阅读说明：本技术 三维造型装置 (Three-dimensional modeling apparatus ) 是由 渡部学 冈本英司 角谷彰彦 藤森康司 中村和英 于 2020-11-24 设计创作，主要内容包括：本公开提供一种抑制三维造型物的表面变粗糙的情况的三维造型装置。本公开的通过将材料的层进行层叠而对三维造型物进行造型的三维造型装置具备：载物台；喷出部,其具有被形成有喷嘴孔的喷嘴面；移动部,其使载物台与喷嘴面之间的相对位置发生变化；控制部,其对移动部进行控制。控制部以使从喷出部喷出材料时的载物台或材料的层与喷嘴面之间的间隔G、和喷嘴面的外径Dp的关系满足下式(1)的方式来驱动移动部,所述式(1)为,Dp≤20×G+0.20[mm]。(The present disclosure provides a three-dimensional modeling apparatus that suppresses surface roughening of a three-dimensional modeled object. The disclosed three-dimensional modeling device for modeling a three-dimensional modeled object by laminating material layers includes: an object stage; an ejection section having a nozzle surface on which a nozzle hole is formed; a moving part which changes the relative position between the objective table and the nozzle surface; and a control unit for controlling the moving unit. The control unit drives the moving unit so that a relationship between a distance G between the stage or the material layer and the nozzle surface when the material is ejected from the ejection unit and an outer diameter Dp of the nozzle surface satisfies the following expression (1), wherein Dp is less than or equal to 20 XG +0.20[ mm ].)

1. A three-dimensional modeling apparatus for modeling a three-dimensional modeled object by laminating material layers, the apparatus comprising:

an object stage;

an ejection section having a nozzle surface on which a nozzle hole is formed;

a moving unit that changes a relative position between the stage and the nozzle surface;

a control unit that controls the moving unit,

the control unit drives the moving unit so that a relationship between a distance G between the stage or the material layer and the nozzle surface when the material is ejected from the ejection unit and an outer diameter Dp of the nozzle surface satisfies the following expression (1),

the formula (1) is that Dp is less than or equal to 20 XG +0.20[ mm ].

2. The three-dimensional modeling apparatus of claim 1,

the control section drives the moving section such that a relationship between an inner diameter Dh of the nozzle hole and the gap G satisfies the following expression (2),

in the formula (2), G is more than 0 and less than or equal to Dh.

3. The three-dimensional modeling apparatus of claim 1 or 2,

the control unit drives the moving unit so that the gap G satisfies the following expression (3),

the G in the formula (3) is more than or equal to 0.05mm and less than or equal to 0.20 mm.

4. The three-dimensional modeling apparatus of claim 1,

the discharge portion is configured such that an outer diameter Dp of the nozzle surface satisfies the following formula (4),

dp is more than or equal to 0.50[ mm ] and less than or equal to 2.20[ mm ] in the formula (4).

Technical Field

The present disclosure relates to a three-dimensional modeling apparatus.

Background

Patent document 1 describes an apparatus for forming a three-dimensional shaped object by laminating a molten material discharged from a nozzle on a forming table.

In the above apparatus, the three-dimensional shaped object having a smooth surface can be shaped by reducing the distance between the stage or the material layer and the nozzle when the material is ejected from the nozzle onto the stage or the material layer. However, the inventors of the present application have found that when the above-described interval is narrowed, the nozzle interferes with the three-dimensional shaped object in the shaping, and the surface of the three-dimensional shaped object may be roughened.

Patent document 1: japanese patent laid-open publication No. 2018-187777

Disclosure of Invention

According to one embodiment of the present disclosure, there is provided a three-dimensional modeling apparatus for modeling a three-dimensional modeled object by laminating material layers. The three-dimensional modeling apparatus includes: an object stage; an ejection section having a nozzle surface on which a nozzle hole is formed; a moving unit that changes a relative position between the stage and the nozzle surface; and a control unit that controls the moving unit. The control unit drives the moving unit so that a relationship between a distance G between the stage or the material layer and the nozzle surface when the material is ejected from the ejection unit and an outer diameter Dp of the nozzle surface satisfies the following expression (1), where Dp is less than or equal to 20 XG +0.20[ mm ]

Drawings

Fig. 1 is an explanatory diagram showing a schematic configuration of a three-dimensional modeling apparatus.

Fig. 2 is a perspective view showing the structure of the flat spiral.

Fig. 3 is a top view showing the structure of the cylinder.

Fig. 4 is a perspective view showing the structure of the nozzle.

Fig. 5 is a flowchart showing the content of the modeling process.

Fig. 6 is an explanatory view schematically showing a case where a three-dimensional shaped object is shaped.

Fig. 7 is a sectional view taken along line VII-VII in fig. 6.

Fig. 8 is a table showing test results for examining the dimensional accuracy of a three-dimensional shaped object.

