppressing the temperature drop of the plasticized material discharged onto the stage 210 may be arranged around the nozzle 61.

[0019] The discharge control unit 70 controls the discharge of the plasticized material from the nozzle 61 by controlling the opening area of the flow path 69. The discharge control unit 70 in the present embodiment is constituted by a valve and is provided in the nozzle flow path 65. The discharge control unit 70 changes the opening degree of the nozzle flow path 65 by rotating within the nozzle flow path 65. The discharge control unit 70 is driven by a first drive unit 74 under the control of the control unit 101. The first drive unit 74 is constituted by, for example, a stepping motor. The control unit 101 controls the on / off of the outflow of the plasticized material by controlling the rotation angle of the valve using the first drive unit 74.

[0020] The suction and delivery unit 75 includes a branch flow path 76, a plunger 77, and a second drive unit 78. The branch flow path 76 is connected to the flow path 69 between the discharge control unit 70 and the nozzle opening 62, that is, to the portion of the flow path 69 between the discharge control unit 70 and the nozzle opening 62. In the present embodiment, the branch flow path 76 is formed by a cylinder connected to the nozzle flow path 65 and extends in the -X direction from the connection portion with the nozzle flow path 65. The plunger 77 is moved within the branch flow path 76 by being driven by the second drive unit 78 under the control of the control unit 101. The second drive unit 78 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 motion of the plunger 77.

[0021] The control unit 101 performs a suction operation and a delivery operation by controlling the suction and delivery unit 75 to change the position of the plunger 77. The suction operation refers to the operation of sucking the plasticized material in the flow path 69 into the branch flow path 76. The delivery operation refers to the operation of delivering the plasticized material sucked into the branch flow path 76 to the flow path 69. In the present embodiment, in the suction operation, the control unit 101 retracts the plunger 77 in a direction away from the flow path 69, and in the delivery operation, the control unit 101 advances the plunger 77 in a direction approaching the flow path 69.

[0022] The control unit 101 can suppress the trailing phenomenon in which the plasticized material droops from the nozzle opening 62 as if drawing a thread by performing the suction operation to reduce the pressure in the flow path 69. In this case, the control unit 101 can more effectively suppress the trailing phenomenon by performing the suction operation after setting the opening degree of the nozzle flow path 65 to zero by the discharge control unit 70. Further, the control unit 101 can enhance the responsiveness of the delivery of the plasticized material from the nozzle opening 62 by performing the delivery operation to increase the pressure in the flow path 69. For example, when starting the discharge from the nozzle 61, the control unit 101 can enhance the responsiveness of the delivery of the plasticized material by performing the delivery operation before increasing the opening degree of the nozzle flow path 65 to be greater than zero by the discharge control unit 70.

[0023] The stage 210 is arranged at a position facing the nozzle 61. The three-dimensional modeling device 100 forms a three-dimensional model by discharging a plasticized material from the nozzle opening 62 toward the modeling surface 211 of the stage 210 to laminate layers. The region where the three-dimensional model is formed, among the modeling surface 211 and the region above the modeling surface 211, is also referred to as the modeling region.

[0024] The position changing unit 230 changes the relative position between the nozzle 61 and the stage 210. In the present embodiment, the position changing unit 230 moves the stage 210 relative to the nozzle 61. Note that a change in the relative position of the nozzle 61 with respect to the stage 210 may also be simply referred to as the movement or scanning of the nozzle 61. In the present embodiment, for example, moving the stage 210 in the +X direction can be rephrased as moving the nozzle 61 in the -X direction. Also, the relative movement speed of the nozzle 61 with respect to the stage 210 is also referred to as the relative movement speed of the nozzle 61. Further, the relative movement speed of the nozzle 61 is also simply referred to as the movement speed or the moving speed of the nozzle 61. The position changing unit 230 in the present embodiment is constituted by a three-axis positioner that moves the stage 210 in the three-axis directions of the X, Y, and Z directions by the driving force of three motors. Each motor is driven under the control of the control unit 101. Note that the position changing unit 230 may be configured to move the nozzle 61 without moving the stage 210, instead of being configured to move the stage 210. Also, the position changing unit 230 may be configured to move both the stage 210 and the nozzle 61.

