Filament manufacturing equipment, filament manufacturing method, filament, three-dimensional structure manufacturing equipment, three-dimensional structure

Abstract

To continuously change physical properties of a three-dimensional structure.SOLUTION: A filament 5 has a continuously varying mixing ratio of two or more resins along its longitudinal direction. A difference between a maximum line width and a minimum line width of the filament 5 is 0.1 mm or less.SELECTED DRAWING: Figure 2

Description

Technical Field

[0005] , ,

[0001] The present disclosure relates to a filament manufacturing apparatus, a method for manufacturing a filament, a filament, a three-dimensional structure manufacturing apparatus using the filament, and a three-dimensional structure manufactured using the filament.

Background Art

[0002] As an apparatus for manufacturing a three-dimensional structure, a so-called 3D printer is known. By using a 3D printer, a three-dimensional structure having a complex shape can be easily manufactured. The 3D printer manufactures a three-dimensional structure by melting and stacking a linear filament made of, for example, resin.

[0003] The physical properties of the manufactured three-dimensional structure depend on the physical properties of the filament. In order to improve the physical properties of the three-dimensional structure, adjusting the physical properties of the filament has been studied. For example, in Non-Patent Document 1, a method of changing the hardness of the resin forming the filament in the manufacturing process of the filament has been studied.

Prior Art Documents

Non-Patent Documents

[0004]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] If the physical properties of the filament, such as the hardness of the resin that makes up the filament, change, it may not be possible to properly manufacture a three-dimensional structure using that filament. The inventors of this invention have found that, in order to properly manufacture a three-dimensional structure using a filament, it is important that the filament's line width remains approximately constant. However, it is difficult to maintain a nearly constant line width for a filament whose physical properties are continuously changing.

[0006] The present disclosure aims to provide a filament that enables continuous changes in the physical properties of a three-dimensional structure manufactured using a three-dimensional structure manufacturing apparatus. [Means for solving the problem]

[0007] One embodiment of the present disclosure relates to the following [1] to

[14] . [1] A twin-screw extruder that melts and mixes two or more different resin materials and continuously extrudes filaments from an extrusion port, A cooling fan for cooling the filament extruded from the extrusion port, A spool for winding the aforementioned filament, A filament manufacturing apparatus comprising a filament winder that adjusts the speed at which the spool winds the filament. [2] The filament manufacturing apparatus according to [1], wherein the cooling fan is positioned vertically below the filament. [3] The filament manufacturing apparatus according to [1] or [2], wherein the rotational speed of the cooling fan is 2500 rpm or more and 3000 rpm or less. [4] In the vertical direction, the position where the spool winds the filament is higher than the extrusion port, according to any one of [1] to [3]. [5] The method for manufacturing a filament according to any one of [1] to [4], wherein the speed at which the spool winds the filament is 3 m / min or more and 5 m / min or less. [6] A method for manufacturing a filament using a filament manufacturing apparatus described in any of [1] to [5], A method for manufacturing a filament, comprising the step of extruding the filament while continuously changing the ratio of two or more different resin materials that are melted and mixed by the twin-screw extruder. [7] The spool includes the step of winding the filament, The method for manufacturing a filament according to [6], wherein the speed at which the spool winds the filament is adjusted by the filament winder to a speed corresponding to the speed at which the twin-screw extruder pushes out the filament. [8] A filament in which the mixing ratio of two or more resins changes continuously along the longitudinal direction, A filament in which the difference between the maximum and minimum line width is 0.1 mm or less. [9] The filament according to [8], wherein the two or more resins include a thermoplastic elastomer and a polyolefin.

[10] The filament according to [9], wherein the proportion of the thermoplastic elastomer at any position in the longitudinal direction of the filament is 80% by mass or less.

[11] A manufacturing apparatus for a three-dimensional structure using a filament described in any of [8] to

[10] , A stand that supports the spool on which the filament is wound, A manufacturing apparatus for three-dimensional structures, comprising a nozzle for extruding the aforementioned filament.

[12] The inside of the nozzle is coated with Teflon, as described in

[11] , for the manufacturing apparatus of a three-dimensional structure.

[13] The apparatus for manufacturing a three-dimensional structure according to

[11] or

[12] , wherein the stand is rotatable and movable in a direction toward and away from the nozzle.

[14] A three-dimensional structure manufactured using the filaments described in [8] to

[10] , where the mixing ratio of two or more resins contained in the three-dimensional structure continuously changes along the first direction.

Advantages of the Invention

[0008] According to the present disclosure, the physical properties of the three-dimensional structure can be continuously changed.

