A method for detecting and unclogging nozzle blockage in 3D printing

Abstract

The present invention provides a method for detecting and unblocking nozzle blockage in 3D printing, comprising a nozzle, a material guide pipe, an extruder, an air pipe, and an air compressor. The nozzle is connected to a material guide pipe above the nozzle, and the material guide pipe is connected to an extruder above the nozzle. One end of the extruder is connected to the air compressor through an air pipe. The present invention determines whether a wire blockage has occurred in the nozzle by continuously monitoring the current of a stepper motor. After confirming that the wire blockage has occurred, the nozzle is heated to a high temperature state of 250°C. After confirming that the wire blockage has occurred, the nozzle is heated, and gas pressure is accumulated through an air compressor. After the pressure accumulation is completed, the compressed air is released to achieve an unblocking effect. After the pressure accumulation is completed, the compressed air is quickly released and sent into the nozzle through the air pipe and the material guide pipe to directly impact the blocked part. This process is repeated until the blockage is completely cleared.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printing, and in particular to a method for detecting and clearing nozzle blockage in 3D printing. Background Art

[0002] 3D printing technology is a rapid prototyping technology. Different from the traditional subtractive manufacturing methods of cutting and stamping, 3D printers produce parts based on the principle of additive manufacturing. It has a wide range of applications and huge market value in industrial design, education, architecture, aerospace, dentistry and other fields of the medical industry.

[0003] Among the many types of 3D printing processes, Fused Deposition Modeling (FDM) is the most commonly used one. Fused deposition modeling technology uses hot-melt filamentary materials (PLA, ABS, etc.) as printing consumables. The material is heated by a nozzle to reach a molten state, and then accumulated, cooled, and solidified on the printing platform along the slicing path, thus forming a three-dimensional entity layer by layer.

[0004] In the prior art, nozzle blockage is an important factor that hinders the smooth progress of printing. After the wire is blocked, it is difficult for the printing program to find the coordinate point where the wire is not normally output, resulting in the printing program being unable to continue printing after the work before the wire blockage. Once the nozzle is blocked, it may cause the model that has been printed for several hours to be destroyed, and it is more likely to cause the extruder motor to be overloaded and damaged, ultimately resulting in a waste of time and materials. Considering the comprehensive stability and economy, there are many machines on the market that use manual machinery to disassemble and unblock the machine. However, manual disassembly will inevitably bring about problems such as troublesome operation process, easily damaged parts, and reduced device life.

[0005] At present, due to the advantages of simple structure and low cost, the popularity of 3D printers based on the FDM principle has increased. At the same time, more and more users are troubled by the problem of easy nozzle clogging of 3D printers based on the FDM principle during work.

[0006] In the existing FDM printing process, there is usually a phenomenon of long single working time, which causes the print head to overheat. When the filament is fed into the print head, the temperature of the wire inlet is too high, resulting in a decrease in the rigidity of the wire. The wire cannot smoothly extrude the molten material in the nozzle, eventually leading to nozzle blockage. In addition, the high-melting-point impurities in the wire are not fully melted, resulting in a gradual increase in the wire outlet resistance, which eventually leads to nozzle blockage.

[0007] Therefore, there is an urgent need for a 3D printed nozzle blockage detection and unblocking method. Summary of the invention

[0008] In view of this, in order to solve the problems existing in the technical background, the present invention proposes a method for detecting and unblocking nozzle blockage in 3D printing, and the specific technical solution is as follows:

[0009] A method for detecting and unblocking nozzle blockage in 3D printing comprises a nozzle, a material guide pipe, an extruder, an air pipe and an air compressor, wherein the nozzle is connected with a material guide pipe above, the material guide pipe is connected with an extruder above, one end of the extruder is connected to the air compressor through an air pipe, gas is pressurized by the air compressor, and after the pressure is accumulated, the compressed air is released, and the compressed air is sent into the nozzle through the material guide pipe to impact the blocked part for unblocking; a heating block is sleeved above the nozzle for heating the nozzle, and the 3D printing consumables inside the nozzle are fully heated and melted by heat conduction and then discharged through the wire-extruding process.

