Flow channel staggered integral four-color mixing three-dimensional printing nozzle assembly

Abstract

The application relates to a flow channel staggered integral four-mixing three-dimensional printing nozzle, which belongs to the mechanical structure field, and the basic structure comprises a four-mixing heating aluminum block, multiple flow channel cover plates and a nozzle; the four-mixing heating aluminum block is processed with a material wire inlet hole of a butt joint throat pipe, a melting material cavity, a melting material channel and a melting material outlet surface, and the melting material outlet surface is processed with a cross section staggered flow channel with a partition wall to separate the melting materials of different colors; the technical key point is that a two-stage series mixing process is additionally adopted; the first-stage primary mixing process and the second-stage mixing process are as follows: the two outlets of the flow guide vane of the first-stage mixing process are connected with the melting material inlets of the next-stage double-flow-channel staggered melting material, and the melting materials respectively enter the staggered flow channels, so that the two-stage integral four-mixing structure is realized; the application is simple, reliable in operation and convenient to use in the field of two-color mixing and switching type FDM-3D printers.

Description

[Technical Field]

[0001] This invention belongs to the field of mechanical manufacturing. More precisely, it is an extruder specifically designed for FDM-3D printers and is suitable for multi-color or mixed-color applications. [Background Technology]

[0002] This invention pertains to FDM-3D printing technology: specifically, Fused Deposition Modeling (FDM). rapid prototyping The process involves combining various silk materials (such as...) Engineering plastics ABS Polycarbonate PC Rapid prototyping (FDM) is a method of heating and melting materials and then depositing them layer by layer to form a mold. Most FDM rapid prototyping technologies can use a wide variety of molding materials, such as modified paraffin wax, acrylonitrile / butadiene / styrene copolymer (ABS), nylon, rubber, and other thermoplastic materials, as well as multiphase mixtures, such as mixtures of metal powders, ceramic powders, short fibers, and thermoplastic materials. Among these, PLA (polylactic acid) has advantages such as low shrinkage, easier shaping of printed models, and biodegradability.

[0003] The basic structure and operating principle of the FDM-3D printer are described as follows:

[0004] This mainly includes a feeding mechanism, a mechanical platform that carries the extruder in 2D or 3D (horizontal X-axis and Y-axis movement and vertical Z-axis drive), or a platform where the extruder remains stationary in the vertical direction (Z-axis direction), with movement in the Z-axis direction accomplished by the lifting and lowering of an independent worktable. Currently, the 3D mechanical system driving the extruder for addressing in FDM-3D printers is divided into: a robotic arm 3D displacement system, a belt or screw-driven (X, Y-axis) 2D mechanical transmission + (Z-axis) lifting worktable system, and a vertical 3-screw drive (commonly known as: This includes displacement drive systems that use connecting rods to link the extruder platform, etc.; structural housings that maintain the aforementioned motion; and electronic control systems that support the movement of the mechanical system.

[0005] The process is as follows: Under the control of the electronic system, the extruder moves in the XY plane according to the cross-sectional contour information of the product part. The height of the worktable is adjusted. At the start of printing, the worktable plane is located at the nozzle position of the hot melt nozzle. Thermoplastic filament material is fed to the hot melt nozzle by the filament feeding mechanism, heated and melted into a semi-liquid state in the nozzle, and then extruded and selectively coated onto the worktable. After rapid cooling, a thin sheet contour of approximately 0.1-8mm thickness is formed. After one layer of cross-section is formed, the worktable descends a certain height, and the next layer is clad, as if "drawing" the cross-section and contour layer by layer. This cycle continues until a three-dimensional product part is formed. A dedicated nozzle is often used to lay the support material (the support material is generally water-soluble and is washed away with water after printing). During the printing process, the displacement of the print head on the plane and the up-and-down displacement of the printing platform create a three-dimensional space. The print head and printing platform print according to the generated path. After the print head completes the printing task on one plane, the printing platform automatically descends one layer, and the print head continues printing, repeating the cycle until the finished product is completed. Alternatively, instead of using a Z-axis motor to drive the printing platform's lifting and lowering, the printing platform remains stationary along the Z-axis, while the extruder moves up and down using the Z-axis motor. Another option is to use three vertical lead screws to drive three vertically moving sliders, all of which are hinged to the extruder. An algorithm (using the Z-axis coordinates of the three sliders to determine the extruder's 3D spatial position) achieves the same 3D displacement addressing. The printhead temperature is relatively high, varying depending on the material and the model's design temperature. To prevent issues like warping during printing, the printing platform is typically heated and covered with adhesive paper for easy peeling of the printed product.

