Mold and preparation method and device of continuous fiber reinforced resin-based 3D printing wire

Abstract

The mold comprises an upper mold body and a lower mold body, a plurality of protrusions are arranged on the surface, facing the lower mold body, of the upper mold body, a plurality of pits are formed in the surface, facing the upper mold body, of the lower mold body, and the protrusions and the pits are oppositely arranged, so that a bent runner is formed when the upper mold body and the lower mold body are closed. The invention further provides a preparation method and device of the continuous fiber reinforced resin-based 3D printing wire. The mold is provided with a bent runner, continuous fibers can be fully impregnated in molten resin, then the continuous fibers are further shaped through the forming device and the cooling device, and the low-porosity and high-fiber-volume-fraction continuous fiber reinforced resin-based 3D printing wire is prepared through a one-step method. And the problems of high porosity, low fiber volume fraction content and repeated forming of the 3D printing wire material are relieved. The prepared continuous fiber reinforced resin-based 3D printing wire can be used for 3D printing forming of complex structural parts, and meanwhile the indexes such as light weight and high mechanical performance are met.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printing, and in particular to a method and a device for preparing a mold and a continuous fiber reinforced resin-based 3D printing filament. Background Art

[0002] Continuous fiber reinforced resin matrix composites are composite materials made of continuous fibers as reinforcement and resin polymer as matrix. Compared with other metal materials, continuous fiber reinforced resin matrix composites have the advantages of high strength, high stiffness, low density, and strong designability. Compared with traditional metal materials, composite materials have greater specific strength and specific stiffness, and they have the characteristics of fatigue resistance and corrosion resistance, making them an important substrate for main load-bearing structures and high-precision secondary load-bearing structures in the fields of aerospace, automobiles and ships, and have great application prospects.

[0003] The traditional molding processes of continuous fiber reinforced resin-based composite materials mainly include autoclave molding, compression molding, liquid molding, pultrusion molding, fiber winding molding, etc. On the one hand, this type of molding process has a complex process flow, often requires molds, has high costs, and has a long production cycle; on the other hand, the existence of molds limits the structure of the formed parts, making it difficult to manufacture complex-shaped components, and the production of complex-shaped components usually requires complex post-processing technology, which leads to a decrease in overall performance and an increase in processing costs. Compared with traditional composite material molding processes, 3D printing molding processes have the advantages of simple process, high material utilization, and low manufacturing costs. At the same time, it can realize the integrated molding of complex structures of continuous fiber reinforced composite materials without the need for molds, which can significantly reduce the manufacturing time and cost of advanced composite materials.

[0004] Although continuous fiber reinforced composites prepared by the fused deposition modeling (FDM) process meet the requirements of high design and rapid manufacturing, the high viscosity of thermoplastic resin makes it difficult to fully impregnate the fibers. Therefore, the prepared 3D printing filaments have high porosity and low fiber volume fraction, which affects the internal quality of 3D printed parts.

[0005] Therefore, how to effectively increase the fiber volume fraction and reduce the porosity of 3D printing filaments is a technical problem that needs to be urgently solved in this field. Summary of the invention

[0006] In view of this, the present application provides a mold, a method and an apparatus for preparing a continuous fiber reinforced resin-based 3D printing filament. The method provided in the present application can fully and evenly impregnate the continuous fiber in the resin, and the prepared continuous fiber reinforced resin-based 3D printing filament has a low porosity and a high fiber volume fraction.

[0007] The present application provides a mold, including an upper mold and a lower mold, wherein the surface of the upper mold facing the lower mold is provided with a plurality of protrusions, and the surface of the lower mold facing the upper mold is provided with a plurality of depressions, and the plurality of protrusions and the plurality of depressions are arranged opposite to each other, so that a curved flow channel is formed when the upper mold and the lower mold are closed.

[0008] In some specific implementations, the mold clearance of the curved flow channel is 1 mm to 10 mm;

[0009] The number of the protrusions and depressions is 3 to 8 pairs.

[0010] In some specific implementations, the protrusion is a cone-like structure, and the generatrix length of the protrusion is 5 mm to 30 mm;

[0011] The generatrix angle of the protrusion is 90° to 150°.

