A method and apparatus for 3D printing of thermoset polymer composites

Abstract

The application provides a thermosetting polymer composite 3D printing method and device, and the structure of the device comprises a rack, a control panel, an extruder, a stepping motor 1, a stepping motor 2, a stepping motor 3, a feeding system, a conduit, a molten pool, a stirrer, a nozzle device, a work platform, a hot bed and a hot air gun. The control panel of the device is connected with the extruder, the stepping motor 1, the stepping motor 2 and the stepping motor 3, the extruder controls the rotating speed of a rotating shaft, reciprocating movement of a plunger is driven, and the thermosetting polymer composite is extruded through a pinhole nozzle. The temperature and air speed of the hot bed and the hot air gun are adjusted, the thermosetting polymer composite is solidified and formed along the thickness direction, and the thermosetting polymer composite printing of a hollow structure such as a support-free structure can be realized. The designed 3D printing device can prepare the thermosetting polymer composite, which comprises but is not limited to functional properties such as electrical conductivity, thermal conductivity and electromagnetic shielding, can improve the multifunctionality of the thermosetting polymer composite, and can also meet certain mechanical properties.

Description

Technical Field

[0001] This invention relates to a method and apparatus for 3D printing thermosetting polymer composite materials. Specifically, it relates to 3D printing technology and methods; preparation of functional thermosetting polymer composite materials; structural design of 3D printing apparatus; and applications of thermosetting polymer composite materials. Background Technology

[0002] This invention, based on 3D printing technology, proposes a method and apparatus for 3D printing thermosetting polymer composite materials. Specifically, it relates to the structural design of the thermosetting polymer composite material 3D printing apparatus, the preparation of multifunctional thermosetting polymer composite materials, the application of 3D printing technology, and the application of thermosetting polymer composite materials, among other related technologies.

[0003] Traditional 3D printers are mostly thermoplastic, and the printing consumables include, but are not limited to, PLA, ABS, TPU, etc. This invention proposes to use thermosetting polymer materials as printing consumables, based on printing fillers including, but not limited to, BN, CF, EG, etc.

[0004] Traditional 3D printed products have the disadvantage of limited functional properties. This invention can directly prepare thermosetting polymer composite materials with multiple functions, or it can first prepare a thermosetting polymer matrix and then fill it with composite fillers with functional properties including but not limited to electrical conductivity, thermal conductivity, and electromagnetic shielding to prepare products with multiple performance requirements.

[0005] Thermosetting polymer matrices, including but not limited to phenolic resin matrices, epoxy resin matrices, and bismaleimide matrices, are used as composite material matrices. A thermosetting polymer composite material 3D printing device is designed, with the preparation principle being direct ink writing (DIW). Furthermore, due to the thermosetting properties of thermosetting polymer composite materials, thermosetting 3D printing without support structures can be achieved. Summary of the Invention

[0006] This invention proposes a 3D printing method and apparatus for thermosetting polymer composite materials. The designed 3D printing apparatus can achieve thorough mixing of thermosetting polymer materials and fillers, and the heated bed and hot air gun can regulate the temperature to ensure the thermosetting polymer composite material solidifies and forms the desired shape. Combining the 3D printing apparatus with thermosetting polymer composite materials allows for the preparation of thermosetting polymer composite materials with applications including, but not limited to, thermal management materials, electromagnetic shielding materials, and sensor materials. In terms of structure, it can meet the printing requirements of different material structures, achieving the printing of unsupported and other hollow structures.

[0007] This invention proposes a 3D printing method and apparatus for thermosetting polymer composite materials. The core technical points are: applying thermosetting polymer composite materials to a 3D printing apparatus; the extruder controls the reciprocating motion of the plunger to realize the intake and extrusion of thermosetting polymer composite materials; the thermosetting material and filler are mixed by stirring; and the thermosetting material and filler are mixed in a microchannel.

[0008] This invention proposes a method and apparatus for 3D printing thermosetting polymer composite materials. This printing method enables unsupported 3D printing of materials such as hollow structures, and is a novel technology for in-situ 3D printing of thermosetting polymer composite materials without any post-processing. After the composite ink is extruded from the printing nozzle and deposited, the ink undergoes front-side polymerization and curing, thereby rapidly printing high-quality composite materials. Customized processing conditions allow for freeform shaping and support the printing of 3D composite objects with zero porosity and high orientation.