[0010] In one embodiment of the present invention, the air compressor includes a deflation valve body, a sealing valve body, a compressed air bottle, a cylinder, and a motor. The deflation valve body is arranged on the air pipe near the extruder, the sealing valve body is arranged on the material guide pipe between the extruder and the nozzle, the cylinder is connected to one end of the air pipe, a pressure gauge is provided on the cylinder, a rotating pressure gauge pointer is provided in the pressure gauge, one end of the air pipe is also connected to the cylinder, and the cylinder is connected to the motor through a transmission mechanism.

[0011] In one embodiment of the present invention, in one embodiment of the present invention, the transmission mechanism includes a first driving gear, a first driven gear, a crankshaft, a motor, a crankshaft connecting rod, a bracket, a piston, a crankpin and a shaft; the motor is arranged below the bracket, the output end of the motor passes through the bracket and is connected to the first driving gear, the first driving gear is connected to the first driven gear by meshing, the diameter of the first driven gear is larger than the diameter of the first driving gear, the center of the first driven gear is connected to the shaft, the outside of the shaft is sleeved with a crankshaft, the bottom of the crankshaft is fan-shaped, a protrusion is provided on the top of the crankshaft, the protrusion is connected to the crankpin, the crankpin is connected to the crankshaft connecting rod, a through hole is opened at one end of the crankshaft connecting rod, a piston pin is provided in the through hole, and the piston pin and the upper part of the crankshaft connecting rod are arranged in the piston.

[0012] In one embodiment of the present invention, a heat sink is provided above the heating block, and the heat sink is sleeved on the nozzle to dissipate heat generated by the nozzle during operation.

[0013] In one embodiment of the present invention, the extruder includes a stepper motor, a booster push rod, a spring, a pressure arm, a second driving gear, and a second driven gear. The output end of the stepper motor is connected to the second driving gear, and the second driving gear is connected to the second driven gear by meshing. The output end of the second driven gear is connected to an extrusion wheel, and an output guide plate is provided obliquely below the extrusion wheel, and an output end guide block is provided below the output guide plate. A sealing valve body is provided below the output end guide block, and an input end guide block is provided above the inside of the sealing valve body, and an output end guide block is provided below the input end guide block. A semi-cylindrical groove is provided at the bottom of the input end guide block, and a sealing valve is provided in the semi-cylindrical groove. The diameter of the sealing valve is the same as the diameter of the semi-cylindrical groove. The sealing valve is connected to an electromagnet core, and an electromagnet is provided outside the electromagnet core, and the electromagnet is fixed on the electromagnet fixing block.

[0014] In one embodiment of the present invention, the model of the single chip microcomputer is STC12C5A60.

[0015] In one embodiment of the present invention, the model of the optical sensor is ADNS-2030.

[0016] The above technical solution has the following beneficial effects:

[0017] The present invention determines whether wire blockage has occurred in the nozzle by continuously monitoring the welding wire speed of the photoelectric sensor or monitoring the power of the stepper motor and other conditions. After confirming that wire blockage has occurred, the nozzle is heated to a high temperature state of 250°C. This temperature is set according to the melting point of most 3D printing consumables to ensure that the consumables can be fully melted to prepare for subsequent unblocking operations.

[0018] The present invention controls the sealing valve body through an electromagnet, so that when the printer is working normally, the consumables can pass through the sealing valve body normally, and when the dredging work is needed, the air path is sealed so that the compressed air can fully impact the blocked part of the nozzle. Based on compressed gas to achieve unblocking, an air compressor is connected to one end of the extruder, and the air compressor includes a vent valve body, a sealing valve body, a compressed air bottle, a cylinder, a motor, etc. When the dredging work is needed, the gas is pressurized by the air compressor. After the pressure accumulation is completed, the compressed air is released and sent to the nozzle through the air pipe and the material guide pipe to impact the blocked part to achieve the dredging effect. After the pressure accumulation is completed, the compressed air is quickly released and sent to the nozzle through the air pipe and the material guide pipe to directly impact the blocked part. If the first dredging fails, the vent valve is closed, and the pressure accumulation is restarted for the second dredging. This process is repeated until the blockage is completely cleared to ensure that the compressed air can effectively impact the blockage. The use of compressed gas to remove blockages is a non-contact method and will not be affected by the high temperature of the nozzle. The use of compressed air to remove blockages does not consume materials and reduces costs. The work can be repeated many times to fully remove blockages. There is no need to remove the nozzle when removing blockages, making removal more convenient and less cumbersome. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a three-dimensional structural schematic diagram of a 3D printed nozzle blockage detection and dredging device of the present invention;

