Multi-color 3D printing system and 3D printing method therefor

Abstract

Disclosed in the present application are a multi-color 3D printing system and a 3D printing method therefor. The multi-color 3D printing system comprises: a 3D printer having no less than two print heads, wherein each print head has an extruder, and the print heads include a first print head and a second print head; at least one material bin connected to the print heads, which material bin stores materials for 3D printing; material channels connecting the print heads and the material bin; and a control unit for controlling printing, which is configured to control the multi-color 3D printing system to perform a material changing action, wherein a plurality of parallel channels corresponding to and connected to the material bin are provided at the ends of the material channels close to the material bin, the parallel channels have hollow cavities for filaments of the materials to pass through, and the parallel channels are provided with material feeding and retracting mechanisms corresponding to the material bin and connected to the parallel channels.

Description

Multi-color 3D printing system and 3D printing method thereof TECHNICAL FIELD

[0001] The present application relates to the field of 3D printing, in particular to a multi-color 3D printing system and a 3D printing method thereof. BACKGROUND

[0002] The mainstream multi-color 3D printer in the market at present mainly obtains multi-color printing effect by supplying a single-head 3D printer with multiple different colors of material. The implementation of this scheme needs to switch different materials during printing, which has the disadvantages of long switching waiting time and waste of material. In order to improve the printing efficiency and save material, it has obvious advantages to configure a material box with different color materials to each printing head of a multi-head printer. When the first printing head is in a printing state and the second printing head is connected with the next sequence of material, the next sequence of material is fed to the second printing head and the second printing head is in a standby printing state under the condition that the first printing head is in a printing state. In addition, when the system obtains that the first printing head is in a printing state and is connected with the current sequence of material and the next sequence of material at the same time, the material switching action can be completed by feeding the next sequence of material to the first printing head to extrude the current sequence of material. Users have strong demand for 3D printers with high printing efficiency, multi-material compatibility, environmental friendliness, intelligence and ease of use.

[0003] There is a need in the art to develop an improved, faster, more reliable and stable multi-color 3D printer to alleviate or overcome the drawbacks of the prior art and to obtain other beneficial technical effects.

[0004] The information included in this Background section of the specification, including any references cited herein and any description or discussion thereof, is included for technical reference purposes only and is not to be construed as subject matter by which the scope of the application is to be limited. SUMMARY

[0005] The present application is proposed in view of the above and other more ideas.

[0006] According to one idea of the present application, a multi-color 3D printing system is proposed, which comprises:

[0007] a 3D printer with no less than two printing heads, the printing heads having extruders, the printing heads including a first printing head and a second printing head;

[0008] at least one material bin connected with the printing heads, the material bin storing material for 3D printing;

[0009] a material channel connecting the printing heads and the material bin; and

[0010] a control unit for controlling printing, the control unit configured to control the multi-color 3D printing system to perform a material changing action;

[0011] The material channel is provided with a plurality of parallel channels corresponding to the material bin and connected to the material bin. The parallel channels have hollow cavities for the filament of the material to pass through. The parallel channels are provided with a feeding and withdrawing mechanism corresponding to the material bin and connected to the parallel channels.

[0012] In one embodiment, the multi-color 3D printing system further comprises a material management unit configured to obtain a material bin where a current sequence of material is located, and obtain a material bin where a next sequence of material is located.

[0013] In one embodiment, the control unit determines whether the current sequence of material and the next sequence of material are connected to the same print head.

[0014] In one embodiment, when the control unit determines that the current sequence of material and the next sequence of material are connected to the same print head, the control unit controls the multi-color 3D printing system to perform a first material changing action,

[0015] The first material changing action comprises:

[0016] The control unit controls the feeding and withdrawing mechanism to withdraw the current sequence of material,

[0017] controls the feeding and withdrawing mechanism to feed the next sequence of material, the next sequence of material entering the print head through one of the parallel channels and extruding the remaining part of the current sequence of material from the extruder,

[0018] controls the multi-color 3D printing system to heat the next sequence of material to a molten state to enter a ready-to-print state,

[0019] controls the print head to start printing.

