Wire rod real-time heating type intelligent 3D printing equipment

Abstract

The invention relates to the technical field of 3D printing, and particularly discloses wire real-time heating type intelligent 3D printing equipment which comprises a wire feeding mechanism and a printing mechanism, and an external wire conveyed by the wire feeding mechanism is supplied to the printing mechanism for 3D printing treatment; the device further comprises a heating module and a temperature control module used in cooperation with the heating module. The heating module is used for heating external wires output by the wire feeding mechanism, the printing mechanism is used for conducting 3D printing treatment on the external wires heated by the heating module, and the temperature control module is used for regulating and controlling the heating temperature of the heating module on the external wires. According to the invention, only the wire rod on the feeding path of the wire rod is independently heated in real time, on the basis of reducing energy consumption, the initial temperature of the wire rod before the wire rod enters the melting unit is increased, the energy and extrusion resistance required by the wire rod at the melting section are obviously reduced, the problem of blockage during printing of a high-viscosity material is avoided, and the printing efficiency is improved. And the reliability and the printing success rate of equipment are improved.

Description

Technical Field

[0001] This invention relates to the field of 3D printing technology, and in particular discloses a real-time heating intelligent 3D printing device for filaments. Background Technology

[0002] With the popularization of 3D printing technology, the requirements for print quality and material suitability are increasing. Many engineering plastics, such as nylon (PA) and polycarbonate (PC), are hygroscopic. The moisture in the filament will vaporize during high-temperature printing, leading to defects such as bubbles, stringing, and reduced strength in the printed parts. Therefore, thoroughly drying the filament before printing is a crucial step in ensuring successful printing.

[0003] In existing technologies, the most common solution is to use a separate drying silo. For example, a silo disclosed in Chinese patent CN119369717A uses a fan and heating elements to create an overall dry thermal environment within the silo to bake the trays stored inside. While this solution is effective, it has the following drawbacks: First, for filaments tightly wound on the spool, airflow struggles to penetrate the internal layers, resulting in uneven drying, with the central portion of the filament potentially remaining uncooked. Second, the spool requires continuous heating of the entire cavity, leading to significant energy consumption. More importantly, even if the filament is adequately heated in the spool, it cools again and absorbs moisture from the environment during its long journey from the spool to the printhead, severely diminishing the effectiveness of the pre-drying process, especially in high-humidity environments.

[0004] Therefore, there is an urgent need in this field for an efficient, uniform and reliable drying solution for wires to overcome the limitations of existing silo drying technologies. 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 3D printing device with filament preheating function, especially an intelligent system that can accurately and in real time heat the filament before it enters the melting unit of the print head, and adapt to the printing needs of multiple materials and multiple colors.

[0006] To achieve the above objectives, the present invention provides a real-time filament heating intelligent 3D printing device, comprising a filament feeding mechanism, a printing mechanism, and a feeding pipe for guiding the filament fed by the filament feeding mechanism to the printing mechanism; further comprising a heating module disposed on the feeding path of the feeding pipe, a temperature control module used in conjunction with the heating module, and a detection module; the heating module is located upstream of the melting unit of the printing mechanism for heating the filament before it enters the melting unit; the detection module is electrically connected to the temperature control module, the detection module is used to detect the temperature data of the filament heated by the heating module and transmit it to the temperature control module; the temperature control module is used to adjust the heating power of the heating module according to preset parameters or the temperature information fed back by the detection module in real time, so as to regulate the preheating temperature of the filament.

[0007] Furthermore, the heating module is a conductive heating unit and / or a convection heating unit. The conductive heating unit includes a heating element sleeved on the outside of the feeding pipe. The heating element heats the pipe wall of the feeding pipe to conduct heat to the wire inside the feeding pipe.

[0008] Furthermore, the heating element is a resistance heating coil, a liquid-thermal spiral coil, or a thick-film electric heater that is spirally wound around the outside of the feeding tube; the liquid-thermal spiral coil is wound around the outside of the feeding tube, and a heat-conducting fluid heated by an external heating unit flows inside it, conducting heat to the feeding tube through fluid circulation; the thick-film electric heater is formed on the outer surface of the feeding tube wall through a printing and sintering process, and its thick-film circuit is configured to uniformly heat the feeding tube; the resistance heating coil is a flexible heating film that is spirally wound around the outside of the feeding tube or attached to the outer wall of the feeding tube.

[0009] Furthermore, the convection heating unit includes a hot air generator for generating hot airflow and a three-way valve that communicates with the feeding pipe. The three-way valve has a first interface, a second interface, and a third interface that are interconnected. The first interface communicates with the output end of the feeding pipe, the second interface communicates with the inlet of the printing mechanism, and the third interface communicates with the hot air outlet of the hot air generator. The hot airflow generated by the hot air generator is introduced into the feeding pipe through the third interface of the three-way valve and undergoes convection heat exchange with the wire flowing through the feeding pipe.

[0010] Furthermore, the hot air generator includes a fan and a heater. The direction of the hot air flow is intersected with the direction of the wire conveying. The heater is located between the air outlet of the fan and the third port of the three-way valve. The air flow generated by the fan is heated by the heater to form a hot air flow, which is then introduced into the feeding pipe through the third port.

[0011] Furthermore, the intelligent 3D printing equipment also includes an exhaust assembly located at the end of the feed pipe. The exhaust assembly includes an exhaust pipe communicating with the inner cavity of the feed pipe and a heat dissipation unit located at the end of the exhaust pipe. The hot air flow introduced into the feed pipe by the hot air generator is discharged to the heat dissipation unit via the exhaust pipe before reaching the melting unit of the printing mechanism, and then discharged to the outside of the intelligent 3D printing equipment.