[0020] Figure 2 It is a three-dimensional structural schematic diagram of another angle of a 3D printed nozzle blockage detection and dredging device of the present invention;

[0021] Figure 3 It is a three-dimensional structural schematic diagram of another angle of a 3D printed nozzle blockage detection and dredging device of the present invention;

[0022] Figure 4 It is a three-dimensional structural schematic diagram of another angle of a 3D printed nozzle blockage detection and dredging device of the present invention;

[0023] Figure 5 for Figure 3 A magnified view of part A in FIG.

[0024] Figure 6 A schematic diagram of the nozzle structure of a 3D printed nozzle blockage detection and dredging device of the present invention;

[0025] Figure 7 It is a schematic diagram of the structure inside the cylinder of a 3D printed nozzle blockage detection and dredging device of the present invention;

[0026] Figure 8 A schematic diagram of the structure of a 3D printed nozzle blockage detection and dredging device for displaying the interior of a sealing valve body of the present invention;

[0027] Fig. 9 It is a structural schematic diagram of a 3D printing nozzle clogging detection system of the present invention;

[0028] Fig.10 It is a schematic diagram of the connection structure of the electromagnet, the electromagnet core and the electromagnet fixing block in a 3D printed nozzle blockage detection and dredging device of the present invention;

[0029] Fig.11 It is a schematic diagram of the connection structure of the output guide plate in a 3D printed nozzle blockage detection and dredging device of the present invention;

[0030] In the figure: 1-nozzle; 2-material guide pipe; 3-extruder; 4-air pipe; 5-air compressor; 6-air release valve body; 7-sealing valve body; 8-compressed air bottle; 9-cylinder; 10-motor; 11-first driving gear; 12-first driven gear; 13-crankshaft; 14-crankshaft connecting rod; 15-barometer; 16-bracket; 17-crankshaft pin; 18-shaft; 19-heat sink; 20-heating block; 21-force push rod; 22-spring; 23-pressing arm ; 24-stepping motor; 25-motor bracket; 26-second driving gear; 27-second driven gear; 28-base plate; 29-electromagnet; 30-electromagnet core; 31-electromagnet fixing block; 32-piston; 33-piston pin; 34-pressure gauge pointer; 35-input end guide block; 36-output end guide block; 37-output guide plate; 38-sealing valve; 39-detection module; 40-extrusion wheel; 41-external groove bearing; 42-input guide plate. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] Example 1: Combination Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 and Figure 8A method for detecting and unblocking nozzle blockage in 3D printing is shown, comprising a nozzle 1, a material guide tube 2, an extruder 3, an air pipe 4, and an air compressor 5. The nozzle 1 is connected to a material guide tube 2, and the material guide tube 2 is connected to an extruder 3. One end of the extruder 3 is connected to the air compressor 5 through the air pipe 4. The gas is pressurized by the air compressor 5. After the pressure accumulation is completed, the compressed air is released and sent into the nozzle 1 through the material guide tube 2 to impact the blocked part for unblocking. A heating block 20 is sleeved on the top of the nozzle 1 for heating the nozzle 1. The 3D printing consumables inside the nozzle 1 are fully heated and melted by heat conduction and then discharged through the filament output process.

