A feeding mechanism for a 3D printer

Abstract

The application discloses a kind of material feeding mechanism for 3D printer, belong to 3D printing equipment technical field, material feeding mechanism includes machine body, mobile seat, first material feeding component, second material feeding component, material guiding component and back-pumping buffer component.Two material feeding components are arranged in mobile seat, and are introduced into wire through flexible material guiding pipe and follow-up guide seat respectively.Back-pumping buffer component includes two groups of independent buffer units, each group of buffer units is provided with wire inlet guide, wire outlet guide, movable guide and constant force spring, and wire is formed around movable guide and forms return material section.Constant force spring drives movable guide to move, and stores back-pumping residual amount by changing return material section length, and releases wire when feeding again;Two groups of buffer units are provided with separator between it.The application can reduce the deflection and friction of wire when moving and feeding, relieve wire relaxation, accumulation and mutual interference when double color switching, improve the stability of feeding, back-pumping and feeding again.

Description

Technical Field

[0001] This invention belongs to the field of 3D printing equipment technology, and specifically relates to a feeding mechanism for a 3D printer. Background Technology

[0002] Fused deposition modeling (FDM) 3D printers use a feeding mechanism to deliver filament printing material to a heating element. The material melts under heat, is extruded through a nozzle, and deposits layer by layer along a pre-defined path to form the printed product. To meet the needs of two-color printing, some 3D printers are equipped with two feeding assemblies. Each assembly is connected to a corresponding filament tray and nozzle, allowing for two-color printing by switching the supply of different colors of filament. The two feeding assemblies can be mounted side-by-side on the same moving base. The filament is positioned on the frame, and the printing material is guided into the corresponding feeding assembly via a feed tube, completing the printing process as the moving base moves.

[0003] In the above-described material conveying arrangement, the guide position on the material tray side is relatively fixed, while the feed position of the conveying assembly moves with the moving seat. When there is a suspended material section between the outlet of the guide pipe and the feed inlet of the conveying assembly, and there is a lack of corresponding guiding constraints, the change in the position of the moving seat will cause changes in the bending shape and feed angle of this material section. The wire may deviate at the feed inlet and rub against the edge of the feed inlet, causing fluctuations in the feeding resistance. For two parallel conveying assemblies, if the range of motion of the wires in each path is not effectively restricted, slack wires may also enter the activity area of ​​adjacent material paths, affecting the stability of the feeding process.

[0004] Furthermore, in two-color printing processes where a retraction method is used to reduce ink spillage from non-working nozzles, the feed assembly, which pauses feeding, retracts the filament towards the tray. If the tray cannot promptly collect the retracted filament, and there are unconstrained sections in the guide path, the retracted filament may locally bend or accumulate. When feeding resumes, the feed assembly needs to first eliminate slack in the filament and re-establish a stable stress state, which can easily lead to inconsistent feeding responses. Significant local bending can also increase friction between the filament and the guide section, affecting the smoothness of retraction and refeeding. Relying solely on a fixed guide tube to determine the approximate filament transport path is insufficient to simultaneously accommodate changes in feed direction caused by the reciprocating motion of the moving seat, as well as the state changes caused by forward feeding and reverse retraction of the filament during two-color switching.

[0005] Therefore, how to maintain the guiding stability of the wire entering the feeding assembly during the dual-path feeding process, and effectively constrain the retracted wire to reduce wire skewing, local accumulation, and interference between the material paths, are technical problems that need to be solved. Summary of the Invention

[0006] To address the aforementioned shortcomings of existing technologies, this invention aims to solve the problem of existing 3D printer feeding mechanisms where the dual-filament wires deviate at the feed inlet and rub against the inlet edge, causing fluctuations in feeding resistance. During two-color printing, the retracted filament is prone to bending or accumulation. The purpose of this invention is to provide a feeding mechanism for 3D printers that, by providing follow-up guidance and retraction allowance for the two filament wires respectively, adapts the filament's guiding path to changes in the position of the feeding assembly, reduces filament slack, local accumulation, and mutual interference during two-color switching, and improves the stability of feeding, retraction, and refeeding.

[0007] To achieve the above objectives, the invention adopts the following technical solution: a feeding mechanism for a 3D printer, comprising: a body, a movable base, a first feeding component, a second feeding component, a guiding component, and a retraction buffer component. The movable base is movably mounted on the body horizontally and vertically via a guide rod. The first and second feeding components are arranged side by side on the movable base and each has a feed inlet, a feeding drive component, and a feeding channel corresponding to the feeding drive component. The two sets of feeding drive components can respectively drive the corresponding filament to be conveyed forward or retracted in the reverse direction along the feeding channel.

