3D printer based on dynamic extrusion force and precise temperature control and filament diameter control method

Abstract

A 3D printer based on dynamic extrusion force and precise temperature control and a method for controlling the diameter of a filament, specifically relating to the field of biomanufacturing technology. The present invention is intended to solve the problems of low diameter accuracy and uncontrollable printing structure of existing 3D printing filaments of polymer materials. The 3D printer of the present invention includes a cylinder, a tension and pressure sensor, a nozzle push rod, a printing nozzle and a temperature control device. The cylinder is arranged vertically downward, and the rod end of the cylinder is connected to the top of the nozzle push rod through a tension and pressure sensor. The lower end of the nozzle push rod is inserted into the channel inside the printing nozzle and can be moved up and down. The temperature control device is arranged on the outside of the printing nozzle and can heat the printing nozzle. The method for controlling the diameter of a filament includes: extrusion 3D printing; repeated 3D printing experiments; data analysis; parameter optimization; verification.

Description

Technical Field

[0001] The present invention relates to the field of biomanufacturing technology, and in particular to a 3D printer based on dynamic extrusion force and precise temperature control and a method for controlling filament diameter. Background Art

[0002] Because bio-inks are mostly high-molecular polymers with complex rheological properties, they place stringent demands on the printing environment. Improper printing parameters can cause the filaments to expand, deform, and even break. This can lead to a significant deviation between the actual filament diameter and the designed value. As the fundamental building block of three-dimensional structures, these errors can be amplified during the 3D printing process, leading to significant errors in the overall structure and making it difficult to achieve high-precision tissue and organ construction.

[0003] Currently, to achieve the desired filament diameter accuracy, key printing parameters (such as extrusion force and printing temperature) are often repeatedly adjusted through trial and error until the extruded filament diameter meets the required accuracy. However, existing printing equipment is typically driven by compressed air, making it impossible to dynamically control the extrusion force changes. Furthermore, when printing under high-temperature conditions, 3D printing nozzles often experience heat loss and low heat transfer efficiency. This causes the temperature at the nozzle to deviate from the ideal printing temperature, reducing the temperature control accuracy during the 3D printing process. These issues make high-precision filament printing difficult to achieve using existing 3D printing processes. Using trial and error alone is not only time-consuming but also lacks reliability and repeatability. Therefore, to obtain filaments with the desired diameter and high precision, there is an urgent need for a method to dynamically control the extrusion force during the printing process and to precisely control the printing temperature, thereby achieving precise control of the 3D printed filament diameter. Summary of the Invention

[0004] In order to solve the problems of low diameter accuracy and uncontrollable printing structure of existing polymer material 3D printing filaments, the present invention proposes a 3D printer based on dynamic extrusion force and precise temperature control and a filament diameter control method.

[0005] The technical solution adopted by the present invention to solve the above technical problems is:

[0006] A 3D printer based on dynamic extrusion force and precise temperature control includes a cylinder, a tension and pressure sensor, a nozzle push rod, a print nozzle and a temperature control device. The cylinder is arranged vertically downward, and the rod end of the cylinder is connected to the top of the nozzle push rod through the tension and pressure sensor. The lower end of the nozzle push rod is inserted into the channel inside the print nozzle and can move up and down. The temperature control device is arranged on the outside of the print nozzle and can heat the print nozzle.

[0007] Furthermore, it also includes a fixing plate, which is vertically arranged, the cylinder is fixedly connected to the front end surface of the fixing plate, and the printing nozzle is arranged directly below the cylinder and fixedly connected to the fixing plate.

[0008] Furthermore, the tension and pressure sensor is fixed on the sensor fixing part, the rod end of the cylinder is fixed to the sensor fixing part, the top end of the nozzle push rod is fixed to the nozzle push rod fixing part, and the tension and pressure sensor is fixed to the nozzle push rod fixing part.

[0009] Furthermore, the temperature control device includes a temperature control housing and a heating device. The heating device is fixed in the temperature control housing and arranged near the nozzle of the print head. A temperature controller is provided on the temperature control housing. The temperature controller is electrically connected to the heating device to realize temperature control and adjustment of the heating device.