[0012] The present application also provides a device for preparing continuous fiber reinforced resin-based 3D printing filaments, comprising the mold described in the above technical solution;

[0013] a first resin feeding device in communication with a flow channel of the mold;

[0014] a fiber feeding device connected to the flow channel inlet of the mold;

[0015] A heating device for heating the mold;

[0016] A molding device is connected to the flow channel outlet of the mold.

[0017] In some specific implementations, it further includes a second resin feeding device in communication with the flow channel of the mold;

[0018] The first resin feeding device is connected to the flow channel inlet of the mold, and the second resin feeding device is connected to the middle section of the flow channel of the mold.

[0019] In some specific implementations, the first resin feeding device and the second resin feeding device are independently selected from twin-screw extruders.

[0020] In some specific implementations, the first resin feeding device is connected to the flow channel of the mold through the lower mold, and the second resin feeding device is connected to the flow channel of the mold through the upper mold.

[0021] In some specific implementations, the forming device includes a circular outlet mold or a square outlet mold.

[0022] The present application also provides a method for preparing a continuous fiber reinforced resin-based 3D printing filament, comprising:

[0023] The fibers and molten resin are respectively fed into the mold or device described in the above technical solution for impregnation, and the fibers impregnated with the resin are cooled and formed to obtain continuous fiber-reinforced resin-based 3D printing filaments.

[0024] In some specific implementations, the molten resin includes one or more of polyethylene, polypropylene, polycarbonate, polyphenylene sulfide, polyetheretherketone, polyetherketone, polyetherketoneketone, polyetheretherketone or polyaryletherketone, the melt index of the molten resin is above 90g / 10min, the fiber is carbon fiber, the linear density of the carbon fiber is 60tex to 1600tex, the mass percentage of the molten resin is 35% to 65%, and the mass percentage of the carbon fiber is 35% to 65%.

[0025] In some specific implementations, the impregnation temperature is 350° C. to 390° C., and the diameter of the continuous fiber reinforced resin-based 3D printing filament is 1 mm to 3 mm.

[0026] The mold provided in the present application includes an upper mold and a lower mold, wherein the surface of the upper mold facing the lower mold is provided with a plurality of protrusions, and the surface of the lower mold facing the upper mold is provided with a plurality of depressions, wherein the plurality of protrusions and the plurality of depressions are arranged relative to each other, so that a curved flow channel is formed when the upper mold and the lower mold are closed. The mold provided by the present application has a curved flow channel, and when preparing continuous fiber reinforced resin-based 3D printing filaments, the continuous fibers can be fully impregnated in the molten resin, and then further shaped by a molding device and a cooling device, so as to prepare low porosity and high fiber volume fraction continuous fiber reinforced resin-based 3D printing filaments in one step, thereby alleviating the problems of high porosity, low fiber volume fraction content, and multiple molding of 3D printing filaments. The continuous fiber reinforced resin-based 3D printing filaments prepared in the present application can be used for 3D printing molding of complex structural parts, while also meeting indicators such as lightweight and high mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of the structure of the mold provided in Example 1 of the present application;

[0028] Figure 2 A diagram of the device provided for Example 3 of the present application;

[0029] Figure 3 This is a schematic diagram of a molten resin extrusion method provided in an embodiment of the present application, wherein: Figure 3 (a) is a schematic diagram of a single twin-screw extruder described in the present application with dual flow channels connected to a mold; Figure 3 (b) is a schematic diagram of the connection between the dual flow channels of the two twin-screw extruders described in the present application and the mold; Figure 3 (c) is a schematic diagram showing the dual flow channels of the two twin-screw extruders described in the present application being connected to a mold;

[0030] Figure 4 This is a diagram of the wire forming mold described in Example 4 of the present application. DETAILED DESCRIPTION

[0031] It should be understood that the expression "one or more of..." includes each of the items recited after the expression individually and in various different combinations of two or more of the recited items, unless otherwise understood from the context and usage. The expression "and / or" in combination with three or more recited items should be understood to have the same meaning, unless otherwise understood from the context.

[0032] The use of the terms "comprising", "having" or "containing", including their grammatical synonyms, should generally be understood as open and non-restrictive, for example not excluding other unrecited elements or steps, unless otherwise specifically stated or otherwise understood from the context.