[0009] This invention proposes a method and apparatus for 3D printing thermosetting polymer composite materials. The apparatus includes a frame. The frame structure of the 3D printing apparatus includes, but is not limited to, Cartesian, deltaic, and gantry frame types.

[0010] This invention proposes a method and apparatus for 3D printing thermosetting polymer composite materials. The apparatus includes a control board. The control board is connected to an extruder, stepper motor 1, stepper motor 2, and stepper motor 3 to realize the reciprocating motion of the plunger and the reciprocating motion of stepper motor 1, stepper motor 2, and stepper motor 3 in the X, Y, and Z directions, respectively.

[0011] This invention proposes a method and apparatus for 3D printing thermosetting polymer composite materials. The apparatus includes an extruder. A control panel controls the extruder's rotation speed to adjust the flow rate of the thermosetting polymer composite material at the nozzle.

[0012] This invention proposes a method and apparatus for 3D printing thermosetting polymer composite materials. The apparatus includes a stepper motor 1. The motor is located on the top of the frame and connected to a control board, and is used to control the reciprocating movement of the nozzle device along the X direction.

[0013] This invention proposes a method and apparatus for 3D printing thermosetting polymer composite materials. The apparatus includes a stepper motor 2. The motor is located at the bottom of the frame, and its shaft is connected to a belt. Through belt drive, the work platform reciprocates along the Y direction.

[0014] This invention proposes a method and apparatus for 3D printing thermosetting polymer composite materials. The apparatus includes a stepper motor 3. This motor and a stepper motor 2 are located at the same level, and the stepper motor 1 and the nozzle device reciprocate together along the Z direction by rotating the shaft.

[0015] This invention proposes a method and apparatus for 3D printing thermosetting polymer composite materials. The apparatus includes a feeding system. The thermosetting matrix and filler are respectively placed in the feeding system, and the thermosetting material and filler are forced into the molten pool and mixed by a negative pressure air pump.

[0016] This invention proposes a method and apparatus for 3D printing thermosetting polymer composite materials. The apparatus includes a conduit. The conduit connects the molten pool and the feeding system to ensure that the thermosetting material and filler are extruded into the molten pool and mixed.

[0017] This invention proposes a method and apparatus for 3D printing thermosetting polymer composite materials. The apparatus includes a molten pool. A stirrer is installed inside the molten pool to mix the thermosetting material and filler into a mixture.

[0018] This invention proposes a 3D printing method and apparatus for thermosetting polymer composite materials. The apparatus includes a nozzle device. The nozzle device consists of three parts: a plunger, a microchannel, and a pinhole nozzle, and is connected to the molten pool. The plunger enables the intake and extrusion of the thermosetting polymer composite material in the molten pool. The printing apparatus can perform printing including, but not limited to, single-nozzle printing, dual-nozzle printing, and multi-nozzle printing, and the number of nozzles can be selected according to the material composition. The microchannel types include, but are not limited to, micrometer-scale, millimeter-scale, and micro-mixer structures, and the microchannels can be selected according to the type of filler in the composite material.

[0019] This invention proposes a method and apparatus for 3D printing thermosetting polymer composite materials. The apparatus includes a working platform. A heated bed and a hot air gun fixed on the working platform can ensure the curing and molding of the thermosetting polymer composite material by adjusting the temperature and airflow.

[0020] This invention proposes a method and apparatus for 3D printing thermosetting polymer composite materials. The printing method includes the following specific steps:

[0021] Step 1: Operation of the feeding system of this device

[0022] The conduit connects the feeding system to the molten pool. The air pump in the feeding system uses negative pressure to force the thermosetting material and filler into the conduit, and then into the molten pool for thorough mixing.

[0023] Step Two: The Work of the Mixer

[0024] The agitator in the molten pool thoroughly mixes the thermosetting material with the filler.

[0025] Step 3: Modeling of Thermosetting Polymer Composites

[0026] Three-dimensional modeling software is used to design the model structure of thermosetting polymer composite materials to ensure that they have certain mechanical properties.

[0027] Thermosetting polymer composite material structures designed using 3D modeling include, but are not limited to, 3D porous structures, spatial truss structures, and spatial hexagonal structures.

