3D printing device and method for a heterogeneous continuous fiber reinforced composite material

Abstract

The present invention provides a 3D printing device and method for a heterogeneous continuous fiber-reinforced composite material. The 3D printing device includes a frame, a moving mechanism, a printing head assembly, a wire feeding assembly, and a control device. A printing platform is provided on the frame. The moving mechanism is installed on the frame. The printing head assembly includes a processing head and a heating block. The processing head is connected to the moving mechanism. The processing head is provided with a first wire outlet hole and at least one side hole for the wire to enter. The wires entering through the multiple side holes all pass through the first wire outlet hole. The heating block is connected to the processing head. The wire feeding assembly includes a wire feeding disc, a wire feeding support, a wire feeding motor, and a guiding tube. The wire feeding disc is rotatably installed on the frame. The wire feeding support is connected to the moving mechanism. The wire feeding motor is installed on the wire feeding support. The guiding tube is installed on the wire feeding support. By means of this device, synchronous melting and compaction of the wire can be achieved, avoiding the phenomena of blocking the processing head and wire breakage, and making the additive manufacturing process more continuous and reliable.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing, and in particular, to a 3D printing device and process for heterogeneous continuous fiber reinforced composite materials. Background Art

[0002] Fiber reinforced polymer composite materials have many advantages such as high specific strength, high specific stiffness, and strong designability, and are widely used in the fields of aerospace, transportation equipment, energy equipment, sports equipment, etc. 3D printing is an emerging technology for constructing three-dimensional objects through layer-by-layer slicing and layer-by-layer deposition of materials. 3D printing technology has a wide range of applications in the fields of aerospace, rail transit, electronics, and biomedicine. Through 3D printing technology, various heterogeneous continuous fibers can be synchronously printed to manufacture components, which can significantly improve the durability of composite materials and the mechanical properties of components. In the 3D printing process, the fused filament fabrication (FFF) process has the characteristics of moldless forming, strong designability, rapid prototyping, and low cost, further expanding the application scope of continuous fiber reinforced composite materials.

[0003] Currently, the mainstream FFF technology forms by feeding the wire into a closed print head, heating and melting it inside, and then extruding it. In this forming method, the wire is heated and melted inside the print head, and the temperature decreases when it is extruded to the outlet, and the extruded material is partially solidified, which easily causes blockage of the extrusion port, resulting in a decrease in forming accuracy or even inability to form; only one wire of a single specification can be fed, and the wire feeding position is not stable enough, affecting the manufacturing accuracy and the forming process. Summary of the Invention

[0004] In view of this, the present invention proposes a 3D printing device and method for heterogeneous continuous fiber reinforced composite materials to solve the technical problems mentioned in the above background art, that is, the wire is heated and melted inside the print head, the temperature decreases when it is extruded to the outlet, the extruded material is partially solidified, which easily causes blockage of the extrusion port, resulting in a decrease in forming accuracy or even inability to form.

[0005] The technical solution of the present invention is realized as follows:

[0006] In a first aspect, the present invention provides a 3D printing device for heterogeneous continuous fiber reinforced composite materials, including a frame, a moving mechanism, a print head assembly, a wire feeding assembly, and a control device, wherein:

[0007] A print platform is provided on the frame, and the print platform is equipped with a preheating device;

[0008] The moving mechanism is installed on the frame;

[0009] The printing head assembly includes a processing head and a heating block. The processing head is connected to the moving mechanism. The processing head is provided with a first wire outlet hole and at least one side hole for the wire to enter. The first wire outlet hole is located at the bottom surface of the processing head, and the wires entering through the multiple side holes all pass through the first wire outlet hole. The heating block is connected to the processing head and is used to heat the processing head and the wire during the process that the processing head presses the wire passing through the first wire outlet hole onto the printing platform or the deposited layer.