[0010] A method for controlling filament diameter of a 3D printer based on dynamic extrusion force and precise temperature control, the method comprising the following steps:

[0011] Step 1: Extrusion 3D printing: Assemble a 3D printer that can achieve high-precision temperature control and dynamic control of extrusion force. Then, load the target material into the interior of the print nozzle, and control the temperature of the print nozzle through the temperature control device, thereby controlling the heating temperature of the target material. Then, external air is supplied to make the rod end of the cylinder move vertically back and forth, driving the nozzle push rod to move up and down in the internal channel of the print nozzle, thereby pushing and extruding the target material, completing the 3D printing process.

[0012] Step 2: Repeat the 3D printing experiment: Repeat the above 3D printing process at different temperatures and extrusion pressures, 3D print the target material respectively, and record the filament diameter at different temperatures and extrusion pressures;

[0013] Step 3: Data Analysis: Organize the experimental data and use the temperature, extrusion pressure, and filament diameter data from different experimental groups as x, y, and z coordinate values, respectively, to generate a set of three-dimensional histograms. Import the experimental data from the three-dimensional histograms into analysis software, and fit the curves of filament diameter changes under different temperatures and extrusion pressures to obtain a prediction model for controlling filament diameter by adjusting the two printing parameters of temperature and extrusion pressure.

[0014] Step 4: Parameter Optimization: The prediction model can be used to optimize the printing parameters: first determine the target filament diameter, and then select the corresponding temperature and extrusion pressure from the surface of the prediction model based on the filament diameter as the printing parameters with high filament accuracy for the target material;

[0015] Step 5, Verification: By using the high filament output precision printing parameters to perform 3D printing on the target material, it is determined whether the printing precision meets the requirements, thus completing the verification of the 3D printer filament output diameter control method based on dynamic extrusion force and precise temperature control.

[0016] Furthermore, the tension and pressure sensor can record and feedback the extrusion force applied to the nozzle push rod in real time, and the real-time data of the tension and pressure sensor can be adjusted by controlling the reciprocating movement of the cylinder to achieve control of the extrusion force during the 3D printing process.

[0017] Furthermore, the heating device in the temperature control device is arranged close to the nozzle of the printing nozzle to heat the target material, and the temperature of the heating device is controlled and adjusted by the temperature controller to control the temperature of the printing nozzle, thereby controlling the heating temperature of the target material.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] This invention addresses the uncontrollable process and low filament diameter precision of polymer 3D printing in the biomanufacturing field. By constructing a 3D printing device that can independently control the dynamic extrusion force and printing temperature, it enables 3D printing of target materials under different parameters. Printing accuracy is recorded, and a printing accuracy prediction model based on experimental data is constructed to optimize printing parameters, achieving filament printing with high diameter accuracy.

[0020] The present invention is based on the design of printing equipment and mathematical prediction model methods to perform high-precision control on the diameter of 3D printing filaments; this design method can achieve high-precision printing of polymer filaments, the design process is simple and clear, and the efficiency of obtaining optimal parameters is high, which is of great significance for the high-precision in vitro construction of tissue organs with complex structures. By building a 3D printing device that can control temperature and extrusion force separately, the relationship between printing accuracy and process parameters during the printing process is explored, wherein dynamic extrusion force control is achieved by controlling the movement of the cylinder; by improving the heat transfer efficiency inside the printing nozzle, the printing temperature control accuracy is greatly improved: when the structure of the present invention is not used, the temperature control error at the nozzle is 28%, and when the structure of the present invention is used, the temperature control error at the nozzle is reduced to 6.2%. The temperature control device used can control the printing temperature accuracy within. The most commonly used polymer in biomanufacturing, poly (L-lactide-caprolactone) (PLCL), is used as the printing material to verify the feasibility of the designed method: such as Figure 3 The results of the printing experiment are shown below. The experimental results were analyzed by computer and fitted as shown below. Figure 4 The prediction model shown in Figure 2 is used. Parameters are optimized based on the prediction model and filament printing experiments are performed, and the final result is Figure 5The filaments shown have a diameter accuracy of less than 5μm. Without this method, the absolute diameter error of the printed PLCL filaments can reach 22μm. With this method, the absolute error is reduced by 77.3%, effectively improving the diameter accuracy of the 3D printed filaments. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the structure of the 3D printer based on dynamic extrusion force and precise temperature control in the present invention;

