Single-jet dual-material 3D printer

Abstract

The application discloses a single-nozzle double-material 3D printer. A transmission device is installed on an aluminum shell, a double-material melting device is installed on the transmission system, a printing heating platform is horizontally installed on the bottom surface of the aluminum shell and is located directly below the double-material melting device, a material supply device is installed on the lateral surface of the aluminum shell and is connected with the double-material melting device through a feeding pipe, the double-material melting device is connected with an external air pump through a blowing pipe; a power supply and a control mainboard are installed in the aluminum shell, the double-material melting device is electrically connected with the power supply, and the power supply, the transmission device, the printing heating platform and the material supply device are electrically connected with the control mainboard. The 3D printer can realize the printing mode of multiple materials, can realize seamless connection during the switching of multiple materials, can make the printed support structure be taken out more easily, can reduce the weight of the nozzle, can improve the moving accuracy and can reduce the interlayer disorder.

Description

TECHNICAL FIELD

[0001] The application relates to a 3D printer, in particular to a single-nozzle double-material 3D printer. BACKGROUND

[0002] Currently, 3D printing technology is often used in the industry and art field to produce non-standard parts. However, the traditional 3D printer often uses a double-nozzle forming form or a single-material discharging mode, and has the problems of heavy weight, slow acceleration, low production efficiency, single material, difficult support structure removal and easy layer disorder of the parts. SUMMARY

[0003] In order to solve the problems in the background art, the application provides a single-nozzle double-material 3D printer.

[0004] The technical scheme adopted by the application is:

[0005] The single-nozzle double-material 3D printer comprises an aluminum shell, a transmission system, a double-material melting device, a printing heating platform, a material supply device, a power supply and a control mainboard. The transmission device is installed on the aluminum shell, the double-material melting device is installed on the transmission system, the printing heating platform is horizontally installed on the inner bottom surface of the aluminum shell and located directly below the double-material melting device, the material supply device is installed on the outer side surface of the aluminum shell and connected with the double-material melting device through a feeding pipe, and the double-material melting device is connected with an external air pump through a blowing pipe. The power supply and the control mainboard are installed in the aluminum shell, the double-material melting device is electrically connected with the power supply, and the power supply, the transmission device, the printing heating platform and the material supply device are electrically connected with the control mainboard.

[0006] The aluminum shell is a cubic shell, and a second linear guide rail is installed on each of the four vertical edges in the aluminum shell. The aluminum shell uses an acrylic plate as a sealing panel to realize real-time observation of the printing condition. The transmission system comprises a horizontal transmission device and a vertical transmission device. The horizontal transmission device is a Core XY framework device, and the horizontal transmission device is horizontally arranged. The four corners of the horizontal transmission device are slidingly installed on the four vertical second linear guide rails in the aluminum shell, and the double-material melting device is slidingly installed on the first linear guide rail in the middle of the horizontal transmission device. The vertical transmission device comprises two vertical conveyors, which are vertically installed on the aluminum shell and close to two adjacent vertical edges of the aluminum shell. Each vertical conveyor is connected with one corner of the horizontal transmission device close thereto. The two first stepping motors of the horizontal transmission device and the two vertical conveyors are electrically connected with the control mainboard. The Core XY framework device is driven by the two first stepping motors, a second synchronous belt and synchronous wheels. The two first stepping motors in the XY shaft transmission framework are fixed at the rear end of the gantry, and the two synchronous wheels are fixed on the motor shaft to drive the second synchronous belt to move.

[0007] Each vertical conveyor comprises a first synchronous belt, an 80-tooth synchronous wheel, a third synchronous belt, a 20-tooth synchronous wheel, a 20-tooth belt tooth idler wheel and a third stepper motor, the 80-tooth synchronous wheel, the 20-tooth synchronous wheel and the third stepper motor are vertically installed at the bottom of one of the bottom corners of the aluminum shell through respective mounting frames, the 80-tooth synchronous wheel and the 20-tooth synchronous wheel are not in contact, the output shaft of the third stepper motor is synchronously connected to the central shaft of the 20-tooth synchronous wheel, the third synchronous belt is wound around the 80-tooth synchronous wheel and the 20-tooth synchronous wheel and forms a closed loop; the 20-tooth belt tooth idler wheel is vertically installed on the top surface of one of the bottom corners inside the aluminum shell through its own mounting frame and is located directly above the 80-tooth synchronous wheel, the central shaft of the 20-tooth belt tooth idler wheel and the 80-tooth synchronous wheel are located on the same vertical plane, the first synchronous belt is wound around the central shaft of the 80-tooth synchronous wheel and the 20-tooth belt tooth idler wheel and forms a closed loop, a corner sleeve close to the horizontal transmission device is sleeved on the first synchronous belt; the third stepper motor is electrically connected to the control mainboard. Rubber shock-absorbing foot pads are also installed at the bottom of the mounting frame of the 80-tooth synchronous wheel; a Z-axis position limiter is also installed on the transmission system for limiting the vertical movement position of the horizontal transmission device; the 80-tooth synchronous wheel and the 20-tooth belt tooth idler wheel jointly serve as a two-stage speed reduction mechanism.