[0025] The control unit 101 is constituted by a computer including a processor 102, a storage device 103, and an input / output interface for inputting and outputting signals to and from the outside. In the present embodiment, the control unit 101 exhibits various functions such as a function of executing three-dimensional modeling processing for forming a three-dimensional model by the processor 102 executing programs and instructions stored in the storage device 103. Note that the control unit 101 may be constituted by a combination of a plurality of circuits instead of a computer.

[0026] In the three-dimensional shaping process, the control unit 101 controls the discharge unit 200 and the position changing unit 230 according to the shaping data to shape an object on the shaping area of the shaping surface 211. The shaping data includes shaping path data representing the movement path of the relative movement of the nozzle 61 with respect to the stage 210, and discharge amount data representing the discharge amount associated with the shaping path data. The discharge amount refers to the amount of the plasticized material discharged per unit time from the nozzle opening 62.

[0027] FIG. 4 is an explanatory diagram schematically showing how a three-dimensional object is shaped in the three-dimensional shaping apparatus 100. In the three-dimensional shaping apparatus 100, as described above, in the plasticizing unit 30, the solid-state material supplied to the groove portion 45 of the rotating screw 40 is plasticized to generate the plasticized material MM. The control unit 101 discharges the plasticized material MM from the nozzle 61 while changing the position of the nozzle 61 with respect 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 plasticized material MM discharged from the nozzle 61 is continuously deposited in the moving direction of the nozzle 61. By such scanning by the nozzle 61, a shaping portion linearly extending along the scanning path of the nozzle 61 is shaped. Thus, among the three-dimensional objects, a continuous shaping portion is also called a partial shaping object Op.

[0028] The control unit 101 repeats the above scanning by the nozzle 61 to form a layer ML. After forming one layer ML, the control unit 101 moves the position of the nozzle 61 with respect to the stage 210 in the Z direction. Then, the three-dimensional object is shaped by stacking another layer ML on the layer ML formed so far. When laminating the layers of the plasticized material, the control unit 101 discharges the plasticized material from the nozzle 61 while maintaining the distance between the nozzle 61 and the discharge target. The discharge target is the shaping surface 211 when discharging the plasticized material onto the shaping surface 211, and is the upper surface of the already discharged plasticized material when discharging the plasticized material onto the already discharged plasticized material. The distance between the nozzle 61 and the discharge target is sometimes also called a gap Gp.

[0029] The width of the above-described partial shaped object Op is also referred to as the line width, and the height of the partial shaped object Op is also referred to as the lamination pitch. The line width and the lamination pitch are determined by the size of the above-described gap Gp and the amount of the plasticized material discharged from the nozzle 61 per unit displacement amount. For example, when the gap Gp is small, compared with the case where the gap Gp is large, the plasticized material discharged from the nozzle 61 is pressed more against the discharge target by the nozzle 61, so the lamination pitch is small and the line width is large. The amount of the plasticized material discharged from the nozzle 61 per unit displacement amount is determined by the moving speed of the nozzle 61 and the discharge amount of the plasticized material.

[0030] FIG. 5 is a flowchart of a three-dimensional shaping process executed by the control unit 101. In step S110, the control unit 101 acquires shape data representing the shape of a three-dimensional shaped object from an external computer, a recording medium, or the like. The control unit 101 acquires shape data such as three-dimensional CAD data from the outside through, for example, a network or a recording medium.

[0031] In step S120, the control unit 101 generates shaping data for shaping the three-dimensional shaped object represented by the three-dimensional data based on the three-dimensional data acquired in step S110. More specifically, in step S120, the control unit 101 generates the above-described shaping path data and discharge amount data. In other embodiments, instead of executing steps S110 and S120 to generate the shaping data, the control unit 101 may acquire, from the outside through a network or a recording medium, the shaping data generated by, for example, an external information processing device.

[0032] In step S130, the control unit 101 determines the movement speed data and the discharge control parameters. The movement speed data represents the movement speed of the nozzle 61 in each movement path included in the shaping path data. The discharge control parameters represent the discharge amount of the plasticized material and the parameters for controlling the suction and delivery unit 75 in each movement path. The movement speed data and the discharge control parameters determined in step S130 may be included in the shaping data, or may be generated as data separate from the shaping data. Also, the movement speed data and the discharge control parameters may be generated by an external information processing device.