[0010] The wire feeding assembly includes a wire feeding disk, a wire feeding support, a wire feeding motor, and a guiding tube. The wire feeding disk is rotatably installed on the frame. The wire feeding support is connected to the moving mechanism. The wire feeding motor is installed on the wire feeding support and is used to drive the wire on the wire feeding disk to move into the guiding tube. The guiding tube is installed on the wire feeding support and is used to sequentially guide the wire into the side hole and the first wire outlet hole.

[0011] The control device is electrically connected to the moving mechanism, the heating block, and the wire feeding motor in terms of electrical signals.

[0012] Based on the above technical solutions, preferably, the moving mechanism includes a connecting plate, a moving base, and a moving unit. The connecting plate is respectively connected to the processing head and the wire feeding support. The moving base is respectively connected to the moving unit and the connecting plate and is used to drive the connecting plate to perform multi-degree-of-freedom movement under the drive of the moving unit.

[0013] Based on the above technical solutions, preferably, the moving unit includes an X-axis, a Y-axis, a Z-axis, and three driving members. The X-axis and the Y-axis are slidably arranged on the frame. The Z-axis is respectively connected to the moving base and the connecting plate. The moving base is slidably installed on the X-axis and the Y-axis. The three driving members are installed on the moving base and are respectively used to drive the moving base to move along the X-axis and the Y-axis, and the connecting plate to move along the Z-axis.

[0014] Based on the above technical solutions, preferably, the moving unit adopts a robotic arm or a five-axis machine tool.

[0015] Based on the above technical solutions, preferably, there are multiple side holes, and the first wire outlet hole is communicated with the side holes. One end of the guiding tube is located at the wire outlet position of the wire feeding motor, and the other end faces the side holes, and the first wire outlet hole is located in the extending direction of the guiding tube.

[0016] Based on the above technical solutions, preferably, the wire feeding support is provided with a wire inlet hole and a second wire outlet hole. The wire on the wire feeding disk passes through the wire inlet hole and then passes through the second wire outlet hole and enters the guiding tube.

[0017] The wire feeding assembly further includes two wire feeding rollers rotatably mounted on the wire feeding bracket. The wire feeding motor is drivingly connected to one of the wire feeding rollers. The two wire feeding rollers clamp the wire and are used to pull the wire out from the wire feeding reel and move it into the guiding tube, so as to supply the wire to the first wire outlet hole.

[0018] Based on the above technical solutions, preferably, the printing head assembly further includes a mounting frame, the mounting frame is connected to the connecting plate, the mounting frame is provided with a hollow structure, and the heating block is mounted on the hollow structure and is thermally connected to the processing head.

[0019] Based on the above technical solutions, preferably, the printing head assembly further includes a pressure sensor mounted above the heating block. The pressure sensor is used to monitor the pressure value received by the processing head and feedback the pressure value to the control device, so as to control the processing head to maintain the pressing force between the wire and the printing platform or the deposited layer.

[0020] In a second aspect, the present invention provides a 3D printing method for a heterogeneous continuous fiber reinforced composite material, using the 3D printing device for a heterogeneous continuous fiber reinforced composite material as described in the first aspect, including:

[0021] Controlling, by the control device, the moving mechanism to drive the processing head so that the processing head moves above the printing platform and maintains a set layer height spacing from the printing platform or the deposited layer, and passes the front end of the wire through the side hole and the first wire outlet hole;

[0022] Controlling, by the control device, the wire feeding motor to drive the wire on the wire feeding reel to move into the guiding tube;

[0023] Controlling, by the control device, the moving device to drive the processing head to move along a given path, and controlling the processing head to maintain a constant pressing force on the wire passing through the first wire outlet hole;

[0024] Controlling, by the control device, the heating block to heat the processing head and the wire during the process that the processing head presses the wire passing through the first wire outlet hole onto the printing platform or the deposited layer, so as to realize the synchronous melting and compaction of the wire.

[0025] Based on the above technical solutions, preferably, the wire feeding speed at which the wire feeding motor drives the wire on the wire feeding reel to move into the guiding tube is 120 - 240 mm / min; the temperature at which the heating block heats the processing head and the wire is 175 - 205 °C; the thickness of each deposited layer is 0.12 - 0.22 mm.

