JP2022075505A - Strand - Google Patents

Abstract

To provide a resin strand with superior bendability, enabling smooth building by a three-dimensional printer.SOLUTION: A resin strand 1 is linearly formed and used as a build material for a three-dimensional printer. The strand has an outer peripheral face in which a spiral groove portion 9 is formed along an axial direction.SELECTED DRAWING: Figure 1A

Description

The present invention relates to strands.

As a device for molding an object having a three-dimensional shape, a 3D (three-dimensional) printer that employs a heat-melting laminating method in which resins that have been made into a thermoplastic state by heat are stacked one by one is known. This 3D printer can form a three-dimensional object without the need for a mold, a jig, or the like. In addition, it is possible to model a three-dimensional object that is difficult to mold by injection molding technology.

As shown in FIG. 12, as a 3D printer, a linear resin strand (filament) 203 wound around a spool 201 is continuously sent to a nozzle 207 through a tube 205, and the strand 203 is plasticized by the heat of a heater. As a state of formation, there is one that is discharged from the nozzle 207 and laminated on the base 209 (see, for example, Patent Document 1).

JP-A-2019-123241

By the way, in the above 3D printer, when the supply path of the strand 203 sent from the spool 201 to the nozzle 207 has a bending point K, a bending force is applied to the strand 203 at the bending point K, and the strand 203 is damaged or damaged. There is a risk.

Therefore, an object of the present invention is to provide a resin strand having excellent bendability, which enables smooth modeling by a 3D printer.

The present invention has the following configuration.
A linearly formed resin strand used as a raw material for modeling a 3D printer.
A spiral groove is formed on the outer peripheral surface along the axial direction.
Strand.

According to the present invention, it is possible to provide a resin strand having excellent bendability, which can be smoothly modeled by a 3D printer.

It is a perspective view of the strand which concerns on this embodiment. It is sectional drawing which is perpendicular to the longitudinal direction of the strand which concerns on this embodiment. It is an overall block diagram of the manufacturing apparatus which manufactures a strand which concerns on this embodiment. It is a front view of the die provided in the strand drawer part of the resin bath part which constitutes a manufacturing apparatus. It is a perspective view of the strand of another structure. It is a perspective view of the strand of another structure. It is a perspective view of the strand of another structure. It is a perspective view of the strand of another structure. It is a perspective view of the strand of another structure. It is a perspective view of the strand of another structure. It is a schematic sectional drawing which shows the part of the outer peripheral surface of a strand enlarged. It is a perspective view of the strand of another structure. It is a schematic block diagram of a 3D printer using a resin strand.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(Strand)
1A is a perspective view of the strand according to the present embodiment, and FIG. 1B is a cross-sectional view perpendicular to the longitudinal direction of the strand according to the present embodiment.

As shown in FIGS. 1A and 1B, the strand 1 according to the present embodiment is a linear resin material used as a modeling raw material for a 3D printer. The strand 1 has a base material 3 containing a thermoplastic resin as a main component, and a plurality of fiber bundles 5 impregnated in the base material 3 and extending continuously in the axial direction. The fiber bundle 5 is a bundle of a plurality of fibers 7 and is arranged in the center of the strand 1 in a state of being twisted to each other. In this example, there are three fiber bundles 5, and these three fiber bundles 5 are twisted together. Further, the outer peripheral surface of the base material 3 and the outer peripheral surface of the strand 1 are formed in a substantially circular shape in a vertical cross section in the longitudinal direction (axial direction) of the strand 1 except for the groove portion 9 described later.

The strand 1 has a plurality of (three in this example) groove portions 9 on the outer peripheral surface thereof. These groove portions 9 are formed in a spiral shape along the axial direction. It is preferable that the groove portions 9 are formed at equal intervals in the circumferential direction in the vertical cross section in the axial direction, and the direction of the spiral and the pitch P of the spiral are the same. The pitch P of the spiral of the groove portion 9 is preferably 0.001 mm to 500 mm. Particularly preferably, it is 0.005 mm to 100 mm. The width dimension Wa of the groove 9 is preferably 0.001 mm to 10 mm, and particularly preferably 0.005 mm to 5 mm. The depth dimension H of the groove portion 9 is preferably 0.001 mm to 10 mm, and particularly preferably 0.005 mm to 1 mm.