Fig. 9 is an image showing the appearance of sample S1.

Fig. 10 is an image showing the appearance of sample S10.

Fig. 11 is an image showing the appearance of sample S12.

Fig. 12 is a graph showing the test results of examining the dimensional accuracy of a three-dimensional shaped object.

Fig. 13 is an explanatory view schematically showing a case where the nozzle interferes with the three-dimensional shaped object in shaping.

Detailed Description

A. The first embodiment:

fig. 1 is an explanatory diagram showing a schematic configuration of a three-dimensional modeling apparatus 100 according to a first embodiment. In fig. 1, arrow marks along mutually orthogonal X, Y, Z directions are shown. The X direction and the Y direction are directions along the horizontal direction, and the Z direction is a direction along the vertical direction. Arrow labels in the direction X, Y, Z are shown as appropriate, even in other figures. The X, Y, Z direction in fig. 1 and the X, Y, Z direction in the other figures represent the same direction.

The three-dimensional modeling apparatus 100 according to the present embodiment includes a modeling unit 200, a stage 300, a moving unit 400, and a control unit 500. The molding unit 200 has a nozzle surface 63, and a nozzle hole 62 is provided in the nozzle surface 63. The three-dimensional modeling apparatus 100, under the control of the control unit 500, ejects the modeling material from the nozzle holes 62 while changing the relative position between the nozzle surface 63 and the stage 300, thereby layering layers of the modeling material on the stage 300 and modeling a three-dimensional modeled object of a desired shape. The molding material may be referred to as a molten material. The specific structure of the molding unit 200 will be described below.

The stage 300 has a modeling surface 310 facing the nozzle surface 63. On the shaping surface 310, a three-dimensional shaped object is shaped. In the present embodiment, the shaping surface 310 is provided so as to be parallel to the horizontal direction, that is, the direction X, Y. The stage 300 is supported by the moving unit 400.

The moving unit 400 changes the relative position between the nozzle surface 63 and the shaping surface 310. In the present embodiment, the moving unit 400 moves the stage 300 to change the relative position between the nozzle surface 63 and the modeling surface 310. The moving unit 400 in the present embodiment is composed of a three-axis positioner that moves the stage 300 in three axial directions, i.e., the X, Y, Z direction, by the power generated by three motors. Each motor is driven under the control of the control part 500. The moving unit 400 may be configured to change the relative position between the nozzle surface 63 and the modeling surface 310 by moving the modeling unit 200 without moving the stage 300. The moving unit 400 may be configured to change the relative position between the nozzle surface 63 and the modeling surface 310 by moving both the stage 300 and the modeling unit 200.

The control unit 500 is constituted by a computer including one or more processors, a main storage device, and an input/output interface for inputting and outputting signals to and from the outside. In the present embodiment, the control unit 500 executes a program or a command read into the main storage device by the processor to control the operations of the modeling unit 200 and the moving unit 400, thereby executing a modeling process for modeling a three-dimensional shaped object. The operation includes an operation of changing the three-dimensional relative position between the modeling unit 200 and the stage 300. The control unit 500 may be constituted by a combination of a plurality of circuits, instead of a computer.

The molding unit 200 includes a material supply portion 20 as a supply source of the material MR, a plasticizing portion 30 that plasticizes the material MR to become a molding material, and a discharge portion 60 having the above-described nozzle hole 62 and nozzle surface 63. "plasticization" means melting a thermoplastic material by applying heat thereto. The term "melt" means not only that the thermoplastic material is heated to a temperature equal to or higher than the melting point and becomes liquid, but also that the thermoplastic material is heated to a temperature equal to or higher than the glass transition point and softened to exhibit fluidity.

The material supply unit 20 supplies the material MR for producing the modeling material to the plasticizing unit 30. In the present embodiment, ABS resin formed in a granular shape is used as the material MR. In the present embodiment, the material supply unit 20 is configured as a hopper that stores the material MR. Below the material supply portion 20, a supply passage 22 that connects between the material supply portion 20 and the plasticizing portion 30 is provided. The material MR accommodated in the material supply portion 20 is supplied to the plasticizing portion 30 via the supply passage 22.

The plasticizing unit 30 plasticizes the material MR supplied from the material supply unit 20 to form a molding material, and supplies the molding material to the ejection unit 60. The plasticizing unit 30 includes a screw housing 31, a drive motor 32, a flat screw 40, a cylinder 50, and a heating unit 58. The screw casing 31 is a housing for accommodating the flat screw 40. A cylinder 50 is fixed to the lower end of the screw casing 31, and a flat screw 40 is accommodated in a space surrounded by the screw casing 31 and the cylinder 50.

