CN105415691A - Cylindrical coordinate type 3D printer capable of achieving simultaneous multi-spray-head printing - Google Patents

Abstract

The invention relates to a cylindrical coordinate 3D printer capable of simultaneously printing with multiple nozzles. It includes an external meshing precision planetary gear mechanism, a telescopic cantilever beam mechanism, a Z-axis motion mechanism, and a feeding mechanism; the external meshing precision planetary gear mechanism is composed of a sun gear, a planetary gear, a support block, a reinforced ring and a disc-shaped working platform; the telescopic cantilever beam mechanism includes a nozzle, a feeding motor, a Z motion block, a polar axial drive motor, a polar axial ball screw and a limit block; the Z axis motion mechanism includes a Z drive motor, a Z The supporting frame of the moving mechanism, the Z-directing ball screw, the planetary gear drive motor and the motor seat; the feeding mechanism includes a feeding wheel and a feeding wheel supporting frame. The printing of the polar coordinate plane is realized through the external meshing precision planetary gear mechanism and the telescopic arm beam mechanism, and the Z-axis control mechanism realizes the Z-direction movement, thereby realizing the 3D printing movement of the nozzle. Multi-nozzle processing at the same time.

Description

A cylindrical coordinate 3D printer capable of simultaneous printing with multiple nozzles

technical field

The present invention relates to a cylindrical coordinate 3D printer capable of simultaneously printing with multiple nozzles. In order to solve the problem that the nozzles of the current multi-nozzle 3D printer are prone to interference and that the multi-nozzle printer can only have one nozzle working at most at the same time , and the problems of slow speed and low precision of printing rotary parts by 3D printers at present, the structure of this 3D printer is proposed.

technical background

3D printing is a kind of rapid prototyping technology. It is a technology based on digital model files and using bondable materials such as powdered metal or plastic to construct objects by layer-by-layer printing.

The existing 3D printers can only achieve single nozzle or multi-nozzle single nozzle due to the structural design. Today, in the pursuit of efficiency, it seriously affects the speed of 3D printing and limits the efficiency of 3D printing. Therefore, there is an urgent need for a multi-nozzle. The structure of the 3D printer that the nozzles co-spray and print simultaneously improves the printing speed of the 3D printer.

The accuracy of existing 3D printers is generally not high, and the accuracy is even worse when the printing trajectory is a curve, which makes the existing 3D printers unsuitable for printing shaft and rotary parts, so a class of 3D printers is urgently needed to fill this gap.

Contents of the invention

The object of the present invention is to address the above disadvantages, to provide a cylindrical coordinate 3D printer capable of simultaneously printing with multiple nozzles, which can realize multi-nozzle printing, multi-color printing, and improve the printing accuracy and speed of the curved track, and improve the printing accuracy of the printer. Printer structure for efficiency and quality.

The technical scheme adopted by a cylindrical coordinate 3D printer capable of simultaneously printing with multiple nozzles in the present invention is:

A cylindrical coordinate 3D printer capable of simultaneously printing with multiple nozzles includes an external meshing precision planetary gear mechanism, a retractable cantilever beam mechanism, a Z-axis motion mechanism, and a feeding mechanism.

The external meshing precision planetary gear mechanism is composed of sun gears, planetary gears, support blocks, reinforcing rings and disc-shaped worktables. There are at least two planetary gears. This example takes a double print head as an example, so there are two planetary gears, planetary gear A and planetary gear B. Among them, the sun gear, reinforced ring and disc-shaped worktable in the precision planetary gear mechanism are fixed on the support block, the number of support blocks is arbitrary, and the number is preferably an even number, and the distribution method should be evenly distributed among the reinforced ring, etc. On the point.

In the external meshing precision planetary gear mechanism, the planetary gear is installed on the output shaft of the driving motor of the external meshing precision planetary gear mechanism, and is externally meshed with the sun gear. There is also a reinforced ring concentric with the sun gear in the outer meshed precision planetary gear mechanism on the same plane, and a disc-shaped workbench is arranged inside the reinforced ring. The disc-shaped workbench is concentric with the reinforced ring and the sun gear.

