A production system and method for 3D printing of continuous fiber impregnated reinforced resin

Abstract

The present invention belongs to the field of composite material manufacturing, and discloses a continuous fiber impregnated reinforced resin 3D printing integrated device and method. The production system for continuous fiber impregnated reinforced resin 3D printing successively includes a pre-tensioning device, an infrared radiation device, a swinging device, a pneumatic auxiliary spreading device, a wire material infiltration device, a screw extrusion device, and a 3D printing device. The feeding direction of the infiltration chamber and the feeding direction of the plastic melt conveying chamber are substantially parallel, that is, the screw extrusion device and the wire material infiltration device are also arranged substantially parallel. The screw extrusion device does not use a screw with a relatively small thread pitch in the vacuum exhaust section, but uses a screw with a relatively large thread pitch, and the thread pitch is 1.5D - 2D (D is the inner diameter of the barrel). By optimizing the device structure, the disadvantages of easy breakage of continuous fibers and easy carbonization of resin are reduced, the yield of products is improved, and stable production is achieved.

Description

Technical Field

[0001] The present invention belongs to the field of composite material manufacturing, and particularly relates to a production system and method for 3D printing of continuous fiber impregnated reinforced resin. Background Art

[0002] Using continuous fiber reinforced thermoplastic resin for 3D printing is a current research hotspot, mainly aiming to greatly improve the strength of 3D printing materials. The main method adopted is to directly introduce a continuous fiber bundle into the nozzle of the printer, and the continuous fiber bundle and the 3D printing filament pass through the nozzle of the printer simultaneously for printing. The main defect of this technology is that the interfacial bonding between the continuous fiber and the thermoplastic resin matrix is relatively poor, and the fiber bundle is not fully impregnated. This is mainly because the flow channel in the nozzle of the 3D printer is small and short, the residence time of the material in the nozzle is short, and there is also a lack of sufficient forming pressure, resulting in a poor impregnation effect of the resin matrix on the fiber bundle. This will not fully exert the reinforcing effect of the continuous fiber on the composite product. There are patents and commercial technologies that use a pre-impregnation tank to pre-impregnate continuous fibers to improve interfacial bonding, but this method has low production efficiency. The existing patent publication text CN 111186138 A discloses a 3D printing device for continuous fiber melt impregnation, which can better solve the balance problem between the interfacial bonding force of continuous fiber and thermoplastic resin matrix and production efficiency.

[0003] In order to further improve production efficiency, the inventor tried to combine a twin-screw extruder with the existing device. However, it was found in the test that when a conventional twin-screw extruder is combined with the existing 3D printing device for continuous fiber melt impregnation, fiber breakage is likely to occur. During long-term production, resin degradation and carbonization are also likely to occur in the impregnation die, affecting production stability and product quality. Summary of the Invention

[0004] In order to overcome the above-mentioned disadvantages and deficiencies of the prior art, the purpose of the present invention is to provide a production system and method for 3D printing of continuous fiber impregnated reinforced resin, realizing a one-step forming from resin modification to 3D printing. The resin has excellent performance, good fiber continuity, good interfacial bonding between the fiber and the resin matrix, and the fiber is fully dispersed. The printed composite product has excellent mechanical properties. At the same time, the integrated device can greatly improve production efficiency and reduce production costs.

[0005] The purpose of the present invention is achieved by the following solutions:

[0006] A production system for continuous fiber impregnated reinforced resin 3D printing, comprising: a pre-tensioning device having a plurality of tensioning rollers arranged in an interleaved manner for pre-dispersing a continuous fiber bundle; an infrared radiation device for pre-heating the pre-dispersed continuous fiber bundle; a swinging device located downstream of the infrared radiation device for disturbing the pre-heated continuous fiber bundle in a direction perpendicular to the fiber dragging direction and a direction parallel to the fiber dragging direction; a pneumatic auxiliary spreading device located downstream of the swinging device, the pneumatic auxiliary spreading device having a plurality of rotating rollers for conveying the continuous fiber bundle therein, and having an air flow inlet at the top, and the continuous fiber bundle is split and spread by high-pressure gas blowing; a wire material impregnation device, the wire material impregnation device comprising an impregnation chamber and a plastic melt conveying chamber arranged vertically, the impregnation chamber being used for mixing and impregnating the continuous fiber bundle from the pneumatic auxiliary spreading device with the plastic melt to obtain impregnated fibers; wherein, the feeding direction of the impregnation chamber and the feeding direction of the plastic melt conveying chamber are parallel; a screw extrusion device for melting and mixing resin raw materials to obtain a plastic melt and communicating with the plastic melt conveying chamber; a 3D printing device located downstream of the wire material impregnation device for heating and ejecting the impregnated fibers and 3D printing to obtain a 3D printed product of continuous fiber reinforced thermoplastic composite material.

[0007] Preferably, the screw extrusion device is a twin-screw extruder, which comprises a barrel, one end of the barrel has a feed inlet, the other end of the barrel has a discharge outlet, and the barrel includes a solid conveying section, a melting section, a melt conveying section and a vacuum exhaust section connected in sequence. The vacuum exhaust section is used for discharging the gas remaining in the material. The screw of the vacuum exhaust section no longer uses a screw with a smaller thread pitch, but uses a screw with a larger thread pitch. The thread pitch of the vacuum exhaust section is 1.5D - 2D, where D is the inner diameter of the barrel; the thread pitch of the solid conveying section is 1D - 2D, the thread pitch of the melting section is 0.5D - 1D, and the thread pitch of the melt conveying section is 1D; the screw diameter of the twin-screw extruder is 18mm - 90mm, the length-diameter ratio is 40 - 60, and the screw rotation speed is 0 - 500rpm / min.

[0008] Preferably, a cooling device is further arranged between the wire material impregnation device and the 3D printing device, and the cooling device is used for cooling and shaping the impregnated fibers.