[0012] Furthermore, the detection module is a temperature sensor, which is installed between the heating module and the melting unit of the external printing mechanism to collect the temperature of the filament heated by the heating module in real time. The temperature control module also includes a processor, which is electrically connected to the main controller of the 3D printing equipment. The real-time temperature data of the filament collected by the temperature sensor is fed back to the processor. The processor is configured to: determine the conveying status of the filament in the feed tube based on the temperature change trend of the filament, and predict when a feed blockage or interruption will occur, and send a warning signal to the main controller or reduce the heating power of the heating module.

[0013] Furthermore, the temperature control module is electrically integrated with the main controller of the 3D printing equipment. The temperature control module pre-reads or acquires the motion trajectory planning data of the printing mechanism in real time. The temperature control module is configured to adjust the heating power of the heating module in advance according to the instantaneous movement speed of the print head of the printing mechanism in the motion trajectory data, so that the heating power is increased in advance when the print head accelerates and decreased in advance when the print head decelerates.

[0014] Furthermore, the feeding pipe has a main body section and a heat-conducting section. The heat-conducting section includes an inner liner made of a high-temperature resistant polymer material and a heat-conducting layer made of a metal material, with the heat-conducting layer covering the outside of the inner liner.

[0015] Furthermore, the intelligent 3D printing equipment also includes a material storage mechanism and a switching mechanism used in conjunction with the filament feeding mechanism. The material storage mechanism includes a support and mounting positions on the support for carrying material trays. There are multiple mounting positions, and two adjacent mounting positions are used to load material trays containing different printing filaments. The input end of the feeding tube is connected to the switching mechanism, which is used to connect the outlet of any of the mounting positions to the input end of the feeding tube, so that different printing filaments can be switched freely.

[0016] Furthermore, the heating module includes multiple independent heating sections distributed along the feeding path, and the heating source of each heating section is independently electrically connected to the temperature control module; the temperature control module is configured to independently adjust the heating power of each heating section according to the wire type and conveying speed through a PID control algorithm to achieve gradient preheating of the wire in the feeding tube.

[0017] Furthermore, each of the multiple mounting positions is equipped with an identification unit for reading the identification information of the material tray carried thereon; the temperature control module includes a memory and a processor, the memory pre-stores a mapping table of different wire types and their corresponding target preheating temperatures; the identification unit and the switching mechanism are both communicatively connected to the processor; The processor is configured to: Based on the selection state of the switching mechanism, the identification information read by the identification unit on the corresponding installation position is obtained; Based on the identification information, the corresponding target preheating temperature is queried and retrieved from the mapping table; The heating power of the heating module is adjusted in real time according to the target preheating temperature.

[0018] Furthermore, the switching mechanism is a multi-way valve, which has a common outlet and multiple selectable inlets; the common outlet is connected to the input end of the feed pipe, and the multiple selectable inlets are respectively connected to the corresponding installation positions through independent sub-feed pipes; the heating module is configured to heat the shared feed pipe downstream of the common outlet.

[0019] Furthermore, the temperature control module is configured to control the heating module to maintain a set heat preservation power during the material changing operation to prevent the wire segment remaining in the feeding tube from becoming too cold and causing blockage; and / or, the switching mechanism is linked with the wire feeding mechanism and is configured to perform a retraction action before cutting off the current material tray supply, retracting the end of the current wire from the high-temperature shared feeding tube segment to its corresponding sub-feeding tube.

[0020] Furthermore, the temperature control module is equipped with an over-temperature protection circuit. When the detection unit detects that the wire temperature exceeds the safety threshold, the temperature control module automatically cuts off the power supply to the heating module and sends an abnormal signal to the main controller to prevent the wire from overheating and carbonizing or the feeding tube from being damaged.

[0021] The present invention provides a real-time filament heating intelligent 3D printing device. Its core principle lies in the integration of a collaborative preheating system, consisting of a heating module, a detection module, and a temperature control module, along the feed pipe path upstream of the melting unit of the printing mechanism. This system actively preheats the conveyed filament through conductive heating (such as heating coils) and / or convection heating (such as hot air). The temperature control module dynamically adjusts the heating power based on real-time feedback data from temperature sensors or preset programs (such as material type and printing speed), achieving precise closed-loop control of the preheating temperature.

[0022] The beneficial effects of this invention are as follows: First, by increasing the initial temperature of the wire before it enters the melting unit, the energy required in the melting section and the extrusion resistance are significantly reduced, thus avoiding the clogging problem when printing high-viscosity materials and improving the reliability of the equipment and the printing success rate.

[0023] Secondly, by intelligently linking the preheating system with the multi-tray material changing mechanism, the equipment can automatically identify the material type and call the corresponding optimal preheating temperature, realizing "material-specific heating" in the multi-material printing process, ensuring the consistency of printing quality and interlayer bonding of various parts of complex models.

[0024] Thirdly, by leveraging the forward-looking temperature control based on the printing motion trajectory and the material blockage prediction algorithm based on temperature change trends, the system has achieved a leap from passive response to active adaptation. This not only perfectly matches the extrusion volume with the printing speed and reduces stringing and material shortage, but also provides fault warning capabilities, thus building an efficient, stable, and intelligent 3D printing platform. Attached Figure Description

[0025] Figure 1 This is a three-dimensional structural diagram of the real-time heating intelligent 3D printing device of the present invention when the front cover is removed. Figure 2 This is a schematic diagram showing the location of the heating module in the real-time heating intelligent 3D printing device of the present invention. Figure 3 This is a three-dimensional structural diagram of the real-time heating intelligent 3D printing device of the present invention when the top cover is removed. Figure 4 This is a schematic diagram of the material storage mechanism of the present invention; Figure 5 This is a three-dimensional structural schematic diagram of the conductive heating unit of the present invention; Figure 6 This is a three-dimensional structural diagram of the conductive heating unit of the present invention after cross-section; Figure 7 This is a three-dimensional structural diagram of the feed tube of the present invention after being cut open; Figure 8 This is a three-dimensional structural schematic diagram of the convection heating unit of the present invention; Figure 9 This is a partial flowchart of the real-time heating intelligent 3D printing device of the present invention.