Brief Description of the Drawings

[0009] [Figure 1] FIG. 1 is a perspective view showing an example of a three-dimensional structure. [Figure 2] FIG. 2 is a front view showing an example of a filament. [Figure 3] FIG. 3 is a perspective view showing a spool around which a filament is wound. [Figure 4] FIG. 4 is a front view schematically showing a filament manufacturing apparatus. [Figure 5] FIG. 5 is a cross-sectional view showing the inside of a twin-screw extruder. [Figure 6] FIG. 6 is a front view of a manufacturing apparatus for a three-dimensional structure. [Figure 7] FIG. 7 is a perspective view showing a stand that supports a spool around which a filament is wound. [Figure 8] FIG. 8 is a front view showing an example of a manufacturing process for a three-dimensional structure. [Figure 9] FIG. 9 is a perspective view showing a three-dimensional structure used in a cantilever test. [Figure 10] FIG. 10 is a diagram for explaining the process of a cantilever beam bending test. [Figure 11] FIG. 11 is a diagram for explaining the process of a cantilever beam bending test. [Figure 12] FIG. 12 is a graph showing the results of a cantilever beam bending test.

Modes for Carrying Out the Invention

[0010] Hereinafter, an embodiment of this disclosure will be described with reference to the drawings. The scale and aspect ratios of the dimensions in the drawings attached to this specification have been altered and exaggerated from those of the actual objects for illustrative purposes and ease of understanding.

[0011] In this specification, terms such as "parallel," "orthogonal," and "identical," as well as values ​​of length and angle, which specify shapes, geometric conditions, and their degrees, are to be interpreted not in a strict sense, but to include a range that can be expected to function similarly.

[0012] Figure 1 shows an example of a three-dimensional structure according to one embodiment of the present disclosure. The three-dimensional structure 1 shown in Figure 1 is a so-called cup. More specifically, the three-dimensional structure 1 shown in Figure 1 is cylindrical in shape extending in a first direction d1, and has a bottom and an opening facing each other in the first direction d1. The three-dimensional structure 1 is not limited to the example shown in Figure 1, but may have any shape. The physical properties of the three-dimensional structure 1 shown in Figure 1 change continuously along the first direction d1. Specifically, the hardness of the three-dimensional structure 1 shown in Figure 1 changes continuously along the first direction d1. More specifically, the three-dimensional structure 1 shown in Figure 1 becomes softer from the bottom towards the opening. The three-dimensional structure 1 shown in Figure 1 can contain liquid. Because the area near the bottom is hard, the three-dimensional structure 1 can stably contain liquid. Because the area near the opening is soft, the area near the opening can be deformed. By deforming the area near the opening to an appropriate shape, the liquid contained within the three-dimensional structure 1 can be easily poured out. The three-dimensional structure 1 combines strength and flexibility. Furthermore, the three-dimensional structure 1 shown in Figure 1 has a continuous change in color from the bottom towards the opening along the first direction d1. The three-dimensional structure 1 is given an excellent gradient design. The hardness of the three-dimensional structure 1 can be visually perceived through its color.

[0013] Three-dimensional structure 1 is manufactured by layering resins. Three-dimensional structure 1 contains two or more types of resins. In three-dimensional structure 1 shown in Figure 1, the mixing ratio of the two or more types of resins changes continuously along the first direction d1 so that the physical properties change continuously along the first direction d1, specifically so that it becomes softer and the color changes continuously along the first direction d1. Because the mixing ratio of the resins changes continuously, delamination due to differences in the mixing ratio of the resins is less likely to occur in three-dimensional structure 1.

[0014] The three-dimensional structure 1 shown in Figure 1 can be manufactured using a filament 5 as shown in Figure 2. The filament 5 is a linear molded body containing two or more types of resin. In the filament 5 shown in Figure 2, the mixing ratio of the two or more types of resin changes continuously along the longitudinal direction dL. Because the mixing ratio of the resins changes continuously, delamination due to differences in the mixing ratio of the resins is less likely to occur in the filament 5. Due to the continuous change in the mixing ratio of the resins, the physical properties of the filament 5 change continuously along the longitudinal direction dL. For example, the hardness and color of the filament 5 change continuously along the longitudinal direction dL. The hardness of the filament 5 can be visually perceived by its color. The line width of the filament 5 is, for example, 1.7 mm or more and 1.8 mm or less. The line width of the filament 5 is approximately constant. Specifically, the difference between the maximum line width and the minimum line width of the filament 5 is, for example, 0.1 mm or less, preferably 0.05 mm or less. The line width of filament 5 is the length of filament 5 in the direction perpendicular to the longitudinal direction dL of filament 5.

[0015] It is preferable that the three-dimensional structure 1 and the filament 5 are composed of two or more resins with different viscoelastic properties. If the filament 5 is composed of two or more resins with different viscoelastic properties, and the three-dimensional structure 1 is manufactured using filament 5 with varying proportions of these resins, then a three-dimensional structure 1 with continuously changing hardness as described above can be obtained. The two or more resins with different viscoelastic properties are, for example, a combination of a thermoplastic elastomer and a thermoplastic resin.