The flat spiral 40 has a substantially cylindrical shape having a height in the direction of its central axis RX smaller than the diameter. The flat screw 4 is disposed in the screw case 31 such that the central axis RX is parallel to the Z direction. The drive motor 32 is connected to the upper surface 41 side of the flat screw 40, and the flat screw 40 is rotated about the central axis RX in the screw housing 31 by the torque generated by the drive motor 32. The flat screw 40 has a groove forming surface 42 formed with a groove portion 45 at the opposite side to the upper surface 41. The barrel 50 has a screw facing surface 52 that is opposite the slot forming surface 42 of the flat screw 40. A through hole 56 communicating with the discharge portion 60 is provided at the center of the screw facing surface 52.

Fig. 2 is a perspective view showing the structure of the flat screw 40. In fig. 2, the flat spiral 40 is shown upside down from fig. 1 for ease of understanding the technique. In fig. 2, the position of the central axis RX of the flat spiral 40 is shown by a single-dot chain line. The central portion 47 of the groove forming surface 42 of the flat screw 40 is configured as a recess for connecting one end of the groove portion 45. The central portion 47 is opposed to the through hole 56 of the cylinder 50 shown in fig. 1. The central portion 47 intersects the central axis RX. In the present embodiment, the groove 45 extends spirally from the central portion 47 toward the outer periphery of the flat screw 40 so as to describe an arc. The groove 45 may be formed to extend spirally. The groove forming surface 42 is provided with a ridge 46 that constitutes a side wall of the groove 45 and extends along each groove 45. The groove 45 is continuous to the material introduction port 44 formed in the side surface 43 of the flat spiral 40. The material introduction port 44 is a portion that receives the material MR supplied through the supply path 22 of the material supply unit 20. The material MR introduced into the groove portion 45 from the material introduction port 44 is conveyed toward the central portion 47 in the groove portion 45 by the rotation of the flat spiral 40.

In fig. 2, a flat spiral 40 having three grooves 45 and three ridges 46 is shown. The number of the groove portions 45 or the ridge portions 46 provided on the flat spiral 40 is not limited to three. The flat spiral 40 may be provided with only one groove 45, or may be provided with two or more grooves 45. In addition, any number of the raised strips 46 may be provided in accordance with the number of the grooves 45. In fig. 2, the flat spiral 40 having the material introduction port 44 formed at three locations is shown. The positions of the material introduction port 44 provided in the flat spiral 40 are not limited to three positions. The flat spiral 40 may be provided with the material introduction port 44 only at one location, or may be provided with the material introduction port 44 at two or more locations.

Fig. 3 is a top view showing the structure of the cylinder 50. As described above, the through hole 56 communicating with the ejection portion 60 is formed in the center of the screw facing surface 52. A plurality of guide grooves 54 are formed around the through-hole 56 of the screw facing surface 52. One end of each guide groove 54 is connected to the through-hole 56, and extends spirally from the through-hole 56 toward the outer periphery of the screw facing surface 52. Each guide groove 54 has a function of guiding the molding material to the through-hole 56. The guide groove 54 may not be provided on the screw facing surface 52.

As shown in fig. 1, a heating unit 58 for heating the material MR is embedded in the cylinder 50. The heating section 58 may be disposed, for example, below the cylinder 50 without being embedded in the cylinder 50. In the present embodiment, the heating unit 58 is configured by a heater that generates heat upon receiving supply of electric power. The temperature of the heating portion 58 is controlled by the control portion 500. The material MR conveyed in the groove portion 45 is plasticized by shearing due to the rotation of the flat screw 40 and heat from the heating portion 58, and becomes a pasty molding material. The molding material is supplied from the through-hole 56 to the ejection portion 60.

The ejection unit 60 ejects the molding material supplied from the plasticizing unit 30. The discharge unit 60 includes a nozzle 61, a flow path 65, and an opening/closing mechanism 70. The nozzle 61 is provided at a lower end portion of the ejection portion 60. The nozzle 61 has the nozzle face 63 and the nozzle hole 62 described above. The flow passage 65 communicates with the through hole 56 of the cylinder 50 and the nozzle hole 62, and allows the molding material to flow from the through hole 56 toward the nozzle hole 62. The molding material flowing through the flow channel 65 is ejected from the nozzle hole 62.

Fig. 4 is a perspective view showing the structure of the nozzle 61. In the present embodiment, the nozzle 61 has a circular nozzle face 63 centered on the central axis CL and a circular nozzle hole 62 centered on the central axis CL. In the present embodiment, the inner diameter Dh of the nozzle hole 62 is 0.20mm, and the outer diameter Dp of the nozzle face 63 is 0.50 mm.

As shown in fig. 1, the opening/closing mechanism 70 opens and closes the flow path 65 to control the ejection of the molding material from the nozzle hole 62. In the present embodiment, the opening/closing mechanism 70 is configured by a butterfly valve. The opening/closing mechanism 70 includes a drive shaft 72 as a shaft-like member, a valve body 73 that opens and closes the flow passage 65 in accordance with rotation of the drive shaft 72, and a valve driving unit 74 that rotates the drive shaft 72.

