Gilding colorful 3D printing material prepared based on multiple runners and preparation method of gilding colorful 3D printing material

Abstract

According to the gilding colorful 3D printing material prepared based on the multiple runners and the preparation method of the gilding colorful 3D printing material, through the multi-runner die head design and the double-machine cooperative co-extrusion technology, the structure of a continuous main body phase and multiple continuous dispersed phases evenly distributed in the circumferential direction is constructed, and cooperation of the high-end colorful visual effect and the excellent printing performance is achieved. The method also successfully solves the key problem that the traditional blending material cannot give consideration to AMS compatibility, high-end colorful effect and material performance, and breaks through the bottlenecks of limited material combination, serious thermal degradation and single visual effect in the prior art.

Description

Technical Field

[0001] This invention belongs to the field of 3D printing materials technology, and particularly relates to a gold-plated iridescent 3D printing material based on multi-channel preparation and its preparation method. Background Technology

[0002] As an advanced additive manufacturing method, 3D printing technology has been widely used in various fields such as industrial design, medical and health care, cultural and creative industries, education and research, and consumer electronics, thanks to its high degree of design freedom, personalized customization capabilities, and efficient molding of complex structures. With the continuous upgrading of application demands, users are not only placing higher requirements on the functionality, structural strength, and dimensional accuracy of 3D printed products, but also increasingly emphasizing their aesthetic appeal, especially visually impactful decorative surface effects such as gradient colors, two-color / multi-color splicing, metallic luster, and high-end dazzling visual expressions like gilding. These are gradually becoming key elements for market differentiation.

[0003] Currently, the main technical approach to achieving vibrant colors in 3D printing materials is through single-color blending. While this approach has produced visual effects similar to "vibrant colors" such as two-color, multi-color, or gradient colors, and even attempted to simulate the texture of gilding, blended materials have many performance defects (such as difficulty in achieving smooth filament changing in the AMS automatic material changing system), and there are also many limitations between the blended materials (such as the use of high-melting-point and low-melting-point materials being limited by the ambient temperature of the blending extrusion environment).

[0004] In order to improve the performance of 3D printed products, the current market uses co-extrusion to avoid the shortcomings of materials. This process can solve some of the printing defects of materials, but the printing filament of this structure cannot actively control "when the core layer is exposed" or "local color change" during printing, so it is difficult to achieve dazzling effects such as floating color, gold plating, and color layering. Summary of the Invention

[0005] This invention proposes a multi-channel fabrication method for creating a gilded iridescent 3D printing material. By constructing a structure of "continuous main phase + multiple circumferentially uniformly distributed continuous dispersed phases," it achieves a synergistic effect of high-end iridescent visual effects and excellent printing performance. This method also successfully solves the key challenges of traditional blended materials in achieving AMS compatibility, high-end iridescent effects, and material performance simultaneously, overcoming the bottlenecks of limited material combinations, severe thermal degradation, and limited visual effects in existing technologies.

[0006] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0007] A method for preparing a gilded iridescent 3D printing material based on multi-channel fabrication includes the following steps:

[0008] S1: Use a plastic granulator to prepare material 1 granules and material 2 granules for multi-channel applications;

[0009] S2: Material 1 particles and Material 2 particles are fed into two single-screw extruders respectively. The single-screw extruder corresponding to Material 1 is equipped with a multi-channel die, and the single-screw extruder corresponding to Material 2 is equipped with a single-channel die. The two single-screw extruders work together through melt co-extrusion process.

[0010] S3: During the co-extrusion process, material 1 forms multiple dispersed streams through a multi-channel die head, and material 2 forms the main substrate stream through a single-channel die head. Multiple material 1 streams are introduced into material 2 at the outlet and quickly bond with it, achieving uniform distribution and firm bonding of material 1 in material 2.

[0011] S4: The co-extruded composite filament is cooled and shaped by a cooling device to obtain a structurally stable multi-channel co-extruded 3D printing filament.

[0012] In existing technologies, while extruding different colored or functional materials in a molten state can achieve a certain degree of color mixing or gradient effects, it is essentially a uniform or non-uniform mixture within the material, resulting in a blurred, transitional color distribution on the surface. It cannot create a clear, three-dimensional, metallic-lustered "gilding" or "multi-color" decorative effect. This invention, however, uses a multi-channel die to control material one, forming multiple independent streams and precisely embedding them into the substrate material two. After printing, the finished product surface will have a visual effect resembling metal wires embedded in the main material. During the printing process, the filament can be rotated at a certain angle to create different regular interwoven colors on the product surface, realistically reproducing the "gilding" texture and significantly improving the appearance and artistic expression of 3D printed products. Furthermore, for 3D printing filaments formed by co-extrusion with a shell covering the core layer, it is difficult to actively control when the core layer is exposed during printing, making it difficult to achieve vibrant effects such as floating colors, gilding, and multi-color effects.

