Automatic connection feeding device of 3D printer

Abstract

This invention discloses an automatic filament feeding device for a 3D printer, comprising a filament hopper, a filament conveying mechanism, a cutting unit, a first filament outlet pipe, a second filament outlet pipe, a traversing assembly, and a filament outlet die. The filament conveying mechanism includes a fixed base, a first filament extrusion unit, and a second filament extrusion unit. Through the filament conveying mechanism, the cutting unit, and the traversing assembly, automatic splicing of two filament rolls for printing is achieved, solving the problem of existing industrial-grade printers pausing printing due to insufficient material, requiring manual material replacement to continue printing. This results in high printing efficiency. The fast splicing speed of the two filament rolls avoids printing pauses caused by insufficient filament on a single roll, preventing the printed model from cooling and shrinking. Furthermore, it avoids gaps between the extruded filament and the already printed model surface after filament roll replacement, ensuring the mechanical properties and surface accuracy of the printed model, reducing the scrap rate, and avoiding filament waste.

Description

Technical Field

[0001] This invention relates to the field of 3D printing technology, and in particular to an automatic feeding device for a 3D printer. Background Technology

[0002] The filament supply system is a crucial component of industrial-grade 3D printers, primarily consisting of the filament hopper and the feed motor. Feeding methods are generally divided into short-range and long-range feeding. The difference lies in the feeding mechanism: short-range feeding involves mounting a stepper motor directly on the nozzle moving unit, feeding the filament to the high-temperature nozzle at close range; while long-range feeding involves mounting the stepper motor on the 3D printer body, remotely guiding the filament into the nozzle. Most industrial-grade printers employ long-range feeding. Compared to short-range feeding, this method reduces the load on the nozzle moving unit, decreases its inertia, improves its positioning accuracy, and increases the overlap of material trajectories between layers, thus effectively improving 3D printing precision. Furthermore, the lighter weight of the nozzle moving unit allows for increased printing speed while maintaining accuracy, better ensuring the forming precision and quality of the 3D printed parts.

[0003] Currently, many printers using remote feeding methods typically have a filament box on the side of the machine body. This box houses a stepper motor and a single filament spool. The filament is pulled by the motor through a feeding hose to the printhead moving unit, where it is then heated and extruded into print. Considering that industrial printers are often used to print large models, which require a large amount of filament, a single roll of filament may sometimes be insufficient to complete the printing task in one go. During printing, the printer must wait for the filament depletion detection module to detect the material running out and immediately pause operation. The printer then resumes operation only after a second roll of filament is manually replaced. This method reduces printer efficiency, prolongs the printing time for a single model, and requires manual monitoring of the printing status.

[0004] To address the issue of insufficient filament supply per roll, existing technologies either employ a multi-head design, where multiple printheads are installed on the moving unit, each connected to a roll of filament. The advantage of this design is that multiple printheads can print alternately; when one roll runs out, another roll can continue printing, avoiding pauses during printing and enabling the printing of multi-color models. Alternatively, a merging device is installed on the moving unit. This device has two filament inlets at the top, each connected to a remote filament via a flexible hose, and a high-temperature printhead at the bottom. Its function is to allow two rolls of filament to enter one printhead, but only one roll is used for printing at a time. When one roll runs out, the merging device switches to another roll. While both methods allow for instant roll changing and reduce changeover time, both multi-head and merging device designs have significant drawbacks: they increase the mass of the printhead moving unit, affecting printing accuracy and speed. Summary of the Invention

[0005] The purpose of this invention is to provide an automatic feeding device for 3D printers to solve one or more technical problems existing in the background art.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] An automatic feeding device for a 3D printer includes a filament hopper, a filament conveying mechanism, a cutting unit, a first filament outlet pipe, a second filament outlet pipe, a transverse component, and a filament outlet die head; the filament hopper is provided with a first roll holder and a second roll holder for mounting filament rolls;

[0008] The filament conveying mechanism includes a fixed base and a first filament extrusion unit and a second filament extrusion unit symmetrically arranged on the fixed base. The fixed base is located on one side of the filament hopper. The input ends of the first filament extrusion unit and the second filament extrusion unit are both connected to the filament hopper. The beginning ends of the first filament outlet pipe and the second filament outlet pipe are respectively connected to the output ends of the first filament extrusion unit and the second filament extrusion unit.

