Continuous carbon fiber composite prepreg filament forming method and device for 3D printing

Abstract

The invention relates to a continuous carbon fiber composite prepreg filament forming device for 3D printing. The continuous carbon fiber composite prepreg filament forming device is characterized in that a carbon fiber filament bundle sequentially passes through a fiber unwinding device, an airflow broadening device, a resin powder dipping device, a high-temperature drying device, a filament shaping device, a filament shaping device, a cooling device and a winding device. The invention further relates to a continuous carbon fiber composite material prepreg filament forming method for 3D printing. The resin infiltration uniformity is improved, and fiber damage is reduced.

Description

Technical Field

[0001] The present invention belongs to the field of composite material processing and forming, and specifically relates to the field of preparation of continuous carbon fiber composite prepreg filaments for 3D printing. Background Art

[0002] With the development of 3D printing technology, it shows great advantages in the manufacture of complex structures and personalized products. However, traditional 3D printing materials such as PLA and ABS resins are difficult to meet the requirements for applications in aerospace and other fields due to their own characteristics in terms of mechanical properties, heat resistance, corrosion resistance, etc. Carbon fiber has excellent properties such as high strength, high modulus, low density, high temperature resistance, and corrosion resistance, and is an ideal reinforcing material for manufacturing high-performance composite materials. Combining carbon fiber with resin can prepare carbon fiber reinforced composite materials with excellent properties. In order to meet the further application of 3D printing technology in the aerospace field, the 3D printing of carbon fiber composite materials has become a current research hotspot. However, before the 3D printing of carbon fiber composite materials, the preparation of continuous carbon fiber composite prepreg filaments faces many challenges, such as the problem of carbon fiber breakage during the prepreg filament preparation process, the problem of uniform wetting of fibers and resin, the problem of filament blockage, etc. These problems all affect the mechanical properties of the prepared prepreg filaments and ultimately affect the performance of 3D printed parts.

[0003] Referring to the existing literature and patents, Patent CN 114179251 B discloses a continuous fiber reinforced thermoplastic composite prepreg filament preparation system and method. This system infiltrates and extrudes ultrasonic-dispersed carbon fiber and molten resin by means of screw extrusion to obtain prepreg filaments. In this way, when the carbon fiber infiltrates with the high-viscosity resin during the screw extrusion process, many process parameters need to be controlled, which has a certain process complexity; Patent CN 118082246 A discloses a core-shell structure continuous fiber composite prepreg filament preparation device and its process. This device first prepares prepreg filaments with a high fiber content and then impregnates molten resin outside the prepreg filaments with a high fiber content to obtain a core-shell structure prepreg filament. Although prepreg filaments more suitable for 3D printing are obtained in this way, the fibers and resin do not come into full and uniform contact, and the mechanical properties of the prepreg filament materials and 3D printed parts may be affected. Summary of the Invention

[0004] The present invention provides a continuous carbon fiber composite prepreg filament forming device for 3D printing, aiming to improve the resin infiltration uniformity and reduce fiber damage. The present invention also provides a continuous carbon fiber composite prepreg filament forming method for 3D printing.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows: A device for forming a continuous carbon fiber composite prepreg filament for 3D printing, characterized in that: The carbon fiber tow sequentially passes through a fiber unwinding device, an air flow broadening device, a resin powder impregnation device, a high-temperature drying device, a filament shaping device, a filament trimming device, a cooling device, and a winding device; The air flow broadening device has two air flow broadening guide rollers, the carbon fiber tow bypasses the two air flow broadening guide rollers, and the air flow broadening fan is aligned with the carbon fiber tow between the two air flow broadening guide rollers; The resin powder impregnation device has a resin powder suspension; The filament shaping device consists of a pair of rotating profiling rollers, each profiling roller has a groove on its outer periphery, a pair of grooves form a gap, and the carbon fiber tow passes through the gap; The filament trimming device consists of a pair of rotating profiling rollers, each profiling roller has a groove on its outer periphery, a pair of grooves form a gap, and the carbon fiber tow passes through the gap; The pair of profiling rollers in the trimming device and the pair of profiling rollers in the shaping device are perpendicular to each other in direction.

[0006] The air flow broadening device has two air flow broadening anti-deviation mechanisms, the air flow broadening guide rollers are located between the two air flow broadening anti-deviation mechanisms, the air flow broadening anti-deviation mechanism has an anti-deviation groove in the form of a through groove, and the carbon fiber tow passes through the anti-deviation groove.

