Production system and method for continuous fiber impregnated reinforced resin 3D printing

Abstract

The invention belongs to the field of composite material manufacturing, and discloses a continuous fiber impregnation reinforced resin 3D printing integrated device and method. The continuous fiber impregnation reinforced resin 3D printing production system sequentially comprises a pre-tensioning device, an infrared radiation device, a swing device, a pneumatic auxiliary spreading device, a wire impregnation device, a screw extrusion device and a 3D printing device. The feeding direction of the infiltrating chamber is roughly parallel to the feeding direction of the plastic melt conveying chamber, namely, the screw extrusion device is also roughly parallel to the wire infiltrating device. According to the screw extrusion device, a conventional screw with a small thread pitch is not used in a vacuum exhaust section, a screw with a large thread pitch is used, and the thread pitch is 1.5 D-2D (D is the inner diameter of a charging barrel). By optimizing the structure of the device, the defects that continuous fibers are easy to break and resin is easy to carbonize are reduced, the yield of products is improved, and stable production is realized.

Description

Technical Field

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

[0002] Using continuous fiber to reinforce thermoplastic resin for 3D printing is a current research hotspot, and the main purpose is to significantly improve the strength of 3D printing materials. The main method used is to directly introduce the continuous fiber bundle into the nozzle of the printer, and the continuous fiber bundle and the 3D printing filament are printed through the nozzle of the printer at the same time. The main defect of this technology is that the interface bonding between the continuous fiber and the thermoplastic resin matrix is ​​relatively poor, and the fiber bundle is not fully impregnated. This is mainly due to the small and short flow channel in the nozzle of the 3D printer, the short residence time of the material in the nozzle, and the lack of sufficient molding pressure, resulting in poor impregnation effect of the resin matrix on the fiber bundle. This will not give full play to the reinforcing effect of continuous fibers on composite products. There are patents and commercial technologies that use prepreg tanks to pre-impregnate continuous fibers to improve interface bonding, but this method has low production efficiency. The existing patent disclosure text CN 111186138 A discloses a 3D printing device for continuous fiber melt impregnation, which can better solve the problem of balancing the interface bonding force and production efficiency between the continuous fiber and the thermoplastic resin matrix.

[0003] In order to further improve production efficiency, the inventors tried to combine a twin-screw extruder with an existing device. However, during testing, it was found that when a conventional twin-screw extruder was combined with an existing continuous fiber melt impregnation 3D printing device, fiber breakage was prone to occur. During long-term production, resin degradation and carbonization were also prone to occur in the impregnation mold, affecting production stability and product quality. Summary of the invention

[0004] In order to overcome the shortcomings and deficiencies of the above-mentioned prior art, the purpose of the present invention is to provide a production system and method for continuous fiber impregnation reinforced resin 3D printing, so as to realize one-step molding from resin modification to 3D printing. The resin has excellent performance, good fiber continuity, good interface bonding between the fiber and the resin matrix, and the fiber is fully dispersed, and 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 through the following solutions: A production system for continuous fiber impregnation reinforced resin 3D printing, comprising: a pre-tensioning device, which has a plurality of staggered tensioning rollers for pre-dispersing continuous fiber bundles; an infrared radiation device, which is used to preheat the pre-dispersed continuous fiber bundles; a swinging device, which is located downstream of the infrared radiation device and is used to disturb the preheated continuous fiber bundles along a direction perpendicular to the fiber dragging direction and a direction parallel to the fiber dragging direction; a pneumatic auxiliary spreading device, which is located downstream of the swinging device and has a plurality of rotating rollers for conveying the continuous fiber bundles, and has an airflow input port on the top thereof, which is used to spray high-pressure gas to make the continuous fiber bundles A continuous fiber bundle is spread out; a wire impregnation device, the wire impregnation device includes an impregnation chamber and a plastic melt conveying chamber arranged up and down, the impregnation chamber is used to mix and impregnate 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 is parallel to the feeding direction of the plastic melt conveying chamber; a screw extruder, which is used to melt-mix resin raw materials to obtain a plastic melt and is connected to the plastic melt conveying chamber; a 3D printing device, the 3D printing device is located downstream of the wire impregnation device, and is used to heat, eject and 3D print the impregnated fibers to obtain a 3D printed product of a continuous fiber reinforced thermoplastic composite material.

[0006] Preferably, the screw extrusion device is a twin-screw extruder, which includes a barrel, one end of the barrel has a feed port, the other end of the barrel has a discharge port, 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 of the vacuum exhaust section no longer uses a screw with a smaller thread pitch, but a screw with a larger thread pitch, the thread pitch of the vacuum exhaust section is 1.5D-2D, 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 aspect ratio is 40-60, and the screw speed is 0-500rpm / min.

