3D printing nozzle with follow-up preheating function and thermal management control method thereof

Abstract

The application discloses a 3D printing nozzle with follow-up preheating function and a thermal management control method thereof, and belongs to the technical field of 3D printing technology. The mounting seat is arranged on the movable block in the walking mechanism, and the printer nozzle is arranged at the lower part of the mounting seat. The ceramic preheating strip is horizontally arranged at the lower part of the printer nozzle. The driving assembly is arranged on the mounting seat and comprises a driving mechanism connected with the ceramic preheating strip and a controller in communication connection with the main control system of the 3D printer, which is used for sending an angle instruction to the driving mechanism, so that the ceramic preheating strip always points to the front of the walking path of the printer nozzle during the printing movement of the printer nozzle. The ceramic preheating strip rotating synchronously with the nozzle realizes follow-up local precise preheating, significantly improves the interlayer bonding strength, and realizes the active thermal management of the interlayer interface with the advantages of precision, energy saving and safety through the angle closed-loop control and power linkage adjustment.

Description

Technical Field

[0001] This application relates to the field of 3D printing technology, specifically to a 3D printing nozzle with follow-up preheating function and its thermal management control method. Background Technology

[0002] Fused filament fabrication (FFF), as a widely used additive manufacturing technology, has advantages such as low equipment cost, simple operation, and efficient molding of complex geometric parts. It has shown great potential in the rapid manufacturing and small-batch production of polymer parts. Thermoplastic polymers such as polyetheretherketone (PEEK), polycarbonate (PC), and ABS all face the common problem of insufficient interlayer bonding strength during the FFF printing process.

[0003] During FFF printing, the high-temperature melt extruded from the printing nozzle is deposited layer by layer onto the surface of the cooled deposited layer. Since the temperature of the deposited layer is much lower than that of the newly extruded melt (the temperature difference can reach 150℃-200℃), a drastic temperature gradient is generated between the two, causing the melt to cool and solidify rapidly. During this process, the diffusion time and diffusion distance of polymer molecular chains at the interlayer interface are extremely short, making it difficult to form sufficient molecular chain entanglement and fusion, ultimately resulting in weak interfacial bonding. This problem severely restricts the mechanical properties of FFF printed parts, manifested as a high tendency for interlayer delamination, low overall strength, and significant anisotropy.

[0004] To improve the interlayer bonding quality of FFF printing, existing technologies mainly focus on the following two directions:

[0005] 1. Process parameter optimization: By increasing nozzle temperature, reducing printing speed, and reducing layer thickness, the cooling time of the melt can be extended to promote molecular chain diffusion. However, simply relying on parameter adjustment cannot fundamentally eliminate the temperature gradient at the interlayer interface, and excessively high temperatures can easily lead to thermal degradation of the material, limiting the potential for improving interlayer strength.

[0006] 2. Chamber heating and post-processing: Heating the printing chamber or performing post-processing such as annealing or hot isostatic pressing on the printed parts can slow down the cooling rate or eliminate internal defects. However, these methods are overall heating or post-compensation, which are energy-intensive and slow to respond, and cannot achieve local, precise, and real-time preheating of the area to be deposited.

[0007] Therefore, there is an urgent need to develop a 3D printing nozzle with follow-up preheating function that can overcome the above-mentioned shortcomings. Summary of the Invention

[0008] To overcome the shortcomings of the prior art, this invention discloses a 3D printing nozzle with follow-up preheating function and its thermal management control method. This invention achieves follow-up local precise preheating through a ceramic preheating strip that rotates synchronously with the nozzle, which significantly improves the interlayer bonding strength. Combined with angle closed-loop control and power linkage adjustment, it realizes precise, energy-saving and safe active thermal management of the interlayer interface.

[0009] To achieve the above objectives, this application provides the following technical solution:

[0010] A 3D printing nozzle with a follow-up preheating function, comprising a 3D printer consisting of a frame, a traveling mechanism and a printer nozzle, and further comprising:

[0011] The mounting base is located on the movable block inside the traveling mechanism, and the printer nozzle is located at the lower part of the mounting base;

[0012] A ceramic preheating strip is horizontally positioned at the bottom of the printer head. One end of the strip is rotatably connected to the nozzle of the printer head and can rotate around the nozzle of the printer head. It is used to preheat the printing layer below the printer head with thermal radiation.

[0013] The driver components, mounted on the mounting base, include:

[0014] The drive mechanism, connected to the ceramic preheating strip drive, is used to drive the ceramic preheating strip to rotate horizontally around the nozzle of the printer head.

[0015] The controller communicates with the main control system of the 3D printer and is used to send angle commands to the drive mechanism in real time according to the preset printing path in the main control system of the 3D printer, so that the ceramic preheating strip always points in front of the printer nozzle's travel path during the printing process.