[0013] It is worth mentioning that the multi-channel co-extrusion 3D printing filament produced according to the process flow of this invention, in addition to achieving high-end dazzling visual effects such as floating color, gold plating, and color layering, also effectively solves the technical problem of the difficulty in coexistence between materials with different melting points. In the traditional blending extrusion manufacturing process, all component materials need to be melted and mixed in the same screw cavity. Therefore, the extrusion temperature must reach at least the processing temperature of the material with the highest melting point among the components. This condition often leads to thermal decomposition, degradation, gasification, or even carbonization of low-melting-point materials during prolonged high-temperature residence, which not only affects the color stability and surface quality of the final product, but also produces defects such as bubbles and broken filaments, seriously restricting the diversity and functional expansion of material combinations. In the preparation process described in this invention, material one and material two are melted and transported by two independent single-screw extruders, and each completes the plasticization process within its optimal temperature range—the high-melting-point material can be fully melted in the high-temperature zone, while the low-melting-point material avoids overheating exposure, maintaining its chemical structural integrity and physical property stability. Subsequently, through a multi-channel die design, Material 1 is formed into multiple independent and dispersed melt streams. These streams are introduced into the already molten Material 2 matrix just before exiting the die. At this point, Material 1, already in a molten state, can achieve rapid and strong bonding with Material 2. Simultaneously, due to the extremely short contact time, Material 1 avoids prolonged exposure to the high-temperature environment required by Material 2, effectively preventing thermal decomposition of the low-melting-point material due to overheating. In this way, high-melting-point and low-melting-point materials can achieve stable composite bonding while maintaining their respective performance integrity. This not only broadens the range of functional material combinations suitable for vibrant color printing but also provides a material foundation for achieving good interlayer fusion and structural integrity in subsequent FDM printing processes.

[0014] It is also worth mentioning that the multi-channel co-extrusion 3D printing filament prepared by the process of this invention fully utilizes the physical and chemical changes that occur when the material undergoes secondary melting during the printing process. This effectively solves common technical problems in fused deposition modeling (FDM) of special materials, including poor adhesion between the material and the printing substrate, insufficient interlayer bonding, low melt extrusion efficiency, and performance degradation of functional materials. Through multi-channel structure design and material compatibility control, each component fully exerts its characteristics and works synergistically in the molten state, ultimately achieving high-quality, high-reliability printing while ensuring that the performance of functional materials is fully presented.

[0015] Preferably, the multi-channel die head has a feed channel at its inlet end and multiple discharge channels at its outlet end. These discharge channels are arranged in a ring array around the central axis of the die head, and the feed channel and discharge channels are interconnected. By arranging the multiple discharge channels in a ring array around the central axis of the die head, multiple streams of material one can be introduced into the melt flow of material two in a highly symmetrical and uniform manner. This structural design fundamentally prevents defects such as skewed color stripes, dense or sparse local effects that may occur in the final filament and printed products due to uneven stream distribution, ensuring the consistency, predictability, and high quality of the "gilding" visual effect. Furthermore, the ring array flow channel design conforms to fluid mechanics principles, reducing flow resistance and turbulence within the die head, and helping each stream to be extruded with a smooth and balanced flow rate and pressure. This stable flow pattern reduces pulses and fluctuations during filament production, which is crucial for ensuring the constant diameter of the composite filament and the bonding quality of the interface, thereby directly improving the geometric accuracy and reliability of the final 3D printed filament.

[0016] The cross-sectional diameter of Material 1 can be adjusted by controlling the extrusion speed of the single-screw extruder. By controlling the extrusion speed of the single-screw extruder corresponding to Material 1, the cross-sectional diameter of each strand of Material 1 embedded in the substrate can be precisely adjusted. This means that, according to the design requirements of the final product, changes from delicate metallic luster to a rugged gilded inlay effect can be flexibly achieved. It also allows for relatively convenient changes in the proportion of different materials in the filament to manufacture filaments with different functional properties (such as changes in hardness).

[0017] Preferably, the number of discharge channels is 2 to 5, and more preferably 3, with equidistant intervals between two adjacent discharge channels. Controlling the number of discharge channels within the range of 2 to 5 allows for the formation of clearly distinguishable multi-point or striped decorations while avoiding visual crowding, effectively mimicking the artistic characteristics of line outlining in traditional gilding techniques. More preferably, 3 channels form a three-dimensionally symmetrical triangular distribution, providing optimal visual balance and a three-dimensional effect, and offering better structural support due to the combination of soft and hard materials.