The diameter d of the strand 1 is about 0.1 mm to 10 mm, and the ratio (P / d) of the diameter d to the pitch P is preferably 0.0001 to 5000, more preferably 0.001 to 500, and particularly 0. 0.01 to 50 is preferable. The ratio (P / Wa) of the pitch P to the width dimension Wa of the groove 9 is preferably 0.0001 to 500,000, more preferably 0.01 to 50,000, and particularly preferably 0.1 to 5,000. Within the above range, the bendability of the strand 1 described later can be improved.

The 3D printer using the strand 1 adopts a so-called heat-melting lamination method in which a three-dimensional shaped object is formed by gradually stacking the strands 1 in which the thermoplastic resin component is melted by heat. .. In this heat-melting lamination method, modeling is performed while adhering the previously formed layer and the next layer one by one in a semi-solid (softened) state. This 3D printer is not particularly limited as long as it can form a modeled object by gradually stacking resins in a thermoplastic state by heat. For example, examples of the 3D printer include a support plate that can be freely moved in the vertical, horizontal, and front-back directions, and a supply unit that supplies the thermoplastic resin component of the strand 1 to the support plate while plasticizing it.

For the fiber bundle 5 constituting the strand 1, organic fibers such as polyethylene fiber, aramid fiber and zylon fiber, and inorganic fiber such as boron fiber, glass fiber, carbon fiber, metal fiber and rock fiber can be used. As the reinforcing fiber, a surface-treated fiber can be used in order to improve the adhesion strength between the resin and the fiber.

The thermoplastic resin that is the main component of the base material 3 includes polyolefin resins such as polypropylene and polyethylene, acrylonitrile, butadiene, and styrene resins, polystyrene resins, polyethylene terephthalates, polyester resins such as polybutylene terephthalate and polylactic acid, and polyamide resins. Resin, aromatic polyamide resin, polyetherimide, polyallylimide, polyallylate, polyether ether ketone, polyallyl ether ketone, polybenzimidazole, polyether sulfone, polysulfone, polyvinylidene fluoride resin, liquid crystal polymer, polycarbonate resin , Polyacetal, or polyphenylene sulfide or the like can be used.

These may be used alone, or may improve the heat resistance, thermal deformation temperature, heat aging, tensile properties, bending properties, creep properties, compression properties, fatigue properties, impact properties, and sliding properties of the thermoplastic resin portion. In order to make it possible, a thermoplastic resin in which a plurality of resins are blended may be used. Examples include PEEK / PTFE and PEEK / PBI. Further, a resin obtained by adding carbon fiber, short fiber such as glass fiber, talc or the like to the resin can be used.

Antioxidants such as phenol-based, thioether-based and phosphite-based, ultraviolet absorbers such as benzotriazole-based and triazine-based, and metal inactivating agents such as hydrazide-based and amide-based are added to the thermoplastic resin to form a model. Durability can be improved.

By adding a phthalic acid-based or polyesul-based plasticizer, the flexibility of the thermoplastic resin can be improved, and the modeling accuracy at the time of modeling and the flexibility of the modeled object can be improved.

Halogen-based, phosphoric acid ester-based, inorganic-based, and intomescent-based flame retardants can be added to the thermoplastic resin to improve the flame retardancy of the modeled object.

A core material such as a phosphoric acid ester metal salt system or sorbitol can be added to the thermoplastic resin to control thermal expansion during molding and improve molding accuracy.

Permanent antistatic agents such as nonionic diameter, anionic type, and cationic type can be added to the thermoplastic resin to improve the antistatic property of the modeled object.

By adding a lubricant such as a hydrocarbon type or a metal soap type to the thermoplastic resin to improve the slipperiness of the continuous fiber reinforced strand, it is possible to improve the delivery of the strand during molding.

By the way, in a 3D printer that forms a modeled object using linear resin strands, the strands are fed from the spool toward the nozzle when the modeled object is modeled. At this time, if there is a bent portion in the supply path of the strand, a bending force is applied to the strand at this bent portion, and the strand may be damaged or damaged.