[0009] Preferably, an unwinding roller device for winding the continuous fiber bundle is further arranged upstream of the pre-tensioning device.

[0010] Preferably, a fluid channel is provided in the plastic melt conveying chamber. The fluid channel forms a curved path inside the plastic melt conveying chamber by arranging a plurality of corners. Among them, the cross-section of the plastic melt conveying chamber along the length direction of the wire impregnation device is square, the side length of the square is L, the number of corners is three, namely R1, R2, and R3. The curvature radius of R1 is 0.1L - 0.3L, the curvature radius of R2 is 0.1L - 0.3L, and the curvature radius of R3 is 0.8L - 1.2L.

[0011] Preferably, a wavy flow channel is provided in the impregnation chamber. The wrapping angle of the wavy flow channel is 300° - 450°, the gap of the wavy flow channel is 8 - 10 mm. Heating rods are arranged at both the top and bottom of the wavy flow channel. A sizing die is arranged at the outlet end of the wavy flow channel. The diameter D of the sizing die is 0.7 - 1.2 mm, and the length is 15 - 20D. An internal haul-off roll is arranged inside the sizing die. The internal haul-off roll is a pair of metal rolls rotating towards each other, driven by a servo motor, used to haul the fiber bundle, and realize the impregnation of the molten resin on the fiber bundle through extrusion. The hauling speed of the internal haul-off roll for the fiber bundle is the same as the wire feeding speed of the 3D printing device.

[0012] Preferably, the swinging device includes a cam, a drive shaft, a coupling, and a stepping motor arranged in series. The cam is connected to the drive shaft by a key. The coupling and the drive shaft are driven by the stepping motor to drive the cam to rotate, so that the fiber bundle is disturbed along the direction perpendicular to the fiber dragging direction and the direction parallel to the fiber dragging direction. The cam swinging frequency of the swinging device is 10 - 20 r / min, and the eccentric amplitude is 10 - 15 mm. The multiple rotating rolls of the pneumatic auxiliary spreading device are driven by a motor, the air flow speed is 2 - 8 m / min, the air flow direction is perpendicular to the conveying direction of the fiber bundle and passes through between the single fibers of the fiber bundle. The fiber bundle is guided and limited by the multiple rotating rolls.

[0013] Preferably, the 3D printing device includes a divergent nozzle. The divergence angle of the divergent nozzle is 30 - 60°, the length of the divergent section is 1 - 1.5 times the diameter of the nozzle flow channel. The outlet of the divergent nozzle is chamfered. The edge width d of the divergent nozzle is 2 - 4 mm.

[0014] A 3D printing method for a production system of continuous fiber impregnated reinforced resin 3D printing includes the following steps:

[0015] (1) After the continuous fiber bundle is unrolled by the uncoiler device, it is first pre-dispersed by the pre-tensioning device, and then the upper and lower surfaces of the continuous fiber bundle are preheated by the infrared radiation device, and the preheating temperature is 100 - 200 °C;

[0016] (2) Pass the preheated continuous fiber bundle through a swinging device. The swinging device, through the eccentric rotation of a cam, perturbs the continuous fiber along directions perpendicular and parallel to the fiber dragging direction. The pneumatic auxiliary spreading device supplies air flow to the continuous fiber bundle, and the air flow direction is perpendicular to the conveying direction of the fiber bundle. Under the action of the initial fiber, the air flow velocity on both sides of the fiber is greater than the air flow blocked by the fiber in the middle, so that the pressure on both sides is lower. Under the action of the air pressure, the fiber bundle begins to gradually unfold to both sides, causing the fiber bundle to split. The final unfolded width of the fiber bundle is 15 - 25 mm, and the thickness is 0.03 - 0.06 mm;

[0017] (3) The screw extrusion device melts and plasticizes the resin raw material and supplies it to the wire impregnation device, and introduces the unfolded fiber bundle into the wire impregnation device. Under the action of the wavy flow channel, the resin matrix completes the impregnation process of the fiber bundle. The impregnated fiber is transported forward by the inner traction roller, formed through a circular shaping die, and then cooled and shaped by a cooling device. The shaped wire is a continuous fiber prepreg for 3D printing, with a diameter of 0.7 - 1.2 mm;

[0018] (4) After cooling the prepared continuous fiber prepreg, it is transported to the divergent nozzle of the 3D printing device through the wire feeding mechanism of the 3D printing device for 3D printing and forming, and finally a 3D printed product of continuous fiber impregnated and reinforced resin is obtained.

[0019] Preferably, the continuous fiber is glass fiber or carbon fiber; the resin used is at least one of polylactic acid, nylon, polyphenylene sulfide, or polyether ether ketone.

[0020] Preferably, in step (3), the amount of continuous fiber in the continuous fiber prepreg for 3D printing is 10 - 30% of the mass of the melt after melting and plasticizing in the screw extrusion device, preferably 20%.

[0021] Preferably, in step (3), at least one of an antioxidant and a lubricant can be added to the resin raw material in addition to the resin.

[0022] Preferably, in step (4), the printing temperature of the 3D printing is 200 - 400 °C, and the printing speed is 50 - 1000 mm / min.

[0023] Compared with the prior art, a production system for continuous fiber impregnated reinforced resin 3D printing of the present invention has the following beneficial effects: The plastic melt is modified by a screw extrusion device, and the continuous fiber impregnation reinforcement and 3D printing are effectively combined to achieve integrated production. The transfer link between resin modification, continuous fiber impregnation, and 3D printing is avoided, improving the production efficiency of the product. At the same time, by optimizing the device structure, the disadvantages of easy breakage of continuous fibers and easy carbonization of resin are reduced, improving the yield rate of the product and achieving stable production. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic diagram of a production system for continuous fiber impregnated reinforced resin 3D printing of the present invention.

