A 3D printing method

Abstract

The 3D printing method provided by the application comprises the following steps: S1. obtaining three-dimensional model data of a product; S2. dividing the three-dimensional model data in S1 into slices suitable for printing by a single-color 3D printer according to the thickness direction; S3. before starting printing, calculating the required wire length of different colors according to the color distribution of each slice in S2, and optimizing the printing path; S4. cutting the wires of different colors according to the wire length in S3, and connecting them into one to obtain a multi-color wire; S5. putting the multi-color wire into the wire conveying mechanism of the single-color 3D printer, opening the single-color nozzle, and making it move along the printing path optimized in step S3 to complete 3D printing; the method can realize multi-color 3D printing by reasonably planning the prepared multi-color wire and cooperating with the single-color nozzle, without changing the structure of the existing single-color 3D printer, and is suitable for a wide range, low in cost, and easy to popularize.

Description

Technical Field

[0001] This invention belongs to the field of 3D printing technology, specifically relating to a 3D printing method that achieves multi-color printing using an existing monochrome 3D printer. Background Technology

[0002] 3D printing, also known as additive manufacturing, is a technology that creates three-dimensional products by stacking materials layer by layer. Common 3D printers are monochrome. These printers mostly include monochrome nozzles, filament delivery mechanisms, nozzle wiping units, and other structures. When printing multi-color three-dimensional products, it is necessary to frequently pause to change different colors of filament. The operation is complicated, time-consuming, and labor-intensive, and it is difficult to achieve multiple colors in the same layer, thus limiting its applicability.

[0003] To address this issue, technical solutions have emerged in the market that use multiple filament delivery mechanisms to feed filaments of various colors. For example, Chinese patents CN106891521A and CN218315269U disclose such 3D printers. The former sets multiple filament delivery mechanisms on a rotating wheel, using rotation to supply different colored filaments to a single-color nozzle to achieve multi-color printing. The latter achieves multi-color printing through multiple single-color nozzles corresponding to multiple filament delivery mechanisms. However, both solutions require hardware modifications to existing single-color 3D printers, which are costly, result in complex structures, and are difficult to maintain. Furthermore, neither solution incorporates a color feedback system, making it difficult to determine whether the current printed color matches the actual requirements during automatic printing, thus hindering automatic adjustment. Summary of the Invention

[0004] The purpose of this invention is to overcome one or more drawbacks in the prior art and provide a 3D printing method for achieving multi-color printing using an existing monochrome 3D printer.

[0005] To achieve the above objectives, the technical solution adopted by this invention is a 3D printing method, comprising the following steps: S1. Obtain the 3D model data of the product; S2. Divide the 3D model data in S1 into slices suitable for monochrome 3D printers according to the thickness direction; S3. Before printing begins, calculate the required wire length for each color based on the color distribution of each slice in S2, and optimize the printing path; S4. Cut wires of different colors according to the wire length in S3, and connect them together to obtain multi-colored wires; S5. Place the multi-color filament into the filament feed mechanism of the monochrome 3D printer, turn on the monochrome nozzle, and move it along the printing path optimized in step S3 to complete the 3D printing.

[0006] Preferably, in step S3, if the color of the wire is the same as the color in the slice, the length of the wire of that color needs to be included with a margin, and the margin is divided into two parts and set at both ends of the wire of that color.

[0007] Preferably, in step S3, if the color of all the wires cannot match the color in the slice, a method of mixing multiple short wires of different colors is used, and the consistency of the colors after mixing is used as the basis when calculating the length of these short wires.

[0008] More preferably, in step S5, when printing to the junction of the two colors, the single-color printhead is subjected to color-changing rinsing or color-changing cleaning.

[0009] More preferably, step S5 further includes a step of color recognition of the monochrome nozzle outlet, which is achieved by an added visual acquisition unit.

[0010] More preferably, the color recognition step includes image grayscale conversion, color space conversion, and feature threshold comparison. If the comparison result exceeds the set range, printing is paused and an alarm is triggered.

[0011] More preferably, step S5 also dynamically adjusts the time of color-changing rinsing or color-changing cleaning based on the color recognition results to reduce losses.

[0012] More preferably, the visual acquisition unit includes a camera that moves with the monochrome nozzle.

[0013] Furthermore, the optimized printing path in step S3 is a single path from the starting point to the ending point, and the monochrome printhead in step S5 does not pause during the movement.

[0014] Furthermore, the optimized printing path in step S3 consists of multiple paths from the starting point to the ending point, with each path corresponding to a color. During the movement, if the color at the current position is the same as the corresponding color, printing is performed at the set speed; if the color at the current position is different from the corresponding color, extrusion is paused and the process proceeds quickly.