The drive shaft 72 is installed in the middle of the flow path 65 so as to intersect the flow direction of the molding material. In the present embodiment, the drive shaft 72 is attached in parallel with the Y direction, which is a direction perpendicular to the flow direction of the modeling material in the flow path 65. The drive shaft 72 can rotate about a central axis along the Y direction.

The valve body 73 is a plate-like member that rotates in the flow passage 65. In the present embodiment, the valve body 73 is formed by processing a portion disposed in the flow passage 65 of the drive shaft 72 into a plate shape. The shape of the valve body 73 when viewed in a direction perpendicular to the plate surface thereof substantially coincides with the opening shape of the flow passage 65 at the portion where the valve body 73 is disposed.

The valve driving unit 74 rotates the drive shaft 72 under the control of the control unit 500. The valve driving unit 74 is configured by, for example, a stepping motor. The valve body 73 is rotated in the flow passage 65 by the rotation of the drive shaft 72.

When the plate surface of the valve body 73 is held perpendicular to the direction of the molding material flow in the flow path 65 by the valve driving unit 74, the supply of the molding material from the flow path 65 to the nozzle 61 is blocked, and the discharge of the molding material from the nozzle 61 is stopped. When the drive shaft 72 is rotated by the valve drive unit 74 so that the plate surface of the valve body 73 is held at an acute angle with respect to the direction in which the molding material flows in the flow path 65, the supply of the molding material from the flow path 65 to the nozzle 61 is started, and the molding material is discharged from the nozzle 61 in a discharge amount corresponding to the rotation angle of the valve body 73. As shown in fig. 1, when the plate surface of the valve body 73 is held parallel to the direction of the molding material flow in the flow path 65 by the valve driving unit 74, the flow path resistance of the flow path 65 is the lowest. In this state, the discharge amount of the molding material per unit time from the nozzle 61 is maximized. In this way, the opening/closing mechanism 70 can switch between opening and closing of the ejection of the modeling material, and can adjust the ejection amount of the modeling material.

Fig. 5 is a flowchart showing the content of the modeling process in the present embodiment. This processing is executed by the control unit 500 when a predetermined start operation is performed by the user on an operation panel provided in the three-dimensional modeling apparatus 100 or on a computer connected to the three-dimensional modeling apparatus 100.

First, in step S110, the control unit 500 acquires modeling data for modeling the three-dimensional modeled object. The modeling data is data indicating information on a movement path of the nozzle surface 63 with respect to the modeling surface 310 of the stage 300, a target position at which the modeling material is discharged from the nozzle hole 62 to the modeling surface 310, a discharge amount of the modeling material discharged from the nozzle hole 62, and the like. The modeling data is created, for example, by microtome software installed in a computer connected to the three-dimensional modeling apparatus 100. The microtome software reads shape data indicating the shape of the three-dimensional shaped object created by the three-dimensional CAD software or the three-dimensional CG software, and creates shape data for each layer by dividing the shape of the three-dimensional shaped object into layers having a predetermined thickness. In the shape data read into the microtome software, data such as STL format or AMF format may be used. The model data created by the microtome software is represented by a G code, an M code, or the like. The control unit 500 acquires modeling data from a computer connected to the three-dimensional modeling apparatus 100, or from a storage medium such as a USB memory.

Next, in step S120, the control unit 500 starts the molding material generation. The control unit 500 controls the rotation of the flat screw 40 and the temperature of the heating unit 58, thereby plasticizing the material MR and producing the molding material. Further, the molding material is continuously produced during the execution of the treatment.

Fig. 6 is an explanatory diagram schematically showing a state where the three-dimensional object OB is molded. Fig. 7 is a sectional view taken along line VII-VII in fig. 6. Referring to fig. 5 to 7, in step S130, the control section 500 controls the moving section 400 to eject the modeling material from the nozzle hole 62 toward the target position of the modeling surface 310 while changing the relative position between the nozzle surface 63 and the modeling surface 310, thereby modeling the first layer LY1 of the three-dimensional modeled object OB on the modeling surface 310. Thereafter, in step S140, the control unit 500 determines whether or not the shaping of all layers of the three-dimensional shaped object OB is completed. The control unit 500 can determine whether or not the molding of all layers of the three-dimensional object OB is completed using the molding data. When it is not judged in step S140 that the modeling of all the layers of the three-dimensional shaped object OB is completed, the control section 500 returns the process to step S130, and models the second layer LY2 on the first layer LY1 by ejecting the modeling material from the nozzle hole 62 toward the first layer LY 1. On the other hand, when it is determined in step S140 that the modeling of all the layers of the three-dimensional shaped object OB is completed, the control unit 500 ends the processing. The control unit 500 repeats the process of step S130 to stack the layers of the molding material, thereby molding the three-dimensional object OB until it is determined in step S140 that molding of all the layers of the three-dimensional object OB is completed.