Further, in the external meshing precision planetary gear mechanism, the sun gear and the reinforcing ring are fixed in the slots on the support blocks below them, the number of support blocks is arbitrary, and the number is preferably an even number, and the distribution method should be evenly distributed among Reinforced at the bisecting point of the ring.

The telescopic cantilever beam mechanism includes a spray head, a feeding motor, a Z movement block, a polar axial drive motor, a polar axial ball screw and a limit block. There are at least two spray heads in the telescopic cantilever beam mechanism. This example takes double nozzles as an example, so there are two sets of retractable cantilever beam structures, which are: nozzle A, feeding motor A, Z-direction moving block A, polar axial drive motor A, polar axial ball screw A, Limiting block A, nozzle B, feeding motor B, Z-direction movement block B, pole-axis drive motor B, pole-axis ball screw B, and limit block B. The polar axial drive mode is driven by ball screw pair transmission, and it can also be realized by choosing reasonable mechanisms such as worm gear and worm gear and synchronous belt. Among them, the polar axial ball screw and the polar axial drive motor are fixed on the Z-direction movement block, the feeding drive motor and nozzle are installed on one end of the polar axial ball screw, and the other end has a limit block, the limit The block prevents the over-travel of the axial movement of the pole and avoids damage to the mechanism.

Further, in the retractable cantilever beam mechanism, the driving mode in the polar axis direction can be selected from various forms such as ball screw, worm gear and worm gear, and synchronous belt transmission mechanism, and the ball screw is selected here. The polar axial ball screw and the polar axial drive motor are fixed on the Z-direction movement block. A nozzle and a feeding motor are installed on one section of the polar axial ball screw, and a limit block is installed on the other end.

The Z-axis motion mechanism includes a Z-direction drive motor, a Z-direction motion mechanism support frame, a Z-direction ball screw, a planetary gear drive motor, and a motor base. There are at least two sets of Z-axis motion mechanisms. This example takes the dual-nozzle printing mechanism as an example. There are two sets of Z-direction motion mechanisms, which are: Z-direction drive motor A, Z-direction motion mechanism support frame A, Z-direction ball screw A, planetary gear mechanism drive motor A, motor Seat A, Z-direction drive motor B, Z-direction motion mechanism support frame B, Z-direction ball screw B, planetary gear mechanism drive motor B, motor seat B. Among them, the planetary gear drive motor is fixed on the motor base, and the Z-axis motion device is installed on the sun gear and the reinforced ring through the motor base. The Z-direction drive mode is selected as a ball screw or a synchronous belt drive. , The Z-direction ball screw is fixed on the support frame of the Z-direction movement mechanism, the Z-direction movement block is installed on the Z-direction ball screw, and the Z-direction drive motor is installed on the Z-direction movement mechanism support frame.

Further, in the Z-axis motion mechanism, the transmission mechanism in the Z-axis direction can be realized by mechanisms such as ball screws and synchronous pulleys. Here, the ball screws are selected to realize the Z-direction movement of the 3D printing mechanism, and the ball screws are fixed on the Z axis. Shaft motion mechanism support frame. The lower end of the support frame of the Z-axis motion mechanism is equipped with a motor base, and the Z-axis motion mechanism is installed on the sun gear and the reinforcement ring through the motor base, and a planetary gear mechanism drive motor is installed on the motor base. A Z-axis motion drive motor is installed.

The feeding mechanism includes a feeding wheel and a supporting frame for the feeding wheel. There are at least two sets of feeding mechanisms. This example takes a dual-nozzle printer as an example. There are two sets of feeding mechanisms, namely: feeding wheel A, feeding wheel supporting frame A, feeding wheel B, and feeding wheel supporting frame B. Wherein, the feed wheel support frame is installed on the support frame of the Z-direction movement mechanism, and the feed wheel is installed on the feed wheel support frame.