[0018] It is worth mentioning that multiple discharge channels are equidistantly arranged around the central axis, ensuring that the multiple strands of material one are evenly distributed in the circumferential direction, giving the internal structure of the composite filament good radial symmetry. This symmetrical layout effectively balances the stress distribution inside the material, preventing filament bending, eccentricity, or extrusion direction deviation caused by strand aggregation, improving the roundness accuracy and filament feeding smoothness of the filament, and is especially suitable for high-precision 3D printing equipment and AMS automatic material changing systems, reducing the occurrence of failures such as head blockage, filament breakage, or filament change jamming.

[0019] Preferably, the single-channel die head and the multi-channel die head are coaxially arranged. This coaxial arrangement ensures that the main melt flow of material two flows uniformly out from the central axis, while multiple streams of material one are symmetrically distributed and embedded around this central axis. This configuration of "central substrate + circumferential symmetry / functional layer" gives the composite filament a completely symmetrical physical structure in any radial direction. This symmetry ensures that the shrinkage stress in all directions is uniformly balanced during the cooling and solidification process of the filament, fundamentally eliminating defects such as wire bending, warping, or eccentricity, thereby ensuring that the final filament has good geometric accuracy and dimensional consistency.

[0020] This invention also provides a gold-plated iridescent 3D printing material based on multi-channel fabrication, wherein the multi-channel co-extrusion 3D printing filament comprises:

[0021] A continuous main phase composed of material two;

[0022] Multiple dispersed phases composed of material one are embedded and uniformly distributed in the continuous main phase composed of material two, and extend continuously along the length direction of the multi-channel co-extrusion 3D printing filament; wherein, the multiple dispersed phases are uniformly arranged circumferentially along the central axis of the multi-channel co-extrusion 3D printing filament, and each dispersed phase forms a strong interfacial bond with material two, without obvious phase separation or interfacial defects.

[0023] The unique structure of "continuous main phase + multiple circumferentially uniformly distributed continuous dispersed phases" prepared by the process method of this invention is the fundamental reason why it can achieve high-end dazzling effects. Multiple dispersed phases extend continuously along the length direction and are evenly distributed circumferentially, ensuring the formation of clear, irregular, or discontinuous gilded textures in the printed product, with a visual effect far superior to the blurry color dot distribution of traditional blended materials. Because the dispersed phases are continuously and uniformly distributed, users can actively create rich, evenly distributed, and highly three-dimensional and flowing gilded effects on the surface of the product simply by rotating the filament in the printer. This effect breaks through the technical bottleneck of traditional 3D printed products having single colors and dull appearances, greatly enhancing the aesthetics and artistic value of the product.

[0024] A prior application (application number: 202411823129.2) discloses a technical solution to address the difficulty of smoothly changing flexible filaments in an automated material changing system (AMS) during fused deposition modeling (FDM). This solution involves covering an inner flexible material with a higher elongation at break with an outer material of moderate hardness, good tensile strength, but low elongation at break. This allows for smooth material changing in the AMS and successful FDM printing of flexible products. However, in the prior art, although the outer rigid material provides initial rigidity, after repeated clamping, bending, and dragging by gears in the AMS system, the continuous soft core layer may still experience axial compression, radial bulging, or local flattening. This leads to uneven wire diameter, increased filament feeding resistance, and in severe cases, filament jamming or material breakage, affecting the reliability of material changing.

[0025] In contrast, this invention can achieve the same or even better functional goals through reasonable material selection: for example, material two (the main phase) is made of rigid TPU with moderate hardness, good tensile strength, and low elongation at break, giving the filament good overall rigidity and dimensional stability; at the same time, material one (the dispersed phase) is made of flexible TPU with low hardness and high elongation at break, ultimately forming a structure of "rigid main phase supporting or partially wrapping flexible dispersed phase". This structure allows the filament to have sufficient rigidity at room temperature to smoothly pass through the transmission gears and guide channels of AMS, achieving stable material changing and multi-color switching. During the high-temperature melting process of the FDM printhead, the internal and external materials are fully mixed, releasing flexibility and functional characteristics, thus taking into account both AMS compatibility and the flexibility requirements of the final product. Importantly, the continuous main phase composed of rigid TPU forms a robust skeleton that can effectively resist external radial compressive stress and prevent local collapse or deformation. Therefore, the filament prepared by this invention ensures that the filament maintains a stable circular cross-section and uniform diameter throughout the entire transmission process, significantly reducing the risk of poor filament feeding or material change failure caused by deformation, and further improving the reliability and compatibility of the filament of this invention in the AMS automatic material change system.

[0026] The continuous main phase is a solid columnar matrix, while the dispersed phase is strip-shaped or filamentous. Compared to other irregular shapes (such as dots or sheets), the "strip-shaped or filamentous" dispersed phase morphology creates clearer, sharper, and more coherent decorative textures in the printed product. This structure maximizes the simulation of the lines inlaid with gold wire in traditional gilding techniques, giving the final product's surface iridescent effects (such as gilding and floating colors) a strong sense of direction and flowing three-dimensionality, resulting in a more high-end and realistic visual effect. The "solid columnar matrix" provides a pure and uniform background color for these effect lines, preventing interference with the iridescent effect due to uneven substrate material.

