FDM printing multi-jet quick positioning switching mechanism, jet assembly and 3D printer

Abstract

The application relates to the field of 3D printers, and particularly provides an FDM printing multi-nozzle quick positioning and switching mechanism, a nozzle assembly and a 3D printer. The positioning and switching mechanism comprises a connecting piece and a driving motor, is used for connecting a rotating disc with a nozzle structure, the driving motor is used for driving the rotating disc to rotate, the switching mechanism further comprises a harmonic reducer and a control piece, the output end of the driving motor is fixedly connected with the input end of the harmonic generator, the output end of the harmonic reducer is fixedly connected with the connecting piece, the number of teeth of a fixed wheel in the harmonic generator is an integer multiple of the number of nozzles on the rotating disc, and the control piece controls the driving motor to rotate a preset number of turns after receiving a nozzle switching command. The application utilizes the characteristics of high precision and high rigidity of the harmonic reducer, realizes quick and accurate positioning and switching of the multiple nozzles on the rotating disc, and effectively avoids positioning errors caused by gaps and backlashes of traditional mechanisms.

Description

Technical Field

[0001] This invention relates to the field of 3D printers, and more particularly to an FDM printing multi-nozzle rapid positioning and switching mechanism, a nozzle assembly, and a 3D printer. Background Technology

[0002] In the field of fused deposition modeling (FDM) 3D printing technology, multi-nozzle printing technology has greatly expanded the application scope of 3D printing due to its ability to achieve composite printing of multiple materials, multiple colors, or materials with different properties, becoming an important direction for current research and application. The core of multi-nozzle printing lies in the nozzle switching mechanism, the performance of which directly affects printing efficiency and print quality.

[0003] Traditional FDM multi-head switching mechanisms come in two forms. One type places multiple printheads individually in a specific area of ​​the printer (e.g., patent publication number CN106493944A), forming a printhead library. During printing, the corresponding color printhead is clamped to complete color printing. This method involves a large amount of idle travel during color switching, affecting printing efficiency. The other type installs multiple printheads in the same location (e.g., patent publication numbers CN105965898B and CN108248017A), using a rotary structure to switch printheads. While this method offers higher switching efficiency, it often uses gear or belt drives and requires specialized clamping and positioning mechanisms; otherwise, vibration can cause inaccurate printhead positioning, affecting printing accuracy. To address these issues, this application proposes an FDM printing multi-head rapid positioning and switching mechanism, a printhead assembly, and a 3D printer. Summary of the Invention

[0004] The purpose of this invention is to provide an FDM printing multi-nozzle rapid positioning and switching mechanism, a nozzle assembly, and a 3D printer to solve the problem of excessive spatial travel when switching printing nozzles in current multi-nozzle printers.

[0005] To achieve the above objectives, the present invention provides the following technical solution: An FDM printing multi-nozzle rapid positioning and switching mechanism includes a connector and a drive motor for connecting a turntable with a nozzle structure. The drive motor drives the turntable to rotate. The switching mechanism also includes a harmonic reducer and a control unit. The output end of the drive motor is fixedly connected to the input end of a harmonic generator, and the output end of the harmonic reducer is fixedly connected to the connector. The number of teeth on the fixed wheel in the harmonic generator is an integer multiple of the number of nozzles on the turntable. After receiving a nozzle switching command, the control unit controls the drive motor to rotate a preset number of revolutions.

[0006] Furthermore, the outer edge of the wave generator of the harmonic reducer is in surface contact with the inner wall of the flex wheel, and when the turntable rotates to the preset position, at least two teeth on the flex wheel mesh with the inner teeth of the rigid wheel.

[0007] Furthermore, the switching mechanism also includes: A clamping member is used to fix the input end of the harmonic reducer when the drive motor stops.