[0025] Figure 2 is a three-dimensional structure diagram of the screw extrusion device and the wire impregnation device of the present invention.

[0026] Figure 3 is a partial cross-sectional view of the screw extrusion device and the wire impregnation device of the present invention.

[0027] Figure 4 is a structure diagram of the swing device of the present invention.

[0028] Figure 5 is a top view of the pneumatic auxiliary spreading device of the present invention.

[0029] Among them, 1-unwinding roller device, 2-pre-tensioning device, 201-tensioning roller, 3-infrared radiation device, 4-swing device, 401-cam, 402-drive shaft, 403-coupling, 404-step motor, 5-pneumatic auxiliary spreading device, 501-rotating roller, 6-wire impregnation device, 6a-impregnation chamber, 6b-plastic melt conveying chamber, 601-wavy flow channel, 602-heating rod, 603-sizing die, 604-inner traction roller, 7-screw extrusion device, 8-cooling device, 9-3D printing device, 901-divergent nozzle, 902-traction roller. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] The present invention will be further described in detail below in conjunction with the embodiments and the drawings, but the embodiments of the present invention are not limited thereto. PA6 used in the embodiments is BASF Ultramid B3S, PA6 / 66 (80 / 20) is BASF Ultramid B33SLX 09, PA12 is EMS's Grilamid L25, PA106 is Chendong HPANX6HF, and carbon fiber is Zhongfu Shenying SYT45.

[0031] In the examples, the tensile strength and flexural strength refer to the ISO527 standard, and the interlaminar shear samples refer to the JC / T773-2010 standard. Five samples are tested for each group, and the average value is taken.

[0032] For those not specified with specific conditions in the examples, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. For the reagents or instruments without indicating the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0033] As Figure 1 shown, a production system for continuous fiber impregnated reinforced resin 3D printing sequentially includes a unwind roller device 1, a pre-tensioning device 2, an infrared radiation device 3, a swing device 4, a pneumatic auxiliary spreading device 5, a wire impregnation device 6, a screw extrusion device 7, a cooling device 8 and a 3D printing device 9, and the overall layout is in a strip shape.

[0034] As Figure 1 shown, the pre-tensioning device 2 has a plurality of tensioning rollers 201 arranged staggeredly for pre-dispersing the continuous fiber bundle. In this embodiment, the number of tensioning rollers 201 is three, and the three tensioning rollers 201 are arranged staggeredly, making the conveying path of the continuous fiber bundle wavy.

[0035] As Figure 1 shown, the infrared radiation device 3 is used to preheat the pre-dispersed continuous fiber bundle. Among them, the infrared radiation device 3 includes a first infrared radiation module and a second infrared radiation module arranged up and down, and an infrared radiation channel for conveying the continuous fiber bundle is formed between them.

[0036] As Figure 1 、 Figure 4 and Figure 5As shown, there is a swinging device 4, which is located downstream of the infrared radiation device 3 and is used to disturb the preheated continuous fiber bundle along the directions perpendicular and parallel to the fiber dragging direction. There is a pneumatic auxiliary spreading device 5, which is located downstream of the swinging device 4. The pneumatic auxiliary spreading device 5 has multiple rotating rollers 501 for conveying the continuous fiber bundle, and has an air flow inlet at its top. The continuous fiber bundle is split and spread by the injection of high-pressure gas. The swinging device 4 includes a cam 401, a drive shaft 402, a coupling 403 and a stepping motor 404 arranged in series. The cam 401 is key-connected to the drive shaft 402. The coupling 403 and the drive shaft 402 are driven by the stepping motor 404 to drive the cam 401 to rotate, so that the fiber bundle is disturbed along the directions perpendicular and parallel to the fiber dragging direction, improving the impregnation effect of the resin matrix on the fiber bundle. While tensioning the fiber bundle, it can also ensure that the preheated fiber bundle becomes loose, facilitating subsequent yarn spreading. The swinging frequency of the cam 401 of the swinging device 4 is 10-20 r / min, and the eccentric amplitude is 10-15 mm; the multiple rotating rollers 501 of the pneumatic auxiliary spreading device 5 are driven by a motor, the air flow speed is 2-8 m / min, and the air flow direction is perpendicular to the conveying direction of the fiber bundle and passes through between the single fibers, which can effectively avoid fiber damage. The fiber bundle is guided and limited by the multiple rotating rollers 501. Among them, the number of the rotating rollers 501 is three, including two guiding rollers and one limiting roller. The position of the limiting roller can be adjusted up and down. The width of the single bundle of fibers after being spread by the pneumatic auxiliary spreading device 5 is 15-25 mm, and the thickness is 0.03-0.06 mm.

[0037] As Figures 1-3As shown in the figure, X is the length direction of the wire impregnation device 6, and Y is the width direction of the wire impregnation device 6. The wire impregnation device 6 includes an impregnation chamber 6a and a plastic melt delivery chamber 6b arranged vertically. The impregnation chamber 6a is used to mix and impregnate the continuous fiber bundle from the pneumatic spreading device 5 with the plastic melt delivered by the plastic melt delivery chamber 6b to obtain impregnated fibers. Among them, the feeding direction of the impregnation chamber 6a and the feeding direction of the plastic melt delivery chamber 6b are substantially parallel. A fluid channel is provided in the plastic melt delivery chamber 6b, and the fluid channel forms a curved path inside the plastic melt delivery chamber 6b by setting multiple corners. Among them, the cross-section of the plastic melt delivery chamber 6b along the length direction X of the wire impregnation device 6 is square, the side length of the square is L, the number of corners is three, namely R1, R2, and R3. The curvature radius of R1 is 0.1L - 0.3L, the curvature radius of R2 is 0.1L - 0.3L, and the curvature radius of R3 is 0.8L - 1.2L. A wavy flow channel 601 is provided in the impregnation chamber 6a. The wrapping angle of the wavy flow channel 601 is 300° - 450°, the gap of the wavy flow channel 601 is 8 - 10 mm. Heating rods 602 are arranged at both the top and bottom of the wavy flow channel 601. A sizing die 603 is provided at the outlet end of the wavy flow channel 601. The diameter D of the sizing die 603 is 0.7 - 1.2 mm, and the length is 15 - 20D. An internal traction roller 604 is arranged in the sizing die 603. The internal traction roller 604 is a pair of metal rollers rotating towards each other, driven by a servo motor, used to traction the fiber bundle, and realizes the impregnation of the fiber bundle by the molten resin through the extrusion effect. The traction speed of the internal traction roller 604 for the fiber bundle is the same as the wire feeding speed of the 3D printing device 9.

