Two-component material printing system and method based on FDM printing technology

Abstract

The invention discloses a two-component material printing system and method based on an FDM printing technology, the two-component material printing system based on the FDM printing technology comprises a hollow tubular feeding wire, an extrusion stripping device, a static mixing nozzle, a curing control module and a control system; the hollow tubular feeding wire rod is of a double-component pre-packaging structure. In the two-component material printing system, the hollow tubular feeding wire rod adopts the standard outer diameter of phi 1.75 mm or phi 2.85 mm and can be directly matched with a feeding channel of an existing FDM printer, refitting and upgrading can be achieved without large-scale transformation of original equipment, the wire rod adopts a two-channel coaxial structure or a parallel double-microtube outer wrapping structure, and therefore the wire rod is not prone to being damaged. The outer protection pipe is made of PTFE, PA12 or PE materials which are low in friction and easy to strip, the sealing performance in the storage and transportation process is guaranteed, the outer protection pipe can be efficiently matched with an extrusion and stripping device, the basic structure of existing FDM equipment is fully utilized, and the use cost and the technology switching difficulty of a user are reduced.

Description

Technical Field

[0001] This invention relates to the field of additive manufacturing technology, specifically to a two-component material printing system and method based on FDM printing technology. Background Technology

[0002] Among the mainstream 3D printing technologies, Fused Deposition Modeling (FDM) is one of the most widely used. Its core technology is to tangle thermoplastic material filaments (such as PLA, ABS, TPU, etc.) and melt-deposit them to achieve molding. It occupies an important market share due to its advantages of strong equipment versatility and convenient operation. Liquid silicone (LSR) printing, as a specialized technology for liquid silicone materials, usually uses a dual-pump quantitative mixing system to complete the material supply and mixing. Two-component material printing focuses on A / B two-component reaction curing materials (such as two-component silicone, epoxy resin, polyurethane, etc.), and requires special equipment to ensure the mixing and curing process of the materials.

[0003] Existing 3D printing technologies all have significant shortcomings: FDM technology is limited to thermoplastic solid materials and cannot directly process liquid or reaction-curing materials, greatly limiting its material adaptability; the dual-pump quantitative mixing system used in liquid silicone printing has a complex structure with many precision parts, making subsequent maintenance difficult and costly; two-component material printing has extremely high requirements for the mixing ratio, mixing uniformity, and reaction time of the two components (A and B), and existing equipment that meets these requirements is mostly a large-scale industrial system, which has problems such as large size, high cost, and complex operation, and cannot be adapted to desktop applications; although FDM models have good versatility, existing technologies have not solved the compatibility problem with two-component liquid material printing, and it is not possible to directly use FDM equipment to print two-component liquid materials.

[0004] Therefore, there is an urgent need for a printing system that can convert liquid two-component materials into FDM-feedable materials. This system must be compatible with the structural design of existing FDM equipment, allowing for adaptation without large-scale modifications, and also enable precise mixing and reaction curing of two-component liquid materials for printing. This would break through the material application limitations of existing FDM technology, greatly expand the material system for desktop 3D printing, and meet the printing needs of various two-component reaction curing materials in desktop scenarios. Summary of the Invention

[0005] The purpose of this invention is to provide a two-component material printing system and method based on FDM printing technology to solve the problems existing in the prior art mentioned in the background section.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a two-component material printing system based on FDM printing technology, comprising a hollow tubular feed filament, an extrusion stripping device, a static mixing nozzle, a curing control module, and a control system;

[0007] The hollow tubular feeding line has a two-component pre-packaged structure, and the hollow tubular feeding line stores two liquid materials, A and B.

[0008] The extrusion stripping device is adapted to pull the hollow tubular feeding wire and strip the outer protective tube of the hollow tubular feeding wire along the wire axis, releasing the A and B component liquid materials inside the hollow tubular feeding wire.

[0009] The static mixing nozzle has a built-in static mixing structure, which is suitable for receiving the A and B components of liquid material released by the extrusion stripping device and mixing them evenly.

[0010] The curing control module is adapted to perform in-situ curing of the mixed material output from the static mixing nozzle;

[0011] The control system is adapted to coordinate the operation of the extrusion stripping device, the static mixing nozzle, and the curing control module to stabilize the mixing ratio, feed flow rate, and curing parameters of the A and B component liquid materials during the printing process.

[0012] Preferably, the hollow tubular feeding line has a dual-channel coaxial structure or a parallel dual-microtube outer coating structure. The outer diameter of the hollow tubular feeding line is φ1.75mm or φ2.85mm. The outer protective tube material of the hollow tubular feeding line is PTFE, PA12 or PE. The inner isolation film of the coaxial structure of the hollow tubular feeding line is polytetrafluoroethylene or a biodegradable film. Furthermore, the A and B components inside the hollow tubular feeding line are stored independently and in a sealed manner.

[0013] Preferably, the extrusion stripping device includes a traction unit, a blade module, and a waste pipe recycling channel, wherein:

[0014] The traction unit includes a pair of surface-treated gears or rollers, and the material of the traction unit is aluminum alloy or stainless steel.

[0015] The blade module has a blade material of cemented carbide or ceramic, a cutting edge angle of 25°-35°, and an adjustable peeling length of 10–60 mm.