[0009] The ends of the first and second wire-exiting pipes are fixed to one side of the wire-exiting die head. The lateral movement assembly is used to drive the wire-exiting die head to move left and right between the first and second wire-exiting pipes. The cutting unit is located on one side of the wire-exiting die head.

[0010] When the lateral movement assembly drives the input end of the filament extrusion die to connect with the end of the first filament extrusion pipe, the first filament extrusion unit extrudes the filament from the filament roll on the first spool through the first filament extrusion pipe into the filament extrusion die. When there is a shortage of filament on the filament roll on the first spool, the first filament extrusion unit stops operating, the cutting unit cuts the filament in the filament extrusion die, the lateral movement assembly drives the filament extrusion die to move to the second filament extrusion pipe and connects the filament extrusion die with the end of the second filament extrusion pipe, and the second filament extrusion unit extrudes the filament from the filament roll on the second spool through the second filament channel into the filament extrusion die.

[0011] Preferably, the first filament extrusion unit includes a feeding motor, an extrusion wheel, an extrusion pulley, a guide head, and an outlet head. The fixed base has an installation cavity. The feeding motor is located at the bottom of the fixed base, and the shaft end of the feeding motor extends into the installation cavity. The extrusion wheel is located at the shaft end of the feeding motor. The extrusion pulley is slidably disposed on one side of the extrusion wheel. The guide head and the outlet head are located on both sides of the installation cavity. The line connecting the guide head and the outlet head coincides with the gap between the extrusion wheel and the extrusion pulley.

[0012] Preferably, the first filament extrusion unit further includes a sliding pusher and a locking component. The sliding pusher is slidably engaged with the mounting cavity. The extrusion pulley is disposed on the sliding pusher. The locking component is disposed at one end of the sliding pusher. The other end of the sliding pusher is provided with a top rod extending out of the fixed seat. The locking component is used to lock or unlock the sliding pusher.

[0013] Preferably, the locking assembly includes a limiting block, a hook, and a return spring. The limiting block has a limiting groove, and the mounting cavity is provided with a positioning platform. One end of the hook is hinged to the positioning platform, and the other end of the hook is provided with a limiting pin. The limiting pin is located in the limiting groove. The two ends of the return spring abut against the limiting block and the positioning platform, respectively. The limiting groove is provided with a first limiting part and a second limiting part. When the limiting pin abuts against the first limiting part, the distance between the extrusion pulley and the extrusion wheel is less than the diameter of the guide wire head. When the limiting pin abuts against the second limiting part, the distance between the extrusion pulley and the extrusion wheel is greater than the diameter of the guide wire head.

[0014] Preferably, the limiting groove is provided with a protrusion, and the inner side of the limiting groove and the outer side of the protrusion form a first limiting part, a first self-locking channel, a second limiting part and a second self-locking channel that are connected in a counterclockwise sequence. The first limiting part is located on the inner wall of the limiting groove near the positioning platform.

[0015] Preferably, the locking assembly further includes a torsion spring, which is sleeved on the hinge shaft between the hook and the positioning platform. One end of the torsion spring abuts against the hook, and the other end of the torsion spring is fixed to the positioning platform.

[0016] Preferably, the first filament extrusion unit further includes a material breakage sensor, which is disposed on the fixed base and the detection end of the material breakage sensor is disposed inside the filament guide head.

[0017] Preferably, the transverse component includes a slide rail stepper motor and a slider, the wire ejection die is disposed on the slider, and the slider is disposed at the movable end of the slide rail stepper motor.

[0018] Preferably, the cutting unit includes a push rod motor, a cutting blade, and a cutting die. The push rod motor is vertically mounted on the slider, the cutting blade is located at the movable end of the push rod motor, and the cutting die is located inside the wire-exiting die head. The push rod motor is used to drive the cutting blade to close and separate from the cutting die.

