Filament and method for producing shaped article

Abstract

Provided are: a filament having good flexibility and high tensile strength and flexural rigidity; and a method for producing a shaped object by which a shaped object having excellent strength characteristics can be produced from the filament. The filament according to the present invention is used as a shaping raw material for a 3D printer, a matrix resin is impregnated in fiber bundles including continuous reinforcing fibers, the fiber bundles include a first fiber bundle group and a second fiber bundle group, and the twist angle of the first fiber bundle group is smaller than the twist angle of the second fiber bundle group.

Description

Technical Field

[0001] The present invention relates to a method for producing a filament and a shaped object. Background Art

[0002] In order to improve the mechanical strength of the object, the use of 3D printers that use continuous fiber-reinforced resin strands to form fiber-reinforced resin (FRP) is expanding. Such 3D printers are used in the manufacturing process of jigs, parts, and bicycle frames, for example.

[0003] Patent document 1 discloses the following: A filament (strand) for a 3D printer using a hot melt lamination method includes a base material having a thermoplastic resin as a main component, one or more fibers or fiber bundles impregnated in the base material and extending axially, and these fibers or fiber bundles are twisted axially.

[0004] Patent document 1: Japanese Patent Application Publication No. 2021-123026.

[0005] Fig. 7A and Figure 7B The filament 5 shown has a fiber bundle 3, and the fiber bundle 3 is twisted so that a plurality of fibers 1 have an orientation angle inclined in the axial direction. According to the filament 5, when a shaped object is formed by a hot melt lamination method, the filament 5 can obtain good flexibility. However, in the case of the filament 5, since the fiber bundle 3 is twisted as a whole, there is a possibility that the tensile strength and bending rigidity in the axial direction are reduced.

[0006] When a shape is formed by hot melt lamination, the thermoplastic resin of the filament 5 is melted from a head having a heating mechanism, and the fiber bundle 3 and the molten resin are ejected from a nozzle attached to the head, and are stacked on a workbench or a layer of a base consisting of an already ejected printing path. At this time, if the entire fiber bundle 3 of the filament 5 is twisted, it is difficult to open the fiber bundle 3 ejected from the nozzle, and the fiber 1 is not fully fused to the workbench or the base. In addition, the fiber 1 is easily unevenly dispersed during the formation. Therefore, there is a possibility that the strength of the manufactured shape is reduced and uneven strength occurs. Summary of the invention

[0007] Therefore, an object of the present invention is to provide a filament having good flexibility and high tensile strength and flexural rigidity, and a method for producing a shaped object capable of producing a shaped object having excellent strength characteristics using the filament.

[0008] The present invention is constituted by the following structure.

[0009] (1) A filament used as a molding material for a 3D printer, wherein a fiber bundle including continuous reinforcing fibers is impregnated with a matrix resin, the fiber bundle comprising a first fiber bundle group and a second fiber bundle group, the first fiber bundle group having a twist angle smaller than a twist angle of the second fiber bundle group.

[0010] (2) A method for producing a shaped object, comprising: heat-melting the filaments of (1), and ejecting the heat-melted forming material to form the shaped object in layers.

[0011] Effects of the Invention

[0012] According to the present invention, a filament having good flexibility and high tensile strength and bending rigidity can be obtained. In addition, by using the filament to produce a shaped object, a shaped object with excellent strength characteristics can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic diagram of the structure of a FDM-based layer-by-layer molding device.

[0014] Figure 2A It is a cross-sectional view of the filament in the radial direction orthogonal to the axial direction.

[0015] Figure 2B is a side view of the fibril.

[0016] Figure 3A This is a cross-sectional view of the filament of Modification Example 1 in the radial direction.

[0017] Figure 3B This is a side view of the filament of Modification Example 1.

[0018] Figure 4A This is a cross-sectional view of the filament of Modification Example 2 in the radial direction.

[0019] Figure 4B This is a side view of the filament of Modification Example 2.

[0020] Figure 5 This is a cross-sectional view of the filament of Modification Example 3 in the radial direction.

[0021] Figure 6 This is a schematic perspective view of a filament production device.

[0022] Fig. 7A This is a radial cross-sectional view of a conventional filament.