[0026] The 3D printing device and method for a heterogeneous continuous fiber reinforced composite material of the present invention have the following beneficial effects compared with the prior art:

[0027] (1) Drive the wire on the wire feeding disc to move into the guiding tube by the wire feeding motor. The guiding tube sequentially guides the wire into the side holes and the first wire outlet hole, and the wires entering through multiple side holes all pass through the first wire outlet hole. During the process that the heating block presses the wire passing through the first wire outlet hole against the printing platform or the deposited layer on the processing head, heat the processing head and the wire to achieve synchronous melting and compaction of the wire. Compared with the prior art method of heating first and then extruding in the processing head, it avoids the phenomena of blockage of the processing head and wire breakage, making the additive manufacturing process more continuous and reliable.

[0028] (2) Connect the connecting plate to the processing head and the wire feeding support respectively, and connect the moving base to the moving unit and the connecting plate respectively. The moving base is used to drive the connecting plate to move with multiple degrees of freedom under the drive of the moving unit, so as to realize the movement of the processing head and the wire feeding support together with the connecting plate, and the processing head for wire outlet and the wire feeding support for wire supply move synchronously. Thus, the processing head can move along a preset processing path, improving the reliability of the device.

[0029] (3) By designing multiple side holes, wires of continuous fiber reinforced composite materials of different models can be respectively fed into the corresponding side holes of the processing head. Under the coordinated action of their respective wire feeding mechanisms, they can be synchronously fed into the first wire outlet hole of the processing head, and synchronous melting and compaction of wires of multiple specifications can be achieved. The operation is simple and the forming effect is good, achieving the purpose of synchronous coupling printing of multiple materials. One end of the guiding tube is located at the wire outlet position of the wire feeding motor, the other end faces the side hole, and the first wire outlet hole is located in the extending direction of the guiding tube, making the wire feeding position of the wire very stable, improving the manufacturing accuracy, and avoiding affecting the forming process.

[0030] (4) Clamp the wire by two wire feeding rollers. The wire feeding motor is drivingly connected to one of the wire feeding rollers. During the rotation of the wire feeding rollers, pull the wire to be released from the wire feeding disc and move it into the guiding tube to supply wire to the first wire outlet hole. When the wire feeding motor stops rotating, the wire supply can be immediately stopped, and the wire can be clamped and fixed. This wire supply method is simple and reliable, ensuring the continuous progress of processing and being convenient and fast to stop processing. Description of the Drawings

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0032] Figure 1Schematic structural diagram of the 3D printing device for heterogeneous continuous fiber reinforced composite materials in the embodiments of the present invention;

[0033] Figure 2 Schematic principle diagram of wire feeding of the 3D printing device for heterogeneous continuous fiber reinforced composite materials in the embodiments of the present invention;

[0034] Figure 3 Schematic structural diagram of the print head assembly in the embodiments of the present invention;

[0035] Figure 4 Schematic structural diagram of the wire feeding bracket and the guide tube in the embodiments of the present invention;

[0036] Figure 5 Schematic structural diagram of the print head in the embodiments of the present invention;

[0037] Figure 6 Schematic diagram of the printing principle of the 3D printing device for heterogeneous continuous fiber reinforced composite materials in the embodiments of the present invention;

[0038] Figure 7 Schematic flow chart of the 3D printing method for heterogeneous continuous fiber reinforced composite materials in the embodiments of the present invention;

[0039] Figure 8 Schematic diagram of the relationship between the flexural strength and the layer thickness, heating temperature and wire feeding speed of the deposited layer;

[0040] Figure 9 Schematic diagram of the relationship between the flexural modulus and the layer thickness, heating temperature and wire feeding speed of the deposited layer;

[0041] Figure 10 Photos of the formed product with a deposition thickness of 0.15 mm (a) and the formed product with a deposition thickness of 0.12 mm (b) in the embodiments of the present invention.