[0016] Furthermore, the drive mechanism includes:

[0017] The servo motor is housed within the mounting bracket;

[0018] The drive rod is set parallel to the ceramic preheating strip, with one end connected to the output end of the servo motor.

[0019] The connecting rod has its two ends connected to the other end of the drive rod and the other end of the ceramic preheating strip, respectively, to achieve synchronous and co-rotation of the ceramic preheating strip and the drive rod.

[0020] Furthermore, the mounting base includes:

[0021] The mounting bracket is located on one side of the movable block within the walking mechanism;

[0022] The mounting rod, vertically positioned at the bottom of the mounting bracket, is used to connect the printer printhead.

[0023] Furthermore, the rotation range of the ceramic preheating bar is -180° to +180°, with the nozzle center axis as the 0° reference, and the servo motor achieves positioning through absolute position closed-loop control.

[0024] Furthermore, the horizontal projection of the vertical center axis of the mounting rod is located on the vertical line of the initial 0° position of the drive rod. When the drive rod rotates to ±180°, it contacts the mounting rod to accurately position and calibrate the rotation angle of the ceramic preheating strip.

[0025] Furthermore, both sides of the drive rod are provided with clearance notches that correspond to and fit the mounting rod.

[0026] Furthermore, the controller adopts a position closed-loop servo control mode, establishes real-time bus communication with the 3D printer's main control system, parses the 3D printer's printing path, and converts it into rotation angle commands for the servo motor.

[0027] Furthermore, the controller incorporates a timing control logic that prioritizes preheating and follows up with printing, driving the ceramic preheating strip to swing to the angle corresponding to the next trajectory before the printer nozzle completes printing the current trajectory.

[0028] Furthermore, the controller is also used to adjust the heating power of the ceramic preheating bar in conjunction with the angle positioning signal, increasing it to the rated power after the position is locked and reducing the power during the swing process.

[0029] A thermal management control method for a 3D printing nozzle with follow-up preheating function includes the following steps:

[0030] Step 1: Angle Command Conversion and Transmission: The 3D printer's main control system parses the printing path G-code generated by the slicing software to obtain the coordinates of the current printing segment's endpoint and the starting coordinates and direction angle of the next printing trajectory.

[0031] Step 2, Angle Command Conversion and Transmission: The controller converts the trajectory angle into a motor angular displacement command and sends it to the servo motor of the drive mechanism;

[0032] Step 3: Orientation and rotation of the ceramic preheating strip: The servo motor drives the ceramic preheating strip to rotate around the nozzle as the center, so that it always points in front of the printing path;

[0033] Step 4, Interface Preheating and Activation: The ceramic preheating strip preheats the area to be printed below with thermal radiation, raising the surface temperature of the deposited layer;

[0034] Step 5, Filament Deposition and Interface Bonding: The printer head moves along the path and extrudes the filament, achieving thermal-thermal interface bonding with the preheated deposited layer;

[0035] Step 6: Repeat Step 2 to Step 5 after completing the current trajectory to achieve layer-by-layer look-ahead warm-up and synchronous printing.

[0036] Compared with the prior art, the beneficial effects of this application are:

[0037] By setting a ceramic preheating strip that moves synchronously with the printer nozzle and is driven by the drive component to rotate in real time and always point in front of the travel path, the following local precise preheating of the area to be printed is realized. This solution transforms the traditional "hot-cold" interface between the high-temperature melt and the deposited layer into a "hot-hot" interface, actively regulating the thermal environment in the process of interlayer interface formation, and providing ideal thermodynamic conditions for the cross-layer diffusion and entanglement of polymer molecular chains.

[0038] By establishing real-time bus communication between the controller and the main control system of the 3D printer, the printing path G code is parsed and converted into angular displacement commands for the servo motor. Combined with absolute position closed-loop control, the ceramic preheating strip can be accurately positioned within the range of -180° to +180°. The servo driver collects encoder feedback signals in real time and dynamically adjusts the output torque and speed to ensure that the ceramic preheating strip is always accurately aligned with the area to be printed. The preheating pointing error is controlled within ±0.5°, effectively avoiding the technical problems of preheating deviation or lag, and achieving high-precision spatiotemporal synchronization between the preheating area and the printing area.

[0039] By incorporating a timing control logic of preheating first and printing follow-up into the controller, the ceramic preheating strip can be driven to swing to the corresponding angle of the next trajectory and preheat before the printer nozzle completes the current trajectory printing. After it is in place, the position is locked, thus realizing forward synchronous control of the preheating action and the printing motion.

[0040] By linking and adjusting the heating power with the angle positioning signal, the power is increased to the rated power after the position is locked, achieving rapid and efficient preheating. During the angle switching and swinging process, the power is adaptively reduced to avoid ineffective heating and excessive local temperature.