[0007] Preferably, a cooling device is further arranged between the wire impregnation device and the 3D printing device, and the cooling device is used to cool and shape the impregnated fibers.

[0008] Preferably, a pay-off roller device for winding the continuous fiber bundle is further arranged upstream of the pre-tensioning device.

[0009] Preferably, a fluid channel is provided in the plastic melt conveying chamber, and the fluid channel is provided with a plurality of corners to form a curved path inside the plastic melt conveying chamber, wherein the cross-section of the plastic melt conveying chamber along the length direction of the wire infiltration device is square, the side length of the square is L, the number of the corners is three, namely R1, R2, and R3, the radius of curvature of R1 is 0.1L-0.3L, the radius of curvature of R2 is 0.1L-0.3L, and the radius of curvature of R3 is 0.8L-1.2L.

[0010] Preferably, a wavy flow channel is arranged in the impregnation chamber, the covering angle of the wavy flow channel is 300°-450°, the gap of the wavy flow channel is 8~10mm, a plurality of heating rods are arranged at the top and bottom of the wavy flow channel, a shaping die is arranged at the outlet end of the wavy flow channel, the diameter D of the shaping die is 0.7-1.2mm, and the length is 15~20D, an inner traction roller is arranged in the shaping die, the inner traction roller is a pair of metal rollers rotating in opposite directions, driven by a servo motor, and used for traction of fiber bundles, and the molten resin is infiltrated into the fiber bundles through extrusion, and the traction speed of the inner traction roller on the fiber bundle is the same as the wire feeding speed of the 3D printing device.

[0011] Preferably, the swing device includes a cam, a drive shaft, a coupling and a stepper motor arranged in series, the cam is connected to the drive shaft by a key, and the coupling and the drive shaft are driven by the stepper 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 10-20r / min, and the eccentric amplitude is 10-15mm; the multiple rotating rollers of the pneumatic auxiliary spreading device are driven by a motor, and the air flow speed is 2-8m / min. The air flow direction is perpendicular to the conveying direction of the fiber bundle and passes through between the fiber filaments. The fiber bundle is guided and limited by the multiple rotating rollers.

[0012] Preferably, the 3D printing device comprises 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, and the edge width d of the divergent nozzle is 2-4 mm.

[0013] A 3D printing method for a production system of continuous fiber impregnation reinforced resin 3D printing, comprising the following steps: (1) After the continuous fiber bundle is unwound by the unwinding roller 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 at a preheating temperature of 100-200°C; (2) The preheated continuous fiber bundle is passed through a swinging device, wherein the swinging device disturbs the continuous fibers along the direction perpendicular to and parallel to the fiber dragging direction through the eccentric rotation of the cam, and the pneumatic auxiliary spreading device provides airflow to the continuous fiber bundle, and the airflow direction is perpendicular to the conveying direction of the fiber bundle. Under the action of the initial fibers, the airflow speed on both sides of the fibers is greater than the airflow blocked by the fibers 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 spread to both sides, so that the fiber bundle is split, and the final spread width of the fiber bundle is 15-25 mm and the thickness is 0.03-0.06 mm; (3) The screw extruder melts and plasticizes the resin raw material and feeds 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 impregnates the fiber bundle. The impregnated fiber is transported forward by the inner traction roller, formed by a circular shaping die, and then cooled and shaped by a 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) After the obtained continuous fiber prepreg is cooled, it is transported to the divergent nozzle of the printer through the wire feeding mechanism of the 3D printing device for 3D printing, and finally a 3D printed product of continuous fiber impregnated with reinforced resin is obtained.

[0014] Preferably, the continuous fiber is glass fiber or carbon fiber; and the resin used is at least one of polylactic acid, nylon, polyphenylene sulfide or polyetheretherketone.

[0015] Preferably, the amount of continuous fiber in the continuous fiber prepreg that can be used for 3D printing in step (3) is 10-30% of the mass of the melt after melt plasticization in the screw extruder, preferably 20%.

[0016] Preferably, in addition to the resin, at least one of an antioxidant and a lubricant may be added to the resin raw material in step (3).

[0017] Preferably, the printing temperature of the 3D printing in step (4) is 200-400° C., and the printing speed is 50-1000 mm / min.