In recent years, in order to improve the mechanical strength of a modeled object, a fiber reinforced plastic (FRP: Fiber) using a fused deposition modeling (FDM) 3D printer using continuous fiber reinforced strands reinforced with fibers has been used. Reinforced Plastics) modeling methods have been proposed, and their applications are expanding. However, when modeling a model using existing continuous fiber reinforced strands, the flexibility of the continuous fiber reinforced strands is low at places where the curvature is large (radius of curvature is small), and fiber peeling occurs in which the internal fibers are peeled off. There is. Then, there is a difference between the design path and the path at the time of actual modeling, which may result in a decrease in the modeling accuracy of the modeled object and a possibility that voids are generated in the modeled object and the quality is deteriorated. These deteriorations in molding accuracy and quality tend to occur significantly when using strands having a large diameter.

On the other hand, according to the strand 1 according to the present embodiment, since the spiral groove portion 9 is formed on the outer peripheral surface along the axial direction, the surface area on the outer peripheral surface is increased and the bendability is improved. Can be done. As a result, when the strand 1 is sent from the spool to the nozzle in the 3D printer, even if a bending force is applied at the bending portion because the supply path has a bending portion, the strand 1 is bent without being damaged or damaged. It can be sent along the supplied supply route. Therefore, modeling with a 3D printer can be performed smoothly. In addition, it can be easily wound around the spool without being damaged or damaged.

Moreover, since a plurality of spiral groove portions 9 are formed, the bendability can be further improved. Further, since the plurality of groove portions 9 are formed at equal intervals in the circumferential direction in the vertical cross section of the strand 1 in the axial direction, and the spirals of these groove portions 9 are in the same direction and at the same pitch, the spiral portions 9 are formed in the same direction and at the same pitch. The bendability can be improved in a well-balanced manner. Further, it is possible to avoid breakage / damage of the strand in the bent portion without considering the position of the groove portion 9 in the strand 1 and the bending direction of the bent portion of the supply path.

Further, the strength of the strand 1 can be significantly increased by the fiber bundle 5 in which the fibers 7 are bundled, but the inclusion of the fiber bundle 5 makes it difficult to bend. However, good bendability can be ensured by the spiral groove portion 9 formed on the outer peripheral surface. Further, by providing such a spiral groove portion 9, as a secondary effect, when modeling a modeled object by a fused deposition modeling 3D printer, the strand 1 can be modeled while being satisfactorily bent. It is possible to suppress the deterioration of the quality due to the deterioration of the modeling accuracy of the modeled object and the generation of voids in the modeled object, and to model the high-quality modeled object.

Moreover, since the plurality of fiber bundles 5 in which the fibers 7 are bundled are twisted together, the bendability of the fiber bundle 5 itself can be improved, and the deterioration of the bendability due to the inclusion of the fiber bundles can be suppressed.

(manufacturing device)
Next, an example of a manufacturing apparatus for manufacturing the strand 1 according to the present embodiment will be described.
FIG. 2 is an overall configuration diagram of a manufacturing apparatus 100 for manufacturing the strand 1 according to the present embodiment.
As shown in FIG. 2, the manufacturing apparatus 100 includes a fiber material supply unit 11, a resin bath unit 13, a cooling unit 15, and a twisting unit 17. In the manufacturing apparatus 100, the fiber bundle 5 unwound from the fiber material supply unit 11 is impregnated with the thermoplastic resin R serving as the base material 3 by the resin bath unit 13 to be drawn out as a strand 1. Then, the strand 1 drawn out from the resin bath portion 13 is cooled by the cooling portion 15 while being rotated around the axis center by the twisting portion 17, and is taken up by the twisting portion 17.

The fiber material supply unit 11 includes a plurality of (three in this example) spools 21 and a plurality of guide rollers 23. A fiber bundle 5 is wound around each spool 21, and the fiber bundle 5 is sent out from these spools 21. Each fiber bundle 5 sent out from the spool 21 is aligned with each other in a state of being spaced apart from each other by a guide roller 23 and guided to the resin bath portion 13.

The resin bath portion 13 includes a tubular resin bathtub 25 extending vertically, and the thermoplastic resin R in a molten state is stored in the resin bathtub 25. The resin bathtub 25 is provided with a kneading extruder (not shown) that melts the raw material of the charged thermoplastic resin R and extrudes it into the resin bathtub 25, and the thermoplastic resin R melted from the kneading extruder 25 is provided. Will be supplied. The resin bathtub 25 has a fiber bundle introduction port 27 at the upper portion thereof, and the fiber bundle 5 is sent from the fiber bundle introduction port 27. Further, the resin bathtub 25 has a strand drawing portion 29 on the side portion at the lower end thereof, and the strand 1 in which the fiber bundle 5 is impregnated in the base material 3 is pulled out laterally from the strand drawing portion 29.