[0020] In one embodiment, when the control unit determines that the current sequence of material and the next sequence of material are connected to different print heads, the control unit controls the multi-color 3D printing system to perform a second material changing action,

[0021] The second material changing action comprises:

[0022] While the first print head is printing the current sequence of material, the control unit controls the feeding and withdrawing mechanism to feed the next sequence of material to the second print head, the next sequence of material entering the second print head through one of the parallel channels corresponding to the second print head,

[0023] the control unit controls the multi-color 3D printing system to heat the next sequence of material to a molten state into a ready-to-print state,

[0024] the control unit controls the first print head to stop printing and return to a home position, and controls the second print head to start printing.

[0025] In one embodiment, when the material management unit obtains that the next sequence of material is located in a material bin connected to the first print head that prints the current sequence of material and a material bin connected to the second print head, the control unit controls the material feeding and withdrawing mechanism to feed the next sequence of material to the second print head, the next sequence of material enters the second print head through one of the parallel channels corresponding to the second print head.

[0026] In one embodiment, at least one of the material bins constitutes a material cartridge module, and each of the print heads corresponds to one of the material cartridge modules.

[0027] In one embodiment, the control unit obtains the color of the next sequence of material through slicing software and determines the material bin where the next sequence of material is located.

[0028] In one embodiment, the end of the material channel close to the print head has a multi-in-one channel formed by the plurality of parallel channels converging, and the multi-in-one channel is connected to the print head.

[0029] According to another concept of the present application, a 3D printing method for a multi-color 3D printing system is provided, the multi-color 3D printing system comprising no less than two print heads, the print heads comprising a first print head and a second print head; at least one material bin connected to the print heads, the material bin storing material for 3D printing; a material channel connecting the print heads and the material bin; and a control unit for controlling printing, the control unit being configured to control the multi-color 3D printing system to perform a material changing action, the 3D printing method comprising:

[0030] a material management unit obtaining a material bin where a current sequence of material is located,

[0031] the material management unit obtaining a material bin where a next sequence of material is located, and

[0032] the control unit determining whether the current sequence of material and the next sequence of material are connected to the same print head.

[0033] In one embodiment, the 3D printing method further comprises:

[0034] when the control unit determines that the current sequence of material and the next sequence of material are connected to the same print head, the control unit controls the multi-color 3D printing system to perform a first material changing action,

[0035] The first material changing action comprises:

[0036] The control unit controls the feeding and withdrawing mechanism to withdraw the current sequence of material,

[0037] controls the feeding and withdrawing mechanism to feed the next sequence of material,

[0038] controls the multi-color 3D printing system to heat the next sequence of material to a molten state into a ready-to-print state,

[0039] controls the printing head to start printing.

[0040] In one embodiment, the 3D printing method further comprises:

[0041] When the control unit determines that the current sequence of material and the next sequence of material are connected to different printing heads,

[0042] the control unit controls the multi-color 3D printing system to perform a second material changing action,

[0043] The second material changing action comprises:

[0044] While the first printing head is printing the current sequence of material, the control unit controls the feeding and withdrawing mechanism to feed the next sequence of material to the second printing head,

[0045] the control unit controls the multi-color 3D printing system to heat the next sequence of material to a molten state into a ready-to-print state,

[0046] the control unit controls the first printing head to stop printing and return to the home position, and controls the second printing head to start printing.

[0047] In one embodiment, the 3D printing method further comprises:

[0048] When the material management unit obtains that the next sequence of material is located in a material bin connected to the first printing head printing the current sequence of material and a material bin connected to the second printing head respectively, the control unit controls the feeding and withdrawing mechanism to feed the next sequence of material to the second printing head.

[0049] Further embodiments of the present application can also achieve other advantageous technical effects not listed one by one, which are partially described below and can be expected and understood by those skilled in the art after reading the present application. BRIEF DESCRIPTION OF DRAWINGS

[0050] The above features and advantages and other features and advantages of the embodiments are readily apparent from the following description, taken in connection with the accompanying drawings, from the claims, and from the appended description of the embodiments presented by way of illustration and by way of example. The embodiments will be described with respect to these drawings in which the following is shown:

[0051] FIG. 1 is a schematic diagram of a multi-color 3D printing system of the present application; and

[0052] FIG. 2 is a flowchart of a first and second material changing action of the multi-color 3D printing system of the present application. DETAILED DESCRIPTION

[0053] The details of one or more embodiments of the application are set forth in the accompanying description below, and in part in the drawings. Other features, objects, and advantages of the application will be apparent from the description and drawings, and from the claims.