In the present embodiment, the control unit 500 drives the moving unit 400 so that the relationship between the gap G and the outer diameter Dp of the nozzle surface 63 satisfies the following expression (1), the relationship between the gap G and the inner diameter Dh of the nozzle hole 62 satisfies the following expression (2), and the gap G satisfies the following expression (3) during the shaping process.

Dp≤20×G+0.20[mm]…(1)

0＜G≤Dh…(2)

0.05[mm]≤G≤0.20[mm]…(3)

The interval G indicates an interval between the molding surface 310 or the molding material layer and the nozzle surface 63 when the molding material is discharged from the nozzle hole 62. In the case of shaping the first layer LY1, the spacing G represents the spacing between the shaping surface 310 and the nozzle surface 63 in a direction perpendicular to the shaping surface 310. In the case of shaping the n-th layer LYn, the interval G indicates the interval between the upper surface of the n-1 st layer LYn-1 and the nozzle face 63 in the direction perpendicular to the shaping face 310. Here, n is a natural number of 2 or more. For example, in the case of shaping the second layer LY2, the interval G indicates the interval between the upper surface of the first layer LY1 and the nozzle face 63. In the present embodiment, the control unit 500 drives the moving unit 400 so that the gap G is maintained at 0.05 mm. The information on the movement path of the nozzle surface 63 with respect to the molding surface 310, which is expressed in the molding data, includes information on the interval G, and the control unit 500 drives the moving unit 400 based on the molding data. Information on the outer diameter Dp of the nozzle face 63 and the inner diameter Dh of the nozzle hole 62 is input by the user when creating the modeling data. The control unit 500 controls the discharge amount so that the line width W of the molding material is maintained at 0.30 mm. In the present embodiment, as described above, the inner diameter Dh of the nozzle hole 62 is 0.20mm, and the outer diameter Dp of the nozzle surface 63 is 0.50 mm. Therefore, the outer diameter Dp of the nozzle surface 63 satisfies the following expression (4).

0.50[mm]≤Dp≤2.20[mm]…(4)

Fig. 8 is a table showing test results for examining the quality of the dimensional accuracy of the three-dimensional object OB. Fig. 8 shows, in order from the left, how good the inner diameter Dh of the nozzle hole 62, the outer diameter Dp of the nozzle surface 63, the gap G, the line width W, the surface roughness Rz, and the dimensional accuracy are. In this test, samples S1 to S15 of 15 kinds of three-dimensionally shaped objects OB were shaped using the three-dimensional shaping apparatus 100 so that the combinations of the outer diameter Dp and the interval G of the nozzle surface 63 were different, and the quality of the dimensional accuracy of each of the samples S1 to S15 was examined. Each of the samples S1 to S15 was molded into a cubic shape having a side length of 10mm as a target shape. In the materials of the respective samples S1 to S15, granular ABS resin was used. The modeling material was discharged onto the upper surface of the layer of modeling material while the temperature of the upper surface of the layer of modeling material was maintained at 105 degrees celsius, and the samples S1 to S15 were modeled. The surface roughness Rz is measured by a method described in JIS B0601: 2013, as specified by the maximum height. The surface roughness Rz is a value obtained by measuring the side surface portions of the cubic samples S1 to S15 with an optical coherence type three-dimensional measuring instrument. For the three-dimensional measuring instrument, VR-3000 manufactured by Keyence corporation was used. Regarding the quality of the dimensional accuracy, when no significant shape collapse visually recognizable with naked eyes was found in each of samples S1 to S15, the character "OK" was indicated as the case of good dimensional accuracy, and when significant shape collapse visually recognizable with naked eyes was found in each of samples S1 to S15, the character "NG" was indicated as the case of poor dimensional accuracy.

Fig. 9 is an image showing the appearance of sample S1. Fig. 10 is an image showing the appearance of sample S10. Fig. 11 is an image showing the appearance of sample S12. As shown in fig. 9 and 10, the samples S1 and S10 had smooth surfaces, and no significant shape collapse was visually recognized by the naked eye on the samples S1 and S10. As shown in fig. 11, the sample S12 had a rough surface like fuzz, and there was a distinct shape collapse on the sample S12 that could be visually confirmed with the naked eye. As a result of this test, no distinct shape collapse was observed in samples S1 to S11, which could be visually observed with the naked eye. On the other hand, samples S12 to S15 showed a visually recognizable shape collapse. That is, the dimensional accuracy of the samples S1 to S11 was good, but the dimensional accuracy of the samples S12 to S15 was not good. In addition, for samples S1 to S3, the measurement of the surface roughness Rz was omitted. Samples S12 to S15 had a significant shape collapse, and thus the surface roughness Rz could not be measured.