[0033] In this embodiment, combined with Figure 1 and Figure 2As shown, the air compressor 5 includes a deflation valve body 6, a sealing valve body 7, a compressed air bottle 8, a cylinder 9, and a motor 10. The deflation valve body 6 is arranged on the air pipe 4 near the extruder 3, and the sealing valve body 7 is arranged on the guide pipe 2 between the extruder 3 and the nozzle 1. The cylinder 9 is connected to one end of the air pipe 4, and a pressure gauge 15 is provided on the cylinder 9. A rotating pressure gauge pointer 34 is provided in the pressure gauge 15. One end of the air pipe 4 is also connected to the cylinder 9. The cylinder 9 is connected to the motor 10 through a transmission mechanism. The transmission mechanism includes a first driving gear 11, a first driven gear 12, a crankshaft 13, a motor 10, a crankshaft connecting rod 14, a bracket 16, a piston 32, a crank pin 17 and a shaft; the motor 10 is arranged below the bracket 16, and the motor 1 0, the output end passes through the bracket 16 and is connected to the first driving gear 11, the first driving gear 11 is connected to the first driven gear 12 by meshing, the diameter of the first driven gear 12 is larger than the diameter of the first driving gear 11, the center of the first driven gear 12 is connected to the shaft 18, the outer sleeve of the shaft 18 is provided with a crankshaft 13, the lower part of the crankshaft 13 is fan-shaped, the upper part of the crankshaft 13 is convex, the lower fan-shaped part of the crankshaft 13 plays a counterweight role, and has the effect of balancing the force and running smoothly, the convex part is connected to the crank pin 17, the crank pin 17 is connected to the crank connecting rod 14, one end of the crank connecting rod 14 is provided with a through hole, a piston pin 33 is provided in the through hole, and the piston pin 33 and the upper part of the crank connecting rod 14 are provided in the piston 32. The air pipe 4 is in a "cross" shape as a whole. The size of the air compression bottle 8 is 10L-50L. The top air port of the air compression bottle 8 is connected to the cylinder 9 through the air pipe 4. In the air compressor 5, after the motor 10 is started, the crankshaft 13 is driven to rotate through the transmission action of the second driving gear 26 and the second driven gear 27, and the crankshaft connecting rod 14 drives the piston 32 to reciprocate in the cylinder 9. After the air in the cylinder 9 is compressed, the pressure increases. When the pressure reaches a certain value, the compressed air enters the air compression bottle 8 through the air pipe 4. In this way, the air compressor 5 works repeatedly and continuously delivers compressed air to the air compression bottle 8 until the pressure in the air compression bottle 8 reaches a certain value and then stops working. The air compression bottle 8 releases the compressed air, and the gas enters the air pipe 4 to act on the nozzle 1.

[0034] A heat sink 19 is disposed above the heating block 20. Figure 6 As shown, the heat sink 19 is sleeved on the nozzle 1 to dissipate the heat generated by the nozzle 1 during operation. Figure 6As shown, the heat sink 19 is not in contact with the top of the heating block 20 and is not tightly connected. When working for a long time, a large amount of heat will accumulate at the nozzle 1. The excess heat generated at the nozzle and to be transferred upward will be dissipated through the heat sink 19 to prevent the upward heat from having an adverse effect on the upper parts. The function of the heating block 20 is to heat the wire and there is no conflict with the heat sink.

[0035] Combination Figure 3 , Figure 5 , Figure 8 and Fig.11 As shown, the extruder 3 includes a stepper motor 24, a booster push rod 21, a spring 22, a pressure arm 23, a second driving gear 26, and a second driven gear 27. One end of the booster push rod 21 is sleeved with a spring 22, and the spring 22 contacts the side wall of the pressure arm 23. An outer groove bearing 41 is provided on the pressure arm 23. The elastic force of the spring 22 is controlled by adjusting the booster push rod 21, thereby adjusting the pressure between the outer groove bearing 41 and the extrusion wheel 40, thereby realizing the control of the extrusion force.

[0036] The output end of the stepper motor 24 is connected to the second driving gear 26, and the second driving gear 26 is connected to the second driven gear 27 by meshing. The output end of the second driven gear 27 is connected to the extrusion wheel 40, and an output guide plate 37 is provided obliquely below the extrusion wheel 40, and an input guide plate 42 is provided above the non-contacting upper portion of the output guide plate 37. An outer groove bearing 41 and the extrusion wheel 40 are provided between the input guide plate 42 and the output guide plate 37, and an output guide plate 37 is provided below the non-contacting middle position of the outer groove bearing 41 and the extrusion wheel 40. After passing through the input guide plate 42, the wire is transmitted between the outer groove bearing 41 and the extrusion wheel 40. The stepper motor 24 works, and the extrusion wheel 40 is driven to rotate by the transmission of the first driving gear 11 and the first driven gear 12. The friction force generated between the extrusion wheel 40 and the wire drives the wire to move downward to the output guide plate 37 at a certain speed by the rotation of the extrusion wheel 40.

