Additive manufacturing method, additive manufacturing equipment, and program

Abstract

To provide an additive manufacturing method, an additive manufacturing equipment, and a program, which can manufacture an object without causing a decrease in mechanical strength between lines and between layers of a modeling path.SOLUTION: There is provided an additive manufacturing method in which a modeling material made of continuous fiber-reinforced filament is modeled into a curved shape or a bent shape on a modeling surface, wherein a continuous fiber-reinforced resin filament 11 comprises: a base material containing a thermoplastic resin; and at least one fiber bundle 23 including continuous fibers impregnated in the base material and extending in an axial direction. Twisting of 20 times / m to 100 times / m centered around an axis of the continuous fiber-reinforced resin filament 11 is imparted to the continuous fibers of the fiber bundle 23. When the fiber bundle is Z-twisted, a modeling path on the modeling surface is a path that ejects the modeling material while being curved or bent to right toward a front in the modeling direction; when the fiber bundle is S-twisted, the modeling path is a path that ejects the modeling material while being curved or bent to left toward a front in the modeling direction, thereby modeling a curved shape or a bent shape.SELECTED DRAWING: Figure 4B

Description

[Technical field]

[0001] The present invention relates to an additive manufacturing method, an additive manufacturing apparatus, and a program. [Background technology]

[0002] As an additive manufacturing device that molds objects with three-dimensional shapes, a 3D (three-dimensional) printer that uses a fused deposition modeling method in which resin in a plasticized state by heat is stacked layer by layer along a modeling path is known. This 3D printer can mold three-dimensional shapes without requiring molds or jigs. In addition, it can even mold objects with three-dimensional shapes that are difficult to form using conventional injection molding technology.

[0003] For example, the strand described in Patent Document 1 is a filament used as a modeling material for a 3D printer, in which fibers or fiber bundles are impregnated and twisted in a base material mainly composed of a thermoplastic resin. This increases the flexibility of the filament itself, improving its ease of handling. In addition, because the fibers or fiber bundles in the filament are twisted, a model created by a 3D printer using the filament has excellent impact strength. In this way, the above-mentioned filament makes it possible to easily create a model with excellent impact strength using a 3D printer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-123026 Summary of the Invention [Problem to be solved by the invention]

[0005] However, it was found that a filament reinforced with continuous fibers having a twist rate of 10 times / m to 200 times / m as shown in Patent Document 1 may have a risk of the spread width of the reinforcing fibers decreasing or becoming unstable when a modeling material obtained by heating and melting the filament is discharged along a modeling path from a nozzle (discharge part) provided in the head part of a 3D printer. This problem was particularly noticeable in certain shapes of modeling paths when the twist rate given to the reinforcing fibers was large.

[0006] If the reinforcing fibers are not sufficiently spread, the fusion of the molding materials discharged from the nozzle between adjacent modeling passes is reduced, and voids are likely to be generated. This reduces the mechanical strength between the lines and layers of the modeling passes, which requires time and effort to change the modeling plan so that such a reduction in mechanical strength does not occur.

[0007] Therefore, an object of the present invention is to provide an additive manufacturing method, an additive manufacturing device, and a program that can manufacture an object without causing a decrease in mechanical strength between lines and layers of a modeling pass. [Means for solving the problem]

[0008] The present invention comprises the following configurations. (1) A layered manufacturing method in which a modeling material obtained by heating and melting a linear continuous fiber reinforced filament is ejected from a nozzle along a modeling path on a modeling surface to model a curved or bent shape on the modeling surface, The continuous fiber reinforced filament includes a substrate including a thermoplastic resin and at least one fiber bundle including continuous fibers impregnated in the substrate and extending in an axial direction; The continuous fibers of the fiber bundle are twisted about an axial core of the continuous fiber reinforced filament at 20 turns / m or more and 100 turns / m or less, When the fiber bundle is Z-twisted, the shaping path on the shaping surface is a path for discharging the shaping material while curving or bending it to the right side toward the front of the shaping direction, and when the fiber bundle is S-twisted, the shaping path is a path for discharging the shaping material while curving or bending it to the left side toward the front of the shaping direction, thereby forming the curved or bent shape. Additive manufacturing methods. (2) An additive manufacturing device comprising: a head unit that ejects a molding material obtained by heating and melting a linear continuous fiber reinforced filament from a nozzle; a drive mechanism that moves the nozzle of the head unit relative to a modeling surface; and a control unit that drives the drive mechanism to eject the molding material along a set modeling path, The continuous fiber reinforced filament includes a substrate including a thermoplastic resin and at least one fiber bundle including continuous fibers impregnated in the substrate and extending in an axial direction; The continuous fibers of the fiber bundle are twisted about an axial core of the continuous fiber reinforced filament at 20 turns / m or more and 100 turns / m or less, When a curved or bent shape is formed on the modeling surface, the control unit sets the modeling path on the modeling surface to a path in which the modeling material is discharged while curving or bending the fiber bundle to the right side toward the front of the modeling direction when the fiber bundle is Z-twisted, and sets the modeling path to a path in which the modeling material is discharged while curving or bending the fiber bundle to the left side toward the front of the modeling direction when the fiber bundle is S-twisted, thereby forming the curved or bent shape. Additive manufacturing equipment. (3) A program for executing an additive manufacturing procedure in which a modeling material obtained by heating and melting a linear continuous fiber reinforced filament is ejected from a nozzle along a modeling path on a modeling surface to model a curved or bent shape on the modeling surface, The continuous fiber reinforced filament includes a substrate including a thermoplastic resin and at least one fiber bundle including continuous fibers impregnated in the substrate and extending in an axial direction; The continuous fibers of the fiber bundle are twisted about an axial core of the continuous fiber reinforced filament at 20 turns / m or more and 100 turns / m or less, On the computer, When the fiber bundle is Z-twisted, the modeling path on the modeling surface is a path for discharging the modeling material while curving or bending it to the right side toward the front of the modeling direction, and when the fiber bundle is S-twisted, the modeling path is a path for discharging the modeling material while curving or bending it to the left side toward the front of the modeling direction, thereby executing a procedure for modeling the curved shape or the bent shape. program. Effect of the Invention