Further, the feeding mechanism is installed on the supporting frame of the Z-axis motion mechanism, the supporting frame of the feeding wheel is fixed on the supporting frame of the Z-axis moving mechanism, and the feeding wheel is installed on the supporting frame of the feeding wheel.

The described cylindrical coordinate 3D printer capable of printing with multiple nozzles at the same time, wherein the precision planetary gear mechanism and the retractable cantilever beam mechanism respectively realize the movement in the polar angle direction and the polar axis direction of the polar coordinates, and jointly realize the polar coordinate plane The printing movement of the precision planetary gear mechanism, the retractable cantilever beam mechanism and the movement of the Z-direction movement mechanism together realize the printing work of the 3D printer according to the spatial cylindrical coordinates.

The described cylindrical coordinate 3D printer capable of printing multiple nozzles at the same time, the scalability of the structure is realized by adjusting the planetary gear, the telescopic cantilever beam mechanism and the Z-axis motion mechanism according to the actual size of the sun gear in the planetary gear mechanism. The number of nozzles can be changed to perform multi-nozzle printing or single-nozzle printing.

The cylindrical coordinate 3D printer that can realize simultaneous printing of multiple nozzles can realize multi-color printing when there are materials of different colors on the feeding wheel.

Compared with the existing 3D printers, a cylindrical coordinate 3D printer capable of simultaneously printing with multiple nozzles according to the present invention has the following characteristics:

(1) Simultaneous printing with multiple nozzles is possible to improve printing efficiency

(2) Scalability, according to the specific size of the planetary gear, the planetary gear, the Z-axis motion mechanism and the retractable cantilever beam mechanism can be added, thereby increasing the number of nozzles.

(3) When the feeding mechanism provides materials of different colors, multi-color printing can be realized.

(4) The running trajectory of the nozzle is calculated according to the spatial cylindrical coordinate system, the transmission error of the mechanism does not accumulate, the corresponding speed of the coordinate axes of the two polar coordinate systems is fast, and the printing efficiency is high.

(5) Because the trajectory is calculated in polar coordinates, compared with ordinary 3D printers, the 3D printer with this structure has a higher accuracy and faster speed of the curved trajectory, so this printing mechanism is very suitable for printing rotary types such as central axes. Component.

Description of drawings

The present invention will be further described below in conjunction with accompanying drawing:

Figure 1 is a schematic diagram of the overall structure of the 3D printer of the present invention.

Fig. 2 is a structural diagram of the planetary gear mechanism of the 3D printer of the present invention.

Fig. 3a is a schematic diagram 1 of the structure of the telescopic arm beam when printing with dual nozzles of the 3D printer of the present invention.

Fig. 3b is a schematic diagram 2 of the structure of the telescopic arm beam when printing with dual nozzles of the 3D printer of the present invention.

Fig. 4a is a schematic structural diagram a of the Z-axis motion mechanism and the feeding mechanism of the 3D printer of the present invention.

Fig. 4b is a structural diagram b of the Z-axis motion mechanism and the feeding mechanism of the 3D printer of the present invention.

Fig. 5 is a schematic diagram of the working trajectory of the nozzle during the printing operation of the 3D printer of the present invention.

Fig. 6 is a schematic diagram of the effective working area printed by the 3D printer of the present invention and the movement track of the transmission member.

Fig. 7 is a schematic diagram of the Archimedes spiral trajectory of the 3D printer of the present invention.

Drawing number identification: 1. External meshing precision planetary gear mechanism, 2. Telescopic arm beam mechanism, 3. Z-axis movement mechanism, 4. Feeding mechanism;

1-1, sun gear, 1-2A, planetary gear A, 1-2B, planetary gear B, 1-3, support block, 1-4, reinforcement ring, 1-5, disc-shaped workbench;

2-1A, nozzle A, 2-2A, feeding motor A, 2-3A, Z-direction movement block A, 2-4A, polar axial drive motor A, 2-5A, polar axial ball screw A, 2 -6A, limit block A;