[0033] In step S140, the control unit 101 controls the discharge unit 200 and the position changing unit 230 based on the shaping data generated in step S120, and the movement speed data and the discharge control parameters generated in step S130, to shape one layer out of the plurality of layers constituting the three-dimensional shaped object. More specifically, in step S140, the control unit 101 shapes one or a plurality of partial shaped objects constituting one layer of the three-dimensional shaped object in the shaping region on the shaping surface 211. In step S140, the control unit 101 controls the discharge control unit 70 to keep the nozzle flow path 65 fully open, and while adjusting the discharge amount of the plasticized material by controlling the rotation speed of the screw 40 and controlling the plunger 77 by the suction and delivery unit 75, performs the shaping of the layer.

[0034] In step S150, the control unit 101 determines whether or not the shaping of all the layers of the three-dimensional shaped object has been completed. If the control unit 101 determines that the shaping of all the layers of the three-dimensional shaped object has not been completed, it returns the process to step S140 and executes the shaping of the next layer. If the control unit 101 determines that the shaping of all the layers has been completed, it ends the three-dimensional shaping process.

[0035] FIG. 6 is an explanatory diagram showing an example of a partial shaped object in the present embodiment. In FIG. 6, a part of the partial shaped object Op forming one layer of the three-dimensional shaped object is schematically shown. In FIG. 6, as the shaping sections for shaping the partial shaped object Op, a first shaping section Sc1, a second shaping section Sc2, and a third shaping section Sc3 are shown.

[0036] Figure 7 is a timing chart for explaining the moving speed data and the discharge control parameters in the present embodiment. In Figure 7, graphs showing the time change of the moving speed of the nozzle 61, the time change of the discharge amount, the time change of the rotational speed of the screw 40, and the time change of the position of the plunger 77 when forming the partial molded object Op shown in Figure 6 are respectively represented.

[0037] In the present embodiment, the control unit 101 can control the position changing unit 230 based on the moving speed data to change the moving speed of the nozzle 61 to at least a first moving speed v1 and a second moving speed v2. The second moving speed v2 is a moving speed greater than the first moving speed v1. For example, when forming the curved shaping sections Sc1 and Sc3 in Figure 6, the control unit 101 sets the moving speed of the nozzle 61 to the first moving speed v1, and when forming the linear shaping section Sc2, the control unit 101 sets the moving speed of the nozzle 61 to the second moving speed v2. That is, before the timing t1 shown in Figure 7, the shaping section Sc1 is formed, from the timing t1 to the timing t4, the shaping section Sc2 is formed, and after the timing t4, the shaping section Sc3 is formed. From the timing t1 to the timing t2 is an acceleration section where the moving speed of the nozzle 61 is accelerated, and from the timing t3 to the timing t4 is a deceleration section where the moving speed of the nozzle 61 is decelerated.

[0038] The control unit 101 suppresses the fluctuation of the width of the plasticized material deposited on the stage 210 by increasing the discharge amount of the plasticized material from the nozzle 61 as the moving speed of the nozzle 61 increases. For example, as shown in Figure 7, when the moving speed of the nozzle 61 is the first moving speed v1, the control unit 101 sets the discharge amount to the first discharge amount F1, and when the moving speed of the nozzle 61 is the second moving speed v2, the control unit 101 sets the discharge amount to the second discharge amount F2. The second discharge amount F2 is a discharge amount greater than the first discharge amount F1.

[0039] The control unit 101 adjusts the discharge amount of the plasticized material by controlling the rotation speed of the screw 40. In the present embodiment, when the control unit 101 adjusts the discharge amount of the plasticized material from the nozzle 61 from the first discharge amount F1 to the second discharge amount F2 based on the discharge control parameter, the control unit 101 adjusts the rotation speed of the screw 40 from the first speed R1 to the second speed R2, and then executes a "first operation" of adjusting it to the third speed. The second speed R2 is a speed higher than the first speed. The third speed R3 is a speed higher than the first speed R1 and lower than the second speed R2.