[0009] According to the present invention, a model can be layered and manufactured without causing a decrease in mechanical strength between lines and layers of a modeling pass. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram of an FDM-type additive manufacturing device. [Figure 2A] FIG. 2A is a schematic cross-sectional view of a radial direction perpendicular to the axial direction of the filament. [Figure 2B] FIG. 2B is a side view taken along the axial direction of the filament. [Diagram 3] FIG. 3 is a schematic diagram of a filament manufacturing apparatus. [Figure 4A] FIG. 4A is a diagram illustrating the state in which a modeling material formed by dissolving a filament is ejected onto a modeling surface from a nozzle (not shown), and is an explanatory diagram illustrating a vertical cross section of the filament. [Figure 4B] FIG. 4B is a schematic diagram showing how a modeling material made of molten filaments is ejected onto a modeling surface from a nozzle (not shown), and is a schematic plan view showing a partial cross section of FIG. 4A when viewed from above. [Diagram 5] FIG. 5 is an explanatory diagram that shows a schematic diagram of the twist direction when the reinforcing fibers of the fiber bundles in the filament are Z-twisted. [Figure 6] FIG. 6 is an explanatory diagram that shows a schematic diagram of the twist direction when the reinforcing fibers of the fiber bundles in the filament are S-twisted. [Figure 7]FIG. 7 is an explanatory diagram showing the direction in which the Z-twisted reinforcing fibers of the fiber bundle in the molding material rotate in position as the filament is fed at the same nozzle position. [Figure 8] FIG. 8 is an explanatory diagram showing the direction in which the arrangement position of the S-twisted reinforcing fibers in the fiber bundle in the shaping material rotates as the filament is fed at the same nozzle position. [Figure 9] FIG. 9 is an explanatory diagram showing the case where the reinforcing fibers are Z-twisted and the movement direction of the head unit is a clockwise modeling pass and a counterclockwise modeling pass. [Figure 10] FIG. 10 is an explanatory diagram showing the case where the reinforcing fibers are S-twisted and the movement direction of the head part is a clockwise modeling pass and a counterclockwise modeling pass. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. First, a configuration of a 3D printer, which is an additive manufacturing device, will be briefly described. Here, a configuration of an FDM (Fused Deposition Modeling) system is illustrated, but the present invention is not limited to this and may be configured in other systems.

[0012] <Configuration of additive manufacturing device> 1 is a schematic diagram of an FDM-type additive manufacturing apparatus 100. The additive manufacturing apparatus 100 includes a filament feeder 13 that feeds a continuous fiber reinforced resin filament 11 (hereinafter also referred to as a filament), a head unit 15, a table 17, a molding driver 19, and a controller 21.

[0013] The filament feeding unit 13 includes a pair of drive rollers 13a that sandwich the filament 11, and a driving unit (not shown) such as a motor that rotates and drives at least one of the drive rollers 13a. The head unit 15 includes a heating unit (not shown) that thermally melts the fed filament 11, and a nozzle 15a that ejects the molding material melted by the heating unit. Although not shown, the head unit 15 may also be provided with a cutting unit such as a cutter or laser cutting device that cuts reinforcing fibers contained in the filament 11.

[0014] The table 17 is disposed opposite the nozzle 15a of the head unit 15 and has a modeling surface 17a on which a model is stacked. The forming drive unit 19 moves the head unit 15 and the table 17 relative to each other to form the modeling material discharged from the nozzle 15a of the head unit 15 along a desired path. The table 17 driven by the forming drive unit 19 may be configured to include, for example, a two-axis drive mechanism that moves the head unit 15 within the plane of the modeling surface 17a of the table 17, and a lifting mechanism that drives the table 17 up and down to adjust the stacking height. In this configuration, the table 17 and the forming drive unit 19 function as a drive mechanism that moves the nozzle 15a of the head unit 15 relative to the modeling surface 17a. The drive mechanism may be a mechanism that moves the head unit 15 with the table 17 as a fixed side, or a mechanism that operates both the table 17 and the head unit 15.

[0015] The control unit 21 has a function of controlling the feeding of the filament 11 by the filament feeding unit 13 and the relative movement of the head unit 15 by the drive mechanism, and a function of overall control of each of the other units. A modeling program that controls each unit including the filament feeding unit 13 and the molding drive unit 19 is input to the control unit 21, and the input modeling program is executed by the control unit 21 to layer-model an object of a desired shape.

[0016] The control unit 21 is configured by hardware using an information processing device such as a PC (Personal Computer). Each function of the control unit 21 is realized by a control device such as a processor such as a CPU (Central Processing Unit) or an MPU (Micro Processor Unit), or a dedicated circuit, reading and executing a program having a specific function stored in a storage device (not shown). Examples of the storage device include a memory such as a RAM (Random Access Memory) which is a volatile storage area, a ROM (Read Only Memory) which is a non-volatile storage area, and a storage such as a HDD (Hard Disk Drive) or an SSD (Solid State Drive). In addition to the above-mentioned forms, the control unit 21 may be another computer remotely connected to the additive manufacturing apparatus 100 via a network or the like.

[0017] <Manufacturing method for molded objects> In the additive manufacturing apparatus 100 of this configuration, the control unit 21 outputs a drive signal to the filament feeding unit 13, which causes the filament feeding unit 13 to rotate the drive roller 13a and feed the filament 11 to the head unit 15 at a specified feeding speed. The head unit 15 heats the fed filament 11 to thermally melt it. Then, the control unit 21 outputs a drive signal to the molding drive unit 19, which causes the modeling material melted in the head unit 15 to be ejected from the nozzle 15a while moving the head unit 15 and the table 17 relative to each other.