[0022] Figure 2 This is a flow chart of a method for controlling the filament diameter of a 3D printer based on dynamic extrusion force and precise temperature control in the present invention;

[0023] Figure 3 is the diameter of the 3D printed PLCL filament under different temperatures and extrusion pressures in the present invention;

[0024] Figure 4 It is the PLCL filament accuracy prediction model under different temperatures and extrusion pressures in the present invention;

[0025] Figure 5 The high-precision PLCL filaments of the present invention have different diameters.

[0026] The reference numerals include: 1-cylinder, 2-sensor fixing part, 3-tension pressure sensor, 4-nozzle push rod fixing part, 5-nozzle push rod, 6-printing nozzle, 7-temperature control device. DETAILED DESCRIPTION

[0027] Specific implementation method 1: Combination Figure 1 To illustrate this embodiment, the 3D printer based on dynamic extrusion force and precise temperature control described in this embodiment includes a cylinder 1, a tension and pressure sensor 3, a nozzle push rod 5, a printing nozzle 6 and a temperature control device 7. The cylinder 1 is arranged vertically downward, and the rod end of the cylinder 1 is connected to the top of the nozzle push rod 5 through the tension and pressure sensor 3. The lower end of the nozzle push rod 5 is inserted into the channel inside the printing nozzle 6 and can move up and down. The temperature control device 7 is arranged on the outside of the printing nozzle 6 and can heat the printing nozzle 6.

[0028] This embodiment develops a novel 3D printing device that achieves high-precision temperature control and dynamic extrusion force control. The target material is loaded into a print head 6, and the temperature of the print head 6 is controlled by a temperature control device 7, thereby controlling the heating temperature of the target material. Subsequently, an external air supply causes the rod end of the cylinder 1 to reciprocate vertically, and this motion is transmitted to the print head push rod 5, pushing and extruding the target material, completing the 3D printing process.

[0029] The connection methods in this embodiment include but are not limited to threaded connection, welding, pin connection, etc.

[0030] Specific implementation method 2: Combination Figure 1 This embodiment describes a 3D printer based on dynamic extrusion force and precise temperature control, further comprising a vertically disposed fixed plate 8, a cylinder 1 fixedly connected to the front end of the fixed plate 8, and a print head 6 disposed directly below the cylinder 1 and fixedly connected to the fixed plate 8. Undisclosed technical features in this embodiment are the same as those in the first embodiment.

[0031] Specific implementation method three: Combination Figure 1 This embodiment describes a tension and pressure sensor 3 fixed to the sensor fixture 2. The rod end of the cylinder 1 is fixed to the sensor fixture 2. The top end of the nozzle push rod 5 is fixed to the nozzle push rod fixture 4. The tension and pressure sensor 3 is fixed to the nozzle push rod fixture 4. The undisclosed technical features of this embodiment are the same as those of the second specific embodiment.

[0032] The rod end at the lower end of the cylinder 1 is connected to the sensor fixing part 2, the lower end of the sensor fixing part 2 is connected to the tension and pressure sensor 3, and the bottom end of the tension and pressure sensor 3 is connected to the top end of the nozzle push rod 5.

[0033] Specific implementation method four: Combination Figure 1 In this embodiment, the temperature control device 7 includes a temperature control housing and a heating device. The heating device is fixedly mounted within the temperature control housing and positioned near the nozzle of the print head 6. The temperature control housing is provided with a temperature controller electrically connected to the heating device to control and adjust the temperature of the heating device. The undisclosed technical features of this embodiment are the same as those of the first embodiment.

