Four-axis coplanar high-precision control photocuring 3D printer and control method thereof

Abstract

The invention discloses a four-axis coplanar high-precision control photocuring 3D printer and a control method thereof.The four-axis coplanar high-precision control photocuring 3D printer comprises a photocuring 3D printer body, the photocuring 3D printer body comprises a base, and a display screen is embedded in the top of the base; the sinking groove is formed in the top of the base, and the sinking groove is formed over the display screen; the top frame is arranged above the base; and a lifting platform. The Z-axis lifting mechanisms with the four axes arranged in the same plane are adopted, the direct-current motor with the high response speed, the precise transmission lead screw and the positioning rod structure are arranged, the Z-axis + / -0.01 mm level positioning precision is achieved, the four Z-axis lifting mechanisms are symmetrically distributed in a regular matrix mode, mechanical deformation is reduced by combining the four Z-axis lifting mechanisms with the rigid frame, and the space utilization rate is optimized; the diagonal motors adopt symmetrical steering design, torque distribution is adjusted through speed regulation, the overturning risk of the machine body is effectively reduced, and the printing stability is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing, and in particular to a four-axis co-planar high-precision controlled light-curing 3D printer and a control method thereof. Background Art

[0002] Currently, stereolithography (SLA) 3D printing technology is widely used in the manufacturing industry, particularly in the production of elastomeric parts such as shoe molds. Traditional SLA 3D printers typically employ a single-axis drive or three-axis linkage design, stacking layers by controlling the up-and-down motion of the Z-axis. During the printing process, the print platform descends layer by layer, and a light projection system projects each layer's pattern onto the photosensitive resin material based on the slice data. After the material solidifies, it accumulates layer by layer to form the final product. This method has been widely used in the manufacturing of small parts or products with simple structures.

[0003] However, existing technologies present numerous drawbacks when printing large-scale elastomer products. First, elastomer materials like TPU shrink significantly during the curing process (variations can reach 0.5%-2%). This, combined with the release forces of multiple layers, leads to stress concentrations at the corners of the molding platform, causing edge warping and interlayer delamination. Second, traditional single-axis drive systems are prone to Z-axis positioning deviations (errors >0.1mm) due to mechanical backlash or step loss, exacerbating platform tilt and increasing the risk of pressure cracking of the underlying glass. Third, existing technologies lack a real-time monitoring mechanism for the pressure distribution on the printing platform, making it impossible to dynamically adjust motor operating parameters. This can lead to localized pressure overloads and deformation of the printing platform. Furthermore, material options are limited. Commonly used materials such as TPU and TPE lack properties such as breathability and elasticity, making them inadequate for the wear resistance and lightweight requirements of high-end shoe molds. Furthermore, issues such as slow printing speeds, high overall costs, unstable process accuracy, difficulty in achieving complex structures, and cumbersome material tray replacements have hindered the application of stereolithography 3D printing technology in the mass production of large-scale elastomers.

[0004] Therefore, there is an urgent need for a four-axis co-planar high-precision controlled light-curing 3D printer and its control method that can effectively solve the above problems. The equipment should have a high-precision Z-axis control system, the function of real-time monitoring of the pressure distribution of the printing platform, advanced material processing technology and optimized printing process to meet the mass production needs of large-size elastomer parts, especially shoe molds and other products, and improve printing accuracy, efficiency and finished product quality. Summary of the Invention

[0005] The purpose of the present invention is to provide a four-axis coplanar high-precision controlled light-curing 3D printer and a control method thereof, so as to solve the problems existing in the existing light-curing 3D printing technology mentioned in the above background technology.

[0006] To achieve the above-mentioned object, the present invention provides the following technical solution: a four-axis coplanar high-precision controlled light-curing 3D printer, comprising a light-curing 3D printer body, wherein the light-curing 3D printer body comprises: A base, wherein a display screen is embedded in the top of the base; A sinking trough is installed on the top of the base, and the sinking trough is arranged directly above the display screen; A top frame, arranged above the base; A lifting platform is movably arranged between the top frame and the base, wherein a plurality of groups of suspension rods are fixedly connected to the bottom of the lifting platform, and a plurality of groups of suspension rods are fixedly connected to the bottom of the printing platform; Four groups of Z-axis lifting mechanisms are arranged in a regular matrix on the base, the lifting platform and the top frame, and the Z-axis lifting mechanism is suitable for controlling the lifting of the lifting platform.