2-1B, nozzle B, 2-2B, feeding motor B, 2-3B, Z direction movement block B, 2-4B, polar axial drive motor B, 2-5B, polar axial ball screw B, 2 -6B, limit block B;

3-1A, Z direction drive motor A, 3-2A, Z direction motion mechanism support frame A, 3-3A, Z direction ball screw A, 3-4A, planetary gear mechanism drive motor A, 3-5A, motor seat A, 3-1B, Z direction drive motor B, 3-2B, Z direction motion mechanism support frame B, 3-3B, Z direction ball screw B, 3-4B, planetary gear mechanism drive motor B, 3-5B) , motor base B;

4-1A, feeding wheel A, 4-2A, feeding wheel supporting frame A, 4-1B, feeding wheel B, 4-2B, feeding wheel supporting frame B.

detailed description

Below in conjunction with example and accompanying drawing, this technical scheme is further described:

Referring to the accompanying drawings 1 to 7, a cylindrical coordinate 3D printer capable of simultaneously printing with multiple nozzles includes an external meshing precision planetary gear mechanism (1), a retractable cantilever beam mechanism (2), a Z-axis motion mechanism (3), a power supply Feeding mechanism (4).

The external meshing precision planetary gear mechanism (1) consists of a sun gear (1-1), a planetary gear (1-2), a support block (1-3), a reinforcing ring (1-4) and a disc-shaped working Taiwan (1-5) constitutes. There are at least two planetary gears (1-2) described above. This example takes a double print head as an example, so there are two planetary gears, namely planetary gear A (1-2A) and planetary gear (1-2B). B (1-2B). Among them, the sun gear (1-1), the reinforcement ring (1-4) and the disc-shaped workbench (1-4) are fixed on the support block (1-3), the number of support blocks is arbitrary, and the number is preferred Choose an even number, and the distribution method should be evenly distributed on the equal points of the reinforcement ring. as shown in picture 2.

In the external meshing precision planetary gear mechanism, the planetary gear is installed on the output shaft of the driving motor of the external meshing precision planetary gear mechanism, and is externally meshed with the sun gear. Inside the external meshing precision planetary gear mechanism, there is also a reinforced ring that is concentric with the sun gear in the external meshing precision planet and on the same plane. There is a disc-shaped worktable inside the reinforced ring, and the disc-shaped working table The platform is concentric with the reinforced ring and the sun gear.

Further, in the external meshing precision planetary gear mechanism, the sun gear and the reinforcing ring are fixed in the slots on the support blocks below them, the number of support blocks is arbitrary, and the number is preferably an even number, and the distribution method should be evenly distributed among Reinforced at the bisecting point of the ring.

The telescopic cantilever beam mechanism (2) includes a nozzle (2-1), a feeding motor (2-2), a Z movement block (2-3), a polar axial drive motor (2-4), a polar axis toward the ball screw (2-5) and stop (2-6). There are at least two spray heads (2-1) in the telescopic cantilever beam mechanism (2). This example takes double nozzles as an example, so there are two sets of retractable cantilever beam structures, namely: nozzle A (2-1A), feeding motor A (2-2A), Z-direction movement block A (2-3A), Pole axial drive motor A (2-4A), pole axial ball screw A (2-5A), (2-6A) limit block A (2-6A),

Nozzle B (2-1B), feeding motor B (2-2B), Z-direction movement block B (2-3B), polar axial drive motor B (2-4B), polar axial ball screw B (2 -5B), limit block B (2-6B). The polar axial drive mode is selected as a ball screw, or a reasonable mechanism such as a worm gear, a synchronous belt, etc. can be selected. Among them, the polar axial ball screw (2-5) and the polar axial drive motor (2-4) are fixed on the Z-direction movement block (2-3), and the polar axial ball screw (2-5) One end is installed with the feeding drive motor (2-2) and the nozzle (2-1), and the other end has a limit block (2-6), which prevents the extreme axial movement from being over-formed, Avoid causing damage to the mechanism. As shown in accompanying drawing 3a, accompanying drawing 3b.