[0016] The waste pipe recycling channel includes a guide trough and a collection roll or waste box.

[0017] Preferably, the static mixing structure of the static mixing nozzle is a multi-section spiral blade structure, a Kenics type structure, or a baffle composite structure. The number of mixing unit sections in the static mixing structure is 4-20. The nozzle orifice diameter of the static mixing nozzle is 0.2-1.0 mm. The inner wall of the static mixing nozzle is provided with a DLC or PTFE anti-stick coating. The static mixing nozzle is provided with a quick-shut-off valve to prevent dripping.

[0018] A method for FDM printing of two-component materials based on any of the systems described above includes the following steps:

[0019] S1) Connect the hollow tubular feed line containing pre-packaged liquid materials A and B to the feed channel of the FDM printer, and drive the hollow tubular feed line to feed through the traction unit of the extrusion stripping device;

[0020] S2) Using the blade module of the extrusion stripping device, the outer protective tube of the hollow tubular feeding line is cut and stripped along the axial direction of the hollow tubular feeding line, releasing the A and B components of liquid material inside the hollow tubular feeding line. The stripped waste tube is collected through the waste tube recycling channel of the extrusion stripping device.

[0021] S3) The two liquid components A and B enter the static mixing nozzle simultaneously. They are alternately sheared, layered and re-merged by the static mixing structure built into the nozzle to achieve uniform mixing.

[0022] S4) Activate the curing control module according to the material type to allow the mixed material to cure in situ during the deposition process;

[0023] S5) By using the PID closed-loop algorithm of the control system, the traction speed of the extrusion peeling device, the mixing ratio of components A and B, and the curing parameters of the curing control module are adjusted in real time to complete the printing process.

[0024] Preferably, in step S1, the traction speed of the hollow tubular feeding wire and the flow rate of the liquid inside the hollow tubular feeding wire satisfy a certain relationship. Where Q is the instantaneous flow rate and V is the traction speed of the hollow tubular feeding wire. The total cross-sectional area of ​​the inner channels of the hollow tubular feeding line is used to maintain the flow ratio of components A and B in accordance with the target ratio by adjusting the traction speed of the hollow tubular feeding line.

[0025] Preferably, in step S3, the nozzle section of the static mixing nozzle is sequentially divided into a mixing section, a convergence section, and an outlet section, wherein:

[0026] The mixing section is the section where the static mixing structure is located. The converging section is a conical transition structure with an outlet cone angle of 15°–30°. The outlet diameter of the outlet section can be selected as 0.25mm, 0.4mm, 0.6mm, 0.8mm or 1.0mm. A micro electric heating coil is added to the nozzle orifice of the static mixing nozzle. The micro electric heating coil adopts PID temperature control.

[0027] Preferably, in step S4, the curing control module includes a thermal curing unit, a UV-LED light curing unit, and a catalytic self-curing unit, with the curing method matched according to the material characteristics:

[0028] When the material is thermosetting, the temperature is controlled at 40-150°C by the micro heating coil at the nozzle of the static mixing nozzle through the thermosetting unit and the PID temperature control method to achieve curing.

[0029] When the material is photosensitive, curing is achieved by irradiation with 365-405nm UV-LED through the UV-LED curing unit;

[0030] When the material is chemically self-curing, the mixing ratio of components A and B and the feeding rate of the extrusion stripping device are adjusted to match the material's own reaction time to complete the curing process.

[0031] Preferably, after printing, the static mixing nozzle and its built-in mixing structure are rinsed and cleaned.

[0032] When the printing material is washable, warm water is injected through the solution mixing channel of the system for rinsing.

[0033] When the printing material is non-washable, a suitable solvent (such as isopropanol or a solvent specified by the manufacturer) is injected through the solution mixing channel of the system to rinse it, so as to avoid residual material solidifying and clogging.

[0034] At the same time, the flow sensor and pressure sensor configured in the control system are calibrated regularly, and the worn stripping blades in the extrusion stripping device and the nozzle components of the static mixing nozzle are inspected and replaced.

[0035] Compared with the prior art, the beneficial effects of the present invention are:

[0036] 1) In the two-component material printing system of this application, the hollow tubular feed line adopts a standardized outer diameter of φ1.75mm or φ2.85mm, which is consistent with the specifications of commercially available FDM lines. It can be directly adapted to the feed channel of existing FDM printers, and can be upgraded without large-scale modification of the original equipment. The line adopts a dual-channel coaxial structure or a parallel dual microtube outer covering structure. The outer protective tube is made of low-friction, easy-to-peel PTFE, PA12 or PE material, which not only ensures the sealing during storage and transportation, but also can cooperate efficiently with the extrusion peeling device. It makes full use of the basic structure of existing FDM equipment, reducing the user's operating costs and technical switching difficulties.

[0037] 2) The static mixing nozzle of this application has a built-in multi-section spiral blade structure, Kenics type structure or baffle composite structure, which can be flexibly selected according to the material viscosity. Combined with the convergence section design of the outlet cone angle, the A and B components of the liquid alternately shear, stratify and re-merge during the flow process, ensuring that the mixing uniformity is not less than 95%. The control system adopts a PID closed-loop control algorithm and is equipped with a high sampling frequency flow sensor and pressure sensor to monitor and adjust the traction speed and material flow rate in real time, so that the flow ratio of A and B components is stabilized within the target range, effectively avoiding molding defects caused by mixing ratio deviation or uneven mixing, and ensuring the consistency of mechanical properties and dimensional accuracy of the printed products.