[0018] In the present configuration, when the head unit 15 is fixed and the table 17 is movable, the nozzle 15a of the head unit 15 is driven to move relative to the table 17 along a modeling path created according to the shape of the object. As a result, a new modeling material is ejected from the nozzle 15a along the modeling path and layered on the modeling surface 17a of the table 17 or on the modeling material of the previous layer (existing layer). In this way, a modeling object of a desired shape is formed. The modeling program includes information on the modeling path described above, information on various modeling conditions required for modeling, such as the feed speed of the filament 11, and the like. The control unit 21 reads the information on these modeling conditions from the modeling program described above, and layers the modeling material in a specified procedure to form the object.

[0019] <Filament composition> Next, the configuration of the filament 11 used in the layered modeling apparatus 100 will be described. Fig. 2A is a schematic cross-sectional view in a radial direction perpendicular to the axial direction of the filament 11. Fig. 2B is a side view along the axial direction of the filament 11. In the following description, the same members or parts are denoted by the same reference numerals to simplify or omit the description thereof.

[0020] As shown in FIG. 2A and FIG. 2B, the filament 11 is a linear resin material used as a modeling raw material for a 3D printer such as the above-mentioned additive manufacturing device 100. In the filament 11, a thermoplastic matrix resin 25 is impregnated into a fiber bundle 23 including continuous fibers (hereinafter also referred to as "reinforcing fibers"). Furthermore, a matrix resin 27 is formed with a predetermined thickness on the radial outside of the fiber bundle 23 so as to cover the fiber bundle 23. These matrix resins 25, 27 (hereinafter also referred to as "resin") serve as the base material of the filament 11. The matrix resins 25, 27 may be thermoplastic resins, other resin materials such as thermosetting resins and photocurable resins, or materials obtained by kneading a plurality of materials. The fiber bundles 23 in the filament 11 are arranged along the filament central axis O, and are twisted around the filament central axis O.

[0021] The diameter of the filament 11 is preferably, for example, 0.5 mm or more and 1 mm or less, and the smaller the diameter, the more accurately the fine shape of the shaped object can be reproduced. Also, the fiber bundle 23 preferably contains 1,500 or more and 6,000 or less continuous fibers. In this case, the continuous fibers are arranged at a high density in the shaped object, and the strength of the shaped object can be sufficiently improved. However, the above numerical ranges are merely examples and are not intended to be limiting.

[0022] When the number of twists of the continuous fibers of the fiber bundle 23 is 20 times / m or more and 100 times / m or less along the axial direction of the filaments 11, the effect of increasing stable fiber spreading and the effect of improving the molding accuracy are exhibited when molding in the molding direction described in detail later. The number of twists is more preferably 25 times / m or more, and even more preferably 30 times / m or more. Moreover, the number of twists is more preferably 80 times / m or less, and even more preferably 70 times / m or less.

[0023] The reinforcing fibers constituting the fiber bundle 23 can be organic fibers such as polyethylene fibers, aramid fibers, and Zylon fibers, and inorganic fibers such as boron fibers, glass fibers, carbon fibers, metal fibers, and rock fibers. Surface-treated fibers can be used as the reinforcing fibers to improve the adhesive strength between the resin and the fibers.

[0024] The fiber bundle 23 may be formed of a single bundle as shown in FIG. 2A, but may also be an assembly of multiple fiber bundles, in which case the reinforcing fibers of each fiber bundle may be twisted together or each fiber bundle may be twisted individually.

[0025] Examples of materials for the matrix resins 25, 27 when the main component is a thermoplastic resin include polyolefin resins such as polypropylene or polyethylene, acrylonitrile-butadiene-styrene resin, polystyrene resin, polyester resins such as polyethylene terephthalate, polybutylene terephthalate, or polylactic acid, polyamide resins, aromatic polyamide resins, polyetherimide, polyarylimide, polyarylate, polyether ether ketone, polyaryl ether ketone, polybenzimidazole, polyethersulfone, polysulfone, polyvinylidene fluoride resin, liquid crystal polymer, polycarbonate resin, polyacetal, or polyphenylene sulfide.

[0026] These thermoplastic resins may be used alone, or may be blended with a plurality of resins to improve the heat resistance, heat distortion temperature, heat aging, tensile properties, bending properties, creep properties, compression properties, fatigue properties, impact properties, and sliding properties of the thermoplastic resin. Examples of the thermoplastic resin include polyether ether ketone resin (PEEK) / polytetrafluoroethylene (PTFE), PEEK / polybenzimidazole (PBI), etc. The thermoplastic resin may also be one to which short fibers such as carbon fibers and glass fibers, talc, etc. are added.

[0027] In addition, the durability of the molded object may be improved by adding to the thermoplastic resin antioxidants such as phenols, thioethers, and phosphites, ultraviolet absorbers such as benzotriazoles or triazines, and metal deactivators such as hydrazides or amides.

[0028] Adding a plasticizer such as a phthalic acid-based or polyester-based plasticizer to a thermoplastic resin improves the resin's flexibility, thereby improving the molding accuracy during molding and the flexibility of the molded object.

[0029] The flame retardancy of the molded object can be improved by adding halogen-based, phosphate-based, inorganic, or intumescent flame retardants to thermoplastic resins.

[0030] Adding a core material such as a phosphate metal salt or sorbitol to a thermoplastic resin can control thermal expansion during molding, improving molding accuracy.

[0031] The addition of a permanent antistatic agent such as a nonionic, anionic, or cationic agent to a thermoplastic resin can improve the antistatic properties of the molded object.

[0032] By adding a lubricant such as a hydrocarbon-based or metal soap-based lubricant to the thermoplastic resin to improve the lubricity of the continuous fiber reinforced filament, the filament can be smoothly fed out during molding.