[0007] There are two air flow broadening devices, namely a primary air flow broadening device and a secondary air flow broadening device, and the primary air flow broadening device and the secondary air flow broadening device have the same structure.

[0008] Tension wheels or guide wheels are arranged between the fiber unwinding device, the air flow broadening device, the resin powder impregnation device, the high-temperature drying device, the filament shaping device, the filament trimming device, the cooling device, and the winding device.

[0009] The resin powder impregnation device has three impregnation traction rollers, and the carbon fiber tow bypasses the three impregnation traction rollers.

[0010] The profiling rollers of the filament shaping device and the filament trimming device are both in a heated state.

[0011] The cross-section of the groove opened on the profiling rollers of the filament shaping device and the filament trimming device is semi-circular, and a pair of grooves form a circular gap.

[0012] A method for forming a continuous carbon fiber composite prepreg filament for 3D printing, comprising the following steps: (1) Pass the carbon fiber tow sequentially through a fiber unwinding device, an air flow broadening device, a resin powder impregnation device, a high-temperature drying device, a filament shaping device, a filament trimming device, a cooling device, and a winding device; (2) Add the resin powder suspension into the resin powder impregnation device; start the high-temperature drying device to the set temperature; heat the wire shaping device and the shaping device to the set temperature; start the cooling device; start the air flow broadening fan in the air flow broadening device; start the winding device; (3) The carbon fiber is blown and broadened by the air flow broadening fan in the air flow broadening device; (4) The carbon fiber after being blown by the air flow enters the resin powder suspension, and the resin powder is fully adhered to the surface of each carbon fiber under the action of liquid adsorption force; (5) After impregnation, the carbon fiber and the powdered resin enter the high-temperature drying device to evaporate the liquid moisture on the resin powder and the carbon fiber, and the resin powder is melted at high temperature to further adhere to the surface of the carbon fiber; (6) The resin in the molten state together with the carbon fiber enters the wire shaping device and presents a preliminary pre-impregnated wire shape driven by a pair of heated profiling rollers; (7) The preliminarily formed pre-impregnated wire enters a pair of profiling rollers in the wire shaping device, and the shape of the pre-impregnated wire is further processed into an approximately cylindrical pre-impregnated wire; (8) The obtained pre-impregnated wire enters the cooling device for cooling to prevent the wire from deforming due to contact in the subsequent wire winding stage; (9) The cooled pre-impregnated wire is drawn into the winding device for winding through the traction of the traction counter-rollers.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: 1) By dispersing the carbon fiber through the secondary air flow broadening method and impregnating it with the resin powder suspension, both the damage of the carbon fiber is reduced and the uniformity and sufficiency of the impregnation are ensured; 2) The extrusion of the two pairs of profiling rollers further reduces the porosity of the obtained pre-impregnated wire, and the shape of the pre-impregnated wire is closer to a cylindrical shape more suitable for 3D printing.

[0014] 3) By first fully impregnating the resin powder with the dispersed carbon fiber and then melting and extruding it, the preparation of pre-impregnated wire materials with high mechanical properties and low porosity is realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is the process flow chart of the forming method of the present invention; Figure 2 It is the schematic diagram of the air flow broadening and anti-deviation mechanism of the present invention; Figure 3 It is the sectional view of the shaping device of the present invention; Figure 4 It is the sectional view of the shaping device of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016] The present invention will be further described below in conjunction with specific embodiments and the accompanying drawings.

[0017] As Figure 1 shown: Taking the preparation of continuous carbon fiber reinforced polyether ether ketone (PEEK) prepreg filaments as an example, 3K continuous carbon fibers and PEEK resin powder are selected as the raw materials for the prepreg filaments, and prepreg filaments with a diameter of 0.6 mm are prepared. It can be calculated that the volume fraction of carbon fibers in the prepreg filaments is about 40%. The prepreg filaments with such a fiber volume fraction are more suitable for 3D printing. The air output of the air flow broadening fan is selected to be between 1 and 3 m 3 / min, the nozzle outlet temperature of the air flow broadening fan is set between 60 and 150 °C, the mass fraction of PEEK powder in the resin powder suspension is not less than 10%, the mesh number of the PEEK resin powder is not less than 1000 mesh, the temperature of the high-temperature drying device 17 is set not less than 350 °C, and the temperature of the profiling roller 181 in the wire shaping device 18 and the profiling roller 191 in the wire trimming device 19 is set to 360 °C or above.