[0041] This invention achieves precise local preheating by using a ceramic preheating strip that rotates synchronously with the nozzle, significantly improving the interlayer bonding strength. Combined with angle closed-loop control and power linkage adjustment, it realizes precise, energy-saving, and safe active thermal management of the interlayer interface. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the structure of the present invention;

[0043] Figure 2 This is a schematic diagram of the drive component structure of the present invention;

[0044] In the diagram: 1. Frame; 2. Traveling mechanism; 3. Mounting base; 3.1. Mounting bracket; 3.2. Mounting rod; 4. Printer nozzle; 4.1. Extruder; 4.2. Nozzle; 5. Ceramic preheating strip; 6. Drive assembly; 6.1. Drive mechanism; 6.1.1. Servo motor; 6.1.2. Drive rod; 6.1.2.1. Notch; 6.1.3. Connecting rod; 6.2. Controller. Detailed Implementation

[0045] The technical solution of the present invention will be described below with reference to the accompanying drawings of the embodiments of the present invention. In the description, it should be understood that if there are terms such as "upper", "lower", "front", "rear", "left", "right" indicating the orientation or positional relationship, they are only corresponding to the accompanying drawings of the present invention for the convenience of describing the present invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation.

[0046] Please refer to the instruction manual appendix. Figure 1-2 The present invention provides a technical solution:

[0047] This embodiment provides a 3D printing nozzle with a follow-up preheating function, including a 3D printer consisting of a frame 1, a traveling mechanism 2 and a printer nozzle 4, and also includes a mounting base 3, a ceramic preheating strip 5 and a drive assembly 6. The mounting base 3 is disposed on a movable block inside the traveling mechanism 2, and the printer nozzle 4 is disposed at the lower part of the mounting base 3. Specifically, the mounting base 3 includes a mounting frame 3.1 and a mounting rod 3.2. The mounting frame 3.1 is fixedly disposed on one side of the movable block inside the traveling mechanism 2, and the mounting rod 3.2 is vertically disposed at the lower part of the mounting frame 3.1, and its lower end is fixedly connected to the extruder 4.1 inside the printer nozzle 4.

[0048] The ceramic preheating strip 5 is horizontally positioned below the printer nozzle 4. One end of the strip is rotatably connected to the nozzle 4.2 of the printer nozzle 4 and can rotate horizontally around the nozzle of the printer nozzle 4. The ceramic preheating strip 5 is made of high-temperature alumina ceramic material. The ceramic preheating strip 5 integrates a nickel-chromium alloy or tungsten resistance wire (embedded internal heating wire). When current passes through the resistance wire, electrical energy is converted into heat energy, which raises the temperature of the ceramic preheating strip 5 body. This heat energy is used to preheat the printing layer below the printer nozzle 4 by radiation, raising the surface temperature of the deposited layer to above the glass transition temperature of the printing material.

[0049] The drive assembly 6 is mounted on the mounting base 3 and includes a drive mechanism 6.1 and a controller 6.2. The drive mechanism 6.1 is driven and connected to the ceramic preheating strip 5 and is used to drive the ceramic preheating strip 5 to rotate horizontally around the nozzle of the printer nozzle 4. The controller 6.2 is communicatively connected to the main control system of the 3D printer and is used to send angle commands to the drive mechanism 6.1 in real time according to the preset printing path in the main control system of the 3D printer, so that the ceramic preheating strip 5 always points in front of the printer nozzle 4's travel path during the printing movement of the printer nozzle 4.

[0050] Specifically, the drive mechanism 6.1 includes a servo motor 6.1.1, a drive rod 6.1.2, and a connecting rod 6.1.3. The servo motor 6.1.1 is fixedly installed inside the mounting bracket 3.1, with its output shaft extending vertically downwards. The drive rod 6.1.2 is arranged vertically parallel to the ceramic preheating strip 5. One end of the drive rod 6.1.2 is fixedly connected to the output end of the servo motor 6.1.1 and can rotate synchronously with the output shaft of the servo motor 6.1.1. The two ends of the connecting rod 6.1.3 are rotatably connected to the other ends of the drive rod 6.1.2 and the ceramic preheating strip 5, respectively, to achieve synchronous and co-directional rotation of the ceramic preheating strip 5 and the drive rod 6.1.2. When the servo motor 6.1.1 drives the drive rod 6.1.2 to rotate, the ceramic preheating strip 5 rotates synchronously with the nozzle 4.2 at the same angle through the transmission action of the connecting rod 6.1.3, thereby ensuring that the direction of the ceramic preheating strip 5 is always consistent with the direction of the drive rod 6.1.2.