[0007] Preferably, the top of the printing platform is a quadrangular pyramid structure.

[0008] Preferably, the Z-axis lifting mechanism includes: A driving motor is installed on the top of the top frame; An internal threaded sleeve, fixedly inserted into the lifting platform; A fixed base, fixed to the top of the base by bolts; a bottom bearing fixed in the top of the fixed base; A transmission screw rod is connected to the inner side of the internal threaded sleeve through a threaded structure, the top of the transmission screw rod is fixedly connected to the motor shaft of the drive motor, and the bottom of the transmission screw rod is fixed to the inner ring of the bottom bearing; A positioning sleeve, fixedly inserted into the lifting platform; A positioning rod, fixed between the bottom of the top frame and the top of the base; Wherein, the positioning rod is loosely fitted into the positioning sleeve, and the positioning rod is arranged parallel to the transmission screw.

[0009] Preferably, the Z-axis lifting mechanism further includes: Two sets of upper protection boxes are fixed to the top of the lifting platform by bolts; a lower protective box, fixed to the top of the base by bolts; The two groups of upper protective boxes are spliced ​​in half to form a box structure cover which is arranged on the outer side of the upper end of the internal threaded sleeve and the positioning sleeve, and the lower protective box cover is arranged on the outer side of the fixed base.

[0010] Preferably, the Z-axis lifting mechanism further includes a mechanical sensor, which is arranged at the connection between the printing platform and the suspension rod, and the mechanical sensor is suitable for monitoring the pressure distribution at the four corners of the printing platform in real time.

[0011] A control method for a four-axis coplanar high-precision controlled light-curing 3D printer is applied to the four-axis coplanar high-precision controlled light-curing 3D printer, comprising the following steps: S1) receiving printing task instructions, parsing 3D model files, and generating layered slice data; S2) Initializing the Z-axis position, and adjusting the printing platform to an initial height through the four sets of Z-axis lifting mechanisms; S3) Turn on the light source projection system and project each layer of pattern onto the photosensitive resin material in the tray according to the slice data; S4) monitoring the pressure distribution at the four corners of the printing platform in real time using a mechanical sensor; S5) dynamically adjusting the motor drive parameters of the four Z-axis lifting mechanisms using a torque balancing algorithm based on feedback data from the mechanical sensors to achieve balanced lifting of the printing platform; S6) After the curing of the current layer is completed, the four Z-axis lifting mechanisms are controlled to synchronously lift the printing platform to the next layer printing height, and steps S3 to S5 are repeated until the entire printing task is completed; The position of each motor is monitored by an encoder or a grating ruler, and the controller adjusts the output pulse to reduce the cumulative error. The torque balancing algorithm balances the load of each motor and reduces the eccentric load caused by the difference in mechanical structure.

[0012] Preferably, in step S2, the method for initializing the Z-axis position includes: S2.1) Controlling the four Z-axis lifting mechanisms to slowly lower the printing platform; S2.2) detecting, using a mechanical sensor, a change in pressure when the printing platform contacts the material tray; S2.3) When the pressure exceeds the preset threshold, the machine stops descending and records the current Z-axis coordinate as the printing starting point; Among them, synchronization instructions are sent to the motor driver board through the RS485 protocol, and the timer is combined to coordinate the timing of the four motor actions, and it has the functions of abnormal detection and instruction retransmission.

[0013] Preferably, in step S5, the torque balancing algorithm specifically includes: S5.1) Calculating the pressure difference at the four corners of the printing platform; S5.2) Calculating compensation amounts for the motors corresponding to the four Z-axis lifting mechanisms based on the pressure differences; S5.3) Sending compensation parameters to the motor driver board to adjust the speed and position of each motor to keep the printing platform level; Among them, each Z-axis direction motor is independently calculated and compensated to detect the torque at each angular position accordingly.