[0033] <Filament manufacturing method> The filament 11 used in the above-mentioned 3D printer is formed by twisting the reinforcing fibers of the fiber bundle 23, and the orientation angle of the reinforcing fibers is inclined with respect to the axial direction. An example of a method for producing such a filament 11 will be described. Note that the configuration of the filament production device shown here is one example, and is not limited to this.

[0034] FIG. 3 is a schematic diagram of the filament manufacturing apparatus 200. The filament manufacturing apparatus 200 includes a fiber material supply section 31, a kneading extruder 33, a resin bath section 35, a cooling section 37, and a twisting section 39. The fiber material supply section 31 delivers one or more fiber bundles 23 wound in a coil shape at a predetermined speed. The kneading extruder 33 is provided with a screw shaft (not shown) having kneading blades rotatably in a hollow chamber 33a, and melts and plasticizes the resin fed from a hopper 33b. The resin bath section 35 impregnates the fiber bundle 23 delivered from the fiber material supply section 31 with the resin plasticized by the kneading extruder 33. The cooling section 37 is disposed downstream of the resin bath section 35, and cools the composite 41 delivered from the resin bath section 35. The twisting section 39 mainly imparts twisting about the axial center to the fiber bundle 23 before cooling.

[0035] The resin bath section 35 is formed in a cylindrical shape with the cylinder axis oriented vertically. Resin 43 plasticized by the kneading extruder 33 is supplied and stored inside the cylinder. The upper end of the resin bath section 35 is open, and the fiber bundle 23 guided by a guide roller 45 is drawn into the resin 43 stored in the resin bath section 35 from the opening at the upper end.

[0036] A plurality of impregnation rolls (not shown) are provided inside the resin bath section 35 and are rotatably held with their axes oriented horizontally. The fiber bundle 23 introduced from an opening at the upper end of the resin bath section 35 is passed over each of the impregnation rolls in order and sent to an outlet section 47 arranged at the lower end of the resin bath section 35. A die 49 is provided at the outlet section 47 for shaping the outer periphery of the filament 11 when the composite 41 of the resin 43 and the fiber bundle 23 is drawn out of the resin bath section 35. The die 49 can form irregularities such as grooves and ridges on the outer periphery of the filament 11 depending on the shape of its opening.

[0037] The cooling section 37 is an elongated water tank arranged along the direction in which the composite 41 is drawn out from the resin bath section 35, and stores cooling water 51 in the tank. In the cooling section 37, the resin impregnated in the fiber bundles 23 of the composite 41 is cooled in the cooling water 51 and hardened.

[0038] The twisting section 39 is disposed downstream of the cooling section 37 and has a pair of upper and lower take-up rolls 53, 55 whose outer circumferential surfaces are in contact with each other. The twisting section 39 can employ various mechanisms in addition to a configuration including the take-up rolls 53, 55. For example, although not shown, it may be a mechanism in which a bobbin that winds the filament 11 rotates around the axis of the filament 11.

[0039] The take-up rolls 53, 55 have the function of drawing in the fiber bundle 23 from the fiber material supply section 31 to the resin bath section 35, and further drawing out the composite 41 from the resin bath section 35 to the cooling section 37 and the twisting section 39. A separate winding section (not shown) such as a bobbin is provided downstream of the twisting section 39 to wind up the manufactured filament 11.

[0040] The procedure for producing the filament 11 using the above-described filament production apparatus 200 is as follows. (Impregnation process) The impregnation process is carried out in the resin bath section 35 of the filament manufacturing apparatus 200. Specifically, the resin supplied from the hopper 33b is kneaded in the kneading extruder 33, and the molten resin is stored in the resin bath section 35. The fiber bundle 23 is supplied from the fiber material supply section 31 to this resin bath section 35. Then, the fiber bundle 23 impregnated with the molten resin in the resin bath section 35 is passed through a die 49 disposed in the outlet section 47 to adjust the amount of resin impregnation. This resin impregnation results in a state in which the matrix resin is present in the gaps in the fiber bundle 23 and around the radial outer periphery of the fiber bundle 23. The composite 41 of the matrix resin and the fiber bundle 23 obtained in this manner is cooled in the cooling section 37.

[0041] (Twisting process) In the twisting process, the twisting unit 39 twists the fiber bundle 23 impregnated with the resin in the resin bath unit 35. Specifically, while rotating the take-up rolls 53, 55 of the twisting unit 39, the composite 41 that has passed through the cooling unit 37 is passed between the take-up rolls 53, 55. This imparts a twist to the continuous fibers of the fiber bundle 23. The number of twists and the twist angle can be adjusted by adjusting the inclination angle of the take-up rolls 53, 55 with respect to the take-up direction.

[0042] In this manner, the matrix resin 25 containing a thermoplastic resin is impregnated into the fiber bundles 23 arranged along the filament central axis O, and the filament 11 can be manufactured in which the matrix resin 27 is formed on the outer periphery of the fiber bundles 23 on the radially outer side so as to cover the fiber bundles 23. When manufacturing the filament 11, each of the fiber bundles supplied from the multiple fiber material supply units 31 may be twisted individually, or each fiber bundle may be twisted collectively.

[0043] <Spread state of fiber bundles during molding> When forming a structure by the fused deposition modeling method using the above-mentioned filament 11, if the number of twists imparted to the reinforcing fibers of the fiber bundle 23 is large, the spread width of the fiber bundle 23 discharged from the nozzle 15a is likely to decrease or become unstable depending on the shape of the forming pass.

[0044] 4A and 4B are schematic diagrams showing how a molding material formed by melting a filament 11 is discharged onto a printing surface from a nozzle (not shown), where Fig. 4A is an explanatory diagram showing a vertical cross section of the filament 11, and Fig. 4B is a schematic plan view showing a partial cross section when Fig. 4A is viewed in plan. As shown in Fig. 4A, the filament 11 is fed and supplied in the vertical direction, and the melted molding material is discharged onto the printing surface 17a along the printing direction WD. As shown in Fig. 4B, the fiber bundles 23 in the molding material are spread to a width W wider than the width W0 of the filament 11 before it is melted.