[0019] The beneficial effects of this invention are as follows: Through the filament conveying mechanism, cutting unit, and traversing assembly, automatic connection and printing of two filament rolls is achieved, solving the problem of existing industrial printers pausing printing due to insufficient material, requiring manual material replacement to resume printing. This results in high printing efficiency. The fast connection speed between the two filament rolls avoids printing pauses caused by insufficient filament on a single roll, preventing the printed model from cooling and shrinking. Furthermore, it avoids gaps between the extruded filament and the already printed model surface after filament roll replacement, ensuring the mechanical properties and surface accuracy of the printed model, reducing the scrap rate, and preventing filament waste. Attached Figure Description

[0020] The accompanying drawings further illustrate the present invention, but the content of the drawings does not constitute any limitation on the present invention.

[0021] Figure 1 This is a schematic diagram of the overall structure of one embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram of the structure of a wire conveying mechanism according to one embodiment of the present invention;

[0023] Figure 3 This is a schematic diagram of the structure of the first filament extrusion unit according to one embodiment of the present invention;

[0024] Figure 4 yes Figure 3 A magnified view of part A;

[0025] Figure 5 This is a schematic diagram of the structure of a transverse moving component according to one embodiment of the present invention;

[0026] Figure 6 This is a schematic diagram of the internal structure of the wire-exiting die head according to one embodiment of the present invention.

[0027] The components include: filament hopper 1, first filament outlet pipe 41, second filament outlet pipe 42, transverse component 5, filament outlet die head 6, filament roll 111, first roll frame 11, fixed base 21, first filament extrusion unit 22, second filament extrusion unit 23, feeding motor 221, extrusion wheel 222, extrusion pulley 223, filament guide head 224, filament outlet head 225, mounting cavity 211, sliding push block 24, push rod 226, limiting block 25, hook 227, return spring 228, limiting groove 251, positioning platform 26, limiting pin 229, first limiting part 252, second limiting part 253, protrusion 27, first self-locking channel 254, second self-locking channel 255, material breakage sensor 28, slide rail stepper motor 51, slider 52, push rod motor 31, cutting blade 32, and cutting die 33. Implementation

[0028] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0029] This embodiment describes an automatic feeding device for a 3D printer, as shown in the attached diagram. Figure 1 It includes a filament bin 1, a filament conveying mechanism, a cutting unit, a first filament outlet pipe 41, a second filament outlet pipe 42, a transverse moving assembly 5, and a filament outlet die head 6; the filament bin 1 is provided with a first roll frame 11 and a second roll frame for installing filament rolls 111.

[0030] The filament conveying mechanism includes a fixed base 21 and a first filament extrusion unit 22 and a second filament extrusion unit 23 symmetrically arranged on the fixed base 21. The fixed base 21 is located on one side of the filament hopper 1. The input ends of the first filament extrusion unit 22 and the second filament extrusion unit 23 are both connected to the filament hopper 1. The beginning ends of the first filament outlet pipe 41 and the second filament outlet pipe 42 are respectively connected to the output ends of the first filament extrusion unit 22 and the second filament extrusion unit 23.

[0031] The ends of the first wire-exiting pipe 41 and the second wire-exiting pipe 42 are fixed to one side of the wire-exiting die head 6. The transverse moving component 5 is used to drive the wire-exiting die head 6 to move left and right between the first wire-exiting pipe 41 and the second wire-exiting pipe 42. The cutting unit is located on one side of the wire-exiting die head 6.

[0032] When the transverse component 5 drives the input end of the filament extrusion die 6 to connect with the end of the first filament extrusion pipe 41, the first filament extrusion unit 22 extrudes the filament from the filament roll 111 on the first spool 11 through the first filament extrusion pipe 41 into the filament extrusion die 6. When the filament roll 111 on the first spool 11 is short of material, the first filament extrusion unit 22 stops operating, the cutting unit cuts the filament in the filament extrusion die 6, the transverse component 5 drives the filament extrusion die 6 to move to the second filament extrusion pipe 42 and connects the filament extrusion die 6 with the end of the second filament extrusion pipe 42, and the second filament extrusion unit 23 extrudes the filament from the filament roll 111 on the second spool 11 through the second filament channel into the filament extrusion die 6.