[0014] Preferably, it also includes: S7) Control the temperature of the photosensitive resin material in the tray to keep the material constant within a specified temperature range; S8) Optimize the tray structure and use inert materials as the release base to reduce the curing time of the bottom contact surface; S9) using a DC motor with a response speed of not less than 200 steps per second and a motion controller with four independent control channels, transmitting instructions via a communication protocol, wherein the motion controller has a preset compensation algorithm to compensate for motor communication delay and mechanical inertia.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1) This application uses a four-axis coplanar Z-axis lifting mechanism equipped with a high-response DC motor, a precision drive screw, and a positioning rod structure to achieve a Z-axis positioning accuracy of ±0.01mm. The four sets of Z-axis lifting mechanisms are symmetrically distributed in a regular matrix. Combined with the rigid frame, they reduce mechanical deformation and optimize space utilization. The diagonal motors adopt a symmetrical steering design. By adjusting the torque distribution through speed regulation, the risk of machine body overturning is effectively reduced and the printing stability is significantly improved. 2) This application installs mechanical sensors at the connection between the printing platform and the suspension to monitor the pressure distribution at the four corners in real time. It then uses a torque balancing algorithm to dynamically adjust the motor drive parameters of the four Z-axis lifting mechanisms to keep the printing platform level. This system can effectively address the stress concentration caused by the high shrinkage rate of elastomeric materials, prevent edge warping and interlayer delamination, and avoid local pressure overload that could cause cracking of the underlying imaging glass, significantly improving the printing success rate. 3) This application uses an inert material as the release layer to reduce the curing time of the bottom contact surface. A variety of interchangeable material trays are designed to accommodate different material properties. Different printing materials can be switched without replacing the release film, significantly improving printing efficiency and material compatibility. The material tray constant temperature system can keep the material constant within a specified temperature range, ensuring the stability of material performance during the printing process. 4) This application sends synchronization commands to the motor driver board via the RS485 protocol, combines a timer to coordinate the timing of the four motor movements, and has anomaly detection and command retransmission functions. It uses a motion controller with four independent control channels and a preset compensation algorithm to compensate for motor communication delays and mechanical inertia, ensuring four-axis synchronization and control accuracy. During the Z-axis initialization process, the system can accurately detect the pressure changes when the printing platform contacts the material tray and accurately record the Z-axis starting coordinate, laying a precise foundation for the subsequent printing process. In summary, the four-axis co-planar high-precision controlled light-curing 3D printer and its control method provided by the present invention effectively solve the problems existing in the existing technology in the field of large-size elastomer printing through innovative designs in mechanical structure, control system, material process, etc., significantly improve printing accuracy, stability and finished product quality, meet the industrial needs of mass production of special elastomer products such as shoe molds, and have significant technological advancement and practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A structural diagram of this application; Figure 2 This is another structural diagram of the present application; Figure 3 A cross-sectional view of the local structure of this application; Figure 4 A cross-sectional view of the local structure after the upper and lower protective boxes are removed for this application; Figure 5 This is a schematic diagram of the printing platform structure of this application; Figure 6 This is a flow chart of the control method of this application.

[0017] In the picture: 1. Base; 2. Display screen; 3. Sink; 4. Top frame; 5. Lifting platform; 6. Suspension rod; 7. Printing platform; 8. Z-axis lifting mechanism; 801. Drive motor; 802. Internal threaded sleeve; 803. Fixed base; 804. Bottom bearing; 805. Drive screw; 806. Positioning sleeve; 807. Positioning rod; 808. Upper protective box; 809. Lower protective box. DETAILED DESCRIPTION

[0018] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0019] In the description of the invention, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," "the other end," and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0020] In the description of the invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "provided with," "connected," etc., should be understood broadly. For example, "connected" may refer to a fixed connection, a detachable connection, or an integral connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0021] See also Figure 1-6 The present invention provides a technical solution: a four-axis coplanar high-precision controlled light-curing 3D printer, including a light-curing 3D printer body, the light-curing 3D printer body including: A base 1, with a display screen 2 embedded in the top of the base 1; The sinking tank 3 is installed on the top of the base 1, and the sinking tank 3 is set directly above the display screen 2; A top frame 4 is provided above the base 1; A lifting platform 5 is movably arranged between the top frame 4 and the base 1. The bottom of the lifting platform 5 is fixedly connected to a plurality of suspension rods 6, and the bottoms of the plurality of suspension rods 6 are fixedly connected to a printing platform 7. Four sets of Z-axis lifting mechanisms 8 are arranged in a regular matrix on the base 1 , the lifting platform 5 and the top frame 4 . The Z-axis lifting mechanisms 8 are suitable for controlling the lifting of the lifting platform 5 .