[0038] 3) The curing control module of this application integrates a thermosetting unit, a UV-LED curing unit, and a catalytic self-curing unit. It can flexibly match the curing scheme according to the material type. For thermosetting materials, the temperature is precisely controlled at 40-150°C by using a PID temperature control method through the thermosetting unit in conjunction with the micro heating coil at the nozzle, ensuring the curing rate and molding effect. For photosensitive materials, the UV-LED curing unit with a wavelength of 365-405nm is used to achieve real-time surface curing. For chemical self-curing materials, the mixing ratio and feeding rate are adjusted to match the material's own reaction time, and curing can be completed without additional external energy. The diverse curing schemes enable the system to adapt to a variety of reaction curing materials such as two-component liquid silicone, epoxy resin, and polyurethane, greatly expanding the range of printing materials to be selected. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the printing system structure of this application;

[0040] Figure 2 This is a front sectional view of the printing system of this application;

[0041] Figure 3 This is a partial structural diagram of the printing system of this application;

[0042] Figure 4 This is a flowchart of the printing method for this application.

[0043] In the picture:

[0044] 1. Hollow tubular feeding wire;

[0045] 2. Extrusion stripping device; 21. Traction unit; 22. Blade module; 23. Waste pipe recycling channel;

[0046] 3. Static mixing nozzle; 31. Mixing section; 32. Converging section; 33. Outlet section. Detailed Implementation

[0047] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] In the description of the invention, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0049] In the description of the invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0050] In the description of the invention, it should be noted that the execution order of the steps is not limited by the sequence number. The possible changes in the order of some steps, the synchronous execution of steps, and the split execution of steps are all within the scope of protection of this application.

[0051] Please see Figure 1-4 The present invention provides a technical solution: a two-component material printing system based on FDM printing technology, comprising a hollow tubular feeding filament, an extrusion stripping device, a static mixing nozzle, a curing control module and a control system;

[0052] The hollow tubular feeding line has a two-component pre-packaged structure, and the hollow tubular feeding line stores two liquid materials, A and B.

[0053] The extrusion stripping device is suitable for pulling hollow tubular feed wires and stripping the outer protective tube of the hollow tubular feed wires along the wire axis, releasing the A and B component liquid materials inside the hollow tubular feed wires.

[0054] The static mixing nozzle has a built-in static mixing structure, which is suitable for receiving and uniformly mixing the two-component liquid material A and B released by the extrusion stripping device.

[0055] The curing control module is suitable for in-situ curing of the mixed material output from the static mixing nozzle;

[0056] The control system is suitable for coordinating the operation of the extrusion stripping device, static mixing nozzle and curing control module to stabilize the mixing ratio, feed flow rate and curing parameters of the A and B component liquid materials during the printing process.

[0057] Specifically, the two-component material printing system of this application fundamentally solves the shortcomings of traditional FDM technology in handling liquid or reaction-curing materials by integrating a hollow tubular feed filament, an extrusion stripping device, a static mixing nozzle, a curing control module, and a control system. The pre-encapsulated two-component design of the hollow tubular feed filament enables the linear storage and supply of liquid materials, laying the foundation for compatibility with existing FDM equipment. The traction and stripping coordination design of the extrusion stripping device ensures efficient stripping of the outer protective tube and stable release of the internal liquid material, replacing the pump-type feeding of traditional two-component printing and simplifying the structure. The built-in mixing structure of the static mixing nozzle achieves uniform mixing of components A and B, and, combined with the in-situ curing function of the curing control module, meets the molding requirements of reaction-curing materials. The coordinated control of each module by the control system ensures the stability of the mixing ratio, feed flow rate, and curing parameters. The overall system logic is closed-loop, fully utilizing the versatility of FDM equipment while overcoming its material application limitations, providing a feasible system architecture support for desktop printing of two-component liquid materials.

[0058] Specifically, the curing control module and control system are not shown in the figure. The controller of the control system uses ARM / STM32 or embedded Linux (such as Raspberry Pi / NXP), with a real-time sampling rate ≥ 100 Hz. The control strategy of the control system adopts multivariable closed-loop control (flow proportional stage, pressure / flow stage, temperature stage), feedforward compensation, and adaptive PID (or model predictive control MPC optional). The control system is equipped with touch screen operation and PC / cloud connectivity, and supports recipe management (material library: A / B viscosity, reaction time, optimal number of mixing stages, nozzle temperature, UV time, etc.). The control system is existing technology and will not be described in detail here.

