Wire rod heating intelligent 3D printing method

Abstract

The invention relates to the field of 3D printing processes, and particularly discloses a wire rod heating intelligent 3D printing method which comprises the following steps: S1, preparation: arranging a heating module between a wire rod conveying mechanism of a 3D printer and a melting unit of a printing mechanism, and configuring a temperature control module for the heating module, the heating module and the temperature control module are electrically connected with a main control system of the 3D printer; s2, feeding is conducted, specifically, a wire conveying mechanism of the 3D printer is used for conveying the wire, and the wire is guided to a printing mechanism of the 3D printer through a feeding pipe; s3, heating, wherein before the wire enters a melting unit of the printing mechanism, the external wire output by the wire conveying mechanism is heated through a heating module; and S4, temperature control is conducted, specifically, the heating power of the heating module is adjusted through the temperature control module, so that the wire reaches and maintains the preset temperature before entering the melting unit. According to the 3D printing device, immediate and accurate heating can be conducted in the wire rod conveying process, the reliability of 3D printing is remarkably improved, and the application range of materials is further expanded.

Description

Technical Field

[0001] This invention relates to the field of 3D printing technology, and in particular discloses a filament heating intelligent 3D printing method. Background Technology

[0002] In fused deposition modeling (FDM) 3D printing, the dryness of the printing filament is one of the key factors affecting the quality of the final part. If the hygroscopic filament contains too much moisture, it will undergo hydrolysis and vaporization when it melts at high temperatures in the print head, resulting in poor interlayer bonding, bubbles, scars, or material breakage on the surface, which seriously restricts the application of high-performance materials in 3D printing.

[0003] Currently, the industry commonly uses pre-treatment to dry filaments, which involves placing the entire roll of filament into a separate drying chamber or a drying hopper for several hours before use. For example, existing technologies offer various improved hopper structures that optimize internal hot air circulation to enhance drying efficiency and uniformity. However, this "dry first, use later" approach has significant drawbacks: First, the drying process is time-consuming and cannot meet the demands of instant printing; second, when the dried filament is exposed to the ambient atmosphere during transport, it quickly regains moisture, especially near the printhead where the localized high temperature creates an upward flow of hot, humid air, exacerbating the moisture regain and severely weakening the effectiveness of pre-drying; third, continuous heating of the entire roll of filament results in low energy efficiency.

[0004] To address the aforementioned issues, developing a method for real-time and precise heating and dehumidification during wire feeding is of great significance for improving the reliability of 3D printing, expanding the range of applicable materials, and achieving energy conservation and environmental protection. Summary of the Invention

[0005] In order to overcome the shortcomings and deficiencies of the existing technology, the purpose of this invention is to provide an intelligent control method for real-time preheating of the filament during 3D printing, which is particularly suitable for high-quality printing applications of multi-material, high-viscosity engineering plastics.

[0006] To achieve the above objectives, the present invention provides a wire heating intelligent 3D printing method, comprising the following steps: S1, Pre-preparation: Set up a heating module between the filament feeding mechanism and the melting unit of the printing mechanism of the 3D printer, configure a temperature control module for the heating module, and electrically connect the heating module and the temperature control module to the main control system of the 3D printer. S2, Feeding: The filament is fed using the filament feeding mechanism of the 3D printer and guided to the printing mechanism of the 3D printer through the feeding tube; S3, Heating: Before the wire enters the melting unit of the printing mechanism, the wire in the conveying state in the feeding tube is heated by the heating module; S4, Temperature control: The heating power of the heating module is adjusted by the temperature control module so that the wire reaches and maintains a preset temperature before entering the melting unit.

[0007] Furthermore, step S1 includes: S11, providing a heating element, and S12, assembling the heating element provided in step S11 to the outside of the wall of the feeding pipe.

[0008] Furthermore, the heating element set in step S11 is a conductive heating element and / or a convection heating element; When the conductive heating element is used, the wire inside the tube is heated by conducting heat from the outside to the inside through the heating of the tube wall. When the convection heating element is used, the wire is heated by introducing hot air into the feed tube and exchanging heat with the moving wire through convection.