Further, in the retractable cantilever beam mechanism, the driving mode in the polar axis direction can be selected from various forms such as ball screw, worm gear and worm gear, and synchronous belt transmission mechanism, and the ball screw is selected here. The polar axial ball screw and the polar axial drive motor are fixed on the Z-direction movement block. A nozzle and a feeding motor are installed on one section of the polar axial ball screw, and a limit block is installed on the other end.

The Z-axis motion mechanism (3) includes a Z-direction drive motor (3-1), a Z-direction motion mechanism support frame (3-2), a Z-direction ball screw (3-3), a planetary gear drive motor (3 -4), motor seat (3-5). There are at least two sets of Z-axis motion mechanisms (3). This example takes the dual-nozzle printing mechanism as an example. There are two sets of Z-direction motion mechanisms, namely: Z-direction drive motor A (3-1A), Z-direction motion mechanism support frame A (3-2A), Z-direction ball screw A (3-3A), planetary gear drive motor A (3-4A), motor seat A (3-5A), Z-direction drive motor B (3-1B), Z-direction motion mechanism support frame B (3-2B ), Z-direction ball screw B (3-3B), planetary gear drive motor B (3-4B), motor base B (3-5B). Among them, the planetary gear drive motor (3-4) is fixed on the motor base (3-5), and the Z-axis movement device is installed on the sun gear (1-1) and the reinforcement ring (1-1) through the motor base (3-4). 4) In the above, the Z-direction drive mode is selected as a ball screw, or it can be selected as a synchronous belt drive and other feasible methods. The Z-direction ball screw (3-3) is fixed on the support frame (3-2) of the Z-direction movement mechanism , the Z-direction movement block (2-3) is installed on the Z-direction ball screw (3-3), and the Z-direction drive motor (3-1) is installed on the Z-direction movement mechanism support frame (3-2). Shown in Figure 4a and Figure 4b.

Further, in the Z-axis motion mechanism, the transmission mechanism in the Z-axis direction can be realized by mechanisms such as ball screws and synchronous pulleys. Here, the ball screws are selected to realize the Z-direction movement of the 3D printing mechanism, and the ball screws are fixed on the Z axis. Shaft motion mechanism support frame. The lower end of the support frame of the Z-axis motion mechanism is equipped with a motor base, and the Z-axis motion mechanism is installed on the sun gear and the reinforcement ring through the motor base, and a planetary gear mechanism drive motor is installed on the motor base. A Z-axis motion drive motor is installed.

The feeding mechanism (4) includes a feeding wheel (4-1) and a feeding wheel support frame (4-2). There are at least two sets of feeding mechanisms (4). This example takes a dual-nozzle printer as an example. There are two sets of feeding mechanisms, namely: (4-1A) feeding wheel A (4-1A), feeding wheel support frame A (4-2A), and feeding wheel B (4-1B), feed wheel support frame B (4-2B). Wherein, the feed wheel support frame (4-2) is installed on the support frame (3-2) of the Z-direction movement mechanism, and the feed wheel (4-1) is installed on the feed wheel support frame (4-2). As shown in Figure 4.

Further, the feeding mechanism is installed on the supporting frame of the Z-axis motion mechanism, the supporting frame of the feeding wheel is fixed on the supporting frame of the Z-axis moving mechanism, and the feeding wheel is installed on the supporting frame of the feeding wheel.

The described cylindrical coordinate 3D printer capable of printing with multiple nozzles at the same time, wherein the precision planetary gear mechanism and the retractable cantilever beam mechanism respectively realize the movement in the polar angle direction and the polar axis direction of the polar coordinates, and jointly realize the polar coordinate plane The printing movement of the precision planetary gear mechanism, the retractable cantilever beam mechanism and the movement of the Z-direction movement mechanism together realize the printing work of the 3D printer according to the spatial cylindrical coordinates.

The described cylindrical coordinate 3D printer capable of printing multiple nozzles at the same time, the scalability of the structure is realized by adjusting the planetary gear, the telescopic cantilever beam mechanism and the Z-axis motion mechanism according to the actual size of the sun gear in the planetary gear mechanism. The number of nozzles can be changed to perform multi-nozzle printing or single-nozzle printing.