[0038] As Figure 1 and Figure 3As shown, a screw extrusion device 7 is used to melt resin raw materials to obtain a plastic melt, and is connected to the fluid passage of the plastic melt delivery chamber 6b. The screw extrusion device 7 is connected to the wire impregnation device 6 in a parallel manner. The screw extrusion device 7 is a twin-screw extruder, which includes a barrel. One end of the barrel has a feed inlet, and the other end has a discharge outlet. The barrel includes a solid conveying section, a melting section, a melt conveying section, and a vacuum exhaust section connected in sequence. The vacuum exhaust section is used to discharge the gas remaining in the material. The screw in the vacuum exhaust section no longer uses a conveying element with a smaller thread pitch, but uses a screw with a larger thread pitch. The thread pitch of the vacuum exhaust section is 1.5D - 2D, the thread pitch of the solid conveying section is 1D - 2D, the thread pitch of the melting section is 0.5D - 1D, and the thread pitch of the melt conveying section is 1D. D is the inner diameter of the barrel; the screw diameter of the screw extrusion device 7 is 18 mm - 90 mm, the length-diameter ratio is 40 - 60, the screw speed is 0 - 500 rpm / min. The resin raw material enters from the feed inlet, and through the flipping, mixing, and conveying of the twin-screw, the plastic melt is discharged from the discharge outlet and conveyed into the plastic melt delivery chamber 6b. Among them, the vacuum exhaust section is used to evacuate and extract the gas in the barrel to prevent the gas from entering the plastic melt delivery chamber 6b.

[0039] As Figure 1 shown, a 3D printing device 9 is located downstream of the wire impregnation device 6 and is used to heat and eject the impregnated fibers to obtain a 3D printed product of a continuous fiber reinforced thermoplastic composite material. The 3D printing device 9 includes a divergent nozzle. The divergence angle α of the divergent nozzle 901 is 30 - 60°, the length of the divergent section is 1 - 1.5 times the nozzle flow channel diameter. The outlet of the divergent nozzle 901 is rounded, and the edge width d of the divergent nozzle 901 is 2 - 4 mm. It can ensure a larger contact area between the nozzle edge and the product surface during printing, and the surface of the printed composite product is smooth and flat. Among them, the 3D printing device 9 also has a traction roller 902, and the traction roller 902 is used to guide the continuous fiber cooled by the cooling device 8 into the 3D printing device.

[0040] As Figure 1 shown, a cooling device 8 is also arranged between the wire impregnation device 6 and the 3D printing device 9. The cooling device 8 is used to cool and shape the impregnated fibers; an unwinding roller device 1 for winding a continuous fiber bundle is also arranged upstream of the pre-tensioning device 2.

[0041] In an embodiment not shown, the number of wire impregnation devices 6 can be configured as multiple according to needs. Multiple wire impregnation devices 6 are arranged side by side at a certain interval, and the continuous fiber bundles after spreading the yarn by the pneumatic auxiliary spreading device 5 are respectively conveyed into the multiple wire impregnation devices 6 to realize the simultaneous impregnation treatment of multiple wires and improve production efficiency.

[0042] A 3D printing method for a production system of continuous fiber impregnated reinforced resin 3D printing, comprising the following steps.

[0043] (1) After the continuous fiber bundle is unwound by the unwinding roller device 1, it first passes through the pre-tensioning device 2 for pre-dispersion, and then the upper and lower surfaces of the continuous fiber bundle are preheated by the infrared radiation device 3, and the preheating temperature is 100-200°C.

[0044] (2) The preheated continuous fiber bundle passes through the swinging device 4. Among them, the swinging device 4 makes the continuous fiber perturb along the direction perpendicular to the fiber dragging direction and the direction parallel to the fiber dragging direction through the eccentric rotation of the cam 401. The pneumatic auxiliary spreading device 5 provides an air flow to the continuous fiber bundle, and the air flow direction is perpendicular to the conveying direction of the fiber bundle. Under the action of the initial fiber, the air flow velocity on both sides of the fiber is greater than the air flow blocked by the fiber in the middle, so that the pressure on both sides is lower. Under the action of the air pressure, the fiber bundle begins to gradually unfold to both sides, so that the fiber bundle is split. The final unfolded width of the fiber bundle is 15-25 mm and the thickness is 0.03-0.06 mm.

[0045] (3) The screw extrusion device 7 melts and plasticizes the resin raw material and feeds it into the wire impregnation device 6, and introduces the unfolded fiber bundle into the wire impregnation device 6. Under the action of the wavy flow channel 601, the impregnation process of the resin matrix on the fiber bundle is completed. The impregnated fiber is conveyed forward by the inner traction roller 604, formed through the circular shaping die 603, and then cooled and shaped by the cooling device 8. The shaped wire is a continuous fiber prepreg that can be used for 3D printing, with a diameter of 0.7-1.2 mm.

[0046] (4) The prepared continuous fiber prepreg is cooled and then conveyed to the divergent nozzle of the 3D printer by the wire feeding mechanism of the 3D printing device 9 for 3D printing and shaping, and finally a 3D printed product of continuous fiber impregnated reinforced resin is obtained.