[0045] If the number of twists in the reinforcing fibers of the fiber bundle 23 is large, the fibers may not be fully opened even after the molding material is discharged. In such a case, the fusion between the molding material and the molding surface 17a of the table 17 shown in Fig. 1 or the base may be incomplete, or the reinforcing fibers may be unevenly dispersed during molding, affecting the strength of the molded object. Therefore, during molding, it is preferable to discharge the molding material while untwisting the fiber bundle 23.

[0046] The spread state of the fiber bundle 23 changes depending on the number of twists of the reinforcing fibers of the original fiber bundle 23 and the direction of the shaping pass (shaping direction). Generally, Z twist and S twist are known as the twist direction.

[0047] Fig. 5 is an explanatory diagram showing a typical twist direction when the reinforcing fibers of the fiber bundle 23 in the filament 11 are Z-twisted. Fig. 6 is an explanatory diagram showing a typical twist direction when the reinforcing fibers of the fiber bundle 23 in the filament 11 are S-twisted. Figs. 5 and 6 show three long fibers twisted in a spiral shape along the central axis O of the filament together with layers L1 to L6 of each cross section along the longitudinal direction of the filament 11 (fiber bundle 23).

[0048] In the case of Z twist shown in FIG. 5, the vertical downward direction is considered to be the discharge side from the nozzle 15a (FIG. 1) which is the front of the filament feed direction FD. In this case, when the filament 11 is fed to the nozzle 15a, the reinforcing fiber passing the position of the nozzle 15a rotates counterclockwise. In other words, as the filament 11 is fed to the nozzle 15a, the layers L1 to L6 of the filament 11 are sequentially arranged at the discharge position from the nozzle 15a. In this case, when focusing on a specific fiber F, the position of the fiber F moves counterclockwise from the position of the fiber F in the layer L1 when the layer L2 reaches the position of the nozzle 15a as the filament 11 is fed. Then, when the feeding of the filament 11 proceeds to the layers L3 to L6, the arrangement of the fiber F in each layer rotates counterclockwise around the central axis O of the filament.

[0049] Similarly, in the case of the S twist shown in FIG. 6, the arrangement of the fibers F in each layer rotates clockwise around the central axis O of the filament as the filament 11 is fed.

[0050] Fig. 7 is an explanatory diagram showing the direction in which the arrangement position of the Z-twisted reinforcing fibers of the fiber bundle 23 in the shaping material at the same nozzle position rotates as the filament 11 is fed. Fig. 8 is an explanatory diagram showing the direction in which the arrangement position of the S-twisted reinforcing fibers of the fiber bundle 23 in the shaping material at the same nozzle position rotates as the filament 11 is fed.

[0051] As shown in Fig. 7, when the reinforcing fibers of the fiber bundle 23 are Z-twisted, the twisted reinforcing fibers are continuously supplied at the nozzle 15a while rotating counterclockwise in association with the feeding of the filament 11. As shown in Fig. 8, when the reinforcing fibers of the fiber bundle 23 are S-twisted, the twisted reinforcing fibers are continuously supplied at the nozzle 15a while rotating clockwise in association with the feeding of the filament 11.

[0052] The reinforcing fibers twisted as described above are supplied from the nozzle 15a while rotating during modeling. Next, the relationship between the rotation direction (twist direction) of the reinforcing fibers and the modeling direction WD will be described. FIG. 9 is an explanatory diagram showing the case where the movement direction of the head unit 15 is clockwise (curved to the right) in the case of the shaping pass PS_R and counterclockwise (curved to the left) in the case of the shaping pass PS_L when the reinforcing fibers are Z-twisted. In the case of Z-twist, the shaping direction of the shaping pass PS_L is curved in the same direction as the twist direction of the reinforcing fibers (counterclockwise), so the twist of the reinforcing fibers is difficult to untwist, and therefore the fibers are difficult to open. On the other hand, the shaping direction of the shaping pass PS_R is curved in the opposite direction to the twist direction of the reinforcing fibers (counterclockwise), so the twist of the reinforcing fibers is easily untwisted. Therefore, in the case of Z-twist, if the shaping direction is set to the direction of the shaping pass PS_R, it is easy to obtain a good opened state as shown in FIG. 4B.

[0053] FIG. 10 is an explanatory diagram showing the case where the movement direction of the head unit 15 is clockwise (curved to the right) in the case of the shaping pass PS_R and counterclockwise (curved to the left) in the case of the shaping pass PS_L when the reinforcing fibers are S-twisted. In the case of S-twist, the shaping direction of the shaping pass PS_R curves in the same direction as the twist direction of the reinforcing fibers (clockwise), so the twist of the reinforcing fibers is difficult to untwist, and therefore the fibers are difficult to open. On the other hand, the shaping direction of the shaping pass PS_L curves in the opposite direction to the twist direction of the reinforcing fibers (clockwise), so the twist of the reinforcing fibers is easily untwisted. Therefore, in the case of S-twist, if the shaping direction is in the direction of the shaping pass PS_L, it is easy to obtain a good opened state as shown in FIG. 4B.

[0054] The radius of curvature of the curved shaping path referred to here is preferably set to be larger than the width W0 (FIG. 4B) of the shaping material so that the shaping materials ejected from the nozzle 15a do not overlap each other. For example, the radius of curvature of the curved shaping path is preferably 1.5 mm or more, more preferably 2 mm or more, and even more preferably 2.5 mm or more. The upper limit of the radius of curvature may be any value that does not cause overlap of the shaping materials. In this specification, "curve" is expressed as "bend" when the length of the curved portion of the shaping path is extremely short, but the preferred shaping direction is the same in either case.