[0006] The structural details are as follows: The extruder is the core component of FDM rapid prototyping technology. The extruder's components include the feeder (also called the filament feeder, pusher, etc.) and the extrusion nozzle: throat, heating metal body, heating rod, and temperature sensor, etc. Most extruders use a heating rod to heat the metal block. The plastic filament is extruded through the inlet end of the throat, guided by the throat, and melted at the heated part of the metal block before entering the nozzle area. The molten plastic filament is then subjected to the pressure of the subsequent (piston) feed. The extruded material is forced from the nozzle onto the printing table. The throat in the extruder is made of stainless steel to reduce its thermal conductivity. Some stainless steel throats are also lined with Teflon. Due to prolonged heating during printing, the internal temperature of the throat rises, causing the material inside to remain molten. When printing stops and cooling occurs, the material adheres to the inside of the throat. When printing resumes, this adhered material cannot melt immediately, causing throat blockage. The Teflon lining prevents the material from melting and adhering, significantly improving the blockage problem. The author also added heat sinks and a fan to the extruder, primarily to lower the temperature of the upper part of the throat, preventing blockage and also to dissipate heat from the extruder. The heated and molten plastic filament is extruded from the nozzle onto the printing table. To reduce defects such as warping and shrinkage caused by sudden temperature drops, a heated bed printing table can be used. There are four common nozzle diameters for the nozzles located at the bottom of the extruder: 0.2mm, 0.3mm, 0.4mm, and 0.5mm. The 0.4mm nozzle is the most widely used in the market. After selecting the nozzle diameter, the corresponding parameters should also be set in the printing software, such as the printing layer height and printing speed in the slicing software, to improve the printing quality and accuracy.

[0007] Compared to a single extruder head, a dual extruder head uses two extruders arranged side-by-side, resulting in faster printing speeds and higher efficiency. However, due to its larger mass, it generates greater inertia during operation, requiring higher rigidity from the guide rails. This can reduce printing accuracy. In contrast to a single extruder head, a dual extruder head uses two extruders arranged side-by-side with fixed relative positions. Because it has two nozzles, the dual extruder head is mounted on a slider connected to the guide rail. The nozzle at the bottom of the extruder has four nozzle diameters: 0.2mm, 0.3mm, 0.4mm, and 0.5mm. The 0.4mm nozzle is the most widely used in the market. Of course, nozzles of different diameters can be purchased according to actual needs. It is worth noting that after selecting the nozzle diameter, the corresponding parameters must also be set in the printing software, such as the printing layer height and printing speed in the slicing software, to achieve higher printing quality and accuracy. The gear then tightens the feed filament.

[0008] In near-end feeding extruders, the feeder is mounted on the extrusion head (often a single component containing a heated aluminum block, heating rod, throat, nozzle, and radiator). The material is propelled by a feed motor that directly drives gears, using the frictional force of the gears to force the filament into the throat, where it melts in the metal block and is ejected from the nozzle for printing. This mounting method results in the extruder and print head moving together, leading to a large print head mass and significant inertia during printing, which can cause inaccuracies. Near-end feeding also requires high rigidity in the guide rails. In contrast, far-end feeding mounts the feeder at a distance from the extrusion head, connected by a Teflon guide tube. The drive motor for the far-end feeder is typically mounted on the printer frame, with the filament fed through a guide tube, rather than being mounted on the extrusion head. Compared to near-end feeding, far-end feeding requires greater torque to force the material into the print head.