[0033] The filaments on two filament rolls 111 are conveyed separately by a filament conveying mechanism, and the excess filament is cut off by a cutting unit. The filament exit head 6 moves between the first filament exit pipe 41 and the second filament exit pipe 42 via a transverse component 5. This achieves automatic printing by connecting the two filament rolls 111 together, solving the problem of insufficient material in existing industrial printers causing print jobs to pause and requiring manual material replacement to continue printing. This results in high printing efficiency. The fast connection speed of the two filament rolls 111 avoids print pauses due to insufficient filament in a single roll, preventing the printed model from cooling and shrinking. This also avoids gaps between the extruded filament and the already printed model surface after filament roll 111 replacement, ensuring the mechanical properties and surface accuracy of the printed model, reducing the scrap rate, and avoiding filament waste.

[0034] Preferred options are listed in the appendix. Figure 2-4The first filament extrusion unit 22 includes a feeding motor 221, an extrusion wheel 222, an extrusion pulley 223, a guide head 224, and an outlet head 225. The guide head 224 and the outlet head 225 are respectively used to connect to the filament hopper 1 and the beginning of the first filament outlet pipe 41. A mounting cavity 211 is provided on the fixed base 21. The feeding motor 221 is located at the bottom of the fixed base 21, and the shaft end of the feeding motor 221 extends into the mounting cavity 211. The extrusion wheel 222 is located at the shaft end of the feeding motor 221. The extrusion pulley 223 is slidably arranged on one side of the extrusion wheel 222. The guide head 224 and the outlet head 225 are located on both sides of the mounting cavity 211. The line connecting the guide head 224 and the outlet head 225 coincides with the gap between the extrusion wheel 222 and the extrusion pulley 223. When the first filament extrusion unit 22 extrudes the filament, the extrusion wheel 222 is driven to rotate forward by the feeding motor 221. This causes the filament located between the extrusion wheel 222 and the extrusion pulley 223 to be gradually extruded from between them to the filament exit head 225 under the action of friction. The filament then passes sequentially through the first filament exit pipe 41 and the filament exit die head 6, and is pulled onto the filament roll 111 through the guide head 224 into the mounting cavity 211. This achieves the extrusion of the filament by the first filament extrusion unit 22. When the cutting unit cuts the filament in the filament exit die head 6, leaving residual material in the first filament exit pipe 41, the feeding motor 221 drives the extrusion wheel 222 to rotate in reverse. This causes the residual material in the first filament exit pipe 41 to gradually retreat back into the filament bin 1 under the action of friction, facilitating the cleaning of the residual material.

[0035] Furthermore, the first filament extrusion unit 22 also includes a sliding pusher 24 and a locking assembly. The sliding pusher 24 is slidably engaged with the mounting cavity 211. The extrusion pulley 223 is provided on the sliding pusher 24. The locking assembly is provided at one end of the sliding pusher 24. The other end of the sliding pusher 24 is provided with a top rod 226 extending out of the fixed seat 21. The locking assembly is used to lock or unlock the sliding pusher 24.

[0036] The sliding pusher 24 slides into the mounting cavity 211, thereby driving the extrusion pulley 223 to move closer to or further away from the extrusion wheel 222. A push rod 226 is provided at the other end of the sliding pusher 24, allowing the operator to push the sliding pusher 24 from outside the positioning table 26 via the push rod 226. This adjusts the distance between the extrusion pulley 223 and the extrusion wheel 222, facilitating the installation of the filament roll 111 by allowing the filament at the head of the roll to pass between the extrusion pulley 223 and the extrusion wheel 222. After the filament enters between the extrusion pulley 223 and the extrusion wheel 222, pushing the push rod 226 again completes the installation of the filament roll 111. A locking assembly is used to lock or unlock the position of the sliding pusher 24, ensuring that each push of the push rod 226 moves the extrusion pulley 223 to a position closer to or further away from the extrusion wheel 222 and locks it in that position. This allows for adjustment of the clamping or separation of the filament by the extrusion pulley 223 and the extrusion wheel 222.