[0051] In this embodiment, the working process of the printer printhead 4 is as follows:

[0052] Before printing begins, controller 6.2 establishes real-time bus communication with the 3D printer's main control system to obtain the printing path G-code generated by the slicing software. Controller 6.2 parses the G-code and extracts the direction angle of the current printing segment as well as the starting coordinates and direction of the next printing trajectory.

[0053] When the printer head 4 starts moving along the preset path, the controller 6.2 calculates the angle that the ceramic preheating strip 5 should point to in real time according to the direction of the current printing path, and converts the angle into an angular displacement command for the servo motor 6.1.1 and sends it to the servo driver. The servo driver drives the servo motor 6.1.1 to rotate, which drives the ceramic preheating strip 5 to rotate synchronously through the drive rod 6.1.2 and the connecting rod 6.1.3, so that the ceramic preheating strip 5 always points in front of the printer head 4's travel path;

[0054] During rotation, the ceramic preheating strip 5 continuously preheats the area to be printed below with thermal radiation. When the printer nozzle 4 moves to this area, the newly extruded high-temperature molten wire is deposited on the surface of the preheated deposited layer. Since the surface temperature of the deposited layer has been raised to near or above the glass transition temperature of the material, the temperature gradient between the new melt and the deposited layer is greatly reduced, and the cooling rate of the two is slowed down. This provides sufficient time and thermodynamic conditions for the cross-interfacial diffusion and entanglement of polymer molecular chains, thereby forming a strong interlayer bond.

[0055] After completing the printing of the current trajectory, controller 6.2 continues to analyze the direction of the next trajectory segment, repeating the above angle calculation and driving process to achieve layer-by-layer and segment-by-segment look-ahead warm-up and synchronous printing.

[0056] As another optional embodiment of the present invention, the rotation range of the ceramic preheating strip 5 is -180° to +180°, with the central axis of the nozzle of the printer head 4 as the 0° reference position. The servo motor 6.1.1 adopts an absolute position closed-loop control mode, and the absolute angular position of the motor rotor is fed back in real time through the built-in absolute encoder to achieve precise positioning of the rotation angle of the ceramic preheating strip 5.

[0057] The controller 6.2 adopts a position closed-loop servo control mode and establishes real-time bus communication with the main control system of the 3D printer (such as RS485, CAN bus or EtherCAT). It exchanges data in real time at a communication frequency of not less than 100Hz. The controller 6.2 parses the printing path G code sent by the main control system of the 3D printer, extracts the starting coordinates, ending coordinates and direction angle of each printing line segment, and converts the angle data into angular displacement commands for the servo motor 6.1.1.

[0058] During the printing process, the servo driver collects the angle signal fed back by the encoder of the servo motor 6.1.1 in real time, compares the commanded angle with the actual angle, and when there is a deviation between the two, the servo driver dynamically adjusts the output torque and speed to make the actual angle quickly converge to the commanded angle, ensuring that the pointing accuracy of the ceramic preheating strip 5 is controlled within ±0.5°.

[0059] Specifically, when the printer head 4 moves along the positive X-axis, the controller 6.2 calculates that the current path direction angle is 0°, and then sends a command to the servo motor 6.1.1 to drive the ceramic preheating strip 5 to rotate to the 0° position. That is, the length direction of the ceramic preheating strip 5 is consistent with the movement direction of the printer head 4, and the ceramic preheating strip 5 is located behind the printer head 4 (relative to the movement direction). When the printer head 4 turns to the next path segment (such as when the direction angle changes to 90°), the controller 6.2 sends a new angle command in advance, and the servo motor 6.1.1 drives the ceramic preheating strip 5 to swing quickly to the 90° position, ensuring that the ceramic preheating strip 5 has completed the pointing adjustment before the printer head 4 reaches the turning point.

[0060] The timing control logic for ceramic preheating bar 5 is as follows:

[0061] 0.2-0.5 seconds before the printer nozzle 4 completes printing the current trajectory, the controller 6.2 sends the angle command corresponding to the next trajectory in advance according to the preset path;

[0062] Servo motor 6.1.1 drives ceramic preheating bar 5 to swing to the target angle at an angular velocity of not less than 200° / s;

[0063] After the ceramic preheating strip 5 is in place, the servo motor 6.1.1 maintains the position locked state and outputs holding torque to prevent the ceramic preheating strip 5 from deviating from the target direction due to external force vibration;

[0064] After the printer nozzle 4 moves to the trajectory and completes the extrusion printing, the controller 6.2 sends the angle command for the subsequent trajectory again, and repeats the above look-ahead warm-up action.

[0065] Through the above-mentioned absolute position closed-loop control, the ceramic preheating strip 5 can always maintain a leading pointing direction during the movement of the printer nozzle 4, achieving precise following preheating of the area to be printed.