[0016] Thermoplastic elastomers are copolymers containing, for example, structural units derived from α-olefins and structural units derived from other olefins different from the α-olefin. The α-olefin may typically contain one type of α-olefin having 2 to 20 carbon atoms, or two or more types in combination. Preferred α-olefins are those having 3 or more carbon atoms, with α-olefins having 3 to 8 carbon atoms being particularly preferred. Copolymers containing structural units derived from α-olefins having 2 to 8 carbon atoms and structural units derived from olefins having 2 to 3 carbon atoms are preferred because they have excellent compatibility with thermoplastic resins (especially polypropylene), which will be described later, making them less prone to delamination when used in three-dimensional structures.

[0017] Thermoplastic resins include general-purpose plastics such as high-density polyethylene (HDPE), low-density polyethylene (LDPE), polypropylene polymers (propylene homopolymer (PP), etc.), polyvinyl chloride (PVC), polyvinylidene chloride, polystyrene (PS), polyvinyl acetate (PVAc), polytetrafluoroethylene (PTFE), acrylonitrile butadiene styrene resin (ABS resin), styrene acrylonitrile copolymer (AS resin), and acrylic resin (PMMA); polyamide (PA), polyacetal (POM), polycarbonate (PC), modified polyphenylene ether (m-PPE, modified PPE, PPO), polybutylene terephthalate (PBT), polyethylene terephthalate Engineering plastics such as refractate (PET), syndiotactic polystyrene (SPS), and cyclic polyolefin (COP); super engineering plastics such as polyphenylene sulfide (PPS), polytetrafluoroethylene (PTFE), polysulfone (PSF), polyethersulfone (PES), amorphous polyarylate (PAR), polyetheretherketone (PEEK), thermoplastic polyimide (PI), and polyamideimide (PAI); preferably polyolefins such as polyethylene or polypropylene polymers, and in particular, when using the above-mentioned thermoplastic elastomers, it is preferable to use polypropylene polymers in combination. The propylene polymer may be a homopolymer of propylene or a copolymer of propylene and another monomer.

[0018] In addition to the resin described above, the three-dimensional structure 1 and filament 5 may also contain additives such as ultraviolet absorbers, stabilizers, antioxidants, plasticizers, colorants, color adjusters, flame retardants, antistatic agents, fluorescent whitening agents, matting agents, and impact strength modifiers.

[0019] The proportion of thermoplastic elastomer is not excessive so that the filament 5 and the three-dimensional structure 1 can be properly manufactured using the filament 5. At any position along the longitudinal direction dL of the filament, the proportion of thermoplastic elastomer is, for example, 80% by mass or less, depending on the type of thermoplastic elastomer used. In other words, no matter which part is taken from the filament 5, the proportion of thermoplastic elastomer contained in the filament 5 is, for example, 80% by mass or less. At any position in the three-dimensional structure 1 manufactured using the filament 5, the proportion of thermoplastic elastomer is, for example, 80% by mass or less. In other words, no matter which part is taken from the three-dimensional structure 1, the proportion of thermoplastic elastomer contained in the three-dimensional structure 1 is, for example, 80% by mass or less.

[0020] The proportion of thermoplastic elastomer can be appropriately changed depending on the type of thermoplastic elastomer used. The type of thermoplastic elastomer used can be appropriately selected depending on the type of thermoplastic resin used.

[0021] Figure 3 shows a spool 40 on which the filament 5 is wound. Because the filament 5 is wound on the spool 40, it can be easily handled.

[0022] A filament manufacturing apparatus 10 for producing filament 5 wound onto a spool 40 will be described. Figure 4 shows a schematic representation of the filament manufacturing apparatus 10. In the example shown in Figure 4, the filament manufacturing apparatus 10 includes a twin-screw extruder 20, a cooling fan 30, a spool 40, and a filament winder 50.