[0023] Figure 7B This is a side view of a conventional fibril. DETAILED DESCRIPTION

[0024] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0025] First, the structure of a 3D printer will be briefly described. The layer-additive manufacturing device shown here is an example of a 3D printer, and other structures are also possible.

[0026] <Structure of the layer-building device>

[0027] Figure 1 FIG. 1 is a schematic diagram of the structure of a FDM-based layer-additive manufacturing apparatus 100 .

[0028] The laminated molding device 100 includes a filament feeding unit 13 for feeding fiber-reinforced resin filaments (hereinafter also referred to as filaments) 11 , a head 15 , a table 17 , a molding drive unit 19 , and a control unit 21 .

[0029] The filament feeding unit 13 includes a pair of driving rollers 13a for sandwiching the filaments 11 and a driving unit (not shown) such as a motor for rotationally driving at least one of the driving rollers 13a.

[0030] The head 15 has a heating unit (not shown) for thermally melting the fed filaments 11 and a nozzle 15a for ejecting the melted molding material by the heating unit. In addition, although not shown, a cutting unit such as a cutter or a laser cutting device for cutting the reinforcing fibers contained in the filaments 11 may also be provided.

[0031] The table 17 has a shaping surface 17a which is arranged to face the nozzle 15a of the head 15 and on which the shaped objects are stacked.

[0032] The forming drive unit 19 moves the head 15 and the worktable 17 relative to each other, and forms the forming material ejected from the nozzle 15a of the head 15 along a desired path. For example, the forming drive unit 19 may also be configured to include a two-axis driving mechanism for moving the head 15 within the surface of the forming surface 17a of the worktable 17, and a lifting mechanism for adjusting the stacking height by lifting and lowering the worktable 17.

[0033] The control unit 21 has the function of controlling the feeding of the filament 11 by the filament feeding unit 13 and the relative movement of the head 15 by the forming drive unit 19, and the function of comprehensively controlling other parts. A program for controlling each part including the filament feeding unit 13 and the forming drive unit 19 is input to the control unit 21, and a desired shape of the object is formed by layering by executing the program.

[0034] <Method of manufacturing the object>

[0035] In the lamination forming apparatus 100 of this structure, the filaments 11 are fed to the head 15 by the control unit 21, and the fed filaments 11 are heat-melted by the head 15. Then, a forming process is performed, in which the forming material melted by the filaments 11 is ejected from the nozzle 15a of the head 15 while the head 15 and the worktable 17 are relatively moved. Thus, a desired shape of the formed object is formed on the worktable 17.

[0036] <Fibril structure>

[0037] Next, the structure of the filament 11 will be described.

[0038] Figure 2A It is a cross-sectional view of the filament 11 in the radial direction orthogonal to the axial direction. Figure 2B is a side view of the filament 11.

[0039] like Figure 2A and Figure 2B As shown, the filament 11 is a linear resin material used as a forming material of a 3D printer such as the above-mentioned layered forming device 100, and a matrix resin (hereinafter also simply referred to as resin) 27 composed of a thermoplastic resin is impregnated in a fiber bundle 25 including continuous reinforcing fibers 23. In addition, the matrix resin 27 is not limited to a thermoplastic resin, and for example, it may be other resin materials such as a thermosetting resin.

[0040] The filament 11 includes a first fiber bundle group 31 and a second fiber bundle group 33 as the fiber bundle 25. The first fiber bundle group 31 is arranged along the filament central axis O, and the second fiber bundle group 33 is arranged around the first fiber bundle group 31. The second fiber bundle group 33 is arranged radially outside the first fiber bundle group 31, and is twisted around the first fiber bundle group 31. The first fiber bundle group 31 arranged along the filament central axis O is arranged parallel to the filament central axis O. In addition, the orientation direction of the reinforcing fibers 23 constituting the first fiber bundle group 31 is aligned parallel to the filament central axis O.

[0041] The first fiber bundle group 31 may be twisted around the filament central axis O. In this case, the twist angle of the first fiber bundle group 31 is smaller than the twist angle of the second fiber bundle group 33 .

[0042] The reinforcing fibers 23 of the fiber bundle 25 of the filaments 11 can be made of organic fibers such as polyethylene fibers, aramid fibers, and Zylon fibers, or inorganic fibers such as boron fibers, glass fibers, carbon fibers, metal fibers, and rock fibers. The reinforcing fibers can be surface-treated fibers to increase the adhesion between the resin and the fibers.