[0018] Compared with the prior art, the production system of continuous fiber impregnation reinforced resin 3D printing of the present invention has the following beneficial effects: the plastic melt is modified by a screw extruder, and continuous fiber impregnation reinforcement and 3D printing are effectively combined to achieve integrated production. The transfer link between resin modification to continuous fiber impregnation and 3D printing is avoided, and the production efficiency of the product is improved. At the same time, by optimizing the device structure, the shortcomings of easy breakage of continuous fibers and easy carbonization of resins are reduced, the yield of the product is improved, and stable production is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of a production system for continuous fiber impregnation reinforced resin 3D printing of the present invention.

[0020] Figure 2 It is a three-dimensional structural schematic diagram of the screw extrusion device and the wire material infiltration device of the present invention.

[0021] Figure 3 It is a partial cross-sectional view of the screw extrusion device and the wire material impregnation device of the present invention.

[0022] Figure 4 It is a structural schematic diagram of the swing device of the present invention.

[0023] Figure 5 It is a top view of the pneumatic assisted expansion device of the present invention.

[0024] Among them, 1-unwinding roller device, 2-pre-tensioning device, 201-tensioning roller, 3-infrared radiation device, 4-swinging device, 401-cam, 402-drive shaft, 403-coupling, 404-stepping motor, 5-pneumatic auxiliary expansion device, 501-rotating roller, 6-wire infiltration device, 6a-infiltration chamber, 6b-plastic melt conveying chamber, 601-wavy flow channel, 602-heating rod, 603-forming die, 604-inner traction roller, 7-screw extrusion device, 8-cooling device, 9-3D printing device, 901-divergent nozzle, 902-traction roller. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below in conjunction with examples and drawings, but the embodiments of the present invention are not limited thereto. PA6 used in the examples is BASF Ultramid B3S, PA6 / 66 (80 / 20) is BASF Ultramid B33SLX 09, PA12 is Grilamid L25 of EMS, PA106 is Chendong HPANX6HF, and carbon fiber is Zhongfu Shenying SYT45.

[0026] The tensile strength and bending strength in the examples refer to ISO527 standard, and the interlaminar shear sample refers to JC / T773-2010 standard. Five samples are tested for each group of samples and the average value is taken.

[0027] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. If the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0028] like Figure 1As shown, a production system for continuous fiber impregnation reinforced resin 3D printing includes a reel 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 in sequence, and the overall layout is in a strip shape.

[0029] like Figure 1 As shown, the pre-tensioning device 2 has a plurality of staggered tensioning rollers 201 for pre-dispersing the continuous fiber bundle. In the present embodiment, there are three tensioning rollers 201, which are staggered so that the conveying path of the continuous fiber bundle is wavy.

[0030] like Figure 1 As shown, the infrared radiation device 3 is used to preheat the pre-dispersed continuous fiber bundle, wherein 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 therebetween.

[0031] like Figure 1 , Figure 4 and Figure 5 As shown, the swing device 4 is located downstream of the infrared radiation device 3, and is used to disturb the preheated continuous fiber bundle along the direction perpendicular to the fiber dragging direction and the direction parallel to the fiber dragging direction. The pneumatic auxiliary spreading device 5 is located downstream of the swing device 4, and has a plurality of rotating rollers 501 for conveying the continuous fiber bundle, and has an airflow input port at the top, and the continuous fiber bundle is separated and spread out by high-pressure gas blowing. The swing device 4 includes a cam 401, a drive shaft 402, a coupling 403 and a stepper motor 404 arranged in series. The cam 401 is connected to the drive shaft 402 by a key. The coupling 403 and the drive shaft 402 are driven by the stepper motor 404 to drive the cam 401 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, thereby 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, which is convenient for subsequent yarn spreading. The swing frequency of the cam 401 of the swing device 4 is 10-20r / min, and the eccentric amplitude is 10-15mm; the multiple rotating rollers 501 of the pneumatic auxiliary spreading device 5 are driven by a motor, the air flow speed is 2-8m / min, the air flow direction is perpendicular to the conveying direction of the fiber bundle, and passes through between the fiber filaments, which can effectively avoid fiber damage, and the fiber bundle is guided and limited by the multiple rotating rollers 501. There are three rotating rollers 501, including two guide rollers and one limiting roller. The position of the limiting roller can be adjusted up and down. After the yarn is spread by the pneumatic auxiliary spreading device 5, the width of a single bundle of fibers is 15-25mm and the thickness is 0.03-0.06mm.