[0023] The twin-screw extruder 20 melts and mixes two or more resin materials and continuously extrudes them. The extruded resin becomes the filament 5. Figure 5 shows the inside of the twin-screw extruder 20. As shown in Figures 4 and 5, the twin-screw extruder 20 has an inlet 21, a cylinder 22, two screws 23, and an extrusion port 24. The inlet 21 is the entrance into which pellets of the resin composition that will become the material for the filament 5 extruded by the twin-screw extruder 20 are fed. Two or more resin materials can be fed into the inlet 21 while continuously changing their proportions. The inlet 21 leads to the cylinder 22. The cylinder 22 is cylindrical in shape, and the resin composition fed in from the inlet 21 enters its interior. The cylinder 22 is provided with a heating means, such as an electric heating wire (not shown). The heating means heats the inside of the cylinder 22 and melts the resin composition. The heating means heats the inside of the cylinder 22 to, for example, 150°C to 200°C. The screw 23 rotates, advancing the molten resin composition inside the cylinder 22 toward the extrusion port 24. Two screws 23 are located inside the cylinder 22. The rotation of the two screws 23 allows for the proper mixing of different types of resin materials. The screws 23 are rotationally driven by a drive unit (not shown). By controlling the rotational speed of the screws 23, the speed at which the twin-screw extruder 20 extrudes the filaments 5 can be controlled. The extrusion port 24 is located at the tip of the cylinder 22. The mixed resin is continuously extruded from the extrusion port 24 as linear filaments 5. The line width of the extruded filaments 5 depends on the inner diameter of the extrusion port 24. The inner diameter of the extrusion port 24 is, for example, 1.7 mm or more and 1.8 mm or less.

[0024] The cooling fan 30 cools the filament 5 extruded from the extrusion port 24 of the twin-screw extruder 20 by blowing air onto it. Cooling by blowing air onto the filament suppresses deterioration of the filament 5 due to moisture compared to cooling the filament by immersing it in water. The cooling fan 30 is positioned near the extrusion port 24 of the twin-screw extruder 20, along the direction of travel of the filament 5, so that it can quickly cool the filament 5 extruded from the extrusion port 24 of the twin-screw extruder 20. The cooling fan 30 is positioned along the filament 5 for a sufficient length so that the filament 5 can be sufficiently cooled. The length over which the cooling fan 30 is positioned is, for example, 300 mm to 500 mm. Multiple cooling fans 30 may be positioned to cover a sufficient length. In the example shown in Figure 4, four cooling fans 30 are positioned. The cooling fan 30 is positioned vertically below the filament 5. The cooling fan 30 blows air onto the filament 5 from vertically below. The cooling fan 30 blows air by rotating. The rotational speed of the cooling fan 30 is, for example, between 2500 rpm and 3000 rpm.

[0025] The spool 40 winds up the filament 5 that has been cooled by the cooling fan 30. The spool 40 is a disc-shaped winding cylinder that can wind up the filament 5 while it is circulating. By rotating the spool 40 in one direction, the filament 5 can be wound up along the circumference of the spool 40. The position where the spool 40 winds up the filament 5 is higher than the extrusion port 24 of the twin-screw extruder 20 in the vertical direction. The position where the spool 40 winds up the filament 5 means the position where the filament 5 being wound up comes into contact with the spool 40 or the filament 5 wound on the spool 40.

[0026] The filament winder 50 adjusts the speed at which the spool 40 winds the filament 5 by adjusting the rotational speed of the spool 40. The filament winder 50 adjusts the speed at which the spool 40 winds the filament 5 to correspond to the speed at which the twin-screw extruder 20 pushes out the filament 5. More specifically, the filament winder 50 adjusts the speed at which the spool 40 winds the filament 5 to be equal to the speed at which the twin-screw extruder 20 pushes out the filament 5. By adjusting the filament winder 50, the speed at which the spool 40 winds the filament 5 can be set to, for example, between 3 m / min and 5 m / min.

[0027] An example of a method for manufacturing a filament using the filament manufacturing apparatus 10 described above will now be explained. The method for manufacturing a filament includes the steps of introducing a resin composition to be used as a resin material, melting and mixing the resin material and extruding it, cooling the filament 5, and having the spool 40 wind up the filament 5.

[0028] A resin composition, which will become the resin material, is fed into the inlet 21 of the twin-screw extruder 20. The resin composition is in the form of pellets. Two or more different resin materials are fed into the inlet 21. For example, polyolefin pellets and thermoplastic elastomer pellets are fed in. The proportion of the different resin materials fed in is continuously changed as the filament 5 is produced. The proportion of the different resin materials fed in may be changed manually while visually checking, or it may be changed automatically using a device.

[0029] The introduced resin material is melted, mixed, and extruded. The resin composition introduced into the input port 21 enters the cylinder 22 of the twin-screw extruder 20. Inside the cylinder 22, the resin composition is melted by heat and mixed by two screws 23, and then moved towards the extrusion port 24. As the proportions of the different materials introduced change continuously, the proportions of the different materials that the twin-screw extruder 20 melts and mixes also change continuously. At the extrusion port 24, a filament 5 is extruded that extends continuously in a linear fashion with a line width dependent on the inner diameter of the extrusion port 24.