[0008] Furthermore, the clamping element includes: The V-shaped positioning grooves are located on the housing of the resonant reducer. The number of V-shaped positioning grooves is the same as the number of nozzles. The V-shaped positioning grooves are evenly distributed around the axis of the input end of the resonant reducer in the circumferential direction. A follower limiting shell is fixedly connected to the input end of the resonant reducer, and the follower limiting shell is located outside the pitch circle formed by the V-shaped limiting shell; The positioning block has an arc-shaped positioning surface on the side that contacts the V-shaped positioning groove. The positioning block slides radially along the follower limiting shell and has axial and circumferential limiting. A return spring is located between the positioning block and the follower limiting shell, and applies a force to the positioning block to give it a tendency to move toward the V-shaped positioning groove.

[0009] Furthermore, the input end of the resonant reducer is provided with a limiting block distributed circumferentially around its axis, and the follower limiting shell is provided with a circumferential limiting groove that matches the limiting block. The follower limiting shell has axial limiting at the input end of the resonant reducer.

[0010] Furthermore, there is a smooth transition between adjacent V-shaped positioning grooves.

[0011] Furthermore, the switching mechanism also includes: A position detection component is used to detect the position of the turntable, and the control component controls the rotational speed of the drive motor based on the position of the turntable.

[0012] Furthermore, the control unit controls the drive motor to operate in a manner of increasing speed, maintaining constant speed, and decreasing speed.

[0013] The present invention also discloses a printhead assembly, including multiple independent printheads, and the aforementioned FDM printing multi-printhead rapid positioning and switching mechanism.

[0014] The present invention also discloses a 3D printer including the above-described nozzle assembly.

[0015] In summary, the present invention has the following advantages compared with the prior art: The FDM printing multi-nozzle rapid positioning and switching mechanism disclosed in this invention transmits the power of the drive motor through a harmonic reducer. Utilizing the high precision and high rigidity of the harmonic reducer, it achieves rapid and accurate positioning and switching of multiple nozzles on the turntable, effectively avoiding positioning errors caused by backlash and hysteresis in traditional mechanisms. At the same time, due to the precise meshing between the flexible and rigid wheels, the gap problem commonly found in traditional transmission structures is improved, further enhancing the positioning repeatability and dynamic response performance of the system. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the FDM printing multi-nozzle rapid positioning and switching mechanism disclosed in an embodiment of the present invention.

[0017] Figure 2 This is a front view of the FDM printing multi-nozzle rapid positioning and switching mechanism disclosed in an embodiment of the present invention.

[0018] Figure 3 for Figure 2 Sectional view of AA.

[0019] Figure 4 This is an exploded view of the FDM printing multi-nozzle rapid positioning and switching mechanism disclosed in an embodiment of the present invention.

[0020] Figure 5 This is a schematic diagram of the cooperation between the V-shaped positioning groove and the positioning block in the FDM printing multi-nozzle rapid positioning and switching mechanism disclosed in an embodiment of the present invention.

[0021] Figure 6 This is a schematic diagram of the end cap structure of the FDM printing multi-nozzle rapid positioning and switching mechanism disclosed in an embodiment of the present invention.

[0022] Figure 7 This is a schematic diagram of the positioning block in the FDM printing multi-nozzle rapid positioning and switching mechanism disclosed in an embodiment of the present invention.

[0023] Figure 8 This is a schematic diagram showing the connection between the FDM printing multi-nozzle rapid positioning and switching mechanism and the turntable disclosed in an embodiment of the present invention.

[0024] Figure label: 100. Connector; 200. Harmonic damper; 210. Flexible wheel; 220. Wave generator; 221. Connecting shaft; 222. Limiting block; 230. Rigid wheel; 240. End cap; 241. Positioning platform; 242. V-shaped positioning groove; 300. Clamping component; 310. Follower limiting shell; 311. Radial limiting hole; 312. Circumferential limiting groove; 320. Positioning block; 321. Positioning surface; 322. Limiting shaft; 330. Return spring; 340. Locking nut; 400. Turntable. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0026] Example 1 like Figures 1 to 6 As shown in one embodiment of the present invention, this embodiment discloses an FDM printing multi-nozzle rapid positioning and switching mechanism, comprising a connector, a drive motor (not shown in the figure), a harmonic reducer, and a control component (not shown in the figure). The turntable connector is used to connect to a turntable with a nozzle structure. The drive motor is used to drive the turntable to rotate. The output end of the drive motor is fixedly connected to the input end of the harmonic generator. The output end of the harmonic reducer is fixedly connected to the connector. The number of teeth on the fixed wheel in the harmonic generator is an integer multiple of the number of nozzles on the turntable. After receiving a nozzle switching command, the control component controls the drive motor to rotate a preset number of revolutions.

