A method and device for automatically correcting the position of a 3D printing nozzle

Abstract

The present invention relates to a method and device for automatic position correction of a 3D printing nozzle. The device comprises: a printing unit, which is equipped with one or more 3D printing nozzles, and each 3D printing nozzle is provided with a hole-shaped nozzle at one end facing downward; a shooting unit, which is used to capture the image of the hole-shaped nozzle; a motion unit, which is used to achieve relative three-dimensional movement of the printing unit and the shooting unit; and a control unit, which is used to generate a control signal. The method comprises: moving the hole-shaped nozzle into the shooting field of view of the shooting unit by the motion unit; performing image automatic focusing on the hole-shaped nozzle by the shooting unit; collecting the image of the hole-shaped nozzle by the shooting unit and sending it to the control unit for image recognition; reading the actual coordinates of the hole-shaped nozzle by the control unit, and calculating the deviation value between the actual coordinates and the preset coordinates; in response to the control signal generated by the control unit based on the deviation value, driving the motion unit to correct the three-dimensional spatial position information of the hole-shaped nozzle.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printing, and in particular to a method and device for automatically correcting the position of a 3D printing nozzle. Background Art

[0002] 3D printing technology, also known as additive manufacturing technology, has developed into a key technology in the field of rapid prototyping. It allows the construction of three-dimensional solid objects by adding materials layer by layer. Among the many 3D printing technologies, biological 3D printing technology is particularly eye-catching. This technology uses specific 3D printing principles to construct biological materials (such as materials containing living cells) according to a predetermined three-dimensional structure, providing new possibilities for tissue engineering and regenerative medicine.

[0003] Bio3D printing is a technology that uses the principle of 3D printing to construct biological materials (such as biomaterials or cells) into a predetermined three-dimensional structure. Among the various bio3D printing technologies, extrusion bio3D printing technology is more widely used because of its advantages such as a wide range of material applications and high efficiency in building three-dimensional structures. Extrusion bio3D printing technology can use sterile disposable syringes and nozzles to control the extrusion of biomaterials. However, due to the assembly accuracy errors of the nozzle and the syringe, as well as the deformation and processing errors of the nozzle itself, the actual coordinate position of the nozzle tip in the printer is difficult to maintain consistency, which directly affects the quality and consistency of the printing effect. Especially in multi-nozzle printing systems, the coordinates of the nozzle tip need to be manually corrected multiple times before each print. This process is time-consuming and the user experience is poor, which seriously restricts the printing efficiency and the potential for large-scale application.

[0004] In the prior art, the identification of the nozzle position mainly relies on various sensors, including mechanical limit switches, optical sensors, laser sensors, inductive sensors and image recognition technology. For example, CN104786505A discloses a nozzle position calibration device, system and 3D printing device for a 3D printing device. The nozzle position calibration device of the 3D printing device includes: a height adjustment component and a horizontal calibration component; the height adjustment component and the horizontal calibration component are both arranged in a housing; the height adjustment component is used to connect with the calibration processor to transmit the pressure signal applied by the print nozzle on the height adjustment component in the vertical height direction to the calibration processor; the horizontal calibration component is used to connect with the calibration processor to transmit the position image of the print nozzle in the horizontal direction to the calibration processor. For another example, CN105662648A discloses a bioprinter and a calibration method thereof. The bio-printer provided by the invention includes a control device, a first detection device and a second detection device, wherein the first detection device can send a first signal to the control device when the injection device moves to a first position along the Z-axis direction so that the control device calibrates a preset value of the length of the injection device, and the second detection device can send a second signal to the control device when it moves to a second position along the Z-axis direction so that the control device calibrates a preset value of the height of the initial attachment surface of the printing material.

[0005] These technologies have some obvious limitations in practical applications. For example, contact sensors need to be sterilized before use, which not only increases the complexity of operation, but also may pose a potential risk to the sterility of the nozzle. Although non-contact sensors avoid direct contact, they often have the problem of insufficient recognition accuracy and are difficult to meet application scenarios with high precision requirements, especially for variable diameter nozzles, such as conical nozzles. The existing technology is difficult to achieve satisfactory results. Image recognition technology, as a non-contact recognition method, can theoretically provide high-precision nozzle position recognition. However, when traditional image recognition systems acquire three-dimensional information of 3D objects, they usually require at least two cameras to work together, which not only increases the complexity and cost of the system, but also increases the difficulty of calibration and maintenance. In view of these shortcomings of the prior art, the art is in urgent need of an improved method and device for automatic position correction of 3D printing nozzles.