[0008] When the horizontal transmission device is sleeved on the first synchronous belt, it is fixedly connected to one edge of the first synchronous belt and movably sleeved on the other edge; the third stepper motor drives the 20-tooth synchronous wheel to rotate and in turn drives the 80-tooth synchronous wheel to rotate through the third synchronous belt, the 80-tooth synchronous wheel drives the 20-tooth belt tooth idler wheel to rotate through the first synchronous belt, and the horizontal transmission device sleeved on the first synchronous belt moves up and down with the transmission of the first synchronous belt.

[0009] The double-material melting device comprises three pneumatic connectors, a heat dissipation pipe, a heating aluminum block, a nozzle and a second fan, the heat dissipation pipe is vertically and slidingly installed on the first linear guide rail of the horizontal transmission device, the three pneumatic connectors are installed at intervals on the top end of the heat dissipation pipe and are communicated with the heat dissipation pipe, the heat dissipation pipe is communicated with the material supply device through a respective feeding pipe through two of the pneumatic connectors, and the heat dissipation pipe is communicated with an external air pump through a respective blowing pipe through the other pneumatic connector; the second fan is installed on the outer wall surface of the heat dissipation pipe, the nozzle is installed at the bottom end of the heat dissipation pipe and is communicated with the heat dissipation pipe, the heating aluminum block is sleeved on the nozzle, and the heating aluminum block is electrically connected to the power supply. The three pneumatic connectors convert the traditional single-channel radiator into a Y-shaped three-way radiator, and the distribution positions of the three pneumatic interfaces feeding channels above the heat dissipation pipe form an equilateral triangle. The temperature of the nozzle is controlled by a PID control algorithm, and the heating device is composed of a 40W 24V electric heating rod, a thermistor and a hot end aluminum block.

[0010] The four corner bottom surfaces of the horizontal transmission device are also respectively provided with micro switches, when the nozzle of the double-material melting device moves to one of the micro switches and collides with the pop-up structure of the micro switch, the micro switch transmits the current position coordinate of the nozzle to the control mainboard.

[0011] The material supply device comprises two extruder mechanisms, each of which comprises a second stepper motor and an extruder, the second stepper motor and the extruder are installed on the outer side of the aluminum shell through respective mounting frames, and the second stepper motor is directly connected to the extruder; two different 3D printing materials are contained in the two extruders, and the extrusion outlets of the two extruders are respectively connected to two pneumatic connectors of the heat dissipation pipe through two feeding pipes.

[0012] The two different 3D printing materials in the two extruders are extruded into the two pneumatic connectors of the heat dissipation pipe through the two second stepper motors, at the same time, the external air pump introduces air flow into the other pneumatic connector of the heat dissipation pipe through the blowing pipe, the control mainboard controls the power supply to heat the aluminum block, finally, the two different 3D printing materials, i.e. A consumables and B consumables, are extruded from the nozzle to the printing heating platform below after entering the melting cavity, and the transmission system controls the material supply device to move for 3D printing.

[0013] The model of the extruder is selected as an MK8 upgraded aluminum alloy structure direct extruder, and the gear with protruding teeth is fixed on the shaft of the second stepper motor, which extrudes the wire together with the bearing with grooves and drives the wire to enter the hot end through the feeding pipe.

[0014] The printing heating platform comprises a double-sided PEI powder steel plate, a magnetic hot bed sticker, a hot bed aluminum plate and a silica gel heating pad arranged in sequence from top to bottom, the silica gel heating pad is electrically connected to the control mainboard, and the control mainboard controls the silica gel heating pad to maintain a preset temperature during printing of the 3D printer.