[0027] In this embodiment, as Figure 8 As shown, the turntable is fixedly connected to the output end of the resonant reducer via a connector. The nozzle is mounted on the turntable, and the resonant reducer and the drive motor are fixed to the printing end of the 3D printer. During nozzle switching, the drive motor drives the wave generator of the harmonic reducer to rotate. The wave generator transmits power to the output end of the harmonic reducer (i.e., the flexible wheel) through the meshing of a flexible wheel and a rigid wheel, thereby driving the connector and turntable to rotate. When the drive motor rotates a preset number of times, the output end of the harmonic reducer rotates by a preset angle, thus driving the turntable to rotate to the corresponding position of the target nozzle via the connector, achieving precise positioning and switching. During the positioning process, the meshing between the flexible and rigid wheels has high-precision transmission characteristics, effectively eliminating backlash and ensuring accurate positioning each time the turntable stops. Since the number of teeth on the rigid wheel is an integer multiple of the number of nozzles on the turntable, it ensures that each nozzle position corresponds to a fixed angular displacement. When the turntable rotates to the preset position, the teeth of the flexible wheel and the rigid wheel are fully meshed, forming precise positioning and locking, thus achieving precise positioning and locking of the turntable.

[0028] The FDM printing multi-nozzle rapid positioning and switching mechanism disclosed in this invention transmits the power of the drive motor through a harmonic reducer. Utilizing the high precision and high rigidity of the harmonic reducer, it achieves rapid and accurate positioning and switching of multiple nozzles on the turntable, effectively avoiding positioning errors caused by backlash and hysteresis in traditional mechanisms. At the same time, due to the precise meshing between the flexible and rigid wheels, the gap problem commonly found in traditional transmission structures is improved, further enhancing the positioning repeatability and dynamic response performance of the system.

[0029] Specifically, in this embodiment, the drive motor is a stepper motor, a technology already in use. It precisely controls the rotation angle via pulse signals, and combined with a harmonic reducer, achieves high repeatability and positioning accuracy for each step. The motor rotates a fixed angle for each pulse signal received; after being amplified by the reduction ratio, the output receives a smaller angular displacement, thus accurately positioning the motor to the target nozzle position. Through precise control of the pulse signals, the drive motor can achieve micron-level adjustment of the turntable's rotation angle, ensuring rapid and accurate positioning of each nozzle during switching.

[0030] like Figures 3 to 5 The harmonic reducer described is existing technology. In this embodiment, the harmonic reducer consists of a wave generator, a flexible wheel, a rigid wheel, and an end cap. The flexible wheel is rotatably connected to the inner side of the rigid wheel. The rigid wheel has a grooved structure with straight teeth on its inner wall and straight teeth on its outer side. The rigid wheel and flexible wheel mesh. The end cap is bolted to the opening of the rigid wheel. The rigid wheel and flexible wheel form a hollow cavity structure. The wave generator is rotatably connected to the end cap and is located within the cavity structure formed by the rigid wheel and flexible wheel. Its working principle is based on elastic deformation transmission, which has the advantages of high torque density, low backlash, and high positioning accuracy. During nozzle switching, the wave generator, as the input end, drives the flexible wheel to produce periodic elastic deformation through an elliptical contour, enabling continuous meshing and disengagement of the outer teeth of the flexible wheel and the inner teeth of the rigid wheel, thereby outputting a stable angular displacement. Because the flexible wheel material possesses excellent fatigue strength and resilience, it ensures that transmission accuracy is maintained even during long-term operation. Meanwhile, the rigid wheel is fixed to the printing end structure, which effectively improves the overall system rigidity.