[0059] The hollow tubular feeding line features a dual-channel coaxial structure or a parallel dual-microtube outer coating structure. The outer diameter of the hollow tubular feeding line is φ1.75mm or φ2.85mm. The outer protective tube material is PTFE, PA12, or PE. The inner insulating film of the coaxial structure is made of polytetrafluoroethylene or a biodegradable film. Components A and B within the hollow tubular feeding line are stored independently and in a sealed manner. Specifically, the dual-channel coaxial structure or parallel dual-microtube outer coating structure achieves physical isolation between the A and B liquid components, preventing premature reactions during storage and transportation, while ensuring synchronous feeding. The standardized outer diameter of φ1.75mm or φ2.85mm perfectly matches the specifications of commercially available FDM filaments, allowing the filament to be directly connected to the feed channel of existing FDM printers without requiring modifications to the original equipment's feed structure, greatly reducing equipment modification costs and barriers to entry. The outer protective tube is made of PTFE, PA12, or PE materials, which have the characteristics of low friction, easy peeling, and high toughness. This ensures smooth feeding of the filament during the traction process and can work efficiently with the blade module of the extrusion peeling device to achieve complete peeling of the outer tube. The inner isolation film of the coaxial structure uses polytetrafluoroethylene or biodegradable film, further improving the isolation sealing and environmental friendliness. The independent sealed storage design of components A and B effectively avoids material leakage, moisture, or premature curing caused by contact with air, extending the storage life of the filament and ensuring the stability and reliability of the printing process.

[0060] Reference manual attached Figure 1-3 The extrusion stripping device includes a traction unit, a blade module, and a waste pipe recycling channel, wherein:

[0061] The traction unit includes a pair of surface-treated gears or rollers, and the material of the traction unit is aluminum alloy or stainless steel.

[0062] The blade module is made of cemented carbide or ceramic, the cutting edge angle of the blade module is 25°-35°, and the peeling length of the blade module is adjustable from 10 to 60 mm.

[0063] Waste pipe recycling channels include guide troughs and collection rolls or waste boxes.

[0064] Specifically, the transmission of the traction unit and the blade module are existing technologies, which can be achieved through gear transmission and motor drive, etc., and will not be elaborated here. The collection drum or waste box is not shown in the figure. The collection drum or waste box can be set at the outlet of the waste pipe recycling channel, and the guide groove is the waste pipe recycling channel.

[0065] Specifically, the extrusion stripping device and static mixing nozzle of this application adopt a modular structure, which can be quickly disassembled for cleaning or replacement. The outer shell of the extrusion stripping device is made of aluminum alloy main frame, and the nozzle area is made of removable and washable high temperature resistant lining. The static mixing nozzle is equipped with a cleaning channel, an air drain valve and a rinsing interface (for rinsing residues with solvent).

[0066] Specifically, the traction unit uses surface-treated aluminum alloy or stainless steel gears or rollers. The surface treatment process (hard nickel plating or rubber coating) effectively improves the gripping friction, ensuring that the hollow tubular feed filament does not slip during traction and that the feed speed is stable, thus allowing for precise control of the feed flow rate. The blade module is made of hard alloy or ceramic material, with a cutting edge angle set between 25° and 35°. This angle range ensures the cutting force during peeling while avoiding damage to the internal channel due to an overly sharp cutting edge or incomplete peeling due to an overly blunt cutting edge. The adjustable peeling length of 10–60 mm can accommodate filaments with different outer protective tube thicknesses and material hardness, improving the adaptability of the device. The guide groove and collection roll / waste box design of the waste tube recycling channel realize the centralized collection of the outer waste tube after peeling, avoiding equipment pollution or jamming caused by scattered waste tubes, ensuring a clean printing environment and continuous operation of the equipment. Therefore, the overall structural design of this application takes into account the functions of traction, peeling, and recycling, and the parameters of each component are reasonably matched, ensuring the efficiency and stability of the extrusion peeling process.

[0067] Specifically, sensors are also installed in the extrusion stripping device. Miniature flow sensors (thermal or volumetric) and pressure sensors (0–5 MPa, accuracy ±0.5%FS) are configured at the stripping and mixing inlets. The A and B flow rates are measured independently in dual channels (or calculated using proportional sensors) and fed back to the controller in real time.

[0068] Reference manual attached Figure 1 The static mixing structure of the static mixing nozzle is a multi-section spiral blade structure, a Kenics type structure, or a baffle composite structure. The number of mixing unit sections in the static mixing structure is 4-20. The nozzle orifice diameter of the static mixing nozzle is 0.2-1.0mm. The inner wall of the static mixing nozzle is provided with a DLC or PTFE anti-stick coating. The static mixing nozzle is equipped with a quick-shut-off valve to prevent dripping.

[0069] Specifically, the static mixing structure offers options for multi-section spiral blade structures, Kenics-type structures, or baffle composite structures, which can be flexibly adapted to different material viscosities and mixing requirements. The 4-20 section mixing unit design achieves high mixing uniformity under acceptable pressure drop, meeting the stringent requirements for mixing uniformity in two-component materials while avoiding excessive pressure drop and feeding difficulties caused by too many sections. The optional nozzle orifice diameter of 0.2–1.0 mm can adapt to printing needs of different precision and size, whether for fine parts or rough parts. The preform printing can cover all parts; the DLC or PTFE anti-stick coating on the inner wall effectively reduces the adhesion of two-component materials (especially highly viscous silicone and epoxy resin) to the inner wall of the nozzle, avoiding nozzle clogging caused by material residue, and facilitating subsequent cleaning; the built-in quick-shut-off valve design can quickly cut off the fluid channel when printing is paused, effectively preventing dripping, avoiding material waste and contamination of the printing path, improving the dimensional accuracy and surface quality of the printed products, and the overall structural design ensures both uniform mixing and printing flexibility and stability.