[0027] For filaments used in AMS systems, the solid columnar matrix structure endows the filaments with excellent structural density and axial tensile strength, ensuring strong resistance to deformation when the filaments are held and dragged by gears in the AMS system, preventing flattening, collapse, or localized deformation caused by hollow cores or internal defects. Furthermore, the strip-like or filamentous dispersed phase forms a stable and robust interface with the solid matrix, allowing stress to be uniformly transferred and borne by the high-strength matrix, thus ensuring that the filaments will not break or peel off during repeated bending and winding.

[0028] Preferably, the number of dispersed phases is three, which are arranged in a ring array around the central axis of the continuous main phase and form a triangular arrangement in the cross-section. The three dispersed phases are equidistant at 120° intervals on the circumference, forming a stable triangular geometric configuration, giving the composite wire a highly symmetrical internal structure in the cross-section. It is worth mentioning that the triangular structure has good inherent mechanical stability. The uniform distribution of the three dispersed phases on the circumference, combined with the continuous solid matrix, allows the externally applied compressive stress to be uniformly transmitted and dispersed in three symmetrical directions. This structure significantly enhances the wire's resistance to radial deformation caused by repeated clamping of gears in the AMS system, preventing ellipticization, flattening, or local collapse, and helps maintain the roundness and diameter uniformity of the wire.

[0029] Preferably, a portion of the edges of the dispersed phase are exposed on the outer surface of the multi-channel co-extruded 3D printing filament. Traditional coaxial co-extrusion or multiphase co-extrusion materials typically aim for complete encapsulation between phases to ensure the mechanical properties and long-term stability of the composite filament. However, this comes at the cost of completely enclosing decorative or functional phases internally, requiring subsequent processing such as grinding, polishing, or chemical etching to expose them, increasing complexity and cost. This invention, by controlling the distribution depth and size of the dispersed phase, allows its edges to be controllably exposed on the surface, achieving a balance between structural integrity and visual openness. During FDM printing, as the filament melts and deposits layer by layer, these pre-exposed dispersed phase edges naturally extend with the melt flow and remain in the surface layer of the molded part, forming continuous, clear, high-contrast textures or metallic luster bands. Compared to traditional "hidden" structures that require post-processing to reveal their appearance, this invention achieves significant visual effects such as "gilding" and "floating color" without additional steps. Furthermore, because the dispersed phase extends from the interior to the surface, it presents a three-dimensional transition similar to "inlay," resulting in a more natural, coherent, and layered visual appearance.

[0030] Preferably, material one and material two are compatible. During multi-channel co-extrusion, if the two phases are poorly compatible, phase separation, interface blurring, or irregular agglomeration can easily occur in the channel confluence area or cooling stage, leading to distorted dispersed phase morphology and uneven distribution. This invention, by selecting a material system with compatible properties, can effectively suppress such phenomena, ensuring that multiple dispersed phases are stably embedded in the main phase in regular strip or filamentous forms, maintaining the required geometrical precision, and providing a fundamental guarantee for achieving uniform and controllable vibrant visual effects.

[0031] In summary, this multi-channel-based gold-plated iridescent 3D printing material and its preparation method achieve a synergy between high-end iridescent visual effects and excellent printing performance by constructing a structure of "continuous main phase + multiple circumferentially uniformly distributed continuous dispersed phases". This method also successfully solves the key challenges of traditional blended materials in achieving AMS compatibility, high-end iridescent effects, and material performance simultaneously, overcoming the bottlenecks of limited material combinations, severe thermal degradation, and monotonous visual effects in existing technologies. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the multi-channel mold head in the present invention, which is a multi-channel fabrication method for gilded iridescent 3D printing materials. Figure 1 ;

[0034] Figure 2 This is a schematic diagram of the multi-channel mold head in the present invention, which is a multi-channel fabrication method for gilded iridescent 3D printing materials. Figure 2 ;

[0035] Figure 3 This is a cross-sectional view of the multi-channel mold head in the gold-plated iridescent 3D printing material and its preparation method based on multi-channel fabrication of the present invention.

[0036] Figure 4 This is a cross-sectional view of the multi-channel co-extrusion 3D printing filament used in the preparation method of a multi-channel gold-plated iridescent 3D printing material and its preparation method according to the present invention.