[0009] The circuitry section of the 3D printer plays a crucial role in controlling the coordinated, orderly, and complete operation of the entire printing process. Some parameters in the firmware are modified as needed to meet printing requirements. It requires two 12V power supplies: one 11A to power the heated bed, and the other 5A to power the extruder, various axis motors, and fans. Since the author did not use a heated bed, only one 12V, 5A power supply is needed. Located in the upper right corner of the expansion board, it has limit switches for the X, Y, and Z directions, which control the printer's origin point during each operation. The stepper motor driver board connects to the stepper motors, enabling the main control board to control them and control the XYZ axis motors and the extruder. The stepper motor driver board is characterized by having only simple stepping and direction control interfaces, five different stepping modes: full, half, 1 / 4, 1 / 8 and 1 / 16, and an adjustable potentiometer to adjust the maximum current output for higher stepping rates. It also features overheat shutdown, undervoltage lockout, cross-current protection, ground short-circuit protection, and load short-circuit protection. The driver board connects to the corresponding interface on the expansion board via pins. The software component of the 3D printer consists of two main parts: upper-level software and lower-level software. Each part is further subdivided. The process involves the author first creating a 3D model of the part using software such as Solidworks, UG, or 3ds Max. After creating the 3D model, the file is saved as an STL file. This STL file is then opened in the slicing software Slic3r. Through a series of print settings, slicing is performed to generate code. This code is then opened in the upper-level software Pronterface and connected to the motherboard. The lower-level software on the motherboard uses Marlin firmware, with parameters pre-set beforehand. After successful connection, the LEDs on the motherboard will flash. Once the printer's heating element reaches the set temperature, printing begins. The following section details the printer's software component. The lower-level software Marlin firmware is free software and can be used directly for software development. When the author uses Marlin firmware in the 3D printer, he only needs to download the firmware in the Arduino IDE software, find the Configuration.h file in the Marlin firmware, and modify the relevant code content according to his own needs. The printer developed by the author requires the following modifications.

[0010] Current technical shortcomings: For FDM-3D multi-color selective printers, the current 2-input 1-output color mixing extruders cannot meet the requirements: they are characterized by very slow color changing, poor color mixing effect, easy thermal clogging, and large size. [Summary of the Invention]

[0011] Purpose of this invention:

[0012] This addresses the shortcomings of current multi-color extruder components for fused deposition modeling (FDM-3D) with two or more colors, including poor color mixing uniformity in four color mixing models.

[0013] Features of this invention:

[0014] A staggered feeding pattern with multiple intersecting channels in the mixing chamber is established, providing mathematical boundary conditions for the feeding distribution to maximize the speed and uniformity of color mixing. Multi-stage... Summary of the Invention:

[0016] The flow channel interlacing integral four-color mixing three-dimensional printing nozzle assembly of the present invention is specifically designed for FDM-3D printers. The main components required for the operation of an FDM-3D printer include: a feeding mechanism containing a feed tray for remotely pushing filament (the filament material is directly driven by a feeding motor to the gears, and the frictional thrust of the teeth is used to squeeze the filament into the throat); a mechanical stage that carries the extruder, which is either stationary or performs 1D, 2D, or 3D motion; and the matching worktable, which in turn performs 3D, 2D, 1D, or stationary motion; a structural housing that maintains the above-mentioned motion; an electronic control unit; a display screen, etc. The working principle has been described in detail in the [Background Art] section and is known prior art, so it will not be elaborated further.

[0017] The staggered flow channel integral four-color mixing 3D printing printhead includes: a four-color mixing heating aluminum block, multiple flow channel cover plates, nozzles, etc. The heating aluminum block is machined with filament inlet holes (for connecting to the throat), a melt chamber, a melt channel, and a melt outlet surface. The melt outlet surface is machined with staggered flow channels with isolation walls to isolate the different colors of melt. The flow channel cover plates are machined with melt outlet holes leading to their respective flow channels. The main installation relationship includes: the nozzle with nozzle holes is screwed into the threads at the bottom of the four-color mixing heating aluminum block; the heating rod and temperature sensor are inserted into their corresponding heating rod holes, etc. The color mixing chamber refers to the space between the flow channel cover plate and the guide plate (first-stage mixing, the first half of the second-stage mixing), and the space between the flow channel cover plate and the inner wall of the nozzle, up to the nozzle nozzle inlet (the second half of the second-stage mixing). The heating aluminum block is heated by the heating rods inserted into the heating rod holes. When the colored filaments pushed by the printer feeder enter their respective filament inlets and melt in their respective melting chambers, they flow through their respective melting channels into the melting outlets, then into their respective cross-sectional staggered flow channels, and finally out through the staggered outlets of the flow channel cover (the outlets of each color are staggered). Afterwards, they enter the mixing chamber, which is the space formed by the flow channel cover and the inner wall of the nozzle. The flow channel cover can have a total of 2-50 staggered outlets, spaced apart for each color's melting outlet. This staggered arrangement of the outlets for each color ensures that the two colors are evenly distributed on the outlet surface of the flow channel cover, achieving uniform distribution with slight diffusion. This results in sufficient mixing and distribution of the two colors. Finally, after being ejected from the nozzle, the mixture exhibits good uniformity.