[0042] Explanation of reference numerals: 1 - frame, 2 - moving mechanism, 3 - print head assembly, 4 - wire feeding assembly;

[0043] 11 - printing platform;

[0044] 21 - moving base, 22 - connecting plate, 23 - moving unit, 231 - X-axis, 232 - Y-axis, 233 - Z-axis;

[0045] 31 - processing head, 311 - side hole, 312 - first wire outlet hole, 32 - heating block, 33 - mounting bracket;

[0046] 41 - wire feeding reel, 42 - wire feeding bracket, 421 - wire inlet hole, 422 - second wire outlet hole, 43 - guide tube, 44 - wire feeding roller. Specific Embodiments

[0047] The following will describe the technical solutions in the embodiments of the present invention clearly and completely in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0048] Referring to Figures 1-6 As shown, in the first aspect embodiment of the present invention, a 3D printing device for heterogeneous continuous fiber-reinforced composite materials is proposed, including a frame 1, a moving mechanism 2, a printing head assembly 3, a wire feeding assembly 4, and a control device, where:

[0049] A printing platform 11 is provided on the frame 1, and the printing platform 11 is equipped with a preheating device that can preheat the printing platform 11;

[0050] The moving mechanism 2 is installed on the frame 1 and is used to drive the printing head assembly 3 and the wire feeding assembly 4 to move;

[0051] The printing head assembly 3 includes a processing head 31 and a heating block 32. The processing head 31 is connected to the moving mechanism 2; the processing head 31 is provided with a first wire outlet hole 312 and at least one side hole 311 for the wire to enter. The first wire outlet hole 312 is located at the bottom surface of the processing head 31, and the wires entering through the plurality of side holes 311 all pass through the first wire outlet hole 312; the heating block 32 is connected to the processing head 31 and is used to heat the processing head 31 and the wire during the process of the processing head 31 pressing the wire passing through the first wire outlet hole 312 onto the printing platform 11 or the deposited layer;

[0052] The wire feeding assembly 4 includes a wire feeding disk 41, a wire feeding bracket 42, a wire feeding motor, and a guiding tube 43. The wire feeding disk 41 is rotatably installed on the top surface of the frame 1 and is used to store the unformed wire; the wire feeding bracket 42 is connected to the moving mechanism 2; the wire feeding motor is installed on the wire feeding bracket 42 and is used to drive the wire on the wire feeding disk 41 to move into the guiding tube 43; the guiding tube 43 is installed on the wire feeding bracket 42 and is used to sequentially guide the wire into the side hole 311 and the first wire outlet hole 312;

[0053] The control device is electrically connected to the moving mechanism 2, the heating block 32, and the wire feeding motor to control the operation of the moving mechanism 2, the heating block 32, and the wire feeding motor.

[0054] In this embodiment, after the 3D printing device is installed, the modeling, slicing, path planning, and export of the path code of the model are completed on the computer. During path planning, demand characteristics of different materials are set according to the characteristics of the formed part, and the path code is imported into the control device. According to the requirements of the formed part, the respective wire feeding assemblies 4 are automatically selected, the specific model of the prepreg wire is determined, and they are respectively fed into different side holes 311 in the processing head 31. The temperature of the preheating mechanism and the wire feeding speed are adjusted. The processing head 31 presses the wire passing through the first wire outlet hole 312 against the printing platform 11 or the deposited layer, and the heating block 32 synchronously heats the wire passing through the first wire outlet hole 312.

[0055] For the 3D printing device of the heterogeneous continuous fiber-reinforced composite material proposed in this embodiment, the wire feeding motor drives the wire on the wire feeding disk 41 to move into the guiding tube 43. The guiding tube 43 sequentially guides the wire into the side hole 311 and the first wire outlet hole 312. The wires entering through multiple side holes 311 all pass through the first wire outlet hole 312. During the process that the processing head 31 presses the wire passing through the first wire outlet hole 312 against the printing platform 11 or the deposited layer, the heating block 32 heats the processing head 31 and the wire, realizing the synchronous melting and compaction of the wire. Compared with the prior art method of heating first and then extruding in the processing head 31, the phenomena of blockage of the processing head 31 and wire breakage are avoided, making the additive manufacturing process more continuous and reliable.