[0070] According to another aspect of this application, a method for FDM printing of two-component materials based on FDM printing technology is also provided, comprising the following steps:

[0071] S1) Connect the hollow tubular feed line containing pre-packaged liquid materials A and B to the feed channel of the FDM printer, and drive the hollow tubular feed line to feed through the traction unit of the extrusion stripping device;

[0072] S2) Using the blade module of the extrusion stripping device, the outer protective tube of the hollow tubular feeding line is cut and stripped along the axial direction of the hollow tubular feeding line, releasing the A and B components of liquid material inside the hollow tubular feeding line. The stripped waste tube is collected through the waste tube recycling channel of the extrusion stripping device.

[0073] S3) The two liquid components A and B enter the static mixing nozzle simultaneously. They are alternately sheared, layered and re-merged by the static mixing structure built into the nozzle to achieve uniform mixing.

[0074] S4) Activate the curing control module according to the material type to allow the mixed material to cure in situ during the deposition process;

[0075] S5) By using the PID closed-loop algorithm of the control system, the traction speed of the extrusion peeling device, the mixing ratio of components A and B, and the curing parameters of the curing control module are adjusted in real time to complete the printing process.

[0076] Specifically, the two-component material FDM printing method of this application achieves standardization and operability in printing two-component liquid materials through the orderly design of steps S1 to S5. Step S1, filament access and feeding, relies on the compatibility of standardized filaments with existing FDM feeding channels, requiring no additional adaptation and reducing operational difficulty. Step S2, stripping and waste tube recycling, are performed simultaneously, ensuring effective release of internal liquid material and avoiding waste tube contamination, thus improving the cleanliness and continuity of the printing process. Step S3, mixing, utilizes the alternating shearing and layering / re-merging action of a static mixing structure to ensure uniform mixing of components A and B, laying the foundation for subsequent curing. Step S4, in-situ curing, precisely matches the curing method according to the material type, ensuring thorough and efficient curing. Step S5, PID closed-loop control, effectively compensates for parameter fluctuations during the printing process by real-time adjustment of traction speed, mixing ratio, and curing parameters, ensuring consistency across all stages and avoiding molding defects caused by ratio deviations, unstable flow rates, or untimely curing. The method and process described in this application are simple and clear, which not only meets the convenience requirements of desktop applications, but also ensures the stability and reliability of print quality.

[0077] In step S1, the traction speed of the hollow tubular feeding line and the flow rate of the liquid inside the hollow tubular feeding line satisfy the following relationship: Where Q is the instantaneous flow rate and V is the traction speed of the hollow tubular feed line. The total cross-sectional area of ​​the inner channels of the hollow tubular feeding wire is used to maintain the flow ratio of components A and B at the target ratio by adjusting the traction speed of the hollow tubular feeding wire. Specifically, this application establishes... The relationship between flow rate and traction speed transforms abstract flow control into precisely adjustable traction speed control, offering ease of operation and strong controllability. Utilizing this quantitative relationship, the instantaneous flow rates of components A and B can be directly controlled by adjusting the traction speed of the hollow tubular feed filament, thereby precisely maintaining the target flow ratio of components A and B. This avoids the problem of inaccurate flow ratio control in traditional dual-pump systems. This design fully leverages the fixed cross-sectional area of ​​the hollow tubular feed filament, eliminating the need for additional complex flow adjustment mechanisms and simplifying the control logic. Simultaneously, combined with the PID closed-loop algorithm of the control system, it can correct traction speed deviations in real time, ensuring the stability of the flow ratio and ensuring consistent material properties after mixing. This effectively improves the consistency of key indicators such as mechanical properties and dimensional accuracy of printed products, making it particularly suitable for printing two-component reaction-curing materials with stringent mixing ratio requirements.

[0078] Reference manual attached Figure 1 In step S3, the nozzle section of the static mixing nozzle is divided into a mixing section, a convergence section, and an outlet section, wherein:

[0079] The mixing section is where the static mixing structure is located. The converging section is a conical transition structure with an outlet cone angle of 15°–30°. The outlet diameter of the outlet section can be selected as 0.25mm, 0.4mm, 0.6mm, 0.8mm or 1.0mm. A miniature electric heating coil is added to the nozzle orifice of the static mixing nozzle. The miniature electric heating coil adopts PID temperature control.

[0080] Specifically, the nozzle section, with its sequentially arranged mixing, converging, and exit sections, forms a rational fluid flow path. The mixing section provides a stable installation and working space for the static mixing structure, ensuring thorough mixing. The converging section employs a 15°–30° conical transition structure, effectively moderating the fluid flow velocity and reducing material stagnation and dead zones within the channel, thus avoiding problems such as uneven mixing or premature curing. Optional exit diameters of 0.25mm, 0.4mm, 0.6mm, 0.8mm, or 1.0mm can meet the needs of different printing precision and forming efficiency, adapting to diverse printing scenarios from fine structures to large-area deposition. The micro-heating coil and PID temperature control attached to the nozzle provide a precise and stable temperature environment for thermosetting materials, allowing for flexible adjustment of the curing temperature based on material characteristics. This ensures controllable curing during the deposition process, avoiding both insufficient curing and slow forming due to excessively low temperatures, and preventing material performance degradation or premature curing and nozzle clogging caused by excessively high temperatures. This significantly improves the printing quality and forming efficiency of thermosetting materials.