Fig. 12 is a graph showing the test results of examining the quality of dimensional accuracy of a three-dimensional shaped object. The horizontal axis represents the outer diameter Dp of the nozzle surface 63. The vertical axis represents the interval G. Fig. 12 shows the relationship between the outer diameter Dp of the nozzle surface 63 and the gap G when the samples S1 to S15 were molded. In fig. 12, samples S1 to S11 that showed good dimensional accuracy are indicated by "o" marks, and samples S12 to S15 that showed poor dimensional accuracy are indicated by "x" marks. A region on the upper side of the straight line LN with respect to the line including the straight line LN in fig. 12 is a region in which the relationship between the gap G and the outer diameter Dp of the nozzle surface 63 satisfies the above expression (1). When the relationship between the interval G and the outer diameter Dp of the nozzle surface 63 satisfies the above expression (1), the three-dimensional object OB can be molded with high dimensional accuracy.

Fig. 13 is an explanatory diagram schematically showing a case where the nozzle 61 interferes with the three-dimensional object OB during modeling. The nozzle 61 is provided such that the nozzle surface 63 is parallel to the modeling surface 310 of the stage 300. However, the inclination θ is inevitably generated between the nozzle surface 63 and the modeling surface 310 due to the machining accuracy when machining the nozzle surface 63, the assembly accuracy when assembling the nozzle 61, and the like. Therefore, when the relationship between the interval G and the outer diameter Dp of the nozzle face 63 becomes such that it does not satisfy the above expression (1), the nozzle face 63 and the n-1 st layer LYn-1 may interfere with each other or the nozzle face 63 and a part of the n-th layer LYn that has already been molded may interfere with each other when the n-th layer LYn of the three-dimensional molded object OB is molded. For example, when the nozzle surface 63 interferes with the n-1 st layer LYn-1, the molding material constituting the n-1 st layer LYn-1 may be pushed outward as indicated by an arrow in fig. 13, thereby roughening the surface of the three-dimensional object OB.

According to the three-dimensional modeling apparatus 100 of the present embodiment described above, since the control unit 500 drives the moving unit 400 so that the relationship between the distance G and the outer diameter Dp of the nozzle surface 63 satisfies the above expression (1), it is possible to suppress interference between the nozzle surface 63 and the three-dimensional object OB being modeled. Therefore, the surface of the three-dimensional object OB can be prevented from being roughened.

In the present embodiment, since the control unit 500 drives the moving unit 400 so that the relationship between the inner diameter Dh and the interval G of the nozzle hole 62 satisfies the above expression (2), the modeling material discharged between the modeling surface 310 and the nozzle surface 63 or between the layer of the modeling material and the nozzle surface 63 can be modeled while being crushed by the nozzle surface 63. Therefore, the thickness of the layer of the modeling material can be reduced, and therefore, the three-dimensional object OB having a smooth surface can be modeled.

In the present embodiment, the control unit 500 drives the moving unit 400 so that the interval G satisfies the above expression (3), and thus the three-dimensional object OB having a smooth surface can be shaped.

In the present embodiment, since the nozzle 61 is configured such that the outer diameter Dp of the nozzle surface 63 satisfies the above expression (4), the gap G can be prevented from being reduced even when the nozzle surface 63 is inclined with respect to the molding surface 310. Therefore, the possibility of the nozzle 61 interfering with the three-dimensional object OB during molding can be reduced.

In the present embodiment, the ABS resin in the form of particles is used as the material MR, but as the material MR used in the modeling unit 200, for example, a material that models a three-dimensional modeled object using various materials such as a thermoplastic material, a metal material, and a ceramic material as main materials can be used. Here, the term "main material" means a material that forms the center of the shape of the three-dimensional shaped object, and means a material that occupies a content of 50% by weight or more in the three-dimensional shaped object. The molding material described above includes a material obtained by melting these main materials in a single body form, or a material obtained by melting a part of components contained together with the main materials to form a paste.

When a material having thermal plasticity is used as the main material, the plasticizing unit 30 plasticizes the material to produce a molding material. "plasticization" means melting a thermoplastic material by applying heat thereto. The term "melt" also means that a material having thermal plasticity is softened by heating to a temperature equal to or higher than the glass transition point, thereby exhibiting fluidity.

As the material having the thermoplastic property, for example, a thermoplastic resin material obtained by combining any one or two or more of the following materials can be used.