[0008] The material guiding assembly includes two sets of material guiding units respectively corresponding to the first material conveying assembly and the second material conveying assembly. Each set of material guiding units includes a fixed clamp, a flexible material guiding tube, and a follower guide seat. The fixed clamp is disposed on the machine body, and the follower guide seat is disposed on the movable seat and moves synchronously with the movable seat. The feed end of the flexible material guiding tube is connected to the fixed clamp, the flexible material guiding tube passes through the cover on the upper part of the machine body, and the wire at the discharge end is connected to the follower guide seat. The follower guide seat is provided with a transition guide channel communicating with the corresponding feed port, so that the wire enters the corresponding feeding channel from the flexible material guiding tube through the transition guide channel.

[0009] The retraction buffer assembly includes two sets of buffer units respectively corresponding to the two sets of material guiding units. Each set of buffer units is located at the front of the corresponding fixed clamp and includes a buffer bracket, an inlet guide, an outlet guide, a movable guide, and an elastic reset member. The inlet guide and the outlet guide are spaced apart from each other on the buffer bracket. The movable guide is movably mounted on the buffer bracket via a movable member. The wire passes through the inlet guide, the movable guide, and the outlet guide in sequence before entering the corresponding flexible material guide tube. The elastic reset member acts on the movable member, causing the movable guide to tend to move in a direction that increases the length of the wire's travel path.

[0010] When the corresponding feeding drive unit conveys the wire in the forward direction, the wire tension can drive the movable guide to overcome the action of the elastic reset member and move in the direction that reduces the wire's travel path length. When the corresponding feeding drive unit retracts the wire in the reverse direction, the movable guide unit moves in the direction that increases the wire's travel path length under the action of the elastic reset member to accommodate the excess wire generated during the retraction. The movable parts of the two sets of buffer units move independently.

[0011] According to another embodiment of the invention or any of the foregoing embodiments, a feeding mechanism for a 3D printer is provided on the machine body, wherein the machine body is provided with a tray support for carrying two trays respectively, the two sets of buffer units are respectively located on the discharge side of the corresponding tray, and the wire guide is arranged opposite to the wire inlet position of the corresponding fixed clamp.

[0012] According to another embodiment of the invention or any of the foregoing embodiments, a feeding mechanism for a 3D printer is provided, wherein the infeed guide and the outfeed guide are fixed guide wheels rotatably disposed on the buffer bracket, and the movable guide is a moving guide wheel rotatably disposed on the movable member; the buffer bracket is provided with a linear guide portion, the movable member slides in cooperation with the linear guide portion, and the moving guide wheel is capable of moving away from or towards the two fixed guide wheels, and the filament passes around the moving guide wheel to form a return section.

[0013] According to another embodiment of the invention or any of the foregoing embodiments, the feeding mechanism for a 3D printer is wherein the elastic reset member is a constant force spring, which is connected between the buffer bracket and the movable member, and is used to apply a reset force for accommodating excess filament to the moving guide wheel within the buffer stroke of the movable member.

[0014] According to another embodiment of the invention or any of the foregoing embodiments, a feeding mechanism for a 3D printer is provided, wherein the buffer bracket is provided with limiting parts that respectively limit two movement limit positions of the movable part, and the amount of filament collected corresponding to the stroke between the two movement limit positions is not less than the preset maximum retraction amount of the corresponding feeding component; in the normal feeding state, the movable part has a movement margin for collecting the retracted filament between itself and the limiting parts provided along the collection direction.

[0015] According to another embodiment of the invention or any of the foregoing embodiments, a feeding mechanism for a 3D printer is provided, wherein the circumferential surfaces of the fixed guide wheel and the moving guide wheel are respectively provided with guide grooves for accommodating filament, and the buffer bracket is provided with an anti-detachment limiting member corresponding to the guide groove, wherein a gap is left between the anti-detachment limiting member and the corresponding guide wheel for the filament to pass through, so as to restrict the filament from detaching from the guide groove.

[0016] According to another embodiment of the invention or any of the foregoing embodiments, a feeding mechanism for a 3D printer is provided, wherein a separator is provided between the two sets of buffer units, the separator separating the active areas of the two sets of movable guides and their corresponding return material sections, so that the two materials move within their respective buffer areas.