[0037] Furthermore, the locking assembly includes a limiting block 25, a hook 227, and a return spring 228. The limiting block 25 has a limiting groove 251, and the mounting cavity 211 is provided with a positioning platform 26. One end of the hook 227 is hinged to the positioning platform 26, and the other end of the hook 227 is provided with a limiting pin 229. The limiting pin 229 is located in the limiting groove 251, and the two ends of the return spring 228 abut against the limiting block 25 and the positioning platform 26, respectively.

[0038] By creating a limiting groove 251 on the limiting block 25 that mates with the limiting pin 229 of the hook 227, and by hinged one end of the hook 227 to the positioning table 26, the movement of the hook 227 is limited. The swinging of the hook 227 also limits the movement of the sliding push block 24. A return spring 228 is located between the limiting block 25 and the positioning table 26 to provide a restoring force for the sliding push block 24.

[0039] The limiting groove 251 is provided with a first limiting part 252 and a second limiting part 253. When the limiting pin 229 abuts against the first limiting part 252, the distance between the extrusion pulley 223 and the extrusion wheel 222 is less than the diameter of the guide head 224. At this time, the filament between the extrusion pulley 223 and the extrusion wheel 222 is clamped. At this time, the rotation of the extrusion wheel 222 can realize the extrusion or retraction of the filament. When the limiting pin 229 abuts against the second limiting part 253, the distance between the extrusion pulley 223 and the extrusion wheel 222 is greater than the diameter of the guide head 224. At this time, the extrusion pulley 223 and the extrusion wheel 222 are separated. When changing the filament roll 111, the operator can manually insert the head of the filament between the extrusion pulley 223 and the extrusion wheel 222, which facilitates the operation of changing the filament roll 111.

[0040] Furthermore, a protrusion 27 is provided within the limiting groove 251. A first limiting part 252, a first self-locking channel 254, a second limiting part 253, and a second self-locking channel 255 are formed counterclockwise sequentially between the inner side of the limiting groove 251 and the outer side of the protrusion 27. The first limiting part 252 is located on the inner wall of the limiting groove 251 near the positioning platform 26. The protrusion 27 within the limiting groove 251 creates the first and second self-locking channels 254 and 255, respectively guiding the limiting pin 229 to move to abut against the second limiting part 253 and the first limiting part 252, thereby achieving self-locking of the sliding push block 24.

[0041] Furthermore, the locking assembly also includes a torsion spring, which is sleeved on the hinge shaft between the hook 227 and the positioning table 26. One end of the torsion spring abuts against the hook 227, and the other end of the torsion spring is fixed to the positioning table 26. By setting the torsion spring at one end of the hook 227, when the sliding push block 24 slides relative to the positioning table 26, the other end of the hook 227 maintains a tendency to rebound and reset under the elastic force of the torsion spring. That is, the limiting pin 229 slides tightly against the inner wall of the limiting groove 251, thereby limiting the movement path of the limiting pin 229. When the sliding push block 24 is pushed once, the limiting pin 229 moves under the limitation of the first self-locking channel 254 to abut against the second limiting part 253. When the sliding push block 24 is pushed again, the limiting pin 229 moves under the limitation of the second self-locking channel 255 to abut against the first limiting part 252, thereby locking the movable push block.

[0042] Preferably, the first filament extrusion unit 22 further includes a material breakage sensor 28, which is mounted on the fixed base 21 and has its detection end located inside the filament guide head 224. The material breakage sensor 28 is used to detect whether filament has passed through the filament guide head 224. When the material breakage sensor 28 detects that no filament has passed through, that is, when the filament roll 111 on the first roll holder 11 is short of material, the first filament extrusion unit 22 can be stopped, and then the cutting unit and the second filament extrusion unit 23 can be operated sequentially to achieve the connection of the printing filament.

[0043] In this embodiment, the second filament extrusion unit 23 has the same structure as the first filament extrusion unit 22.

[0044] Preferred options are listed in the appendix. Figure 5 The transverse component 5 includes a slide rail stepper motor 51 and a slider 52. The filament extrusion die 6 is mounted on the slider 52, which is located at the movable end of the slide rail stepper motor 51. By driving the slider 52 to slide through the slide rail stepper motor 51, the filament extrusion die 6 can move between the first filament extrusion channel 41 and the second filament extrusion channel 42, enabling immediate switching to another filament extrusion unit for feeding when filament shortage occurs during printing.