[0066] In this embodiment, the horizontal projection of the vertical center axis of the mounting rod 3.2 is located on the perpendicular bisector of the initial 0° position of the drive rod 6.1.2. Specifically, when the drive rod 6.1.2 is in the initial 0° position, its length direction line (i.e., the line connecting the output shaft center of the servo motor 6.1.1 to the connection point of the connecting rod 6.1.3) is perpendicular to the radial direction of the mounting rod 3.2 (i.e., the direction of the shortest distance from the center of the mounting rod 3.2 to the drive rod 6.1.2), and a safety gap of 0.5-1.5mm is left between the drive rod 6.1.2 and the mounting rod 3.2, so that the two do not contact each other.

[0067] When the servo motor 6.1.1 drives the drive rod 6.1.2 to rotate +180° in the forward direction or -180° in the reverse direction to reach its limit position, the side wall surface of the drive rod 6.1.2 just forms an abutment fit with the outer wall surface of the mounting rod 3.2. The function of this abutment fit is as follows:

[0068] Provides a physical limit reference: The contact position serves as the physical endpoint of the rotation of the drive rod 6.1.2, providing a precise and repeatable mechanical reference point for the absolute position closed-loop control of the servo motor 6.1.1. When the servo motor 6.1.1 performs zero-point calibration or angle reset, the controller 6.2 controls the drive rod 6.1.2 to rotate to the position of contacting the mounting rod 3.2, and records the encoder reading at this position as a ±180° limit reference, thereby ensuring the angular positioning accuracy of the ceramic preheating strip 5 throughout the entire rotation range;

[0069] Preventing overtravel rotation: The abutment mechanism prevents the drive rod 6.1.2 from continuing to rotate beyond the ±180° range, avoiding overtravel caused by abnormal control or motor step loss, and protecting the ceramic preheating strip 5 and its connecting parts from colliding with the surrounding structure.

[0070] Zero-point calibration: When the system is powered on or an abnormal position occurs, the controller 6.2 can control the servo motor 6.1.1 to drive the drive rod 6.1.2 to rotate slowly until it touches the mounting rod 3.2. The zero point is recalibrated based on this position to ensure the accuracy of subsequent angle control.

[0071] In this embodiment, both sides of the drive rod 6.1.2 are provided with clearance notches 6.1.2.1 that correspond to and are adapted to the mounting rod 3.2. When the drive rod 6.1.2 rotates to an angle position close to the mounting rod 3.2 (such as the range of ±170° to ±180°), the clearance notches 6.1.2.1 provide partial clearance space for the mounting rod 3.2, preventing the body of the drive rod 6.1.2 from prematurely contacting or interfering with the mounting rod 3.2, and ensuring that only at the ±180° extreme position, a specific part of the drive rod 6.1.2 (the edge of the notch or the side wall) comes into contact with the mounting rod 3.2.

[0072] When the ceramic preheating strip 5 needs to be preheated at the +180° position, the controller 6.2 sends a +180° angular displacement command to the servo motor 6.1.1. The servo motor 6.1.1 drives the drive rod 6.1.2 to rotate forward. When the drive rod 6.1.2 rotates to near +180°, it avoids the notch 6.1.2.1 and bypasses the mounting rod 3.2. Finally, the side wall of the drive rod 6.1.2 forms a stable contact with the outer wall of the mounting rod 3.2. The servo driver detects the position arrival signal (or detects a slight increase in current / torque), confirms that the limit position has been reached, and then maintains the position lock state. The ceramic preheating strip 5 performs preheating operations in the +180° direction. When it is necessary to switch to other angles, the servo motor 6.1.1 rotates in the reverse direction, and the drive rod 6.1.2 smoothly disengages from the contact state and rotates to the new target angle.

[0073] In this embodiment, the controller 6.2 analyzes the continuous trajectory in the printing path G code and uses Kalman filtering or cubic spline interpolation algorithms to predict the directional change trend of the next 2-5 printing segments (approximately 5-20mm printing length). When an acute-angle turn (turning angle ≥90°) or a continuous small line segment forming a curved path is detected in the printing path, the controller 6.2 drives the ceramic preheating strip 5 to start swinging in the direction of the turned path 0.2-0.5 seconds before the printer nozzle 4 reaches the turning point. This allows the change in the direction of the ceramic preheating strip 5 to respond synchronously with the change in the moving trajectory of the printer nozzle 4, eliminating the preheating lag caused by the sudden change in path direction.

[0074] Specifically, when a 120° path turn is detected in the printing path, the controller 6.2 calculates the angle difference before and after the turn and generates a smooth angle change curve (instead of a step angle command). The servo motor 6.1.1 continuously changes its angle according to the curve, so that the ceramic preheating strip 5 always stays ahead as the printer nozzle 4 passes through the turning point, avoiding the offset of the heating area caused by the sudden change in angle.