[0022] Specifically, the light-curing 3D printer is already an existing technology, and its optical lens is arranged in the base 1, which will not be described in detail here.

[0023] Specifically, the four-axis coplanar, high-precision controlled light-curing 3D printer provided by the present invention forms a complete printing mechanical system through the structural design of a base 1, a sink 3, a top frame 4, a lifting platform 5, a cantilever 6, a printing platform 7, and four sets of Z-axis lifting mechanisms 8. The four Z-axis lifting mechanisms 8 are symmetrically arranged in a regular matrix and integrated with the rigid frame, significantly reducing mechanical deformation and optimizing space utilization. The diagonal motors utilize a symmetrical steering design (e.g., two forward and two reverse), which adjusts torque distribution through speed regulation to prevent machine tipping and improve system stability. This design is particularly important when printing large-scale elastomers (such as TPU), as these materials have high shrinkage rates (variable by 0.5%-2%). The combined release forces of multiple layers can easily lead to stress concentration at the corners of the build platform, causing edge warping and interlayer delamination. Conventional single-axis drive systems can cause Z-axis positioning deviations (errors >0.1mm) due to mechanical backlash or lost steps. The present invention utilizes a four-axis coplanar layout, effectively addressing this issue and reducing the risk of build platform tilt and pressure cracking of the bottom glass. The display screen 2 and the sunken trough 3 embedded in the top of the base 1 enable the light projection system to accurately project light onto the printed material. The sunken trough 3, positioned directly above the display screen 2, creates an efficient light-curing space. The lifting platform 5 is connected to the printing platform 7 via a suspension rod 6. The coordinated control of four Z-axis lifting mechanisms 8 enables precise Z-axis lifting and lowering, paving the way for high-precision printing. This structural design is particularly well-suited for the 3D printing needs of mass-produced large-scale elastomeric parts, such as shoe molds, effectively improving print success rates and ensuring consistent product quality.

[0024] Reference Manual Figure 5 The top of the printing platform 7 is a quadrangular pyramid structure. Specifically, in an ascending light-curing printer, the printing platform 7 must first descend into the resin liquid in the sink 3. The molding process is a process in which the printing platform 7 is lifted upward layer by layer. The quadrangular pyramid structure causes the surface area of ​​the printing platform 7 to gradually decrease from the center to the edge. When the printing platform 7 rises from the resin liquid level, the liquid can naturally flow down along the inclined surface, significantly reducing the amount of resin liquid remaining on the surface and avoiding material waste and subsequent contamination caused by liquid residue. This "self-draining" property is particularly important for high-viscosity photosensitive resin materials, reducing the waiting time after each layer of printing and improving printing efficiency. At the same time, the quadrangular pyramid structure effectively reduces stress concentration in the edge area when printing large-scale elastomers, reducing the risk of warping caused by material shrinkage. When printing high-shrinkage materials such as TPU (shrinkage differences can reach 0.5%-2%), the quadrangular pyramid shape promotes uniform stress distribution and reduces the risk of edge warping.

[0025] Reference Manual Figure 1-4 , the Z-axis lifting mechanism 8 includes: The driving motor 801 is mounted on the top of the top frame 4; The internal threaded sleeve 802 is fixedly installed in the lifting platform 5; The fixed base 803 is fixed to the top of the base 1 by bolts; Bottom bearing 804, fixed in the top of fixed base 803; The transmission screw 805 is connected to the inner side of the internal threaded sleeve 802 through a threaded structure. The top of the transmission screw 805 is fixedly connected to the motor shaft of the drive motor 801, and the bottom of the transmission screw 805 is fixed to the inner ring of the bottom bearing 804; The positioning sleeve 806 is fixedly installed in the lifting platform 5; Positioning rod 807, fixed between the bottom of top frame 4 and the top of base 1; The positioning rod 807 is loosely fitted into the positioning sleeve 806 , and the positioning rod 807 is arranged parallel to the transmission screw 805 .

[0026] Specifically, the design of the positioning sleeve 806 and the positioning rod 807 constitutes a lifting guide system, which prevents the lifting platform 5 from deflecting or swinging during movement, ensuring that the printing platform 7 always remains in a horizontal state.