[0037] In the picture,

[0038] 1-Material 1; 11-Dispersed Phase;

[0039] 2-Material 2; 21-Continuous main phase;

[0040] 3-Multi-channel die head; 31-Infeed channel; 32-Outfeed channel;

[0041] 4- Multi-channel co-extrusion 3D printing filament. Detailed Implementation

[0042] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0043] A method for preparing a gilded iridescent 3D printing material based on multi-channel fabrication includes the following steps:

[0044] S1: Use a plastic granulator to prepare material 1 particles and material 2 particles for multi-channel applications;

[0045] S2: Material 1 particles and Material 2 particles are fed into two single-screw extruders respectively. The single-screw extruder corresponding to Material 1 is equipped with a multi-channel die 3, and the single-screw extruder corresponding to Material 2 is equipped with a single-channel die. The two single-screw extruders work together through melt co-extrusion process.

[0046] S3: During the co-extrusion process, Material 1 forms multiple dispersed streams through the multi-channel die 3, and Material 2 forms the main substrate stream through the single-channel die. Multiple Material 1 streams are introduced into Material 2 at the outlet and quickly bond with it, achieving uniform distribution and firm bonding of Material 1 in Material 2.

[0047] S4: The co-extruded composite filament is cooled and shaped by a cooling device to obtain a structurally stable multi-channel co-extruded 3D printing filament 4.

[0048] In existing technologies, while extruding different colored or functional materials in a molten state can achieve a certain degree of color mixing or gradient effects, it is essentially a uniform or non-uniform mixture within the material, resulting in a blurred, transitional color distribution on the surface. It cannot create a clear, three-dimensional, metallic-lustered "gilding" or "multi-color" decorative effect. This invention, however, uses a multi-channel die 3 to control material 1 to form multiple independent streams, precisely embedding them into the substrate material 2. After printing, the finished product surface will have a visual effect resembling metal wires embedded in the main material. During the printing process, the filament can be rotated at a certain angle to create different regular interwoven colors on the product surface, realistically reproducing the "gilding" texture and significantly improving the appearance and artistic expression of 3D printed products. Furthermore, for 3D printing filaments formed by co-extrusion with a shell covering the core layer, it is difficult to actively control when the core layer is exposed during printing, making it difficult to achieve vibrant effects such as floating colors, gilding, and multi-color effects.

[0049] It is worth mentioning that the multi-channel co-extrusion 3D printing filament 4 produced according to the process flow of this invention, in addition to achieving high-end dazzling visual effects such as floating color, gold plating, and color layering, also effectively solves the technical problem of the difficulty in coexistence between materials with different melting points. In the traditional blending extrusion manufacturing process, all component materials need to be melted and mixed in the same screw cavity. Therefore, the extrusion temperature must reach at least the processing temperature of the material with the highest melting point among the components. This condition often leads to thermal decomposition, degradation, gasification, or even carbonization of low-melting-point materials during prolonged high-temperature residence, which not only affects the color stability and surface quality of the final product, but also produces defects such as bubbles and broken filaments, seriously restricting the diversity and functional expansion of material combinations. In the preparation process of this invention, material 1 and material 2 are melted and transported by two independent single-screw extruders, and each completes the plasticization process within its optimal temperature range—the high-melting-point material can be fully melted in the high-temperature zone, while the low-melting-point material avoids overheating exposure, maintaining its chemical structural integrity and physical property stability. Subsequently, through the design of the multi-channel die head 3, material 1 is formed into multiple independent and dispersed melt streams. These multiple streams of material 1 are introduced into the already molten material 2 matrix just before exiting the die. At this point, because material 1 is already in a molten state, it can achieve rapid and firm bonding with material 2. At the same time, due to the extremely short contact time, material 1 avoids prolonged exposure to the high-temperature environment required by material 2, thus effectively preventing the thermal decomposition problem caused by overheating of the low-melting-point material. In this way, high-melting-point and low-melting-point materials can achieve stable composite while maintaining the integrity of their respective properties. This not only broadens the range of functional material combinations that can be used for color printing, but also provides a material foundation for achieving good interlayer fusion and structural integrity in the subsequent FDM printing process.

[0050] It is also worth mentioning that the multi-channel co-extrusion 3D printing filament prepared by the process of this invention fully utilizes the physical and chemical changes that occur when the material undergoes secondary melting during the printing process. This effectively solves common technical problems in fused deposition modeling (FDM) of special materials, including poor adhesion between the material and the printing substrate, insufficient interlayer bonding, low melt extrusion efficiency, and performance degradation of functional materials. Through multi-channel structure design and material compatibility control, each component fully exerts its characteristics and works synergistically in the molten state, ultimately achieving high-quality, high-reliability printing while ensuring that the performance of functional materials is fully presented.