[0006] In addition, on the one hand, there are differences in understanding among those skilled in the art; on the other hand, the applicant studied a large number of documents and patents when making the present invention, but due to space limitations, not all details and contents are listed in detail. However, this does not mean that the present invention does not have the characteristics of these prior arts. On the contrary, the present invention already has all the characteristics of the prior art, and the applicant reserves the right to add relevant prior art to the background technology. Summary of the invention

[0007] In view of the deficiencies of the prior art, the present invention provides a method and device for automatically correcting the position of a 3D printing nozzle to solve at least part of the above-mentioned technical problems.

[0008] The present invention discloses an automatic position correction device for a 3D printing nozzle, which is used for automatically correcting the position of a 3D printing nozzle of an extrusion-type biological 3D printing device, and comprises: a printing unit, which is equipped with one or more 3D printing nozzles, and each 3D printing nozzle is provided with a hole-shaped nozzle at one end facing downward; a shooting unit, which is equipped with a correction camera with a fixed position and shooting angle, and the correction camera is configured to shoot upward to capture an image of the hole-shaped nozzle; a motion unit, which is used to realize relative three-dimensional motion between the printing unit and the shooting unit; and a control unit, which is used to generate a control signal for adjusting the operating parameters of the printing unit, the shooting unit and / or the motion unit.

[0009] Preferably, the control unit is configured to: obtain the coordinate value of the hole-shaped nozzle in the Z direction by focusing, and then obtain the coordinate value of the hole-shaped nozzle in the X and Y directions by image recognition, so as to determine the actual coordinates of the hole-shaped nozzle by combining the coordinate values ​​of the hole-shaped nozzle in the X, Y and Z directions, and correct the three-dimensional spatial position information of the hole-shaped nozzle by calculating the deviation value between the actual coordinates and the preset coordinates. Specifically, in different stages in which the motion unit drives at least one 3D printing nozzle of the printing unit to move, the control unit can drive the shooting unit to respectively obtain the first image, the second image and the third image of the hole-shaped nozzle set on the 3D printing nozzle, so as to select a correction image and determine the actual coordinates of the hole-shaped nozzle according to the correction image and the position where the correction image is obtained.

[0010] The correction device of the present invention is particularly suitable for extrusion-type biological 3D printing equipment, which is an advanced manufacturing process for constructing three-dimensional structures of biological materials using 3D printing technology. Extrusion-type biological 3D printing technology has been widely used in the field of biomanufacturing due to its wide material applicability and high construction efficiency. Compared with traditional 3D printing equipment, extrusion-type biological 3D printing equipment has unique operating environment and material processing requirements. It usually uses a sterile disposable syringe and nozzle to accurately control the extrusion of materials containing living cells or other biological molecules to achieve the biomimetic construction of biological tissues. Due to the particularity of biological materials, extrusion-type biological 3D printing has extremely high requirements for the accuracy and cleanliness of the nozzle during the printing process. This leads to the need to frequently replace the 3D printing nozzle during the printing process to maintain the sterility of the nozzle and avoid cross contamination. After each nozzle is replaced, accurate position correction is required to ensure the continuity of the printing process and the accuracy of the printed structure. However, existing correction methods mostly rely on manual adjustment or simple mechanical limit, which are not only time-consuming and labor-intensive, but also difficult to achieve the micron-level accuracy required for biological 3D printing.