[0031] The wave generator is equipped with a connecting shaft, and the output end of the drive motor is connected to the connecting shaft of the wave generator through the connecting shaft, thereby driving the wave generator to rotate synchronously and transmitting the power of the drive motor to the inside of the harmonic reducer.

[0032] Preferably, in this embodiment, the outer edge of the wave generator of the harmonic reducer is in surface contact with the inner wall of the flexure. When the turntable rotates to the preset position, at least two teeth on the flexure mesh with the inner teeth of the rigid wheel, thereby effectively dispersing the meshing stress and improving transmission smoothness and load-bearing capacity. The multi-tooth meshing state forms a self-locking effect at the moment of positioning, further suppressing micro-amplitude vibration and ensuring static stability after the nozzle position is switched. At the same time, multi-tooth meshing can also effectively improve positioning accuracy and reduce the off-center load caused by single-tooth meshing.

[0033] It should be noted that each nozzle installed on the turntable is circumferentially mounted on the turntable, with equal included angles between adjacent nozzles, ensuring that the positioning positions are evenly distributed during rotation switching. In conjunction with the pulse equivalent of the drive motor and the reduction ratio of the harmonic reducer, precise equal division and positioning of the entire circumference can be achieved.

[0034] The control component is existing technology. In this embodiment, the control component, MCU control unit, is responsible for receiving instructions from the host computer and parsing motion parameters, and for precisely controlling the rotation angle and speed of the drive motor through pulse signals.

[0035] The connector is existing technology. Depending on user settings, as in this embodiment, the connector includes two flange plates connected by a shaft. In some other embodiments, the connector may also be a bolted structure, used only for connecting the flexible wheel and the turntable.

[0036] Example 2 As another embodiment of the invention, such as Figures 3 to 7 As shown, the difference between this embodiment and Embodiment 1 is that the positioning switching mechanism further includes a clamping member, which fixes the input end of the harmonic reducer when the drive motor stops. Specifically, in this embodiment, the clamping member is fixedly connected to the connecting shaft and the end cover, and the clamping member is used to fix the connecting shaft of the wave generator to prevent it from rotating slightly due to external disturbances when stationary.

[0037] In a preferred embodiment of this invention, the clamping member includes a V-shaped positioning groove, a follower limiting shell, a positioning block, and a return spring. The V-shaped positioning groove is located on the housing of the resonant reducer, and the number of V-shaped positioning grooves is the same as the number of nozzles. The V-shaped positioning grooves are evenly distributed circumferentially around the axis of the input end of the resonant reducer. The follower limiting shell is fixedly connected to the input end of the resonant reducer, and the follower limiting shell is located outside the pitch circle formed by the V-shaped limiting shell. The side of the positioning block that contacts the V-shaped positioning groove is an arc-shaped positioning surface. The positioning block slides radially along the follower limiting shell and has axial and circumferential limiting. The return spring is located between the positioning block and the follower limiting shell and applies force to the positioning block to make it have a tendency to move towards the V-shaped positioning groove. When the drive motor drives the wave generator to rotate, the drive motor drives the follower limiting shell to rotate synchronously through the connecting shaft. Under the action of centrifugal force, the positioning block overcomes the spring force of the reset spring and slides outward radially, disengaging from the V-shaped positioning groove, thus realizing automatic unlocking of the clamping part. When the turntable rotates to the preset position, the drive motor stops, the follower limiting shell stops synchronously, and the reset spring pushes the positioning block to re-embed into the corresponding V-shaped positioning groove. The arc-shaped positioning surface fits tightly with the wall of the V-shaped groove, forming a rigid positioning support, which effectively suppresses the slight rebound and vibration at the input end of the harmonic reducer, further improving the repeatability accuracy of nozzle switching positioning and the stability of the system's dynamic response.