[0043] The thermoplastic resin used as the main component of the matrix resin 27 of the filament 11 may be a polyolefin resin such as polypropylene or polyethylene, an acrylonitrile-butadiene-styrene resin, a polystyrene resin, a polyester resin such as polyethylene terephthalate, polybutylene terephthalate or polylactic acid, a polyamide resin, an aromatic polyamide resin, polyetherimide, polyallyl imide, polyarylate, polyetheretherketone, polyallyletherketone, polybenzimidazole, polyethersulfone, polysulfone, polyvinylidene fluoride resin, a liquid crystal polymer, a polycarbonate resin, polyacetal or polyphenylene sulfide, etc.

[0044] These thermoplastic resins may be used alone or in combination with a plurality of resins to improve the heat resistance, heat deformation temperature, heat aging, tensile properties, bending properties, creep properties, compression properties, fatigue properties, impact properties, and sliding properties of the thermoplastic resin. Examples of thermoplastic resins include polyetheretherketone (PEEK) / polytetrafluoroethylene (PTFE), PEEK / polybenzimidazole (PBI), and the like. In addition, the thermoplastic resin may be a resin to which short fibers such as carbon fiber and glass fiber, talc, and the like are added.

[0045] Antioxidants such as phenol, thioether, and phosphite, ultraviolet absorbers such as benzotriazole or triazine, and metal inactivators such as hydrazide or amide may be added to the thermoplastic resin to improve the durability of the shaped object.

[0046] When a phthalate-based, polyester-based or other plasticizer is added to a thermoplastic resin, the flexibility is improved, and the molding accuracy during molding and the flexibility of the molded product can be improved.

[0047] When a halogen-based, phosphate-based, inorganic-based, or intumescent-based flame retardant is added to a thermoplastic resin, the flame retardancy of the resulting article can be improved.

[0048] When a core material such as a phosphoric acid ester metal salt or sorbitol is added to a thermoplastic resin, thermal expansion during molding can be controlled and molding accuracy can be improved.

[0049] If a permanent antistatic agent such as a nonionic, anionic, or cationic antistatic agent is added to a thermoplastic resin, the antistatic property of the resulting article can be improved.

[0050] By adding a lubricant such as a hydrocarbon-based or metal soap-based lubricant to the thermoplastic resin, the lubricity of the continuous fiber-reinforced filaments is improved, and the filaments can be smoothly fed out during molding.

[0051] In the filaments used in 3D printers, the flexibility can be improved by twisting the fiber bundle, but the orientation angle of the reinforcing fibers in the fiber bundle is tilted relative to the axial direction, so the tensile strength and bending rigidity in the axial direction may decrease. In addition, if the fiber bundle is twisted as a whole, it is difficult for the fiber bundle ejected from the nozzle to open when the object is formed by hot melt lamination. Figure 1 The fusion of the workbench 17 or the base shown in the figure becomes insufficient, and sometimes the reinforcing fibers are unevenly dispersed during the formation. In addition, since the fiber bundle is not easy to open, gaps are likely to be formed between adjacent filaments when viewed from above. Therefore, the strength of the formed object may decrease and the strength may be uneven.

[0052] Therefore, in the filament 11 of the present embodiment, the fiber bundle 25 including the continuous reinforcing fiber 23 includes a first fiber bundle group 31 and a second fiber bundle group 33, and the twist angle of the first fiber bundle group 31 is smaller than the twist angle of the second fiber bundle group 33. Thus, the filament 11 has good flexibility due to the second fiber bundle group 33, and the tensile strength and bending rigidity are improved by the first fiber bundle group 31.

[0053] When the filaments 11 are used to shape an object, the second fiber bundle group 33 is twisted at a larger twist angle than the first fiber bundle group 31, so the flexibility of the second fiber bundle group 33 is improved. Therefore, when printing a curvature portion, the filaments 11 can easily follow the curvature, and the shaping accuracy is improved.

[0054] In addition, the first fiber bundle group 31 is such that the fiber bundle 25 is smoothly opened when ejected from the nozzle, and the reinforcing fibers 23 are evenly dispersed during the molding, so that the fibers are well fused to the workbench or the base. Furthermore, the fiber bundle 25 is easily opened, so that it is difficult to generate gaps between adjacent filaments 11 when viewed from above, and they are easily gathered.