[0054] It should be understood that the embodiments illustrated and described are not intended to be limited to the details shown, and thus they are presented for illustrative purposes only. Embodiments illustrated and described can be implemented in various ways without departing from the scope or spirit of the present disclosure. Embodiments are presented by way of example only and various modifications and variations can be made to these embodiments by those skilled in the art without departing from the spirit or scope of the disclosure. For example, features illustrated or described as part of one embodiment can be used with another embodiment to yield still a further embodiment. Thus, it is intended that the present disclosure encompass such modifications and variations as come within the scope of the appended claims and their equivalents.

[0055] Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and not of limitation. The use of terms "including," "comprising," or "having" and variations thereof herein is intended to be open-ended, and includes the presence of zero, one or more of items so far as are encompassed by the terms.

[0056] The term "3D printer" not only includes three-dimensional printing devices in the general sense of the art, such as industrial grade 3D printers, including consumer grade 3D printers, but also laser processing devices with 3D printing function, and 3D printing devices with laser processing function, are all within the scope of "3D printer" of the present application.

[0057] As used herein, the terms "first", "second", and the like, are used only for descriptive purposes and do not imply or suggest relative importance or imply the number of the indicated technical features. Thus, the features defined with "first", "second", etc. can explicitly or implicitly include one or more of the features. In this document, the meaning of "a plurality" is two or more, unless there is a clear specific limitation.

[0058] As used herein, the terms "mount", "connect", "connection", "fixed", and the like should be understood in a broad sense unless otherwise indicated, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in this paper can be understood according to the specific circumstances.

[0059] The application will be described in more detail below with reference to specific embodiments of the application.

[0060] 3D printer

[0061] The 3D printer has a printing platform or a printing table. The printing platform theoretically defines an x-y plane, which is defined by an x-axis and a y-axis. Among them, the x-axis, the y-axis and the z-axis are perpendicular to each other. The term "motion along the axis", such as motion along the x-axis, y-axis or z-axis, means motion parallel to the axis or in the same straight line as the axis. In this paper, the orientation specified by the x-axis, y-axis or z-axis is only for convenience of discussion and does not constitute any limitation on the orientation. Of course, those skilled in the art can also conceive that the printing platform can be connected with the x-axis, y-axis or z-axis motion module, and this paper does not limit it. In addition, the printing platform has a heating function, which can be a whole piece of plate or composed of multiple layers of plate material in a detachable or non-detachable manner. The printing platform of the 3D printer can be used to place the material to be printed, the printing object, etc. The printing platform provides a flat working plane as much as possible. The printing platform defines the movement range of the printing nozzle.

[0062] The 3D printer can be provided with x-axis, y-axis and z-axis motion modules, a printing platform and drive motors corresponding to the x-axis, y-axis and z-axis motion modules. Among them, for example, the x-axis, y-axis motion module (generally with or including a drive motor or actuator) can be operatively connected with the printing head, and the movement of the printing head along the x-axis and y-axis can be controlled. The z-axis motion module (generally with or including a drive motor or actuator) can be connected with the printing platform to control the movement of the printing platform along the z-axis direction. Of course, the 3D printer of the present application is not limited to this setting, for example, the printing head can also be connected with the x-axis, y-axis and z-axis motion modules.

[0063] Multi-color 3D printing system

[0064] The multi-color 3D printing system is a system for controlling a 3D printer to perform multi-color printing, which comprises a 3D printer and a material replacement module or a cartridge module for storing printing materials.

[0065] Specifically, FIG. 1 shows a multi-color 3D printing system S, which comprises: a 3D printer with no less than two printing heads 10A, 10B, the printing heads 10A, 10B having extruders 101, the printing heads including a first printing head 10A and a second printing head 10B; at least one cartridge 11 connected with the printing heads 10A, 10B, the cartridge 11 storing material for 3D printing, the at least one cartridge 11 constituting a cartridge module 11A, each printing head 10A, 10B corresponding to one cartridge module 11A; a material channel 12 connecting the printing heads 10A, 10B and the cartridge 11; and a control unit 13 for controlling printing, the control unit 13 being configured to control the multi-color 3D printing system S to perform a material changing action. The control unit 13 can include a master control chip, or can be other units with control functions.