[0056] In some embodiments, the moving mechanism 2 includes a connecting plate 22, a moving base 21, and a moving unit 23. The connecting plate 22 is respectively connected to the processing head 31 and the wire feeding support 42. The moving base 21 is respectively connected to the moving unit 23 and the connecting plate 22, and is used to drive the connecting plate 22 to perform multi-degree-of-freedom movement under the drive of the moving unit 23. By driving the connecting plate 22 to perform multi-degree-of-freedom movement under the drive of the moving unit 23 through the moving base 21, the processing head 31 and the wire feeding support 42 move together with the connecting plate 22, and the processing head 31 for wire outlet and the wire feeding support 42 for wire supply move synchronously. Thus, the processing head 31 can move along the preset processing path, improving the reliability of the device.

[0057] In some embodiments, the moving unit 23 includes an X-axis 231, a Y-axis 232, a Z-axis 233, and three driving members. The X-axis 231 and the Y-axis 232 are slidably disposed on the frame 1. The Z-axis 233 is respectively connected to the moving base 21 and the connecting plate 22. The moving base 21 is slidably mounted on the X-axis 231 and the Y-axis 232. The three driving members are mounted on the moving base 21 and are respectively used to drive the moving base 21 to move along the X-axis 231 and the Y-axis 232, and the connecting plate 22 to move along the Z-axis 233. By driving the moving base 21 to move along the X-axis 231 and the Y-axis 232, and the connecting plate 22 to move along the Z-axis 233 respectively by the three driving members, three-way movement of the connecting plate 22 along the X-axis 231, the Y-axis 232, and the Z-axis 233 is realized, so that the processing head 31 can move along a preset processing path.

[0058] In other embodiments, the moving unit 23 employs a robotic arm or a five-axis machine tool. The robotic arm or the five-axis machine tool drives the moving base 21 and the connecting plate 22 to move together, thereby realizing multi-degree-of-freedom movement of the processing head 31 to adapt to the complex movement path of the processing head 31 and improving the scope of use.

[0059] In some embodiments, there are multiple side holes 311. The first wire outlet hole 312 is communicated with the side holes 311. Different types and specifications of prepreg filaments are placed in each side hole 311. According to the needs of the target part, prepreg filaments of different grades and specifications are simultaneously selected and fed into different side holes 311, achieving combined printing of multiple filaments, enabling synchronous coupling printing of multiple fibers, and forming an integral forming of a hybrid fiber reinforced composite material. One end of the guiding tube 43 is located at the wire outlet position of the wire feeding motor, and the other end faces the side hole 311. Moreover, the first wire outlet hole 312 is located on the extending direction of the guiding tube 43, and the angle between the guiding tube 43 and the horizontal plane is 60 - 70°. By designing multiple side holes 311, each side hole 311 corresponding to a wire feeding assembly 4, the multiple wire feeding assemblies 4 can respectively feed filaments of continuous fiber reinforced composite materials of different models into the corresponding side holes 311 of the processing head 31. Under the coordinated action of their respective wire feeding mechanisms, they can be synchronously fed into the first wire outlet hole 312 of the processing head 31, and synchronous melting and compaction of filaments of multiple specifications can be achieved. The operation is simple and the forming effect is good, achieving the purpose of synchronous coupling printing of multiple materials. By having one end of the guiding tube 43 located at the wire outlet position of the wire feeding motor and the other end facing the side hole 311, and the first wire outlet hole 312 being located on the extending direction of the guiding tube 43, the wire feeding position of the filament is very stable, improving the manufacturing precision and avoiding affecting the forming process. By setting the angle between the guiding tube 43 and the horizontal plane to be 60 - 70°, the guiding effect on the filament is the best, and the filament can be better guided into the side hole 311 and the first wire outlet hole 312 in sequence.