[0038] Specifically, in this embodiment, a positioning platform is provided on the end cap. The positioning platform has a frustum structure, and the V-shaped positioning grooves are provided on the side of the positioning platform and evenly distributed circumferentially to match the number of nozzles and indexing requirements. The positioning platform and the end cap are integrally formed to ensure structural strength and coaxiality accuracy. The follower limiting shell has a circular groove structure, with the groove opening facing the positioning platform. Its inner wall maintains a radial clearance fit with the outer circumference of the positioning platform. The follower limiting shell has radial limiting holes penetrating its sidewalls. The side of the positioning block that contacts the V-shaped positioning groove is an arc-shaped positioning surface. Since the positioning block is arranged radially, when the arc-shaped positioning surface and the inclined surface of the V-shaped positioning groove are in contact, machining and assembly errors can be automatically compensated, ensuring that the positioning block achieves self-centering during the embedding process and improving positioning reliability. The positioning block is equipped with a limiting shaft, which is radially arranged. A return spring is sleeved on the limiting shaft, with one end abutting against the inner wall of the follower limiting shell and the other end abutting against the positioning block, providing a continuous inward restoring force. When the drive motor stops, the centrifugal force disappears, and the return spring pushes the positioning block to slide radially inward, so that the arc-shaped positioning surface gradually corresponds to the inclined surface of the V-shaped positioning groove until it is fully engaged, achieving precise positioning and locking of the turntable. The limiting shaft is axially limited on the outside of the follower limiting shell by a retaining spring, preventing the positioning block from axially falling off during radial sliding and ensuring stable and reliable movement.

[0039] In a preferred embodiment of this invention, the adjacent V-shaped positioning grooves have a smooth transition, such as... Figure 6 As shown in this embodiment, there are six nozzles and a corresponding number of V-shaped positioning grooves, which are evenly distributed around the circumference of the positioning platform. The included angle between every two adjacent V-shaped positioning grooves is 60 degrees, which enables the nozzles to switch at equal intervals of 60 degrees. Adjacent V-shaped positioning grooves are connected by rounded corners, so that when the positioning block rotates with the follower limiting shell, the positioning surface of the positioning block smoothly transitions between the V-shaped positioning grooves, thereby reducing its wear.

[0040] Preferably, in this embodiment, the input end of the resonant reducer is provided with limiting blocks distributed circumferentially around its axis, and the follower limiting shell is provided with a circumferential limiting groove matching the limiting blocks, thus providing axial limiting at the input end of the resonant reducer. Specifically, in this embodiment, the connecting shaft is provided with multiple limiting blocks, which are evenly distributed circumferentially and engage with the circumferential limiting groove at the input end of the resonant reducer to achieve stable torque transmission. A locking nut is threaded onto the connecting shaft, which is used to axially press and fix the follower limiting shell onto the connecting shaft, ensuring no axial movement between the input end of the resonant reducer and the follower limiting shell, thereby improving transmission accuracy and system stability. The locking nut is tightened to a set torque using a torque wrench to prevent loosening due to vibration during operation, further ensuring reliable connection of the structure.

[0041] Example 3 As another embodiment of the invention, this embodiment differs from Embodiments 1 and 2 in that the switching mechanism further includes a position detection element for detecting the position of the turntable, and the control element controls the rotational speed of the drive motor based on the position of the turntable.

[0042] In this embodiment, the position detection device is a photoelectric encoder, which is installed on the output shaft end of the drive motor. It collects the rotation angle of the turntable in real time and feeds it back to the control device. The drive motor performs closed-loop control based on the angle signal fed back by the photoelectric encoder. When the turntable approaches the target position, the control device automatically reduces the motor speed to achieve slow entry and accurate positioning, avoiding positioning deviation caused by inertial overshoot.

[0043] In this embodiment, the controller controls the drive motor to operate in a speed-increasing, constant-speed, and speed-decelerating manner. After the drive motor starts, it first rapidly increases the turntable speed in the speed-increasing phase to shorten the idle travel time; after entering the constant-speed phase, it maintains stable rotation to ensure smooth operation; when approaching the target position, the controller enters the speed-decelerating phase based on the feedback signal from the photoelectric encoder, gradually reducing the speed until it stops, achieving precise positioning.