[0032] like Figure 1-3 As shown, 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 conveying chamber 6b arranged up and down. The impregnation chamber 6a is used to mix and impregnate the continuous fiber bundle from the pneumatic auxiliary spreading device 5 with the plastic melt conveyed by the plastic melt conveying chamber 6b to obtain impregnated fibers; wherein the feeding direction of the impregnation chamber 6a and the feeding direction of the plastic melt conveying chamber 6b are roughly parallel. A fluid channel is arranged in the plastic melt conveying chamber 6b, and the fluid channel is provided with a plurality of corners to form a curved path inside the plastic melt conveying chamber 6b, wherein the cross section of the plastic melt conveying chamber 6b along the length direction X of the wire infiltration 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 arranged in the impregnation chamber 6a, the covering angle of the wavy flow channel 601 is 300°-450°, the gap of the wavy flow channel 601 is 8~10mm, a plurality of heating rods 602 are arranged at the top and bottom of the wavy flow channel 601, a shaping die 603 is arranged at the outlet end of the wavy flow channel 601, the diameter D of the shaping die 603 is 0.7-1.2mm, and the length is 15~20D, an inner traction roller 604 is arranged in the shaping die 603, the inner traction roller 604 is a pair of metal rollers rotating in opposite directions, driven by a servo motor, and used for traction of fiber bundles, and realizing the infiltration of the fiber bundles by the molten resin through the extrusion action, and the traction speed of the inner traction roller 604 on the fiber bundle is the same as the wire feeding speed of the 3D printing device 9.

[0033] like Figure 1 and Figure 3As shown, the screw extrusion device 7 is used to melt the resin raw material to obtain a plastic melt, and is connected to the fluid channel of the plastic melt conveying chamber 6b. The screw extrusion device 7 is connected in parallel with the wire impregnation device 6. The screw extrusion device 7 is a twin-screw extruder, which includes a barrel, one end of the barrel has a feed port, and the other end of the barrel has a discharge port. 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 of 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, and the thread pitch of the melting section is 1D-2D. The thread pitch of the screw extruder 7 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 diameter of the screw extruder 7 is 18mm-90mm, the aspect ratio is 40-60, the screw speed is 0-500rpm / min, the resin raw material enters from the feed port, and the plastic melt is discharged from the discharge port and conveyed to the plastic melt conveying chamber 6b through the turning, mixing and conveying of the twin screws, wherein the vacuum exhaust section is used to exhaust and extract the gas in the barrel to prevent the gas from entering the plastic melt conveying chamber 6b.

[0034] like Figure 1 As shown, a 3D printing device 9 is located downstream of the wire impregnation device 6, and is used to heat and spray 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 2-4mm. It can ensure that the nozzle edge has a larger contact area with the surface of the product during the printing process, 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, which is used to guide the continuous fiber cooled by the cooling device 8 into the 3D printing device.

[0035] like Figure 1 As shown, a cooling device 8 is further arranged between the wire impregnation device 6 and the 3D printing device 9, and the cooling device 8 is used to cool and shape the impregnated fibers; a reel device 1 for winding a continuous fiber bundle is also arranged upstream of the pre-tensioning device 2.

[0036] In an embodiment not shown, the number of wire impregnation devices 6 can be configured as needed, and the multiple wire impregnation devices 6 are arranged side by side at a certain interval. The continuous fiber bundles after being spread by the pneumatic auxiliary spreading device 5 are respectively transported to the multiple wire impregnation devices 6, so that multiple wires can be impregnated at the same time, thereby improving production efficiency.

[0037] A 3D printing method of a production system for continuous fiber impregnation reinforced resin 3D printing includes the following steps.

[0038] (1) After the continuous fiber bundle is unwound by the unwinding roller device 1, it is first pre-dispersed by the pre-tensioning device 2, 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.

[0039] (2) The preheated continuous fiber bundle is passed through the swing device 4, wherein the swing device 4 disturbs the continuous fibers along the direction perpendicular to and parallel to the fiber dragging direction through the eccentric rotation of the cam 401. The pneumatic auxiliary spreading device 5 provides airflow to the continuous fiber bundle, and the airflow direction is perpendicular to the conveying direction of the fiber bundle. Under the action of the initial fibers, the airflow speed on both sides of the fibers is greater than the airflow blocked by the fibers in the middle, thereby making the pressure on both sides 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.

[0040] (3) The screw extruder 7 melts and plasticizes the resin raw material and feeds it to 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 resin matrix impregnates the fiber bundle. The impregnated fiber is transported forward by the inner traction roller 604, formed by 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.

[0041] (4) After the obtained continuous fiber prepreg is cooled, it is transported to the divergent nozzle of the printer through the wire feeding mechanism of the 3D printing device 9 for 3D printing and molding, and finally a 3D printed product of continuous fiber impregnated with reinforced resin is obtained.