[0011] The automatic position correction device of the 3D printing nozzle of the present invention realizes the precise correction of the position of the hole-shaped nozzle of the 3D printing nozzle by integrating the printing unit, the shooting unit, the motion unit and the control unit. The hole-shaped nozzle on the printing unit is responsible for the extrusion of the material, which directly affects the printing quality. The correction camera of the shooting unit captures the nozzle image from below to provide the necessary visual information for position correction. The motion unit realizes the precise positioning of the nozzle through the driving mechanism in at least three directions, while the control unit is responsible for coordinating the operation of each unit and determining the actual coordinates of the nozzle by acquiring images at different stages. This process not only improves the automation level of the nozzle position correction, but also significantly improves the efficiency and accuracy of the correction by reducing manual intervention. In addition, the calculation and adjustment mechanism of the control unit ensures that the slight deviation of the nozzle position is corrected in time, thereby solving the time-consuming and error problems caused by manual correction in the prior art, and improving the repeatability and reliability of 3D printing.

[0012] The present invention innovatively realizes the position correction of three-dimensional space by only using a correction camera with a fixed position and shooting angle. In the automatic correction device for the position of the 3D printing nozzle of the present invention, a single correction camera is used as the core component of the shooting unit, which realizes a major breakthrough and innovation in technology. First, compared with the traditional multi-camera system, the single camera significantly simplifies the system structure, reduces the overall cost, and reduces the potential failure points, thereby improving the reliability of the system and the convenience of maintenance. Secondly, through the collaborative work of the high-precision 3D motion platform and the single camera, the present invention cleverly solves the limitation that the traditional single camera cannot obtain depth information, and uses the position information recording during the Z-axis movement, combined with the accurate clarity judgment algorithm, to achieve high-precision capture of depth information, which is crucial for Z-axis correction. In addition, the single correction camera solution of the present invention optimizes the correction process, and by accurately recording the position information of the Z-axis during the autofocus process, it not only improves the efficiency of correction, but also ensures the accuracy of image focusing. This method of obtaining depth information does not rely on the analysis of the image itself, but is based on the accuracy of mechanical movement and the accuracy of electronic control, thereby breaking through the limitations of traditional technology. At the same time, the solution of the present invention reduces the number of cameras, reduces system energy consumption and data processing requirements, and improves the correction speed. In fields such as biological 3D printing that have special requirements for sterility, the single camera system reduces the possibility of contact between the nozzle and the sensor, helps to maintain the sterility of the nozzle and avoids the risk of contamination that may be caused by contact sensors. In addition, the configuration of a single camera also makes it easier for the system to adapt to nozzles of different sizes and shapes, as well as different printing environments and requirements, enhancing the versatility and flexibility of the system.

[0013] According to a preferred embodiment, the motion unit responds to the control signal generated by the control unit based on the first target position, and drives the 3D printing nozzle to move in one or more of the three directions of X, Y, and Z, so that the hole-shaped nozzle can enter the shooting field of view of the shooting unit, wherein the shooting unit can capture the first image of the hole-shaped nozzle entering its shooting field of view and send it to the control unit.

[0014] The motion unit responds to the command of the control unit and accurately drives the 3D printing nozzle to move in the three directions of X, Y, and Z to ensure that the hole-shaped nozzle can enter the field of view of the shooting unit. This arrangement enables the control unit to flexibly adjust the position of the 3D printing nozzle to adapt to nozzles of different sizes and shapes, while improving the flexibility and adaptability of the correction process. By collecting the first image, the control unit can preliminarily determine whether the nozzle is correctly positioned, laying the foundation for subsequent autofocus and precise correction. This improvement solves the problem of inaccurate correction caused by field of view limitation in the prior art, and also reduces the errors that may be introduced due to manual adjustment. The correction process of the present invention only needs to ensure that the hole-shaped nozzle enters the shooting field of view of the shooting unit. It does not require the motion unit to accurately move the hole-shaped nozzle to the specified position, nor does it require the center of the hole-shaped nozzle to be on the same vertical line as the center of the correction camera. Compared with the traditional correction method, it is more flexible and simple, wherein the vertical line refers to a straight line perpendicular to the printing plane.

[0015] According to a preferred embodiment, a control unit that receives a first image of the hole-shaped nozzle is capable of performing a preliminary focusing operation, driving a motion unit to drive the 3D printing nozzle to move in the Z direction, so that the hole-shaped nozzle moves in the Z direction from the highest out-of-focus position of the image to the lowest clear position of the image, wherein, driven by the motion unit, each time the hole-shaped nozzle moves a first distance, the shooting unit captures a second image of the hole-shaped nozzle, and simultaneously records the spatial coordinates of the hole-shaped nozzle when each second image is taken.