[0026] The reference numerals in the figures include: 100. Chassis; 200. External wires; 1. Wire feeding mechanism; 2. Printing mechanism; 3. Feeding pipe; 4. Heating module; 5. Temperature control module; 6. Detection module; 7. Material storage mechanism; 8. Switching mechanism; 20. Print head; 21. Melting unit; 31. Main body section; 32. Heat-conducting section; 321. Inner lining layer; 322. Heat-conducting layer; 33. Insulation sleeve; 41. Conductive heating unit; 411. Resistance heating coil; 42. Convection heating unit; 421. Hot air generator; 422. Three-way valve; 423. First interface; 424. Second interface; 425. Third interface; 431. Exhaust pipe; 71. Bracket; 72. Mounting position; 73. Material tray. Detailed Implementation

[0027] 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.

[0028] Please see Figures 1 to 9 As shown, this invention provides a real-time filament heating intelligent 3D printing device, including a chassis, a filament feeding mechanism and a printing mechanism disposed within the chassis, and a feeding tube for guiding external filament 200 conveyed by the filament feeding mechanism to the printing mechanism. To solve the problem of cooling and moisture absorption during the transportation of traditional printing filaments, the device is equipped with a heating module, a detection module, and a temperature control module along the filament conveying path inside the feeding tube. The heating module is arranged upstream of the melting unit of the printing mechanism along the filament movement direction, ensuring that the external filament 200 is sufficiently preheated before entering the melting zone. The detection module collects the temperature of the external filament 200 in real time and transmits the signal to the temperature control module. The temperature control module dynamically adjusts the heating power according to preset parameters or real-time temperature feedback, achieving precise heating control of the external filament 200. This basic architecture ensures that the external filament 200 maintains an optimal temperature state before entering the melting unit, effectively avoiding a series of printing quality problems caused by heat loss during filament transportation in traditional solutions.

[0029] In the preferred structure, the wire feeding mechanism can employ a stepper motor-driven gear extrusion structure, mounted on the upper part of the printing equipment. The feeding roller and pressure roller cooperate to clamp the external wire 200. One end of the feeding tube is connected to the outlet of the feeding mechanism, and the other end is connected to the inlet of the printing mechanism, forming a closed feeding channel. The feeding tube is preferably a cylindrical structure with an inner diameter slightly larger than the wire diameter to ensure smooth wire sliding and avoid friction jamming. This precise mechanical fit ensures the stability and continuity of wire feeding, providing a reliable material feeding foundation for subsequent heat treatment.

[0030] Specifically, the heating module includes a conductive heating unit and / or a convection heating unit. The conductive heating unit is preferably installed on the outer wall of the feed tube, employing a spiral winding or attached structure. In one specific embodiment, the heating module is a resistance heating coil, made of high-temperature resistant nickel-chromium alloy wire, spirally and evenly wound on the outer wall of the feed tube, transferring heat to the wire inside the feed tube through a thermally conductive metal layer. A heat-insulating sleeve is wrapped around the coil; this sleeve is made of multi-layer composite material, with an inner reflective film, a middle aerogel insulation layer, and an outer high-temperature resistant silicone layer, forming an effective thermal barrier. Compared to traditional heating methods, this structure significantly improves thermal efficiency, reduces energy loss, and prevents thermal impact on other components of the equipment.

[0031] In another embodiment, a thick-film electric heater can be used, whose conductor circuit is screen-printed and sintered at high temperature onto the outer surface of the feed tube. The thick-film circuit adopts a segmented design, with each segment capable of independent temperature control. Optimized circuit layout results in more uniform heat distribution. The heater surface is also covered with a protective glaze layer, improving corrosion resistance and mechanical strength. This design achieves rapid thermal response and precise temperature control, making it particularly suitable for high-performance material printing scenarios requiring high temperature uniformity, effectively avoiding localized overheating or underheating.

[0032] In addition, the heating module can also be a liquid-thermal spiral coil, with a heat-conducting fluid heated by an independent heating unit circulating inside. The system includes a storage tank, a circulation pump, a heater, and a temperature sensor, forming a complete closed-loop control system. The coil is made of a high thermal conductivity metal material and fits tightly against the outer wall of the feed tube, with optimized flow channel design ensuring uniform heat transfer. Compared to direct electric heating solutions, the liquid-thermal system offers better temperature stability and thermal inertia, effectively suppressing temperature fluctuations and providing a continuous and stable heating environment for the filament, making it particularly suitable for applications requiring long-term constant-temperature printing.

[0033] Specifically, the second option is a convection heating unit. This unit operates independently of or in conjunction with the conduction heating unit. Its implementation hinges on a three-way valve and a hot air generator. The preferred three-way valve is an electromagnetically driven two-position three-way valve. The valve body is made of high-temperature resistant engineering plastic, and the internal seals use fluororubber to ensure long-term reliability in high-temperature environments. Its first interface connects to the output end of the feed tube via a high-temperature resistant silicone or PTFE hose, with a quick-release structure for easy maintenance. The second interface connects to the printhead inlet in the same manner. The third interface connects to the outlet of the hot air generator, and each interface is designed to prevent misconnection.

[0034] The hot air generator consists of a miniature centrifugal fan and a cylindrical heating wire. The heating wire uses a positive temperature coefficient material and has self-limiting temperature characteristics, improving system safety. A flow equalization device is installed between the fan and the heater to ensure uniform airflow distribution. The heater is externally covered with multiple layers of insulation material, significantly reducing heat loss. To ensure that the hot air does not affect the temperature field of the melting unit, an exhaust branch pipe is installed at the end of the feed pipe and upstream of the melting unit inlet. This branch pipe adopts a gradually expanding design to reduce the airflow velocity, and its end connects to an air collection box equipped with aluminum heat sink fins. A small exhaust fan then discharges the cooled airflow outside the equipment. This complete hot air circulation path design ensures heating effect while avoiding interference with the printhead's working environment.