[0037] An output end guide block 36 is provided below the output guide plate 37, a sealing valve body 7 is provided below the output end guide block 36, an input end guide block 35 is provided above the sealing valve body 7, an output end guide block 36 is provided below the input end guide block 35, a semi-cylindrical groove is provided at the bottom of the input end guide block 35, a sealing valve 38 is provided in the semi-cylindrical groove, and the diameter of the sealing valve 38 is the same as the diameter of the semi-cylindrical groove, see Fig.10As shown, the sealing valve 38 is connected with an electromagnet core 30, and an electromagnet 29 is arranged outside the electromagnet core 30, and the electromagnet 29 is fixed on the electromagnet fixing block 31. In this embodiment, the stepper motor 24 rotates, and the output end of the stepper motor 24 drives the second driving gear 26 to rotate, and the second driving gear 26 drives the second driven gear 27 meshing therewith to rotate. When the second driven gear 27 rotates, the output end guide block 36 connected thereto transmits the 3D printing consumables to the sealing valve body 7 through the output guide plate 37. When the sealing valve body 7 is opened, the 3D printing consumables enter the guide pipe 2 through the input end guide block 35 and the output end guide block 36 in sequence.

[0038] In this embodiment, the stepper motor 24 is installed on the motor bracket 25, and the motor bracket 25 is connected to the substrate 28. The stepper motor 24 is installed in a fixed position through the motor bracket 25. A sealing valve 38 is provided inside the sealing valve body 7, and the sealing valve 38 is connected to the electromagnet 29. The sealing valve body 7 is controlled by the electromagnet 29, so that when the printer is working normally, the consumables can pass through the sealing valve body 7 normally, and when unblocking work is required, the air path is sealed so that the compressed air can fully impact the blocked part of the nozzle 1.

[0039] Example 2: See Fig. 9 As shown, the detection system for nozzle blockage of 3D printing includes a detection module 39 and a nozzle blockage detection and unblocking device for 3D printing as described in any of the above items. The detection module 39 is arranged on the guide tube 2 to detect the speed of the wire. The detection module 39 includes an optical sensor, an optical comparison sensor and a voltage comparator. The optical sensor is electrically connected to the single-chip microcomputer. The optical sensor collects the movement of the wire, converts the movement of the wire into a digital quantity and sends it to the single-chip microcomputer for processing and recording. The optical comparison sensor is supplemented by a voltage comparator. When the wire passes through the channel normally, the optical comparison sensor is cut off. When the wire leaves the channel, the optical comparison sensor is turned on, and the single-chip microcomputer controls the stepper motor 24 to stop moving. In this embodiment, the optical comparison sensor is arranged above the input guide block, and the optical sensor ADNS-2030 is responsible for collecting the movement of the wire, converting the movement of the wire into a digital quantity and sending it to the single-chip microcomputer for processing and recording. An optical beam sensor ITR9608 is set at the end of the sensor, and a voltage comparator LM393N is used to realize that the sensor is cut off when the wire passes through the channel normally, and the sensor is turned on when the wire leaves the channel, and the single-chip microcomputer controls the stepper motor 24 to stop moving. This embodiment mainly determines whether the nozzle 1 has a wire blockage phenomenon by continuously monitoring the current of the stepper motor 24. After confirming that the wire blockage has occurred, the nozzle 1 is heated to a high temperature state of 250°C. This temperature is set according to the melting point of most 3D printing consumables to ensure that the consumables can be fully melted to prepare for the subsequent unblocking operation.

[0040] See also Figure 1 As shown, the barometer 15 is provided with a rotatable barometer pointer 34 for monitoring the pressure in the compressed gas bottle.