[0040] Further, when the control unit 101 adjusts the discharge amount of the plasticized material from the nozzle 61 from the third discharge amount F3 to the fourth discharge amount F4 smaller than the third discharge amount F3 based on the discharge control parameter, the control unit 101 adjusts the rotation speed of the screw 40 from the fourth speed R4 to the fifth speed R5, and then executes a "second operation" of adjusting it to the sixth speed R6. The fifth speed R5 is a speed lower than the second speed R2. The sixth speed R6 is a speed higher than the fifth speed R5 and lower than the fourth speed R4. In the present embodiment, the third discharge amount F3 is equal to the second discharge amount F2, and the fourth discharge amount F4 is equal to the first discharge amount F1. Also, the fourth speed R4 is equal to the third speed R3, and the sixth speed R6 is equal to the first speed R1.

[0041] As shown in FIG. 7, in the present embodiment, the control unit 101 executes the above-described first operation in an acceleration section where the relative movement speed of the nozzle 61 accelerates from the first movement speed v1 to the second movement speed v2. Further, the control unit 101 executes the above-described second operation in a deceleration section where the relative movement speed of the nozzle 61 decelerates from the second movement speed v2 to the first movement speed v1.

[0042] The control unit 101 controls the suction and delivery unit 75 to move the plunger 77 within the branch flow path 76, thereby performing a delivery operation of sending the plasticized material from the branch flow path 76 to the flow path 69 in the acceleration section, and a suction operation of sucking the plasticized material from the flow path 69 to the branch flow path 76 in the deceleration section. That is, in the acceleration section, the control unit 101 performs an operation of pushing the plunger 77 closer to the flow path 69, and in the deceleration section, the control unit 101 performs an operation of pulling the plunger 77 away from the flow path 69. The plunger position shown in FIG. 7 represents the position coordinates in the X direction of the end face 79 on the +X direction side of the plunger 77 shown in FIG. 1. In FIG. 7, when the plunger position is zero, the end face 79 of the plunger 77 is located closest to the flow path 69.

[0043] In the present embodiment, the control unit 101 matches a first movement amount D1, which is the movement amount of the plunger 77 in the acceleration section, and a second movement amount D2, which is the movement amount of the plunger 77 in the deceleration section. In FIG. 7, the first movement amount D1 and the second movement amount D2 are each shown with hatching. In the present disclosure, "matching" means that the difference between the first movement amount D1 and the second movement amount D2 falls within a range of 10%. Note that a range of 5% is more preferable for the difference between the first movement amount D1 and the second movement amount D2. It is even more preferable that the first movement amount D1 and the second movement amount D2 coincide.

[0044] In the present embodiment, when the control unit 101 executes the first operation in the acceleration section, the control unit 101 performs a process of transmitting an operation command for moving the plunger 77 to the suction and delivery unit 75 before the timing when the rotational speed of the screw 40 reaches the second speed R2. Specifically, in the present embodiment, the control unit 101 transmits an operation command for causing the suction and delivery unit 75 to execute a delivery operation on the plunger 77 simultaneously with the timing t1 when the acceleration of the rotational speed starts.

[0045] In the present embodiment, when the control unit 101 executes the second operation in the deceleration section, it performs a process of transmitting an operation command for moving the plunger 77 to the suction and delivery unit 75 before the timing when the rotational speed of the screw 40 reaches the fifth speed R5. Specifically, in the present embodiment, the control unit 101 transmits an operation command for executing a suction operation on the plunger 77 to the suction and delivery unit 75 at the same timing t3 as the start of the deceleration of the rotational speed.

[0046] In the storage device 103 provided in the control unit 101, the moving speed of the nozzle 61, the discharge amount, the rotational speed of the screw 40, and the position of the plunger 77 are stored by functions or maps so as to have the relationship shown in FIG. 7. In step S130 described above, the control unit 101 determines the moving speed data and the discharge control parameters using the functions or maps stored in the storage device 103, thereby controlling the discharge of the plasticized material so that the line width does not change even if the moving speed of the nozzle 61 changes.

[0047] FIG. 8 is a graph showing the simulation result of the pressure change in the flow path 69 by the first operation described above. FIG. 8 shows the experimental result of executing the first operation described above for the rotational speed of the screw 40, and as a comparative example, shows the experimental result of an operation of directly changing the rotational speed of the screw 40 from the first speed R1 to the third speed R3 without passing through the second speed R2, which is different from the first operation. In the comparative example, even when the rotational speed of the screw 40 was increased from the first speed to the third speed, the pressure of the plasticized material in the flow path 69 did not immediately increase but increased gently. On the other hand, by the first operation, when the rotational speed of the screw 40 was once changed to the second speed R2, which is higher than the first speed R1 and the third speed R3, before changing from the first speed R1 to the third speed R3, the pressure of the plasticized material in the flow path 69 increased much faster than in the comparative example and then quickly stabilized.