[0009] Furthermore, the temperature control module has a processor electrically connected to the main controller of the 3D printer, and step S4 further includes: S41, the instantaneous movement speed of the print head of the printing mechanism is obtained in real time from the main controller of the 3D printer through the processor of the temperature control module; S42, using the processor, based on the instantaneous movement speed of the print head obtained in step S41, dynamically adjust the heating power of the heating module: when the print head accelerates, increase the heating power in advance; when the print head decelerates, decrease the heating power in advance.

[0010] Furthermore, the temperature control module is also equipped with a memory and an identification unit that are electrically connected to the processor. The 3D printer has a material storage mechanism and a switching mechanism that are used in conjunction with the filament feeding mechanism. The memory contains a mapping table of different filament types and their corresponding target preheating temperatures. The identification unit and the switching mechanism are both communicatively connected to the processor. The material storage mechanism includes multiple mounting positions for carrying multiple external material trays, with adjacent mounting positions used to load external material trays containing different printing filaments; the input end of the feed tube is connected to a switching mechanism, which connects the outlet of any of the mounting positions to the input end of the feed tube, allowing for free switching between different printing filaments; step S4 further includes: S411, The identification information of the currently selected external tray is read through the identification unit; S421, the processor of the temperature control module queries and retrieves the corresponding target preheating temperature from the mapping table of the memory according to the identification information; S43, the heating power of the heating module is adjusted by the temperature control module to make the wire reach the target preheating temperature and maintain the target preheating temperature.

[0011] Furthermore, the preheating in step S3 is gradient preheating, which includes: setting multiple independent heating sections along the feeding path, setting multiple heating modules, each heating module corresponding to an independent heating section, and using the heating modules to perform segmented heating of the wire in the feeding tube. In step S4, the heating power of the heating modules corresponding to each heating zone is independently adjusted by the temperature control module, so that the wire undergoes gradient preheating during the conveying process.

[0012] Furthermore, when using a convection heating element, the filament heating intelligent 3D printing method further includes step S5, venting: by setting an venting component and a heat dissipation component between the end of the feed tube and the melting unit of the external printing mechanism, the venting component draws the hot airflow from the feed tube to the heat dissipation component for heat dissipation before it reaches the melting unit, and then discharges it to the outside of the 3D printer.

[0013] Furthermore, the temperature control module has a monitoring unit for detecting the temperature of the wire heated by the heating module, and step S4 further includes: S44, the temperature control module's processor utilizes the temperature change trend of the wire fed back by the monitoring unit; S45, when the processor predicts that the wire in the feeding tube is blocked or the feeding is interrupted based on the temperature change trend, it performs the operation of reducing the heating power of the heating module or sending a warning signal to the main controller.

[0014] Furthermore, before step S2, step S13 is included: material change: the outlet of the target installation position among the multiple installation positions is connected to the input end of the feeding pipe through the switching mechanism.

[0015] Furthermore, when performing the material changing operation in step S13, step S4 includes: controlling the heating module to maintain the heating module at a preset heat preservation power through the temperature control module, so as to prevent the wire segment remaining in the feeding tube from being blocked due to excessively low temperature.

[0016] The core of this invention lies in establishing an intelligent preheating control method that works in conjunction with the 3D printing process. This method actively preheats the filament before it enters the melting unit by setting a heating module along the feeding path; and dynamically adjusts the heating power based on various real-time parameters (including material type, printhead speed, and temperature feedback trends) through a temperature control module, forming a closed-loop control. Its innovation is reflected in three levels: at the basic level, it increases the initial temperature of the filament and reduces melting resistance through conductive heating (such as heating coils) or convection heating (such as hot air); at the intelligent level, it analyzes motion trajectory data through a processor to achieve a forward-looking match between printing speed and preheating power; and at the system level, it achieves automatic switching of temperature parameters during multi-material printing through the collaboration of an identification unit, memory, and switching mechanism.