[0034] The heating device inside the temperature control device 7 includes but is not limited to a heating rod, a heating wire, etc., and the heating device is installed near the nozzle.

[0035] During this process, the temperature control shell is made of a metal material with extremely strong thermal conductivity, and the heating device is installed at the bottom of the temperature control shell. By improving the heat conduction efficiency, high-efficiency heating of the bottom of the 3D printing nozzle is achieved, which reduces the temperature loss at the bottom of the nozzle during printing and improves the temperature control accuracy at the printing nozzle. At the same time, the tension and pressure sensor 3 can record and feedback the extrusion force applied to the nozzle push rod 4 in real time. By controlling the reciprocating motion of the cylinder 1 to adjust the real-time data of the tension and pressure sensor 3, the extrusion force of the 3D printing process can be controlled.

[0036] Specific implementation method five: Combination Figures 1 to 5 This embodiment describes a method for controlling the filament diameter of a 3D printer based on dynamic extrusion force and precise temperature control, the method comprising the following steps:

[0037] Step 1: Extrusion 3D printing: Assemble a 3D printer that can achieve high-precision temperature control and dynamic control of extrusion force. Then, load the target material into the interior of the print nozzle 6, and control the temperature of the print nozzle 6 through the temperature control device 7, thereby controlling the heating temperature of the target material. Then, external air is supplied to make the rod end of the cylinder 1 move vertically back and forth, driving the nozzle push rod 5 to move up and down in the internal channel of the print nozzle 6, thereby pushing and extruding the target material, completing the 3D printing process.

[0038] Step 2: Repeat the 3D printing experiment: Repeat the above 3D printing process at different temperatures and extrusion pressures, 3D print the target material respectively, and record the filament diameter at different temperatures and extrusion pressures;

[0039] Step 3: Data Analysis: Organize the experimental data and use the temperature, extrusion pressure, and filament diameter data from different experimental groups as x, y, and z coordinate values, respectively, to generate a set of three-dimensional histograms. Import the experimental data from the three-dimensional histograms into analysis software, and fit the curves of filament diameter changes under different temperatures and extrusion pressures to obtain a prediction model for controlling filament diameter by adjusting the two printing parameters of temperature and extrusion pressure.

[0040] Step 4: Parameter Optimization: The prediction model can be used to optimize the printing parameters: first determine the target filament diameter, and then select the corresponding temperature and extrusion pressure from the surface of the prediction model based on the filament diameter as the printing parameters with high filament accuracy for the target material;

[0041] Step 5, Verification: By using the high filament output precision printing parameters to perform 3D printing on the target material, it is determined whether the printing precision meets the requirements, thus completing the verification of the 3D printer filament output diameter control method based on dynamic extrusion force and precise temperature control.

[0042] Specific implementation method six: combination Figures 1 to 5 This embodiment describes the tension and pressure sensor 3, which can record and feedback the extrusion force applied to the nozzle push rod 5 in real time. By controlling the reciprocating movement of the cylinder 1 and adjusting the real-time data from the tension and pressure sensor 3, the extrusion force during the 3D printing process can be controlled. The undisclosed technical features of this embodiment are the same as those of the fifth embodiment.

[0043] Specific implementation method seven: combination Figures 1 to 5 In this embodiment, the heating device in the temperature control device 7 is positioned near the nozzle of the print head 6 to heat the target material. The temperature controller controls and adjusts the temperature of the heating device to control the temperature of the print head 6, and thus the heating temperature of the target material. The undisclosed technical features of this embodiment are the same as those of the fifth embodiment.