[0028] Step 4: The extruder achieves the reciprocating motion of the plunger by rotating the shaft.

[0029] The extruder is connected to the control panel, and the extrusion speed of the thermosetting polymer composite material at the needle nozzle is controlled by controlling the rotation speed of the extruder shaft.

[0030] Step 5: Stepper motor 1, stepper motor 2, and stepper motor 3 of the device reciprocate along the X, Y, and Z directions respectively.

[0031] The control board is connected to stepper motor 1, stepper motor 2, and stepper motor 3, and each stepper motor can work normally.

[0032] Step Six: Extrusion of Thermosetting Polymer Composites

[0033] Under the action of the plunger, the thermosetting polymer composite material in the molten pool is squeezed into the microchannel for secondary mixing, and then extruded at the pinhole nozzle.

[0034] Step 7: Thermosetting polymer composite material is cured and molded on the working platform.

[0035] The use of heated beds and hot air guns to regulate temperature ensures the curing and molding of thermosetting polymer composites.

[0036] By adjusting the temperature and air speed of the heated bed and hot air gun, it is possible to mold thermosetting polymer composites with different thickness directions and prepare thermosetting polymer composites with different unsupported structures.

[0037] Phenolic resin, as a thermosetting material, is soluble in strong acids but corrodes in strong alkalis. Chemically, it is insoluble in water but soluble in organic solvents such as acetone. Due to its excellent corrosion resistance, high-temperature resistance, and good structural properties, phenolic resin cured materials prepared using thermosetting 3D printing equipment can be used in fireproofing applications.

[0038] Epoxy resin, a common thermosetting material in daily life, is often used as a sizing agent to provide support and protection in some two-phase materials. By plating copper on the surface of carbon fiber felt to form good thermal and electrical conductivity pathways, and finally filling it with epoxy resin as a scaffold, the thermal and electrical conductivity of the composite material can be greatly improved.

[0039] Carbon fiber, as an excellent conductive filler, is often used as a functional filler in composite materials to achieve the preparation of functional composite materials. Leveraging the advantage of thermosetting 3D printing in fabricating unsupported structures, carbon fiber-based composite materials with hollow structures can be printed and applied to flexible sensors, among other applications. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the structure of a thermosetting polymer composite material 3D printing device according to the present invention;

[0041] Figure 2 This is a schematic diagram of the nozzle device of the present invention;

[0042] Figure 3 This is a schematic diagram of the feeding system of the present invention;

[0043] The above-described embodiments are merely preferred implementation examples and provide new research ideas for the design of 3D printing methods and devices for thermosetting polymer composite materials, but they cannot be used to limit the scope of the patent. In the figures: 1. Frame, 2. Extruder, 3. Conduit, 4. Feeding system, 5. Hot air gun, 6. Stepper motor 3, 7. Control board, 8. Belt, 9. Stepper motor 2, 10. Guide rod, 11. Working platform, 12. Nozzle device, 13. Stepper motor 1, 14. Stirrer, 15. Pin nozzle, 16. Microchannel, 17. Plunger, 18. Molten pool, 19. Air pump, 20. Thermosetting material, 21. Filler. Detailed Implementation

[0044] A method and apparatus for 3D printing thermosetting polymer composite materials are disclosed. The printed thermosetting polymer composite materials are mainly used for applications including but not limited to electrical conductivity, thermal conductivity, electromagnetic shielding, vibration damping and noise reduction, as well as for printing thermosetting polymer composite materials with unsupported or hollow structures. This invention is merely a further explanation of the applications of the printed products; this explanation is illustrative but not intended to limit the application and scope of the invention.

[0045] Example 1: Preparation of short carbon fiber reinforced thermosetting polymer composites

[0046] Example 1 includes the following steps:

[0047] Step 1: The materials selected are: dicyclopentadiene (DCPD), 5-ethylidene-2-demethylborene (ENB), and second-generation Grubbs' catalyst (GC2), cyclohexylbenzene (Acros Organics, 98%), and short carbon fibers.