[0055] In other words, when forming a curved or bent shape on the printing surface 17a, the control unit 21 forms a curved or bent shape by setting a printing pass in which the fiber bundle 23 is curved or bent to the left toward the front in the printing direction on the printing surface 17a when the fiber bundle 23 is Z-twisted, and by setting a printing pass in which the fiber bundle 23 is curved or bent to the right toward the front in the printing direction when the fiber bundle 23 is S-twisted, thereby forming a curved or bent shape. The above-mentioned printing passes may be set by the control unit 21 according to the filament 11 used, or the printing program may be set to switch depending on the filament 11 used.

[0056] For example, whether the filament 11 used in the additive manufacturing apparatus 100 is Z-twisted or S-twisted is determined by an operator or automatically determined by a sensor or the like. The determination result is input to the control unit 21. The control unit 21 sets a modeling path with a preferred modeling direction according to the determination result. Specifically, a modeling path for Z-twist and a modeling path for S-twist may be prepared in the modeling program, and the control unit 21 may selectively use one of the modeling paths to perform modeling. EXAMPLES

[0057] Here, several types of filaments with different configurations were used, and each was molded along a curved printing path that was curved in the same direction as the twist direction of the reinforcing fibers in the fiber bundle, and in the opposite direction. The spread width of the reinforcing fibers in the linearly formed molding material and the circularity of the circular object created by the circular printing path were evaluated. The configuration of each filament and the evaluation results are summarized in Table 1.

[0058] [Table 1]

[0059] In test examples A1, A2, and B1, UBE Nylon (registered trademark) 1010X1 (manufactured by UBE Corporation) was used as the thermoplastic resin, and a fiber bundle consisting of 1,500 TAIRYFIL TC-33 (manufactured by FORMOSA PLASTICS CORPORATION) fibers was used as the reinforcing fiber to produce a fiber-reinforced resin filament (cross-sectional diameter 0.5 mm) with a fiber content of 40 mass%.

[0060] For the production of fiber-reinforced resin filaments, a filament production apparatus 200 as shown in Fig. 1 was used. A fiber material was impregnated into a molten thermoplastic resin, and the twist angle θ (see Fig. 1) and the number of twists N per meter of the composite 41 were set by adjusting the inclination angle of the composite 41 with respect to the take-up direction of a pair of take-up rolls 53, 55 of the twisting section 39.

[0061] In Test Example A1, the twist angle θ was 3° and the number of twists N was 33 turns / m, in Test Example A2, the twist angle θ was 7° and the number of twists N was 78 turns / m, and in Test Example B1, the twist angle θ was 10° and the number of twists N was 112 turns / m. In this manner, the filaments of Test Examples A1, A2, and B1 were formed.

[0062] In test examples A3, A4 and B2, the same thermoplastic resin as in test examples A1, A2 and B1 and filament manufacturing apparatus 200 were used, and a fiber bundle consisting of 3,000 Pyrofil (registered trademark) TR30S 3L (manufactured by Mitsubishi Chemical Corporation) fibers was used as the reinforcing fiber to produce a fiber-reinforced resin filament (cross-sectional diameter 0.7 mm) with a fiber content of 40 mass%.

[0063] In addition, the inclination angle of the pair of take-up rolls 53, 55 with respect to the take-up direction was adjusted to set the twist angle θ and the number of twists N in the composite 41, respectively. In Test Example A3, the twist angle θ was 3° and the number of twists N was 24 times / m, in Test Example A4, the twist angle θ was 7° and the number of twists N was 56 times / m, and in Test Example B2, the twist angle θ was 13° and the number of twists N was 105 times / m. In this manner, the filaments of Test Examples A3, A4, and B2 were formed.

[0064] In test examples A5, A6 and B3, the same thermoplastic resin as in test examples A1, A2 and B1 and filament manufacturing apparatus 200 were used, and a fiber bundle consisting of 6,000 Pyrofil (registered trademark) TR50S 6L (manufactured by Mitsubishi Chemical Corporation) fibers was used as the reinforcing fiber to produce a fiber-reinforced resin filament (cross-sectional diameter 1 mm) with a fiber content of 40 mass%.

[0065] Similarly, the twist angle θ and the number of twists N in the composite 41 were set as described above. In the test example A5, the twist angle θ was 6° and the number of twists N per meter was 33 / m, in the test example A6, the twist angle θ was 10° and the number of twists N per meter was 56 / m, and in the test example B3, the twist angle θ was 20° and the number of twists N was 116 / m. In this manner, the filaments of the test examples A5, A6, and B3 were formed.

[0066] (Evaluation of fiber opening) The obtained filaments were used as filaments for a 3D printer as shown in Figure 1, and a one-layer model was obtained under the conditions of a nozzle temperature of 260 °C, a table temperature of 60 °C, and a printing speed of 5 mm / sec. This modeling was carried out based on a circular curved modeling model (modeling path) with a radius of 5 mm. The spread width of the reinforcing fibers was measured from the captured image of a circular model formed on the modeling surface, which was imaged with a laser microscope. Specifically, the radial width of the reinforcing fibers in the model was measured at multiple points along the circumferential direction of the model using image processing software, and the average value was taken as the spread width. The spread width was compared for each modeling direction (printing direction) along the modeling path curved clockwise or counterclockwise, and if an increase in the spread width was observed by setting the modeling direction to the untwisting direction of the reinforcing fibers, the directional advantage was indicated as "Yes", and if an increase in the spread width was not observed, the directional advantage was indicated as "No".

[0067] In addition, if the radius of curvature of the curved modeling pass is smaller than, for example, a radius of 2.5 mm, which is half the filament diameter, the radius of curvature of the modeling pass becomes too close to the spread width, causing the inner circumference of the modeled object to overlap, reducing the reproducibility of the shape of the set curved model. Therefore, this evaluation is limited to cases where the radius of curvature of the curved modeling pass (bending) is larger than the radius of the filament. In addition, the maximum possible width of the spread width corresponds to the total width of the modeling material on the modeling surface when the modeling material, which is the thermally melted matrix resins 25, 27 contained in the filament 11, is discharged from the nozzle 15a and spreads on the modeling surface in a direction perpendicular to the modeling direction.