[0027] The Z-axis lifting mechanism 8 also includes: Two sets of upper protection boxes 808 are fixed to the top of the lifting platform 5 by bolts; The lower protective box 809 is fixed to the top of the base 1 by bolts; Among them, the two groups of upper protective boxes 808 are spliced ​​in half to form a box body structure cover arranged on the outer side of the upper end of the internal thread sleeve 802 and the positioning sleeve 806, and the lower protective box 809 cover is arranged on the outer side of the fixed base 803.

[0028] Specifically, the upper protective box 808 and the lower protective box 809 respectively form a box structure to protect the outer side of the upper end of the internal threaded sleeve 802, the positioning sleeve 806, and the outer side of the fixed base 803. This design firstly effectively prevents external dust, splashes of light-curing resin and other impurities from entering the transmission system, avoiding the reduction in mechanical precision and shortened service life due to the accumulation of impurities. Secondly, the design of the protective box isolates the ultraviolet light in the light-curing environment, preventing ultraviolet light from reaching the transmission components and causing material aging and performance degradation. The upper protective box 808 adopts a half-spliced ​​structure, which is convenient for disassembly and inspection during equipment maintenance, thereby improving maintenance efficiency and convenience.

[0029] The Z-axis lift mechanism 8 also includes a mechanical sensor, located at the connection between the print platform 7 and the suspension 6. The sensor is suitable for real-time monitoring of the pressure distribution at the four corners of the print platform 7. Specifically, during the printing process, especially when printing high-shrinkage materials such as TPU (shrinkage differences can reach 0.5%-2%), the stacked layers generate cumulative release forces, leading to stress concentrations at the four corners of the build platform. Conventional printers lack real-time monitoring capabilities and are unable to promptly detect and adjust for this uneven stress distribution. The mechanical sensor system of the present invention can capture pressure changes in real time, with an accurate measurement range of 0-10N and a resolution of up to 0.01N, capable of detecting even tiny pressure fluctuations. When the print platform 7 contacts the material tray, the mechanical sensor accurately senses the pressure changes at the moment of contact, providing data support for accurate positioning of the Z-axis initial position, avoiding the risk of excessive pressure causing the underlying glass to crack under pressure. Furthermore, during the printing process, the sensor continuously monitors the pressure trends at the four corners, providing real-time data input for the torque balancing algorithm. Based on this data, the system dynamically adjusts the motor drive parameters of the four sets of Z-axis lift mechanisms 8 to achieve precise and balanced lifting and lowering of the print platform 7. This closed-loop feedback control mechanism significantly improves the stability and reliability of the printing process, especially during long printing periods. It can effectively compensate for stress changes caused by factors such as temperature changes and material shrinkage, prevent edge warping and interlayer delamination, and improve the success rate of large-scale elastomer printing and product quality consistency. It is especially suitable for mass production of products such as shoe molds that require high precision.

[0030] A control method for a four-axis coplanar high-precision controlled light-curing 3D printer is provided, which is applied to a four-axis coplanar high-precision controlled light-curing 3D printer, comprising the following steps: S1) receiving printing task instructions, parsing 3D model files, and generating layered slice data; S2) Initializing the Z-axis position and adjusting the printing platform 7 to the initial height via the four sets of Z-axis lifting mechanisms 8; S3) Turn on the light source projection system and project each layer of pattern onto the photosensitive resin material in the tray according to the slice data; S4) monitoring the pressure distribution at the four corners of the printing platform 7 in real time through a force sensor; S5) Based on the feedback data from the mechanical sensors, a torque balancing algorithm is used to dynamically adjust the motor drive parameters of the four Z-axis lifting mechanisms 8 to achieve balanced lifting of the printing platform 7; S6) After the curing of the current layer is completed, the four Z-axis lifting mechanisms 8 are controlled to synchronously lift the printing platform 7 to the next layer printing height, and steps S3 to S5 are repeated until the entire printing task is completed; Among them, the position of each motor is monitored by an encoder or grating ruler, the controller adjusts the output pulse to reduce the cumulative error, and the torque balancing algorithm balances the load of each motor and reduces the eccentric load caused by differences in mechanical structure.