[0035] In actual operation, the hot airflow flows along the channel of the external wire 200 and undergoes convective heat transfer with the external wire 200. To create a vortex in the hot airflow within the pipe to improve heat exchange efficiency, the interface between the three-way valve and the feed pipe adopts a Venturi structure design, with guide vanes at the inlet to ensure that the direction of the hot airflow forms a specific angle (e.g., 30°-60°) with the conveying direction of the external wire 200, generating a rotating airflow field within the pipe. This design significantly enhances the heat exchange efficiency between the airflow and the surface of the external wire 200, while effectively removing volatile substances precipitated on the surface of the external wire 200, keeping the wire surface clean.

[0036] Preferably, an exhaust assembly is connected downstream of the hot air generator. This assembly includes an exhaust pipe and a heat dissipation unit at its end. The exhaust pipe is made of corrugated metal and has a degree of flexibility to adapt to equipment layout requirements. The heat dissipation unit uses a combination of aluminum heat sink fins and a micro fan. The fin surface is anodized to enhance heat dissipation, and the fan speed can be automatically adjusted according to the detected exhaust temperature. This intelligent heat dissipation design ensures that the exhaust temperature is always kept within a safe range while optimizing system energy consumption.

[0037] Furthermore, in actual manufacturing, this invention also provides the following two technical solutions: The first solution involves setting micro-heat-conducting fins on the inner wall of the feeding pipe. The fins are distributed in a spiral pattern, which increases the heat exchange area and also guides the wire. When using convection heating, the fins can disrupt the boundary layer and enhance the turbulence effect; when using conduction heating, the fins increase the heat conduction path and improve the uniformity of heat. This innovative structure significantly improves heat exchange efficiency without increasing system complexity.

[0038] The second approach involves introducing an adaptive control algorithm based on material properties into the temperature control module. After acquiring material information through the identification unit, the system not only retrieves preset temperature parameters but also automatically optimizes PID control parameters and look-ahead control strategies based on the material's physical properties such as heat capacity and thermal conductivity. For example, for materials with high heat capacity, the system will appropriately increase the heating power and extend the preheating time; for materials with poor thermal conductivity, the system will adopt a smoother heating curve. This intelligent control method further enhances the system's adaptability and control accuracy.

[0039] Specifically, the core hardware of the temperature control module is an embedded microprocessor. This processor needs to have a sufficiently fast computing speed to handle complex control algorithms, for example, using a chip based on an ARM Cortex-M4 or a higher-performance core. Its peripheral circuitry includes a multi-channel high-precision analog-to-digital converter (ADC) for real-time acquisition of analog voltage signals from the detection module—a K-type thermocouple or NTC thermistor precisely attached to the surface of the wire at the feed tube outlet or pressed against the tube wall by a miniature spring mechanism. Simultaneously, the processor is equipped with multiple high-resolution PWM output channels to drive the subsequent power regulation circuitry.

[0040] The power regulation circuitry varies depending on the type of heating element: for resistive heating coils and thick-film electric heaters, switching circuits composed of MOSFETs or IGBTs are used to regulate the effective voltage; for the heating wire in the hot air generator, solid-state relays or MOSFETs are also used for on / off control; for liquid-thermal systems, heat flow is managed by adjusting the speed of the circulating pump motor and the input power of the PTC heater. All these circuits are integrated on a compact PCB (printed circuit board) and equipped with necessary filtering, protection, and isolation components to ensure stable operation in the complex electromagnetic environment of a 3D printer.

[0041] This hardware architecture, based on a high-performance microprocessor, provides a solid physical foundation for achieving precise, fast, and stable temperature control. Multiple independent signal acquisition and power output channels enable the system to control multiple heating zones and different types of heating elements simultaneously or separately, offering great flexibility and scalability while ensuring control accuracy and system reliability.

[0042] The processor operates a sophisticated digital PID (Proportional-Integral-Derivative) control algorithm. This algorithm is specifically optimized to handle the inertia of the feed tube thermal system. The proportional term (P) responds quickly to current temperature errors; the integral term (I) eliminates steady-state errors, ensuring long-term accuracy; and the derivative term (D) makes predictive adjustments based on temperature trends, suppressing overshoot. The PID parameters (Kp, Ki, Kd) are not fixed but can be self-tuned online or retrieved from a pre-stored parameter table based on different wire types, target temperatures, and actual heating rates to adapt to varying dynamic characteristics. The processor executes this control cycle at fixed short intervals (e.g., 100 times per second), calculating the required control input and ultimately converting it into a PWM signal duty cycle or analog output, achieving microsecond-level fine-tuning of the heating power.

[0043] Specifically, the temperature control module's processor connects to the 3D printer's main controller via UART or I2C communication protocols, enabling it to pre-read or acquire real-time motion trajectory planning data of the print head. Based on this, it executes a proactive temperature control strategy: before the printing task begins, the temperature control module requests and pre-reads the G-code file for the entire printing task. A dedicated parsing program runs in the processor, proactively analyzing the motion trajectory over the next few seconds or even longer, accurately calculating the print head's instantaneous velocity, acceleration, and the extruder's theoretical extrusion speed at each moment. Based on this data and the built-in material thermophysics model, the control algorithm generates a dynamic target temperature curve that is completely synchronized with it.

[0044] For example, when the algorithm predicts that the printhead will accelerate during high-speed filling motion, it will instruct the heating module to moderately and smoothly increase its power hundreds of milliseconds in advance (this advance amount is precisely calculated based on the system's thermal inertia) to ensure that there is enough heat to maintain the suddenly increased filament extrusion rate during acceleration, and to prevent weak extrusion or material shortage due to insufficient material melting.