[0060] In some embodiments, a wire feeding hole 421 and a second wire outlet hole 422 are provided on the wire feeding bracket 42. The wire on the wire feeding reel 41 passes through the wire feeding hole 421 and exits through the second wire outlet hole 422 and then enters the guiding tube 43. The wire feeding assembly 4 further includes two wire feeding rollers 44 rotatably mounted on the wire feeding bracket 42. The wire feeding motor is drivingly connected to one of the wire feeding rollers 44. The two wire feeding rollers 44 clamp the wire and are used to pull the wire to be released from the wire feeding reel 41 and move it into the guiding tube 43 to supply wire to the first wire outlet hole 312. By clamping the wire with the two wire feeding rollers 44 and drivingly connecting the wire feeding motor to one of the wire feeding rollers 44, during the rotation of the wire feeding rollers, the wire is pulled to be released from the wire feeding reel 41 and move into the guiding tube 43 to supply wire to the first wire outlet hole 312. When the wire feeding motor stops rotating, the wire feeding can be immediately stopped, and the wire can be clamped and fixed. This wire feeding method is simple and reliable, ensuring the continuous progress of processing and being more convenient and fast to stop processing.

[0061] In some embodiments, the print head assembly 3 further includes a mounting frame 33. The mounting frame 33 is connected to the connecting plate 22. A hollow structure is provided on the mounting frame 33, and the heating block 32 is mounted on the hollow structure and is thermally connected to the processing head 31. The mounting frame 33 and the connecting plate 22 can be connected by bolts. A hollow structure is provided in the middle of the mounting frame 33, which can reduce the weight of the print head assembly 3 and at the same time enable the connection wires of the heating block 32 to pass through.

[0062] In some embodiments, the print head assembly 3 further includes a pressure sensor mounted above the heating block 32. The pressure sensor is used to monitor the pressure value received by the processing head 31 and feed back the pressure value to the control device to control the processing head 31 to maintain the pressing force between the wire and the printing platform 11 or the deposited layer. By applying pressure to the processing head 31 through the force control mechanism, the control device controls the pressure applied by the force control mechanism according to the pressure value detected by the pressure sensor received by the processing head 31, so as to keep the pressing force between the processing head 31 and the wire and the printing platform 11 or the deposited layer constant. During the process of pressing the wire, the processing head 31 is heated and raised in temperature by the heating block 32, and the wire is melted and compacted at the first wire outlet hole 312, realizing the synchronous coupling 3D printing of the heterogeneous continuous fiber reinforced composite prepreg wire.

[0063] Based on the same concept, in the second aspect embodiment of the present invention, in combination with Figure 7 as shown, a 3D printing method for heterogeneous continuous fiber reinforced composites is provided. Using the 3D printing device for heterogeneous continuous fiber reinforced composites as described in the first aspect embodiment, it includes:

[0064] Step S1: Install the continuous carbon fiber reinforced PLA prepreg composite material on the wire feeding reel 41;

[0065] In step S1, PLA is the abbreviation of Polylactic Acid, and its Chinese name is polylactic acid, also known as poly(lactic acid);

[0066] Step S2: Control the moving mechanism 2 to drive the processing head 31 through the control device, so that the processing head 31 moves above the printing platform 11, maintains a set layer height spacing from the printing platform 11 or the deposited layer, and passes the front end of the wire through the side hole 311 and the first wire outlet hole 312;

[0067] Step S3: Control the wire feeding motor to drive the wire on the wire feeding reel 41 to move into the guiding tube 43 through the control device;

[0068] Step S4: Control the moving device to drive the processing head 31 to move along a given path through the control device, and control the processing head 31 to maintain a constant pressing force on the wire passing through the first wire outlet hole 312;

[0069] Step S5: Control the heating block 32 to heat the processing head 31 and the wire during the process that the processing head 31 presses the wire passing through the first wire outlet hole 312 onto the printing platform 11 or the deposited layer, so as to realize the synchronous melting and compaction of the wire.