[0018] A method and device for forming continuous carbon fiber composite prepreg filaments for 3D printing according to the present invention include a fiber unwinding device, a primary air flow broadening device, a secondary air flow broadening device, a resin powder impregnation device, a high-temperature drying device 17, a wire shaping device 18, a wire trimming device 19, a cooling device 21, and a winding device 24 arranged in sequence.

[0019] The carbon fiber raw material roll 1 formed by winding the carbon fiber tow 3 is installed on the fiber unwinding device.

[0020] There is a first tensioning wheel 2 between the fiber unwinding device and the primary air flow broadening device.

[0021] The primary air flow broadening device is internally provided with a primary air flow broadening pre-deviation prevention mechanism 4 and a primary air flow broadening post-deviation prevention mechanism 7. There are two primary air flow broadening guide rollers 5 between the primary air flow broadening pre-deviation prevention mechanism 4 and the primary air flow broadening post-deviation prevention mechanism 7. The primary air flow broadening fan 6 is aligned with the position between the two primary air flow broadening guide rollers 5.

[0022] The secondary air flow broadening device is internally provided with a secondary air flow broadening pre-deviation prevention mechanism 9 and a secondary air flow broadening post-deviation prevention mechanism 12. There are two secondary air flow broadening guide rollers 10 between the secondary air flow broadening pre-deviation prevention mechanism 9 and the secondary air flow broadening post-deviation prevention mechanism 12. The secondary air flow broadening fan 11 is aligned with the position between the two secondary air flow broadening guide rollers 10.

[0023] As Figure 2As shown, the first-stage air flow broadening front anti-deviation mechanism 4 has an anti-deviation groove 41 in the form of a through groove for the carbon fiber tow 3 to pass through. The first-stage air flow broadening rear anti-deviation mechanism 7, the second-stage air flow broadening front anti-deviation mechanism 9, and the second-stage air flow broadening rear anti-deviation mechanism 12 respectively have anti-deviation grooves with the same structure.

[0024] There is a second tension pulley 8 between the first-stage air flow broadening device and the second-stage air flow broadening device.

[0025] The resin powder impregnation device has a resin powder suspension 14, and there are also three impregnation traction rollers 15 in the resin powder impregnation device.

[0026] There is a first guide wheel 13 between the second-stage air flow broadening device and the resin powder impregnation device.

[0027] There is a second guide wheel 16 between the resin powder impregnation device and the high-temperature drying device 17.

[0028] The high-temperature drying device 17 has a high-temperature drying channel.

[0029] As Figure 1 With Figure 3 As shown, the wire shaping device 18 is composed of a pair of rotating profiling rollers 181 in a heated state. Each profiling roller 181 has a groove 182 with a diameter of 0.6 mm and a semi-circular cross-section on its outer periphery. A pair of grooves 182 with a semi-circular cross-section form a circular gap. The profiling roller 181 is a hot roller. The carbon fiber tow 3 together with the molten PEEK resin thereon passes through the circular gap to obtain a cylindrical filament.

[0030] As Figure 1 With Figure 4 As shown, the wire trimming device 19 is also composed of a pair of rotating profiling rollers 191. Each profiling roller 191 has a groove 192 with a diameter of 0.6 mm and a semi-circular cross-section on its outer periphery. A pair of grooves 192 with a semi-circular cross-section form a circular gap. The cylindrical filament shaped by the wire shaping device 18 passes through the circular gap to be trimmed.

[0031] A pair of profiling rollers 191 in the wire trimming device 19 are the same in shape and size as a pair of profiling rollers 181 in the shaping device 18, but their directions are perpendicular to each other. The purpose is to repair the overflow defects generated on the roller surface of the profiling roller 181 of the wire shaping device 18 during the trimming stage for the pre-impregnated wire after shaping, and further process it into an approximately cylindrical pre-impregnated wire. To reduce frictional damage, the linear speeds of the profiling rollers in the shaping device 18 and the trimming device 19 should be consistent with the traction speed of the pre-impregnated wire.

[0032] There is a third guide wheel 20 between the trimming device 19 and the cooling device 21.

[0033] A third tensioning wheel 22 and a pair of traction rollers 23 are provided between the cooling device 21 and the wire collecting device 24 .

[0034] The parts of all the above devices that come into contact with the carbon fiber must be rounded and smoothed to avoid damage as much as possible during the entire process from unwinding the carbon fiber material roll to collecting the prepreg after molding.