[0075] As another optional embodiment of the present invention, the timing control logic and heating power linkage control of the controller 6.2 are defined in detail. Specifically, the controller 6.2 has built-in timing control logic of preheating first and printing follow-up, which specifically includes the following stages:

[0076] Prediction phase: Controller 6.2 caches the path data of the next 3-5 printing segments in real time. By analyzing the continuous trajectory in the path G code, it predicts the future trend of printing direction changes in advance. When a sudden change in direction (turning angle ≥ 45°) is detected in the path, controller 6.2 marks the sudden change point as a key node that needs to be responded to in advance.

[0077] Preheating phase: Before the printer nozzle 4 completes the current trajectory printing, the controller 6.2 drives the servo motor 6.1.1 0.2-1.0 seconds in advance according to the predicted direction of the next trajectory, so that the ceramic preheating strip 5 swings quickly to the angle corresponding to the next trajectory. During this phase, the ceramic preheating strip 5 begins to preheat the target area.

[0078] Position locking stage: After the ceramic preheating strip 5 reaches the target angle, the servo motor 6.1.1 switches to the position locking mode and outputs holding torque (30%-50% of the rated torque) to maintain the angle stability and ensure that the heating area is pointed accurately. During this stage, the ceramic preheating strip 5 maintains full power heating to continuously preheat the area to be printed to the set temperature.

[0079] Printing stage: The printer nozzle 4 moves along the preset path to the area, and the newly extruded high-temperature molten wire is deposited on the surface of the preheated deposited layer, completing a high-quality interlayer bonding;

[0080] Cyclic Phase: After the printer nozzle 4 completes the printing of the current trajectory, the controller 6.2 re-analyzes the subsequent trajectory and repeats the above-mentioned look-ahead warm-up and angle switching actions to achieve layer-by-layer and segment-by-segment look-ahead warm-up and synchronous printing.

[0081] The controller 6.2 is also used to adjust the heating power of the ceramic preheating bar (5) in conjunction with the angle positioning signal. After the position is locked, the power is increased to the rated power, and the power is reduced during the swing process. The specific control strategy is as follows:

[0082] Preheating and locking stage: After the ceramic preheating strip 5 swings to the target angle and completes the position locking, the controller 6.2 outputs a full power drive signal to increase the heating power of the ceramic preheating strip 5 to the rated power (such as 100W-200W), so as to quickly preheat the area to be printed below with the maximum heat radiation intensity, and raise the surface temperature of the deposited layer to the target preheating temperature within 1-2 seconds.

[0083] Angle switching swing stage: When the controller 6.2 sends a new angle command and the ceramic preheating strip 5 starts to swing, the controller 6.2 automatically reduces the heating power to the maintenance power (15%-30% of the rated power), only maintaining the basic temperature of the ceramic preheating strip 5 (such as 150℃-200℃), avoiding ineffective heating of non-target areas during the swing process, and preventing local overheating due to long-term static heating;

[0084] Standby and idle phase: When the printer printhead 4 is not printing (such as changing materials, returning to the origin, or waiting for instructions), the controller 6.2 further reduces the heating power to the standby power (5%-10% of the rated power) and enters the low-temperature standby mode, which ensures that the preheating demand can be responded to quickly, while also achieving energy saving and extending the life of the heating element.

[0085] In this embodiment, in order to realize the temperature control of the ceramic preheating strip 5 by the controller 6.2, the controller 6.2 integrates a PID adjustment module and is connected to a K-type thermocouple (fixed to the surface of the ceramic preheating strip 5) to form a closed-loop temperature control system. The PID adjustment module dynamically adjusts the output power of the ceramic preheating strip 5 at an adjustment frequency of 10-50Hz to stabilize the preheating temperature within ±3℃ of the set value.

[0086] When printing PEEK (polyetheretherketone) material, considering both material properties and printing efficiency, the preheating temperature of the ceramic preheating strip 5 can be set to multiple gradients such as 240℃, 260℃, 280℃, or 300℃. Experimental verification shows that when the preheating temperature is 280℃, the surface temperature of the deposited layer can be maintained at 200-220℃, and the tensile strength of the printed part can reach 69.47MPa, which is 21.3% higher than that without preheating (57.27MPa), the elongation at break is increased by 18.2%, and the porosity is reduced from 12.05% to 8.36%, resulting in the best overall performance.

[0087] As an operating method of a 3D printer nozzle according to the present invention, the method includes the following steps:

[0088] Step 1: Path analysis and angle prediction;

[0089] The 3D printer's main control system parses the G-code of the printing path generated by the slicing software, extracting the coordinates of the end point of the current printing segment and the starting coordinates and direction angle of the next printing trajectory. Controller 6.2 acquires the above data through real-time bus communication and uses linear interpolation or spline fitting algorithms to predict the directional change trend of the continuous printing trajectory.