[0017] According to another embodiment of the invention or any of the foregoing embodiments, a feeding mechanism for a 3D printer is provided, wherein the two flexible guide tubes form curved sections between corresponding fixed clamps and follower guide seats, and the curved sections have deformation allowances to accommodate the working stroke of the moving seat; the moving seat is provided with arc-shaped bending limiting members corresponding to the two flexible guide tubes respectively, and each arc-shaped bending limiting member is located outside the discharge end of the corresponding flexible guide tube to limit local excessive bending of the discharge end.

[0018] According to another embodiment of the invention or any of the foregoing embodiments, a feeding mechanism for a 3D printer is provided, wherein the first feeding component and the second feeding component are respectively provided with a heating component and a nozzle, the heating component is located downstream of the corresponding feeding channel, and the nozzle is connected to the discharge end of the corresponding heating component; each feeding component is respectively provided with a heat sink and a fan, the heat sink is provided at the feeding part in front of the corresponding heating component, and the fan is provided facing the corresponding heat sink.

[0019] The beneficial effects of this invention are:

[0020] 1. This invention uses a flexible guide tube in conjunction with a follow-up guide seat to make the discharge end of the guide tube move synchronously with the moving seat, thereby reducing the skew and friction of the wire at the feeding part and improving the guiding stability during the moving feeding process.

[0021] 2. This invention uses an elastic reset component and a movable guide component to change the length of the wire's winding path. During retraction, the excess wire is collected, and during refeeding, the collected wire is released. This allows the excess wire to be stored and released within a constrained path, reducing local bending, accumulation, and slack, and improving the smoothness of retraction and refeeding.

[0022] 3. The present invention sets up a guiding unit and an independently moving buffer unit for the two lines respectively, and separates the buffer activity areas of the two lines by a separator, so that the two lines can adapt to the position changes of the conveying components and the forward and reverse conveying state changes respectively, reduce material path interference during the dual-color switching process, and improve the stability of dual-path material conveying. Attached Figure Description

[0023] Figure 1 This is a three-dimensional schematic diagram of the feeding mechanism for a 3D printer as described in the invention.

[0024] Figure 2A three-dimensional schematic diagram of the feeding mechanism for a 3D printer described in the invention, with the cover removed;

[0025] Figure 3 This is a schematic diagram showing the connection between the two material conveying components and the flexible guide tube described in the invention. Figure 1 ;

[0026] Figure 4 This is a schematic diagram showing the connection between the two material conveying components and the flexible guide tube described in the invention. Figure 2 ;

[0027] Figure 5 A schematic diagram of the operation of the retraction buffer assembly described in the invention;

[0028] In the diagram: 1. Machine body; 2. Moving seat; 3. First feeding assembly; 4. Second feeding assembly; 5. Fixed clamp; 6. Flexible guide tube; 7. Wire; 8. Material tray; 9. Nozzle; 10. Fan; 11. Guide rod; 12. Cover; 13. Buffer bracket; 14. Inlet guide; 15. Outlet guide; 16. Movable guide; 17. Constant force spring; 18. Separator. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] like Figure 1 and Figure 2 As shown, this embodiment provides a feeding mechanism for a 3D printer, including a body 1, a movable base 2, a first feeding assembly 3, a second feeding assembly 4, a guiding assembly, and a retraction buffer assembly. The movable base 2 cooperates with the body 1 via a guide rod 11, enabling it to move horizontally and vertically relative to the body 1. The first feeding assembly 3 and the second feeding assembly 4 are mounted side-by-side on the movable base 2, changing position together with the movable base 2 to meet the feeding needs at different locations during the printing process.

[0031] The machine body 1 is equipped with two tray supports, and two trays 8 are respectively mounted on the corresponding tray supports to provide wires 7 of different colors. Each tray 8 corresponds to a set of buffer units and a set of guiding units. After passing through the corresponding buffer units and guiding units, the two wires 7 enter the first conveying assembly 3 and the second conveying assembly 4. The two wires 7 have their own conveying paths and can be fed and withdrawn separately.

[0032] like Figure 3 and Figure 4As shown, both the first feeding assembly 3 and the second feeding assembly 4 have a feed inlet, a feeding drive, and a feeding channel. After the wire 7 enters the feeding channel through the feed inlet, the feeding drive acts on the wire 7 and drives it to move. The two sets of feeding drives operate independently, enabling the first feeding assembly 3 and the second feeding assembly 4 to independently perform forward feeding or reverse retraction according to printing needs.