[0041] The specific working process of the present invention is as follows: before unblocking the nozzle 1, the nozzle 1 is heated to 250°C by the heating block 20, and the consumables are withdrawn through the externally connected wire feeder to leave a compressed air channel, and the air compressor 5 is started to store pressure in the gas cylinder. At this time, the sealing valve body 7 is opened, and the material guide pipe 2 is closed. The pressure accumulation is judged according to the pressure value displayed by the barometer 15. When the pressure accumulation is completed, the sealing valve body 7 is closed, and the air release valve body 6 is opened to release the compressed air. The compressed air acts on the nozzle 1 along the material guide pipe 2 to achieve the unblocking effect. Figure 8 As shown, after opening the vent valve body 6, the compressed air is released to detect the pressure in the compressed air bottle 8 according to the barometer 15. If the pressure continues to rise, the dredging fails, and then the vent valve body 6 is closed, and the pressure is accumulated again for the second dredging until the blockage is cleared. The air compressor 5 includes the vent valve body 6, the sealing valve body 7, the compressed air bottle 8, the cylinder 9, the motor 10, etc. When the dredging work is needed, the gas is pressurized by the air compressor 5. After the pressure accumulation is completed, the compressed air is released, and the compressed air is sent to the nozzle 1 through the air pipe 4 and the guide pipe 2 to impact the blocked part to achieve the dredging effect. After the pressure accumulation is completed, the compressed air is quickly released, and the compressed air is sent to the nozzle 1 through the air pipe 4 and the guide pipe 2 to directly impact the blocked part. If the first dredging fails, the vent valve is closed, and the pressure is accumulated again for the second dredging. Repeat this process until the blockage is completely cleared. After releasing the compressed air, the pipeline pressure is immediately detected. If the pressure drops rapidly and remains stable, it means that the dredging is successful; if the pressure continues to rise, it indicates that the dredging has failed. This operation needs to be quick and accurate to ensure that the compressed air can effectively impact the blockage. After the unblocking is successful, the nozzle 1 needs to be further inspected and cleaned to ensure that there is no residual blockage inside the nozzle 1 to avoid affecting the subsequent printing quality. The experience and lessons of this unblocking should be recorded, the cause of the wire blockage should be analyzed, and corresponding preventive measures should be taken to reduce the possibility of wire blockage in the future. The present invention controls the sealing valve body 7 through the electromagnet 29, so that when the printer is working normally, the consumables can pass through the sealing valve body 7 normally, and when the unblocking work is required, the air path is sealed so that the compressed air can fully impact the blocked part of the nozzle 1.

[0042] When judging whether the nozzle 1 is blocked, the reference basis is to detect the current of the wire feeding motor 10 on the equipment platform of the existing printer, collect current data through real-time monitoring, design different wire blocking experiments, and let the print head go from unblocked to blocked during normal operation. Conduct multiple experiments to obtain the relatively stable change law of the current, and then obtain the critical current value to support the wire blocking prediction.

[0043] Example 3: When performing 3D printing, wire blockage in the nozzle 1 is a common problem, especially when using high-viscosity materials or after long-term printing. This embodiment mainly detects whether the nozzle 1 is blocked. This embodiment uses the current change trend to predict wire blockage. On the equipment platform of the existing printer, the current of the wire feeding motor 10 is detected, and the current data is collected in real time using an AD converter. By designing different wire blockage experiments, the print head is allowed to go from unblocked to blocked during normal operation, and multiple experiments are performed to obtain a relatively stable change law of the current. The critical current value of the wire-exiting process, i.e., the critical minimum current and the critical maximum current, is obtained. The critical minimum current is used to predict the occurrence of wire blockage, and the critical maximum current is used to determine whether wire blockage has occurred. In summary, the work of predicting whether wire blockage is about to occur and determining whether wire blockage has occurred by the current change trend is completed.

[0044] Taking polylactic acid (PLA) material as an example, first query the data to determine the change in rigidity of the material as the temperature changes, and then perform temperature field simulation to determine the softening degree and rigidity change law of the wire at different temperatures, so as to determine the critical temperature value. The printing temperature range of polylactic acid (PLA) is from 180 to 230 degrees Celsius, that is, the critical minimum temperature and the critical maximum temperature. At the same time, the most suitable temperature is determined while maintaining heat input. In this embodiment, the optimal setting printing temperature of polylactic acid (PLA) is 215 degrees Celsius. A sensor is arranged at a certain place, and the temperature of the wire inlet is measured by a temperature gun. When the temperature of the wire inlet reaches a certain value, the temperature sensor determines the upper limit value. The critical minimum temperature is used to predict the occurrence of wire blockage, and the critical maximum temperature is used to determine whether the wire blockage has occurred. In summary, the work of predicting whether the wire is about to be blocked and judging whether the wire blockage has occurred is completed by the temperature change trend. When dredging work is required, the gas is pressurized by the compressor. When the pressure accumulation is completed, the compressed air is released, and the compressed air is sent to the nozzle 1 through the guide pipe 2 to impact the blocked part to achieve the dredging effect.