[0047] The continuous fiber described is glass fiber or carbon fiber; the resin used is at least one of polylactic acid, nylon, polyphenylene sulfide or polyether ether ketone.

[0048] In the continuous fiber prepreg that can be used for 3D printing in step (3), the dosage of the continuous fiber is 10-30% of the mass of the melt after melting and plasticizing in the screw extrusion device 7, preferably 20%.

[0049] In the resin raw material in step (3), at least one of an antioxidant and a lubricant can be added in addition to the resin.

[0050] The printing temperature of the 3D printing in step (4) is 200-400°C, and the printing speed is 50-1000 mm / min.

[0051] Example 1

[0052] Adopt a 3D printing method of a production system for continuous fiber impregnated reinforced resin 3D printing of the present invention, wherein the parameters are as follows: the wrapping angle of the wavy channel 601 in the wire impregnation device 6 is 350°, the channel gap is 10 mm, the traction speed of the inner traction roller 604 is 5 m / min, the diameter D of the sizing die 603 is 1 mm, and the length is taken as 15 times the diameter D. The swing frequency of the cam 401 in the swing device 4 is 12 r / min, and the eccentric amplitude is 10 mm. The air flow speed of the gas-assisted device is 5 m / min, the width of a single fiber bundle after spreading the yarn by the pneumatic spreading device 5 is 20 mm, the thickness is 0.05 mm, the preheating temperature of the infrared radiation device 3 is 180 °C, the diameter of the sizing die 603 is 1 mm, and the diameter of the obtained continuous fiber prepreg filament is 1 mm. The divergence angle α of the divergent nozzle of the 3D printing device 9 is 60°, the length of the divergent section is 1.2 times the diameter of the divergent nozzle channel, the edge width d of the divergent nozzle is 3 mm, the printing temperature is 280 °C, and the printing rate is 120 mm / min. The screw extrusion device 7 adopts a twin-screw extruder, the screw diameter is 18 mm, the length-diameter ratio is 48, the screw speed is 150 rpm / min, the processing temperature is 260 °C, the solid conveying section adopts 3 screw elements with a thread pitch of 1D and 3 screw elements with a thread pitch of 2D, the melting section adopts 1 screw element with a thread pitch of 0.5D and 4 screw elements with a thread pitch of 1D, the melt conveying section adopts 4 screw elements with a thread pitch of 1D, and the vacuum exhaust section adopts a screw section composed of 2 screw elements with a 2D thread pitch. The R1 = 0.1L, R2 = 0.1L, and R3 = 1L of the plastic melt conveying chamber 6b. The fiber bundle is carbon fiber, and the dosage of carbon fiber is 20% of the weight of the modified resin; the used modified resin is modified nylon 6, and has the following weight percentage formula:

[0053] PA6 79.4%;

[0054] PA6 / 66 (80 / 20) 20%;

[0055] Antioxidant 1098 0.3%;

[0056] Lubricant EBS 0.3%.

[0057] Comparative Example 1 is the same modified resin as that in Example 1 prepared using the device in the patent publication text CN 111186138 A, where the parameters are as follows: the wrapping angle of the wavy channel 601 in the wire impregnation device 6 is 350°, the channel gap is 10 mm, the traction speed of the inner traction roller 604 is 5 m / min, the diameter D of the shaping die 603 is 1 mm, and the length is taken as 15 times the diameter D. The swing frequency of the cam 401 in the swing device 4 is 12 r / min, and the eccentric amplitude is 10 mm. The air flow speed of the pneumatic auxiliary spreading device 5 is 5 m / min. The width of a single bundle of fibers after spreading by the pneumatic auxiliary spreading device 5 is 20 mm, and the thickness is 0.05 mm. The preheating temperature of the infrared radiation device 3 is 180 °C, the diameter of the shaping die 603 is 1 mm, and the diameter of the continuous fiber prepreg obtained is 1 mm. The divergence angle α of the divergent nozzle of the 3D printing device 9 is 60°, the length of the divergent section is 1.2 times the diameter of the divergent nozzle channel, the edge width d of the divergent nozzle is 3 mm, the printing temperature is 280 °C, and the printing rate is 120 mm / min. The screw extrusion device 7 uses a twin-screw, the screw diameter is 18 mm, the length-diameter ratio is 48, the screw speed is 150 rpm / min, the processing temperature is 260 °C. In the solid conveying section, 3 screw elements with a thread pitch of 1D and 3 screw elements with a thread pitch of 2D are used. In the melting section, 1 screw element with a thread pitch of 0.5D and 4 screw elements with a thread pitch of 1D are used. In the melt conveying section, 4 screw elements with a thread pitch of 1D are used. The vacuum exhaust section uses a screw section composed of 2 screw elements of 0.75D + 4 screw elements of 0.5D. The screw extrusion device 7 is connected to the wire impregnation device 6 at a right angle, that is, the feeding direction of the screw extrusion device 7 is perpendicular to the feeding direction of the wire impregnation device 6.

[0058] That is, the difference between Comparative Example 1 and Example 1 is only that: in Comparative Example 1, a conventional twin-screw combination is used, that is, the vacuum exhaust section uses a screw section composed of 2 screw elements of 0.75D + 4 screw elements of 0.5D, and the screw extrusion device 7 is connected to the wire impregnation device 6 at a right angle; while in Example 1, the twin-screw vacuum exhaust section uses a screw section composed of 2 screw elements of 2D, and the screw extrusion device 7 is connected to the wire impregnation device 6 in a parallel manner, and R1 = 0.1L, R2 = 0.1L, R3 = 1L in the plastic melt conveying chamber 6b.

[0059] Table 1 Performance comparison between Comparative Example 1 and Example 1.