[0017] The beneficial effects of this invention are as follows: First, it further solves the clogging problem during printing with high-viscosity materials, significantly improving printing success rate and equipment reliability. Second, through speed-synchronized preheating and material-adaptive temperature control, it ensures extrusion stability at different printing stages and with different materials, effectively improving interlayer bonding and surface quality of printed parts. Finally, by utilizing temperature trend-based fault prediction and heat preservation strategies during material changeover, it constructs a self-optimizing, proactive intelligent printing environment, improving printing accuracy while reducing energy consumption and maintenance costs. Attached Figure Description

[0018] Figure 1 This is a schematic flowchart of the wire heating intelligent 3D printing method of the present invention; Figure 2 This is a detailed flowchart of step S4 in the wire heating intelligent 3D printing method of the present invention; Figure 3 This is a schematic diagram of the external structure of a 3D printer using the filament heating intelligent 3D printing method of the present invention. Figure 4 This is a partial internal schematic diagram of a 3D printer using the filament heating intelligent 3D printing method of the present invention. Figure 5 This is a three-dimensional structural diagram of the conductive heating element of the present invention after cross-section; Figure 6 This is a schematic diagram of the convection heating element of the present invention; Figure 7 This is a schematic diagram of the working process of the multi-material adaptive temperature control system in this invention.

[0019] The reference numerals in the figures include: 100. 3D printer; 200. External filament; 1. Fiber conveying mechanism; 2. Printing mechanism; 20. Print head; 3. Heating module; 4. Temperature control module; 5. Material storage mechanism; 11. Feeding pipe; 12. Main body section; 13. Heat conduction section; 14. Insulation sleeve; 21. Melting unit; 41. Conductive heating element; 411. Resistance wire; 42. Convection heating element; 421. Hot air generator; 422. Three-way valve; 43. Exhaust assembly; 51. Material tray. Detailed Implementation

[0020] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments and accompanying drawings. The content mentioned in the embodiments is not intended to limit the present invention.

[0021] Please see Figures 1 to 7 As shown, the present invention provides a filament heating intelligent 3D printing method, which includes the following steps: In the pre-preparation stage of step S1, modifications need to be made to the existing architecture of the 3D printer 100. On the feeding path between the printer's filament conveying mechanism 1 (a stepper motor-driven extruder) and the melting unit 21 of the print head (which includes a heating block and a nozzle), a section of appropriate length is selected, and the standard feed tube 11 is replaced with a specially designed composite structure heated feed tube 11.

[0022] The heating feed pipe 11 has an integrated or pre-reserved mounting position on its outer side for fixing the heating module. This module can be a resistance heating coil, a thick film heater, or an interface connected to the hot air generation system, all wrapped around the pipe. Simultaneously, a high-response temperature sensor is installed as a monitoring unit at an opening in the pipe wall adjacent to the downstream of the heating module and upstream of the melting unit 21.

[0023] Temperature control module 4 is introduced as an independent control unit, which can be a dedicated circuit board integrating a processor, power management, and communication interface. This circuit board is connected to the heating module and monitoring unit through connectors, and at the same time establishes a data connection with the main controller of 3D printer 100 through a serial communication interface (such as UART or I2C) to complete the electrical integration of the entire system.

[0024] The feeding process in step S2 is no different from traditional printing. The wire enters and passes through the heated feeding tube 11 under the push of the conveying mechanism.

[0025] Step S3, heating, is the core process of this invention. When the wire moves inside the tube, the heating module is activated, and the heat it generates continuously acts on the wire through conduction through the tube wall or hot air convection, causing its temperature to rise steadily.

[0026] Step S4, the temperature control process, is a dynamic equilibrium. The monitoring unit continuously measures the wire temperature and feeds it back to the temperature control module 4. The processor inside the temperature control module 4 compares the measured temperature with the preset target temperature, calculates the required heating power in real time by running a specific control algorithm (such as PID algorithm), and drives the power circuit to adjust the energy supply of the heating module, thereby forming a closed-loop control to ensure that the wire enters the melting unit 21 at a precise and stable temperature.

[0027] Specifically, step S11, providing the heating element, is a process of selection based on requirements. If a conductive heating element 41 is selected, the implementation options include: tightly and evenly winding a certain length of nickel-chromium resistance wire with a specific pitch around the outer wall of the metal heat-conducting section of the feed tube 11, leaving leads at both ends; or using screen printing technology to print a specially formulated conductive paste onto the outer wall of the feed tube 11 according to the designed circuit pattern, and then sintering and curing it at high temperature to form a thick film heater; or tightly winding a copper or aluminum alloy coil around the outside of the tube and connecting it to an external circulation pump and fluid heater to form a liquid thermal system.

[0028] In step S12, for wound resistance wires or coils, high-temperature resistant adhesives or metal clamps must be used to firmly fix them to the tube wall to ensure good thermal contact, and then the outside is covered with insulating and heat-insulating material. For thick film heaters, the material itself is part of the tube wall.