Examples of thermoplastic resin materials

Examples of the engineering plastic include general engineering plastics such as polypropylene resin (PP), polyethylene resin (PE), polyoxymethylene resin (POM), polyvinyl chloride resin (PVC), polyamide resin (PA), acrylonitrile-butadiene-styrene polymer resin (ABS), polylactic acid resin (PLA), polyphenylene sulfide resin (PPs), Polycarbonate (PC), modified polyphenylene ether, polybutylene terephthalate, and polyester synthetic fiber, and engineering plastics such as polysulfone, polyethersulfone, polyphenylene sulfide, polyarylate, polyimide, polyamide-imide, polyetherimide, and polyether ether ketone (PEEK).

The thermoplastic material may contain additives such as wax, flame retardant, antioxidant, and heat stabilizer in addition to pigments, metals, and ceramics. The material having thermal plasticity is plasticized and converted into a molten state by the rotation of the flat screw 40 and the heating of the heating portion 58 in the plasticizing portion 30. Further, the modeling material produced in this way is solidified by lowering the temperature after being ejected from the nozzle hole 62.

Preferably, the thermoplastic material is ejected from the nozzle hole 62 in a state of being heated to a glass transition point or higher and completely melted. The term "completely melted state" means a state in which no unmelted thermoplastic material is present, and for example, when a granular thermoplastic resin is used as a material, it means a state in which no granular solid matter remains.

In the molding unit 200, instead of the material having the thermoplastic property described above, for example, the following metal material may be used as a main material. In this case, it is preferable that a component melted at the time of producing the molding material is mixed with a powder material obtained by powdering a metal material described below, and the mixture is charged into the plasticizing unit 30.

Examples of the metallic Material

Magnesium (Mg), iron (Fe), cobalt (Co), chromium (Cr), aluminum (Al), titanium (Ti), copper (Cu), nickel (Ni), or an alloy containing one or more of these metals.

Examples of alloys

Maraging steel, stainless steel, cobalt-chromium-molybdenum alloy, titanium alloy, nickel alloy, aluminum alloy, cobalt alloy, and cobalt-chromium alloy.

In the molding unit 200, instead of the metal material, a ceramic material may be used as a main material. As the ceramic material, for example, an oxide ceramic such as silica, titania, alumina, or zirconia, a non-oxide ceramic such as aluminum nitride, or the like can be used. In the case where a metal material or a ceramic material as described above is used as a main material, the modeling material disposed on the stage 300 may be cured by, for example, irradiation with a laser beam or sintering using hot air.

The powder material of the metal material or the ceramic material to be charged into the material supply portion 20 may be a mixed material obtained by mixing a single metal powder, an alloy powder, or a powder of a ceramic material in plural kinds. The powder material of the metal material or the ceramic material may be coated with the thermoplastic resin exemplified above or another thermoplastic resin. In this case, the thermoplastic resin may be melted in the plasticizing part 30 to exhibit fluidity.

The following solvent may be added to the powder material of the metal material or the ceramic material charged into the material supply unit 20, for example. The solvent may be one or a combination of two or more selected from the following solvents.

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; acetates such as acetate, 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 methyl sulfoxide and diethyl sulfoxide; pyridine solvents such as pyridine, γ -picoline and 2, 6-lutidine; tetraalkylammonium acetates (e.g., tetrabutylammonium acetate, etc.); ionic liquids such as butyl carbitol acetate, and the like.

In addition, a binder described below, for example, may be added to the powder material of the metal material or the ceramic material charged into the material supply unit 20.

Examples of Adhesives

Acrylic, epoxy, silicone, cellulose-based or other synthetic resins or PLA (polylactic acid), PA (polyamide), PPS (polyphenylene sulfide), PEEK (polyether ether ketone), or other thermoplastic resins.

B. Other embodiments are as follows:

(B1) in the three-dimensional modeling apparatus 100 of the first embodiment, the control unit 500 drives the moving unit 400 so that the relationship between the gap G and the inner diameter Dh of the nozzle hole 62 satisfies the above expression (2). On the other hand, the control unit 500 may not drive the moving unit 400 so as to satisfy the expression (2).

(B2) In the three-dimensional modeling apparatus 100 according to the first embodiment, the control unit 500 drives the moving unit 400 such that the interval G satisfies the above-described expression (3). On the other hand, the controller 500 may not drive the moving unit 400 so as to satisfy the expression (3).

(B3) In the three-dimensional modeling apparatus 100 of the first embodiment, the nozzle 61 is configured such that the outer diameter Dp of the nozzle surface 63 satisfies the above equation (4). In contrast, the nozzle 61 may not be configured so that the outer diameter Dp of the nozzle surface 63 satisfies the formula (4).