[0048] When the three-dimensional shaping apparatus 100 of the present embodiment described above adjusts the discharge amount of the plasticized material from the first discharge amount to a second discharge amount larger than the first discharge amount, it executes a first operation. In the first operation, after adjusting the rotation speed of the screw 40 from the first speed R1 to a second speed R2 larger than the first speed R1, it is adjusted to a third speed R3 that is larger than the first speed R1 and smaller than the second speed R2. Therefore, when increasing the discharge amount, the discharge amount can be quickly stabilized. Further, when the three-dimensional shaping apparatus 100 adjusts the discharge amount of the plasticized material from the third discharge amount to a fourth discharge amount smaller than the third discharge amount, it executes a second operation. In the second operation, after adjusting the rotation speed of the screw 40 from the fourth speed R4 to a fifth speed R5 smaller than the fourth speed R4, it is adjusted to a sixth speed R6 that is larger than the fifth speed R5 and smaller than the fourth speed R4. Therefore, when decreasing the discharge amount, the discharge amount can be quickly stabilized.

[0049] Further, in the acceleration section where the relative movement speed of the nozzle 61 of the three-dimensional shaping apparatus 100 of the present embodiment accelerates from the first movement speed v1 to the second movement speed v2, an operation of executing the first operation is performed, and in the deceleration section where the speed decelerates from the second movement speed v2 to the first movement speed v1, an operation of executing the second operation is performed. Then, the three-dimensional shaping apparatus 100 moves the plunger 77 in the branch flow path 76, thereby performing an operation of sending the plasticized material from the branch flow path 76 to the flow path 69 in the acceleration section and an operation of sucking the plasticized material from the flow path 69 to the branch flow path 76 in the deceleration section. At this time, the three-dimensional shaping apparatus 100 matches the movement amount of the plunger 77 in the acceleration section with the movement amount of the plunger 77 in the deceleration section. Thereby, it is possible to suppress a bias from occurring in the movement amount in the direction in which the plunger 77 approaches the flow path 69 and the movement amount in the direction in which the plunger 77 moves away from the flow path 69. As a result, the position of the plunger 77 can be accurately controlled over a long period. As a result, the shaping accuracy of the three-dimensional shaped object can be improved.

[0050] Further, when the three-dimensional shaping apparatus 100 of the present embodiment executes the first operation in the acceleration section, before the timing of changing the rotation speed of the screw 40 to the second speed R2, it executes a process of transmitting an operation command for moving the plunger 77 to the suction and delivery section 75. Therefore, when the nozzle 61 is accelerating, the plasticized material can be quickly supplied into the flow path 69. As a result, it is possible to suppress a decrease in the discharge amount and a temporary narrowing of the line width when the nozzle 61 is accelerating. Further, when the three-dimensional shaping apparatus 100 executes the second operation in the deceleration section, before the timing of changing the rotation speed of the screw 40 to the fifth speed R5, it executes a process of transmitting an operation command for moving the plunger 77 to the suction and delivery section 75. Therefore, when the nozzle 61 is decelerating, the plasticized material can be quickly sucked from the flow path 69. As a result, it is possible to suppress an excessive discharge amount and a temporary widening of the line width when the nozzle 61 is decelerating.

[0051] B. Second Embodiment: The configuration of the three-dimensional shaping apparatus 100 in the second embodiment is the same as that of the three-dimensional shaping apparatus 100 in the first embodiment. In the first embodiment and the second embodiment, the control content of the rotation speed of the screw 40 in the first operation is different, and the other control contents are the same as those in the first embodiment.

[0052] FIG. 9 is a diagram showing the change over time of the rotation speed of the screw 40 in the second embodiment. In the second embodiment, in the first operation, the control unit 101 adjusts the rotation speed of the screw 40 from the first speed R1 to the second speed R2, then to the seventh speed R7 which is smaller than the second speed R2 and larger than the third speed R3, and then adjusts it from the seventh speed R7 to the third speed R3.

