Method for building multi-layer material stacking structure in three-dimensional space based on color chartlet to achieve three-dimensional model multi-color printing

Abstract

The invention discloses a method for building a multi-layer material stacking structure in a three-dimensional space based on color mapping to achieve three-dimensional model multi-color printing, and belongs to the technical field of 3D printing. The method aims at solving the problem that the color gamut of an existing FDM printing technology is limited. The core of the method is that after a three-dimensional model with a color map is obtained, a multi-layer stacking scheme composed of multiple preset basic color semitransparent materials is calculated through a color decomposition algorithm according to each target color on the map; according to the scheme, generating a multi-layer developing structure with physical thickness along the normal direction of the surface of the model, and converting the multi-layer developing structure into a printing path file (G-code) containing a multi-material switching instruction; and finally, the 3D printer executes printing according to the path file. Two-dimensional color information is mapped into a material stacking structure in a three-dimensional space, the transmission color mixing effect of materials is utilized, the color gamut is greatly expanded under a limited base material, and the method has the advantages of being low in cost and high in compatibility.

Description

Technical Field

[0001] This invention belongs to the field of 3D printing technology. Specifically, it relates to a fused deposition modeling (FDM) printing method that utilizes multi-layer material stacking to achieve rich color representation, and is particularly suitable for processing three-dimensional models with complex color textures. Background Technology

[0002] Fused deposition modeling (FDM) 3D printing technology has been widely used in both manufacturing and consumer sectors due to its advantages such as customized production capabilities, rapid prototyping, and high material versatility. However, standard FDM technology has inherent limitations in achieving multi-color or full-color printing. Existing multi-color FDM solutions mainly fall into two categories: The first type is surface coloring technology, which involves printing a monochrome or white model first, and then coloring the model surface using inkjet or other methods. The color in this solution only adheres to the surface layer, and the printing equipment needs to provide additional color nozzles and technical support. The second type is color mixing extrusion technology, which generates the target color in real time by mixing multiple basic pigments at the print head. The color performance of this solution is limited by the types of consumable colors that the printer can mix at the same time and the precision of the color mixing mechanism. The achievable color gamut is limited, the color transition is abrupt, and there may be problems such as color bleeding and printhead clogging. To address these issues, the industry has developed several advanced solutions, such as manual coloring after printing or using expensive full-color inkjet / binder jet 3D printing technology. These solutions generally suffer from high costs, complex processes, or the need for additional post-processing, contradicting the core advantages of FDM technology: low cost and rapid prototyping. Therefore, developing a technology that can significantly expand the color gamut on standard multi-color FDM printers at low cost has significant market value and practical implications. Summary of the Invention

[0003] The purpose of this invention is to solve the problem of limited color printing in existing FDM technology and to provide a method for multi-color printing of 3D models based on multi-layer material stacking. This method, through an algorithm-driven, structured color development approach, enables multi-material FDM printers to display a richer range of colors far exceeding the quantity of their basic consumables, on a mature hardware platform.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A method for multi-color printing of 3D models based on multi-layer material stacking is proposed. Its core idea is "algorithm decomposition, structure color rendering." This method transforms the complex color matching problem into a specific material stacking problem, specifically including the following steps: Step 1: Obtain a 3D model with color maps. Color maps provide point-by-point target color definitions for the model's surface; Step 2: Preset the basic printing materials and stacking layers. Select a set (e.g., 8 types) of basic color consumables with good translucency properties, and set a fixed stacking layer number N (e.g., 4 layers). Step 3: Perform color decomposition calculations. For each target color on the color map, the system uses a core color decomposition algorithm to calculate the optimal multi-layer stacking sequence. This sequence specifies the types and order of basic materials to be used in each of the N layers, ensuring that the color presented by the light transmission and mixing after stacking these N layers is closest to the target color. Step 4: Generate multi-layer structure and printing path. Based on the calculated stacking sequence, the software "clad" the model surface with an N-layer structure and physical thickness along the normal direction of the model surface; Step 5: Perform multi-material printing. Following the instructions in the G-code, the multi-material FDM printer precisely stacks different base color materials layer by layer on the model's surface, ultimately forming a physical entity.

[0005] The advantages of this invention are: 1) Significantly expands the color gamut: By stacking M basic consumables in N layers, M^N color combinations can theoretically be achieved, realizing an exponential expansion of the color gamut; 2) Cost and performance advantages: This method is mainly based on software and algorithms, requiring no hardware modification to existing FDM printers, and is compatible with various commercially available semi-transparent printing consumables; 3) Structural color rendering with unique effects: The colors are generated by the material structure with physical depth, and the color rendering has a sense of layering and transparency. Attached Figure Description

[0006] Figure 1 This is an overall flowchart of one embodiment of the method of the present invention; Figure 2 This is a schematic diagram illustrating the principle of the color decomposition algorithm of this invention; Figure 3 This is a demonstration of the final effect of one embodiment of the present invention. Detailed Implementation

[0007] The technical solution of the present invention will now be clearly and completely described in conjunction with the accompanying drawings.