[0042] The continuous fibers are glass fibers or carbon fibers; the resin used is at least one of polylactic acid, nylon, polyphenylene sulfide or polyetheretherketone.

[0043] The amount of continuous fiber in the continuous fiber prepreg that can be used for 3D printing in step (3) is 10-30% of the mass of the melt after melt plasticization in the screw extruder 7, preferably 20%.

[0044] In addition to the resin, at least one of an antioxidant and a lubricant may be added to the resin raw material in step (3).

[0045] The printing temperature of the 3D printing in step (4) is 200-400° C., and the printing speed is 50-1000 mm / min.

[0046] Example 1 A 3D printing method of a production system of continuous fiber impregnation reinforced resin 3D printing of the present invention is adopted, wherein the parameters are: the wrapping angle of the wavy flow channel 601 in the wire impregnation device 6 is 350°, the flow channel gap is 10mm, the traction speed of the inner traction roller 604 is 5m / min, the diameter D of the shaping die 603 is 1mm, and the length is 15 times the diameter D. The cam 401 in the swing device 4 has a swing frequency of 12r / min and an eccentric amplitude of 10mm. The air flow speed of the air-assisted device is 5m / min, the width of a single fiber bundle after being spread by the pneumatic auxiliary spreading device 5 is 20mm, and the thickness is 0.05mm, the preheating temperature of the infrared radiation device 3 is 180°C, the diameter of the shaping die 603 is 1mm, and the diameter of the obtained continuous fiber prepreg is 1mm. The divergence angle α of the divergent nozzle of the 3D printing device 9 is 60°, the divergent section length is 1.2 times the divergent nozzle flow channel diameter, the divergent nozzle edge width d is 3mm, the printing temperature is 280°C, and the printing rate is 120mm / min. The screw extruder 7 adopts a twin-screw extruder with a screw diameter of 18mm, an aspect ratio of 48, a screw speed of 150rpm / min, a processing temperature of 260°C, a solid conveying section adopts 3 screw elements with a thread pitch of 1D and 3 screw elements with a thread pitch of 2D, a melting section adopts 1 screw element with a thread pitch of 0.5D and 4 screw elements with a thread pitch of 1D, a melt conveying section adopts 4 screw elements with a thread pitch of 1D, and a vacuum exhaust section adopts a screw section composed of 2 screw elements of 2D. R1=0.1L, R2=0.1L, and R3=1L of the plastic melt conveying chamber 6b. The fiber bundle is carbon fiber, and the amount of carbon fiber used is 20% of the weight of the modified resin; the modified resin used is modified nylon 6, and has the following weight percentage formula: PA6 79.4%; PA6 / 66 (80 / 20) 20%; Antioxidant 1098 0.3%; Lubricant EBS 0.3%.

[0047] Comparative Example 1 is a modified resin prepared by using the device in the patent publication CN 111186138 A, the parameters of which are: the wrapping angle of the wavy flow channel 601 in the wire impregnation device 6 is 350°, the flow 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 15 times the diameter D. The cam 401 in the swing device 4 has a swing frequency of 12 r / min and an eccentric amplitude of 10 mm. The airflow velocity of the pneumatic auxiliary spreading device 5 is 5 m / min, the width of a single fiber bundle after being spread 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 obtained continuous fiber prepreg is 1 mm. The divergence angle α of the divergent nozzle of the 3D printing device 9 is 60°, the divergent section length is 1.2 times the divergent nozzle flow channel diameter, the divergent nozzle edge width d is 3mm, the printing temperature is 280°C, and the printing rate is 120mm / min. The screw extruder 7 adopts a twin screw, the screw diameter is 18mm, the aspect ratio is 48, the screw speed is 150rpm / 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 segment composed of 2 screw elements of 0.75D + 4 screw elements of 0.5D. The screw extruder 7 is connected to the wire infiltration device 6 at right angles, that is, the feeding direction of the screw extruder 7 is perpendicular to the feeding direction of the wire infiltration device 6.

[0048] That is, the only difference between Comparative Example 1 and Example 1 is that a conventional twin-screw combination is used in Comparative Example 1, that is, the vacuum exhaust section adopts a screw segment composed of 2 pieces of 0.75D + 4 pieces of 0.5D threaded elements, 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 adopts a screw segment composed of 2 pieces of 2D threaded elements, and the screw extrusion device 7 is connected to the wire impregnation device 6 in parallel, and R1=0.1L, R2=0.1L, and R3=1L of the plastic melt conveying chamber 6b.