[0068] (Evaluation of molding accuracy) For the objects evaluated for the above-mentioned fiber opening property, the circularity of the outer and inner circumferences of the circular shape was calculated using the above-mentioned laser microscope and image processing software, and the average value of the inner and outer circumferences was calculated. The calculated average circularity was compared between the cases where the modeling direction (printing direction) was curved clockwise and the case where the modeling direction was curved counterclockwise, and the modeling accuracy was evaluated based on the magnitude of deviation from the set circular orbit (circular modeling path). When the effect of improving modeling accuracy by setting the modeling direction to the untwisting direction of the reinforcing fibers was recognized, the directional advantage was indicated as "Yes", and when the effect of improving modeling accuracy was not recognized, the directional advantage was indicated as "No".

[0069] (Evaluation Results) As a result, in Test Examples A1 to A5 and Test Examples B1 to B3, the measurement results for the spread width in the molding direction curved in the untwisting direction were larger than the measurement results for the molding direction curved in the twist direction. Regarding the circularity, in Test Examples A1 to A5, the measurement results for the molding direction curved in the untwisting direction were larger than the measurement results for the molding direction curved in the twist direction. On the other hand, in Test Examples B1 to B3, the measurement results for the molding direction curved in the untwisting direction were smaller than the measurement results for the molding direction curved in the twist direction.

[0070] According to the above results, when a curved or bent shape is formed using a filament in which the reinforcing fibers of the fiber bundle are twisted 20 to 100 times per meter, as in Test Examples A1 to A6, the opening property can be improved without reducing the modeling accuracy by forming the filament along the direction of curvature or bending opposite to the twist direction of the reinforcing fibers of the fiber bundle. In other words, it was shown that the adhesion between the modeling materials formed by adjacent modeling passes is improved, and when the model has a multi-layer structure, the adhesion between the layers is also improved, making it possible to suppress a decrease in the strength of the modeled object while maintaining high shape accuracy.

[0071] The present invention is not limited to the above-described embodiments, and the present invention also contemplates the mutual combination of the various components of the embodiments, as well as modifications and applications by those skilled in the art based on the description in the specification and well-known techniques, and these are included in the scope of protection sought.

[0072] As described above, the present specification discloses the following: (1) A layered manufacturing method in which a modeling material obtained by heating and melting a linear continuous fiber reinforced filament is ejected from a nozzle along a modeling path on a modeling surface to model a curved or bent shape on the modeling surface, The continuous fiber reinforced filament includes a substrate including a thermoplastic resin and at least one fiber bundle including continuous fibers impregnated in the substrate and extending in an axial direction; The continuous fibers of the fiber bundle are twisted about an axial core of the continuous fiber reinforced filament at 20 turns / m or more and 100 turns / m or less, When the fiber bundle is Z-twisted, the shaping path on the shaping surface is a path for discharging the shaping material while curving or bending it to the right side toward the front of the shaping direction, and when the fiber bundle is S-twisted, the shaping path is a path for discharging the shaping material while curving or bending it to the left side toward the front of the shaping direction, thereby forming the curved or bent shape. Additive manufacturing methods. According to this additive manufacturing method, when a continuous fiber reinforced filament having a fiber bundle is molded using a molten molding material, the filament is molded in the opposite direction to the twist direction of the continuous fibers of the fiber bundle, thereby improving the spreadability without reducing the molding accuracy. This effect is particularly noticeable when the twist number of the continuous fibers is 20 times / m or more and 100 times / m or less. As a result, the adhesion between adjacent molding materials can be improved, and a decrease in the strength of the molded object can be suppressed.

[0073] (2) The additive manufacturing method described in (1), in which the radius of curvature of the curved or bent shape is greater than the width perpendicular to the manufacturing direction of the molding material ejected onto the manufacturing surface. According to this additive manufacturing method, the molding material ejected from the nozzle does not overlap, and high molding accuracy can be maintained.

[0074] (3) The additive manufacturing method according to (1) or (2), wherein the fiber bundle includes 1,500 or more and 6,000 or less continuous fibers. According to this additive manufacturing method, the continuous fibers are arranged at a high density in the object, thereby sufficiently improving the strength of the object.

[0075] (4) The additive manufacturing method according to any one of (1) to (3), wherein the diameter of the continuous fiber reinforced filament is 0.5 mm or more and 1 mm or less. This additive manufacturing method makes it possible to accurately reproduce the fine details of an object.

[0076] (5) An additive manufacturing device comprising: a head unit that ejects a molding material obtained by heating and melting a linear continuous fiber reinforced filament from a nozzle; a drive mechanism that moves the nozzle of the head unit relative to a modeling surface; and a control unit that drives the drive mechanism to eject the molding material along a set modeling path, The continuous fiber reinforced filament includes a substrate including a thermoplastic resin and at least one fiber bundle including continuous fibers impregnated in the substrate and extending in an axial direction; The continuous fibers of the fiber bundle are twisted about an axial core of the continuous fiber reinforced filament at 20 turns / m or more and 100 turns / m or less, The control unit of the additive manufacturing device, when forming a curved or bent shape on the manufacturing surface, sets the manufacturing path on the manufacturing surface to a path that ejects the manufacturing material while curving or bending the fiber bundle to the right toward the front in the manufacturing direction when the fiber bundle is Z-twisted, and sets the manufacturing path to a path that ejects the manufacturing material while curving or bending the fiber bundle to the left toward the front in the manufacturing direction when the fiber bundle is S-twisted, thereby forming the curved or bent shape. According to this additive manufacturing device, when a continuous fiber reinforced filament having a fiber bundle is molded using a molten molding material, the filament is molded in the opposite direction to the twist direction of the continuous fibers of the fiber bundle, thereby improving the spreadability without reducing the molding accuracy. This effect is particularly noticeable when the twist number of the continuous fibers is 20 times / m or more and 100 times / m or less. As a result, the adhesion between adjacent molding materials can be improved, and a decrease in the strength of the molded object can be suppressed.