[0029] If convection heating element 42 is selected, the key implementation point is to connect the output port of the hot air generator (including the fan and air heater) to the feed pipe 11 via a three-way valve. The three-way valve should be installed close to the printhead end, with its first port connected to the main feed pipe 11, the second port connected to the printhead inlet, and the third port connected to the hot air source. When convection heating is activated, the three-way valve switches the air path, guiding hot air into the feed pipe 11.

[0030] The filament heating intelligent 3D printing method of this invention provides a variety of feasible heating process paths, giving the method great flexibility. Conductive heating has high efficiency and is suitable for precise temperature control; convection heating is non-contact and suitable for scenarios where materials are easily scratched or require strong dehumidification, enabling this method to adapt to diverse material and process requirements.

[0031] Specifically, as a necessary supplement to the convection heating process, an exhaust port is opened at the very end of the feed pipe 11, approximately tens of millimeters before the inlet of the melting unit 21, and connected to an exhaust pipe section. The exhaust pipe path should be designed to be away from the printhead and other heat-sensitive components, and its end is connected to a heat dissipation unit.

[0032] The heat dissipation unit can be a metal heat sink with a large surface area or an active cooling duct composed of a miniature fan. During convection heating, the hot air carrying moisture is "captured" by this exhaust port after completing its heating mission, and is guided to the heat dissipation unit through the exhaust pipe. The heat is quickly dissipated into the outside atmosphere, and the cooled airflow is exhausted. This effectively prevents hot air from interfering with the temperature field of the printhead and prevents moisture from condensing near the printhead.

[0033] As a preferred embodiment, the feed tube 11 adopts a multi-layer composite structure design, which fully considers the balance between thermal management, mechanical properties and material characteristics. The main body is made of highly flexible polyurethane or nylon material, with reinforcing fibers embedded inside to improve tensile strength, and a corrugated structure on the outer surface to increase bending flexibility, so that the feed tube 11 can easily bypass various obstacles when wiring inside the equipment, while maintaining the stability of the inner channel.

[0034] The critical heat-conducting section employs a precise multi-layered composite structure, divided into three functional layers from the inside out. The innermost layer is the liner, made of high-purity polytetrafluoroethylene (PTFE) material, formed through a special extrusion process, with its inner wall mirror-polished to achieve extremely low surface roughness. This layer has a coefficient of friction of less than 0.1 and exhibits excellent thermal stability and self-lubricating properties, maintaining stable performance over long periods at continuous operating temperatures. The middle layer is the outer structural layer, made of aerospace-grade aluminum alloy or precision-drawn stainless steel tubing, with optimized wall thickness to ensure both sufficient structural strength and excellent thermal conductivity.

[0035] The outer surface of this layer undergoes sandblasting, anodizing, or nickel plating, which enhances the contact with the heating element and improves surface wear resistance. In the conductive heating scheme, the heating element is tightly bonded to the outer structural layer using thermally conductive silicone grease or high-temperature thermally conductive adhesive, ensuring efficient heat transfer.

[0036] The outermost heat-conducting layer is the hub of heat transfer. It uses thin-walled aluminum alloy, copper, or stainless steel tubing, and is permanently bonded to the inner lining layer through interference fit or high-temperature thermally conductive adhesive, ensuring no air gaps between them and forming a low thermal resistance path from the outside to the inside. Heating elements (such as resistance coils, thick-film circuits, or liquid heating coils) are tightly and directly attached to or wrapped around the outer surface of this metal heat-conducting layer. The heat generated by these elements is quickly absorbed by the metal layer and diffused uniformly in the radial and circumferential directions, thereby providing stable and uniform heating of the wire through the inner lining layer.

[0037] This composite structure design achieves multi-functional integration. The ultra-low friction characteristics of the PTFE inner liner ensure smooth wire feeding and reduce feeding resistance, making it particularly suitable for flexible materials or long-distance feeding scenarios. Secondly, the metal structural layer not only provides the necessary mechanical support, but more importantly, it serves as an ideal heat conduction medium, enabling the rapid and uniform transfer of heat from the heating element to the entire heating zone, eliminating local overheating or underheating.