[0049] Table 1 Performance comparison between Comparative Example 1 and Example 1.

[0050] Example 2 A 3D printing method of a production system of continuous fiber impregnation reinforced resin 3D printing of the present invention is adopted, wherein the parameters are: the wrapping angle of the wavy flow channel 601 in the wire impregnation device 6 is 400°, the flow channel gap is 8mm, the traction speed of the inner traction roller 604 is 4m / min, the diameter D of the shaping die 603 is 0.8mm, and the length is 20 times the diameter D. The cam 401 in the swing device 4 has a swing frequency of 12r / min and an eccentric amplitude of 10mm. The air flow speed of the air-assisted device is 5m / min, the width of a single fiber bundle after being spread by the pneumatic auxiliary spreading device 5 is 20mm, and the thickness is 0.05mm, the preheating temperature of the infrared radiation device 3 is 180°C, the diameter of the shaping die 603 is 0.8mm, and the diameter of the obtained continuous fiber prepreg is 0.8mm. The divergence angle α of the divergent nozzle of the 3D printing device 9 is 60°, the divergent section length is 1.2 times the divergent nozzle flow channel diameter, the divergent nozzle edge width d is 3mm, the printing temperature is 270°C, and the printing rate is 150mm / min. The screw extruder 7 adopts a twin screw, the screw diameter is 18mm, the aspect ratio is 48, the screw speed is 200rpm / min, the processing temperature is 240C, 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 twin screw vacuum exhaust section adopts 3 conveying screw elements with a thread pitch of 1.5D. R1=0.2L, R2=0.2L, and R3=0.9L of the plastic melt conveying chamber 6b. The fiber bundle is carbon fiber, and the modified resin used is modified nylon 12, having the following weight percentage formula: PA12 84.4%; PA6 15%; Antioxidant 1098 0.3%; Lubricant EBS 0.3%.

[0051] Comparative Example 2 is a modified resin prepared by an existing continuous fiber melt impregnation 3D printing device, the same as Example 2, wherein the parameters are: the wrapping angle of the wavy flow channel 601 in the wire impregnation device 6 is 400°, the flow channel gap is 8mm, the traction speed of the inner traction roller 604 is 4m / min, the diameter D of the shaping die 603 is 0.8mm, and the length is 20 times the diameter D. The cam 401 in the swing device 4 has a swing frequency of 12r / min and an eccentric amplitude of 10mm. The airflow velocity of the pneumatic auxiliary spreading device 5 is 5m / min, the width of a single fiber bundle after the pneumatic auxiliary spreading device 5 is 20mm, and the thickness is 0.05mm, the preheating temperature of the infrared radiation device 3 is 180°C, the diameter of the shaping die 603 is 0.8mm, and the diameter of the obtained continuous fiber prepreg is 0.8mm. The divergence angle α of the divergent nozzle of the 3D printing device 9 is 60°, the divergent section length is 1.2 times the divergent nozzle flow channel diameter, the divergent nozzle edge width d is 3mm, the printing temperature is 270°C, and the printing rate is 150mm / min. The screw extruder 7 adopts a twin screw, the screw diameter is 18mm, the aspect ratio is 48, the screw speed is 200rpm / min, the processing temperature is 240°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 segment composed of 2 screw elements of 0.75D + 4 screw elements of 0.5D. The screw extruder 7 is connected to the wire infiltration device 6 at right angles, that is, the feeding direction of the screw extruder 7 is perpendicular to the feeding direction of the wire infiltration device 6.

[0052] That is, the only difference between Comparative Example 2 and Example 2 is that a conventional twin-screw combination is used in Comparative Example 2, that is, the vacuum exhaust section adopts a screw segment composed of 2 pieces of 0.75D + 4 pieces of 0.5D threaded elements, and the screw extruder 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 adopts a screw segment composed of 3 pieces of 1.5D threaded elements, and the screw extruder 7 is connected to the wire impregnation device 6 in parallel, and R1=0.2L, R2=0.2L, and R3=0.9L of the plastic melt conveying chamber 6b.

[0053] Table 2 Performance comparison between Comparative Example 2 and Example 2.