[0066] As shown in FIG. 1, the material channel 12 has a plurality of parallel channels 121 corresponding to the cartridge 11 and connected with the cartridge 11 at one end close to the cartridge 11, the parallel channels 121 having hollow cavities 1211 for the filaments of the material to pass through, and the parallel channels 121 are provided with a feeding and withdrawing mechanism 122 corresponding to the cartridge 11 and connected with the parallel channels 121. The material channel 12 has a multi-in-one channel 1212 at one end close to the printing heads 10A, 10B, the multi-in-one channel 1212 being formed by the plurality of parallel channels 121 converging together, and the multi-in-one channel 1212 being connected with the printing heads 10A, 10B. The plurality of parallel channels 121 form a parallel structure with each other, and at the one end close to the printing heads 10A, 10B, the plurality of parallel channels 121 are connected together and converge to form one multi-in-one channel 1212.

[0067] As shown in FIG. 1, the multi-color 3D printing system S further comprises a material management unit 14, the material management unit 14 being configured to obtain the cartridge 11 where the current sequence of material is located, and obtain the cartridge 11 where the next sequence of material is located. The control unit 13 is configured to determine whether the current sequence of material and the next sequence of material are connected to the same printing head 10A or 10B. The control unit 13 obtains the material color of the next printing sequence through the slicing software and determines the cartridge 11 where the next sequence of material is located. Among them, the current sequence of material represents the sequence of material that the 3D printer is currently printing, and the next sequence of material represents the next sequence of material that the control unit or the slicing software of the 3D printer obtains that the 3D printer will print. The current sequence of material and the next sequence of material can be different color sequences of material.

[0068] The material management unit 14 can be disposed in the material bin or partially disposed in the material bin. The material management unit 14 can be composed of software and hardware, or can be composed of software or hardware alone. The material management unit 14 refers to a software and / or hardware unit that can acquire the color, number or information of the material, and determine the connection state of the material. The material management unit 14 can perform material management by manually inputting the color, number or information of the material into the system by human. Alternatively, the material management unit 14 can be performed in an automated manner, for example, the color, number or information of the material can be automatically acquired and input into the system.

[0069] Generally, the material bin can store the material, and the material is placed in the material bin in the form of a roll. The material management unit 14 can acquire the color corresponding to the material roll and input the specific color into the control unit. Of course, the material bin here is not necessarily a bin structure, but can be any closed, open or semi-closed device suitable for storing or placing the material.

[0070] Embodiment 1 - Serial material changing action

[0071] When the control unit 13 determines that the current sequence material and the next sequence material are connected to the same print head 10A or 10B, the control unit 13 controls the multi-color 3D printing system S to perform a first material changing action, which is a serial material changing action. The serial material changing action means that only material switching is performed in 3D printing, and no print head switching is performed.

[0072] As shown in FIG. 2, the first material changing action includes:

[0073] S1. The control unit 13 controls the feeding and withdrawing mechanism 122 to withdraw the current sequence material,

[0074] S2. The control unit 13 controls the feeding and withdrawing mechanism 122 to feed the next sequence material, the next sequence material enters the multi-in-one channel 1212 through one of the parallel channels 121 and extrudes the remaining part of the current sequence material from the extruder 101,

[0075] S3. The control unit 13 controls the multi-color 3D printing system S to heat the next sequence material to a molten state to enter a printing-ready state, and

[0076] S4. The control unit 13 controls the print head 10A or 10B to start printing the next sequence material.

[0077] Specifically, in the embodiment 1, the current sequence material can be white material, and the next sequence material can be red material. The control unit 13 controls the first print head 10A to print the current sequence material, i.e. white material. The control unit 13 obtains the color of the next sequence material, i.e. red, through the slicing software. Then the material management unit 14 determines the position of the material bin 11 where the next sequence material is located, and the control unit 13 determines whether the current sequence material and the next sequence material are connected to the same print head 10A or 10B, if yes, the control unit 13 calls the first material changing action to perform the serial material changing. During the serial material changing, the current sequence material, i.e. white material, needs to be first withdrawn, and during the material withdrawal, part of the white material in the extruder will still stay in the extruder due to being in the molten state. After the material withdrawal is completed, the next sequence material is fed to the first print head 10A, and the next sequence material can push the remaining white material out during the feeding. Then the control unit 13 heats the next sequence material to the molten state, and controls the first print head 10A to start printing the next sequence material.