[0055] Due to the synergistic effect of the first fiber bundle group 31 and the second fiber bundle group 33 described above, a high-strength shaped product with suppressed strength variation can be easily obtained.

[0056] In particular, when the orientation direction of the reinforcing fibers 23 of the first fiber bundle group 31 is aligned parallel to the filament axial direction, increases in the tensile strength and bending rigidity of the first fiber bundle group 31 become significant.

[0057] Next, modified examples of the above-mentioned filament 11 will be described.

[0058] (Variant 1)

[0059] Figure 3A This is a cross-sectional view of the filament 11A according to Modification 1 in the radial direction. Figure 3B This is a side view of a filament 11A according to Modification 1.

[0060] like Figure 3A and Figure 3B As shown, in the filament 11A described in Modification 1, the first fiber bundle group 31 arranged along the filament central axis O is arranged parallel to the filament central axis O. A twist is applied to the second fiber bundle group 33 arranged radially outside the first fiber bundle group 31, centered on the first fiber bundle group 31. And the orientation direction of the reinforcing fiber 23 constituting the first fiber bundle group 31 is aligned parallel to the filament central axis O. In addition, in the filament 11A of Modification 1, the outer periphery (radially outer side) of the second fiber bundle group 33 is covered with a resin 35. The resin 35 is preferably the same material as the aforementioned matrix resin 27. The regions of the first fiber bundle group 31 and the second fiber bundle group 33 may be impregnated with the resin 35, or may be impregnated with the aforementioned matrix resin 27. In addition, in this embodiment, a twist may be applied to the first fiber bundle group 31, centered on the filament central axis O. In this case, the twist angle of the first fiber bundle group 31 is smaller than the twist angle of the second fiber bundle group 33.

[0061] According to the filament 11A, the outer periphery of the second fiber bundle group 33 is covered with the resin 35, so it has good flexibility, and the tensile strength and bending rigidity are improved by the first fiber bundle group 31. In addition, the reinforcing fibers 23 of the second fiber bundle group 33 provided outside the first fiber bundle group 31 can be protected by the resin 35.

[0062] (Variant 2)

[0063] Figure 4A This is a cross-sectional view of the filament 11B according to the second modification in the radial direction. Figure 4B This is a side view of the filament 11B described in Modification Example 2.

[0064] like Figure 4A and Figure 4B As shown, in the case of the filament 11B described in the modification example 2, the outer periphery (radially outer side) of the second fiber bundle group 33 is covered with a resin 35, similarly to the filament 11A described in the modification example 1. Furthermore, in the filament 11B, a groove 37 is formed on its outer peripheral surface. A plurality of grooves 37 are formed at equal intervals along the circumference of the filament 11B, and are formed spirally along the filament axial direction. In addition, the grooves 37 may be replaced with convex strips protruding radially outward formed on the outer peripheral surface of the filament 11B.

[0065] According to the filament 11B described in this modification example 2, the surface area of ​​the outer peripheral surface can be increased by means of the grooves 37 or the convex strips, thereby improving the flexibility. In addition, the above-mentioned grooves 37 or convex strips are not limited to spiral shapes, but can also be linear along the axial direction of the filament 11B. In addition, it can also be configured to provide a plurality of annular grooves or annular protrusions continuously formed in the circumferential direction of the filament 11B along the axial direction of the filament 11B. In addition, the above-mentioned grooves and convex strips can also be configured in combination. That is, on the filament 11B, at least one of spiral or linear concave-convex along the axial direction of the filament, or a plurality of annular concave-convex arranged along the axial direction of the filament is formed on its outer peripheral surface.

[0066] (Variant 3)

[0067] Figure 5 This is a cross-sectional view of a filament 11C according to Modification 3 in the radial direction.

[0068] like Figure 5 As shown, in the filament 11C described in the modification example 3, the first fiber bundle group 31 and the second fiber bundle group 33 are arranged opposite to those in the filament 11 when viewed in cross section. That is, the second fiber bundle group 33 is arranged along the filament central axis O, and the first fiber bundle group 31 is arranged around the second fiber bundle group 33.