[0033] It should be understood that the order of steps or the order in which certain actions are performed is not important as long as the present invention remains operable. In addition, two or more steps or actions may be performed simultaneously.

[0034] The use of any and all examples or exemplary language, such as "for example" or "including", herein is intended only to better illustrate the invention and does not limit the scope of the invention unless otherwise claimed. No language in this specification should be construed as indicating that any non-claimed element is essential to the practice of the invention.

[0035] In addition, the numerical ranges and parameters used to define the present invention are approximate values, and the relevant values ​​in the specific embodiments have been presented as accurately as possible. However, any numerical value inherently inevitably contains standard deviations due to individual test methods. Therefore, unless otherwise expressly stated, it should be understood that all ranges, quantities, values ​​and percentages used in this disclosure are modified by "about". Here, "about" generally means that the actual value is within plus or minus 10%, 5%, 1% or 0.5% of a specific value or range.

[0036] The present application provides a mold, including an upper mold and a lower mold, wherein the surface of the upper mold facing the lower mold is provided with a plurality of protrusions, and the surface of the lower mold facing the upper mold is provided with a plurality of depressions, and the plurality of protrusions and the plurality of depressions are arranged opposite to each other, so that a curved flow channel is formed when the upper mold and the lower mold are closed.

[0037] See also Figure 1 , Figure 1A schematic diagram of the structure of the mold provided in the embodiment of the present application. 11 is an upper mold, 12 is a lower mold, 13 is a protrusion arranged on the surface of 11, 14 is a depression arranged on the surface of 12, the number of protrusions 13 is the same as the number of depressions 14, and the protrusions 13 and the depressions 14 are arranged relative to each other, so that a curved flow channel is formed when the upper mold and the lower mold are closed, and when the continuous fiber passes through the curved flow channel, it can be fully infiltrated with resin, thereby reducing the porosity of the 3D printing filament and increasing the fiber volume fraction.

[0038] In some specific implementations, the protrusion 13 is a cone-like structure, and its generatrix length m is 5 mm to 30 mm, preferably 10 mm to 25 mm, and more preferably 15 mm to 20 mm. Those skilled in the art know that the generatrix length m of the protrusion refers to the distance from the vertex of the protrusion to any point on the circumference of the bottom surface, such as Figure 1 As shown. The larger the busbar length m, the larger the contact area between the fiber, resin and mold, the better the impregnation effect, but the traction tension increases and the fiber is easily damaged; the smaller the busbar length m, the smaller the contact area, and the poorer the impregnation effect. In some specific implementations, the busbar angle α of the protrusion is 90° to 150°, preferably 100° to 140°, and more preferably 120° to 130°. Those skilled in the art are aware that the busbar angle α of the protrusion refers to the angle between any two busbars, such as Figure 1 As shown in the figure, the smaller the busbar angle α is, the better the impregnation effect is, but the traction tension is increased and the fiber is easily damaged; the larger the angle is, the smaller the traction tension is, but the impregnation effect is poor.

[0039] In some specific implementations, the mold clearance d of the curved flow channel is 1 mm to 10 mm, preferably 2 mm to 8 mm, and more preferably 4 mm to 6 mm. If the mold clearance is too small, the wetting effect is good, but the fiber will be damaged, causing fuzzing, and the silk material cannot be produced continuously. If the mold clearance is too large, the fiber cannot be fully contacted with the curved wavy flow channel, thereby affecting its wetting effect. It is known to those skilled in the art that the mold clearance d refers to the cross-sectional diameter of the curved flow channel formed when the upper mold and the lower mold are molded together.

[0040] In some specific implementations, the shapes and sizes of the protrusions and depressions may be similar or different, preferably similar or even identical, to ensure continuous processing of continuous fibers. In some specific implementations, the number of the protrusions and depressions is 3 to 8 pairs, preferably 4 to 6 pairs. The more the number of curved channels, the better the impregnation effect, but the traction tension increases, and the fibers are easily damaged. The fewer the number of curved channels, the smaller the traction tension, but the poorer the impregnation effect.

[0041] In some specific implementations, the upper mold 11 and the lower mold 12 are respectively provided with molten resin inlets, so that molten resin can be introduced from the upper mold and the lower mold at the same time to ensure uniform fiber impregnation.