The cylindrical coordinate 3D printer that can realize simultaneous printing of multiple nozzles can realize multi-color printing when there are materials of different colors on the feeding wheel.

In this example, the planetary gear (1-2) in the precision planetary gear mechanism (1) is driven by the planetary gear mechanism driving motor (3-5), realizing the rotation of the planetary gear mechanism and the revolution around the sun gear (1-1) , so as to realize the movement in the direction of polar angle in polar coordinates. In the retractable cantilever beam mechanism (2), the polar axial ball screw (2-5) is driven by the polar axial drive motor (2-4) to realize the movement in the polar axis direction in the polar coordinate system, so that the nozzle can achieve extreme The printing movement of the two-dimensional plane under the coordinate system; the Z-direction drive motor (3-1) drives the Z-direction ball screw (3-2) to rotate, and realizes the vertical movement of the Z-item motion block (2-3) in the Z direction. Drive the telescopic cantilever beam mechanism (2) to realize the movement in the Z-axis direction, and finally realize the three-dimensional movement of the sprinkler head in the space column coordinate system. The printing material is placed on the feeding mechanism (4), and the material is delivered to the nozzle (2-1) through the feeding motor (2-2), that is, the 3D printing work under the cylindrical coordinate system can be realized.

In this example, the operating principle diagram of the dual nozzles is shown in Figures 5 and 6. The nozzle A prints layer A, and the nozzle B prints layer B. The computer control system scans the two-layer data of the discrete model, and the first layer model data is loaded to the nozzle A. , the second layer of model data is loaded to nozzle B. Nozzle A prints first. When Nozzle A prints a part, Nozzle B starts to print the second layer, which realizes double-layer printing at the same time and improves printing efficiency. Theoretically, it is double the efficiency, but the actual efficiency is 1.5-1.8 times the efficiency, because nozzle B follows nozzle A to print, and there is a certain lag. According to the size of the sun gear, the number of nozzles can be increased to achieve printing with more than two nozzles, which can greatly improve the printing efficiency.

In this example, the calculation of the trajectory of the nozzle is based on the spatial cylindrical coordinate system, so the speed and accuracy of the printing curve are significantly improved compared with the ordinary structure of the printer. The structure of the printer is very suitable for making rotary parts such as shafts. Accompanying drawing 7 is the Archimedes spiral trajectory of the dual-jet printer in this example.

In this example, if the feeding wheel A and the feeding wheel B provide printing materials of different colors, two-color printing will be realized. On the basis of adding nozzles and adding feeding mechanism, multi-color printing can also be realized.

Claims (10)