[0051] Furthermore, refer to Figures 1 to 3 As shown, the multi-channel die 3 has a feed channel 31 at its feed end and multiple discharge channels 32 at its discharge end. These discharge channels 32 are arranged in a ring array around the central axis of the multi-channel die 3, and the feed channel 31 and discharge channels 32 are interconnected. By arranging the multiple discharge channels 32 in a ring array around the central axis of the die, multiple streams of material 1 can be introduced into the melt flow of material 2 in a highly symmetrical and uniform manner. This structural design fundamentally prevents defects such as skewed color stripes, dense or sparse local effects that may occur in the final filament and printed products due to uneven stream distribution, ensuring the consistency, predictability, and high quality of the "gilding" visual effect. Moreover, the ring array flow channel design conforms to fluid mechanics principles, reducing flow resistance and turbulence within the die, and helping each stream to be extruded with a smooth and balanced flow rate and pressure. This stable flow pattern reduces pulses and fluctuations during filament production, which is crucial for ensuring the constant diameter of the composite filament and the bonding quality of the interface, thereby directly improving the geometric accuracy and reliability of the final 3D printed filament.

[0052] The cross-sectional diameter of Material 1 can be adjusted by controlling the extrusion speed of the single-screw extruder. By controlling the extrusion speed of the single-screw extruder corresponding to Material 1, the cross-sectional diameter of each strand of Material 1 embedded in the substrate can be precisely adjusted. This means that, according to the design requirements of the final product, changes can be flexibly achieved from delicate metallic luster textures to rugged gilded inlay effects. It also allows for relatively convenient changes in the proportion of different materials in the filament to manufacture filaments with different functional properties (such as changes in hardness).

[0053] Furthermore, the number of discharge channels 32 is 2 to 5, preferably 3, with equidistant intervals between two adjacent discharge channels 32. Controlling the number of discharge channels 32 within the range of 2 to 5 allows for the formation of clearly identifiable multi-point or striped decorations while avoiding visual crowding, effectively simulating the artistic characteristics of line outlining in traditional gilding techniques. More preferably, 3 channels form a three-dimensionally symmetrical triangular distribution, providing optimal visual balance and three-dimensionality, and offering better structural support in the mixed soft and hard materials structure.

[0054] It is worth mentioning that multiple discharge channels 32 are equidistantly arranged around the central axis, ensuring that the multiple strands of material 1 are evenly distributed in the circumferential direction, giving the internal structure of the composite filament good radial symmetry. This symmetrical layout effectively balances the stress distribution inside the material, preventing filament bending, eccentricity, or extrusion direction deviation caused by strand aggregation, improving the roundness accuracy and feeding smoothness of the filament, and is especially suitable for high-precision 3D printing equipment and AMS automatic material changing systems, reducing the occurrence of failures such as head blockage, filament breakage, or filament change jamming.

[0055] Furthermore, the single-channel die head and the multi-channel die head 3 are coaxially arranged. This coaxial arrangement ensures that the main melt flow of material 2 flows uniformly out from the central axis, while multiple streams of material 1 are symmetrically distributed and embedded around this central axis. This configuration of "central substrate + circumferential symmetry / functional layer" gives the composite filament a completely symmetrical physical structure in any radial direction. This symmetry ensures that the shrinkage stress in all directions is uniformly balanced during the cooling and solidification process of the filament, fundamentally eliminating defects such as wire bending, warping, or eccentricity, thereby guaranteeing that the final filament has good geometric accuracy and dimensional consistency.

[0056] Reference Figure 4 As shown, the present invention also provides a gold-plated iridescent 3D printing material based on multi-channel fabrication, wherein the multi-channel co-extrusion 3D printing filament 4 comprises:

[0057] A continuous main phase 21 composed of material 2;

[0058] Multiple dispersed phases 11 composed of material 1 are embedded and uniformly distributed in the continuous main phase 21 composed of material 2, and extend continuously along the length direction of the multi-channel co-extrusion 3D printing filament 4; wherein, multiple dispersed phases 11 are uniformly arranged circumferentially along the central axis of the multi-channel co-extrusion 3D printing filament 4, and each dispersed phase 11 forms a strong interfacial bond with material 2, without obvious phase separation or interfacial defects.

[0059] The unique structure of "continuous main phase 21 + multiple circumferentially uniformly distributed continuous dispersed phases 11" prepared by the process method of this invention is the fundamental reason why it can achieve high-end dazzling color effects. The multiple dispersed phases 11 extend continuously along the length direction and are evenly distributed circumferentially, ensuring the formation of clear, irregular, or discontinuous gilded textures in the printed product, with a visual effect far superior to the blurry color dot distribution of traditional blended materials. Because the dispersed phases 11 are continuously and uniformly distributed, users can actively create rich, evenly distributed, and highly three-dimensional and flowing gilded effects on the surface of the product simply by rotating the filament during printing. This effect breaks through the technical bottleneck of traditional 3D printed products having single colors and dull appearances, greatly enhancing the aesthetics and artistic value of the product.