[0048] DCPD was melted in an oven at 60 °C, and 5 wt% ENB was added to suppress its melting point. For all samples, GC2 and TBP were added to cyclohexylbenzene, and the solution was then mixed with DCPD and short carbon fibers. Pre-curing was performed in an oven at 30 °C for 1 h to enhance rheological properties, and finally, the printing ink was transferred to a thermosetting 3D printer.

[0049] Step Two: Preparation of Short Carbon Fiber / Dicyclopentadiene Thermosetting Polymer Composites

[0050] The heating temperature of the heated bed allows for in-situ polymerization and rapid curing of the printed polymer composite material at its front end, enabling unsupported free printing of composite material structures.

[0051] Example 2: Preparation of boron nitride@styrene / epoxy (BN@SA / Epoxy) thermally conductive composite material.

[0052] Example 2 includes the following specific steps:

[0053] Step 1: Preparation of a Printing Substrate Capable of Supporting Thermally Conductive Fillers

[0054] The Solidworks 3D software was used to create a model, and Cura slicing was used to import the sliced ​​model into a thermosetting polymer composite material 3D printing device. The nozzle device moved along the specified path, and the extruded composite material was stacked on the work platform to form a concentric ring shape that could be filled with thermally conductive composite material.

[0055] Step 2: Preparation of the thermally conductive composite material boron nitride@styrene (BN@SA)

[0056] BN with a particle size of 10-15 μm and SA with a thermal conductivity of 0.24 / (m⋅K) were mixed at a mass ratio of 3:2 and mechanically stirred for 3 h to form a homogeneous composite with a mass fraction of 60% BN.

[0057] Step 3: Preparation of Boron Nitride@Styrene / Epoxy (BN@SA / Epoxy)

[0058] The printed thermally conductive substrate is placed on the worktable, and the prepared boron nitride@styrene (BN@SA) is filled into the epoxy resin of the printed substrate, thus initially obtaining the boron nitride@styrene / epoxy resin (BN@SA / Epoxy) composite.

[0059] Step 4: Post-treatment of boron nitride@styrene / epoxy resin (BN@SA / Epoxy)

[0060] The initially prepared boron nitride@styrene / epoxy resin (BN@SA / Epoxy) was subjected to hot pressing and cured in a vacuum chamber at 80°C for 12 hours to obtain a stable boron nitride@styrene / epoxy resin (BN@SA / Epoxy) with thermal conductivity.

[0061] Example 3: Preparation of porous thermosetting polyimide (TSPI) oil-containing composites with high wear resistance and heat resistance

[0062] Example 3 includes the following specific steps:

[0063] Step 1: Preparation of phenylacetylene-terminated polyamic acid (PAA) powder

[0064] 4,4'-(hexafluoroisopropene)phthalic anhydride (6FDA) with a purity of 99%, diaminodiphenyl ether (ODA), and 4-phenylethynyl phthalic anhydride (PEPA) with a purity of 98% were selected as raw materials. Diaminodiphenyl ether (ODA) and N-methylpyrrolidone (NMP) were separately placed in a three-necked flask with a nitrogen delivery tube and mechanically stirred. The resulting mixture was stirred in an ice bath for 20 minutes. 4,4'-(hexafluoroisopropene)phthalic anhydride (6FDA) was added to the remaining N-methylpyrrolidone (NMP) solution in three portions. After reacting in an ice bath for 1 hour, the reaction was continued at room temperature for 5 hours. Subsequently, 4-phenylethynyl phthalic anhydride (PEPA) was added, and the mixture was reacted for 24 hours to obtain a polyamic acid (PAA) solution. The prepared polyamic acid (PAA) solution was coated onto a clean glass plate and then dried in an oven at 70°C for 12 hours to obtain polyamic acid (PAA) with a small amount of residual N-methylpyrrolidone (NMP). After pulverization, polyamic acid (PAA) powder was obtained.

[0065] Step 2: Preparation of polyamic acid / carbon fiber (PAA / CF) composite ink

[0066] The polyamic acid (PAA) powder prepared in step one, N,N-dimethylformamide (DMF), and carbon fiber (CF) were mixed in a certain proportion. The mixture was ball-milled at a speed of 2500-3000 r / min for 5 min until the white NaCl in the mixture disappeared. Finally, the mixture was placed in a 10 ml syringe at a speed of 6000-8000 r / min for 5 min to prepare the polyamic acid / carbon fiber (PAA / CF) composite ink.