[0018] In summary, the above method constitutes a staggered color mixing structure; its core components include: a single-color staggered flow channel machined on a four-mixing heating aluminum block, or an independent component; staggered refers to the interlaced and spaced dendritic ends of two flow channels; in addition to sealing the staggered flow channels, the flow channel cover plate also has staggered outlets corresponding to the dendritic ends of the staggered flow channels for each color; and the essential function of the guide plate is to allow the two-color molten materials to converge and mix.

[0019] The assembly and workflow are as follows: The staggered integral four-color mixing 3D printing nozzle of this invention is connected to the heat sink through multiple (4) throats; that is, the throats connecting to the heat sink of the 3D printer are also inserted into the filament inlet of the four-color mixing heating aluminum block. The heat sink is the intermediate body connecting the four-color mixing heating aluminum block and the main body of the 3D printer. The flow channel cover plate covers the melt outlet surface of the four-color mixing heating aluminum block. The melt outlet surface is perpendicular to the direction of filament feeding. The staggered flow channels corresponding to the two sets of melt chambers are processed on this vertical plane for mixing each set of melts; and the two sets of melt chambers A and B, each set of staggered flow channels corresponding to two feeds constitutes a set; next, the above two sets are first mixed in a staggered flow channel manner; and a unique series multi-stage color mixing process is adopted;

[0020] The first-stage (primary color mixing) mixing process is as follows: After passing through the flow channel cover plate (each staggered flow channel and the flow channel cover plate form an independent space for each color), the molten material of each color flows out through multiple staggered outlets opened in the flow channel cover plate (under the pressure of the molten material itself), and then is guided and collected by the guide plate with two outlets, and the two sets of molten materials are collected and mixed respectively, forming two sets of double-mixed molten materials with completed color mixing, and finally flowing out through the two outlets of the guide plate; thus completing the first-stage color mixing, preparing for the next stage of full four-color mixing;

[0021] The second-stage (secondary mixing) mixing process is as follows: the molten material flowing out of the two outlets of the first-stage mixing guide plate is connected to the molten material inlet of the next stage dual-channel staggered flow, and enters its respective staggered flow channel. It is again blocked by the flow channel cover plate and flows out through the multiple staggered outlets opened on the flow channel cover plate. Then it is guided and collected by the guide plate with one outlet. Moreover, the mixing mechanism of the two stages is exactly the same; this achieves the two-stage integral four-color mixing purpose (the concept of integral is the process of successively superimposing the color mixing)

[0022] Further: The cross-sectional staggered flow channels are machined on the molten material outlet surface of the heated aluminum block, or on the flow channel cover plate; or the corresponding cross-sectional staggered flow channels are machined on both the molten material outlet surface of the heated aluminum block and the flow channel cover plate.

[0023] Furthermore: the flow channels below the staggered outlets may be of equal or unequal depth; in the case of unequal depth, the height corresponding to the staggered outlets further away from the melt channel opening is higher, that is, the height of the space left below the staggered outlets is larger, so that the staggered outlets at different distances can obtain a consistent flow rate; or the flow channels are kept at equal depth, so that the opening diameters of the staggered outlets are different, with the opening diameter corresponding to the staggered outlets further away from the melt channel opening being larger, in order to balance the decrease in flow rate caused by the decrease in melt pressure.

[0024] The beneficial effects of this invention are:

[0025] It features uniform color mixing, is less prone to heat clogging, is easy to install and disassemble, has a small size, and does not change user habits. [Image Description]

[0026] Figure 1 Schematic diagram of the structure of a dual-color mixing nozzle assembly for 3D printing with staggered flow channels.