[0081] In step S4, the curing control module includes a thermal curing unit, a UV-LED light curing unit, and a catalytic self-curing unit, with the curing method matched according to the material characteristics:

[0082] When the material is thermosetting, the temperature is controlled at 40-150°C by using a micro heating coil at the nozzle of the static mixing nozzle in conjunction with the thermosetting unit, and a PID temperature control method to achieve curing.

[0083] When the material is photosensitive, it is cured by irradiation with 365-405nm UV-LED through a UV-LED curing unit;

[0084] When the material is chemically self-curing, the mixing ratio of components A and B and the feeding rate of the extrusion stripping device are adjusted to match the material's own reaction time to complete the curing process.

[0085] Specifically, the curing control module integrates a thermosetting unit, a UV-LED curing unit, and a catalytic self-curing unit, forming a comprehensive curing solution capable of covering various types of reaction-curing materials such as two-component liquid silicone, epoxy resin, and polyurethane. For thermosetting materials, the synergistic effect of the thermosetting unit and the nozzle's micro-heating coil, combined with PID temperature control, precisely controls the temperature between 40-150°C, ensuring a match between curing rate and curing effect, resulting in stable molding quality. For photosensitive materials, a 365-405nm wavelength UV-LED curing unit is used. This wavelength range matches the photosensitive curve of most photosensitive two-component materials, enabling rapid and efficient surface curing and improving printing efficiency. For chemically self-curing materials, the mixing ratio and feed rate are adjusted to match the material's own reaction time, eliminating the need for additional external energy consumption, making it energy-saving, environmentally friendly, and easy to operate. The precise matching design of the three curing methods ensures that different types of materials can achieve full curing, avoiding molding defects caused by incomplete or excessively rapid curing, and significantly expanding the system's application scenarios.

[0086] After printing, rinse and clean the static mixing nozzle and its built-in mixing structure:

[0087] When the printing material is washable, it is rinsed by injecting warm water through the system's solution mixing channel.

[0088] When the printing material is non-washable, flush it by injecting an appropriate solvent (such as isopropanol or a solvent specified by the manufacturer) through the system's solution mixing channel to prevent residual material from hardening and clogging.

[0089] At the same time, the flow sensor and pressure sensor configured in the control system are calibrated regularly, and worn stripping blades and nozzle components of the static mixing nozzle in the extrusion stripping device are inspected and replaced.

[0090] Specifically, this application features a design that uses warm water or a specified solvent (such as isopropanol) for rinsing depending on whether the printing material is washable. This design can thoroughly remove residual material from the static mixing nozzle and mixing structure, preventing the residual material from solidifying and clogging the channels, thus ensuring smooth subsequent printing. The system utilizes a solution mixing channel for rinsing, eliminating the need for a separate dedicated cleaning channel. This simplifies the equipment structure, reduces manufacturing costs, and is easy to operate without the need for a complex disassembly process.

[0091] Example 1: Two-component fast-setting silicone printing (for preparing sealing gaskets)

[0092] This embodiment focuses on a two-component fast-curing silicone material, with the target printed product being a high-precision sealing gasket that must meet the requirements of high dimensional accuracy, fast curing speed, and uniform mechanical properties.

[0093] The feeding line adopts a hollow tubular feeding line with a dual-channel coaxial structure and an outer diameter of φ1.75mm. The outer protective tube is made of PTFE material, and the inner isolation film is made of 50μm thick polytetrafluoroethylene. The tube is pre-encapsulated with two components, A and B, of fast-curing silicone. During the production stage, the volume ratio of A / B is set to 1:1. The two components are stored independently in sealed containers to avoid premature reaction during storage and transportation.

[0094] During printing, the filament is connected to the feed channel of the existing FDM printer. The filament is fed by the traction unit of the extrusion stripping device, with the traction speed set to 10 mm / s. The relationship between flow rate and traction speed is then established. (Where Q is the instantaneous flow rate and V is the traction speed,) (This is the total cross-sectional area of ​​the internal channels of the wire), corresponding to a total nozzle flow rate of approximately 0.2 mL / s. The control system adjusts the traction speed in real time through a PID closed-loop algorithm to ensure that the flow rate ratio error of components A / B is controlled within ±1%.

[0095] Subsequently, the blade module of the extrusion stripping device peels off the outer PTFE protective tube along the axial direction of the wire. The blade module is made of cemented carbide, with a cutting edge angle of 30° and a stripping length of 30mm. The stripped waste tube is collected and recycled through the guide groove and the collection drum to avoid contaminating the equipment and affecting the printing process.