The resin bathtub 25 of the resin bath portion 13 is provided with an impregnation roller 41 and an introduction roller 45, which are rotatably supported around the horizontal axis, respectively, inside the resin bathtub 25. A plurality of impregnation rollers 41 are provided along the vertical direction in the resin bathtub 25, and the introduction rollers 45 are provided at the lower ends in the resin bathtub 25.

The three fiber bundles 5 sent from the fiber bundle introduction port 27 of the resin bathtub 25 are alternately hung and contacted with the impregnation roller 41. As a result, each fiber bundle 5 runs in a meandering manner in the resin bathtub 25. The impregnation roller 41 does not necessarily have to be rotatable. Further, the fiber bundle 5 is hung on the introduction roller 45 at the lower end in the resin bathtub 25, and its traveling track is changed from the vertical direction to the horizontal direction and guided to the strand drawing portion 29.

A die 55 is provided in the strand drawing portion 29 from which the strand 1 in which the fiber bundle 5 is impregnated in the base material 3 is drawn out. The die 55 has a circular opening 57 that narrows in the drawing direction of the strand 1. As shown in FIG. 3, the inner diameter of the opening 57 on the drawing direction side is formed to have a size corresponding to the outer diameter of the strand 1 to be manufactured. Further, the die 55 has a plurality of (three in this example) groove forming protrusions 59 protruding inward on the inner peripheral surface of the opening 57. It is preferable that these groove-forming protrusions 59 are formed at equal intervals in the circumferential direction in the vertical cross section of the strand 1 in the drawing direction.

FIG. 3 shows an example in which the groove-forming protrusions 59 of the die 55 are formed at equal intervals in the circumferential direction in a cross section perpendicular to the drawing direction of the strand 1, but the groove-forming protrusions 59 are not necessarily at equal intervals. It does not have to be formed. When the groove-forming protrusions 59 are not formed at equal intervals, the pitches of the grooves 9 are not evenly spaced, but because the grooves 9 are formed, the flexibility of the strand 1 is compared with the case where the grooves 9 are not formed. Can be improved.

As will be described later, a die without a groove forming protrusion 59 may be used.

The cooling unit 15 has a cooling tank 31 that is long along the drawing direction of the strand 1 drawn from the strand drawing portion 29 of the resin bath portion 13. Cooling water W is stored in the cooling tank 31 as a cooling medium. The strand 1 is drawn into the cooling tank 31 from the resin bath portion 13 side. The strand 1 drawn into the cooling tank 31 is cured by cooling the thermoplastic resin R serving as the base material 3 with the cooling water W stored in the cooling tank 31. The strand 1 in which the thermoplastic resin R is cooled by the cooling water W and cured is drawn out from the twisted portion 17 side of the cooling tank 31.

The twisted portion 17 has a lead-in roller 35, a take-up bobbin 37, and a case 39. The pull-in rollers 35 are provided on the cooling unit 15 side of the case 39, and are arranged in pairs so as to face each other. These pull-in rollers 35 pull the strand 1 from the cooling unit 15 into the case 39. The take-up bobbin 37 is rotated about an axis orthogonal to the extending direction of the strand 1. As a result, the take-up bobbin 37 winds up the strand 1 drawn into the case 39 by the pull-in roller 35. The case 39 is rotated about an axis along the extending direction of the strand 1. As a result, the strand 1 drawn from the resin bath portion 13, passes through the cooling portion 15, and is wound around the winding bobbin 37 of the twisting portion 17 is rotated around the shaft core to impart twisting. Various mechanisms can be adopted as means for imparting twist to the strand 1. For example, the strand 1 is taken up by a pair of rollers rotating in different rotational directions and sent out to the downstream side to the strand 1. It may be a twisting means for imparting twist.

(Production method)
Next, an example of a manufacturing method for manufacturing the strand 1 by the manufacturing apparatus 100 will be described.
In the manufacturing apparatus 100, the strand 1 is manufactured by performing an impregnation step, a twisting step, a cooling step, and a winding step.