[0045] This forward-looking temperature control strategy, deeply coupled with the motion trajectory, is the embodiment of the invention's intelligence. It breaks away from traditional static or simple feedback temperature control modes, achieving a feedforward-oriented, proactive temperature control that precisely matches the printing behavior by pre-reading motion planning data. This solves the industry problem of dynamic mismatch between extrusion volume and printing speed caused by system thermal inertia, effectively eliminating common phenomena such as stringing, material accumulation, or uneven interlayer bonding at speed abrupt changes, significantly improving print yield and surface quality.

[0046] In actual operation: The processor continuously reads the real-time temperature of the wire from the temperature sensor, compares it with the target preheating temperature, and then dynamically adjusts the PWM duty cycle output to the heating element through the PID control algorithm (for liquid heating systems, it controls the circulating pump and PTC heater), forming a precise closed-loop control to stabilize the wire temperature near the target value, with fluctuations controlled within the industry-recognized ±1.5°C.

[0047] During material changeover, the system executes a sophisticated coordinated control sequence. When the user initiates a material changeover command, the main controller first notifies the temperature control module. The processor then instructs the feeding mechanism of the current tray to perform a precise retraction action, accurately pulling the end of the current color wire from the high-temperature shared feeding tube section back into its corresponding unheated sub-feeding tube, preventing the end from remaining in the high-temperature zone and undergoing baking and degradation. Immediately afterwards, the processor drives the motor or solenoid of the multi-way valve to switch the path to the target tray.

[0048] Simultaneously, the RFID reader on the material tray mounting position is activated, reading the material identification information from the electronic tag embedded in the tray. Upon receiving this information, the processor immediately queries the pre-stored "material-parameter" mapping table in its non-volatile memory and automatically retrieves the corresponding optimal target preheating temperature, PID parameters, and even look-ahead control coefficients. The entire material changeover and temperature strategy switching process is completed within seconds, seamlessly integrated, and requires no manual intervention.

[0049] In addition, the processor runs an intelligent diagnostic algorithm based on big data. It continuously monitors and records the temperature sensor readings. Under normal and smooth feeding conditions, the temperature curve fluctuates smoothly around the set value. Once signs of feeding blockage appear, the wire movement speed slows down or even stops, and the time it is continuously heated increases. The temperature sensor will detect an abnormal, continuous, and rapidly rising slope of the temperature curve.

[0050] When the diagnostic algorithm identifies this characteristic pattern, the system can issue a warning before complete blockage and automatically execute protective operations, such as significantly reducing or even cutting off the heating power, while sending clear fault information to the main controller and user interface. Similarly, if a feeding interruption occurs, the sensors will detect a sudden drop in temperature caused by the influx of cold wire, and the system will immediately take corresponding measures.

[0051] Through the above-described specific embodiments, this invention changes the physical state of the filament before it enters the melting unit. By precisely and controllably preheating, it significantly reduces the melting resistance of high-viscosity engineering plastics (such as PA and PC), effectively avoiding common faults such as feeding slippage, insufficient extrusion, and nozzle clogging, thereby greatly improving the reliability and success rate of the printing process.

[0052] In addition, the intelligent preheating system, through linkage with the motion planning at the front, achieves precise dynamic matching between extrusion volume and printing speed, effectively reducing defects such as stringing and material shortage caused by temperature lag, resulting in a smoother surface quality, more refined details, and stronger interlayer bonding of the printed model.

[0053] Compared to traditional drying hoppers that require continuous heating of the entire chamber, this invention only provides localized, directional heating to the conveying filament, significantly reducing energy consumption and aligning with the principles of green manufacturing. Finally, its highly automated multi-material identification and temperature control switching functions simplify user operations, making the printing of complex multi-color or multi-functional materials simple and reliable, expanding the equipment's application range, and providing users with an unprecedentedly convenient experience and high-quality print output.

[0054] As a preferred embodiment, the feed tube 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. This allows the feed tube to easily bypass various obstacles when wiring inside the equipment, while maintaining the stability of the internal channel.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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 to achieve efficient utilization and precise management of thermal energy while ensuring smooth wire transport, providing a key guarantee for stable and reliable preheating results.

[0060] 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.

[0061] To further optimize the uniformity and controllability of the heating process, the heating module adopts a segmented and refined design. Specifically, along the axial direction of the feeding pipe, the entire heating area is precisely divided into three independent heating sections: the inlet zone, the constant temperature zone, and the fine-tuning zone.

[0062] The inlet section is located near the wire feeding mechanism. This section is equipped with heating elements of relatively high power density, whose primary task is to achieve rapid, initial heating of the wire. The temperature sensor in this section is installed relatively forward to monitor the initial heating rate of the wire. The temperature control module sets a relatively low target temperature for this section, and its control strategy emphasizes rapid response. The proportional term coefficient in the PID algorithm is set relatively high to quickly raise the room-temperature wire to a basic preheating temperature.

[0063] The constant-temperature zone, following the inlet zone, is the longest section and the core area for wire preheating. The heating elements in this zone prioritize extreme temperature uniformity, employing techniques such as thick-film heating to ensure consistent heat distribution along the circumferential and axial directions of the tube wall. Temperature sensors are installed in the middle to rear of this zone to monitor the wire's steady-state temperature. The temperature control module sets a core preheating temperature for this zone. The control algorithm emphasizes stability, with a prominent integral term to eliminate steady-state errors and maintain the wire temperature precisely near the target value for an extended period, completing the core heat absorption process.