[0015] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art: The 3D printing method provided by this invention includes the following steps: S1. Obtaining the three-dimensional model data of the product; S2. Dividing the three-dimensional model data in S1 into slices suitable for printing with a monochrome 3D printer according to the thickness direction; S3. Before starting printing, calculating the required filament length for different colors based on the color distribution of each slice in S2, and optimizing the printing path; S4. Cutting filaments of different colors according to the filament lengths in S3, and connecting them together to obtain multi-color filaments; S5. Placing the multi-color filaments into the filament delivery mechanism of the monochrome 3D printer, turning on the monochrome nozzle, and moving it along the printing path optimized in step S3 to complete 3D printing; This method can achieve multi-color 3D printing by reasonably planning the prepared multi-color filaments in conjunction with the monochrome nozzle, without changing the existing monochrome 3D printer structure, and has a wide range of applications, low cost, and is easy to promote. Attached Figure Description

[0016] Figure 1 This is a diagram of the multi-color wire structure corresponding to a single slice in one embodiment of the present invention.

[0017] Figure 2 This is a diagram of the multi-color wire structure corresponding to a single slice in another embodiment of the present invention.

[0018] Figure 3 This is _color_schedule.csv generated by another embodiment of the present invention.

[0019] Figure 4 This is _color_schedule.csv generated by another embodiment of the present invention.

[0020] Wherein: 10. First color; 20. Second color; 30. Third color; 40. Balance. Detailed Implementation

[0021] The 3D printing method provided by this invention includes the following steps: S1. Obtain the 3D model data of the product; S2. Divide the 3D model data in S1 into slices suitable for monochrome 3D printers according to the thickness direction; S3. Before printing begins, calculate the required wire length for each color based on the color distribution of each slice in S2, and optimize the printing path; S4. Cut wires of different colors according to the wire length in S3, and connect them together to obtain multi-colored wires; S5. Place the multi-color filament into the filament feed mechanism of the monochrome 3D printer, turn on the monochrome nozzle, and move it along the printing path optimized in step S3 to complete the 3D printing.

[0022] This method can achieve multi-color 3D printing by rationally planning and preparing multi-color filaments and combining them with single-color nozzles. It does not require changes to the structure of existing single-color 3D printers, has a wide range of applications, low cost, and is easy to promote.

[0023] Preferably, during step S2, the segmentation thickness is adjusted according to the actual situation to ensure that the color of any position on the slice remains consistent in the thickness direction.

[0024] Preferably, in step S3, if the color of the wire matches the color in the slice, the length of the wire of that color needs to be included with a margin. The margin is divided into two parts and set at both ends of the wire of that color. That is, the joint of adjacent colored wires is provided with a margin. The former is used to increase redundancy, and the latter is used to flush away the residue of the previous color. If the color of all wires cannot match the color in the slice, multiple short colored wires are mixed together. This mixing refers to splicing together wires of different colors with extremely short lengths (less than or equal to 5mm) to achieve color mixing in the print head during printing, thereby adapting to the color in the slice. Compared with color stacking, this method has better color consistency. When calculating the length of these short wires, the consistency of the mixed colors is used as the benchmark, and there is no need to consider the flushing margin.

[0025] More preferably, in step S5, when printing to the junction of two colors (the mixed short wires are regarded as wires of one color), the single-color printhead is flushed or cleaned with a different color.

[0026] More preferably, step S5 further includes a step of color recognition of the monochrome nozzle outlet, which is achieved by an added visual acquisition unit.

[0027] More preferably, the color recognition step includes image grayscale conversion, color space conversion, and feature threshold comparison. If the comparison result exceeds the set range, printing is paused and an alarm is triggered.

[0028] More preferably, step S5 also dynamically adjusts the time of the color-changing rinsing or color-changing cleaning based on the color recognition results to reduce losses.

[0029] More preferably, the visual acquisition unit includes a camera that moves with the monochrome nozzle.

[0030] In one embodiment, the optimized printing path in step S3 is a single path from the starting point to the ending point. During the movement, the single-color printhead in step S5 does not pause, and its corresponding multi-color filament, such as... Figure 1 As shown, there are multiple segments of the same color in the wire used to print single-layer slices.

[0031] In another embodiment, the optimized printing path in step S3 is a series of paths from the starting point to the ending point, each path corresponding to a color, and the corresponding multi-colored thread is as follows: Figure 2 As shown, in the filaments for printing single-layer slices, there is only one segment of the same color. During the movement, if the color at the current position is the same as the corresponding color, printing is performed at the set speed; if the color at the current position is different from the corresponding color, extrusion is paused and the filaments pass through quickly.