[0031] Specifically, during the Z-axis initialization phase, four Z-axis lift mechanisms 8 work together to precisely locate the printing starting point. The light projection system accurately projects each layer's pattern based on the slice data, coordinating with the photosensitive resin material in the tray for precise curing. Mechanical sensors monitor the pressure distribution at the four corners of the print platform 7 in real time, providing data support for the torque balancing algorithm. This algorithm dynamically adjusts the motor drive parameters of the four Z-axis lift mechanisms 8 to ensure the print platform 7 remains level throughout the printing process. The system uses encoders or linear scales to monitor the position of each motor, and the controller adjusts the output pulses to minimize cumulative error, achieving Z-axis positioning accuracy of ±0.01mm. This is crucial for printing fine structures and ensuring interlayer bonding strength. By balancing the loads on each motor, the torque balancing algorithm reduces unbalanced loads caused by mechanical structure variations and effectively prevents tilting and deformation of the print platform 7 during movement. This method is particularly suitable for printing large-scale elastomer products made from high-shrinkage materials (e.g., TPU, where shrinkage can vary by 0.5%-2%), effectively addressing the cumulative release forces and stress concentrations caused by stacking multiple layers. Practice has proved that after adopting this control method, the success rate of printing large-size elastomers has increased by about 40%, the product dimensional accuracy has increased by 30%, and the production efficiency and product quality stability have been significantly improved, providing reliable technical support for the mass production of high-quality shoe molds and other products.

[0032] In step S2, the method for initializing the Z-axis position includes: S2.1) Control the four Z-axis lifting mechanisms 8 to drive the printing platform 7 to slowly descend; S2.2) Detecting pressure changes between the printing platform 7 and the material tray using a force sensor; S2.3) When the pressure exceeds the preset threshold, the machine stops descending and records the current Z-axis coordinate as the printing starting point; Among them, synchronization instructions are sent to the motor driver board through the RS485 protocol, and the timer is combined to coordinate the timing of the four motor actions, and it has the functions of abnormal detection and instruction retransmission.

[0033] Specifically, in traditional stereolithography 3D printing, the determination of the Z-axis starting position often relies on mechanical limit switches or simple visual judgment, which is inaccurate and easily affected by environmental and human factors. This can lead to inconsistent first-layer thickness, compromising overall print quality. In this method, four Z-axis lift mechanisms 8 receive synchronization commands via the RS485 protocol. Timers coordinate the precise timing of the four motors' movements, ensuring a smooth and uniform descent of the print platform 7. This descent speed is 0.1-0.5 mm / s, preventing potential impact damage from rapid contact. The force sensor, with a sensitivity of up to 0.01 N, accurately captures the subtle pressure changes during initial contact between the print platform 7 and the material tray. When the detected pressure exceeds a preset threshold (typically set at 0.5-1 N), the system immediately stops descending and precisely records the current Z-axis coordinate as the print starting point, achieving a positioning accuracy of ±0.01 mm. The RS485 communication protocol utilizes differential signal transmission, offering strong anti-interference capabilities and meeting the stability requirements of device control. The system also implements anomaly detection and command resending capabilities. When abnormal conditions such as communication timeouts and verification failures are detected, the system automatically resends commands to ensure accurate control. This precise Z-axis initial positioning method allows the first layer of print thickness to be controlled within an error range of ±0.02mm, significantly improving the adhesion and flatness of the printed substrate and reducing print failures caused by uneven first layers. It is particularly suitable for printing large-scale elastomer products with stringent precision requirements.

[0034] In step S5, the torque balancing algorithm specifically includes: S5.1) Calculate the pressure difference at the four corners of the printing platform 7; S5.2) Calculate the compensation amounts for the corresponding motors of the four Z-axis lifting mechanisms 8 based on the pressure differences; S5.3) Send compensation parameters to the motor driver board to adjust the speed and position of each motor to keep the printing platform 7 level; Among them, each Z-axis direction motor is independently calculated and compensated to detect the torque at each angular position accordingly.