[0064] The fine-tuning zone, located closest to the fusion unit of the printhead, is a crucial area for the final temperature calibration of the filament before it exits the fusion unit. Although short, this section requires the highest control precision. Its heating element must respond extremely quickly, and it is equipped with a highly sensitive temperature sensor installed close to the feed tube exit to obtain the most accurate filament exit temperature. The temperature control module sets the target temperature for this section to be the same as that of the constant-temperature zone or finely adjusted according to material characteristics (such as slightly compensating for heat loss in the inlet area). Its control algorithm is highly sensitive, with the differential term amplified, enabling it to quickly suppress any temperature fluctuations and ensure that the filament temperature entering the fusion unit is highly accurate and stable.

[0065] These three temperature control modules can be physically independent controllers, or they can be three independent control threads within the same main processor. They work together through internal communication. The actual temperature of the inlet zone can serve as a feedforward signal for the constant temperature zone, and the stability of the constant temperature zone lays the foundation for precise fine-tuning in the fine-tuning zone.

[0066] This multi-segment independently controlled gradient preheating scheme offers several significant advantages. By simulating an ideal heat treatment curve, it subjects the wire to a process of "slow heating-steady holding-precise calibration," avoiding the localized overheating and thermal hysteresis problems that are difficult to solve with single-zone heating, resulting in more uniform heating inside and outside the wire. It decomposes a complex, high-inertia heating system into multiple smaller, more easily controlled subsystems, greatly improving the system's control accuracy and response speed, and enabling the wire's final outlet temperature control accuracy to reach a new level.

[0067] Furthermore, this structure allows for flexible setting of gradient curves for different material properties. For example, a gentler heating gradient can be used for heat-sensitive materials, while the power in the inlet region can be increased for high-melting-point materials, demonstrating excellent process adaptability. Ultimately, this design significantly improves print quality, reducing defects such as extrusion instability, weak interlayer bonding, and excessive internal stress in the model caused by uneven or fluctuating temperatures at the source.

[0068] Specifically, the intelligent 3D printing equipment also includes a material storage mechanism and a switching mechanism. The core of the material storage mechanism is a rigid metal bracket, which is mounted on the printer's main frame via shock-absorbing pads to isolate vibrations generated by the print head's movement. The bracket has multiple mounting positions, each containing a freely rotatable load-bearing shaft to support the material tray; a spring-loaded friction brake to prevent excessive rotation of the material tray due to inertia; and a filament guide ring to ensure that the filament enters the sub-feed tube (not shown in the diagram, located between mounting position 72 and switching mechanism 8) at a constant angle when unwinding from the material tray, preventing tangling. Each mounting position is structurally independent and has ample space for easy loading and unloading of the material tray.

[0069] Each mounting position is equipped with an independent identification unit, and in the preferred embodiment, a low-frequency RFID system is used. A passive RFID tag containing a unique ID and material type information is embedded in the hub of each tray. A miniature RFID reader is fixed to the base of the mounting position, and its reading distance is precisely calibrated to ensure that it can only be identified when the tray is installed in place, avoiding misreading of adjacent trays.

[0070] As an alternative, a miniature CMOS camera can be used to scan the QR codes or color identification codes on the tray. This solution requires a ring-shaped LED supplementary light at the mounting location to ensure stable reading under various lighting conditions. The identification unit communicates with the main controller via IO-Link or a simple digital interface.

[0071] The switching mechanism is located between the outlet of each installation position and the input end of the main feed pipe. Its core function is to establish a leak-free, low-resistance, controllable material path. In this embodiment, a multi-way valve is preferred, with its body made of wear-resistant engineering plastics (such as PEEK) or brass. The valve core employs a conical sealing design and is driven by a small stepper motor for rotation or linear motion to ensure accurate positioning and reliable sealing. The common outlet is connected to the input end of the main feed pipe via a quick-connect fitting with a locking ring. Each selected inlet is connected to the outlet of the corresponding tray via a flexible sub-feed pipe (such as a PTFE pipe). All interfaces are designed with foolproof features to prevent misconnection.

[0072] When a user selects a material in the printing software, the main controller sends a pulse or level signal to the multi-way valve's driver, actuating the valve core to precisely align the selected inlet and common outlet of the target material tray. The entire switching process is accompanied by feedback from position sensors (such as Hall effect sensors or photoelectric switches) to ensure the valve core is in position. Simultaneously, the temperature control module receives material switching commands from the main controller via the communication bus or directly obtains new material information from the identification unit.

[0073] To prevent residual wire from clogging during switching, the system executes a precise coordinated control sequence before the switching operation. The specific process is as follows: The main controller sends a command to the feeding motor of the currently used tray to perform a precise retraction action. This retraction distance is calculated in advance based on the length of the shared feeding tube section and the wire diameter, ensuring that the end of the current wire is pulled back precisely from the high-temperature shared feeding tube section to its corresponding unheated sub-feeding tube "safe zone".

[0074] Next, as the retraction action begins, the temperature control module immediately adjusts the power setpoint of the heating module to a lower "heat preservation power". The target temperature of this heat preservation power is much lower than the glass transition temperature or melting point of the material, but sufficient to prevent the wire from cooling and becoming brittle due to ambient temperature, thereby ensuring that the small amount of wire remaining at the junction of the wire path maintains a certain degree of toughness and will not break or increase the subsequent feeding resistance.

[0075] After this preparatory step is completed, the multi-way valve will switch. Once the path to the new material tray is open, its feeding mechanism will push the new wire into the main feeding pipe, and at the same time, the heating module power will quickly return to the target preheating temperature corresponding to the new material.

[0076] Preferably, the temperature control module also includes an independent and redundant over-temperature protection circuit. This circuit is designed independently of the main CPU's temperature control loop, ensuring effective protection even in the worst-case scenario of a main processor program crashing or freezing. Its core is a hardware comparator circuit (such as the LM339 series). One input of this comparator is connected to a fixed reference voltage generated by a precision voltage regulator and set through a resistor divider network. This voltage corresponds to the system's preset maximum safe temperature threshold (e.g., for common engineering plastics, it can be set to the thermocouple millivolt value corresponding to 280°C). The other input of the comparator is directly connected in parallel to the signal line of the detection module (thermocouple or thermistor) to acquire the raw analog signal from the temperature sensor in real time.