[0069] The second fiber bundle group 33 arranged along the filament central axis O is twisted relative to the filament central axis O, and the first fiber bundle group 31 arranged around the second fiber bundle group 33 is arranged parallel to the filament central axis O. In addition, the orientation direction of the reinforcing fibers 23 constituting the first fiber bundle group 31 is aligned parallel to the filament central axis O.

[0070] According to the filament 11C, the second fiber bundle group 33 arranged radially inward of the first fiber bundle group 31 is twisted. This structure also has good flexibility and the first fiber bundle group 31 can improve tensile strength and bending rigidity.

[0071] In Modification 3, the first fiber bundle group 31 may be twisted around the filament central axis O. In this case, the twist angle of the first fiber bundle group 31 is smaller than the twist angle of the second fiber bundle group 33 .

[0072] <Fiber production method>

[0073] Next, the method for producing the above-mentioned filaments will be described. The filament production apparatus shown here is an example and the present invention is not limited thereto.

[0074] Figure 6 2 is a schematic structural diagram of a filament production device 200 .

[0075] The filament manufacturing device 200 includes a plurality of fiber material supply sections 51 for delivering coiled fiber bundles 25 at a predetermined speed, a kneading extruder 65 for kneading and melting a resin, and a resin bath section 67 for impregnating the fiber bundles 25 delivered from the fiber material supply section 51 with the resin plasticized by the kneading extruder 65 .

[0076] The filament production apparatus 200 includes a cooling section 71 disposed on the downstream side of the resin bath section 67, and a twisting section 81 disposed on the downstream side of the cooling section 71. The composite (impregnated fiber material) 41 after the fiber bundle 25 is impregnated with resin is sent out from the resin bath section 67. The cooling section 71 cools the composite 41 sent out from the resin bath section 67. The twisting section 81 mainly applies a twist around the axis center to the fiber bundle 25 before cooling.

[0077] The kneading extruder 65 is equipped with a screw shaft (not shown) having kneading wings rotatably in a cavity 66 whose interior is hollow, and melts and plasticizes the resin fed from the hopper 63 .

[0078] The resin bath section 67 is formed into a cylindrical shape with the cylinder axis direction facing up and down, and the resin 35 plasticized by the kneading extruder 65 is supplied and stored inside the cylinder. The upper end of the resin bath section 67 is open, and the fiber bundle 25 guided by the guide roller 53 is pulled into the resin stored in the resin bath section 67 from the upper end opening.

[0079] A plurality of impregnation rollers (not shown) rotatably held with their axes oriented in the horizontal direction are provided inside the resin bath 67. The fiber bundle 25 introduced from the upper end opening of the resin bath 67 sequentially passes over the impregnation rollers and is sent to the outlet 68.

[0080] A die 69 is provided at the outlet 68 at the lower end of the resin bath 67 to shape the outer periphery of the composite 41 of the resin and the fiber bundle 25 when the composite 41 is drawn out to the outside. According to the opening shape of the die 69, grooves 37, convex stripes and other concave and convex surfaces can be formed on the outer periphery of the filament.

[0081] The cooling section 71 is a long water tank arranged along the direction of extraction of the composite body 41 from the resin bath section 67, and the cooling water 72 is stored in the tank. In the cooling section 71, the resin impregnated in the fiber bundle 25 of the composite body 41 is cooled in the cooling water 72 to be hardened.

[0082] The twisting section 81 shown here includes a pair of upper and lower pulling rollers 83 and 85 disposed on the downstream side of the cooling section 71 so that the outer peripheral surfaces thereof are in contact with each other. Various mechanisms can be adopted for such a twisting section 81. For example, although not shown in the figure, various structures such as a mechanism for rotating the bobbin around the axis of the filament 11 can be adopted.

[0083] The pulling rollers 83 and 85 have the function of pulling the fiber bundle 25 from the fiber material supply section 51 into the resin bath section 67 and then extracting the composite 41 from the resin bath section 67 to the cooling section 71 and the twisting section 81. In addition, a winding section (not shown) is separately provided on the downstream side of the twisting section 81 to wind the obtained filament 11 on a bobbin.

[0084] The production process of the filament 11 using the above-mentioned filament production apparatus 200 is as follows.