[0042] The mold provided in the present application has a curved flow channel, which can enable the continuous fiber to be fully impregnated in the molten resin when preparing continuous fiber reinforced resin-based 3D printing filaments.

[0043] The present application also provides a device for continuous fiber reinforced resin-based 3D printing filaments, comprising: the above-mentioned mold;

[0044] a first resin feeding device in communication with a flow channel of the mold;

[0045] a fiber feeding device connected to the flow channel inlet of the mold;

[0046] A heating device for heating the mold;

[0047] A molding device is connected to the flow channel outlet of the mold.

[0048] See also Figure 2 , Figure 2 A device for continuous fiber reinforced resin-based 3D printing filament provided in an embodiment of the present application, wherein 1 is a mold, 2 is a first resin feeding device, 3 is a continuous fiber feeding device, 4 is a second resin feeding device, and 5 is a molding device.

[0049] The device for continuous fiber reinforced resin-based 3D printing filaments includes a mold 1, and the mold 1 has the same structure as the mold described above, and the present application will not repeat it here.

[0050] The device for continuous fiber reinforced resin-based 3D printing filaments comprises a first resin feeding device 2 connected to a flow channel of a mold 1, which is used to feed molten resin into the flow channel to infiltrate the continuous fibers.

[0051] In order to increase the adequacy of impregnation, the device of the continuous fiber reinforced resin-based 3D printing filament includes a second resin feeding device 4 connected to the flow channel of the mold 1, which is used to feed molten resin into the flow channel to impregnate the continuous fiber. In some specific implementations, the first resin feeding device 2 is connected to the flow channel inlet of the mold 1, and the second resin feeding device 4 is connected to the middle section of the flow channel of the mold 1. In some specific implementations, the first resin feeding device 2 is connected to the flow channel inlet of the upper mold of the mold 1, and the second resin feeding device 4 is connected to the middle section of the flow channel of the lower mold of the mold 1. The first resin feeding device 2 and the second resin feeding device 4 are respectively fed with molten resin from different positions and directions, so that the fiber is more fully impregnated. In some specific implementations, the first resin feeding device and the second resin feeding device are independently selected from a twin-screw extruder, which can fully melt the resin.

[0052] See also Figure 3 , Figure 3 Schematic diagram of the molten resin extrusion method provided in the embodiment of the present application. In some specific implementations, the first resin feeding device and the second resin feeding device are double flow channels of a twin-screw extruder, such as Figure 3 As shown in (a), it is a schematic diagram of a single twin-screw extruder with two flow channels connected to a mold, 21a is a first flow channel connected to the twin-screw extruder, 22a is a second flow channel connected to the twin-screw extruder, the first flow channel 21a is connected to the lower mold flow channel inlet of the mold 1a, and the second flow channel 22a is connected to the upper mold flow channel inlet of the mold 1a. In some specific implementations, the first resin feeding device and the second resin feeding device are two twin-screw extruders, such as Figure 3 As shown in (b), 21b is the flow channel of the first twin-screw extruder, 41b is the flow channel of the second screw extruder, the flow channel 21b of the first twin-screw extruder 2b is connected to the lower mold flow channel inlet of the mold 1b, and the flow channel 41b of the second twin-screw extruder 4b is connected to the upper mold flow channel inlet. In some specific implementations, the first resin feeding device and the second resin feeding device are two twin-screw extruders, such as Figure 3 As shown in (c), 21c is the flow channel of the first twin-screw extruder, 41c is the flow channel of the second twin-screw extruder, the flow channel 21c of the first twin-screw extruder is connected to the lower mold flow channel entrance of the mold 1c, and the flow channel 41c of the second twin-screw extruder is connected to the middle section of the upper mold flow channel of the mold 1c. The first resin feeding device 2 and the second resin feeding device 4 respectively feed molten resin from different positions and directions to make the fiber more fully impregnated.

[0053] The device for continuous fiber reinforced resin-based 3D printing filaments includes a fiber feeding device 3 connected to the flow channel of the mold 1, which is used to feed the continuous fiber into the flow channel to fully infiltrate the molten resin. In some specific implementations, the fiber feeding device 3 is a traction device that directly pulls the continuous fiber into the flow channel of the mold 1.