[0035] In actual work: A method for forming a continuous carbon fiber composite material prepreg for 3D printing, comprising the following steps: (1) The carbon fiber tow is sequentially passed through a fiber unwinding device 1, a primary airflow widening device, a secondary airflow widening device, a resin powder impregnation device, a high temperature drying device 17, a wire shaping device 18, a wire shaping device 19, a cooling device 21, and a winding device 24; (2) adding the resin powder suspension 14 to the resin powder impregnation device; starting the high temperature drying device 17 to a set temperature; heating the wire shaping device 18 and the wire shaping device 19 to a set temperature; starting the cooling device 21; starting the primary airflow widening fan 6 in the primary airflow widening device and the secondary airflow widening fan 11 in the secondary airflow widening device; and starting the winding device 24; (3) The carbon fibers are blown and expanded by the primary airflow expansion fan 6 in the primary airflow expansion device and the secondary airflow expansion fan 11 in the secondary airflow expansion device; The carbon fiber tow 3 drawn out from the carbon fiber raw yarn roll 1 enters the primary airflow widening device with a certain tension through the first tensioning wheel 2, passes through the primary airflow widening front anti-deviation mechanism 4, bypasses two primary airflow widening guide rollers 5, and is output after passing through the primary airflow widening rear anti-deviation mechanism 7. The primary airflow widening fan 6 is aimed at the carbon fiber tow 3 between the two primary airflow widening guide rollers 5 to blow the carbon fiber tow 3.

[0036] The carbon fiber tow 3 enters the secondary airflow widening device through the second tensioning wheel 8, passes through the secondary airflow widening front anti-deviation mechanism 9, bypasses two secondary airflow widening guide rollers 10, passes through the secondary airflow widening rear anti-deviation mechanism 12 and is output, and the secondary airflow widening fan 11 blows the carbon fiber tow 3.

[0037] The gas blown by the primary airflow widening fan 6 and the secondary airflow widening fan 11 is a hot airflow, and the carbon fiber tow 3 can reach a scattered state after being blown and expanded twice by the fans.

[0038] (4) The carbon fibers after being blown by the air flow enter the resin powder suspension 14 so that the resin powder fully adheres to the surface of each carbon fiber under the action of the liquid adsorption force; The carbon fiber tow 3 after being blown by the air flow bypasses the first guide wheel 13, enters the resin powder suspension 14 in the resin powder impregnation device, and is output after bypassing three impregnation and traction rollers 15.

[0039] The resin powder suspension 14 is prepared from PEEK powder, dispersant, and deionized water in a mass fraction ratio of 20:1:100. By adjusting the position and distance between the impregnation and traction rollers 15 in the impregnation device, the time of the carbon fiber tow 3 in the resin powder suspension can be controlled to ensure that the blown carbon fiber tow 3 is fully impregnated with the resin powder suspension 14. After impregnation, the ratio of carbon fiber to PEEK resin powder is such that the volume fraction of carbon fiber does not exceed 40%, that is, the resin content at this time is slightly higher than the resin content after making the prepreg filament.

[0040] (5) The impregnated carbon fiber and powder resin enter the high-temperature drying device 17, evaporating the liquid moisture on the resin powder and carbon fiber, and melting the resin powder at high temperature to further adhere to the surface of the carbon fiber; The impregnated carbon fiber and powder resin bypass the second guide wheel 16 and enter the high-temperature drying device 17. The temperature of the high-temperature drying device 17 cannot be lower than the melting temperature of the resin powder and cannot be higher than the decomposition temperature of the resin powder. The length of the high-temperature drying channel in the high-temperature drying device 17 ensures that the moisture on the impregnated carbon fiber tow can be dried at the set temperature and the resin powder can be melted, and the melted resin powder further adheres to the carbon fiber.

[0041] (6) The resin in a molten state together with the carbon fiber enters the wire shaping device 18 and takes on a preliminary prepreg filament shape under the drive of a pair of heat-resistant profiling rollers 181; (7) The preliminarily formed prepreg filament enters a pair of profiling rollers 191 in the wire trimming device 19 to further process the shape of the prepreg filament into an approximately cylindrical prepreg filament; (8) The obtained prepreg filament enters the cooling device 21 for cooling to prevent deformation of the wire caused by contact during the subsequent wire winding stage; The prepreg filament obtained by the wire trimming device 19 enters the cooling device 21 for cooling. The cooling device 21 reduces the temperature of the prepreg filament by releasing cold air flow to prevent deformation of the wire caused by contact during the subsequent wire winding stage.