[0054] Example 3 A 3D printing method of a production system of continuous fiber impregnation reinforced resin 3D printing of the present invention is adopted, wherein the parameters are: the wrapping angle of the wavy flow channel 601 in the wire impregnation device 6 is 320°, the flow channel gap is 8mm, the traction speed of the inner traction roller 604 is 5m / min, the diameter D of the shaping die 603 is 1.1mm, and the length is 15 times the diameter D. The cam 401 in the swing device 4 has a swing frequency of 10r / min and an eccentric amplitude of 12mm. The airflow velocity of the pneumatic auxiliary spreading device 5 is 4m / min, the width of a single fiber bundle after the pneumatic auxiliary spreading device 5 is 20mm, and the thickness is 0.05mm, the preheating temperature of the infrared radiation device 3 is 150℃, the diameter of the shaping die 603 is 1.1mm, and the diameter of the obtained continuous fiber prepreg is 1.1mm. The divergence angle α of the divergent nozzle of the 3D printing device 9 is 60°, the divergent section length is 1.2 times the divergent nozzle flow channel diameter, the divergent nozzle edge width d is 3mm, the printing temperature is 285°C, and the printing rate is 180mm / min. The screw extruder 7 adopts a twin screw, the screw diameter is 18mm, the aspect ratio is 48, the screw speed is 200rpm / 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 twin screw vacuum exhaust section adopts a screw section composed of 5 screw elements with a thread pitch of 1.5D. Plastic melt conveying chamber 6b R1=0.2L, R2=0.2L, R3=0.9L. The fiber bundle is carbon fiber, and the modified resin used is modified nylon 106, having the following weight percentage formula: PA106 79.4%; PA6 20%; Antioxidant 1098 0.3%; Lubricant EBS 0.3%; Comparative Example 3 is a modified resin prepared by an existing continuous fiber melt impregnation 3D printing device, wherein the parameters are: the wrapping angle of the wavy flow channel 601 in the wire impregnation device 6 is 320°, the flow channel gap is 8mm, the traction speed of the inner traction roller 604 is 5m / min, the diameter D of the shaping die 603 is 1.1mm, and the length is 15 times the diameter D. The cam 40118 in the swing device 4 has a swing frequency of 10r / min and an eccentric amplitude of 12mm. The airflow velocity of the pneumatic auxiliary spreading device 5 is 4m / min, the width of a single fiber bundle after the pneumatic auxiliary spreading device 5 is 20mm, and the thickness is 0.05mm, the preheating temperature of the infrared radiation device 3 is 150℃, the diameter of the shaping die 603 is 1.1mm, and the diameter of the obtained continuous fiber prepreg is 1.1mm. The divergence angle α of the divergent nozzle of the 3D printing device 9 is 60°, the divergent section length is 1.2 times the divergent nozzle flow channel diameter, the divergent nozzle edge width d is 3mm, the printing temperature is 285°C, and the printing rate is 180mm / min. The screw extruder 7 adopts a twin screw, the screw diameter is 18mm, the aspect ratio is 48, the screw speed is 200rpm / 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 twin screw vacuum exhaust section adopts a screw segment composed of 2 screw elements of 0.75D + 4 screw elements of 0.5D. The screw extrusion device 7 is connected to the wire infiltration 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 infiltration device 6 .

[0055] That is, the only difference between Comparative Example 3 and Example 3 is that a conventional twin-screw combination is used in Comparative Example 3, that is, the vacuum exhaust section adopts a screw segment composed of 2 pieces of 0.75D + 4 pieces of 0.5D threaded elements, and the screw extruder 7 is connected to the wire impregnation device 6 at a right angle; while in Example 3, the twin-screw vacuum exhaust section adopts a screw segment composed of 5 pieces of 1.5D threaded elements, and the screw extruder 7 is connected to the wire impregnation device 6 in parallel, and R1=0.2L, R2=0.2L, and R3=0.9L of the plastic melt conveying chamber 6b.

[0056] Table 3 Performance comparison between Comparative Example 3 and Example 3.

[0057] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A production system for continuous fiber impregnation reinforced resin 3D printing, characterized in that: include: A pre-tensioning device having a plurality of staggered tensioning rollers for pre-dispersing the continuous fiber bundle; An infrared radiation device, wherein the infrared radiation device is used to preheat the pre-dispersed continuous fiber bundle; A swing device, the swing device is located downstream of the infrared radiation device, and is used to disturb the preheated continuous fiber bundle along a direction perpendicular to the fiber dragging direction and a direction parallel to the fiber dragging direction; A pneumatic assisted spreading device, the pneumatic assisted spreading device is located downstream of the swing device, the pneumatic assisted spreading device has a plurality of rotating rollers for conveying the continuous fiber bundle, and the top of the pneumatic assisted spreading device has an airflow inlet, and the continuous fiber bundle is spread out by high-pressure gas blowing; A wire impregnation device, the wire impregnation device comprises an impregnation chamber and a plastic melt conveying chamber arranged up and down, the impregnation chamber is used to mix and impregnate 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 is parallel to the feeding direction of the plastic melt conveying chamber; A screw extruder, which is used to melt the resin raw material to obtain a plastic melt and is connected to the plastic melt conveying chamber; A 3D printing device is located downstream of the wire impregnation device and is used to heat, spray and 3D print the impregnated fibers to obtain a 3D printed product of a continuous fiber reinforced thermoplastic composite material.