[0096] Components A and B enter the static mixing nozzle simultaneously. This nozzle has a built-in multi-section spiral blade static mixing unit with a mixer diameter of 4mm and 8 mixing sections, totaling approximately 40mm in length. The nozzle section is divided into a mixing section, a converging section, and an outlet section. The mixing section provides a stable working space for the static mixing structure, the converging section uses a 20° conical transition structure, and the outlet section has an outlet diameter of 0.6mm. The inner wall of the nozzle is coated with a PTFE anti-stick coating. Components A and B are alternately sheared, layered, and then re-merged by the spiral blades, achieving a mixing uniformity of over 96% and effectively preventing the formation of air bubbles.

[0097] Because the material is fast-curing silicone, the curing control module activates the thermal curing unit, which, together with the miniature heating coil attached to the nozzle, precisely controls the temperature at 60°C through PID temperature control. At the same time, the UV-LED light curing unit is activated for surface-assisted curing. The wavelength of the UV-LED light curing unit is 365nm, and the exposure time is set to 1s, so as to achieve rapid in-situ curing of the mixed material and avoid flow deformation after deposition.

[0098] During the printing process, the control system coordinates the traction speed, mixing ratio, and curing temperature in real time. The final printed sealing gasket has a deposited filament width of 0.6-0.8 mm and a layer thickness of 0.3 mm. After curing, the Shore A hardness is 30, the dimensional tolerance is controlled within ±0.05 mm, and the mechanical properties are uniform, fully meeting the requirements for the use of sealing gaskets. This verifies the precise control capability and printing effect of the system in this application for fast-curing two-component materials.

[0099] Example 2: Printing of two-component epoxy potting material (adapted for electronic potting component preparation)

[0100] This embodiment focuses on a two-component epoxy potting material (slow-curing type). The target printed product is an electronic component potting part, which needs to meet the requirements of thorough mixing, complete curing, and no internal defects.

[0101] The feeding line adopts a hollow tubular feeding line with a parallel double microtube outer covering structure, with an outer diameter of φ2.85mm. The outer protective tube material is PA12, and the inner diameter of the two microtubes inside is 0.4mm. The tube is pre-encapsulated with two components of epoxy potting material, A and B. The A / B ratio can be finely adjusted through the independent traction adjustment function of the extrusion peeling device to adapt to the material reaction requirements.

[0102] During printing, the filament is connected to the feed channel of the FDM printer. The traction unit of the extrusion stripping device uses a stainless steel roller pair with rubber-coated roller surfaces to enhance gripping friction. The traction speed is adjusted to 5 mm / s according to the material viscosity (20000 mPa·s) to ensure stable feeding without slippage.

[0103] Next, the blade module peels off the outer protective tube along the wire axis. The blade module is made of ceramic material, with a cutting edge angle of 28° and a peeling length of 40mm. The peeled outer waste tube is collected through a waste box, and the internal A and B components of liquid are released smoothly without leakage or splashing.

[0104] Components A and B are simultaneously introduced into the static mixing nozzle. The static mixing structure of this nozzle adopts a Kenics type structure with 12 mixing units, a mixer diameter of 4 mm, and a total length of 60 mm, which is suitable for slow-setting materials that have higher requirements for mixing uniformity. The nozzle section is divided into a mixing section, a convergence section, and an outlet section. The convergence section adopts a 25° conical transition structure, and the outlet diameter of the outlet section is 0.8 mm. The inner wall of the nozzle is equipped with a DLC anti-stick coating. After components A and B are fully mixed by the 12 mixing units, the mixing uniformity reaches more than 97%, with no local proportional deviation.

[0105] Because the material is chemically self-curing, the mixing ratio of components A and B is adjusted to 2:1 by the control system, and the feeding rate of the extrusion and peeling device is matched to ensure that the mixed material has a suitable working time. (30 min) After printing, it will be fully cured naturally for 24 hours; if faster curing is required, the temperature can be controlled at 80°C through the heat curing unit, and the curing time can be shortened to 2 hours.

[0106] During the printing process, the control system monitors the flow rates of components A and B in real time using a flow sensor (sampling frequency 50Hz) and uses a PID closed-loop algorithm to correct for traction speed deviations, ensuring a stable mixing ratio. The final printed electronic potting compound is free of air bubbles and cracks, and after curing, it achieves a compressive strength of 35MPa and excellent insulation performance, meeting the reliability requirements for electronic component potting. This verifies the system's adaptability to slow-setting two-component materials and its precision in mixing and curing control.

[0107] The two embodiments described above cover fast-setting and slow-setting two-component reactive curing materials, respectively, which fully demonstrate the universality and reliability of the printing system and method of this application. All parameter settings and operation procedures are based on the technical solution of this application, realizing compatibility with existing FDM equipment, precise mixing and controllable curing of two-component materials, and fully meeting the diverse printing needs of desktop application scenarios.

[0108] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A two-component material printing system based on FDM printing technology, characterized in that, It includes a hollow tubular feeding line, an extrusion and stripping device, a static mixing nozzle, a curing control module, and a control system; The hollow tubular feeding line has a two-component pre-packaged structure, and the hollow tubular feeding line stores two liquid materials, A and B. The extrusion stripping device is adapted to pull the hollow tubular feeding wire and strip the outer protective tube of the hollow tubular feeding wire along the wire axis, releasing the A and B component liquid materials inside the hollow tubular feeding wire. The static mixing nozzle has a built-in static mixing structure, which is suitable for receiving the A and B components of liquid material released by the extrusion stripping device and mixing them evenly. The curing control module is adapted to perform in-situ curing of the mixed material output from the static mixing nozzle; The control system is adapted to coordinate the operation of the extrusion stripping device, the static mixing nozzle, and the curing control module to stabilize the mixing ratio, feed flow rate, and curing parameters of the A and B component liquid materials during the printing process.