[0060]

[0061] Example 2

[0062] A 3D printing method using a production system for continuous fiber impregnated reinforced resin 3D printing according to the present invention, wherein the parameters are as follows: the wrapping angle of the wavy channel 601 in the wire impregnation device 6 is 400°, the channel gap is 8 mm, the traction speed of the inner traction roller 604 is 4 m / min, the diameter D of the sizing die 603 is 0.8 mm, and the length is taken as 20 times the diameter D. The swing frequency of the cam 401 in the swing device 4 is 12 r / min, and the eccentric amplitude is 10 mm. The air flow speed of the gas-assisted device is 5 m / min, the width of a single fiber bundle after spreading the yarn by the pneumatic spreading device 5 is 20 mm, the thickness is 0.05 mm, the preheating temperature of the infrared radiation device 3 is 180 °C, the diameter of the sizing die 603 is 0.8 mm, and the diameter of the obtained continuous fiber prepreg is 0.8 mm. The divergence angle α of the divergent nozzle of the 3D printing device 9 is 60°, the length of the divergent section is 1.2 times the diameter of the divergent nozzle channel, the edge width d of the divergent nozzle is 3 mm, the printing temperature is 270 °C, and the printing rate is 150 mm / min. The screw extrusion device 7 uses a twin screw, the screw diameter is 18 mm, the length-diameter ratio is 48, the screw speed is 200 rpm / min, the processing temperature is 240 °C, the solid conveying section uses 3 screw elements with a thread pitch of 1D and 3 screw elements with a thread pitch of 2D, the melting section uses 1 screw element with a thread pitch of 0.5D and 4 screw elements with a thread pitch of 1D, the melt conveying section uses 4 screw elements with a thread pitch of 1D, and the twin screw vacuum exhaust section uses 3 conveying screw elements with a pitch of 1.5D. For the plastic melt conveying chamber 6b, R1 = 0.2L, R2 = 0.2L, and R3 = 0.9L. The fiber bundle is carbon fiber, and the modified resin used is modified nylon 12, and it has the following weight percentage formula:

[0063] PA12 84.4%;

[0064] PA6 15%;

[0065] Antioxidant 1098 0.3%;

[0066] Lubricant EBS 0.3%.

[0067] Comparative Example 2 is the same modified resin prepared by an existing 3D printing device for continuous fiber melt impregnation, with the following parameters: the wrapping angle of the wavy channel 601 in the wire impregnation device 6 is 400°, the channel gap is 8 mm, the traction speed of the inner traction roller 604 is 4 m / min, the diameter D of the sizing die 603 is 0.8 mm, and the length is taken as 20 times the diameter D. The swing frequency of the cam 401 in the swing device 4 is 12 r / min, and the eccentric amplitude is 10 mm. The air flow speed of the pneumatic auxiliary spreading device 5 is 5 m / min. The width of a single bundle of fibers after spreading by the pneumatic auxiliary spreading device 5 is 20 mm, and the thickness is 0.05 mm. The preheating temperature of the infrared radiation device 3 is 180 °C, the diameter of the sizing die 603 is 0.8 mm, and the diameter of the continuous fiber prepreg wire prepared is 0.8 mm. The divergence angle α of the divergent nozzle of the 3D printing device 9 is 60°, the length of the divergent section is 1.2 times the diameter of the divergent nozzle channel, the edge width d of the divergent nozzle is 3 mm, the printing temperature is 270 °C, and the printing rate is 150 mm / min. The screw extrusion device 7 uses a twin-screw, the screw diameter is 18 mm, the length-diameter ratio is 48, the screw rotation speed is 200 rpm / min, the processing temperature is 240 °C. The solid conveying section uses 3 screw elements with a thread pitch of 1D and 3 screw elements with a thread pitch of 2D. The melting section uses 1 screw element with a thread pitch of 0.5D and 4 screw elements with a thread pitch of 1D. The melt conveying section uses 4 screw elements with a thread pitch of 1D. The vacuum exhaust section uses a screw section composed of 2 screw elements of 0.75D + 4 screw elements of 0.5D. The screw extrusion device 7 is connected to the wire impregnation device 6 at a right angle, that is, the feeding direction of the screw extrusion device 7 is perpendicular to the feeding direction of the wire impregnation device 6.

[0068] That is, the only difference between Comparative Example 2 and Example 2 is that in Comparative Example 2, a conventional twin-screw combination is used, that is, the vacuum exhaust section uses a screw section composed of 2 screw elements of 0.75D + 4 screw elements of 0.5D, and the screw extrusion device 7 is connected to the wire impregnation device 6 at a right angle; while in Example 2, the vacuum exhaust section of the twin-screw uses a screw section composed of 3 screw elements of 1.5D, and the screw extrusion device 7 is connected to the wire impregnation device 6 in a parallel manner, and R1 = 0.2L, R2 = 0.2L, R3 = 0.9L in the plastic melt conveying chamber 6b.

[0069] Table 2 Performance comparison between Comparative Example 2 and Example 2.

[0070]