[0085] (Impregnation process)

[0086] The impregnation step is performed by means of the resin bath section 67 of the filament production device 200. Specifically, the resin supplied from the hopper 63 is kneaded by the kneading extruder 65, and the molten resin is stored in the resin bath section 67. The fiber bundle 25 is supplied to the resin bath section 67 from the fiber material supply section 51. In the resin bath section 67, the fiber bundle 25 is impregnated with the molten resin, and the impregnation amount is adjusted by passing through the die 69 arranged at the outlet section 68. By this impregnation, the matrix resin is present in the gaps in each fiber bundle 25, around each fiber bundle 25, and between each fiber bundle 25. The composite 41 of the matrix resin and the fiber bundle 25 obtained in this way is cooled in the cooling section 71.

[0087] (Twisting process)

[0088] In the twisting step, the fiber bundle 25 impregnated with the resin in the resin bath section 67 is twisted by the twisting section 81. Specifically, the composite 41 that has passed through the cooling section 71 is passed through the roller gap between the drawing rollers 83 and 85 of the twisting section 81 while being rotated. Thus, the fiber bundle 25 is twisted. In this example, the second fiber bundle group 33 on the outer peripheral side of the first fiber bundle group 31 along the filament center axis O is twisted. In addition, by adjusting the inclination angle of the above-mentioned drawing rollers 83 and 85 with respect to the drawing direction, the number of twists and the twist angle can be adjusted. The closer to the filament center axis O, the smaller the twist angle can be.

[0089] In this way, the filament 11 can be manufactured, wherein the matrix resin including the thermoplastic resin is impregnated in the fiber bundle 25, the first fiber bundle group 31 is arranged along the filament central axis O, and the second fiber bundle group 33 to which a twist is applied is arranged on the outer periphery thereof. In addition, when manufacturing the filament 11, both the first fiber bundle group 31 and the second fiber bundle group 33 may be twisted, and in this case, the twist angle of the first fiber bundle group 31 is made smaller than the twist angle of the second fiber bundle group 33.

[0090] The present invention is not limited to the above-mentioned embodiments. Combinations of the various structures of the embodiments and changes and applications made by technicians in this field based on the description in the specification and known technologies are also the expected contents of the present invention, and these are all included in the scope of protection required.

[0091] As described above, this specification discloses the following matters.

[0092] (1) A filament used as a raw material for forming a 3D printer, wherein a fiber bundle including continuous reinforcing fibers is impregnated with a matrix resin, wherein:

[0093] The fiber bundle comprises a first fiber bundle group and a second fiber bundle group,

[0094] The twist angle of the first fiber bundle group is smaller than the twist angle of the second fiber bundle group.

[0095] According to the filament, the fiber bundle containing the continuous reinforcing fiber comprises a first fiber bundle group and a second fiber bundle group, and the twist angle of the first fiber bundle group is smaller than the twist angle of the second fiber bundle group. Thus, the filament can have good flexibility and improve the tensile strength and bending rigidity by the first fiber bundle group.

[0096] (2) The filament according to (1), wherein

[0097] The first fiber bundle group is arranged along the central axis of the filament.

[0098] The second fiber bundle group is arranged radially outside the first fiber bundle group and is twisted around the first fiber bundle group.

[0099] According to this filament, the second fiber bundle group is arranged radially outside the first fiber bundle group arranged along the central axis of the filament and twisted around the first fiber bundle group. This can provide good flexibility and improve tensile strength and bending rigidity in a balanced manner in the radial direction.

[0100] (3) The filament according to (1) or (2), wherein

[0101] The orientation direction of the reinforcing fibers in the first fiber bundle group is aligned parallel to the filament axial direction.

[0102] According to this filament, good flexibility can be obtained, and the tensile strength and bending rigidity can be improved by the first fiber bundle group.

[0103] (4) The filament according to (2), wherein

[0104] The outer periphery of the second fiber bundle group is covered with the matrix resin.

[0105] According to the filament, the outer periphery of the second fiber bundle group is covered with the matrix resin. Therefore, it can have good flexibility, and the tensile strength and bending rigidity can be further improved by the first fiber bundle group, and further, the reinforcing fibers of the second fiber bundle group arranged outside the first fiber bundle group can be protected by the matrix resin.