[0015] The side surface of the aluminum shell is also provided with a first fan, the first fan is communicated with the inside of the aluminum shell, and the first fan is electrically connected to the control mainboard. The first fan is installed at the air extraction opening arranged on the side surface of the aluminum shell, and the first fan is used to filter the toxic gas generated during printing.

[0016] The control mainboard adopts Raspberry Pi 4B as an upper computer, and adopts octopusPRO embedded system mainboard as a lower computer. The upper computer Raspberry Pi performs serial communication with the lower computer octopusPRO embedded system mainboard through USB, runs a printer system program through the Raspberry Pi and sends a running signal to the lower computer; the power socket selects an AUTOKER brand safety switch socket three-in-one power filter, and a 200W 24V switching power supply is selected for power supply; the 3D printer is also provided with a display system, the display system selects a mini12864 LCD liquid crystal display module, parameter adjustment and file selection can be realized, the Raspberry Pi obtains the printer platform temperature and the nozzle temperature of the lower computer mainboard through USB serial communication and feeds back to the mini12864 LCD liquid crystal display for display output; a sensing positioning system is also arranged, which is used for positioning the nozzle position, adjusting the parallelism between the virtual printing plane of the printer and the actual printing plane and recording the printing position in real time.

[0017] The beneficial effects of the present application are:

[0018] 1. The printing mode of multiple materials can be realized.

[0019] 2. Seamless connection during multiple material switching can be realized.

[0020] 3. The printed support structure can be more easily taken out.

[0021] 4. The weight at the nozzle can be reduced, the moving accuracy can be improved, and the interlayer disorder can be reduced. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is a front view of the printer structure of the present application.

[0023] Figure 2 It is a top view of the printer structure of the present application.

[0024] Figure 3 It is a left view of the printer structure of the present application.

[0025] Figure 4 It is a Z-axis synchronous belt transmission structure diagram of the present application.

[0026] Figure 5 It is a secondary speed reduction device schematic diagram of the present application.

[0027] Figure 6 It is an XY-axis motion diagram of the present application.

[0028] Figure 7 It is an XY-axis structure schematic diagram of the present application.

[0029] Figure 8 It is a working principle diagram of the nozzle-cold end internal passage of the present application.

[0030] In the figure: 1, aluminum shell, 2, the first synchronous belt, 3, tank chain, 4, the first stepper motor, 5, 80-tooth synchronous wheel, 6, rubber shock foot pad, 7, pneumatic joint, 8, heat dissipation pipe, 9, the second synchronous belt, 10, the first linear guide rail, 11, micro switch, 12, double-sided PEI powder steel plate, 13, magnetic hot bed paste, 14, hot bed aluminum plate, 15, silica gel heating pad, 16, the third synchronous belt, 17, 20-tooth synchronous wheel, 18, the second stepper motor, 19, extruder, 20, synchronous wheel, 21, the first fan, 22, Z-axis limiter, 23, 20-tooth belt tooth idler, 24, the second linear guide rail, 25, heating aluminum block, 26, nozzle. DETAILED DESCRIPTION

[0031] The application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] As shown in Figure 1 , Figure 2 and Figure 3 , the single-nozzle double-material 3D printer of the application comprises an aluminum shell 1, a transmission system, a double-material melting device, a printing heating platform, a material supply device, a power supply and a control mainboard. The transmission device is installed on the aluminum shell 1, the double-material melting device is installed on the transmission system, the printing heating platform is horizontally installed on the inner bottom surface of the aluminum shell 1 and located directly below the double-material melting device, the material supply device is installed on the outer lateral surface of the aluminum shell 1 and communicates with the double-material melting device through a feeding pipe, and the double-material melting device communicates with an external air pump through a blowing pipe; the power supply and the control mainboard are installed in the aluminum shell 1, the double-material melting device is electrically connected to the power supply, and the power supply, the transmission device, the printing heating platform and the material supply device are electrically connected to the control mainboard.

[0033] The printing heating platform comprises a double-sided PEI powder steel plate 12, a magnetic hot bed paste 13, a hot bed aluminum plate 14 and a silica gel heating pad 15 arranged in sequence from top to bottom. The hot bed aluminum plate 14 and the silica gel heating pad 15 are electrically connected to the control mainboard, and the control mainboard controls the silica gel heating pad 15 to maintain a preset temperature during 3D printing.