[0033] The first feeding assembly 3 and the second feeding assembly 4 are respectively equipped with heating assemblies and nozzles 9. The heating assemblies are located downstream of the corresponding feeding channels, and the nozzles 9 are connected to the discharge end of the heating assemblies. The wire 7 enters the heating assembly under the action of the feeding drive, is heated and melted, and is extruded from the nozzles 9, thereby connecting the conveying and melting extrusion of the wire 7.

[0034] Each feeding assembly is also equipped with a heat sink and a fan 10. The heat sink is located at the feeding section in front of the heating assembly, and the fan 10 is positioned facing the corresponding heat sink. When the fan 10 is running, it causes air to flow through the heat sink, carrying away the heat from the front feeding section and reducing the possibility of the wire 7 softening due to heat before entering the predetermined heating zone, which would affect the conveying process.

[0035] like Figure 1 , Figure 3 and Figure 4 As shown, the material guiding assembly consists of two sets of material guiding units, arranged corresponding to the first material conveying assembly 3 and the second material conveying assembly 4, respectively. Each set of material guiding units includes a fixing clamp 5, a flexible material guiding tube 6, and a follower guide seat. The fixing clamp 5 is mounted on the machine body 1 and is used to fix the part of the flexible material guiding tube 6 near the feed end. The flexible material guiding tube 6 extends upward and passes through the cover 12 on the upper part of the machine body 1, with its discharge end facing the corresponding follower guide seat.

[0036] The follower guide seat is mounted on the movable seat 2, forming a transition guide channel inside. The outlet of the transition guide channel is connected to the corresponding feed port. After the wire 7 is led out from the outlet end of the flexible guide tube 6, it passes through the transition guide channel and then enters the feeding channel. The wire 7 can move forward or backward along the transition guide channel, and the follower guide seat guides the wire 7 as it passes through.

[0037] The follower guide seat and the movable seat 2 move synchronously, keeping the relative position of the outlet and the inlet of the transition guide channel stable. The wire 7 enters the inlet after passing through the transition guide channel, which helps to restrain the deviation of the wire 7 near the inlet position and reduces the situation where the wire 7 directly rubs against the edge of the inlet.

[0038] The flexible guide tube 6 forms a curved section between the fixed clamp 5 and the follower guide seat, and the curved section has a deformation margin to accommodate the working stroke of the moving seat 2. As the position of the moving seat 2 changes, the flexible guide tube 6 adapts to the change of the material path by adjusting the bending shape, avoiding increased pulling on the wire 7 due to the tension of the guide path.

[0039] The movable seat 2 is also equipped with two arc-shaped bending limiters, which are located on the outer side of the corresponding flexible guide tube 6 discharge end. When the discharge end of the flexible guide tube 6 bends towards the arc-shaped bending limiter, the arc-shaped bending limiter provides support and limit to that part, restricting the flexible guide tube 6 from local excessive bending near the discharge end and reducing the increase in internal resistance caused by this.

[0040] like Figure 5 As shown, the retraction buffer assembly includes two sets of buffer units serving the two wires 7 respectively. The two sets of buffer units are located on the discharge side of the corresponding trays 8 and in front of the fixing clamp 5, so that the wires 7 output from the trays 8 first pass through the buffer units and then enter the flexible guide tube 6.

[0041] Two sets of buffer units are mounted on buffer bracket 13, which adopts an integral backplate structure and is connected to the body 1 through mounting ears with mounting holes. Buffer bracket 13 provides a common mounting base for the two sets of buffer units, which facilitates the overall mounting of the retraction buffer assembly on the body 1 while maintaining the relative positions between the guide components.

[0042] Each buffer unit includes an inlet guide 14, an outlet guide 15, a movable guide 16, a movable component, and a constant force spring 17. The inlet guide 14 and the outlet guide 15 are spaced apart and mounted on the buffer bracket 13. The movable guide 16 is mounted on the movable component and moves relative to the buffer bracket 13 with the movable component. After the wire 7 is led out from the feed tray 8, it passes sequentially around the inlet guide 14, the movable guide 16, and the outlet guide 15, and then enters the corresponding flexible guide tube 6.