[0053] According to the second embodiment described above, since the rotational speed of the screw 40 can be gradually decelerated from the second speed R2 to the third speed R3 via the seventh speed R7, when reducing the rotational speed of the screw 40 from the second speed R2 to the third speed R3, it is possible to suppress the occurrence of an undershoot phenomenon in which the pressure of the plasticized material in the flow path 69 drops excessively as shown by the dashed line in FIG. 10. Therefore, when reducing the rotational speed of the screw 40 in the first operation, the discharge amount can be quickly stabilized.

[0054] In this embodiment, the control unit 101 decelerates the rotational speed of the screw 40 from the second speed R2 to the third speed R3 via the seventh speed R7. That is, the control unit 101 reduces the rotational speed of the screw 40 in two steps. In contrast, the control unit 101 may reduce the rotational speed of the screw 40 in three or more steps.

[0055] Also, as shown by the dashed line in FIG. 9, in the second operation, the control unit 101 may adjust the rotational speed of the screw 40 from the fourth speed R4 to the fifth speed R5, then adjust it to an eighth speed R8 that is greater than the fifth speed R5 and less than the sixth speed R6, and then adjust it from the eighth speed R8 to the sixth speed R6. By doing so, it is easy to stabilize the discharge amount when increasing the rotational speed of the screw 40 from the fifth speed R5 to the sixth speed R6.

[0056] C. Third Embodiment: The configuration of the three-dimensional shaping apparatus 100 in the third embodiment is the same as that of the three-dimensional shaping apparatus 100 in the first embodiment. In the third embodiment, the control of the moving speed of the nozzle 61 is different from that in the first embodiment.

[0057] FIG. 11 is a diagram showing the change over time of the moving speed of the nozzle 61 in the third embodiment. In the third embodiment, as shown in FIG. 11, the control unit 101 accelerates the relative moving speed of the nozzle 61 from the first moving speed v1 to the second moving speed v2, and then further accelerates it to a third moving speed v3 that is greater than the second moving speed v2. That is, in the third embodiment, the control unit 101 increases the moving speed of the nozzle 61 multiple times.

[0058] In this way, when the moving speed of the nozzle 61 is increased multiple times, when the control unit 101 decelerates the moving speed of the nozzle 61 from the third moving speed v3 to the first moving speed v1, it does not directly reduce the moving speed from the third moving speed v3 to the first moving speed v1. Instead, it first decelerates the moving speed from the third moving speed v3 to the second moving speed v2, and then decelerates from the second moving speed v2 to the first moving speed v1.

[0059] In the third embodiment, similar to the first embodiment, the control unit 101 moves the plunger 77 within the branch flow path 76 to perform an operation of sending the plasticized material from the branch flow path 76 to the flow path 69 in the acceleration section and an operation of sucking the plasticized material from the flow path 69 to the branch flow path 76 in the deceleration section. When performing such control of the plunger 77, as shown in FIG. 11, if deceleration is performed step by step in the same way as when the nozzle 61 is accelerating, the total amount of movement of the plunger 77 in the acceleration section and the total amount of movement of the plunger 77 in the deceleration section can be easily matched. As a result, it is possible to suppress a bias in the amount of movement of the plunger 77 in the direction approaching the flow path 69 and the amount of movement of the plunger 77 in the direction away from the flow path 69. As a result, even when the moving speed of the nozzle 61 is changed in multiple stages, the position of the plunger 77 can be accurately controlled over a long period. As a result, the shaping accuracy of the three-dimensional shaped object can be improved.

[0060] D. Other Embodiments: (D1) In the above-described embodiment, the control unit 101 executes both the first operation and the second operation in the three-dimensional shaping process. In contrast, the control unit 101 may execute only one of the first operation and the second operation.

[0061] (D2) In the above-described embodiment, the control unit 101 performs the feeding operation of the plunger 77 together with the first operation in the acceleration section of the nozzle 61, and performs the suction operation of the plunger 77 together with the second operation in the deceleration section of the nozzle 61. In contrast, the control unit 101 may not perform either the feeding operation or the suction operation of the plunger 77. Further, the control unit 101 may not perform both the feeding operation and the suction operation of the plunger 77. When neither the feeding operation nor the suction operation is performed, the three-dimensional shaping apparatus 100 may not include the plunger 77.