[0027] Figure 2 A schematic diagram of the cross-sectional structure of a dual-color mixing nozzle assembly for 3D printing with staggered flow channels.

[0028] Figure 3 Schematic diagram of the assembly relationship between the melt outlet surface and the flow channel cover plate.

[0029] Figure 4 Schematic diagram of the front and back of the dual-mixed heating aluminum block.

[0030] Figure 5 A schematic diagram showing the front and back assembly of the four-color mixing nozzle, including the flow channels, cover plates, and molten material surfaces.

[0031] Figure 6 A schematic diagram of the shape and disassembly structure of a four-color mixing 3D printing nozzle.

[0032] Figure 7 Schematic diagram of the front and back of the integral four-color heating aluminum block.

[0033] Attached image captions:

[0034] 1. Dual-mix heating aluminum block

[0035] 2. Wire insertion hole

[0036] 3 Melting chamber 1

[0037] 4 Melting chamber 2

[0038] 5 Melting Channel

[0039] 6. Melt outlet surface

[0040] 7. Cross-sectional staggered flow channel 1

[0041] 8. Cross-sectional staggered flow channels 2

[0042] 9-channel cover plate

[0043] 10 Mixing Chamber

[0044] 11 Nozzle 1

[0045] 12 Melt material outlet hole 1

[0046] 13 Melt material 2 outlet hole

[0047] 14. Airflow deflector

[0048] 15 nozzles

[0049] 16. Throat

[0050] 17 Heat sink

[0051] 18 Heating rod holes

[0052] 19. Flow channel step 1

[0053] 20 Flow channel steps 2

[0054] 21. Front of the heated aluminum block

[0055] 22 Heating the reverse side of the aluminum block

[0056] Exploded view of dual-mixing nozzle assembly 23

[0057] 30 Four-way mixed heating aluminum block

[0058] 31 Four-way mixed heating aluminum block front

[0059] 32 Four-way mixed heating aluminum block reverse side

[0060] Exploded view of the four-way mixing nozzle assembly.

[0061] 34 Melting Chamber A

[0062] 35 Melting Chamber B

[0063] 36 Melting Chamber C

[0064] 37 Melting Chamber D

[0065] 38 Melting Channel 1

[0066] 39 Melting Channel 2

[0067] 40 Primary melt outlet surface

[0068] 41 Cross-sectional staggered flow channel A

[0069] 42 Cross-sectional staggered flow channel B

[0070] 43 Cross-sectional staggered flow channel C

[0071] 44 Cross-sectional staggered flow channel D

[0072] 45 Flow channel cover plate 2

[0073] 46 Pre-mixing chamber

[0074] 47 Secondary feed holes

[0075] 48 Cross-section staggered flow channel E

[0076] 49 Cross-section staggered flow channel F

[0077] 50 Secondary melt outlet surface

[0078] 51. Flow channel cover plate 3

[0079] 52 Secondary mixing chamber

[0080] 53 Nozzle 2

[0081] 54, 58 air deflectors

[0082] 56. Throat

[0083] 57 Heat sink

[0084] 59. Material guide bend

[0085] 60 feed tube locking nozzle

[0086] 61. Laryngeal orifice

[0087] [Implementation Case]

[0088] The present invention will be further described below with reference to the accompanying drawings and preferred embodiments:

[0089] like Figure 1 , Figure 2 As shown:

[0090] In particular, as shown in the exploded view (23) of the dual-mixing nozzle assembly: the heat sink (17) is the intermediate body connecting the (heating) nozzle to the 3D printer body (directly fixed on the 3D printer). The flow channel interlaced three-dimensional printing dual-mixing nozzle assembly of the present invention is connected to the heat sink (17) through the throat (16); the nozzle assembly includes: dual-mixing heating aluminum block (1), flow channel cover plate (9), nozzle (11), etc.; the assembly relationship is: the throat (16) is inserted into the filament inlet (2) of the dual-mixing heating aluminum block (1), and the flow channel cover plate (9) covers the dual-mixing... On the molten material outlet surface (6) at the bottom of the heated aluminum block (1), a nozzle (11) with a spray hole (12) is screwed into the thread at the bottom of the double-mixed heated aluminum block (1), and the heating rod and temperature sensor are respectively inserted into the corresponding heating rod holes and other holes; and a cross-sectional staggered flow channel with an isolation wall is machined on the molten material outlet surface (6) to isolate the different colored molten materials; a molten material outlet hole leading to each flow channel is machined on the flow channel cover plate (9); in this way, when the flow channel cover plate is placed on the molten material outlet surface of the double-mixed heated aluminum block, an isolation space is formed between the two to isolate the different colored molten materials;