2. A continuous fiber impregnation reinforced resin 3D printing production system according to claim 1, characterized in that: The screw extruder is a twin-screw extruder, which includes a barrel, one end of the barrel has a feed port, the other end of the barrel has a discharge port, 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 thread pitch of the vacuum exhaust section is 1.5D-2D, D is the inner diameter of the barrel; the screw diameter of the screw extruder is 18mm-90mm, the aspect ratio is 40-60, and the screw speed is 0-500rpm / min.

3. A continuous fiber impregnation reinforced resin 3D printing production system according to claim 1, characterized in that: A cooling device is also arranged between the wire impregnation device and the 3D printing device, and the cooling device is used to cool and shape the impregnated fibers; a reel device for winding a continuous fiber bundle is also arranged upstream of the pre-tensioning device.

4. A continuous fiber impregnation reinforced resin 3D printing production system according to claim 1, characterized in that: A fluid channel is arranged in the plastic melt conveying chamber, and the fluid channel is provided with a plurality of corners to form a curved path inside the plastic melt conveying chamber, wherein the cross section of the plastic melt conveying chamber along the length direction of the wire infiltration device is square, and the side length of the square is L. There are three corners, namely R1, R2, and R3, and 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.

5. The continuous fiber impregnation reinforced resin 3D printing production system according to claim 1, characterized in that: A wavy flow channel is arranged in the impregnation chamber, the covering angle of the wavy flow channel is 300°-450°, the gap of the wavy flow channel is 8~10mm, a plurality of heating rods are arranged at the top and bottom of the wavy flow channel, a shaping die is arranged at the outlet end of the wavy flow channel, the diameter D of the shaping die is 0.7-1.2mm, and the length is 15~20D, an inner traction roller is arranged in the shaping die, the inner traction roller is a pair of metal rollers rotating in opposite directions, driven by a servo motor, and used for traction of fiber bundles, and the molten resin is infiltrated into the fiber bundles through extrusion, and the traction speed of the inner traction roller on the fiber bundles is the same as the wire feeding speed of the 3D printing device.

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

7. A continuous fiber impregnation reinforced resin 3D printing production system according to claim 1, characterized in that: The 3D printing device comprises 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, and the edge width d of the divergent nozzle is 2-4 mm.

8. A 3D printing method using a continuous fiber impregnated reinforced resin 3D printing production system according to any one of claims 1 to 7, characterized in that The following steps are involved: (1) After the continuous fiber bundle is unwound by the unwinding roller 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 at a preheating temperature of 100-200°C; (2) The preheated continuous fiber bundle is passed through a swinging device, wherein the swinging device disturbs the continuous fibers along the direction perpendicular to and parallel to the fiber dragging direction through the eccentric rotation of the cam, and the pneumatic auxiliary spreading device provides airflow to the continuous fiber bundle, and the airflow direction is perpendicular to the conveying direction of the fiber bundle. Under the action of the initial fibers, the airflow speed on both sides of the fibers is greater than the airflow blocked by the fibers 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 spread to both sides, so that the fiber bundle is split, and the final spread width of the fiber bundle is 15-25 mm and the thickness is 0.03-0.06 mm; (3) The screw extruder melts and plasticizes the resin raw material and feeds 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 impregnates the fiber bundle. The impregnated fiber is transported forward by the inner traction roller, formed by a circular shaping die, and then cooled and shaped by a 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) After the obtained continuous fiber prepreg is cooled, it is transported to the divergent nozzle of the printer through the wire feeding mechanism of the 3D printing device for 3D printing, and finally a 3D printed product of continuous fiber impregnated with reinforced resin is obtained.

9. The 3D printing method according to claim 8, characterized in that: The continuous fibers are glass fibers or carbon fibers; The resin used is at least one of polylactic acid, nylon, polyphenylene sulfide or polyetheretherketone.

10. The 3D printing method according to claim 8, characterized in that: In step (3), the amount of continuous fiber in the continuous fiber prepreg that can be used for 3D printing is 10-30% of the mass of the melt after melt plasticization in the screw extruder.

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