[0034] A first fan 21 is further installed on the lateral surface of the aluminum shell 1, the first fan 21 communicates with the inside of the aluminum shell 1, and the first fan 21 is electrically connected to the control mainboard. The first fan 21 is installed at an air extraction opening provided on the lateral surface of the aluminum shell 1, and the first fan 21 is used to filter toxic gases generated during printing. A tank chain 3 is further installed in the aluminum shell 1, and the tank chain 3 collects all the electrical connection lines of the 3D printer, so that the 3D printer is not affected by the electrical connection lines

[0035] The control mainboard adopts Raspberry Pi 4B as the upper computer and octopusPRO embedded system mainboard as the lower computer. The upper computer Raspberry Pi communicates with the lower computer octopusPRO embedded system mainboard through USB, runs the printer system program through the Raspberry Pi and sends the running signal to the lower computer; the power socket selects the AUTOKER brand safety switch socket three-in-one power filter, and the power supply selects a 200W 24V switching power supply for power supply; the 3D printer is also provided with a display system, the display system selects a mini12864 LCD liquid crystal display module, which can realize parameter adjustment and file selection, the Raspberry Pi obtains the printer platform temperature and nozzle temperature of the lower computer mainboard through USB serial communication and feeds back to the mini12864 LCD display for display output; a sensing positioning system is also provided for positioning the position of the nozzle 26 and adjusting the parallelism between the virtual printing plane of the printer and the actual printing plane and can record the printing position in real time.

[0036] The aluminum shell 1 is a cubic shell, and a second linear guide rail 24 is installed on each of the four vertical edges inside the aluminum shell 1, and the second linear guide rail 24 adopts an MGN9H type linear guide rail; the aluminum shell 1 adopts an acrylic plate as a sealing panel to realize real-time observation of the printing condition; the transmission system includes a horizontal transmission device and a vertical transmission device, as shown in Figure 6 and Figure 7 , the horizontal transmission device is specifically a Core XY architecture device, the horizontal transmission device is horizontally arranged, the four corners of the horizontal transmission device are slidingly installed on the four vertical second linear guide rails 24 inside the aluminum shell 1, and a double-material melting device is slidingly installed on the first linear guide rail 10 in the middle of the horizontal transmission device; the vertical transmission device includes two vertical conveyors, the two vertical conveyors are vertically installed on the aluminum shell 1 and close to two adjacent vertical edges of the aluminum shell 1, and each vertical conveyor is connected to one corner of the horizontal transmission device close thereto; the two first stepping motors 4 of the horizontal transmission device and the two vertical conveyors are electrically connected to the control mainboard. The Core XY architecture device is driven by the two first stepping motors 4, the second synchronous belt 9 and the synchronous wheel 20 thereof; the two first stepping motors 4 in the XY axis transmission architecture are fixed at the rear end of the gantry, and the two synchronous wheels 20 are fixed on the motor shaft to drive the second synchronous belt 9 to move. Two MGN9H type linear guide rails and optical shafts are selected in the horizontal transmission device to assist in supporting and guiding, and the first linear guide rail 10 in the middle selects an MGN12H linear guide rail.

[0037] As shown in Figure 4 and Figure 5As shown, each vertical conveyor comprises a first synchronous belt 2, an 80-tooth synchronous wheel 5, a third synchronous belt 16, a 20-tooth synchronous wheel 17, a 20-tooth belt tooth idler wheel 23 and a third stepper motor, the 80-tooth synchronous wheel 5, the 20-tooth synchronous wheel 17 and the third stepper motor are vertically installed at one bottom corner of the aluminum shell 1 through respective mounting frames, the 80-tooth synchronous wheel 5 and the 20-tooth synchronous wheel 17 are not in contact, the output shaft of the third stepper motor is synchronously connected with the central shaft of the 20-tooth synchronous wheel 17, and the third synchronous belt 16 is wound around the 80-tooth synchronous wheel 5 and the 20-tooth synchronous wheel 17 and forms a closed loop; the 20-tooth belt tooth idler wheel 23 is vertically installed at the top surface of one bottom corner inside the aluminum shell 1 through its own mounting frame and is located directly above the 80-tooth synchronous wheel 5, the 20-tooth belt tooth idler wheel 23 and the central shaft of the 80-tooth synchronous wheel 5 are located on the same vertical plane, the first synchronous belt 2 is wound around the central shaft of the 80-tooth synchronous wheel 5 and the 20-tooth belt tooth idler wheel 23 and forms a closed loop, and a corner sleeve of the horizontal transmission device close to the vertical conveyor is sleeved on the first synchronous belt 2; the third stepper motor is electrically connected with the control mainboard. The mounting frame of the 80-tooth synchronous wheel 5 is further provided with a rubber shock-absorbing foot pad 6; a Z-axis limiter 22 is further installed on the transmission system for limiting the vertical movement position of the horizontal transmission device; the 80-tooth synchronous wheel 5 and the 20-tooth belt tooth idler wheel 23 jointly serve as a two-stage speed reduction mechanism. The first synchronous belt 2 is a GT-2-10mm arc-shaped synchronous belt; the second synchronous belt 9 is a GT2-6mm arc-shaped synchronous belt; and the motor is a motor with a model number of 17HS19-2004S1.