[0030] The filament 5 extruded from the extrusion port 24 is cooled by a cooling fan 30. The cooling fan 30 cools the filament 5 by blowing air from below it. The cooling fan 30 rotates at a speed of, for example, 2500 rpm to 3000 rpm. The cooling fan 30 is positioned at an appropriate length along the filament 5. Proper cooling suppresses the elongation of the filament 5, keeping the line width of the filament 5 approximately constant.

[0031] The cooled filament 5 is wound onto the spool 40. The speed at which the spool 40 winds the filament 5 can be adjusted by the filament winder 50. The speed at which the spool 40 winds the filament 5 is adjusted to correspond to the speed at which the twin-screw extruder 20 pushes out the filament 5. More specifically, the speed at which the spool 40 winds the filament 5 is adjusted to be equal to the speed at which the twin-screw extruder 20 pushes out the filament 5. The speed at which the spool 40 winds the filament 5 is, for example, between 3 m / min and 5 m / min. By winding the filament 5 at an appropriate speed, the line width of the filament 5 is kept approximately constant.

[0032] Through the above process, a filament 5 wound onto a spool 40 is manufactured. Because the proportion of resin material in the manufactured filament 5 is continuously changed along the longitudinal direction dL, the physical properties of the filament 5 differ along the longitudinal direction dL. The line width of the manufactured filament 5 is kept approximately constant.

[0033] This section describes a manufacturing apparatus 60 for three-dimensional structures using filament 5. The manufacturing apparatus 60 for three-dimensional structures is a so-called 3D printer. Figure 6 shows a schematic representation of the manufacturing apparatus 60 for three-dimensional structures. In the example shown in Figure 6, the manufacturing apparatus 60 for three-dimensional structures includes a spool 40, a stand 70, and a nozzle 80. The spool 40 is made by winding the filament 5 manufactured by the filament manufacturing apparatus 10 described above. The spool 40 rotates, allowing the filament 5 to be fed out.

[0034] The stand 70 properly supports the spool 40. The stand 70 is positioned vertically above the nozzle 80. Figure 7 shows the stand 70 supporting the spool 40. As indicated by the arrows in Figure 7, the stand 70 can properly adjust the position of the filament 5 extending from the spool 40 to the nozzle 80. Specifically, the stand 70 is rotatable in a rotational direction dR about its vertical axis and is movable in a direction toward and away from the nozzle 80 dx. By rotating and moving the stand 70, the spool 40 is moved to the appropriate position, allowing the filament 5 to be easily fed from the spool 40 to the nozzle 80.

[0035] The nozzle 80 melts and injects the filament 5. The inside of the nozzle 80 is heated to melt the filament 5. The filament 5 extends from the spool 40 to the nozzle 80. The filament 5 is continuously supplied to the nozzle 80. A three-dimensional structure 1 is manufactured by stacking the filaments 5 injected from the nozzle 80. The nozzle 80 is movable so that the filaments 5 can be stacked in positions corresponding to the shape of the manufactured three-dimensional structure 1. The inner diameter of the injection hole from which the nozzle 80 injects the molten filament 5 is, for example, 0.4 mm or more and 0.6 mm or less. To suppress clogging of the filament 5 inside the nozzle 80, it is preferable that the inside of the nozzle 80 is coated with Teflon.

[0036] An example of a method for manufacturing a three-dimensional structure using the three-dimensional structure manufacturing apparatus 60 described above, with the filament 5 wound on the spool 40, will now be explained. The method for manufacturing a three-dimensional structure includes the steps of melting the filament 5 and moving the nozzle 80 while extruding the molten filament 5 from the nozzle 80.

[0037] The filament 5 is melted. The filament 5 melts in the nozzle 80 as the temperature of the nozzle 80 rises. The inside of the nozzle 80 is coated with Teflon, which prevents the molten filament 5 from clogging.

[0038] The nozzle 80 is moved while the molten filament 5 is extruded from it. By moving the nozzle 80, the filament 5 can be extruded to the desired position. Figure 8 shows the process of extruding the filament 5 from the nozzle 80. As shown in Figure 8, the extruded filament 5 overlaps in the first direction d1, thereby manufacturing the three-dimensional structure 1. In the manufacturing process of the three-dimensional structure 1, the first direction d1 is, for example, the vertical direction.

[0039] As the nozzle 80 moves, the orientation of the nozzle 80 relative to the rotational direction of the spool 40 can change continuously. By rotating the stand 70 supporting the spool 40 in the rotational direction dR, the filament 5 being fed from the spool 40 can be oriented toward the nozzle 80. The resistance the filament 5 experiences when being fed from the spool 40 can be reduced. Depending on the orientation of the filament 5 extending from the spool 40, the filament 5 may come into contact with other components and experience resistance. The stand 70 supporting the spool 40 can move in a direction dx toward or away from the nozzle 80 to prevent the filament 5 from coming into contact with other components of the three-dimensional structure manufacturing apparatus 60. The possibility of the filament 5 coming into contact with other components and experiencing resistance can be reduced.