[0106] (5) The filament according to (4), wherein

[0107] Spiral grooves or convex strips are formed on the outer peripheral surface along the axial direction of the filament.

[0108] According to this filament, since spiral grooves or convex stripes are formed on the outer peripheral surface along the axial direction of the filament, the surface area of ​​the outer peripheral surface can be increased, and the flexibility can be improved.

[0109] (6) The filament according to any one of (1) to (5), wherein

[0110] The aforementioned matrix resin is a thermoplastic resin or a thermosetting resin.

[0111] According to this filament, the filament having a matrix resin composed of a thermoplastic resin or a thermosetting resin can have good flexibility, and the tensile strength and bending rigidity can be improved by the first fiber bundle group.

[0112] (7) A method for producing a shaped object, wherein:

[0113] The filaments described in any one of (1) to (6) are thermally melted, and the thermally melted forming material is ejected to form a formed object by lamination.

[0114] According to the manufacturing method of the shaped object, the second fiber bundle group is twisted at a twist angle larger than that of the first fiber bundle group, so the flexibility of the second fiber bundle group is improved. Therefore, when printing the curvature portion, the filaments are easy to follow the curvature, and the shaping accuracy is improved. In addition, the fiber bundles of the first fiber bundle group are smoothly opened and evenly dispersed during the shaping, so the fusion of the fibers becomes good. Furthermore, the fiber bundles are easy to open, so it is difficult for adjacent filaments to have gaps between each other when viewed from above, and they are easy to gather. As a result, a shaped object with excellent strength characteristics can be obtained.

[0115] In addition, the present application is based on the Japanese patent application (Japanese Patent Application No. 2022-088614) filed on May 31, 2022, the contents of which are incorporated herein by reference.

[0116] Description of Reference Numerals

[0117] 11, 11A, 11B, 11C filaments

[0118] 13 Filament feeding section

[0119] 15 Head

[0120] 15a Nozzle

[0121] 17 Workbench

[0122] 19 Forming drive unit

[0123] 21 Control Department

[0124] 23 Reinforced Fiber

[0125] 25 Fiber bundle

[0126] 27 Base resin

[0127] 31. First fiber bundle group

[0128] 33 Second fiber bundle group

[0129] 35 Resin

[0130] 37 slots

[0131] 41 Complex

[0132] 100-layer 3D printer

[0133] 200 filament manufacturing device.

Claims

1. A filament used as a raw material for forming a 3D printer, wherein a matrix resin is impregnated into a fiber bundle containing continuous reinforcing fibers, The fiber bundle comprises a first fiber bundle group and a second fiber bundle group, The twist angle of the first fiber bundle group is smaller than the twist angle of the second fiber bundle group.

2. The filament according to claim 1, characterized in that The first fiber bundle group is arranged along the central axis of the filament. The second fiber bundle group is arranged radially outside the first fiber bundle group and is twisted around the first fiber bundle group.

3. The filament according to claim 1, characterized in that The orientation direction of the reinforcing fibers in the first fiber bundle group is aligned parallel to the filament axial direction.

4. The filament according to claim 2, characterized in that The orientation direction of the reinforcing fibers in the first fiber bundle group is aligned parallel to the filament axial direction.

5. The filament according to claim 2, characterized in that The outer periphery of the second fiber bundle group is covered with the matrix resin.

6. The filament according to claim 5, characterized in that Spiral grooves or convex strips are formed on the outer peripheral surface along the axial direction of the filament.

7. The filament according to any one of claims 1 to 6, characterized in that The aforementioned matrix resin is a thermoplastic resin or a thermosetting resin.

8. A method for manufacturing a shaped object, characterized in that: The filaments according to any one of claims 1 to 6 are thermally melted, and the thermally melted forming material is ejected to form a formed object in layers.

9. A method for manufacturing a shaped object, characterized in that: The filaments according to claim 7 are heat-fused, and the heat-fused forming material is ejected to form a formed object in layers.

10. The method for manufacturing a shaped object according to claim 8, wherein: The filaments are heat-fused, and the heat-fused forming material is ejected to form a formed object in layers.

11. The method for manufacturing a shaped object according to claim 9, wherein: The filaments are heat-fused, and the heat-fused forming material is ejected to form a formed object in layers.

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