2. The two-component material printing system based on FDM printing technology according to claim 1, characterized in that, The hollow tubular feeding line has a dual-channel coaxial structure or a parallel dual-microtube outer coating structure. The outer diameter of the hollow tubular feeding line is φ1.75mm or φ2.85mm. The outer protective tube material of the hollow tubular feeding line is PTFE, PA12 or PE. The inner isolation film of the coaxial structure of the hollow tubular feeding line is polytetrafluoroethylene or a biodegradable film. The A and B components inside the hollow tubular feeding line are stored independently and sealed.

3. The two-component material printing system based on FDM printing technology according to claim 1, characterized in that, The extrusion stripping device includes a traction unit, a blade module, and a waste pipe recycling channel, wherein: The traction unit includes a pair of surface-treated gears or rollers, and the material of the traction unit is aluminum alloy or stainless steel. The blade module has a blade material of cemented carbide or ceramic, a cutting edge angle of 25°-35°, and an adjustable peeling length of 10–60 mm. The waste pipe recycling channel includes a guide trough and a collection roll or waste box.

4. The two-component material printing system based on FDM printing technology according to claim 1, characterized in that, The static mixing structure of the static mixing nozzle is a multi-section spiral blade structure, a Kenics type structure, or a baffle composite structure. The number of mixing unit sections in the static mixing structure is 4-20. The nozzle orifice diameter of the static mixing nozzle is 0.2-1.0 mm. The inner wall of the static mixing nozzle is provided with a DLC or PTFE anti-stick coating. The static mixing nozzle is provided with a fast shut-off valve.

5. A method for FDM printing of two-component materials based on the system described in any one of claims 1-4, characterized in that, Includes the following steps: S1) Connect the hollow tubular feed line containing pre-packaged liquid materials A and B to the feed channel of the FDM printer, and drive the hollow tubular feed line to feed through the traction unit of the extrusion stripping device; S2) Using the blade module of the extrusion stripping device, the outer protective tube of the hollow tubular feeding line is cut and stripped along the axial direction of the hollow tubular feeding line, releasing the A and B components of liquid material inside the hollow tubular feeding line. The stripped waste tube is collected through the waste tube recycling channel of the extrusion stripping device. S3) The two liquid components A and B enter the static mixing nozzle simultaneously. They are alternately sheared, layered and re-merged by the static mixing structure built into the nozzle to achieve uniform mixing. S4) Activate the curing control module according to the material type to allow the mixed material to cure in situ during the deposition process; S5) By using the PID closed-loop algorithm of the control system, the traction speed of the extrusion peeling device, the mixing ratio of components A and B, and the curing parameters of the curing control module are adjusted in real time to complete the printing process.

6. The method for printing two-component materials based on FDM printing technology according to claim 5, characterized in that, In step S1, the traction speed of the hollow tubular feeding line and the flow rate of the liquid inside the hollow tubular feeding line satisfy a certain relationship. Where Q is the instantaneous flow rate and V is the traction speed of the hollow tubular feeding wire. The total cross-sectional area of ​​the inner channels of the hollow tubular feeding line is used to maintain the flow ratio of components A and B in accordance with the target ratio by adjusting the traction speed of the hollow tubular feeding line.

7. The method for printing two-component materials based on FDM printing technology according to claim 5, characterized in that, In step S3, the nozzle section of the static mixing nozzle is sequentially divided into a mixing section, a convergence section, and an outlet section, wherein: The mixing section is the section where the static mixing structure is located. The converging section is a conical transition structure with an outlet cone angle of 15°–30°. The outlet diameter of the outlet section can be selected as 0.25mm, 0.4mm, 0.6mm, 0.8mm or 1.0mm. A micro electric heating coil is added to the nozzle orifice of the static mixing nozzle. The micro electric heating coil adopts PID temperature control.

8. The method for printing two-component materials based on FDM printing technology according to claim 5, characterized in that, In step S4, the curing control module includes a thermal curing unit, a UV-LED light curing unit, and a catalytic self-curing unit, with the curing method matched according to the material characteristics: When the material is thermosetting, the temperature is controlled at 40-150°C by the thermosetting unit in conjunction with the miniature electric heating coil at the nozzle of the static mixing nozzle, using PID temperature control to achieve curing. When the material is photosensitive, curing is achieved by irradiation with a 365-405nm UV-LED through the UV-LED curing unit; When the material is chemically self-curing, the mixing ratio of components A and B and the feeding rate of the extrusion stripping device are adjusted to match the material's own reaction time to complete the curing process.

9. The method for printing two-component materials based on FDM printing technology according to claim 5, characterized in that, After printing, the static mixing nozzle and its built-in mixing structure are rinsed and cleaned. When the printing material is washable, warm water is injected through the solution mixing channel of the system for rinsing. When the printing material is non-washable, it is rinsed by injecting an appropriate solvent through the solution mixing channel of the system.

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