[0054] In some specific implementations, the device for continuous fiber reinforced resin-based 3D printing filaments further includes a yarn spreading device 6 connected to the fiber feeding device, which is used to fully spread the fibers.

[0055] The device for the continuous fiber reinforced resin-based 3D printing filament includes a heating device (not shown in the figure) for heating the mold, which can be an external heating device, that is, independently arranged outside the mold to achieve heating of the mold, or a built-in heating device, that is, arranged inside the mold to achieve heating of the mold. There is no special limitation in this application.

[0056] The device for continuous fiber reinforced resin-based 3D printing filaments includes a molding device 5 connected to the flow channel outlet of the mold 1, and the molding device 5 is used to control the diameter of the filaments. In some specific implementations, the molding device includes but is not limited to a mold with a circular outlet (such as Figure 4 As shown), this application has no special requirements for the selection of the forming mold.

[0057] In some specific implementations, the device for continuous fiber reinforced resin-based 3D printing filaments further includes a cooling device 6 connected to the forming device 5 for further shaping the filaments.

[0058] The device for continuous fiber reinforced resin-based 3D printing filament provided by the user is used in the following manner:

[0059] After the fibers are unrolled, they enter the flow channel of the mold through a traction device. At the same time, after the resin is melted, it is fed into the flow channel of the mold through a first resin feeding device and a second resin feeding device. The fibers are fully impregnated with the molten resin while running in the flow channel. Since the flow channel is curved, the fiber impregnation time is prolonged, thereby reducing the porosity of the wire and increasing its fiber volume fraction.

[0060] The present application also provides a method for preparing a continuous fiber reinforced resin-based 3D printing filament, comprising:

[0061] The fibers and the molten resin are respectively fed into the above-mentioned mold for impregnation, and the fibers impregnated with the resin are cooled and formed to obtain continuous fiber-reinforced resin-based 3D printing filaments.

[0062] The present application uses fiber and molten resin as raw materials to prepare continuous fiber reinforced resin-based 3D printing filaments, wherein the molten resin includes but is not limited to one or more of polyethylene, polypropylene, polycarbonate, polyphenylene sulfide, polyetheretherketone, polyetherketone, polyetherketoneketone, polyetheretherketoneketone or polyetherketoneetherketoneketone. The present application has no special requirements for the selection of molten resin. In some specific implementations, the melt index of the molten resin is 90g / 10min to 250g / 10min, preferably 90g / 10min to 200g / 10min. The supply rate of the molten resin is 1g / min to 10g / min, preferably 3g / min to 8g / min, and more preferably 4g / min to 6g / min.

[0063] In some specific implementations, the fiber is a continuous fiber, preferably a continuous carbon fiber, and the linear density of the continuous carbon fiber is 60 tex to 1600 tex, preferably 100 tex to 1200 tex, and more preferably 300 tex to 800 tex. The continuous carbon fiber is preferably a high-strength carbon fiber of T300 and above. In some specific implementations, the carbon fiber is a flat yarn. The pulling speed of the fiber is 0.1 m / min to 2 m / min, preferably 0.5 m / min to 1.5 m / min, and more preferably 0.8 m / min to 1.2 m / min.

[0064] In some specific implementations, the mass percentage of the molten resin in the continuous fiber reinforced resin-based 3D printing filament is 35% to 65%, preferably 40% to 60%, and more preferably 45% to 55%, which is continuous carbon fiber.

[0065] The present application first pre-treats the continuous carbon fiber tow, for example, placing a plurality of carbon fiber yarn tubes on the creel of the unwinding device, and passing the tractor through a yarn spreading device, such as a plurality of yarn spreading rollers, so that the fiber tow is fully spread. In some specific implementations, the yarn spreading device includes but is not limited to an airflow yarn spreading device, a sonic yarn spreading device, an ultrasonic yarn spreading device, an electrostatic yarn spreading device or a mechanical yarn spreading device. In some specific implementations, the yarn spreading device includes a yarn spreading roller, and the number of the yarn spreading rollers is 1 to 10, preferably 2 to 8, and more preferably 5 to 8. In some specific implementations, the fiber can also be subjected to high temperature treatment before the yarn spreading to remove the sizing agent contained in the fiber.