[0038] The outer insulating sleeve forms an effective thermal barrier, concentrating heat in the area requiring heating. This improves thermal efficiency, reduces energy consumption, and prevents heat diffusion from causing thermal damage to other precision components of the equipment. This synergistic design of "low friction, high thermal conductivity, and strong insulation" enables the feed tube 11 to achieve efficient utilization and precise management of thermal energy while ensuring smooth wire transport, providing a key guarantee for stable and reliable preheating effects.

[0039] Furthermore, the modular structural design facilitates maintenance and replacement; when a part is damaged, only the corresponding section of pipe needs to be replaced, reducing maintenance costs. As a preferred embodiment, the main body section and the heat-conducting section can be detachably connected using threads, snap-fit ​​mechanisms, etc. If the performance of the heat-conducting section deteriorates due to long-term use, the heat-conducting section can be replaced individually to restore its thermal conductivity.

[0040] The implementation of this invention relies on deep data interaction between the temperature control module 4 processor and the printer's main controller. Specifically, before or during printing, the temperature control module 4 processor obtains or pre-reads a G-code file from the main controller via a communication protocol. The processor internally runs an analytical algorithm to extract the printhead's motion instructions for a future time sequence, including its X, Y, and Z coordinate positions and extruder motor control signals. Through differential calculations or direct analysis, the instantaneous velocity and acceleration of the printhead at each future moment can be obtained.

[0041] Meanwhile, the processor stores a thermodynamic model of the wire delivery system. Based on this model and the predicted speed curve, the processor can calculate in advance the amount of heating power adjustment needed to match future changes in extrusion volume. For example, when the algorithm predicts that the printhead is about to perform long-distance rapid filling (high-speed movement), it will start instructing the heating module to smoothly increase the power hundreds of milliseconds in advance (this time depends on the system's thermal inertia) to accumulate enough heat to cope with high-speed extrusion when the wire reaches the melting unit 21.

[0042] This method upgrades traditional "hysteresis response" temperature control to "proactive" intelligent control, solving the inherent problem of dynamic mismatch between extrusion volume and movement speed caused by system thermal inertia in 3D printing. It significantly reduces material shortage during high-speed printing and material overflow during low-speed printing, greatly improving the accuracy and success rate of printing complex models.

[0043] Preferably, in terms of hardware, each material tray 51 is equipped with an RFID reader at its corresponding mounting position, and the material tray 51 is fitted with an RFID tag that stores a unique material ID. A multi-way valve is installed on the feeding path, with its common outlet connected to the main heating feeding pipe 11, and multiple inlets connected to each material tray 51 through sub-feeding pipes 11.

[0044] When performing the material change process, the user selects the new material through the software interface. The main controller first instructs the feeding mechanism of the currently used material tray 51 to perform a precise retraction action, pulling the end of the old wire from the shared main heating feeding pipe 11 back to the safe area of ​​its sub-feeding pipe 11. Subsequently, it drives the multi-way valve to switch and connect the path of the new material tray 51.

[0045] Simultaneously, the RFID reader on the new material tray 51 reads the tag information and uploads it to the processor in the temperature control module 4. The processor then queries the "material-parameter" mapping table in its internal memory, automatically retrieves the optimal target preheating temperature corresponding to the material, and immediately updates the controller's setpoint. Subsequently, the new material tray 51 begins feeding material, and the entire system operates under the new temperature parameters.

[0046] This method achieves intelligent and automated multi-material printing throughout the entire process, making it extremely easy for users to operate. The system can automatically identify materials and apply optimal preheating process parameters, ensuring that different materials can be printed at the most suitable temperature. This fundamentally solves the problems of poor interlayer bonding, clogging, or performance degradation caused by temperature mismatch in multi-material printing.

[0047] When the retraction action begins, the temperature control module 4 will simultaneously switch the control target of the heating module from a higher "printing temperature" to a lower "holding temperature". This holding temperature is much lower than the melting point of the material to prevent the wire from melting inside the tube, but it is sufficient to keep the wire in a soft state above the glass transition temperature to prevent it from becoming brittle and increasing in rigidity due to cooling.

[0048] This heat preservation state continues until the new material tray 51 is switched over and the new filament begins to enter the main heating feed tube 11, at which point the system will restore the temperature setting to the normal printing preheating temperature of the new material.

[0049] This insulation process effectively prevents the section of wire remaining in the main feed pipe 11 from shrinking and hardening due to temperature drop during the material change interval, thus preventing potential blockages or excessive resistance at the interface with the new wire during subsequent feeding. This ensures the absolute reliability and smoothness of the material change process.