[0090] Step 2: Angle command conversion and transmission;

[0091] The controller 6.2 converts the trajectory angle obtained in step one into an angular displacement command for the servo motor 6.1.1, and sends it to the servo driver in absolute value form. The command includes the target angle value (range -180° to +180°), rotation speed (adjustable range 100° / s-300° / s), and acceleration parameters.

[0092] Step 3: Orient the ceramic preheating bar;

[0093] After receiving the command, the servo driver drives the servo motor 6.1.1 to rotate according to the set speed and acceleration curve. The servo motor 6.1.1 drives the ceramic preheating strip 5 to rotate synchronously around the nozzle as the center through the drive rod 6.1.2 and the connecting rod 6.1.3, so that the length direction of the ceramic preheating strip 5 always points to the front of the printing path (that is, the ceramic preheating strip 5 is located behind the printer nozzle 4 in the direction of movement, and its radiation area covers the area to be printed).

[0094] During this process, the servo motor 6.1.1 adopts absolute position closed-loop control, collects encoder feedback signals in real time, compares the command angle with the actual angle, and dynamically adjusts the output torque and speed to control the angle following error within ±0.5°.

[0095] Step 4: Interface preheating and activation;

[0096] The ceramic preheating strip 5 preheats the area to be printed below with thermal radiation. According to the Stefan-Boltzmann thermal radiation law, the ceramic preheating strip 5 transfers thermal radiation energy to the surface of the deposited layer, raising its surface temperature to above the glass transition temperature (143°C) of the printing material (such as PEEK).

[0097] When the surface temperature of the deposited layer exceeds the glass transition temperature, the material surface changes from a glassy state to a highly elastic state, which activates the mobility of the surface molecular chains, transforming the material from its original hard and brittle state to a soft state with viscoelasticity, thus providing favorable conditions for the interface fusion during the subsequent deposition of new melt.

[0098] Step 5: Fused wire deposition and interface bonding;

[0099] The printer nozzle 4 moves along a preset path, and the nozzle extrudes a high-temperature molten wire (such as PEEK melt with a temperature of 400°C) and deposits it onto the surface of the preheated and activated deposited layer. At this time, both the newly extruded high-temperature melt and the preheated deposited layer are at a high temperature level, and the original "hot-cold" contact mode is transformed into a "hot-hot" contact mode.

[0100] Under reduced temperature gradient and slowed cooling rate, polymer molecular chains on both sides of the interface have high mobility, which can fully diffuse and entangle across the interface to form a strong interlayer bond, rather than a simple mechanical anchoring.

[0101] Step 6: Repeat the process.

[0102] After completing the printing of the current trajectory, controller 6.2 returns to step one, obtains subsequent trajectory data, and repeats steps two to five to achieve layer-by-layer look-ahead preheating and synchronous printing until the entire part is printed.

[0103] During the above operation, the encoder of the servo motor 6.1.1 monitors the rotation position in real time. When the deviation between the encoder feedback position and the command angle exceeds the set tolerance threshold (such as ±2°), the controller 6.2 determines that it is out of step and automatically triggers the reset program: controls the servo motor 6.1.1 to drive the drive rod 6.1.2 to rotate slowly until it touches the 0° reference position of the mounting rod 3.2, and then recalibrates the zero point and continues the printing task.

[0104] Meanwhile, the controller 6.2 has built-in hardware and software dual angle limit protection. When the parsed command angle exceeds the ±180° setting range, the servo driver automatically blocks the invalid command and sends an over-limit alarm signal to the main control system to limit the maximum swing angle of the motor and prevent mechanical interference and mechanical damage.

[0105] The parts of this invention not described in detail are prior art. It will be apparent to those skilled in the art that this invention is not limited to the details of the above exemplary embodiments, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the above embodiments should be regarded as exemplary and non-limiting in all respects. The scope of this invention is defined by the appended claims rather than the foregoing description. Therefore, it is intended to include all changes falling within the meaning and scope of the equivalents of the claims within this invention, and no reference numerals in the claims should be regarded as limiting the content of the claims.