[0077] When the detection module detects that the temperature of the wire or heating zone exceeds the safety threshold, the hardware comparator will react within microseconds, and its output state will immediately flip. This flip signal is sent to two paths simultaneously: The first path directly controls the gate of a solid-state relay or a high-power MOSFET, immediately and physically cutting off the main power supply circuit to the heating module (whether it is a resistance coil, a thick-film circuit, or a heating wire in a hot air generator), achieving the fastest hardware-level power-off.

[0078] The second path sends an interrupt to the main processor's non-maskable interrupt pin, forcing the CPU to interrupt any current task and prioritize handling this emergency.

[0079] Subsequently, the temperature control module sends an exception signal containing a specific error code to the main controller via the communication interface. This communication is not just a simple alarm, but a structured data packet transmitted via a reliable protocol such as CAN bus or UART.

[0080] The data packet not only contains the "over-temperature" status bit, but also records the precise timestamp when the over-temperature occurred, which heating section triggered the protection, the temperature change trend before the trigger, and the software status of the main control CPU.

[0081] Upon receiving this signal, the main controller will take a series of escalation measures: First, it will display a prominent red alarm icon and text prompt on the user interface, possibly accompanied by a buzzer sound; second, it will immediately stop the operation of all motion mechanisms and feeding mechanisms; finally, it will record this fault event along with all relevant data into non-volatile memory to form a historical fault log for subsequent analysis.

[0082] To address the extremely rare scenario where both the hardware comparator and the main processor fail simultaneously, a mechanical thermal fuse (thermal circuit breaker) can be connected in series in the power supply circuit of the heating module. This fuse is physically attached to the core heat-generating area of ​​the heating element. When the temperature exceeds its physical melting point, the fuse will permanently melt, cutting off the circuit at the most fundamental physical level.

[0083] During equipment operation, after the wire is drawn from the feed tray, it first enters the feeding mechanism, where the feeding amount is precisely controlled by the feeding gear driven by a stepper motor. The wire then enters the specially designed feeding tube heating zone. In conduction heating mode, heat is evenly conducted from the external heating element through the tube wall to the surface of the wire and gradually penetrates into the core of the wire. In convection heating mode, the controlled hot airflow forms a stable temperature field within the feeding tube, raising the overall temperature of the wire through convection heat transfer.

[0084] During this process, the moisture absorbed inside the wire gradually evaporates after being heated, and the resulting steam is discharged outside the equipment through the exhaust system along with the hot airflow, effectively avoiding bubbles and layer defects caused by moisture vaporization during printing.

[0085] The detection module monitors the wire temperature changes in real time using a high-precision temperature sensor, and the sensor data is transmitted to the temperature control module at millisecond-level frequency. The core processor of the temperature control module runs an advanced control algorithm, which not only performs PID adjustment based on the current temperature deviation, but also predicts the system status by analyzing temperature change trends and adjusts the heating power in advance.

[0086] For example, when an abnormal rate of temperature rise is detected, the system will anticipate the potential risk of overheating and proactively reduce the power; when the temperature response is slow, the power output will be appropriately increased to ensure that the filament remains in the optimal thermal state before entering the printhead melting unit.

[0087] During printing, the system achieves intelligent coordination between motion and temperature. When the print head needs to move rapidly, the temperature control module will gradually increase the heating power hundreds of milliseconds in advance to cope with the upcoming increase in extrusion volume; conversely, when the print head decelerates for fine printing, the system will reduce the power output accordingly to prevent the material from overheating and degrading.

[0088] This forward-looking temperature control strategy effectively solves the problem of extrusion instability caused by thermal inertia in traditional 3D printing, ensuring the molding quality in complex printing tasks.

[0089] The entire system achieves comprehensive visual control through dedicated monitoring software. The software interface displays the temperature curves, power output status, and system operating parameters of each heating zone in real time, while simultaneously recording complete process data. The system's built-in intelligent diagnostic function can analyze historical data to identify potential fault risks in advance, such as heating element aging and sensor drift, and remind users to perform preventative maintenance through an early warning mechanism. All operating data can be exported, providing a complete basis for process optimization and quality traceability.

[0090] This equipment achieves intelligent temperature management throughout the entire process, from feeding to molding. It solves the print quality problem caused by moisture content in the filament during multi-color printing by ensuring the material enters the melting stage in optimal condition through real-time preheating and precise temperature control. The dynamic temperature control strategy enables the equipment to adapt to various complex printing scenarios, maintaining stable extrusion quality whether for high-speed filling or fine contouring.

[0091] A complete monitoring and diagnostic system not only improves the reliability of the equipment, but also provides data support for process optimization, significantly improving printing success rate and finished product consistency.

[0092] This system exhibits broad material adaptability, perfectly handling a variety of thermoplastic materials such as PLA, ABS, nylon (PA), and polycarbonate (PC). For PLA, moderate preheating improves its flowability and reduces the risk of nozzle clogging; for ABS, precise temperature control effectively suppresses warping during printing; for highly hygroscopic materials like nylon, continuous heating and drying ensures full utilization of material properties; and for high-viscosity materials like polycarbonate, stable preheating significantly reduces extrusion resistance.

[0093] Compared to traditional drying silos, this solution offers significant advantages in energy efficiency. Traditional silos require continuous heating of the entire chamber's air, resulting in enormous energy consumption and low efficiency. This system, however, employs a precise, localized heating strategy, heating only the wire being used, significantly improving energy utilization. Furthermore, by achieving "on-demand heating," it avoids repeated heating of materials during storage, saving energy and preventing performance degradation caused by prolonged exposure to high temperatures.