[0071] Example 3

[0072] A 3D printing method using a production system for continuous fiber impregnated reinforced resin 3D printing according to the present invention, with the following parameters: the wrapping angle of the wavy channel 601 in the wire impregnation device 6 is 320°, the channel gap is 8 mm, the traction speed of the inner traction roller 604 is 5 m / min, the diameter D of the sizing die 603 is 1.1 mm, and the length is taken as 15 times the diameter D. The swing frequency of the cam 401 in the swing device 4 is 10 r / min, and the eccentric amplitude is 12 mm. The air flow speed of the pneumatic auxiliary spreading device 5 is 4 m / min. After spreading the yarn by the pneumatic auxiliary spreading device 5, the width of a single fiber bundle is 20 mm, and the thickness is 0.05 mm. The preheating temperature of the infrared radiation device 3 is 150 °C, the diameter of the sizing die 603 is 1.1 mm, and the diameter of the obtained continuous fiber prepreg is 1.1 mm. The divergence angle α of the divergent nozzle of the 3D printing device 9 is 60°, the length of the divergent section is 1.2 times the diameter of the divergent nozzle channel, the edge width d of the divergent nozzle is 3 mm, the printing temperature is 285 °C, and the printing rate is 180 mm / min. The screw extrusion device 7 uses a twin screw, the screw diameter is 18 mm, the length-diameter ratio is 48, the screw speed is 200 rpm / min, the processing temperature is 260 °C. The solid conveying section uses 3 screw elements with a thread pitch of 1D and 3 screw elements with a thread pitch of 2D. The melting section uses 1 screw element with a thread pitch of 0.5D and 4 screw elements with a thread pitch of 1D. The melt conveying section uses 4 screw elements with a thread pitch of 1D. The twin screw vacuum exhaust section uses a screw section composed of 5 screw elements with a thread pitch of 1.5D. The plastic melt conveying chamber 6b has R1 = 0.2L, R2 = 0.2L, and R3 = 0.9L. The fiber bundle is carbon fiber, and the modified resin used is modified nylon 106, with the following weight percentage formula:

[0073] PA106 79.4%;

[0074] PA6 20%;

[0075] Antioxidant 1098 0.3%;

[0076] Lubricant EBS 0.3%;

[0077] Comparative Example 3 is the same modified resin prepared by an existing 3D printing device for continuous fiber melt impregnation, with the following parameters: the wrapping angle of the wavy channel 601 in the wire impregnation device 6 is 320°, the channel gap is 8 mm, the traction speed of the inner traction roller 604 is 5 m / min, the diameter D of the sizing die 603 is 1.1 mm, and the length is taken as 15 times the diameter D. The swing frequency of the cam 40118 in the swing device 4 is 10 r / min, and the eccentric amplitude is 12 mm. The air flow speed of the pneumatic auxiliary spreading device 5 is 4 m / min. The width of a single bundle of fibers after spreading by the pneumatic auxiliary spreading device 5 is 20 mm, and the thickness is 0.05 mm. The preheating temperature of the infrared radiation device 3 is 150 °C, the diameter of the sizing die 603 is 1.1 mm, and the diameter of the continuous fiber prepreg wire prepared is 1.1 mm. The divergence angle α of the divergent nozzle of the 3D printing device 9 is 60°, the length of the divergent section is 1.2 times the diameter of the divergent nozzle channel, the edge width d of the divergent nozzle is 3 mm, the printing temperature is 285 °C, and the printing rate is 180 mm / min. The screw extrusion device 7 uses a twin-screw, the screw diameter is 18 mm, the length-diameter ratio is 48, the screw rotation speed is 200 rpm / min, the processing temperature is 260 °C. The solid conveying section uses 3 screw elements with a thread pitch of 1D and 3 screw elements with a thread pitch of 2D. The melting section uses 1 screw element with a thread pitch of 0.5D and 4 screw elements with a thread pitch of 1D. The melt conveying section uses 4 screw elements with a thread pitch of 1D. The twin-screw vacuum exhaust section uses a screw section composed of 2 screw elements of 0.75D + 4 screw elements of 0.5D. The screw extrusion device 7 is connected to the wire impregnation device 6 at a right angle, that is, the feeding direction of the screw extrusion device 7 is perpendicular to the feeding direction of the wire impregnation device 6.

[0078] That is, the only difference between Comparative Example 3 and Example 3 is that in Comparative Example 3, a conventional twin-screw combination is used, that is, the vacuum exhaust section uses a screw section composed of 2 screw elements of 0.75D + 4 screw elements of 0.5D, and the screw extrusion device 7 is connected to the wire impregnation device 6 at a right angle; while in Example 3, the twin-screw vacuum exhaust section uses a screw section composed of 5 screw elements of 1.5D, and the screw extrusion device 7 is connected to the wire impregnation device 6 in a parallel manner, and in the plastic melt conveying chamber 6b, R1 = 0.2L, R2 = 0.2L, and R3 = 0.9L.

[0079] Table 3 Performance comparison between Comparative Example 3 and Example 3.

[0080]

[0081] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A production system for continuous fiber impregnated reinforced resin 3D printing, characterized in that, Comprising: A pre-tensioning device having a plurality of tensioning rollers arranged in an interleaved manner for pre-dispersing a continuous fiber bundle; An infrared radiation device for pre-heating the pre-dispersed continuous fiber bundle; A swinging device located downstream of the infrared radiation device for disturbing the pre-heated continuous fiber bundle in a direction perpendicular to the fiber dragging direction and a direction parallel to the fiber dragging direction; A pneumatic auxiliary spreading device located downstream of the swinging device. The pneumatic auxiliary spreading device has a plurality of rotating rollers for conveying the continuous fiber bundle, and an air flow inlet at its top, and the continuous fiber bundle is split and spread by high-pressure gas blowing; A wire material infiltration device comprising an infiltration chamber and a plastic melt conveying chamber arranged vertically. The infiltration chamber is used for mixing and infiltrating the continuous fiber bundle from the pneumatic auxiliary spreading device with the plastic melt to obtain infiltrated fibers; wherein, the feeding direction of the infiltration chamber and the feeding direction of the plastic melt conveying chamber are parallel; wherein, a fluid channel is provided in the plastic melt conveying chamber, and the fluid channel forms a curved path by setting three corners, and the radii of curvature of the three corners are respectively R1 = 0.1L - 0.3L, R2 = 0.1L - 0.3L, R3 = 0.8L - 1.2L, and L is the side length of the cross-section of the plastic melt conveying chamber; A screw extrusion device for melting a resin raw material to obtain a plastic melt and communicating with the plastic melt conveying chamber; the screw extrusion device is a twin-screw extruder, which includes a barrel. The barrel includes a solid conveying section, a melting section, a melt conveying section, and a vacuum exhaust section connected in sequence. The thread pitch of the screw in the vacuum exhaust section is 1.5D - 2D, the thread pitch of the solid conveying section is 1D - 2D, the thread pitch of the melting section is 0.5D - 1D, the thread pitch of the melt conveying section is 1D, and D is the inner diameter of the barrel. The screw extrusion device is connected in parallel with the plastic melt conveying chamber; A 3D printing device located downstream of the wire material infiltration device for heating and ejecting the infiltrated fibers and performing 3D printing to obtain a 3D printed product of a continuous fiber reinforced thermoplastic composite material.