[0067] Step 3: Preparation of porous polyimide / carbon fiber (TSPI / CF) oil-containing composite material

[0068] In the thermosetting polymer composite 3D printing equipment, the printing path, nozzle diameter, nozzle-to-platform distance, and working speed are pre-set. The printed porous composite material is washed in 70°C distilled water to remove NaCl, and the distilled water is changed every 4 hours until 24 hours. After the material is dried, it is vacuum impregnated with oil at 60°C to obtain the porous polyimide / carbon fiber (TSPI / CF) oil-impregnated composite material.

[0069] Example 4: Preparation of boron nitride / polydimethylsiloxane (BN / PDMS) composite material with directional thermally conductive structure

[0070] Example 4 includes the following specific steps:

[0071] Step 1: Blending of boron nitride / polydimethylsiloxane (BN / PDMS)

[0072] Add 10wt%, 20wt%, and 30wt% of boron nitride (BN) thermally conductive filler to polydimethylsiloxane (PDMS), respectively, and place them in a homogenizer without adding a curing agent, and disperse them at 1500 r / min for 1 min.

[0073] Step 2: Preparation of boron nitride / polydimethylsiloxane (BN / PDMS) thermosetting polymer composite material

[0074] Polydimethylsiloxane (PDMS) and curing agent were blended at a mass ratio of 10:1, and the homogenizer was rotated at 500 r / min. Then, degassing treatment was performed.

[0075] Step 3: Printing and fabricating a boron nitride / polydimethylsiloxane (BN / PDMS) thermally conductive composite material with a special structure.

[0076] The plunger ensures that the boron nitride / polydimethylsiloxane (BN / PDMS) composite material is extruded at the pin nozzle, which moves along a designated path. The heated bed temperature is set to 100°C, and the boron nitride / polydimethylsiloxane (BN / PDMS) is cured and formed on the working platform.

[0077] Example 5: Printing of High-Strength, Low-Energy Continuous Carbon Fiber / Epoxy (CF / Epoxy) Thermosetting Composites Based on Dual-Nozzle Printers

[0078] Example 5 includes the following specific steps:

[0079] Step 1: Preparation of Curable Epoxy Resin

[0080] Bis[4-(tert-butyl)phenyl]iodonium tetra(nonafluorotert-butoxy)aluminate (I-Al) and a thermal initiator (I-TI) were mixed with epoxy resin. I-Al / I-TI initiator concentrations ranging from 0.02 mol% to 1 mol% / 2 mol% to 8 mol% were added to the epoxy resin. The mixture of I-Al, I-TI, epoxy resin, and dichloromethane was subjected to bath sonication to ensure complete mixing. The mixture was then rotary evaporated prior to printing to remove the solvent.

[0081] Step 2: Continuous Carbon Fiber (CF) Printing

[0082] Continuous carbon fiber composites are printed using a dual-nozzle process, in which continuous carbon fiber (CF) tows are immersed in a container of reactive epoxy resin. The print bed temperature is set to 120°C, ensuring the continuity of the printed CF tows and forming an in-situ cured structure defined by the computer model. To prevent clogging, the offset distance between the nozzle and the platform is set to 1 mm.