[0008] Reference Figure 1 A complete implementation process of the present invention is as follows: S1: Acquire and process the target model The user inputs a 3D model file with color textures. In this embodiment, a cuboid model (OBJ format) with multiple color gradients on its surface and its corresponding color texture (PNG format) are selected.

[0009] S2: Parameter Setting In the printing software, set the printing parameters. In this embodiment, select a set of translucent PETG filament containing eight basic colors, specifically: cyan (C), magenta (M), yellow (Y), white (W), black (K), red (R), green (G), and blue (B). Set the number of stacked layers of the color development structure to N=4, with each layer having a thickness of 0.2mm.

[0010] S3: Color Decomposition and Scheme Generation Reference Figure 2 The software begins processing the color map. For a dark blue pixel (the target color) on the map, a color decomposition algorithm is initiated. The goal of this algorithm is to find a stacked sequence of four basic materials that best approximates the optical effect of the target dark blue. For example, the algorithm might determine the optimal sequence as: [Layer 1: Blue, Layer 2: Cyan, Layer 3: Black, Layer 4: Transparent / White]; Similarly, for a green pixel on a texture, the algorithm might output another sequence, such as [Layer 1: Yellow, Layer 2: Cyan, Layer 3: Yellow, Layer 4: White]; This calculation process iterates through all areas of the texture, generating a unique 4-layer material stack "recipe" for the entire texture.

[0011] S4: Generate multi-layer structure and print path The path generation module begins constructing the geometry based on the stacking scheme obtained in step S3. For each triangular facet on the model surface, it creates four offset faces outward (or inward) along its normal direction, forming a thin shell with a thickness of 0.8 mm (4 * 0.2 mm). This thin shell is logically divided into four layers, each of which is assigned the corresponding material properties calculated in step S3. The slicing engine then slices this model (main body + colored shell) with complete material information to generate the final printing G-code. This G-code file contains the movement path of the print head in XYZ space, as well as instructions for switching materials when printing different layers and regions of the colored shell.

[0012] S5: Perform layered printing The generated G-code file is sent to an FDM printer that supports eight materials. The printer begins operation according to the G-code instructions. When printing the outer surface of the cuboid model, the printer will use blue material for the first layer in the dark blue area and yellow material for the first layer in the green area, according to the instructions; when printing the second layer, it will switch to cyan material in the dark blue area and cyan material in the green area... and so on, until all four color structures and the main body of the model are printed.

[0013] The final mixed-color cuboid's color is formed by mixing four layers of semi-transparent materials, greatly enriching its color expression.

[0014] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for multi-color printing of a three-dimensional model based on color map to construct a multi-layer material stack structure in a three-dimensional space, the method comprising: The method comprises the following steps: ​ Step one, obtaining a three-dimensional model file and a color map corresponding thereto, the color map providing target color information of each point on the model surface; Step two, presetting a base color material and a number N of stacking layers; Step three, for any target color on the color map, a multi-layer stacking sequence composed of the base color material and containing N levels is determined through color decomposition algorithm, the sequence defining the type and order of the base color material used by each level; Step four, based on the multi-layer stacking sequence, an N-layer material stacking structure along the normal direction is generated for the three-dimensional model surface, and a printing path file containing multi-material printing control instructions is directly generated; Step five, controlling a multi-color 3D printer to perform printing according to the printing path file to form the material stacking structure, so as to realize the target color through the optical superposition effect of multi-layer materials.

2. The method of claim 1, wherein, In step two, the base color material is eight kinds of translucent materials, namely cyan, magenta, yellow, black, white, red, green and blue materials.

3. The method of claim 1, wherein, In step two, the number N of stacking layers is an integer between 3 and 8.

4. The method of claim 1, wherein, In step four, the thickness of each level in the material stacking structure is 0.1-0.4 mm.

5. The method of claim 1, wherein, The colored surface of the model is mainly realized by constructing a multi-layer base color stacking structure in space based on the transmission and mixing effect of multi-layer translucent materials.

6. The method of claim 1, wherein, The printing path file is a G-code file, and the multi-material printing control instruction is a tool switching instruction for switching different base color material printing heads.

7. A system for enabling multi-color printing of a three-dimensional model, the system comprising: The method comprises: An input module for obtaining a three-dimensional model file and a color map corresponding to the three-dimensional model surface; A layer calculation module for analyzing a multi-layer stacking sequence composed of multiple preset base color materials into a multi-layer stacking sequence through a color decomposition algorithm for a target color on the color map; A path generation module for generating a printing path file containing multi-material printing control instructions according to the multi-layer stacking sequence, the file being used to guide a printing mechanism to build a multi-layer material stacking structure; A control module for sending the printing path file to a multi-material three-dimensional printer and controlling it to perform printing.

8. The system of claim 7, wherein, The layer calculation module is configured to use eight base color materials and a number N of stacking layers between 3 and 8 to determine the multi-layer stacking sequence.

9. The system of claim 7, wherein, When generating the printing path file, the path generation module sets the thickness of each layer of material in the multi-layer stacking structure to 0.1-0.4 mm.

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