[0091] During operation, the dual-mixed heating aluminum block (1) is heated by the heating rod. The colored filaments pushed by the printer feeder enter the melting chamber 1 (3) and melting chamber 2 (4) respectively through the filament inlet (2). After being melted, they flow into the melting outlet surface (6) through their respective melting channels (5) and then into the cross-sectional cross-flow channel 1 (7) and cross-sectional cross-flow channel 2 (8). Figure 4 After being marked in the middle, it flows out from the staggered outlets of the flow channel cover (9) (the outlets of each color are staggered); then it enters the mixing chamber (10), which is a space formed by the flow channel cover (9) and the inner wall of the nozzle; after being sprayed out from the nozzle nozzle (15), it has good mixing uniformity.

[0092] like Figure 3 , Figure 4 As shown:

[0093] The front (21) of the dual-mixing heating aluminum block is connected to the throat pipe, and the bottom of the wire inlet (2) is machined with a feed hole: namely, the melt channel (5); on the back (22) of the dual-mixing heating aluminum block, the positions of the cross-sectional intersecting flow channel 1 (7) and the cross-sectional intersecting flow channel 2 (8) can be seen, and an isolation wall (isolation protrusion between the two flow channels) is built between the two flow channels, so that the two molten materials cannot be mixed; as the flow channel moves further away from the melt channel (5) in each flow channel, the pressure of the melt will decrease; in order to ensure that the flow rate of each intersecting outlet is the same, steps of different heights are set below each intersecting outlet in the flow channel, the rule is: the further away from the melt channel, the higher the step. The higher the height corresponding to the staggered outlet of channel (5), the greater the height of the space left below the staggered outlet; that is, the height of channel step 1 (19) is higher than the height of channel step 2 (20); because the pressure of the molten material at channel step 1 (19) is greater than the pressure of the molten material at channel step 2 (20); the material gap (corresponding to the cross-sectional area) at the high-pressure channel step 1 (19) is smaller than the material gap at channel step 2 (20) in order to obtain a consistent flow rate; a material hole is opened in the center of the guide plate (14) to assist in uniform mixing (because a concentration and diffusion process has been carried out).

[0094] The flow channel cover plate (9) has a total of 14 outlets for each color. Each color of material is assigned 7 melt 1 outlets (12) and 7 melt 2 outlets (13). The outlets of each color of material are arranged alternately. In this way, the two colors of material are evenly distributed initially, laying the foundation for the uniformity of mixing.

[0095] like Figure 5 , Figure 6 , Figure 7 As shown:

[0096] Figure 5This is a front and back assembly diagram showing the relationship between the flow channels, cover plates, and molten material surfaces of the four-color mixing nozzle; the left diagram is viewed along the direction of material feed, and the right diagram is viewed along the direction of nozzle discharge.

[0097] Figure 6 A schematic diagram of the shape and disassembly structure of a four-color 3D printing nozzle; the overall view of the nozzle with a heat sink in the upper left corner, and the exploded disassembly view inside the dotted lines on the right and lower right sides.

[0098] Figure 7 A schematic diagram of the front and back of the integral four-color heating aluminum block; from the front, four round holes for inserting the throat tube and four material passage holes can be clearly seen; and on the back, there are double sets of double interlaced flow channels, and the tree-like extension structure of the interlaced flow channels is obvious.