[0045] Preferred options are listed in the appendix. Figure 6 The cutting unit includes a push rod motor 31, a cutting blade 32, and a cutting die 33. The push rod motor 31 is vertically mounted on the slider 52, the cutting blade 32 is located at the movable end of the push rod motor 31, and the cutting die 33 is located inside the wire exiting die head 6. The push rod motor 31 drives the cutting blade 32 and the cutting die 33 to close and separate. By pushing the cutting blade 32 and the cutting die 33 to close, the remaining material inside the wire exiting die head 6 is cut off.

[0046] The working principle of the automatic feeding device for the 3D printer in this embodiment is as follows:

[0047] Hang the two rolls of filament 111 in the first roll holder 11 and the second roll holder inside the filament hopper 1, and press the top rod 226 once each to increase the distance between the extrusion wheel 222 and the extrusion pulley 223, thus opening the filament feeding channel for the two rolls of filament. At this point, you can manually insert the head of the two rolls of filament 111 into the guide head 224 at the filament inlet of the filament hopper 1 until the filament head reaches the end of the first filament outlet pipe 41 or the second filament outlet pipe 42 (you can observe the insertion position through the transparent first filament outlet pipe and the second filament outlet pipe 42). After the filament is inserted into place, press the top rod 226 again to make the extrusion wheel 222 and the extrusion pulley 223 press the filament tightly.

[0048] Printing begins, and the slide rail stepper motor 51 operates, moving the filament extrusion die 6 from the middle position until the input end of the filament extrusion die 6 is aligned with the end of the first filament extrusion pipe 41 or the end of the second filament extrusion pipe 42 and the centers are coaxial. The corresponding filament extrusion unit's feeding motor 221 starts working, so that the filament is gradually extruded into the filament extrusion die 6, and then enters the 3D printer for printing through the output end of the filament extrusion die 6.

[0049] When the material breakage sensor 28 detects that the printing of the filament roll 111 is exhausted, the push rod motor 31 pushes upward to close the cutting blade 32 and the cutting die 33, cutting the filament and then resetting the push rod. Then, the slide rail stepper motor 51 drives the filament extrusion die head 6 to move to another filament extrusion pipe, so that the filament extrusion die head 6 is connected to the end of the other filament extrusion pipe and is coaxial in center. The filament extrusion unit corresponding to the filament extrusion pipe starts working, feeding the filament into the filament extrusion die head 6. The new filament will push the filament left at the front end of the filament extrusion die head 6 after it has been cut into the printer for printing, thus achieving the connection of two filament rolls. During the feeding process of the filament extrusion unit, the feeding motor 221 of the completed filament extrusion unit rotates in the reverse direction, returning the cut filament residue to the filament hopper 1 for easy removal and replacement by the operator.

[0050] If two rolls of material are still insufficient to complete the printing task, the operator only needs to install another roll of filament 111 in the filament hopper 1 before the filament extrusion unit stops feeding. This allows for continued printing of large parts. This achieves unmanned automated printing, reduces the scrap rate of model printing, saves consumables, and ultimately improves the working efficiency of the FDM 3D printer.

[0051] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are merely for explaining the principles of the invention and should not be construed as limiting the scope of protection of the invention in any way. Based on this explanation, those skilled in the art can readily conceive of other specific embodiments of the invention without inventive effort, and these embodiments will all fall within the scope of protection of the present invention.