[0077] (6) A program for executing an additive manufacturing procedure in which a modeling material obtained by heating and melting a linear continuous fiber reinforced filament is ejected from a nozzle along a modeling path on a modeling surface to model a curved or bent shape on the modeling surface, The continuous fiber reinforced filament includes a substrate including a thermoplastic resin and at least one fiber bundle including continuous fibers impregnated in the substrate and extending in an axial direction; The continuous fibers of the fiber bundle are twisted about an axial core of the continuous fiber reinforced filament at 20 turns / m or more and 100 turns / m or less, On the computer, A program that executes a procedure for forming the curved or bent shape by setting the printing path on the printing surface to a path that ejects the printing material while curving or bending the fiber bundle to the right toward the front in the printing direction when the fiber bundle is Z-twisted, and setting the printing path on the printing surface to a path that ejects the printing material while curving or bending the fiber bundle to the left toward the front in the printing direction when the fiber bundle is S-twisted. According to this program, when a continuous fiber reinforced filament having a fiber bundle is molded using a molten molding material, the filament is molded in the opposite direction to the twist direction of the continuous fibers of the fiber bundle, thereby improving the spreadability without reducing the molding accuracy. In particular, when the twist number of the continuous fibers is 20 times / m or more and 100 times / m or less, the effect is remarkable. As a result, the adhesion between adjacent molding materials can be improved, and a decrease in the strength of the molded object can be suppressed. [Explanation of symbols]

[0078] 11 Filament (continuous fiber reinforced plastic filament) 13 Filament feed section 13a Drive roller 15 Head section 15a Nozzle 17 Table 17a Modeling surface 19 Forming drive unit 21 Control section 23 Fiber bundle 25 Matrix Resin 27 Matrix Resin 31 Fiber Material Supply Section 33 Kneading extruder 33a Chamber 33b Hopper 35 Resin bath section 37 Cooling section 39 Twisting section 41 Complex 43 Resin 45 Guide roller 47 Exit section 49 Dice 51 Cooling water 53,55 Take-off roll 100 Additive manufacturing equipment 200 Filament manufacturing equipment

Claims

1. A layered manufacturing method in which a modeling material obtained by heating and melting a linear continuous fiber reinforced filament is discharged from a nozzle along a modeling path on a modeling surface to model a curved or bent shape on the modeling surface, The continuous fiber reinforced filament includes a substrate including a thermoplastic resin and at least one fiber bundle including continuous fibers impregnated in the substrate and extending in an axial direction; The continuous fibers of the fiber bundle are twisted about an axial core of the continuous fiber reinforced filament at 20 turns / m or more and 100 turns / m or less, When the fiber bundle is Z-twisted, the shaping path on the shaping surface is a path for discharging the shaping material while curving or bending it to the right side toward the front of the shaping direction, and when the fiber bundle is S-twisted, the shaping path is a path for discharging the shaping material while curving or bending it to the left side toward the front of the shaping direction, thereby forming the curved or bent shape. Additive manufacturing methods.

2. a radius of curvature of the curved or bent shape is greater than a width of the forming material discharged onto the forming surface in a direction perpendicular to the forming direction; The additive manufacturing method according to claim 1 .

3. The fiber bundle contains 1,500 or more and 6,000 or less continuous fibers. The additive manufacturing method according to claim 1 or 2.

4. The diameter of the continuous fiber reinforced filament is 0.5 mm or more and 1 mm or less. The additive manufacturing method according to claim 1 or 2.

5. An additive manufacturing device comprising: a head unit that ejects a molding material obtained by heating and melting a linear continuous fiber reinforced filament from a nozzle; a drive mechanism that moves the nozzle of the head unit relative to a modeling surface; and a control unit that drives the drive mechanism to eject the molding material along a set modeling path, The continuous fiber reinforced filament includes a substrate including a thermoplastic resin and at least one fiber bundle including continuous fibers impregnated in the substrate and extending in an axial direction; The continuous fibers of the fiber bundle are twisted about an axial core of the continuous fiber reinforced filament at 20 turns / m or more and 100 turns / m or less, When a curved or bent shape is formed on the modeling surface, the control unit sets the modeling path on the modeling surface to a path in which the modeling material is discharged while curving or bending the fiber bundle to the right side toward the front of the modeling direction when the fiber bundle is Z-twisted, and sets the modeling path to a path in which the modeling material is discharged while curving or bending the fiber bundle to the left side toward the front of the modeling direction when the fiber bundle is S-twisted, thereby forming the curved or bent shape. Additive manufacturing equipment.

6. A program for executing an additive manufacturing procedure in which a modeling material obtained by heating and melting a linear continuous fiber reinforced filament is ejected from a nozzle along a modeling path on a modeling surface to model a curved or bent shape on the modeling surface, The continuous fiber reinforced filament includes a substrate including a thermoplastic resin and at least one fiber bundle including continuous fibers impregnated in the substrate and extending in an axial direction; The continuous fibers of the fiber bundle are twisted about an axial core of the continuous fiber reinforced filament at 20 turns / m or more and 100 turns / m or less, On the computer, When the fiber bundle is Z-twisted, the modeling path on the modeling surface is a path for discharging the modeling material while curving or bending it to the right side toward the front of the modeling direction, and when the fiber bundle is S-twisted, the modeling path is a path for discharging the modeling material while curving or bending it to the left side toward the front of the modeling direction, thereby executing a procedure for modeling the curved shape or the bent shape. program.

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