[0066] The present application preferably uses a twin-screw extruder to melt the resin to obtain a molten resin. In some specific implementations, the temperature of the first section of the twin-screw extruder barrel is 120-200°C, the temperature of the second section is 250-280°C, the temperature of the third section is 320-360°C, and the temperature of the fourth section is 300-360°C.

[0067] After the fiber is pretreated and the resin is melted, it is sent to the mold described in the above technical solution for full infiltration. In some specific implementations, during infiltration, the temperature of the mold is preferably 350°C to 390°C, preferably 360°C to 385°C, and more preferably 365°C to 380°C. In some specific implementations, the fiber pulling speed is 1m / min, and the resin supply rate is 5g / min.

[0068] After the infiltration is completed, the continuous fiber reinforced resin-based 3D printing filament is obtained after molding and cooling by the molding device and the cooling device. The present application has no special restrictions on the molding device. After the molding is completed, the diameter of the obtained filament is 0.5mm to 3mm, preferably 1.5mm to 2.5mm. The present application has no special restrictions on the cooling parameters, for example, it can be natural cooling.

[0069] This application adopts the hot melt method for online impregnation, which can obtain continuous fiber reinforced resin-based 3D printing filaments with low porosity and high fiber volume fraction, thereby improving the internal quality of 3D printed composite materials; by changing the die mouth of the molding mold, continuous fiber reinforced resin-based 3D printing filaments with different diameters can be prepared; at the same time, there is no need to introduce other additives, and the temperature resistance grade of the continuous fiber reinforced resin-based 3D printing filament will not be affected by other additives.

[0070] The present invention is further described below in conjunction with the following examples. The protection scope of the present invention is not limited by the following examples.

[0071] Example 1

[0072] This embodiment provides a mold, see Figure 1 , 11 is an upper die, 12 is a lower die, 13 is a protrusion, and 14 is a depression; the surface of the upper die facing the lower die is provided with three conical protrusions, and the surface of the lower die facing the upper die is provided with three inverted conical depressions, the three protrusions and the three depressions are the same in number, shape, and size and are relatively arranged, so that a curved flow channel is formed when the upper die and the lower die are closed, the closing gap d of the curved flow channel is 3mm, the generatrix length m of the protrusion is 5mm, and the generatrix angle α of the protrusion is 90°.

[0073] Example 2

[0074] (1) T800 carbon fiber with a linear density of 450 etx is unrolled and fed into the mold provided in Example 1 through a fiber feeding device at a pulling speed of 1 m / min.

[0075] (2) PAEK resin with a melt index of 90 g / 10 min is melted through a first twin-screw extruder and a second twin-screw extruder, respectively, and then extruded into a flow channel of a mold. The parameters of the first twin-screw extruder and the second twin-screw extruder are as follows: the temperature of the first section is 200° C., the temperature of the second section of the extruder is set to 280° C., the temperature of the third section of the extruder is set to 320° C., and the temperature of the fourth section of the extruder is set to 320° C.; the first twin-screw extruder extrude the molten resin to the inlet of the mold flow channel from the lower mold direction; the second twin-screw extruder extrude the molten resin to the middle section of the mold flow channel from the upper mold direction, so that the molten resin enters the flow channel from two directions to be impregnated with the carbon fiber, and the supply rate of the molten resin is 5 g / min; in the filament obtained after impregnation, the mass percentage of carbon fiber is 49.6%, and the mass percentage of the PEAK resin is 50.4%.

[0076] (3) The resin-impregnated fiber bundle is passed through a circular molding die with a diameter of 1 mm and air-cooled to obtain a continuous fiber-reinforced resin-based 3D printing filament with a diameter of 1 mm.

[0077] The performance of the continuous fiber reinforced resin-based 3D printing filament prepared in Example 2 was tested. The results are shown in Table 1. Table 1 is the test results of the filament performance prepared in Example 2 of the present application.

[0078] Table 1

[0079]

[0080] Example 3

[0081] The difference from Example 2 is that the fiber bundle impregnated with resin is passed through a circular molding die with a diameter of 3 mm, and the rest are the same.

[0082] The performance of the continuous fiber reinforced resin-based 3D printing filament prepared in Example 3 was tested. The results are shown in Table 2. Table 2 is the test results of the filament performance prepared in Example 3 of the present application.