[0038] When the horizontal transmission device is sleeved on the first synchronous belt 2, one edge of the first synchronous belt 2 is fixedly connected, and the other edge is movably sleeved; the third stepper motor drives the 20-tooth synchronous wheel 17 to rotate and then drives the 80-tooth synchronous wheel 5 to rotate through the third synchronous belt 16, the 80-tooth synchronous wheel 5 drives the 20-tooth belt tooth idler wheel 23 to rotate through the first synchronous belt 2, and the horizontal transmission device sleeved on the first synchronous belt 2 moves up and down with the transmission of the first synchronous belt 2.

[0039] The double-material melting device comprises three pneumatic joints 7, a heat dissipation pipe 8, a heating aluminum block 25, a nozzle 26 and a second fan, the heat dissipation pipe 8 is vertically and slidingly installed on the first linear guide rail 10 of the horizontal transmission device, the three pneumatic joints 7 are installed at the top of the heat dissipation pipe 8 in a spaced manner and are communicated with the heat dissipation pipe 8, the heat dissipation pipe 8 is communicated with the material supply device through a respective feeding pipe via two of the pneumatic joints 7, and the heat dissipation pipe 8 is communicated with an external air pump through a respective blowing pipe via the other pneumatic joint 7; the second fan is installed on the outer wall surface of the heat dissipation pipe 8, the nozzle 26 is installed at the bottom of the heat dissipation pipe 8 and is communicated with the heat dissipation pipe 8, the heating aluminum block 25 is sleeved on the nozzle 26, and the heating aluminum block 25 is electrically connected with a power supply.

[0040] Microswitches 11 are further installed at the bottom of the four corners of the horizontal transmission device, respectively, when the nozzle 26 of the double-material melting device moves to one of the microswitches 11 and collides with the pop-up structure of the microswitch 11, the microswitch 11 transmits the current position coordinates of the nozzle 26 to the control mainboard.

[0041] After the current position coordinates of the nozzle 26 are obtained by the microswitches 11, it can be judged whether the nozzle 26 needs to be leveled, and then the position of the nozzle 26 is corrected to ensure that the working plane and the hot bed plane remain parallel; the microswitches 11 are normally closed switches.

[0042] The material supply device comprises two extruder mechanisms, each of which comprises a second stepper motor 18 and an extruder 19, the second stepper motor 18 and the extruder 19 are installed on the outer side surface of the aluminum shell 1 through respective mounting frames, and the second stepper motor 18 is directly connected with the extruder 19; two different 3D printing materials are contained in the two extruders 19, and the extrusion outlets of the two extruders 19 are respectively communicated with two pneumatic joints 7 of the heat dissipation pipe 8 through two feeding pipes.

[0043] As shown in Figure 8 , the two different 3D printing materials in the two extruders 19 are extruded into two pneumatic joints 7 of the heat dissipation pipe 8 through two second stepper motors 18, at the same time, an external air pump blows air into the other pneumatic joint 7 of the heat dissipation pipe 8 through a blowing pipe, a control mainboard controls a power supply to heat the heating aluminum block 25, finally, two different 3D printing materials, i.e. A consumables and B consumables, enter the melting cavity and are extruded by the nozzle 26 to the printing and heating platform below, and a transmission system controls the material supply device to move for 3D printing.