[0043] Both the infeed guide 14 and the outfeed guide 15 are fixed guide wheels that can rotate, while the movable guide 16 is a movable guide wheel that can rotate. When the wire 7 passes through each guide wheel, it can drive the guide wheel to rotate. The rotation of the guide wheel, in conjunction with the conveying of the wire 7, reduces the sliding friction when the wire 7 changes its direction of travel.

[0044] The buffer bracket 13 is provided with a linear guide, and the movable part slides in cooperation with the linear guide. In this embodiment, the inlet guide 14 and the outlet guide 15 are located above the movable guide 16. The movable part can move up and down along the linear guide, causing the movable guide 16 to move closer to or away from the two fixed guide wheels above. The wire 7 passes around the lower side of the movable guide 16 to form a return section.

[0045] When the movable guide 16 moves downward, the wire path on both sides of the return section is lengthened; when the movable guide 16 moves upward, the wire path on both sides of the return section is shortened. Therefore, the change in position of the movable guide 16 can be converted into a change in the length of the wire 7's bypass path, providing space for the storage of the retracted wire 7 and its release during refeeding.

[0046] like Figure 5 As shown, the constant force spring 17, acting as an elastic reset element of the buffer unit, is connected between the buffer bracket 13 and the movable component. Its direction of action causes the movable component to tend to move away from the two fixed guide wheels above. In this embodiment, the constant force spring 17 applies a downward reset force to the movable component, causing the movable guide component 16 to tend to increase the length of the return material section.

[0047] During forward feeding, the force exerted by the wire 7 on the movable guide 16 can cause the movable part to move upward against the reset action of the constant force spring 17, thus releasing the already stored wire 7. During reverse retraction, the retracted wire 7 creates a buffer path with available storage space, and the constant force spring 17 causes the movable part to move downward, accommodating this excess space by increasing the length of the return section.

[0048] The constant force spring 17 provides a relatively stable restoring force within its working stroke, which helps to reduce the variation in the restoring action when the moving part is in different positions. The restoring force of the constant force spring 17 is adapted to the conveying requirements of the wire 7, which can drive the moving part to collect the excess wire while avoiding adding excessive resistance to normal feeding.

[0049] The buffer bracket 13 is provided with two limiting parts, which respectively limit the two movement limit positions of the movable part. The buffer stroke of the movable part is formed between the two movement limit positions. The wire carrying amount corresponding to the buffer stroke is not less than the preset maximum retraction amount of the corresponding feeding assembly, so that the buffer unit has the ability to accommodate a predetermined retraction margin.

[0050] Under normal feeding conditions, a movement allowance is maintained between the movable part and the limiting part on the storage direction side. In this embodiment, this movement allowance is located below the movable part, allowing the movable part to continue moving downwards when retraction occurs. The amount of wire stored corresponding to this movement allowance is adapted to the predetermined retraction amount, preventing the movable part from reaching the limiting part too early and losing its ability to continue storing the wire 7.

[0051] like Figure 5 As shown, the circumferential surfaces of the inlet guide 14, the outlet guide 15, and the movable guide 16 are all provided with guide grooves, and the wire 7 travels along the guide grooves. The buffer bracket 13 is also provided with anti-detachment limiting members corresponding to the guide grooves, and a gap is maintained between the anti-detachment limiting members and the corresponding guide wheels for the wire 7 to pass through.

[0052] The guide groove defines the position of the wire 7 on the circumferential surface of the guide roller, while the anti-detachment limiting component restricts the wire 7 from moving away from the guide groove. Together, they reduce the likelihood of detachment when the feeding direction changes or the tension of the wire 7 changes, allowing the wire 7 to continue along the predetermined path around each guide roller. The anti-detachment limiting component corresponding to the movable guide 16 has an effective range covering the movement range of the movable guide 16, maintaining the anti-detachment effect within the buffer stroke.

[0053] A separator 18 is provided between the two sets of buffer units. The separator 18 extends along the area between the two sets of movable guides 16 and the return material section, separating the buffer movement space of the two wires 7. The two sets of movable parts move along their respective straight guides and are not connected to each other. Therefore, when one wire 7 is retracted or re-fed, it is not necessary to drive the other movable part to move together. The separator 18 further restricts the slack wire 7 from entering the adjacent buffer area, reducing contact and interference between the two wires 7.