[0040] Conventional filaments, if their physical properties change continuously, can be unsuitable for manufacturing three-dimensional structures. For example, if a portion of the filament is too soft, using that soft portion can clog the nozzles of the manufacturing equipment used to create three-dimensional structures.

[0041] In this embodiment, the filament 5 has a continuously changing mixing ratio of two or more resins along its longitudinal direction, and the difference between the maximum and minimum line width of the filament 5 is 0.1 mm or less. In this embodiment, the filament 5 has a continuously changing physical property due to the continuously changing mixing ratio of the resins, and the line width is substantially constant. By using such a filament 5, a three-dimensional structure 1 can be appropriately manufactured by the three-dimensional structure manufacturing apparatus 60, and the physical properties of the manufactured three-dimensional structure 1 can be continuously changed.

[0042] Filament 5 contains a thermoplastic elastomer and a polyolefin. The polyolefin is a relatively hard resin, and the thermoplastic elastomer is a relatively soft resin. By continuously changing the mixing ratio of these resins, the physical properties of filament 5 can be appropriately and continuously changed.

[0043] At any position along the longitudinal direction of the filament 5, the proportion of thermoplastic elastomer is 80% by mass or less. If there is too much thermoplastic elastomer in the filament 5, the filament 5 becomes too soft and clogs inside the nozzle 80. The inventors confirmed that when the proportion of thermoplastic elastomer at any position along the longitudinal direction of the filament 5 is greater than 80% by mass, the filament 5 clogs inside the nozzle 80. When the thermoplastic elastomer in the filament 5 is 80% by mass or less, the filament 5 does not clog inside the nozzle 80, and the three-dimensional structure 1 can be manufactured.

[0044] The filament manufacturing apparatus 10 for producing the filament 5 of this embodiment includes a twin-screw extruder 20, a cooling fan 30, a spool 40, and a filament winder 50. The twin-screw extruder 20 melts and mixes two or more different resin materials and extrudes the filament 5 from the extrusion port 24. By continuously changing the proportion of resin materials, the physical properties of the manufactured filament 5 can be appropriately and continuously changed. The cooling fan 30 cools the filament 5 extruded from the extrusion port 24. By quickly cooling the filament 5 extruded from the extrusion port 24, stretching of the filament 5 can be suppressed. The filament winder 50 adjusts the speed at which the spool 40 winds the filament 5. By winding the filament 5 at an appropriate speed, stretching of the filament 5 can be suppressed. Stretching of the filament 5 and resulting narrowing of the line width are suppressed. The filament manufacturing apparatus 10 of this embodiment makes it possible to manufacture a filament 5 whose physical properties change continuously and whose line width is substantially constant.

[0045] The cooling fan 30 is positioned vertically below the filament 5. The cooling fan 30 cools the filament 5 by blowing air onto it vertically from below. The blown air causes the filament 5 to experience an upward force in the vertical direction. This reduces the downward vertical stretching of the filament 5 due to gravity. It also suppresses the thinning of the line width due to the stretching of the filament 5.

[0046] The rotation speed of the cooling fan 30 is between 2500 rpm and 3000 rpm. The rotation speed of the cooling fan 30 is not too high, which prevents the filament 5 from shaking due to the blown air and causing unstable winding of the filament 5 by the spool 40. The rotation speed of the cooling fan 30 is not too low, which prevents the filament 5 from stretching and becoming thinner when wound onto the spool 40 due to insufficient cooling of the filament 5.

[0047] In the vertical direction, the position where the spool 40 winds the filament 5 is higher than the extrusion port 24. This prevents the filament 5 from bending and becoming thinner as it is wound onto the spool 40 after being extruded from the extrusion port 24.

[0048] The speed at which the spool 40 winds the filament 5 is adjusted to correspond to the speed at which the twin-screw extruder 20 pushes out the filament 5. If the speed at which the spool 40 winds the filament 5 is too fast relative to the speed at which the twin-screw extruder 20 pushes out the filament 5, the filament 5 will not stretch and its width will not decrease. If the speed at which the spool 40 winds the filament 5 is too slow relative to the speed at which the twin-screw extruder 20 pushes out the filament 5, the extruded filament 5 will not clump together and its width will not increase.

[0049] The speed at which the spool 40 winds the filament 5 is between 3 m / min and 5 m / min. The speed at which the spool 40 winds the filament 5 can be adjusted to an appropriate speed corresponding to the speed at which the twin-screw extruder 20 pushes out the filament 5.