1. A cylindrical coordinate 3D printer capable of simultaneously printing with multiple nozzles, characterized in that it includes an external meshing precision planetary gear mechanism, a retractable cantilever beam mechanism, a Z-axis motion mechanism, and a feeding mechanism; The external meshing precision planetary gear mechanism is composed of a sun gear, a planetary gear, a support block, a reinforced ring and a disc-shaped worktable, wherein the sun gear, the reinforced ring and the disc-shaped worktable are fixed on the support block, and the support The number of blocks is arbitrary, and the number is preferably an even number, and the distribution method should be evenly distributed on the equal points of the reinforcement ring; In the external meshing precision planetary gear mechanism, the planetary gear is installed on the output shaft of the driving motor of the external meshing precision planetary gear mechanism, and is externally meshed with the sun gear; inside the external meshing precision planetary gear mechanism, there is another sun gear that is in contact with the external meshing precision planetary gear It is a concentric reinforced ring on the same plane, and there is a disc-shaped worktable inside the reinforced ring, and the disc-shaped worktable is concentric with the reinforced ring and the sun gear; The telescopic cantilever beam mechanism includes a nozzle, a feeding motor, a Z motion block, a polar axial drive motor, a polar axial ball screw and a limit block, wherein the polar axial ball screw and the polar axial drive motor are fixed On the Z-direction movement block, the feeding drive motor and the nozzle are installed at one end of the polar axial ball screw, and there is a limit block at the other end. Damage; the polar axial ball screw and the polar axial drive motor are fixed on the Z-direction movement block, and a nozzle and a feeding motor are installed on one end of the polar axial ball screw, and a limit block is installed on the other end; The Z-axis motion mechanism includes a Z-direction drive motor, a Z-direction motion mechanism support frame, a Z-direction ball screw, a planetary gear drive motor and a motor seat, wherein the planetary gear drive motor is fixed on the motor seat, and the Z-axis motion device passes through The motor seat is installed on the sun gear and the reinforced ring, the Z-direction ball screw is fixed on the support frame of the Z-direction movement mechanism, the Z-direction movement block is installed on the Z-direction ball screw, and the Z-direction drive motor is installed on the Z-direction movement mechanism above the support frame; The feeding mechanism includes a feeding wheel and a feeding wheel support frame; the feeding mechanism is installed on the Z-axis motion mechanism support frame, wherein the feed wheel support frame is installed on the Z-direction motion mechanism support frame, and the feed wheel is installed On top of the feed wheel support bracket. 2. A cylindrical coordinate 3D printer capable of simultaneous printing with multiple nozzles according to claim 1, wherein there are at least two planetary gears in the planetary gear mechanism. 3. A cylindrical coordinate 3D printer capable of multi-nozzle simultaneous printing according to claim 1, characterized in that: in the external meshing precision planetary gear mechanism, the sun gear and the reinforcing ring are fixed on the support block below them The number of support blocks in the card slot is arbitrary, and the number is preferably an even number, and the distribution method should be evenly distributed on the equal points of the reinforcement ring. 4. A cylindrical coordinate 3D printer capable of simultaneous printing with multiple nozzles according to claim 1, characterized in that there are at least two nozzles in the retractable cantilever beam mechanism. 5. A cylindrical coordinate 3D printer capable of simultaneous printing with multiple nozzles according to claim 1, characterized in that: the polar axial drive mode in the telescopic cantilever beam mechanism is selected as a ball screw, and also It can be realized by worm gear and worm gear and synchronous belt transmission mechanism. 6. A cylindrical coordinate 3D printer capable of simultaneous printing with multiple nozzles according to claim 1, characterized in that: there are at least two sets of Z-axis motion mechanisms; in the Z-axis motion mechanism, the transmission in the Z-axis direction The mechanism can be realized by ball screw and synchronous pulley mechanism. 7. A cylindrical coordinate 3D printer capable of simultaneous printing with multiple nozzles according to claim 1, characterized in that there are at least two sets of feeding mechanisms. 8. A cylindrical coordinate 3D printer capable of simultaneous printing with multiple nozzles according to claim 1, characterized in that: the precision planetary gear mechanism and the retractable cantilever beam mechanism respectively realize the polar angle direction and the polar axis of the polar coordinates The movement in the direction of the polar coordinates together realizes the printing movement of the polar coordinate plane; the movement of the precision planetary gear mechanism, the retractable cantilever beam mechanism and the movement mechanism in the Z direction jointly realizes the printing work of the 3D printer according to the spatial cylindrical coordinates. 9. A cylindrical coordinate type 3D printer capable of multi-nozzle simultaneous printing according to claim 1, characterized in that: the cylindrical coordinate type 3D printer capable of multi-nozzle simultaneous printing, according to the planetary gear mechanism The actual size of the middle sun gear adjusts the planetary gear, the telescopic cantilever beam mechanism and the Z-axis movement mechanism to realize the change of the number of nozzles, and to perform multi-nozzle printing or single-nozzle printing. 10. A cylindrical coordinate 3D printer capable of simultaneous printing of multiple nozzles according to claim 1, characterized in that: the cylindrical coordinate 3D printer capable of simultaneous printing of multiple nozzles, when the feed wheel Multi-color printing is possible when there are materials of different colors on it.