[0050] Specifically, in a preferred embodiment, the entire heated feed pipe 11 is divided into several independent heating sections along the axial direction (e.g., three: an inlet section, a constant temperature section, and a fine-tuning section). Each section is equipped with its own independent heating element and temperature sensor, and is connected to an independent control channel on the temperature control module 4. In terms of process, the temperature control module 4 sets different but interrelated target temperatures for each section, forming a temperature gradient from low to high.

[0051] For example, the inlet zone is set to a lower temperature for initial preheating of the room-temperature wire; the constant-temperature zone is set to the core target temperature to allow the wire to fully absorb heat; and the fine-tuning zone is set to the same or slightly higher temperature as the constant-temperature zone for final calibration before exit. The temperature control module 4 uses multiple independent PID control algorithms to finely adjust the heating power of each section, making the wire travel through a gradually increasing temperature "thermal corridor" during the conveying process.

[0052] The aforementioned gradient preheating process, by decomposing the heating process, achieves precise shaping of the filament's heating path, avoiding the problems of overheating the filament surface, undercooling the core, or excessive thermal stress that may occur with intense heating in a single area. This results in extremely uniform heating inside and outside the filament, with a consistent thermal history, leading to lower internal stress, stronger interlayer bonding, and higher dimensional stability in the printed product.

[0053] During normal printing, the processor of temperature control module 4 not only focuses on the instantaneous temperature value, but also records temperature data at a certain sampling frequency and calculates its changing trend in real time (such as calculating the rate of temperature change per unit time). The processor has pre-stored or trained through machine learning to obtain the temperature curve characteristics under normal feeding conditions and the characteristic patterns of various abnormal states (such as early blockage and feeding interruption).

[0054] When the real-time monitored temperature change trend (e.g., a continuous and abnormally rapid rise in temperature may mean that the wire has stopped moving but is still being heated) matches a certain fault mode with a set threshold, the processor will immediately determine that a fault is about to occur or has already occurred, and trigger a predetermined response strategy: such as rapidly reducing the heating power to prevent carbonization, and at the same time sending a warning message containing the specific fault type and location to the main controller and user interface through the communication interface.

[0055] The above description is only a preferred embodiment of the present invention. For those skilled in the art, there will be changes in the specific implementation and application scope based on the ideas of the present invention. The content of this specification should not be construed as a limitation of the present invention.

Claims

1. A filament heating intelligent 3D printing method, characterized in that, Includes the following steps: S1, Preparatory steps: Set a heating module (3) between the filament conveying mechanism (1) and the melting unit (21) of the printing mechanism (2) of the 3D printer (100), and configure a temperature control module (4) for the heating module (3), and electrically connect the heating module (3) and the temperature control module (4) to the main control system of the 3D printer (100); S2, feeding: using the filament feeding mechanism (1) of the 3D printer (100) to feed the external filament (200) and guide it to the printing mechanism (2) of the 3D printer (100) through the feeding tube (11). S3, Heating: Before the external wire (200) enters the melting unit (21) of the printing mechanism (2), the external wire (200) output by the wire conveying mechanism (1) is heated by the heating module (3); S4, Temperature control: The heating power of the heating module (3) is adjusted by the temperature control module (4) so ​​that the external wire (200) reaches and maintains a preset temperature before entering the melting unit (21).

2. The filament heating intelligent 3D printing method according to claim 1, characterized in that, The step S1 of setting the heating module (3) includes: S11, providing a heating element and a feeding pipe (11), and using the feeding pipe (11) to guide the external wire (200) output by the wire conveying mechanism (1) to the 3D printer (100); S12, assembling the heating element provided in step S11 to the outside of the wall of the feeding pipe (11) to form the heating module (3).

3. The filament heating intelligent 3D printing method according to claim 2, characterized in that: The heating element set in step S11 is a conductive heating element (41) and / or a convection heating element (42). When the conductive heating element (41) is used, the external wire (200) inside the feed tube (11) is heated by heat conduction from the outside to the inside through the feed tube (11); When the convection heating element (42) is used, the wire is heated by introducing hot air into the feed pipe (11) and exchanging heat with the moving wire through convection.