[0042] (9) The cooled prepreg filament is drawn by the traction pair of rollers 23 and enters the winding device 24 for winding.

[0043] Although the above process describes the specific implementation manner of the present invention in conjunction with the accompanying drawings, it is not intended to limit the present invention. Any modifications and partial adjustments made by those skilled in the relevant art on the basis of the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A device for forming continuous carbon fiber composite material prepreg for 3D printing, characterized in that: The carbon fiber tow passes through the fiber unwinding device, air flow widening device, resin powder impregnation device, high temperature drying device, wire shaping device, wire shaping device, cooling device, and winding device in sequence; The airflow widening device has two airflow widening guide rollers, the carbon fiber tow passes around the two airflow widening guide rollers, and the airflow widening fan is aimed at the carbon fiber tow between the two airflow widening guide rollers; The resin powder impregnation device has a resin powder suspension; The wire shaping device is composed of a pair of rotating profiling rollers, each of which has a groove on its outer circumference, and the pair of grooves form a gap through which the carbon fiber tow passes; The wire shaping device is composed of a pair of rotating profiling rollers, each of which has a groove on its outer circumference, and the pair of grooves form a gap through which the carbon fiber tow passes; The directions of a pair of profiling rollers in the trimming device and a pair of profiling rollers in the shaping device are perpendicular to each other.

2. The device for forming continuous carbon fiber composite material prepreg for 3D printing according to claim 1, characterized in that: The airflow widening device has two airflow widening anti-deflection mechanisms, the airflow widening guide roller is located between the two airflow widening anti-deflection mechanisms, the airflow widening anti-deflection mechanism has an anti-deflection slot in the form of a through slot, and the carbon fiber bundle passes through the anti-deflection slot.

3. The device for forming continuous carbon fiber composite material prepreg for 3D printing according to claim 1, characterized in that: There are two airflow widening devices, namely a primary airflow widening device and a secondary airflow widening device, and the primary airflow widening device and the secondary airflow widening device have the same structure.

4. The device for forming continuous carbon fiber composite material prepreg for 3D printing according to claim 1, characterized in that: A tensioning wheel or a guide wheel is arranged between the fiber unwinding device, the air flow widening device, the resin powder impregnation device, the high temperature drying device, the wire shaping device, the wire shaping device, the cooling device and the winding device.

5. The device for forming continuous carbon fiber composite material prepreg for 3D printing according to claim 1, characterized in that: There are three impregnation traction rollers in the resin powder impregnation device, and the carbon fiber tow passes around the three impregnation traction rollers.

6. The device for forming continuous carbon fiber composite material prepreg for 3D printing according to claim 1, characterized in that: The contour rollers of the wire shaping device and the wire shaping device are both in a heated state.

7. The device for forming continuous carbon fiber composite material prepreg for 3D printing according to claim 1, characterized in that: The cross section of the grooves on the profiling rollers of the wire shaping device and the wire shaping device is semicircular, and a pair of grooves form a circular gap.

8. A method for forming a continuous carbon fiber composite material prepreg for 3D printing, comprising the following steps: (1) passing the carbon fiber tow through a fiber unwinding device, an air flow widening device, a resin powder impregnation device, a high temperature drying device, a wire shaping device, a wire shaping device, a cooling device, and a winding device in sequence; (2) adding the resin powder suspension into the resin powder impregnation device; starting the high temperature drying device to a set temperature; heating the wire shaping device and the shaping device to a set temperature; starting the cooling device; starting the airflow widening fan in the airflow widening device; and starting the winding device; (3) The carbon fiber is blown and expanded by the airflow expansion fan in the airflow expansion device; (4) The carbon fibers after being blown by the air flow enter the resin powder suspension so that the resin powder fully adheres to the surface of each carbon fiber under the action of the liquid adsorption force; (5) After impregnation, the carbon fiber and powdered resin enter a high-temperature drying device to evaporate the liquid moisture on the resin powder and carbon fiber, and melt the resin powder at high temperature to further adhere to the surface of the carbon fiber; (6) The molten resin and the carbon fiber enter the wire shaping device and are driven by a pair of heated profiling rollers to take on a preliminary prepreg shape; (7) The prepreg wire that is initially formed enters a pair of profiling rollers in the wire shaping device to further shape the prepreg wire into a prepreg wire that is approximately cylindrical; (8) The obtained prepreg enters the cooling device for cooling to prevent the wire from deforming due to contact in the subsequent wire collection stage; (9) After the prepreg is cooled, it is pulled into the winding device by the traction roller for winding.

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