[0016] The control unit can perform a preliminary focusing operation by driving the motion unit to fine-tune the position of the 3D printing nozzle in the Z direction to obtain continuous images from a defocused state to a clear state. This process uses the continuous change of the image to evaluate the focus and improve the accuracy of the focus. By recording the spatial coordinates of each image, the control unit can track the precise position of the nozzle in the Z direction, providing the necessary data support for subsequent fine focusing. This method effectively solves the problem of inaccurate focusing in the prior art, especially the positioning accuracy in the Z-axis direction, and provides a guarantee for achieving higher quality 3D printing. The correction camera of the shooting unit can fix the shooting parameters after initialization, and during the focusing operation, the focus can be achieved by only moving the hole-shaped nozzle, thereby realizing the correction operation of the 3D printing nozzle position using a correction camera with a fixed position, fixed shooting angle, and fixed shooting parameters, solving the defect that the traditional correction method needs to be re-calibrated once the position or parameters of the correction camera change.

[0017] According to a preferred embodiment, the control unit can use an image processing algorithm to evaluate the clarity of each second image collected by the preliminary focus to find the clearest second image, and can determine the second target position according to the spatial coordinates of the hole-shaped nozzle corresponding to the clearest second image, so as to move the hole-shaped nozzle to the second target position, wherein the second target position is the position determined by adding a preset value to the coordinate value of the spatial coordinate of the hole-shaped nozzle corresponding to the clearest second image in the Z direction. Preferably, the preset value can be set to 500 μm.

[0018] The control unit uses an image processing algorithm to evaluate the clarity of the second image, find the clearest image, and determine the second target position accordingly. This setting allows the control unit to accurately identify the optimal imaging state of the nozzle and make fine adjustments accordingly to achieve finer focus. By adding a preset value in the Z direction to set the second target position, the control unit can ensure that the nozzle starts from a position slightly higher than the clearest point when performing fine focusing, thereby avoiding loss of focus due to slight movements. This improvement significantly improves the accuracy and efficiency of focusing, and solves the print quality problem caused by inaccurate focusing in the prior art.

[0019] According to a preferred embodiment, the control unit is capable of performing a fine focusing operation on the hole-shaped nozzle that has moved to the second target position, driving the motion unit to drive the 3D printing nozzle to move in the Z direction, so that the hole-shaped nozzle moves from the second target position from top to bottom, wherein, driven by the motion unit, each time the hole-shaped nozzle moves a second distance, the shooting unit captures a third image of the hole-shaped nozzle, and simultaneously records the spatial coordinates of the hole-shaped nozzle when each third image is taken, and the second distance is smaller than the first distance, and much smaller than the first distance.

[0020] The control unit is able to perform fine focusing operations, moving the nozzle with smaller steps to capture higher-definition images. This setting enables the control unit to determine the exact position of the nozzle with higher accuracy, because smaller moving steps mean higher resolution and finer adjustment capabilities. By evaluating these high-definition images, the control unit is able to identify the clearest third image, thereby ensuring accurate positioning of the nozzle in the Z direction. This improvement solves the problem of inaccurate positioning caused by excessive step length in the prior art, and provides technical guarantee for achieving high-precision 3D printing.

[0021] According to a preferred embodiment, the control unit can use an image processing algorithm to evaluate the clarity of each third image captured by fine focus, find the clearest third image and use it as a correction image, wherein the control unit can make the hole-shaped nozzle stationary at the spatial position when the correction image is obtained, and extract the coordinate value in the Z direction corresponding to the spatial position.

[0022] The control unit uses an image processing algorithm to evaluate the clarity of the third image and selects the clearest image as the correction image. This setting ensures that the control unit can identify the optimal imaging of the nozzle end, thereby providing high-quality visual data for subsequent contour recognition and coordinate calculation. By keeping the hole-shaped nozzle stationary in this optimal imaging position, the control unit can stably acquire and process the image, avoiding image blur or distortion that may be introduced by the movement of the 3D printing nozzle. This improvement significantly improves the accuracy of image recognition and lays the foundation for accurate hole-shaped nozzle position correction.