[0094] This directional heating solution ensures effective preheating while achieving precise energy delivery and efficient utilization. It not only significantly reduces equipment operating costs, aligning with green manufacturing principles, but also ensures the material properties of the final product by avoiding excessive thermal history. For professional applications requiring long-term continuous printing, this energy efficiency advantage will generate significant economic and environmental benefits.

[0095] 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 real-time heating filament intelligent 3D printing device, comprising a filament feeding mechanism (1) and a printing mechanism (2), wherein the filament feeding mechanism (1) supplies external filament (200) to the printing mechanism (2) for 3D printing; characterized in that: It also includes a heating module (4) and a temperature control module (5) used in conjunction with the heating module (4); the heating module (4) is used to heat the external wire (200) output by the wire feeding mechanism (1), the printing mechanism (2) is used to perform 3D printing on the external wire (200) heated by the heating module (4), and the temperature control module (5) is used to regulate the heating temperature of the external wire (200) by the heating module (4).

2. The real-time filament heating intelligent 3D printing equipment according to claim 1, characterized in that: The real-time heating filament intelligent 3D printing equipment also includes a feed tube (3) for guiding the external filament (200) fed by the filament feeding mechanism (1) to the printing mechanism (2); a heating module (4) is used in conjunction with the feed tube (3); the heating module (4) is located upstream of the melting unit (21) of the printing mechanism (2) for heating the external filament (200) before it enters the melting unit (21).

3. The real-time filament heating intelligent 3D printing equipment according to claim 2, characterized in that: The heating module (4) is a conductive heating unit (41) and / or a convection heating unit (42). The conductive heating unit (41) includes a heating element disposed on the outside of the feed pipe (3). The heating element heats the wall of the feed pipe (3) to conduct heat to the external wire (200) inside the feed pipe (3).

4. The real-time filament heating intelligent 3D printing equipment according to claim 2, characterized in that: The heating element is a resistance heating coil (411) spirally wound around the outside of the feeding pipe (3), a liquid heating spiral coil, or a thick film electric heater attached to the outside of the feeding pipe (3).

5. The real-time filament heating intelligent 3D printing equipment according to claim 3, characterized in that: The convection heating unit (42) includes a hot air generator (421) for generating hot airflow and a three-way valve (422) connected to the feed pipe (3). The three-way valve (422) has a first port (423), a second port (424) and a third port (425) connected to each other. The first port (423) is connected to the input end of the feed pipe (3), the second port (424) is connected to the output end of the feed pipe (3), and the third port (425) is connected to the hot air output port of the hot air generator (421). The hot air generated by the hot air generator (421) is introduced into the feed pipe (3) through the third port (425) of the three-way valve (422) and undergoes convective heat exchange with the external wire (200) flowing through the feed pipe (3); the intelligent 3D printing equipment also includes an exhaust assembly set at the output end of the feed pipe (3), and the hot air after convective heat exchange is discharged through the exhaust assembly before entering the melting unit (21) of the printing mechanism (2).

6. The real-time filament heating intelligent 3D printing equipment according to claim 5, characterized in that: The hot air generator (421) includes a fan and a heater. The direction of the hot air flow is intersected with the direction of the external wire (200). The heater is located between the air outlet of the fan and the third port (425) of the three-way valve (422). The air flow generated by the fan is heated by the heater to form a hot air flow and is introduced into the feed pipe (3) through the third port (425).

7. The real-time filament heating intelligent 3D printing equipment according to claim 5, characterized in that: The exhaust assembly includes an exhaust pipe (431) communicating with the inner cavity of the feed pipe (3) and a heat dissipation unit disposed at the end of the exhaust pipe (431). The hot air flow introduced into the feed pipe (3) by the hot air generator (421) is discharged to the heat dissipation unit via the second interface (424) and the exhaust pipe (431) before reaching the melting unit (21) of the printing mechanism (2). The heat dissipation unit dissipates the hot air flow discharged from the exhaust pipe (431) to the outside of the intelligent 3D printing equipment.

8. The real-time heating intelligent 3D printing equipment for filaments according to claim 1, characterized in that: The temperature control module (5) is electrically connected to the main controller of the 3D printing equipment. The main controller is used to transmit motion trajectory planning data of the printing mechanism (2) to the temperature control module (5). The temperature control module (5) is configured to dynamically adjust the heating power of the heating module (4) according to the instantaneous motion speed of the print head (20) of the printing mechanism (2) in the motion trajectory data, so that the heating power is increased in advance when the print head (20) accelerates and the heating power is decreased in advance when the print head (20) decelerates.

9. The real-time heating intelligent 3D printing equipment for filaments according to claim 1, characterized in that: The feeding pipe (3) has a main body section (31) and a heat-conducting section (32). The heat-conducting section (32) includes an inner liner (321) made of high-temperature resistant polymer material and a heat-conducting layer (322) made of metal material. The heat-conducting layer (322) covers the outside of the inner liner (321). The heating module (4) is disposed outside the heat-conducting layer (322). The heating module (4) is provided with a heat-insulating sleeve (33) on its outside.

10. The real-time filament heating intelligent 3D printing equipment according to claim 1, characterized in that: The intelligent 3D printing equipment also includes a storage mechanism (7) and a switching mechanism (8) used in conjunction with the filament feeding mechanism (1). The storage mechanism (7) includes a bracket (71) and mounting positions (72) set on the bracket (71) for carrying external material trays (73). There are multiple mounting positions (72), and two adjacent mounting positions (72) are used to load external material trays (73) with different printing external filaments (200). The input end of the feeding tube (3) is connected to the switching mechanism (8). The switching mechanism (8) is used to connect the outlet of any mounting position (72) with the input end of the feeding tube (3) so that different printing external filaments (200) can be freely switched.

Images