4. The filament heating intelligent 3D printing method according to claim 3, characterized in that, When a convection heating element (42) is used, the heating intelligent 3D printing method further includes step S5, venting: by setting an venting component (43) and a heat dissipation component between the end of the feed pipe (11) and the melting unit (21) of the external printing mechanism (2), the venting component (43) draws the hot airflow from the feed pipe (11) to the heat dissipation component for heat dissipation before the hot airflow in the feed pipe (11) reaches the melting unit (21), and then discharges it to the outside of the 3D printer (100).

5. The filament heating intelligent 3D printing method according to claim 1, characterized in that, The temperature control module (4) has a processor electrically connected to the main controller of the 3D printer (100), and step S4 further includes: S41, the instantaneous movement speed of the print head of the printing mechanism (2) is obtained in real time from the main controller of the 3D printer (100) through the processor of the temperature control module (4); S42, using the processor, based on the instantaneous movement speed of the print head obtained in step S41, dynamically adjust the heating power of the heating module (3): when the print head accelerates, increase the heating power in advance; when the print head decelerates, decrease the heating power in advance; S43, the heating power of the heating module (3) is adjusted by the temperature control module (4) so ​​that the external wire (200) reaches the target preheating temperature and maintains the target preheating temperature.

6. The filament heating intelligent 3D printing method according to claim 5, characterized in that: The temperature control module (4) is configured with a memory and an identification unit that are electrically compatible with the processor. The 3D printer (100) has a material storage mechanism (5) and a switching mechanism that are used in conjunction with the filament conveying mechanism (1). The memory contains a mapping table of different filament types and their corresponding target preheating temperatures. The identification unit and the switching mechanism are both communicatively connected to the processor. The material storage mechanism (5) includes multiple mounting positions for carrying multiple external material trays (51), with adjacent mounting positions for loading external material trays (51) containing different printing filaments; the input end of the feeding tube (11) is connected to a switching mechanism, which is used to connect the outlet of any of the mounting positions to the input end of the feeding tube (11) so that different printing filaments can be freely switched; step S41 further includes: S411, the identification information of the currently selected external tray (52) is read through the identification unit; S421, the processor of the temperature control module (4) queries and calls the corresponding target preheating temperature from the mapping table of the memory according to the identification information.

7. The filament heating intelligent 3D printing method according to claim 6, characterized in that, When it is necessary to switch to different printing filaments, the process also includes step S13, material change: the material change step includes: S131, stop the current external wire (200) feeding and control the wire feeding mechanism (1) to perform a pullback action to pull the end of the current external wire (200) back from the shared section of the feeding tube (11) to its corresponding sub-feeding tube; S132, by the action of the switching mechanism, the connection between the current installation position and the input end of the feeding pipe (11) is disconnected, and the outlet of the target installation position is connected to the input end of the feeding pipe (11); S133, the wire conveying mechanism (1) corresponding to the target installation position is started to send the new external wire (200) into the feeding pipe (11).

8. The filament heating intelligent 3D printing method according to claim 7, characterized in that, When performing the material change operation in step S13, step S4 includes: controlling the heating module (3) to maintain the temperature at a preset heat preservation power through the temperature control module (4) to prevent the wire segment remaining in the feeding tube (11) from being blocked due to excessively low temperature.

9. The filament heating intelligent 3D printing method according to claim 1, characterized in that, The preheating in step S3 is gradient preheating, which includes: setting multiple independent heating sections along the feeding path, setting multiple heating modules (3), each heating module (3) corresponding to an independent heating section, and using the heating modules (3) to perform segmented heating on the external wire (200) inside the feeding tube (11); In step S4, the heating power of the heating module (3) corresponding to each heating section is independently adjusted by the temperature control module (4) so ​​that the external wire (200) undergoes gradient preheating during the transportation process.

10. The filament heating intelligent 3D printing method according to claim 1, characterized in that, The temperature control module (4) has a monitoring unit for detecting the temperature of the external wire (200) heated by the heating module (3), and step S4 further includes: S44, the temperature control module (4) processor utilizes the temperature change trend of the external wire (200) fed back by the monitoring unit; S45, when the processor predicts, based on the temperature change trend, that the wires (200) inside or outside the feeding tube (11) are blocked or the feeding is interrupted, it performs the operation of reducing the heating power of the heating module (3) or sending a warning signal to the main controller.

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