[0045] Embodiment 3, considering that the initial wire feeding process should ensure the stiffness and toughness of the wire, in order to prevent its temperature from being too high, this embodiment adds a fan cooling device at the wire inlet.

[0046] The basic principles and main features of the present invention are described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for illustrating the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which shall fall within the scope of the present invention to be protected. The scope of protection of the invention shall be defined by the attached claims and their equivalents.

Claims

1. A method for detecting and clearing blockage of a nozzle for 3D printing, comprising a nozzle (1), a wire feeder, a material guide tube (2), an extruder (3), an air pipe (4), and an air compressor (5), wherein the nozzle (1) is connected to the material guide tube (2) above, the material guide tube (2) is connected to the extruder (3) above, one end of the extruder (3) is connected to the air compressor (5) via the air pipe (4), and a heating block (20) is sleeved above the nozzle (1) for heating the nozzle (1); The air compressor (5) comprises a deflation valve body (6), a sealing valve body (7), a compressed air bottle (8), a cylinder (9), and a motor (10); the deflation valve body (6) is arranged on the air pipe (4) at a position close to the extruder (3); the sealing valve body (7) is arranged on the material guide pipe (2) between the extruder (3) and the nozzle (1); a pressure gauge (15) is arranged on the cylinder (9); a rotating pressure gauge pointer (34) is arranged in the pressure gauge (15); one end of the air pipe (4) is also connected to the cylinder (9); and the cylinder (9) is connected to the motor (10) via a transmission mechanism; The extruder (3) comprises a stepper motor (24), a booster push rod (21), a spring (22), a pressure arm (23), a second driving gear (26), and a second driven gear (27); the output end of the stepper motor (24) is connected to the second driving gear (26); the second driving gear (26) is connected to the second driven gear (27) in a meshing manner; the output end of the second driven gear (27) is connected to an extrusion wheel (40); an output guide plate (37) is provided obliquely below the extrusion wheel (40); an input end guide block (35) is provided below the output guide plate (37); and a sealing valve body (7) is provided below the input end guide block (35); By continuously monitoring the current of the stepper motor (24), it is determined whether the nozzle (1) has a wire blockage phenomenon. After confirming that the wire blockage has occurred, the nozzle (1) is heated to a high temperature of 250°C, and the consumables are withdrawn through an externally connected wire feeder to leave a compressed air channel. At the same time, the air compressor (5) is started to accumulate pressure in the gas cylinder. At this time, the sealing valve body (7) is opened, and the material guide pipe (2) is closed. The pressure accumulation situation is determined based on the pressure value displayed on the pressure gauge (15). When the pressure accumulation is completed, the sealing valve body (7) is closed, and the vent valve body (6) is opened to release the compressed air. The compressed air acts on the nozzle (1) along the material guide pipe (2) to clear the blockage.

2. A method for detecting and unblocking nozzle blockage in 3D printing according to claim 1, characterized in that: A heat sink (19) is provided above the heating block (20); the heat sink (19) is sleeved on the nozzle (1) and is used to dissipate heat generated by the nozzle (1) during operation.

3. A method for detecting and unblocking nozzle blockage in 3D printing according to claim 1, characterized in that: A semi-cylindrical groove is provided at the bottom of the input end guide block (35), a sealing valve (38) is provided in the semi-cylindrical groove, the diameter of the sealing valve (38) is the same as the diameter of the semi-cylindrical groove, the sealing valve (38) is connected to an electromagnet core (30), an electromagnet (29) is provided outside the electromagnet core (30), and the electromagnet (29) is fixed on the electromagnet fixing block (31).

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