(1) Impregnation Step The impregnation step is a step of impregnating the fiber bundle 5 with the thermoplastic resin R by the resin bath portion 13 of the manufacturing apparatus 100. In this impregnation step, the fiber bundle 5 fed out from the fiber material supply section 11 and introduced from the fiber bundle introduction port 27 of the resin bath section 13 passes through the resin bath section 13 and is stored inside the resin bathtub 25. The molten thermoplastic resin R is impregnated into the fiber bundle 5.

Each fiber bundle 5 is alternately hung on a plurality of impregnated rollers 41, and by traveling while contacting the outer peripheral surfaces of these impregnated rollers 41, the plurality of fibers 7 constituting each fiber bundle 5 are opened. Will be done. As a result, the fiber bundle 5 is sufficiently impregnated with the thermoplastic resin R between the fibers 7.

(2) Twisting Step The twisting step is a step of twisting the fiber bundles 5 impregnated with the thermoplastic resin R. The fiber bundle 5 is wound around the introduction roller 45 in a state of being spaced apart from each other, the traveling track is converted in the horizontal direction, and the fiber bundle 5 is guided to the strand drawing portion 29. At this time, the strand 1 drawn out to the downstream side of the resin bath portion 13 is rotated around the shaft core by the twisted portion 17. As a result, the fiber bundles 5 are twisted together from the introduction roller 45 toward the strand drawing portion 29 from a state of being spaced apart from each other.

The twisted fiber bundles 5 are gathered at the central portion of the opening 57 of the die 55, so that the outer periphery of the twisted fiber bundles 5 is evenly covered by the thermoplastic resin R in the circumferential direction. Therefore, from the opening 57 of the die 55, the periphery of the twisted fiber bundle 5 is evenly covered with the base material 3 made of the thermoplastic resin R, and the strands are not exposed from the outer periphery of the fibers 7 constituting the fiber bundle 5. 1 is pulled out (see FIG. 3).

Further, when the die 55 is pulled out as the strand 1 from the opening 57, a groove 9 is formed on the outer peripheral surface of the strand 1 by the groove forming protrusion 59 of the opening 57 of the die 55. At this time, since the strand 1 is rotated around the axis center by the twisted portion 17, the groove portions 9 on the outer peripheral surface are each formed in a spiral shape. As will be described later, a die without the groove forming protrusion 59 may be used. In this case, the groove 9 is formed on the base material 3 by twisting the strand 1.

(3) Cooling Step The cooling step is a step of cooling the strand 1 by the cooling unit 15. In this cooling step, the strand 1 drawn from the strand drawing portion 29 of the resin bath portion 13 is drawn into the cooling tank 31 of the cooling portion 15 and then pulled out. As a result, the strand 1 is cured by cooling the thermoplastic resin R serving as the base material 3 by the cooling water W stored in the cooling tank 31.

(4) Winding Step The winding step is a step of winding the strand 1 to the twisted portion 17. In this winding step, the strand 1 cooled by the cooling portion 15 is drawn into the case 39 by the lead-in roller 35 of the twisting portion 17, and is wound up by the take-up bobbin 37 in the case 39.

As described above, in the manufacturing apparatus 100, the strand 1 having a spiral groove portion 9 formed on the outer peripheral surface and having excellent flexibility can be easily manufactured by the above steps.

The structure of the strand 1 is not limited to the above embodiment. For example, in the above embodiment, the strand 1 having three fiber bundles 5 is exemplified, but the number of fiber bundles 5 is not limited to three. Further, after manufacturing the strand 1 having a circular cross-sectional view, a spiral groove portion 9 may be formed on the outer peripheral surface of the strand 1 by cutting or the like.

Hereinafter, strands having other structures will be described.
4 to 8 are perspective views of strands having other structures, respectively.

The strand 1A shown in FIG. 4 has a fiber bundle 5 in which a plurality of fibers 7 are bundled. The fiber bundle 5 is provided in the center of the base material 3 and extends along the axial direction while rotating along the groove 9. The outer peripheral surface of the base material 3, and thus the outer peripheral surface of the strand 1A, is formed in a substantially circular shape in a cross section perpendicular to the axial direction, except for the groove portion 9, similar to the strand 1. That is, the fiber bundle 5 is provided in a region within a concentric circle with respect to the outer peripheral surface of the strand 1A.