[0044] The extruder 19 is an upgraded version of the MK8 aluminum alloy direct extruder, and uses a gear with convex teeth fixed on the shaft of the second stepper motor 18. Together with the grooved bearing, it extrudes the filament and drives the filament into the hot end through the feed pipe. Both the feed pipe and the air blowing pipe are made of Teflon tubing with an inner diameter of 2mm and an outer diameter of 4mm.

[0045] The first synchronous belt 2 is 9mm wide, the second synchronous belt 9 is 6mm wide, the heated bed aluminum plate 14 is 300*300mm in size, the third synchronous belt 16 is 6mm wide, the 20-tooth synchronous pulley 17 has an inner diameter of 5mm and a width of 9mm, and the synchronous pulley 20 has an inner diameter of 5mm and a width of 6mm.

[0046] like Figure 6 and Figure 7 As shown, the Core XY architecture is driven and controlled by two first-step motors 4 arranged on the moving plane of the nozzle 26. When the left and right motors move in the same direction, the nozzle will move along the X-axis; when the left and right motors move in opposite directions, the nozzle will move along the Y-axis. During printing, the two materials can be extruded and retracted from the two pneumatic joints 7 on the left and right through the extruder 19 at the top of the 3D printer. When changing materials, the extruder 19 reverses, and the filament returns to the three-way junction. At this time, the heating rod in the heated aluminum block 25 maintains a constant melting temperature, and the micro air pumps in the three channels start working to blow out the remaining molten waste.

[0047] Existing 3D printers also use an extruder to extrude filaments for printing, but they often use dual nozzles to eject materials, which can easily lead to uneven mixing of multiple materials and poor printing results. In this invention, a three-in-one-out design is adopted. The extruder reverses to return the filaments to the intersection of the three channels, and the remaining waste material in the molten chamber is blown out by a micro air pump.

Claims

1. A single-jet dual-material 3D printer, characterized by: The application relates to a 3D printer, which comprises an aluminum shell (1), a transmission system, a double-material melting device, a printing heating platform, a material supply device, a power supply and a control mainboard, the transmission system is installed on the aluminum shell (1), the double-material melting device is installed on the transmission system, the printing heating platform is horizontally installed on the bottom surface in the aluminum shell (1) and is located directly below the double-material melting device, the material supply device is installed on the lateral surface of the aluminum shell (1) and is connected with the double-material melting device through a feeding pipe, the double-material melting device is connected with an external air pump through a blowing pipe, the power supply and the control mainboard are installed in the aluminum shell (1), the double-material melting device is electrically connected with the power supply, and the power supply, the transmission system, the printing heating platform and the material supply device are electrically connected with the control mainboard. The double-material melting device comprises three pneumatic joints (7), a heat dissipation pipe (8), a heating aluminum block (25), a nozzle (26) and a second fan, the heat dissipation pipe (8) is vertically and slidingly installed on a first linear guide rail (10) of the horizontal transmission device, the three pneumatic joints (7) are spaced apart and installed on the top end of the heat dissipation pipe (8) and are connected with the heat dissipation pipe (8), the heat dissipation pipe (8) is connected with the material supply device through two feeding pipes of the two pneumatic joints (7) respectively, and the heat dissipation pipe (8) is connected with the external air pump through the blowing pipe of the other pneumatic joint (7); the second fan is installed on the outer wall surface of the heat dissipation pipe (8), the nozzle (26) is installed on the bottom end of the heat dissipation pipe (8) and is connected with the heat dissipation pipe (8), and the heating aluminum block (25) is sleeved on the nozzle (26) and is electrically connected with the power supply. The material supply device comprises two extruder mechanisms, each extruder mechanism comprises a second stepping motor (18) and an extruder (19), the second stepping motor (18) and the extruder (19) are installed on the lateral surface of the aluminum shell (1) through respective mounting racks, and the second stepping motor (18) is directly connected with the extruder (19); two different 3D printing materials are contained in the two extruders (19), and the extrusion outlets of the two extruders (19) are connected with the two pneumatic joints (7) of the heat dissipation pipe (8) through two feeding pipes respectively. The two different 3D printing materials in the two extruders (19) are extruded into the two pneumatic joints (7) of the heat dissipation pipe (8) through the two second stepping motors (18), meanwhile, the external air pump introduces air flow into the other pneumatic joint (7) of the heat dissipation pipe (8) through the blowing pipe, the control mainboard controls the power supply to heat the heating aluminum block (25), and finally the two different 3D printing materials enter the melting cavity and are extruded by the nozzle (26) to realize 3D printing; when the materials are replaced, a three-in-one-out design mode is adopted, the filaments are returned to the three-channel intersection through the reverse rotation of the extruder (19), at this time, the heating aluminum block (25) keeps the melting temperature unchanged, and the micro air pumps in the three channels start to work to blow out the remaining waste materials.