[0044] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for controlling the diameter of a filament output from a 3D printer based on dynamic extrusion force and precise temperature control, wherein the 3D printer based on dynamic extrusion force and precise temperature control comprises a cylinder (1), a tension and pressure sensor (3), a nozzle push rod (5), a printing nozzle (6), and a temperature control device (7), wherein the cylinder (1) is arranged vertically downward, the rod end of the cylinder (1) is connected to the top end of the nozzle push rod (5) through the tension and pressure sensor (3), the lower end of the nozzle push rod (5) is inserted into a channel inside the printing nozzle (6) and can move up and down, and the temperature control device (7) is arranged outside the printing nozzle (6) and can heat the printing nozzle (6); The 3D printer based on dynamic extrusion force and precise temperature control further comprises a fixed plate (8), the fixed plate (8) being arranged vertically, the cylinder (1) being fixedly connected to the front end surface of the fixed plate (8), and the print head (6) being arranged directly below the cylinder (1) and fixedly connected to the fixed plate (8); Its characteristics are: The method comprises the following steps: Step 1, extrusion 3D printing: assemble a 3D printer that can achieve high-precision temperature control and dynamic control of extrusion force, then load the target material into the interior of the print nozzle (6), and control the temperature of the print nozzle (6) through the temperature control device (7), thereby controlling the heating temperature of the target material, and then supply air externally to make the rod end of the cylinder (1) move vertically back and forth, driving the nozzle push rod (5) to move up and down in the internal channel of the print nozzle (6), thereby achieving the pushing and extrusion of the target material, and completing the 3D printing process; Step 2: Repeat the 3D printing experiment: Repeat the above 3D printing process at different temperatures and extrusion pressures, 3D print the target material respectively, and record the filament diameter at different temperatures and extrusion pressures; Step 3: Data Analysis: Organize the experimental data and use the temperature, extrusion pressure, and filament diameter data from different experimental groups as x, y, and z coordinate values, respectively, to generate a set of three-dimensional histograms. Import the experimental data from the three-dimensional histograms into analysis software, and fit the curves of filament diameter changes under different temperatures and extrusion pressures to obtain a prediction model for controlling filament diameter by adjusting the two printing parameters of temperature and extrusion pressure. Step 4: Parameter Optimization: The prediction model can be used to optimize the printing parameters: first determine the target filament diameter, and then select the corresponding temperature and extrusion pressure from the surface of the prediction model based on the filament diameter as the printing parameters with high filament accuracy for the target material; Step 5, Verification: By using the high filament output precision printing parameters to perform 3D printing on the target material, it is determined whether the printing precision meets the requirements, thus completing the verification of the 3D printer filament output diameter control method based on dynamic extrusion force and precise temperature control.

2. The method for controlling the filament diameter of a 3D printer based on dynamic extrusion force and precise temperature control according to claim 1, characterized in that: The tension pressure sensor (3) is fixedly connected to the sensor fixing member (2), the rod end of the cylinder (1) is fixedly connected to the sensor fixing member (2), the top end of the nozzle push rod (5) is fixedly connected to the nozzle push rod fixing member (4), and the tension pressure sensor (3) is fixedly connected to the nozzle push rod fixing member (4).

3. The method for controlling the filament diameter of a 3D printer based on dynamic extrusion force and precise temperature control according to claim 1, wherein: The temperature control device (7) comprises a temperature control housing and a heating device, wherein the heating device is fixedly connected to the temperature control housing and is arranged close to the nozzle of the print head (6), and a temperature controller is provided on the temperature control housing. The temperature controller is electrically connected to the heating device to realize temperature control and adjustment of the heating device.

4. The method for controlling the filament diameter of a 3D printer based on dynamic extrusion force and precise temperature control according to claim 1, wherein: The pulling and pressure sensor (3) can record and feedback the extrusion force applied to the nozzle push rod (5) in real time, and the real-time data of the pulling and pressure sensor (3) can be adjusted by controlling the reciprocating movement of the cylinder (1), thereby realizing the control of the extrusion force during the 3D printing process.

5. The method for controlling the filament diameter of a 3D printer based on dynamic extrusion force and precise temperature control according to claim 1, characterized in that: The heating device in the temperature control device (7) is arranged close to the nozzle of the printing nozzle (6) to heat the target material. The temperature of the heating device is controlled and adjusted by the temperature controller, thereby controlling the temperature of the printing nozzle (6) and further controlling the heating temperature of the target material.

Images