[0078] Such serial material changing needs to stop the print head in printing, and perform material withdrawal, feeding, washing and heating, and the print head needs to wait for a long time. However, by configuring multiple material bins for the print head, the multi-color printing function of the printer can be expanded.

[0079] Embodiment 2 - parallel material changing action

[0080] When the control unit 13 determines that the current sequence material and the next sequence material are connected to different print heads 10A, 10B, the control unit 13 controls the multi-color 3D printing system S to perform the second material changing action, which is a parallel material changing action. The parallel material changing action means that the material switching is performed in 3D printing, and the print head switching is also performed.

[0081] As shown in FIG. 2, the second material changing action includes:

[0082] S1. When the first print head 10A is printing the current sequence material, the control unit 13 controls the feeding and withdrawing mechanism 122 to feed the next sequence material to the second print head 10B, the next sequence material enters the multi-in-one channel 1212 through one of the parallel channels 121 corresponding to the second print head 10B, and then enters the second print head 10B,

[0083] S2. The control unit 13 controls the multi-color 3D printing system S to heat the next sequence material to the molten state to enter the printing-ready state,

[0084] S3. The control unit 13 controls the first print head 10A to stop printing and return to the home position, and controls the second print head 10B to start printing.

[0085] Specifically, in the embodiment 2, the current sequence material can be white material, and the next sequence material can be red material. The control unit 13 controls the first print head 10A to print the current sequence material, i.e. white material. The control unit 13 obtains the color of the next sequence material, i.e. red, through the slicing software. Then the material management unit 14 determines the position of the material bin 11 where the next sequence material is located, and the control unit 13 determines whether the current sequence material and the next sequence material are connected to the same print head 10A or 10B. If not, the control unit 13 calls the second material changing action to perform parallel material changing. During the parallel material changing, the first print head 10A continues to print the current sequence material. The control unit 13 controls the feeding and withdrawing mechanism 122 to feed the next sequence material to the second print head 10B. After the feeding is completed, the control unit 13 controls the multi-color 3D printing system S to heat the next sequence material to a molten state to enter the printing-ready state. Then, the control unit 13 controls the first print head 10A to stop printing and return to the home position, and controls the second print head 10B to start printing the next sequence material.

[0086] Such parallel material changing does not need to stop the printing head in printing to perform early material changing, has high printing efficiency, and does not need to wash the material, so that the material is not wasted significantly.

[0087] Embodiment 3 - Selection of serial-parallel scheme

[0088] When the material management unit 14 obtains that the next sequence material is located in the material bin 11 connected to the first print head 10A printing the current sequence material and the material bin 11 connected to the second print head 10B, the control unit 13 controls the feeding and withdrawing mechanism 122 to feed the next sequence material to the second print head 10B. The next sequence material enters the multi-in-one channel 1212 through one of the parallel channels 121 corresponding to the second print head 10B, and then enters the second print head 10B.

[0089] Specifically, in the embodiment 3, the current sequence material can be white material, and the next sequence material can be red material, and the first print head 10A prints the white material. When the material management unit 14 obtains that the position of the next sequence material in the multi-color 3D printing system S has multiple cases (one is located in the material bin 11 connected to the first print head 10A printing the current sequence material, and the other is located in the material bin 11 connected to the second print head 10B), the control unit 13 preferentially performs the second material changing action, and controls the feeding and withdrawing mechanism 122 to feed the next sequence material to the second print head 10B.

[0090] The foregoing description of several embodiments of the application has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to be limited to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teachings. The scope of the application is to be given by the appended claims, along with equivalents thereof.

Claims

1. A multi-color 3D printing system, characterized by, The multi-color 3D printing system comprises: a 3D printer with no less than two printing heads, the printing heads having extruders, the printing heads including a first printing head and a second printing head; at least one material bin connected with the printing heads, the material bin storing material for 3D printing; a material channel connecting the printing heads and the material bin; and a control unit for controlling printing, the control unit being configured to control the multi-color 3D printing system to perform a material changing action; wherein one end of the material channel close to the material bin has a plurality of parallel channels corresponding to the material bin and connected with the material bin, the parallel channels having hollow cavities for the filament of the material to pass through, and the parallel channels being provided with a material feeding and withdrawing mechanism corresponding to the material bin and connected with the parallel channels.