Claims

1. A 3D printing nozzle with a follow-up preheating function, comprising a 3D printer consisting of a frame (1), a traveling mechanism (2), and a printer nozzle (4), characterized in that, Also includes: Mounting base (3) is set on the movable block inside the walking mechanism (2), and printer nozzle (4) is set at the lower part of mounting base (3); A ceramic preheating strip (5) is horizontally positioned at the bottom of the printer nozzle (4). One end of the strip is rotatably connected to the nozzle (4.2) of the printer nozzle (4) and can rotate around the nozzle (4.2) of the printer nozzle (4) as the center. It is used to preheat the printing layer below the printer nozzle (4) with thermal radiation. The drive component (6), mounted on the mounting base (3), includes: The drive mechanism (6.1) is connected to the ceramic preheating strip (5) and is used to drive the ceramic preheating strip (5) to rotate horizontally with the nozzle (4.2) of the printer nozzle (4) as the center. The controller (6.2) is connected to the main control system of the 3D printer and is used to send angle commands to the drive mechanism (6.1) in real time according to the preset printing path in the main control system of the 3D printer, so that the ceramic preheating strip (5) always points in front of the printing nozzle (4) during the printing movement of the printer nozzle (4).

2. A 3D printing nozzle with follow-up preheating function according to claim 1, characterized in that: The drive mechanism (6.1) includes: The servo motor (6.1.1) is housed within the mounting bracket (3.1); The drive rod (6.1.2) is set vertically and parallel to the ceramic preheating strip (5), and one end of it is connected to the output end of the servo motor; The connecting rod (6.1.3) is connected at both ends to the other end of the drive rod (6.1.2) and the other end of the ceramic preheating strip (5) respectively, so as to realize the synchronous rotation of the ceramic preheating strip (5) and the drive rod (6.1.2) in the same direction.

3. A 3D printing nozzle with follow-up preheating function according to claim 2, characterized in that: Mounting base (3) includes: Mounting bracket (3.1) is installed on one side of the movable block inside the walking mechanism (2); The mounting rod (3.2) is vertically positioned at the bottom of the mounting bracket (3.1) and is used to connect the printer nozzle (4).

4. A 3D printing nozzle with follow-up preheating function according to claim 3, characterized in that: The rotation range of the ceramic preheating strip (5) is -180° to +180°, with the nozzle center axis as the 0° reference. The servo motor (6.1.1) achieves positioning through absolute position closed-loop control.

5. A 3D printing nozzle with follow-up preheating function according to claim 4, characterized in that: The horizontal projection of the vertical center axis of the mounting rod (3.2) is located on the vertical line of the initial 0° position of the drive rod (6.1.2). When the drive rod (6.1.2) rotates to ±180°, it contacts the mounting rod (3.2) to accurately position and zero-point calibrate the rotation angle of the ceramic preheating strip (5).

6. A 3D printing nozzle with follow-up preheating function according to claim 5, characterized in that: Both sides of the drive rod (6.1.2) are provided with clearance notches (6.1.2.1) that correspond to and fit the mounting rod (3.2).

7. A 3D printing nozzle with follow-up preheating function and its thermal management control method according to claim 2, characterized in that: The controller (6.2) adopts a position closed-loop servo control mode, establishes real-time bus communication with the main control system of the 3D printer, parses the printing path of the 3D printer and converts it into the rotation angle shift command of the servo motor (6.1.1).

8. A 3D printing nozzle with follow-up preheating function according to claim 1, characterized in that: The controller (6.2) has built-in timing control logic of preheating first and printing follow-up, which drives the ceramic preheating strip (5) to swing to the corresponding angle of the next trajectory before the printer nozzle (4) completes the printing of the current trajectory.

9. A 3D printing nozzle with follow-up preheating function according to claim 1, characterized in that: The controller (6.2) is also used to adjust the heating power of the ceramic preheating bar (5) in conjunction with the angle positioning signal, increase the power to the rated power after the position is locked, and reduce the power during the swing process.

10. A thermal management control method for a 3D printing nozzle with follow-up preheating function according to any one of claims 1-9, characterized in that: It also includes the following steps: Step 1: Angle Command Conversion and Transmission: The 3D printer's main control system parses the printing path G-code generated by the slicing software to obtain the coordinates of the current printing segment's endpoint and the starting coordinates and direction angle of the next printing trajectory. Step 2, Angle command conversion and transmission: The controller (6.2) converts the trajectory angle into a motor angular displacement command and sends it to the servo motor (6.1.1) of the drive mechanism (6). Step 3, Orientation and Rotation of Ceramic Preheating Strip: The servo motor (6.1.1) drives the ceramic preheating strip (5) to rotate around the nozzle, so that it always points in front of the printing path; Step 4, Interface preheating and activation: The ceramic preheating strip (5) preheats the area to be printed below with thermal radiation to increase the surface temperature of the deposited layer; Step 5, Wire Deposition and Interface Bonding: The printer nozzle (4) moves along the path and extrudes the wire, achieving a thermal-thermal interface bonding with the preheated deposited layer; Step 6: Repeat Step 2 to Step 5 after completing the current trajectory to achieve layer-by-layer look-ahead warm-up and synchronous printing.

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