[0054] Working principle of the invention:

[0055] Combination Figures 3 to 5 In this embodiment, the following guide and the variable length buffer path work together to adapt to the changes in the conveying state of the wire 7. The following guide moves with the moving seat 2 to maintain the relative position stability between the transition guide channel and the feed port; the flexible guide tube 6 adapts to the changes in the material path by bending and deforming, and the arc-shaped bending limiter restricts the local excessive bending at the discharge end of the flexible guide tube 6, thereby guiding the wire 7 into the conveying assembly.

[0056] The retraction buffer assembly adjusts the length of the return section by changing the position of the movable guide 16. When the movable guide 16 moves away from the two fixed guide rollers, the wire travel path lengthens, thus accommodating excess wire 7; when the movable guide 16 moves closer to the two fixed guide rollers, the wire travel path shortens, thus releasing the already accommodated wire 7. The constant force spring 17 provides a resetting function for the accommodating direction, and the tension of the wire 7 during feeding can drive the movable guide 16 to move in the opposite direction.

[0057] The two sets of buffer units respond to the tension and margin changes of the corresponding material paths, allowing the two material paths 7 to be in different feeding states. For example, when the first feeding assembly 3 retracts, its corresponding movable guide 16 moves in the receiving direction; the second feeding assembly 4 can continue to feed, and its corresponding movable guide 16 moves independently according to the force state of the material path 7.

[0058] The working process of this invention:

[0059] First, two trays 8 are installed on the tray support. Each wire 7 is led out from its corresponding tray 8, passes sequentially through the inlet guide 14, the movable guide 16, and the outlet guide 15, then enters the flexible guide tube 6, passes through the transition guide channel in the follower guide seat, enters the corresponding feed port, and enters the position of the feeding drive. After threading, the wire 7 is positioned within each guide groove, while the movable part retains sufficient movement in the storage direction to meet the predetermined retraction requirements.

[0060] At the start of printing, a set of feeding drive units drives the filament 7 to move forward along the feeding channel. If there is a retraction margin in the corresponding buffer unit, the tension of the filament 7 drives the movable guide 16 to move upward, gradually releasing the margin in the return section; as the filament 7 continues to be consumed, the feed tray 8 continues to release the filament 7. After being heated and melted by the heating component, the filament 7 is extruded by the nozzle 9.

[0061] During printing, the movable seat 2 moves the first feeding assembly 3, the second feeding assembly 4, and the follow-up guide seat to change positions. The flexible guide tube 6 adapts to changes in the material path by bending, and the transition guide channel guides the wire 7 entering the feed inlet. The fan 10 blows air to the corresponding heat sink to dissipate heat from the feeding part in front of the heating assembly.

[0062] When switching between two colors, taking the first feeding assembly 3 pausing feeding and the second feeding assembly 4 starting feeding as an example, the feeding drive in the first feeding assembly 3 runs in reverse, causing the first wire 7 to retract towards the material tray 8. The excess wire generated by the retraction is transmitted along the flexible guide tube 6 to the corresponding buffer unit. The constant force spring 17 drives the movable part and the movable guide part 16 to move downward, and the excess wire is collected by extending the return section. The second feeding assembly 4 and its corresponding buffer unit operate independently and do not need to retract simultaneously with the first wire 7.

[0063] When the first feeding component 3 participates in printing again, its feeding drive resumes forward operation, and the filament 7 drives the movable guide 16 to move upward, releasing the previously stored excess filament, and then continues to obtain filament 7 from the feed tray 8. Through the above process, the two filaments 7 complete feeding, retraction and refeeding respectively, realizing continuous feeding and switching in the two-color printing process.