2. The multi-color 3D printing system of claim 1, wherein, The multi-color 3D printing system further comprises a material management unit, the material management unit being configured to obtain the material bin where the current sequence of material is located and obtain the material bin where the next sequence of material is located.

3. The multi-color 3D printing system of claim 2, wherein, The control unit determines whether the current sequence of material and the next sequence of material are connected to the same printing head.

4. The multi-color 3D printing system of claim 3, wherein, When the control unit determines that the current sequence of material and the next sequence of material are connected to the same printing head, the control unit controls the multi-color 3D printing system to perform a first material changing action, The first material changing action comprises: the control unit controls the material feeding and withdrawing mechanism to withdraw the current sequence of material, controls the material feeding and withdrawing mechanism to feed the next sequence of material, the next sequence of material entering the printing head through one of the parallel channels and extruding the remaining part of the current sequence of material from the extruder, controls the multi-color 3D printing system to heat the next sequence of material to a molten state into a ready-to-print state, controls the printing head to start printing.

5. The multi-color 3D printing system of claim 3, wherein, When the control unit determines that the current sequence of material and the next sequence of material are connected to different printing heads, the control unit controls the multi-color 3D printing system to perform a second material changing action, The second material changing action comprises: while the first printing head is printing the current sequence of material, the control unit controls the material feeding and withdrawing mechanism to feed the next sequence of material to the second printing head, the next sequence of material entering the second printing head through one of the parallel channels corresponding to the second printing head, the control unit controls the multi-color 3D printing system to heat the next sequence of material to a molten state into a ready-to-print state, the control unit controls the first printing head to stop printing and return to the original position, and controls the second printing head to start printing.

6. The multi-color 3D printing system according to claim 4 or 5, characterized in that When the material management unit obtains that the next sequence of material is located in the material bin connected with the first printing head printing the current sequence of material and the material bin connected with the second printing head respectively, the control unit controls the material feeding and withdrawing mechanism to feed the next sequence of material to the second printing head, the next sequence of material entering the second printing head through one of the parallel channels corresponding to the second printing head.

7. The multi-color 3D printing system according to any one of claims 1-5, wherein, One end of the material channel close to the printing heads has a multi-in-one channel gathered from the plurality of parallel channels, the multi-in-one channel being connected with the printing heads.

8. A 3D printing method for a multi-color 3D printing system, characterized in that, The multi-color 3D printing system comprises no less than two printing heads, the printing heads comprising a first printing head and a second printing head; at least one material bin connected with the printing heads, the material bin storing material for 3D printing; a material channel connecting the printing heads and the material bin; and a control unit for controlling printing, the control unit being configured to control the multi-color 3D printing system to perform a material changing action, the 3D printing method comprising: the material management unit obtaining a material bin where a current sequence of material is located, the material management unit obtaining a material bin where a next sequence of material is located, and the control unit determining whether the current sequence of material and the next sequence of material are connected to the same printing head.

9. The 3D printing method according to claim 8, characterized in that, comprising: when the control unit determines that the current sequence of material and the next sequence of material are connected to the same printing head, the control unit controls the multi-color 3D printing system to perform a first material changing action, the first material changing action comprising: the control unit controls the material feeding and withdrawing mechanism to feed the current sequence of material, controls the material feeding and withdrawing mechanism to feed the next sequence of material, controls the multi-color 3D printing system to heat the next sequence of material to a molten state into a ready-to-print state, controls the printing head to start printing.

10. The 3D printing method according to claim 9, characterized in that, when the control unit determines that the current sequence of material and the next sequence of material are connected to different printing heads, the control unit controls the multi-color 3D printing system to perform a second material changing action, the second material changing action comprising: while the first printing head is printing the current sequence of material, the control unit controls the material feeding and withdrawing mechanism to feed the next sequence of material to the second printing head, the control unit controls the multi-color 3D printing system to heat the next sequence of material to a molten state into a ready-to-print state, the control unit controls the first printing head to stop printing and return to the home position, and controls the second printing head to start printing.

11. The 3D printing method according to claim 9 or 10, characterized in that, when the material management unit obtains that the next sequence of material is located in a material bin connected with the first printing head printing the current sequence of material and a material bin connected with the second printing head respectively, the control unit controls the material feeding and withdrawing mechanism to feed the next sequence of material to the second printing head.

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