[0050] In the three-dimensional structure manufacturing apparatus 60, the inside of the nozzle 80 is coated with Teflon. Because Teflon has excellent lubricity, clogging of the molten filament 5 inside the nozzle 80 is suppressed. In particular, when the filament 5 is soft, in other words, when the proportion of thermoplastic resin contained in the filament 5 is large, the Teflon coating inside the nozzle 80 can significantly suppress clogging of the molten filament 5 inside the nozzle 80.

[0051] In the three-dimensional structure manufacturing apparatus 60, the stand 70 is rotatable and movable in a direction toward and toward the nozzle 80. By rotating the stand 70 that supports the spool 40 so that the filament 5 fed from the spool 40 faces toward the nozzle 80, the resistance the filament 5 experiences when it is fed from the spool 40 can be reduced. By moving the stand 70 that supports the spool 40 toward or toward the nozzle 80, the possibility of the filament 5 coming into contact with other components and experiencing resistance can be reduced. The filament 5 can be properly fed from the spool 40 to the nozzle 80.

[0052] The mixing ratio of two or more resins contained in the three-dimensional structure 1 manufactured using the filament 5 by the three-dimensional structure manufacturing apparatus 60 changes continuously along the first direction d1. By using the filament 5, it is possible to obtain a three-dimensional structure 1 in which the physical properties change continuously along the first direction d1. For example, it is possible to obtain a three-dimensional structure 1 in which the hardness and color change continuously along the first direction d1.

[0053] As described above, in this embodiment, the mixing ratio of two or more resins in the filament 5 changes continuously along the longitudinal direction, and the difference between the maximum and minimum line widths of the filament 5 is 0.1 mm or less. By manufacturing a three-dimensional structure 1 using the filament 5, the physical properties of the three-dimensional structure 1 can be continuously changed.

[0054] The embodiments of this disclosure are not limited to those described above, but include various modifications that a person skilled in the art could conceive, and the effects of this disclosure are not limited to those of the embodiments described above. Various additions, modifications, and partial deletions are possible, provided that they do not depart from the conceptual idea and spirit of each disclosure derived from the claims and their equivalents. [Examples]

[0055] The present disclosure will be described in more detail below using examples, but the present disclosure is not limited to the following examples. For example, the conditions for manufacturing the filament 5 and the proportion of thermoplastic elastomer contained in the filament 5 can be appropriately selected depending on the type of thermoplastic elastomer and polyolefin used.

[0056] Filaments were manufactured using a filament manufacturing apparatus under the following conditions. Pellets of polypropylene (Prime Polypro J105G, manufactured by Prime Polymer Co., Ltd.), a type of polyolefin, and / or pellets of olefin-based thermoplastic elastomer (Milastomer 6030NS, manufactured by Mitsui Chemicals, Inc.), a thermoplastic resin, were fed into the inlet of the twin-screw extruder of the filament manufacturing apparatus. The proportion of materials to be fed differed between the examples and comparative examples. The internal temperature of the twin-screw extruder cylinder was 180°C, and the screw rotation speed was 10 rpm. The inner diameter of the extrusion port was 1.75 mm.

[0057] Cooling fans (Mauknci MU-8CM2KI) were positioned to cool the filament being extruded from the twin-screw extruder. Four 80mm diameter cooling fans were lined up along the direction in which the filament extended. The spacing between the cooling fans was 30mm. The cooling fans were positioned below the filament in the vertical direction. The rotation speed of the cooling fans was 2800rpm.

[0058] A filament winder (Noztek Filament Winder 1.0, manufactured by Noztek) was positioned to wind the filament onto the spool at a desired speed. The winding speed of the filament winder was 4 m / min.

[0059] Filaments according to the examples and comparative examples were manufactured by continuously changing the ratio of resin material fed into the twin-screw extruder of the filament manufacturing apparatus. The filament of Example 1 was manufactured by continuously changing the ratio of polypropylene to olefin-based thermoplastic elastomer fed into the twin-screw extruder from 10:0 to 2:8. The filament of Example 2 was manufactured by continuously changing the ratio of polypropylene to olefin-based thermoplastic elastomer fed into the twin-screw extruder from 2:8 to 10:0. The filament of Comparative Example 1 was manufactured by feeding only polypropylene into the twin-screw extruder. The filament of Comparative Example 2 was manufactured by keeping the ratio of polypropylene to olefin-based thermoplastic elastomer fed into the twin-screw extruder constant at 2:8.

[0060] Using the filaments of each example and comparative example, the test three-dimensional structure 3 shown in Figure 9 was manufactured using a three-dimensional structure manufacturing apparatus (Raise3D Pro 2). In the three-dimensional structure manufacturing apparatus, the internal temperature of the nozzle (Raise 3D genuine nozzle J3D0F7) was set to 240°C, and the filament extrusion speed from the nozzle was set to 30 mm / second. The inner diameter of the nozzle's injection hole was 0.5 mm. The inside of the nozzle was coated with Teflon.