Claims

1. An automatic feeding device for a 3D printer, characterized in that, It includes a filament hopper, a filament conveying mechanism, a cutting unit, a first filament outlet pipe, a second filament outlet pipe, a transverse moving assembly, and a filament outlet die head; the filament hopper is provided with a first roll frame and a second roll frame for mounting filament rolls; The filament conveying mechanism includes a fixed base and a first filament extrusion unit and a second filament extrusion unit symmetrically arranged on the fixed base. The fixed base is located on one side of the filament hopper. The input ends of the first filament extrusion unit and the second filament extrusion unit are both connected to the filament hopper. The beginning ends of the first filament outlet pipe and the second filament outlet pipe are respectively connected to the output ends of the first filament extrusion unit and the second filament extrusion unit. The ends of the first and second wire-exiting pipes are fixed to one side of the wire-exiting die head. The lateral movement assembly is used to drive the wire-exiting die head to move left and right between the first and second wire-exiting pipes. The cutting unit is located on one side of the wire-exiting die head. When the lateral movement assembly drives the input end of the filament extrusion die to connect with the end of the first filament extrusion pipe, the first filament extrusion unit extrudes the filament from the filament roll on the first spool through the first filament extrusion pipe into the filament extrusion die. When there is a shortage of filament on the filament roll on the first spool, the first filament extrusion unit stops operating, the cutting unit cuts the filament in the filament extrusion die, the lateral movement assembly drives the filament extrusion die to move to the second filament extrusion pipe and connects the filament extrusion die with the end of the second filament extrusion pipe, and the second filament extrusion unit extrudes the filament from the filament roll on the second spool through the second filament channel into the filament extrusion die. The first filament extrusion unit includes a feeding motor, an extrusion wheel, an extrusion pulley, a filament guide head, and a filament outlet head, and the fixed base has an installation cavity. The first filament extrusion unit further includes a sliding push block and a locking component. The sliding push block is slidably engaged with the mounting cavity. The extrusion pulley is disposed on the sliding push block. The locking component is disposed at one end of the sliding push block. The other end of the sliding push block is provided with a top rod extending out of the fixed seat. The locking component is used to lock or unlock the sliding push block. The locking assembly includes a limiting block, a hook, and a return spring. The limiting block has a limiting groove, and the mounting cavity has a positioning platform. One end of the hook is hinged to the positioning platform, and the other end of the hook has a limiting pin. The limiting pin is located in the limiting groove. The two ends of the return spring abut against the limiting block and the positioning platform, respectively. The limiting groove has a first limiting part and a second limiting part. When the limiting pin abuts against the first limiting part, the distance between the extrusion pulley and the extrusion wheel is less than the diameter of the guide wire head. When the limiting pin abuts against the second limiting part, the distance between the extrusion pulley and the extrusion wheel is greater than the diameter of the guide wire head.

2. The automatic feeding device for a 3D printer according to claim 1, characterized in that, The feeding motor is located at the bottom of the fixed base, and the shaft end of the feeding motor extends into the mounting cavity. The extrusion wheel is located at the shaft end of the feeding motor. The extrusion pulley is slidably disposed on one side of the extrusion wheel. The guide head and the output head are located on both sides of the mounting cavity. The line connecting the guide head and the output head coincides with the gap between the extrusion wheel and the extrusion pulley.

3. The automatic feeding device for a 3D printer according to claim 2, characterized in that, The limiting groove is provided with a protrusion, and the inner side of the limiting groove and the outer side of the protrusion form a first limiting part, a first self-locking channel, a second limiting part and a second self-locking channel that are connected in a counterclockwise sequence. The first limiting part is located on the inner wall of the limiting groove near the positioning platform.

4. The automatic feeding device for a 3D printer according to claim 2, characterized in that, The locking assembly also includes a torsion spring, which is sleeved on the hinge shaft between the hook and the positioning platform. One end of the torsion spring abuts against the hook, and the other end of the torsion spring is fixed to the positioning platform.

5. The automatic feeding device for a 3D printer according to claim 1, characterized in that, The first filament extrusion unit also includes a material breakage sensor, which is mounted on the fixed base and has its detection end located inside the filament guide head.

6. The automatic feeding device for a 3D printer according to claim 1, characterized in that, The transverse component includes a slide rail stepper motor and a slider, the wire ejection die is mounted on the slider, and the slider is located at the movable end of the slide rail stepper motor.

7. The automatic feeding device for a 3D printer according to claim 6, characterized in that, The cutting unit includes a push rod motor, a cutting blade, and a cutting die. The push rod motor is vertically mounted on the slider, the cutting blade is located at the movable end of the push rod motor, and the cutting die is located inside the wire exiting die head. The push rod motor is used to drive the cutting blade to close and separate from the cutting die.

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