[0044] Example 4 As another embodiment of the invention, the present invention also discloses a printhead assembly including multiple independent printheads, and the FDM printing multi-printhead rapid positioning and switching mechanism described in any of Embodiments 1, 2 or 3, wherein the printheads are fixed to a turntable.

[0045] Example 5 As another embodiment of the invention, the present invention also discloses a 3D printer including the nozzle assembly described in embodiment 4.

[0046] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular forms “a,” “the,” and “the” used in this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0047] It should be understood that although the terms first, second, third, etc., may be used in this invention to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, first information may also be referred to as second information without departing from the scope of this invention, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to a determination."

[0048] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An FDM printing multi-nozzle rapid positioning and switching mechanism, comprising a connector and a drive motor for connecting a turntable with a nozzle structure, wherein the drive motor is used to drive the turntable to rotate, characterized in that, The switching mechanism further includes: A harmonic reducer, wherein the output end of the drive motor is fixedly connected to the input end of the harmonic generator, and the output end of the harmonic reducer is fixedly connected to a connector, wherein the number of teeth on the fixed wheel in the harmonic generator is an integer multiple of the number of nozzles on the turntable; The control unit controls the drive motor to rotate a preset number of revolutions after receiving the nozzle switching command.

2. The FDM printing multi-head rapid positioning and switching mechanism according to claim 1, characterized in that, The outer edge of the wave generator of the harmonic reducer is in surface contact with the inner wall of the flex wheel. When the turntable rotates to the preset position, at least two teeth on the flex wheel mesh with the inner teeth of the rigid wheel.

3. The FDM printing multi-head rapid positioning and switching mechanism according to claim 1 or 2, characterized in that, The switching mechanism further includes: A clamping member is used to fix the input end of the harmonic reducer when the drive motor stops.

4. The FDM printing multi-head rapid positioning and switching mechanism according to claim 3, characterized in that, The clamping element includes: The V-shaped positioning grooves are located on the housing of the resonant reducer. The number of V-shaped positioning grooves is the same as the number of nozzles. The V-shaped positioning grooves are evenly distributed around the axis of the input end of the resonant reducer in the circumferential direction. A follower limiting shell is fixedly connected to the input end of the resonant reducer, and the follower limiting shell is located outside the pitch circle formed by the V-shaped limiting shell; The positioning block has an arc-shaped positioning surface on the side that contacts the V-shaped positioning groove. The positioning block slides radially along the follower limiting shell and has axial and circumferential limiting. A return spring is located between the positioning block and the follower limiting shell, and applies a force to the positioning block to give it a tendency to move toward the V-shaped positioning groove.

5. The FDM printing multi-head rapid positioning and switching mechanism according to claim 4, characterized in that, The input end of the resonant reducer is provided with a limiting block distributed circumferentially around its axis, and the follower limiting shell is provided with a circumferential limiting groove that matches the limiting block. The follower limiting shell has axial limiting at the input end of the resonant reducer.

6. The FDM printing multi-head rapid positioning and switching mechanism according to claim 4, characterized in that, The adjacent V-shaped positioning grooves have a smooth transition.

7. The FDM printing multi-head rapid positioning and switching mechanism according to claim 1 or 2, characterized in that, The switching mechanism further includes: A position detection component is used to detect the position of the turntable, and the control component controls the rotational speed of the drive motor based on the position of the turntable.

8. The FDM printing multi-head rapid positioning and switching mechanism according to claim 7, characterized in that, The control unit controls the drive motor to operate in a manner of increasing speed, maintaining constant speed, and decreasing speed.

9. A nozzle assembly comprising a plurality of independent nozzles, characterized in that, It also includes the FDM printing multi-nozzle rapid positioning and switching mechanism as described in any one of claims 1-8.

10. A 3D printer, characterized in that, Includes the nozzle assembly as described in claim 9.

Images