[0061] The spool on which the filament is wound is supported by a stand (Raise 3D swivel stand RSJP3D-02). The stand is rotatable and can move towards and away from the nozzle. As the stand rotates and moves appropriately, the filament is fed from the spool to the nozzle.

[0062] The three-dimensional test structure 3 manufactured was cylindrical, with a height of 20 mm, a width of 40 mm, a length of 200 mm, and a thickness of 5 mm. A cantilever bending test was performed on the three-dimensional test structures using the filaments of each example and each comparative example using the test apparatus 90 (tabletop test machine, Shimadzu Corporation EZ-S).

[0063] In the cantilever beam bending test, as shown in Figure 10, one end of the three-dimensional test structure 3 in the longitudinal direction was fixed to a jig 91, and as shown in Figure 11, a force was applied to the other end from above to below by a load-bearing part 95, and the displacement X of the other end was measured. In the three-dimensional test structure 3 of Example 1, the portion near the end fixed to the jig 91 contained a large amount of polypropylene, and the portion near the other end to which the force was applied by the load-bearing part 95 contained a large amount of olefin-based thermoplastic elastomer. In the three-dimensional test structure 3 of Example 2, the portion near the end fixed to the jig 91 contained a large amount of olefin-based thermoplastic elastomer, and the portion near the other end to which the force was applied by the load-bearing part 95 contained a large amount of polypropylene. To ensure that the load is applied appropriately, a cover (not shown) is provided at the other end of the three-dimensional test structure 3.

[0064] Figure 12 shows the relationship between the displacement X at the other end and the force applied by the load-bearing section 95 for each three-dimensional test structure 3 of each embodiment and comparative example.

[0065] In Figure 12, a comparison between Examples 1 and 2 and Comparative Examples 1 and 2 shows that the resin in the portion near the fixed end affects the tendency of the physical properties when a load is applied to the other end. A comparison between Example 1 and Comparative Example 1, and between Example 2 and Comparative Example 2, shows that the mixing ratio of materials contained in the filament used to manufacture the three-dimensional structure changes continuously along the longitudinal direction, resulting in a continuous change in the physical properties of the three-dimensional structure. A comparison between Example 1 and Example 2 shows that even if the physical properties of the three-dimensional structure change continuously in a similar manner, the physical properties differ significantly if the resin in the portion near the fixed end is different. [Explanation of Symbols]

[0066] 1 Three-dimensional structure 3. Three-dimensional structure for testing 5 filaments 10 Filament manufacturing equipment 20 Twin-screw extruder 21 Inlet 22 volts 23 Screw 24 Extrusion port 30 Cooling Fans 40 spools 50 Filament Winder 60 Manufacturing equipment for three-dimensional structures 70 Stands 80 nozzles 90 Test equipment 91 Jig 95 Weighted part

Claims

1. A twin-screw extruder that melts and mixes two or more different resin materials and continuously extrudes filaments from an extrusion port, A cooling fan for cooling the filament extruded from the extrusion port, A spool for winding the aforementioned filament, The spool comprises a filament winder that adjusts the speed at which it winds the filament, A filament manufacturing apparatus in which, in the vertical direction, the position where the spool winds the filament is higher than the extrusion port.

2. A twin-screw extruder that melts and mixes two or more different resin materials and continuously extrudes filaments from an extrusion port, A cooling fan for cooling the filament extruded from the extrusion port, A spool for winding the aforementioned filament, The spool comprises a filament winder that adjusts the speed at which it winds the filament, A filament manufacturing apparatus in which the spool winds the filament at a speed of 3 m / min or more and 5 m / min or less.

3. The filament manufacturing apparatus according to claim 1 or 2, wherein the cooling fan is positioned vertically below the filament.

4. The filament manufacturing apparatus according to claim 1 or 2, wherein the rotational speed of the cooling fan is 2,500 rpm or more and 3,000 rpm or less.

5. A twin-screw extruder that melts and mixes two or more different resin materials and continuously extrudes filaments from an extrusion port, A cooling fan for cooling the filament extruded from the extrusion port, A spool for winding the aforementioned filament, A method for manufacturing a filament using a filament manufacturing apparatus comprising a filament winder that adjusts the speed at which the spool winds the filament, A method for manufacturing a filament, comprising the step of extruding the filament while continuously changing the ratio of two or more different resin materials that are melted and mixed by the twin-screw extruder.

6. The spool includes the step of winding the filament, The method for manufacturing a filament according to claim 5, wherein the speed at which the spool winds the filament is adjusted by the filament winder to a speed corresponding to the speed at which the twin-screw extruder pushes out the filament.

Images