2. The production system for continuous fiber impregnated reinforced resin 3D printing according to claim 1, wherein: One end of the barrel has a feed port, and the other end of the barrel has a discharge port; the screw diameter of the screw extrusion device is 18 mm - 90 mm, the length-diameter ratio is 40 - 60, and the screw rotation speed is 0 - 500 rpm / min.

3. A production system for continuous fiber impregnated reinforced resin 3D printing according to claim 1, characterized in that: A cooling device is further arranged between the wire material infiltration device and the 3D printing device for cooling and shaping the infiltrated fibers; a unwind roller device for winding the continuous fiber bundle is further arranged upstream of the pre-tensioning device.

4. The production system for continuous fiber impregnated reinforced resin 3D printing according to claim 1, wherein: The cross-section of the plastic melt conveying chamber along the length direction of the wire material infiltration device is square.

5. A production system for continuous fiber impregnated reinforced resin 3D printing according to claim 1, characterized in that: The infiltration chamber is provided with a wavy flow channel. The wrapping angle of the wavy flow channel is 300° - 450°. The gap of the wavy flow channel is 8 - 10 mm. Both the top and bottom of the wavy flow channel are equipped with a plurality of heating rods. The outlet end of the wavy flow channel is provided with a sizing die. The diameter D of the sizing die is 0.7 - 1.2 mm, and the length is 15 - 20D. An internal traction roller is arranged in the sizing die. The internal traction roller is a pair of metal rollers rotating towards each other, driven by a servo motor, used to traction the fiber bundle, and realize the infiltration of the molten resin to the fiber bundle through extrusion. The traction speed of the internal traction roller to the fiber bundle is the same as the wire feeding speed of the 3D printing device.

6. The production system for continuous fiber impregnated reinforced resin 3D printing according to claim 1, characterized in that: The swing device includes a cam, a drive shaft, a coupling and a stepping motor arranged in series. The cam is connected to the drive shaft by a key. The coupling and the drive shaft are driven by the stepping motor to drive the cam to rotate, so that the fiber bundle is disturbed along the direction perpendicular to the fiber dragging direction and the direction parallel to the fiber dragging direction. The cam swing frequency of the swing device is 10 - 20 r / min, and the eccentric amplitude is 10 - 15 mm. The multiple rotating rollers of the pneumatic auxiliary spreading device are driven by a motor. The air flow speed is 2 - 8 m / min. The air flow direction is perpendicular to the conveying direction of the fiber bundle and passes through between the single fibers. The fiber bundle is guided and limited by the multiple rotating rollers.

7. The production system for continuous fiber impregnated reinforced resin 3D printing according to claim 1, characterized in that: The 3D printing device includes a divergent nozzle. The divergence angle of the divergent nozzle is 30 - 60°. The length of the divergent section is 1 - 1.5 times the nozzle flow channel diameter. The outlet of the divergent nozzle is chamfered. The edge width d of the divergent nozzle is 2 - 4 mm.

8. A 3D printing method using a 3D printing production system for continuously fiber-impregnated reinforced resin according to any one of claims 1-7, characterized in that It includes the following steps: (1) After the continuous fiber bundle is unrolled by the unrolling roller device, it first passes through the pre-tensioning device for pre-dispersion, and then the upper and lower surfaces of the continuous fiber bundle are preheated by the infrared radiation device. The preheating temperature is 100 - 200 °C; (2) Let the preheated continuous fiber bundle pass through the swing device. The swing device makes the continuous fiber disturbed along the direction perpendicular to the fiber dragging direction and the direction parallel to the fiber dragging direction through the eccentric rotation of the cam. The pneumatic auxiliary spreading device provides air flow to the continuous fiber bundle. The air flow direction is perpendicular to the conveying direction of the fiber bundle. Under the action of the initial fiber, the air flow speed on both sides of the fiber is greater than the air flow blocked by the fiber in the middle, so that the pressure on both sides is lower. Under the action of the air pressure, the fiber bundle begins to gradually expand to both sides, so that the fiber bundle is split. The final expanded width of the fiber bundle is 15 - 25 mm, and the thickness is 0.03 - 0.06 mm; (3) The screw extrusion device melts and plasticizes the resin raw material and feeds it into the wire infiltration device, and introduces the expanded fiber bundle into the wire infiltration device. Under the action of the wavy flow channel, the infiltration process of the resin matrix to the fiber bundle is completed. The infiltrated fiber is conveyed forward by the internal traction roller, formed through a circular sizing die, and then cooled and shaped by the cooling device. The shaped wire is a continuous fiber prepreg that can be used for 3D printing, with a diameter of 0.7 - 1.2 mm; (4)Cool the obtained continuous fiber prepreg wire, and then convey it to the divergent nozzle of the 3D printer through the wire feeding mechanism of the 3D printing device for 3D printing and forming, and finally obtain a 3D printed product with continuous fiber impregnated and reinforced resin.

9. The 3D printing method according to claim 8, wherein: The continuous fiber is glass fiber or carbon fiber; The resin used is at least one of polylactic acid, nylon, polyphenylene sulfide or polyether ether ketone.

10. The 3D printing method according to claim 8, wherein: In step (3), the amount of continuous fiber in the continuous fiber prepreg wire that can be used for 3D printing is 10-30% of the mass of the melt after melting and plasticizing in the screw extrusion device.

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