[0064] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the above embodiments are merely illustrative of the technical concept and characteristics of the present invention, intended to enable those skilled in the art to understand and implement the invention, and should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A feeding mechanism for a 3D printer, comprising: The machine body (1), the movable seat (2), the first feeding assembly (3), the second feeding assembly (4), the guiding assembly and the retraction buffer assembly are arranged on the machine body (1) in a horizontal and vertical manner through the guide rod (11). The first feeding assembly (3) and the second feeding assembly (4) are arranged side by side on the movable seat (2) and each has a feed inlet, a feeding drive and a feeding channel corresponding to the feeding drive. The two sets of feeding drive can respectively drive the corresponding wire (7) to be conveyed in the forward direction or retracted in the reverse direction along the feeding channel. The material guiding assembly includes two sets of material guiding units respectively corresponding to the first material conveying assembly (3) and the second material conveying assembly (4). Each set of material guiding units includes a fixed clamp (5), a flexible material guiding tube (6), and a follow-up guide seat. The fixed clamp (5) is set on the machine body (1), and the follow-up guide seat is set on the moving seat (2) and moves synchronously with the moving seat (2). The feed end of the flexible material guiding tube (6) is connected to the fixed clamp (5), and the flexible material guiding tube (6) passes through the cover (12) on the upper part of the machine body (1). The wire (7) at the discharge end is connected to the follow-up guide seat. The follow-up guide seat is provided with a transition guide channel communicating with the corresponding feed inlet. The retraction buffer assembly includes two sets of buffer units respectively corresponding to the two sets of material guiding units. Each set of buffer units is located at the front of the corresponding fixed clamp (5) and includes a buffer bracket (13), an inlet guide (14), an outlet guide (15), a movable guide (16), and an elastic reset member. The inlet guide (14) and the outlet guide (15) are spaced apart on the buffer bracket (13). The movable guide (16) is movably mounted on the buffer bracket (13) through a movable member. The wire (7) passes through the inlet guide (14), the movable guide (16), and the outlet guide (15) in sequence and then enters the corresponding flexible material guiding tube (6). The moving parts of the two sets of buffer units move independently.

2. The feeding mechanism for a 3D printer according to claim 1, characterized in that: The machine body (1) is provided with support members for carrying two material trays (8), and the two sets of buffer units are respectively located on the discharge side of the corresponding material tray (8). The wire guide (15) is arranged opposite to the wire inlet position of the corresponding fixing clamp (5).

3. The feeding mechanism for a 3D printer according to claim 1, characterized in that: The infeed guide (14) and the outfeed guide (15) are fixed guide wheels rotatably mounted on the buffer bracket (13), and the movable guide (16) is a moving guide wheel rotatably mounted on the movable member; the buffer bracket (13) is provided with a linear guide part, the movable member slides with the linear guide part, and the moving guide wheel can move in a direction away from or close to the two fixed guide wheels, and the wire (7) passes around the moving guide wheel to form a return section.

4. A feeding mechanism for a 3D printer according to claim 1 or 3, characterized in that: The elastic reset component is a constant force spring (17), which is connected between the buffer bracket (13) and the movable component. It is used to apply a reset force to the moving guide wheel within the buffer stroke of the movable component to accommodate the excess wire (7).

5. A feeding mechanism for a 3D printer according to claim 4, characterized in that: The buffer bracket (13) is provided with limiting parts that respectively limit the two movement limit positions of the movable part. The amount of wire (7) stored corresponding to the stroke between the two movement limit positions is not less than the preset maximum retraction amount of the corresponding feeding component. In the normal feeding state, the movable part has a movement margin for storing the retracted wire (7) between itself and the limiting parts set along the storage direction.

6. A feeding mechanism for a 3D printer according to claim 3, characterized in that: The circumferential surfaces of the fixed guide wheel and the moving guide wheel are respectively provided with guide grooves for accommodating the wire (7). The buffer bracket (13) is provided with anti-detachment limiting members corresponding to the guide grooves. A gap is left between the anti-detachment limiting members and the corresponding guide wheel for the wire (7) to pass through, so as to restrict the wire (7) from leaving the guide groove.

7. A feeding mechanism for a 3D printer according to claim 1, characterized in that: A separator (18) is provided between the two sets of buffer units. The separator (18) separates the active areas of the two sets of movable guides (16) and their corresponding return material sections, so that the two materials (7) can move within their respective buffer areas.

8. A feeding mechanism for a 3D printer according to claim 1, characterized in that: The two flexible guide tubes (6) form a curved section between the corresponding fixed clamp (5) and the follower guide seat. The curved section has a deformation allowance to accommodate the working stroke of the moving seat (2). The moving seat (2) is provided with arc-shaped bending limiters corresponding to the two flexible guide tubes (6). Each arc-shaped bending limiter is located outside the discharge end of the corresponding flexible guide tube (6) to limit the local excessive bending of the discharge end.

9. A feeding mechanism for a 3D printer according to claim 1, characterized in that: The first feeding component (3) and the second feeding component (4) are respectively provided with a heating component and a nozzle (9). The heating component is located downstream of the corresponding feeding channel, and the nozzle (9) is connected to the discharge end of the corresponding heating component. Each feeding component is respectively provided with a heat sink and a fan (10). The heat sink is located at the feeding part in front of the corresponding heating component, and the fan (10) is directed toward the corresponding heat sink.

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