[0099] The structure of the flow channel interlacing integral four-color mixing 3D printing nozzle can be clearly seen from the exploded view (33) of the four-color mixing nozzle assembly, including: four-color mixing heating aluminum block (30), flow channel cover plate 2 (45), flow guide plate (54), nozzle 2 (53); the four-color mixing heating aluminum block (30) is machined with a filament inlet hole as shown on the front side (31) of the four-color mixing heating aluminum block, and a molten material chamber A (34), a molten material chamber B (35) that extend to the bottom of the filament inlet hole. Cavity C (36) and molten material cavity D (37); molten material channel 1 (38) is used to collect the molten materials of two colors from molten material cavity A (34) and molten material cavity B (35), while molten material channel 2 (39) is used to collect the molten materials of two colors from molten material cavity C (36) and molten material cavity D (37); it can also be clearly seen from the reverse side (32) diagram of the four-mixed heating aluminum block; the four material passages of the primary molten material outlet surface (40) are connected to their respective flow channels: horizontal The cross-section staggered flow channel A (41), cross-section staggered flow channel B (42), cross-section staggered flow channel C (43), and cross-section staggered flow channel D (44) are provided; two sets of staggered outlets are machined on the flow channel cover plate 2 (45), each set of outlets being staggered to correspond to the mixing of the melt chamber A (34) and melt chamber B (35), and melt chamber C (36) and melt chamber D (37); and the guide plate (54) also serves to isolate the two sets of mixed materials from each other. At the same time, they are collected in their respective pre-mixing chambers (46); then they are introduced into the cross-sectional cross-flow channels E (48) and F (49) by the secondary feed hole (47), and then discharged from a set of cross-flow channels 3 (51) at the secondary melt outlet surface (50). After being guided by the guide plate (58) into the secondary mixing chamber (52) for final mixing and uniform mixing, they are sprayed out by the nozzle 2 (53).

[0100] The throat hole (61) of the heat sink (57) is connected to the four mixing (heating) nozzles by inserting four throats (56); the heat sink (57) also serves as an intermediate body to connect with the main body of the 3D printer, and its function is the same as... Figure 1 , 2 3 and 4 are the same; like a regular printer, the guide tube (59) is connected to the feed tube lock (60) and the feed channel of the heat sink (57).

[0101] Overall: From Figure 6 , Figure 7 The schematic diagram showing the assembly relationship between the molten material outlet surfaces and the flow channel cover plates at each level shows that the color mixing process of the flow channel interleaved integral four-color mixing 3D printing nozzle is as follows: the feed of the four colors is divided into two groups (two in each group), namely, molten material chamber A (34) and molten material chamber B (35) are one group; and molten material chamber C (36) and molten material chamber D (37) are the other group; next, the above two groups are first mixed in an interleaved flow channel manner; for the first-level molten material outlet surface (40) perpendicular to the nozzle extrusion direction, the interleaved flow channels corresponding to the two groups of molten material chambers are also processed on such a vertical plane (which is easy to process using 3-axis CNC); the two groups of interleaved flow channels used for color mixing are: cross-sectional interleaved flow channel A (41) and cross-sectional interleaved flow channel B (42), and cross-sectional interleaved flow channel C (43) and The cross-section of the staggered flow channel D (44) is completed. After passing through the flow channel cover plate 2 (45), the flow passes through the guide plate (54) for color mixing, thus completing the first stage of color mixing. Then, the two sets of mixed molten materials flowing out of the guide plate (54) pass through the next stage of staggered flow channel for color mixing. The color mixing mechanism of the two stages is exactly the same. This achieves the two-stage integral four-color mixing objective (the concept of integral is the process of sequentially superimposing color mixing). In summary, the above method constitutes the staggered flow channel color mixing structure. The staggered means that the dendritic ends of the two flow channels are staggered and arranged alternately. In addition to sealing the staggered flow channel, the flow channel cover plate also has staggered outlets corresponding to the dendritic ends of the staggered flow channel. The essential function of the guide plate is to make the two-color molten materials gather and mix.