[0062] (D3) In the above-described embodiment, the control unit 101 performs both the process of transmitting an operation command for moving the plunger 77 to the suction and feeding unit 75 before the timing when the rotation speed of the screw 40 reaches the second speed R2, and the process of transmitting an operation command for moving the plunger 77 to the suction and feeding unit 75 before the timing when the rotation speed of the screw 40 reaches the fifth speed R5. In contrast, the control unit 101 may execute only one of these processes, or may not execute both processes.

[0063] (D4) In the above embodiment, the screw 40 is configured as a flat screw. In contrast, the screw 40 may not be configured as a flat screw and may be configured as an in-line screw.

[0064] E. 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.

[0065] (1) According to a first aspect of the present disclosure, a three-dimensional shaping apparatus is provided. This three-dimensional shaping apparatus has a screw and a motor for rotating the screw, and a plasticizing unit that plasticizes a material to generate a plasticized material, a nozzle having a nozzle opening for discharging the plasticized material, and a control unit for controlling the plasticizing unit. When the control unit adjusts the discharge amount of the plasticized material from the nozzle from a first discharge amount to a second discharge amount greater than the first discharge amount, the control unit adjusts the rotation speed of the screw from a first speed to a second speed greater than the first speed, and then adjusts it to a third speed greater than the first speed and less than the second speed. When the discharge amount of the plasticized material from the nozzle is adjusted from a third discharge amount to a fourth discharge amount smaller than the third discharge amount, the control unit adjusts the rotation speed of the screw from a fourth speed to a fifth speed smaller than the fourth speed, and then adjusts it to a sixth speed greater than the fifth speed and less than the fourth speed. At least one of the first operation and the second operation is executed. According to such a configuration, when the discharge amount is changed, the discharge amount after the change can be quickly stabilized.

[0066] (2) In the above aspect, in the first operation, the control unit may adjust the rotation speed of the screw to a seventh speed smaller than the second speed and greater than the third speed after adjusting it to the second speed, and then adjust it from the seventh speed to the third speed. According to such a configuration, it is possible to suppress the occurrence of an undershoot phenomenon in which the pressure of the plasticized material in the flow path excessively decreases.

[0067] (3) In the above-described embodiment, the plasticizing material flows, and includes a flow path communicating with the nozzle opening, a branch flow path connected to the flow path, and a plunger disposed in the branch flow path. By changing the position of the plunger, the plasticizing material in the flow path can be sucked into the branch flow path, and the plasticizing material in the branch flow path can be sent out to the flow path. The suction and delivery unit is configured to be capable of this. The control unit executes at least one of the operations of executing the first operation in an acceleration section where the relative movement speed of the nozzle accelerates from a first movement speed to a second movement speed greater than the first movement speed, or executing the second operation in a deceleration section where the relative movement speed of the nozzle decelerates from the second movement speed to the first movement speed. By moving the plunger in the branch flow path, an operation of sending the plasticizing material from the branch flow path to the flow path in the acceleration section and an operation of sucking the plasticizing material from the flow path into the branch flow path in the deceleration section are executed. The movement amount of the plunger in the acceleration section and the movement amount of the plunger in the deceleration section may be matched. According to such a configuration, the position of the plunger can be accurately controlled over a long period, so that the shaping accuracy of the three-dimensional shaped object can be improved.

[0068] (4) In the above-described embodiment, when the control unit executes the first operation in the acceleration section, a process of transmitting an operation command for moving the plunger to the suction and delivery unit before the timing when the rotation speed of the screw reaches the second speed, or when the control unit executes the second operation in the deceleration section, a process of transmitting an operation command for moving the plunger to the suction and delivery unit before the timing when the rotation speed of the screw reaches the fifth speed, may be performed at least one of them. According to such a configuration, it is possible to suppress the occurrence of insufficient discharge amount or excessive discharge amount when the movement speed of the nozzle is accelerating or decelerating.

[0069] (5) In the above-described embodiment, the control unit accelerates the relative movement speed of the nozzle from the first movement speed to the second movement speed, and then further accelerates it to a third movement speed greater than the second movement speed. When decelerating the movement speed from the third movement speed to the first movement speed, the movement speed may be first decelerated from the third movement speed to the second movement speed and then decelerated from the second movement speed to the first movement speed. According to such an embodiment, according to such an embodiment, even when changing the movement speed of the nozzle in multiple stages, the position of the plunger can be accurately controlled over a long period of time, so that the shaping accuracy of the three-dimensional shaped object can be improved.