(B4) The three-dimensional modeling apparatus 100 according to the first embodiment described above may include a plurality of modeling units 200. For example, the three-dimensional modeling apparatus 100 may be configured to include two modeling units 200, and to discharge the modeling material from the nozzle hole 62 of one modeling unit 200 and to discharge the support material for holding the shape of the three-dimensional modeled object OB during modeling from the nozzle hole 62 of the other modeling unit 200. In this case, the control unit 500 changes the relative position between the nozzle surface 63 and the modeling surface 310 of each modeling unit 200 by the moving unit 400. The control unit 500 drives the moving unit 400 so that the relationship between the distance G between the molding surface 310 or the layer of the molding material or the layer of the support material and the nozzle surface 63 and the outer diameter Dp of the nozzle surface 63 when the molding material or the support material is discharged from the nozzle holes 62 of the respective molding units 200 satisfies the above-described expression (1). The inner diameter Dh of the nozzle hole 62, the outer diameter Dp of the nozzle face 63, and the interval G may be different for each molding unit 200.

(B5) In the three-dimensional modeling apparatus 100 according to the first embodiment, the plasticizing unit 30 includes the flat cylindrical screw 40 and the cylinder 50 having the flat screw 52 facing each other. In contrast, the plasticizing unit 30 may include a screw having a spiral groove formed in a side surface of the elongated shaft member, and a cylinder having a cylindrical screw facing surface facing the groove. The three-dimensional modeling apparatus 100 may be an FDM method (thermal fusion lamination method) instead of the method of plasticizing the material by the rotation of the flat screw 40.

C. Other modes are as follows:

the present disclosure is not limited to the above-described embodiments, and can be implemented in various ways without departing from the scope of the present disclosure. For example, the present disclosure may also be implemented in the following manner. Technical features in the above-described embodiments that correspond to technical features in the respective embodiments described below can be appropriately replaced or combined in order to solve part or all of the problems of the present disclosure or to achieve part or all of the effects of the present disclosure. Note that, if this technical feature is not described as an essential feature in the present specification, it can be appropriately deleted.

(1) According to one embodiment of the present disclosure, there is provided a three-dimensional modeling apparatus for modeling a three-dimensional modeled object by laminating material layers. The three-dimensional modeling apparatus includes: an object stage; an ejection section having a nozzle surface on which a nozzle hole is formed; a moving unit that changes a relative position between the stage and the nozzle surface; and a control unit that controls the moving unit. The control unit drives the moving unit such that a relationship between a distance G between the stage or the material layer and the nozzle surface when the material is ejected from the ejection unit and an outer diameter Dp of the nozzle surface satisfies the following expression (1).

Dp≤20×G+0.20[mm]…(1)

According to the three-dimensional modeling apparatus of this aspect, it is possible to suppress the nozzle from interfering with the three-dimensional object being modeled and to roughen the surface of the three-dimensional object.

(2) In the three-dimensional modeling apparatus of the above aspect, the control unit may drive the moving unit such that a relationship between the inner diameter Dh of the nozzle hole and the gap G satisfies the following expression (2).

0＜G≤Dh…(2)

According to the three-dimensional modeling apparatus of this aspect, since the material ejected between the stage and the nozzle surface or between the material layer and the nozzle surface can be modeled while being crushed by the nozzle surface, it is possible to model a three-dimensional modeled object having a smooth surface.

(3) In the three-dimensional modeling apparatus according to the above aspect, the control unit may drive the moving unit such that the interval G satisfies the following expression (3).

0.05[mm]≤G≤0.20[mm]…(3)

According to the three-dimensional modeling apparatus of this aspect, a three-dimensional modeled object having a smooth surface can be modeled.

(4) In the three-dimensional modeling apparatus of the above aspect, the discharge portion may be configured such that an outer diameter Dp of the nozzle surface satisfies the following expression (4).

0.50[mm]≤Dp≤2.20[mm]…(4)

According to the three-dimensional modeling apparatus of this aspect, even when the nozzle surface is inclined with respect to the stage, it is possible to suppress interference between the nozzle and the three-dimensional object being modeled.

The present disclosure can be implemented in various ways other than the three-dimensional modeling apparatus. For example, the present invention can be realized by a control method of a three-dimensional modeling apparatus, a modeling method of a three-dimensional modeled object, and the like.

Description of the symbols

20 … material supply; 22 … supply channel; 30 … plasticizing part; 31 … helix shell; 32 … drive motor; 40 … flat spiral; 41 … upper surface; 42 … groove forming faces; 43 … side; 44 … material introduction port; 45 … groove portions; 46 … raised strips; 47 … center; 50 … barrel; 52 … opposite sides of the spiral; 54 … guide slot; 56 … pass through the holes; 58 … heating section; 60 … discharge part; a 61 … nozzle; 62 … nozzle hole; 63 … nozzle face; 65 … flow path; 70 … opening and closing mechanism; 72 … drive shaft; 73 … a valve body; a 74 … valve drive; 100 … three-dimensional modeling apparatus; 200 … molding units; a 300 … stage; 310 … molding surface; 400 … moving part; 500 … control section.