[0083] Table 2

[0084]

[0085] Example 4

[0086] The difference from Example 2 is that the melt index of the PEAK resin is 200 g / 10 min, and the others are the same.

[0087] The performance of the continuous fiber reinforced resin-based 3D printing filament prepared in Example 4 was tested. The results are shown in Table 3. Table 3 is the test results of the filament performance prepared in Example 4 of the present application.

[0088] Table 3

[0089]

[0090] Comparative Example 1

[0091] The difference from Example 4 is that the mold is replaced with a straight flow channel mold, the mold gap d is 3 mm after mold closing, and other conditions are the same. The prepared 3D printing filament has the phenomenon of resin coating on the outside of the fiber, which makes it unusable for 3D printing.

[0092] Comparative Example 2

[0093] The difference from Example 4 is that: all the PEAK resin is fed into the flow channel of the mold from the first plastic feeding device, and other conditions are the same. The prepared 3D printing filament has the phenomenon of insufficient carbon fiber impregnation and dry fiber filaments on the outer surface, which makes it unusable for 3D printing.

[0094] It can be seen from the above embodiments and comparative examples that the continuous fiber reinforced resin-based 3D printing filament prepared using the mold provided by the present application has a porosity of 3.42% to 4.76%, which is lower than that of existing 3D printing filaments, a fiber volume fraction of 38.6% to 43.7%, and a tensile strength of 2120 MPa to 2306 MPa, and has good comprehensive performance.

[0095] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A mold, characterized in that: It comprises an upper die and a lower die, wherein the surface of the upper die facing the lower die is provided with a plurality of protrusions, and the surface of the lower die facing the upper die is provided with a plurality of depressions, wherein the plurality of protrusions and the plurality of depressions are arranged opposite to each other, so that a curved flow channel is formed when the upper die and the lower die are closed.

2. The mold according to claim 1, characterized in that: The mold clearance of the curved flow channel is 1 mm to 10 mm; The number of the protrusions and depressions is 3 to 8 pairs.

3. The mold according to claim 1, characterized in that: The protrusion is a cone-like structure, and the generatrix length of the protrusion is 5 mm to 30 mm; The generatrix angle of the protrusion is 90° to 150°.

4. A device for preparing continuous fiber reinforced resin-based 3D printing filaments, characterized in that: A mold comprising any one of claims 1 to 3; a first resin feeding device in communication with a flow channel of the mold; a fiber feeding device connected to the flow channel inlet of the mold; A heating device for heating the mold; A molding device is connected to the flow channel outlet of the mold.

5. The device according to claim 4, characterized in that Also included is a second resin feeding device in communication with the flow channel of the mold; The first resin feeding device is connected to the flow channel inlet of the mold, and the second resin feeding device is connected to the flow channel inlet or the flow channel middle section of the mold.

6. The device according to claim 4, characterized in that The first resin feeding device and the second resin feeding device are independently selected from a twin-screw extruder; The first resin feeding device is connected to the flow channel of the mold through the lower mold, and the second resin feeding device is connected to the flow channel of the mold through the upper mold.

7. The device according to claim 4, characterized in that The forming device comprises a circular outlet mold or a square outlet mold.

8. A method for preparing a continuous fiber reinforced resin-based 3D printing filament, characterized in that: include: The fibers and the molten resin are respectively fed into the mold according to any one of claims 1 to 3 for impregnation, and the fibers impregnated with the resin are cooled and formed to obtain continuous fiber-reinforced resin-based 3D printing filaments.

9. The preparation method according to claim 8, characterized in that: The molten resin includes one or more of polyethylene, polypropylene, polycarbonate, polyphenylene sulfide, polyetheretherketone, polyetherketone, polyetherketoneketone, polyetheretherketoneketone or polyetherketoneetherketoneketone, the melt index of the molten resin is 90g / 10min to 250g / 10min, the fiber is carbon fiber, the linear density of the carbon fiber is 60tex to 1600tex, the mass percentage of the molten resin is 35% to 65%, and the mass percentage of the carbon fiber is 35% to 65%.

10. The preparation method according to claim 8, characterized in that: The impregnation temperature is 350° C. to 390° C., and the diameter of the continuous fiber reinforced resin-based 3D printing filament is 1 mm to 3 mm.

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