[0070] In some embodiments, the wire feeding speed at which the wire feeding motor drives the wire on the wire feeding reel 41 to move into the guiding tube 43 is 120 - 240 mm / min; the temperature at which the heating block 32 heats the processing head 31 and the wire is 175 - 205 °C; the thickness of each deposited layer is 0.12 - 0.22 mm.

[0071] Experimental Example 1

[0072] The wire feeding speed is 200 mm / min, the temperature at which the heating block 32 heats the processing head 31 and the wire is 195 °C, and the parameter settings of the thickness of each deposited layer are shown in Table 1. The following four groups of experiments were carried out:

[0073] Table 1

[0074]

[0075] Products were obtained according to the above experimental parameters, and the bending strength and bending modulus of the products were tested. The relationship between the obtained bending strength and bending modulus and the layer thickness is shown in Table 2:

[0076] Table 2

[0077]

[0078] Experimental Example 2

[0079] The wire feeding speed is 200 mm / min, and the thickness of each deposition layer is 0.15 mm. The parameter settings of the temperature of the heating block 32 for heating the processing head 31 and the wire are shown in Table 3. The following four groups of experiments were carried out:

[0080] Table 3

[0081]

[0082] Products were obtained according to the above experimental parameters, and the bending strength and bending modulus of the products were tested. The relationship between the obtained bending strength and bending modulus and the temperature is shown in Table 4:

[0083] Table 4

[0084]

[0085] Experimental Example 3

[0086] The thickness of each deposition layer is 0.15 mm. The temperature of the heating block 32 for heating the processing head 31 and the wire is 195 °C. The parameter settings of the wire feeding speed are shown in Table 5. The following four groups of experiments were carried out:

[0087] Table 5

[0088]

[0089] Products were obtained according to the above experimental parameters, and the bending strength and bending modulus of the products were tested. The relationship between the obtained bending strength and bending modulus and the temperature is shown in Table 6:

[0090] Table 6

[0091]

[0092] The above test results were plotted as line graphs to obtain as shown in Figure 7 and Figure 8 , and the formed products with deposition layer thicknesses of 0.12 mm and 0.15 mm were photographed to obtain Figure 10 , Figure 10 Among them, (a) is a photo of the formed product with a thickness of 0.15 mm, and (b) is a photo of the formed product with a thickness of 0.12 mm. It can be seen from the figure that the bending strengths of the deposition layer thicknesses of 0.12 mm and 0.15 mm are comparable, and there is a difference in the bending modulus. However, the formed surface quality of 0.15 mm is better and smoother. The more optimal value of the deposition layer thickness is taken as 0.15 mm; when the heating temperature is 195 °C, the bending strength and bending modulus are the best; when the wire feeding speed is 200 mm / min, the bending strength and bending modulus are the best.

[0093] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A 3D printing device for a heterogeneous continuous fiber reinforced composite material, characterized in that, It includes a frame, a moving mechanism, a print head assembly, a wire feeding assembly, and a control device, where: A printing platform is provided on the frame, and the printing platform is equipped with a preheating device; The moving mechanism is installed on the frame; The print head assembly includes a processing head and a heating block. The processing head is provided with a first wire outlet hole and a plurality of side holes for the wire to enter. The first wire outlet hole is located at the bottom surface of the processing head. The side holes are close to the first wire outlet hole at the bottom surface of the processing head in the height direction of the processing head. The wires entering through the plurality of side holes all pass through the first wire outlet hole. The processing head is connected to the moving mechanism to press the wire passing through the first wire outlet hole against the printing platform or the deposited layer under the drive of the moving mechanism. The heating block is connected to the processing head and is used to preheat the wire between the side holes and the first wire outlet hole without melting it, and heat and melt the wire when the processing head presses the wire passing through the first wire outlet hole. Different types of prepreg wires are placed in each side hole, and the first wire outlet hole is communicated with the side holes. The print head assembly further includes a pressure sensor installed above the heating block. The pressure sensor is used to monitor the pressure value received by the processing head and feedback the pressure value to the control device to control the processing head to maintain the pressing force between the wire and the printing platform or the deposited layer; The wire feeding assembly includes a wire feeding reel, a wire feeding bracket, a wire feeding motor, and a guiding tube. The wire feeding reel is rotatably installed on the frame. The wire feeding bracket is connected to the moving mechanism. The wire feeding motor is installed on the wire feeding bracket and is used to drive the wire on the wire feeding reel to move into the guiding tube. The guiding tube is installed on the wire feeding bracket and is used to sequentially guide the wire into the side holes and the first wire outlet hole. One end of the guiding tube is located at the wire outlet position of the wire feeding motor, and the other end faces the side holes, and the first wire outlet hole is located in the extending direction of the guiding tube; The control device is electrically connected to the moving mechanism, the heating block, and the wire feeding motor.