2. The single-jet dual-material 3D printer of claim 1, wherein: The aluminum material shell (1) is a cubic shell, and a second linear guide rail (24) is installed on each of the four vertical edges inside the aluminum material shell (1); the transmission system comprises a horizontal transmission device and a vertical transmission device, the horizontal transmission device is a Core XY framework device, the horizontal transmission device is horizontally arranged, four corners of the horizontal transmission device are slidingly installed on the four vertical second linear guide rails (24) inside the aluminum material shell (1), and a double-material melting device is slidingly installed on a first linear guide rail (10) in the middle of the horizontal transmission device; the vertical transmission device comprises two vertical conveyors, the two vertical conveyors are vertically installed on the aluminum material shell (1) and close to two adjacent vertical edges of the aluminum material shell (1), and each vertical conveyor is connected to a corner of the horizontal transmission device close thereto; two first stepping motors (4) of the horizontal transmission device and the two vertical conveyors of the vertical transmission device are electrically connected to a control mainboard.

3. The single-jet dual-material 3D printer of claim 2, wherein: Each vertical conveyor comprises a first synchronous belt (2), an 80-tooth synchronous wheel (5), a third synchronous belt (16), a 20-tooth synchronous wheel (17), a 20-tooth belt tooth idler wheel (23) and a third stepping motor, the 80-tooth synchronous wheel (5), the 20-tooth synchronous wheel (17) and the third stepping motor are vertically installed on a bottom corner of the aluminum material shell (1) through respective mounting frames, the 80-tooth synchronous wheel (5) and the 20-tooth synchronous wheel (17) are not in contact, the output shaft of the third stepping motor is synchronously connected to the central shaft of the 20-tooth synchronous wheel (17), the third synchronous belt (16) is wound around the 80-tooth synchronous wheel (5) and the 20-tooth synchronous wheel (17) to form a closed loop, the 20-tooth belt tooth idler wheel (23) is vertically installed on the top surface of the bottom corner inside the aluminum material shell (1) and directly above the 80-tooth synchronous wheel (5) through a mounting frame thereof, the 20-tooth belt tooth idler wheel (23) and the central shaft of the 80-tooth synchronous wheel (5) are located on the same vertical plane, the first synchronous belt (2) is wound around the central shaft of the 80-tooth synchronous wheel (5) and the 20-tooth belt tooth idler wheel (23) to form a closed loop, and a corner of the horizontal transmission device close to the vertical conveyor is sleeved on the first synchronous belt (2); the third stepping motor is electrically connected to the control mainboard.

4. The single-jet dual-material 3D printer of claim 1, wherein: The bottom surface of each corner of the horizontal transmission device is further provided with a micro switch (11), when the nozzle (26) of the double-material melting device moves to one of the micro switches (11) and collides with the pop-up structure of the micro switch (11), the micro switch (11) transmits the current position coordinates of the nozzle (26) to the control mainboard.

5. The single-jet dual-material 3D printer of claim 1, wherein: The printing heating platform comprises, from top to bottom, a double-sided PEI powder steel plate (12), a magnetic hot bed sticker (13), a hot bed aluminum plate (14) and a silica gel heating pad (15), the hot bed aluminum plate (14) and the silica gel heating pad (15) are electrically connected to the control mainboard, and the control mainboard controls the silica gel heating pad (15) to maintain a preset temperature during 3D printer printing.

6. The single-jet dual-material 3D printer of claim 1, wherein: The side surface of the aluminum material shell (1) is further provided with a first fan (21), the first fan (21) is communicated with the inside of the aluminum material shell (1), and the first fan (21) is electrically connected to the control mainboard.

7. The single-jet dual-material 3D printer of claim 1, wherein: The control mainboard adopts Raspberry Pi 4B as an upper computer and adopts octopusPRO embedded system mainboard as a lower computer.

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