In the strand 1B shown in FIG. 5, the width dimension of the groove portion 9 of the strand 1A shown in FIG. 4 in the circumferential direction is reduced to increase the number of the groove portions 9. By narrowing the arrangement pitch of the groove portion 9 in the circumferential direction, the flexibility of the strand 1B can be improved and the bending resistance can be made uniform regardless of the bending direction.

In the strand 1C shown in FIG. 6, the fiber bundle 5 of the strand 1B shown in FIG. 5 is a three (plural) fiber bundle 5. The plurality of fiber bundles 5 are respectively arranged at positions where the center of the strand 1B is the center of point symmetry. In this case as well, the flexibility of the strand 1C and the uniformity of the bending resistance are improved. In this case, the groove portion 9 can be reliably formed even when the groove portion is difficult to be formed by twisting as in the strand 1D of FIG. 7, which will be described later, because the base material 3 is relatively hard.

The strand 1D shown in FIG. 7 is a strand manufactured by using three (plural) fiber bundles 5. In the production of the strand 1D in this case, a die without the groove forming protrusion 59 is used. Then, in the strand 1D, the groove portion 9 is formed by twisting the strand 1D itself, and by extension, the three (plural) fiber bundles 5 themselves. Therefore, in the strand 1D, the groove portion 9 formed on the outer peripheral surface is not concave but V-shaped. These groove portions 9 are also formed in a spiral shape, and the inner side surface thereof is formed so as to be smoothly connected to the outer peripheral surface of the strand 1D. In this case, since the groove portion 9 is formed by twisting the fiber bundle 5 itself, it is not necessary to separately process the groove portion 9, and the manufacturing process can be simplified.

As another example in which the groove is formed by twisting the strand itself and thus the fiber bundle itself using a die without the groove forming protrusion 59, the strand 1E of FIG. 8 and the strand 1F of FIG. 9 are shown.

The strand 1E shown in FIG. 8 contains a single fiber bundle 5. In the strand 1E, the groove 9 is formed by twisting the strand 1E itself and, by extension, the single fiber bundle 5 itself contained therein. In this case, the fiber bundle 5 is provided in the center of the base material 3 and extends along the axial direction while rotating along the groove portion 9.

Further, the strand 1F shown in FIG. 9 contains a plurality of fiber bundles 5, and is the same as the strand 1E shown in FIG. 8 as being configured. However, the degree of twist is larger (the pitch of the spiral wire is narrower) in the strand 1F than in the strand 1E. Therefore, the depth of the groove 9 is deeper in the strand 1F than in the strand 1E. As a result, the cross section of the strand 1D shown in FIG. 7 has an irregular shape in which three circles are combined, whereas the cross section of the strand 1F is formed in a shape closer to a circle.

FIG. 10 is a schematic cross-sectional view showing a partially enlarged shape of a cross section perpendicular to the axial direction of the strands 1E and 1F shown in FIGS. 8 and 9. Note that FIG. 10 schematically shows the groove portion 9, and the depth dimension H of the groove portion 9, the width dimension Wa of the groove portion 9, and the circumferential distance L between the groove portions 9 are examples.
The outer peripheral surface of the strand (outer peripheral surface 3a of the base material 3) shown in FIG. 10 has a substantially cross-sectional shape similar to that of the strand 1, except for the region between the circumferential end portions 9a and 9b of the same groove portion 9. It is formed in a circular shape. The substantially circular shape referred to here means a circular shape or a shape close to a circular shape, and specifically, a portion of the outer peripheral edge of the vertical cross section of the strand 1 excluding the region of the groove portion 9. Refers to a shape formed by arcs of the same circle. Further, each arc does not necessarily have to be an arc of the same circle, and each arc may be arranged including a specific radial position from the center of the strand 1. Alternatively, the circle circumscribing each arc may be concentric with the center of the strand 1. The shape of the outer peripheral surface other than the groove portion 9 of the above-mentioned strand is the same for the strands 1, 1A, 1B, and 1C shown in FIGS. 1A, 1B, and 4 to 6.