2. The 3D printing device for the heterogeneous continuous fiber reinforced composite material according to claim 1, wherein, The moving mechanism includes a connecting plate, a moving base, and a moving unit. The connecting plate is respectively connected to the processing head and the wire feeding bracket. The moving base is respectively connected to the moving unit and the connecting plate and is used to drive the connecting plate to move with multiple degrees of freedom under the drive of the moving unit.

3. The 3D printing device for the heterogeneous continuous fiber reinforced composite material according to claim 2, characterized in that, The moving unit includes an X-axis, a Y-axis, a Z-axis, and three driving members. The X-axis and the Y-axis are slidably arranged on the frame. The Z-axis is respectively connected to the moving base and the connecting plate. The moving base is slidably installed on the X-axis and the Y-axis. The three driving members are installed on the moving base and are respectively used to drive the moving base to move along the X-axis and the Y-axis, and the connecting plate to move along the Z-axis.

4. The 3D printing device for heterogeneous continuous fiber reinforced composite materials according to claim 2, characterized in that, The moving unit adopts a robotic arm or a five-axis machine tool.

5. The 3D printing device for heterogeneous continuous fiber reinforced composite materials according to claim 1, characterized in that, The wire feeding bracket is provided with a wire inlet hole and a second wire outlet hole. The wire on the wire feeding reel passes through the wire inlet hole and then passes through the second wire outlet hole and enters the guiding tube; The wire feeding assembly further includes two wire feeding rollers rotatably mounted on the wire feeding bracket. The wire feeding motor is drivingly connected to one of the wire feeding rollers. The two wire feeding rollers clamp the wire and are used to pull the wire from the wire feeding reel and move it into the guiding tube to supply the wire to the first wire outlet hole.

6. The 3D printing device for the heterogeneous continuous fiber reinforced composite material according to claim 2, wherein, The printing head assembly further includes a mounting frame. The mounting frame is connected to the connecting plate. The mounting frame is provided with a hollow structure. The heating block is mounted on the hollow structure and is thermally connected to the processing head.

7. A 3D printing method for a heterogeneous continuous fiber reinforced composite material, using the 3D printing device for a heterogeneous continuous fiber reinforced composite material according to any one of claims 1-6, characterized in that, Comprising: Controlling, by a control device, the moving mechanism to drive the processing head so that the processing head moves above the printing platform and maintains a set layer height spacing from the printing platform or the deposited layer, and passing the front end of the wire through the side hole and the first wire outlet hole; Controlling, by a control device, the wire feeding motor to drive the wire on the wire feeding reel to move into the guiding tube; Controlling, by a control device, the moving device to drive the processing head to move along a given path and controlling the processing head to maintain a constant pressing force on the wire passing through the first wire outlet hole; Controlling, by a control device, the heating block to heat the processing head and the wire during the process that the processing head presses the wire passing through the first wire outlet hole onto the printing platform or the deposited layer, so as to realize synchronous melting and compaction of the wire.

8. The 3D printing method of the heterogeneous continuous fiber reinforced composite material according to claim 7, wherein, The wire feeding speed at which the wire feeding motor drives the wire on the wire feeding reel to move into the guiding tube is 120 - 240 mm / min; the temperature at which the heating block heats the processing head and the wire is 175 - 205 °C; the thickness of each deposited layer is 0.12 - 0.22 mm.

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