Claims

1. The basic structure of the staggered flow channel integral four-color mixing 3D printing nozzle includes: Four-component heating aluminum block, multiple flow channel cover plates, and nozzles; The aluminum block for four-mixed heating is machined with wire inlet holes for connecting throats, melting chambers, melting channels, and melting outlet surfaces. Furthermore, the melting outlet surface is machined with cross-sectional staggered flow channels with isolation walls to isolate different colored melts. The flow channel cover plate is machined with molten material outlet holes leading to their respective flow channels; the main installation relationship includes: the nozzle with spray holes is screwed into the thread on the bottom of the four-color heating aluminum block, and the heating rod and temperature sensor are respectively inserted into the corresponding heating rod holes and other holes; the color mixing chamber refers to the space between the flow channel cover plate and the guide plate, and between the flow channel cover plate and the inner wall of the nozzle, up to the nozzle spray hole inlet; the heating aluminum block is heated by the heating rod inserted into the heating rod hole, and when the color filaments pushed by the printer pusher pass through the filament inlet holes and enter their respective filament inlet holes, they enter the respective color mixing chambers. After the material in each nozzle is melted, it flows through its respective melt channel into the melt outlet surface, then into its respective cross-sectional staggered flow channel, and finally out through the staggered outlets of each color on the flow channel cover. It then enters the mixing chamber, a space formed by the flow channel cover and the inner wall of the nozzle. The flow channel cover can have a total of 2-50 staggered outlets, spaced apart for each color's melt outlet. This staggered arrangement of the outlets for each color ensures that the two colors are evenly distributed on the outlet surface of the flow channel cover, allowing for even distribution with slight diffusion. The basic workflow of this invention is as follows: the 3D printing nozzle is connected to the heat sink via four throats; the throats connecting to the 3D printer's heat sink are also inserted into the filament inlet of the four-mixing heating aluminum block. The heat sink is the intermediate body connecting the four-mixing heating aluminum block and the 3D printer body. The flow channel cover is placed on the melt outlet surface of the four-mixing heating aluminum block, which is perpendicular to the direction of filament feeding. The staggered flow channels corresponding to the two sets of melt chambers are machined on this vertical plane for mixing the various sets of melts; and the two melt chambers... The system consists of two groups of interlaced flow channels corresponding to each other. The core components of the interlaced color mixing structure for the two groups are: single-color interlaced flow channels machined on the four-mixing heating aluminum block or independent components; interlacing refers to the interlaced and spaced dendritic ends of the two flow channels; in addition to sealing the interlaced flow channels, the flow channel cover plate also has interlaced outlets corresponding to the dendritic ends of the interlaced flow channels; and the essential function of the guide plate is to allow the two-color molten materials to converge and mix. Its distinctive feature lies in the fact that it not only employs a staggered flow channel mixing structure but also incorporates a two-stage series mixing process. The first-stage primary mixing process involves the flow channel cover plate acting as a barrier, creating independent spaces for each color between the staggered flow channels and the cover plate. Under the pressure of the molten material itself, each color flows out through multiple staggered outlets in the cover plate, and then is guided and collected by guide vanes with two outlets, thus mixing the two sets of molten material and forming two sets of double-color mixing. The mixed molten material flows out through the two outlets of the guide vane, completing the first stage of color mixing and preparing for the next stage of full four-color mixing. The second stage of color mixing involves connecting the molten material flowing out of the two outlets of the guide vane in the first stage to the inlet of the next stage's dual-channel staggered molten material, which then enters its respective staggered channel. It is again blocked by the channel cover plate and flows out through the multiple staggered outlets on the channel cover plate. After being guided and collected by the guide vane with one outlet, the two-stage integral four-color mixing structure is achieved.

2. The flow channel staggered integral four-color mixing 3D printing nozzle as claimed in claim 1, characterized in that: The cross-sectional staggered flow channels can be machined not only on the molten material outlet surface of the heated aluminum block, but also on the flow channel outlet cover plate, or corresponding cross-sectional staggered flow channels can be machined on both the molten material outlet surface of the heated aluminum block and the flow channel outlet cover plate.

3. The flow channel staggered integral four-color mixing 3D printing nozzle as claimed in claim 1, characterized in that: The flow channels below the staggered outlets may have equal or unequal depths. In the case of unequal depths, the height corresponding to the staggered outlets further away from the melt channel opening is higher, meaning the height of the space left below the staggered outlets is larger. Alternatively, the flow channels may have equal depths, resulting in different opening diameters for each staggered outlet, with the opening diameter corresponding to the staggered outlets further away from the melt channel opening being larger.

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