The strand 1G shown in FIG. 11 has no fiber bundle 5 and is composed only of the base material 3 made of a thermoplastic resin. Also in this case, the outer peripheral surface of the base material 3 and the outer peripheral surface of the strand 1G are formed in a substantially circular shape as described above in a cross section perpendicular to the axial direction, except for the groove portion 9.

In each of the strands 1A, 1B, 1C, 1D, 1E, 1F, and 1G described above, the spiral groove portion 9 is formed on the outer peripheral surface along the axial direction, so that the surface area on the outer peripheral surface is increased. Flexibility can be improved. For any of the strands, the fiber volume content, which is the ratio of the fibers to the entire strand, is preferably 5% or more and 85% or less in order to secure sufficient strength of the modeled object.

As described above, the present invention is not limited to the above-described embodiment, and can be modified or applied by those skilled in the art based on the mutual combination of the configurations of the embodiments, the description of the specification, and the well-known technique. It is also a matter of the present invention to do so, and it is included in the scope of seeking protection.

As described above, the following matters are disclosed in the present specification.
(1) A linearly formed resin strand used as a raw material for modeling a 3D printer.
A strand in which a spiral groove is formed along the axial direction on the outer peripheral surface.
According to this strand, since the spiral groove portion is formed on the outer peripheral surface along the axial direction, the surface area on the outer peripheral surface can be increased and the bendability can be improved.
As a result, when the strand is sent from the spool to the nozzle in the 3D printer, it is bent without being damaged or damaged even if a bending force is applied at the bending point because the supply path has a bending point. It can be sent along the supply route. Therefore, modeling with a 3D printer can be performed smoothly. In addition, it can be easily wound around the spool without being damaged or damaged.

(2) The strand according to (1), wherein the plurality of grooves formed in a spiral shape in the same direction and at the same pitch are formed at equal intervals in the circumferential direction in a vertical cross section in the axial direction.
According to this strand, since a plurality of spiral grooves are formed, the bendability can be further improved. Further, since a plurality of grooves are formed at equal intervals in the circumferential direction in a cross-sectional view and the spirals of these grooves are in the same direction and at the same pitch, the bendability is improved in a well-balanced manner in all directions. Can be done.

(3) The strand according to (1) or (2), which comprises a plurality of fibers or fiber bundles along the axial direction.
According to this strand, the strength can be significantly increased by the fiber or the fiber bundle. Further, although it becomes difficult to bend due to the inclusion of fibers or fiber bundles, good bendability can be ensured by the spiral groove formed on the outer peripheral surface. As a result, even when modeling a modeled object with a fused deposition modeling 3D printer, it is possible to model while bending the strands satisfactorily, resulting in a decrease in modeling accuracy of the modeled object and quality due to the generation of voids in the modeled object. It is possible to suppress deterioration and create high-quality models.

(4) The strand according to (3), wherein the fiber or the fiber bundle is twisted.
According to this strand, since the fiber or the fiber bundle is twisted, the bendability of the fiber or the fiber bundle itself can be enhanced, and the decrease in the bendability due to the inclusion of the fiber or the fiber bundle can be suppressed.

(5) Any one of (1) to (4), wherein the outer peripheral edge of the strand in the vertical cross section in the axial direction, excluding the region of the groove, is formed by an arc of the same circle. One of the strands listed.
According to this strand, the outer peripheral edge of the cross section is formed by an arc of the same circle, and the outer peripheral surface is formed into a substantially circular shape as a whole. Therefore, for example, when modeling a modeled object with a 3D printer, the supply amount of the strand is increased. It can be made constant and the quality of the modeled object can be stabilized.

1,1A, 1B, 1C Strand 5 Fiber bundle 7 Fiber 9 Groove

Claims (5)

A linearly formed resin strand used as a raw material for modeling a 3D printer.
A spiral groove is formed on the outer peripheral surface along the axial direction.
Strand. A plurality of the grooves formed in a spiral shape in the same direction and at the same pitch are formed at equal intervals in the circumferential direction in the vertical cross section in the axial direction.
The strand according to claim 1. Containing a plurality of fibers or fiber bundles along the axial direction,
The strand according to claim 1 or 2. The fibers or fiber bundles are twisted together,
The strand according to claim 3. Of the outer peripheral edge of the strand in the vertical cross section in the axial direction, the portion excluding the region of the groove is formed by an arc of the same circle.
The strand according to any one of claims 1 to 4.

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