[0035] Specifically, during the pressure differential calculation phase, the system collects pressure data from the four corners of the print platform 7 and calculates deviations from an ideal uniform state. The deviation sensitivity is set to ±0.1N, allowing it to detect even the slightest pressure imbalance. Based on these pressure differentials, the system uses a compensation algorithm to calculate the required adjustments for each motor in the four Z-axis lift mechanisms 8. This compensation algorithm utilizes the proportional-integral-derivative (PID) control principle, combined with a four-axis coupling matrix, to convert pressure deviations into precise motor position and speed compensations. The motor compensation resolution is as high as 0.005mm, enabling fine-tuning. The system transmits these compensation parameters to each motor via the motor driver board, adjusting their speed and position to maintain precise leveling of the print platform 7. Specifically, in the Z-axis, each motor independently calculates and compensates, achieving precise coordinated control of the four corner positions. This approach is particularly important when printing materials with high shrinkage rates (such as TPU, which has shrinkage variations of 0.5%-2%). It effectively addresses platform tilt and localized stress concentrations caused by uneven material shrinkage. This effectively improves the precision and mechanical property consistency of the finished product.

[0036] The control method for a four-axis co-planar high-precision light-curing 3D printer further includes: S7) Control the temperature of the photosensitive resin material in the tray to keep the material constant within a specified temperature range; S8) Optimize the tray structure and use inert materials as the release base to reduce the curing time of the bottom contact surface; S9) Using a DC motor with a response speed of not less than 200 steps per second and a motion controller with four independent control channels, transmitting instructions through a communication protocol, the motion controller having a preset compensation algorithm to compensate for motor communication delay and mechanical inertia.

[0037] Specifically, the system maintains a constant temperature range for photosensitive resin materials (typically 25-35°C, with an accuracy of ±0.5°C), which is crucial for photocurable materials. Excessively low temperatures increase material viscosity, affecting fluidity and uniformity; excessively high temperatures affect the curing reaction rate and mechanical properties of the finished product. Constant temperature control ensures stable rheological properties and photochemical reactivity throughout the printing process, enhancing controllability and repeatability. The optimized tray structure utilizes inert materials (such as polytetrafluoroethylene or silicone) as the release layer. These materials have extremely low surface energy and excellent chemical stability, significantly reducing adhesion between the resin and the tray base and shortening the curing time at the contact surface, thereby increasing printing speed. The system's DC motors feature a high-performance response speed of at least 200 steps per second, enabling rapid response to control commands and precise positioning. The motion controller, with four independent control channels, simultaneously processes the motion parameters of all four motors, enabling efficient command transmission via a communication protocol. The controller integrates a preset compensation algorithm to compensate for motor communication delays and mechanical inertia (position overshoot of approximately 0.01-0.05mm during start-stop processes) in real time, significantly improving the system's dynamic response and positioning accuracy. The synergistic effect of these three technical measures ensures the printing system exhibits superior performance and stability when processing large-scale elastomer products, shortening print times and improving positioning accuracy.

[0038] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A four-axis coplanar high-precision controlled light-curing 3D printer, comprising a light-curing 3D printer body, characterized in that: The light-curing 3D printer body includes: A base (1), wherein a display screen (2) is embedded in the top of the base (1); A sinking trough (3) is installed on the top of the base (1), and the sinking trough (3) is arranged directly above the display screen (2); A top frame (4) is arranged above the base (1); A lifting platform (5) is movably arranged between the top frame (4) and the base (1), wherein the bottom of the lifting platform (5) is fixedly connected to a plurality of groups of suspension rods (6), and the bottoms of the plurality of groups of suspension rods (6) are fixedly connected to a printing platform (7); Four groups of Z-axis lifting mechanisms (8) are arranged in a regular matrix on the base (1), the lifting platform (5) and the top frame (4), and the Z-axis lifting mechanisms (8) are suitable for controlling the lifting and lowering of the lifting platform (5).

2. The four-axis coplanar high-precision controlled light-curing 3D printer according to claim 1, characterized in that: The top of the printing platform (7) is a quadrangular pyramid structure.

3. The four-axis coplanar high-precision controlled light-curing 3D printer according to claim 1, characterized in that: The Z-axis lifting mechanism (8) comprises: A driving motor (801) is mounted on the top of the top frame (4); An internal threaded sleeve (802) is fixedly inserted into the lifting platform (5); A fixed base (803) is fixed to the top of the base (1) by bolts; A bottom bearing (804) is fixed inside the top of the fixed base (803); A transmission screw (805) is connected to the inner side of the internal threaded sleeve (802) through a threaded structure, the top of the transmission screw (805) is fixedly connected to the motor shaft of the drive motor (801), and the bottom of the transmission screw (805) is fixed in the inner ring of the bottom bearing (804); A positioning sleeve (806) is fixedly inserted into the lifting platform (5); A positioning rod (807) is fixed between the bottom of the top frame (4) and the top of the base (1); The positioning rod (807) is loosely fitted into the positioning sleeve (806), and the positioning rod (807) is arranged parallel to the transmission screw (805).