[0032] In another embodiment: 1. The wire arrangement process is as follows: before the printing program G-code starts: record the number of the first color wire, extend the wire of that color, and leave a flushing length (default 10 cm, which can be set by the user in the UI).

[0033] 2. Traverse all slices and find the maximum value N of the number of color switching times for each slice, which is used for wiping tower generation.

[0034] 3. Start calculating the wire length corresponding to each color from the lowest layer (layer 0) slice.

[0035] 4. Cut wire segments of the corresponding color (including excess material) according to the wire length, and fuse them together to form a multi-colored wire.

[0036] 5. Generate the G-code required for printing based on the length of each color wire segment in the multi-color wire.

[0037] 6. Adjust the G-code to insert an erasure code when the printout reaches the margin.

[0038] 7. Export G-code using the open-source software Orcaslicer, generating _color_schedule.csv: (Example) Figure 3 As shown.

[0039] Row 0 is the feeding and rinsing row, which indicates the length automatically extruded when the machine first loads multi-colored wire.

[0040] The wiping tower generation process includes: dividing the wiping tower into N rectangular bands based on the maximum value N of the number of color switching times for each slice. The bandwidth of a single band is determined based on the width, cross-sectional area, and slice thickness of the multi-color wire.

[0041] In another embodiment: Point 4 above uses a mixture of short red and short yellow filaments to achieve orange color. This color mixing is performed during monochrome printhead printing, and the corresponding _color_schedule.csv file is as follows: Figure 4 As shown.

[0042] The 3D printing method provided in this application only requires the addition of a lightweight vision acquisition unit. The core structure of the monochrome 3D printer, such as the extrusion, nozzle, and transmission, does not need to be modified. It can be upgraded to multi-color capability and adapt to the requirements of mixed-color printing, with low modification cost and low failure rate. It can achieve fully automated operation without manual intervention in color changing or marking color changing points, and relies on algorithms and visual recognition to achieve closed-loop control. It supports multi-color printing on the same layer: it can print patterns, reliefs, logos, and local color structures, and the forming effect is comparable to high-end hardware multi-color equipment. Through color recognition at the monochrome nozzle exit, it can significantly improve color changing accuracy and adjust the color changing flushing or cleaning time to reduce multi-color filament loss. It is compatible with most FDM single-nozzle models on the market and has good stability.

[0043] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A 3D printing method, characterized in that, Includes the following steps: S1. Obtain the 3D model data of the product; S2. Divide the 3D model data in S1 into slices suitable for monochrome 3D printers according to the thickness direction; S3. Before printing begins, calculate the required wire length for each color based on the color distribution of each slice in S2, and optimize the printing path; S4. Cut wires of different colors according to the wire length in S3, and connect them together to obtain multi-colored wires; S5. Place the multi-color filament into the filament feed mechanism of the monochrome 3D printer, turn on the monochrome nozzle, and move it along the printing path optimized in step S3 to complete the 3D printing.

2. The 3D printing method according to claim 1, characterized in that: In step S3, if the color of the wire is the same as the color in the slice, the length of the wire of that color needs to be calculated with a margin. The margin is divided into two parts and set at both ends of the wire of that color.

3. The 3D printing method according to claim 1, characterized in that: In step S3, if the color of all the wires cannot match the color in the slice, then multiple short wires of different colors are mixed together. When calculating the length of these short wires, the consistency of the colors after mixing is used as the benchmark.

4. The 3D printing method according to claim 2 or 3, characterized in that: In step S5, when printing to the junction of the two colors, the single-color printhead is flushed or cleaned with a different color.

5. The 3D printing method according to claim 4, characterized in that: Step S5 also includes a step of color recognition of the monochrome nozzle outlet, which is achieved by an added visual acquisition unit.

6. The 3D printing method according to claim 5, characterized in that: The color recognition step includes image grayscale conversion, color space conversion, and feature threshold comparison. If the comparison result exceeds the set range, printing is paused and an alarm is triggered.

7. The 3D printing method according to claim 6, characterized in that: Step S5 also dynamically adjusts the time for color-changing rinsing or color-changing cleaning based on the color recognition results to reduce losses.

8. The 3D printing method according to claim 5, characterized in that: The visual acquisition unit includes a camera that moves with the monochrome nozzle.

9. The 3D printing method according to claim 1, characterized in that: The optimized printing path in step S3 is a single path from the starting point to the ending point. During the movement, the monochrome printhead in step S5 does not pause.

10. The 3D printing method according to claim 1, characterized in that: In step S3, the optimized printing path consists of multiple paths from the starting point to the end point. Each path corresponds to a color. During the movement, if the color at the current position is the same as the corresponding color, printing is performed at the set speed. If the color at the current position is different from the corresponding color, extrusion is paused and the process proceeds quickly.

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