[0070] The present disclosure is not limited to the form as the three-dimensional shaping apparatus described above, and can be realized in various forms such as a method for manufacturing a three-dimensional shaped object, 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

[0071] 20... Material supply unit, 22... Supply path, 30... Plasticizing unit, 31... Screw case, 32... Motor, 40... Screw, 41... Upper surface, 42... Screw lower surface, 43... Side surface, 44... Material inlet, 45... Groove portion, 46... Ridge portion, 47... Central portion, 50... Barrel, 52... Barrel upper surface, 54... Guide groove, 56... Communication hole, 58... Heater, 61... Nozzle, 62... Nozzle opening, 63... Tip surface, 65... Nozzle flow path, 69... Flow path, 70... Discharge control unit, 74... First drive unit, 75... Suction and delivery unit, 76... Branch flow path, 77... Plunger, 78... Second drive unit, 79... End surface, 100... Three-dimensional shaping apparatus, 101... Control unit, 102... Processor, 103... Storage device, 200... Discharge unit, 210... Stage, 211... Shaping surface, 230... Position changing unit

Claims

1. A plasticizing unit having a screw and a motor for rotating the screw, for plasticizing a material to produce a plasticized material; A nozzle having a nozzle opening for discharging the plasticized material; A control unit for controlling the plasticizing unit, comprising: The control unit: When adjusting the discharge amount of the plasticized material from the nozzle from a first discharge amount to a second discharge amount greater than the first discharge amount, after adjusting the rotation speed of the screw from a first speed to a second speed greater than the first speed, adjusting it to a third speed greater than the first speed and less than the second speed; or a first operation, When adjusting the discharge amount of the plasticized material from the nozzle from a third discharge amount to a fourth discharge amount less than the third discharge amount, after adjusting the rotation speed of the screw from a fourth speed to a fifth speed less than the fourth speed, adjusting it to a sixth speed greater than the fifth speed and less than the fourth speed; a second operation, Performing at least one of the operations; A three-dimensional shaping device.

2. The three-dimensional shaping device according to claim 1, In the first operation, the control unit adjusts the rotation speed of the screw to a seventh speed less than the second speed and greater than the third speed after adjusting it to the second speed, and then adjusts it from the seventh speed to the third speed. A three-dimensional shaping device.

3. The three-dimensional shaping device according to claim 1, A flow path through which the plasticized material flows and communicates with the nozzle opening; A branch flow path connected to the flow path, and a plunger disposed in the branch flow path. By changing the position of the plunger, the plasticized material in the flow path can be sucked into the branch flow path, and the plasticized material in the branch flow path can be sent to the flow path. A suction and delivery unit configured to be capable of doing so; The control unit: Performing the first operation in an acceleration section where the relative movement speed of the nozzle accelerates from a first movement speed to a second movement speed greater than the first movement speed; or an operation, Performing the second operation in a deceleration section where the speed decelerates from the second movement speed to the first movement speed; Performing at least one of the operations; By moving the plunger within the branch flow path, an operation of sending the plasticized material from the branch flow path to the flow path in the acceleration section and an operation of sucking the plasticized material from the flow path into the branch flow path in the deceleration section are executed. Match the amount of movement of the plunger in the acceleration section with the amount of movement of the plunger in the deceleration section. Three-dimensional shaping apparatus.

4. The three-dimensional shaping apparatus according to claim 3, wherein the control unit when executing the first operation in the acceleration section, a process of transmitting an operation command for moving the plunger to the suction / delivery unit before the timing when the rotational speed of the screw reaches the second speed, or when executing the second operation in the deceleration section, a process of transmitting an operation command for moving the plunger to the suction / delivery unit before the timing when the rotational speed of the screw reaches the fifth speed, performs at least one of the above. Three-dimensional shaping apparatus.

5. The three-dimensional shaping apparatus according to claim 3, wherein the control unit accelerates the relative movement speed of the nozzle from the first movement speed to the second movement speed, and then further accelerates it to a third movement speed greater than the second movement speed, when decelerating the movement speed from the third movement speed to the first movement speed, the movement speed is first decelerated from the third movement speed to the second movement speed and then decelerated from the second movement speed to the first movement speed. Three-dimensional shaping apparatus.

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