4. The four-axis coplanar high-precision controlled light-curing 3D printer according to claim 3, characterized in that: The Z-axis lifting mechanism (8) further comprises: Two sets of upper protection boxes (808) are fixed to the top of the lifting platform (5) by bolts; A lower protective box (809) is fixed to the top of the base (1) by bolts; The two groups of upper protective boxes (808) are spliced ​​in half to form a box structure, the cover of which is arranged on the outer side of the upper end of the internal threaded sleeve (802) and the positioning sleeve (806), and the cover of the lower protective box (809) is arranged on the outer side of the fixed base (803).

5. The four-axis coplanar high-precision controlled light-curing 3D printer according to claim 1, characterized in that: The Z-axis lifting mechanism (8) further includes a mechanical sensor, which is arranged at the connection between the printing platform (7) and the suspension rod (6), and is suitable for real-time monitoring of the pressure distribution at the four corners of the printing platform (7).

6. A control method for a four-axis coplanar high-precision controlled light-curing 3D printer, applied to the four-axis coplanar high-precision controlled light-curing 3D printer according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1) receiving printing task instructions, parsing 3D model files, and generating layered slice data; S2) initializing the Z-axis position, and adjusting the printing platform (7) to an initial height through the four sets of Z-axis lifting mechanisms (8); S3) Turn on the light source projection system and project each layer of pattern onto the photosensitive resin material in the tray according to the slice data; S4) monitoring the pressure distribution at the four corners of the printing platform (7) in real time through a mechanical sensor; S5) Based on the feedback data from the mechanical sensor, a torque balancing algorithm is used to dynamically adjust the motor drive parameters of the four groups of Z-axis lifting mechanisms (8) to achieve balanced lifting of the printing platform (7); S6) After the curing of the current layer is completed, the four groups of Z-axis lifting mechanisms (8) are controlled to synchronously lift the printing platform (7) to the printing height of the next layer, and steps S3 to S5 are repeated until the entire printing task is completed; The position of each motor is monitored by an encoder or a grating ruler, and the controller adjusts the output pulse to reduce the cumulative error. The torque balancing algorithm balances the load of each motor and reduces the eccentric load caused by the difference in mechanical structure.

7. The control method for a four-axis coplanar high-precision light-curing 3D printer according to claim 6, characterized in that: In step S2, the method for initializing the Z-axis position includes: S2.1) controlling the four Z-axis lifting mechanisms (8) to drive the printing platform (7) to slowly descend; S2.2) detecting pressure changes when the printing platform (7) contacts the material tray using a mechanical sensor; S2.3) When the pressure exceeds the preset threshold, the machine stops descending and records the current Z-axis coordinate as the printing starting point; Among them, synchronization instructions are sent to the motor driver board through the RS485 protocol, and the timer is combined to coordinate the timing of the four motor actions, and it has the functions of abnormal detection and instruction retransmission.

8. The control method for a four-axis coplanar high-precision light-curing 3D printer according to claim 6, characterized in that: In step S5, the torque balancing algorithm specifically includes: S5.1) calculating the pressure difference at the four corners of the printing platform (7); S5.2) calculating the compensation amounts of the motors corresponding to the four groups of Z-axis lifting mechanisms (8) according to the pressure difference; S5.3) sending compensation parameters to the motor drive board to adjust the speed and position of each motor so that the printing platform (7) remains level; Among them, each Z-axis direction motor is independently calculated and compensated to detect the torque at each angular position accordingly.

9. The control method for a four-axis coplanar high-precision light-curing 3D printer according to claim 6, characterized in that: Also includes: S7) Control the temperature of the photosensitive resin material in the tray to keep the material constant within a specified temperature range; S8) Optimize the tray structure and use inert materials as the release base to reduce the curing time of the bottom contact surface; S9) using a DC motor with a response speed of not less than 200 steps per second and a motion controller with four independent control channels, transmitting instructions via a communication protocol, wherein the motion controller has a preset compensation algorithm to compensate for motor communication delay and mechanical inertia.

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