[0060] A prior application (application number: 202411823129.2) discloses a technical solution to address the difficulty of smoothly changing flexible filaments in an automated material changing system (AMS) during fused deposition modeling (FDM). This solution involves covering an inner flexible material with a higher elongation at break with an outer material of moderate hardness, good tensile strength, but low elongation at break. This allows for smooth material changing in the AMS and successful FDM printing of flexible products. However, in the prior art, although the outer rigid material provides initial rigidity, after repeated clamping, bending, and dragging by gears in the AMS system, the continuous soft core layer may still experience axial compression, radial bulging, or local flattening. This leads to uneven wire diameter, increased filament feeding resistance, and in severe cases, filament jamming or material breakage, affecting the reliability of material changing.

[0061] In contrast, this invention can achieve the same or even better functional goals through reasonable material selection: for example, material 2 (the main phase) is made of rigid TPU with moderate hardness, good tensile strength, and low elongation at break, giving the filament good overall rigidity and dimensional stability; at the same time, material 1 (the dispersed phase 11) is made of flexible TPU with low hardness and high elongation at break, ultimately forming a structure in which "the rigid main phase supports or partially wraps the flexible dispersed phase 11". This structure allows the filament to have sufficient rigidity at room temperature to smoothly pass through the transmission gears and guide channels of the AMS, achieving stable material changing and multi-color switching. During the high-temperature melting process of the FDM printhead, the internal and external materials are fully mixed, releasing flexibility and functional characteristics, thus taking into account both AMS compatibility and the flexibility requirements of the final product. Importantly, the continuous main phase 21 composed of rigid TPU forms a robust skeleton that can effectively resist external radial compressive stress and prevent local collapse or deformation. Therefore, the filament prepared by this invention ensures that the filament maintains a stable circular cross-section and uniform diameter throughout the entire transmission process, significantly reducing the risk of poor filament feeding or material change failure caused by deformation, and further improving the reliability and compatibility of the filament of this invention in the AMS automatic material change system.

[0062] In this design, the continuous main phase 21 is a solid columnar matrix, while the dispersed phase 11 is strip-shaped or filamentous. The "strip-shaped or filamentous" form of the dispersed phase 11, compared to other irregular forms (such as dots or sheets), creates clearer, sharper, and more coherent decorative textures in the printed product. This structure maximizes the simulation of the lines inlaid with gold wire in traditional gilding techniques, giving the final product's surface iridescent effects (such as gilding and floating colors) a strong sense of direction and flowing three-dimensionality, resulting in a more high-end and realistic visual effect. The "solid columnar matrix" provides a pure and uniform background color for these effect lines, preventing interference with the iridescent effect due to uneven substrate material.

[0063] For the filaments used in the AMS system, the "solid columnar matrix" structure endows the filaments with good structural density and axial tensile strength, ensuring that the filaments have extremely strong resistance to deformation when held and dragged by gears in the AMS system, preventing flattening, collapse, or local deformation caused by hollow cores or internal defects. In addition, the "strip-shaped or filamentous" dispersed phase 11 forms a stable and strong bonding interface with the solid matrix, and the stress it receives can be uniformly transferred and borne by the high-strength matrix, thus ensuring that the filaments will not break or peel off during repeated bending and winding.

[0064] Furthermore, there are three dispersed phases 11, arranged in a ring array around the central axis of the continuous main phase 21, forming a triangular arrangement in the cross-section. The three dispersed phases 11 are equidistant from each other at 120° intervals on the circumference, forming a stable triangular geometric configuration, giving the composite wire a highly symmetrical internal structure in the cross-section. It is worth mentioning that the triangular structure has good inherent mechanical stability. The uniform distribution of the three dispersed phases 11 on the circumference, combined with the continuous solid matrix, allows the externally applied compressive stress to be uniformly transmitted and dispersed in three symmetrical directions. This structure significantly enhances the wire's resistance to radial deformation caused by repeated clamping of gears in the AMS system, preventing ellipticization, flattening, or local collapse, and helps maintain the roundness and diameter uniformity of the wire.

[0065] Furthermore, some edges of the dispersed phase 11 are exposed on the outer surface of the multi-channel co-extruded 3D printing filament 4. Traditional coaxial co-extrusion or multiphase co-extrusion materials typically aim for complete encapsulation between phases to ensure the mechanical properties and long-term stability of the composite filament. However, this comes at the cost of completely enclosing decorative or functional phases internally, requiring subsequent processing such as grinding, polishing, or chemical etching to expose them, increasing complexity and cost. This invention, by controlling the distribution depth and size of the dispersed phase 11, allows its edges to be controllably exposed on the surface, achieving a balance between structural integrity and visual openness. During FDM printing, as the filament melts and is deposited layer by layer, these pre-exposed edges of the dispersed phase 11 naturally extend with the melt flow and remain in the surface layer of the molded part, forming continuous, clear, high-contrast textures or metallic luster bands. Compared to traditional "hidden" structures that require post-processing to reveal their appearance, this invention can achieve significant visual effects such as "gilding" and "floating color" without additional steps. Furthermore, because the dispersed phase 11 extends from the interior to the surface, it presents a three-dimensional transition similar to "inlay," resulting in a more natural, coherent, and layered visual appearance.