Claims

1. A thermoset polymer composite 3D printing device, characterized in that, The device comprises a rack, a control board, an extruder, a stepper motor one, a stepper motor two, a stepper motor three, a feeding system, a conduit, a stirrer, a nozzle device, a work platform, a hot air gun; The feeding system is connected with the extruder through the conduit, and the extruder is installed on the rack through a support; the position of the extruder on the rack is adjusted through the stepper motor one; the nozzle device at the bottom of the extruder is vertically aligned with the work platform; the bottom of the work platform is provided with a guide rod; the stepper motor two drives the guide rod to drive the work platform to move horizontally and longitudinally through a belt; the stepper motor two, the work platform and the guide rod are all installed on a bottom frame, and the stepper motor three drives the bottom frame to move horizontally and transversely; the hot air gun is installed on one side of the work platform and is used for heating the thermosetting polymer composite material sprayed by the nozzle device; the hot air gun, the stepper motor one, the stepper motor two and the stepper motor three are all connected with the control board; The feeding system comprises a gas pump, a thermosetting material and a filler; The nozzle device comprises a molten pool, a stirrer, a plunger, a micro flow channel and a needle hole nozzle; The thermosetting material and the filler are driven by the gas pump to the molten pool of the nozzle device through the conduit, and the molten pool is provided with the stirrer; the lower part of the molten pool is provided with the plunger, and the thermosetting material and the filler stirred by the stirrer are sprayed to the work platform through the micro flow channel and the needle hole nozzle; The thermosetting material and the filler are respectively added to the feeding system, and the thermosetting material and the filler are extruded into the molten pool for mixing through the negative pressure of the gas pump; The control board is connected with the stepper motor one, the stepper motor two and the stepper motor three to realize the reciprocating motion in the X, Y and Z directions; The control board is connected with the extruder, and the rotation shaft of the extruder controls the plunger in the nozzle device to realize the suction and extrusion of the thermosetting polymer composite material in the molten pool; The control board realizes the curing and forming of different thermosetting polymer composite materials by adjusting the temperature of the hot bed on the work platform and the hot air gun.

2. The thermoset polymer composite 3D printing device of claim 1, wherein: The molten pool is connected with the feeding system through the conduit, and the stirrer is installed inside the molten pool.

3. The thermoset polymer composite 3D printing device of claim 1, wherein: The nozzle device is composed of the plunger, the micro flow channel and the needle hole nozzle and is connected with the molten pool, and the printing device realizes the single nozzle printing, the double nozzle printing and the multi-nozzle printing, and the number of the nozzle device is selected according to the material components.

4. The thermoset polymer composite 3D printing device of claim 1, wherein The types of the micro flow channel include the micron level, the millimeter level and the micro mixer structure, and the micro flow channel is selected according to the types of the fillers in the composite material.

5. The thermoset polymer composite 3D printing device of claim 1, wherein: The diameter of the needle hole nozzle includes 0.4 mm, 0.8 mm and 1.2 mm, and the diameter of the needle hole nozzle is changed according to the viscosity of the composite material.

6. A method for 3D printing of a thermoset polymer composite material according to any one of claims 1 to 5, characterized in that, The printing method comprises the following steps: Step one: the feeding system runs: the feeding system is connected with the molten pool through the conduit, and the gas pump in the feeding system can extrude the thermosetting material and the filler into the conduit through the negative pressure, and then into the molten pool for sufficient mixing; Step two: the stirrer works: the stirrer in the molten pool stirs the thermosetting material and the filler sufficiently; Step three: the model of the thermosetting polymer composite material is established: a three-dimensional modeling software is applied to design the model structure of the thermosetting polymer composite material to ensure that it has certain mechanical properties; Step four: the extruder rotates through the shaft to realize the reciprocating motion of the plunger: the extruder is connected with the control panel, and the extrusion speed of the thermosetting polymer composite at the needle hole nozzle is realized by controlling the rotating speed of the shaft of the extruder; Step five: stepper motor one, stepper motor two and stepper motor three reciprocate along the X, Y and Z directions respectively: the stepper motor one, the stepper motor two and the stepper motor three are connected with the control panel, and each stepper motor can work normally; Step six: extrusion of thermosetting polymer composite: under the action of the plunger, the thermosetting polymer composite in the melt pool is extruded into the micro channel for secondary mixing, and then extruded at the needle hole nozzle; Step seven: 3D printing thermosetting polymer composite is solidified and formed on the working platform: the temperature of the hot bed and the hot air gun is adjusted according to the solidification requirement of the thermosetting polymer composite.

7. The method according to claim 6, wherein the method is a method for 3D printing of a thermoset polymer composite. The rack structure of the 3D printing device includes Cartesian type, delta type and gantry type.

8. The method of claim 6, wherein the thermoset polymer composite 3D printing method is characterized by: The thermosetting polymer matrix used by the 3D printing device includes phenolic resin matrix, epoxy resin matrix and bismaleimide matrix as the composite matrix.

9. The method and apparatus for 3D printing of thermoset polymer composites according to claim 6, wherein, The functional properties of the prepared thermosetting polymer composite include heat conduction, electricity conduction and electromagnetic shielding, and the application range includes heat management materials, electromagnetic shielding materials and sensor materials.

Images