[0066] Furthermore, Material 1 and Material 2 are compatible. During multi-channel co-extrusion, if the two phases are poorly compatible, phase separation, interface blurring, or irregular agglomeration can easily occur in the channel confluence area or cooling stage, leading to morphological distortion and uneven distribution of the dispersed phase 11. This invention, by selecting a material system with compatible properties, can effectively suppress such phenomena, ensuring that multiple dispersed phases 11 are stably embedded in the main phase in a regular strip or filamentous form, maintaining the required geometrical precision, and providing a fundamental guarantee for achieving a uniform and controllable vibrant visual effect.

[0067] In summary, this multi-channel-based gold-plated iridescent 3D printing material and its preparation method achieve a synergy between high-end iridescent visual effects and excellent printing performance by constructing a structure of "continuous main phase 21 + multiple circumferentially uniformly distributed continuous dispersed phases 11". This method also successfully solves the key challenges of traditional blended materials in achieving AMS compatibility, high-end iridescent effects, and material performance simultaneously, overcoming the bottlenecks of limited material combinations, severe thermal degradation, and monotonous visual effects in existing technologies.

[0068] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.

Claims

1. A method for preparing a gilded iridescent 3D printing material based on multi-channel fabrication, characterized in that, Includes the following steps: S1: Use a plastic granulator to prepare material 1 granules and material 2 granules for multi-channel applications; S2: Material 1 particles and Material 2 particles are fed into two single-screw extruders respectively. The single-screw extruder corresponding to Material 1 is equipped with a multi-channel die, and the single-screw extruder corresponding to Material 2 is equipped with a single-channel die. The two single-screw extruders work together through melt co-extrusion process. S3: During the co-extrusion process, material 1 forms multiple dispersed streams through a multi-channel die head, and material 2 forms the main substrate stream through a single-channel die head. Multiple material 1 streams are introduced into material 2 at the outlet and quickly bond with it, achieving uniform distribution and firm bonding of material 1 in material 2. S4: The co-extruded composite filament is cooled and shaped by a cooling device to obtain a structurally stable multi-channel co-extruded 3D printing filament.

2. The method for preparing the gilded iridescent 3D printing material based on multi-channel fabrication according to claim 1, characterized in that, The multi-channel die head has a feeding channel at its inlet end and multiple discharge channels at its outlet end. The multiple discharge channels are arranged in a ring array around the central axis of the multi-channel die head, and the feeding channel and the multiple discharge channels are interconnected.

3. The method for preparing the gilded iridescent 3D printing material based on multi-channel fabrication according to claim 2, characterized in that, The cross-sectional diameter of the first material can be adjusted by controlling the extrusion speed of the single-screw extruder.

4. The method for preparing the gilded iridescent 3D printing material based on multi-channel fabrication according to claim 3, characterized in that, The number of discharge channels is 2 to 5, preferably 3, and two adjacent discharge channels are equally spaced apart.

5. The method for preparing the gilded iridescent 3D printing material based on multi-channel fabrication according to claim 4, characterized in that, The single-channel die head and the multi-channel die head are coaxially arranged.

6. The gilded iridescent 3D printing material prepared by the method according to any one of claims 1 to 5, characterized in that, The multi-channel co-extrusion 3D printing filament includes: A continuous main phase composed of material two; Multiple dispersed phases composed of material one are embedded and uniformly distributed in the continuous main phase composed of material two, and extend continuously along the length direction of the multi-channel co-extrusion 3D printing filament; wherein, the multiple dispersed phases are uniformly arranged circumferentially along the central axis of the multi-channel co-extrusion 3D printing filament, and each dispersed phase forms an interfacial bond with material two.

7. The gilded iridescent 3D printing material based on multi-channel fabrication according to claim 6, characterized in that, The continuous main phase is a solid columnar matrix, and the dispersed phase is in the form of strips or filaments.

8. The gilded iridescent 3D printing material based on multi-channel fabrication according to claim 6, characterized in that, The number of dispersed phases is three. The three dispersed phases are arranged in a ring array around the central axis of the continuous main phase and form a triangular arrangement in the cross-section.

9. The gilded iridescent 3D printing material based on multi-channel fabrication according to claim 6, 7, or 8, characterized in that, A portion of the edges of the dispersed phase are exposed on the outer surface of the multi-channel co-extruded 3D printing filament.

10. The gilded iridescent 3D printing material based on multi-channel fabrication according to any one of claims 6 to 9, characterized in that, Material 1 and Material 2 are compatible.

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