[0023] According to a preferred embodiment, the control unit is capable of identifying the correction image to extract the outline of the hole-shaped nozzle and calculate the position information of the center point of the nozzle, wherein the control unit is capable of converting the position information represented by pixel coordinates into actual physical coordinates to obtain the coordinate values ​​of the hole-shaped nozzle in the X and Y directions.

[0024] The control unit can identify the calibration image, extract the nozzle outline, calculate the center point position information, and then convert the pixel coordinates into physical coordinates. This setting enables the control unit to accurately determine the position of the nozzle in the X and Y directions, providing the necessary two-dimensional coordinate data for accurate correction of the nozzle position in three-dimensional space. Through this conversion, the control unit can associate the image data with the actual physical size, thereby solving the calibration error problem caused by the inconsistency between image recognition and actual object size in the prior art.

[0025] According to a preferred embodiment, the control unit is capable of comparing the actual coordinates of the hole-shaped nozzle determined based on the coordinate values ​​of the hole-shaped nozzle in the X, Y, and Z directions with the preset coordinates of the hole-shaped nozzle in three-dimensional space to calculate a deviation value, wherein the preset coordinates of the hole-shaped nozzle in three-dimensional space are machine preset values ​​pre-set based on an ideal hole-shaped nozzle.

[0026] The control unit determines the actual coordinates based on the coordinate values ​​of the hole-shaped nozzle in the X, Y, and Z directions, and compares them with the preset coordinates to calculate the deviation value. This setting enables the control unit to accurately evaluate the accuracy of the hole-shaped nozzle position and make adjustments based on the deviation value. Through the pre-set machine preset values, the control unit can standardize the nozzle position to ensure consistency and repeatability of each print.

[0027] According to a preferred embodiment, when the printing unit is configured with multiple 3D printing heads and multiple 3D printing heads need to be automatically calibrated, the control unit can correct the positions of the 3D printing heads to be calibrated one by one until the positions of all 3D printing heads to be calibrated are corrected.

[0028] When the printing unit is equipped with multiple 3D printing nozzles, the control unit can correct the position of each nozzle one by one. This setting significantly improves the correction efficiency of the multi-nozzle 3D printing system and ensures that the positions of all nozzles can be accurately corrected. Through the automated one-by-one correction process, the device can avoid the tediousness of manual correction and possible omissions, ensuring the efficiency of the printing job and the consistency of the printing quality. This improvement solves the problem of difficult and time-consuming correction of the multi-nozzle system in the prior art.

[0029] The present invention also discloses a method for automatically correcting the position of a 3D printing nozzle, which comprises:

[0030] The hole-shaped nozzle of the 3D printing nozzle is moved into the shooting field of view of the shooting unit by the motion unit;

[0031] Automatically focusing the image of the hole-shaped nozzle using a photographing unit;

[0032] Using the photographing unit to collect an image of the hole-shaped nozzle and sending it to the control unit so that the control unit can recognize the image;

[0033] The control unit is used to read the actual coordinates of the hole-shaped nozzle in the three-dimensional space, and calculate the deviation between the actual coordinates and the preset coordinates of the hole-shaped nozzle in the three-dimensional space;

[0034] In response to a control signal generated by the control unit based on the deviation value, the motion unit is driven to correct the three-dimensional spatial position information of the hole-shaped nozzle. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a hardware connection diagram of a correction device of a preferred embodiment provided by the present invention;

[0036] Figure 2 It is a structural schematic diagram of a correction device according to a preferred embodiment of the present invention;

[0037] Figure 3 is a schematic diagram of a first image acquired by a shooting unit according to a preferred embodiment of the present invention;

[0038] Figure 4 is a schematic diagram of a third image acquired by a shooting unit in a preferred embodiment provided by the present invention;

[0039] Figure 5 It is a schematic diagram of a control unit identifying a correction image acquired by a shooting unit according to a preferred embodiment of the present invention.

[0040] Reference numerals list

[0041] 100: printing unit; 110: 3D printing nozzle; 120: hole-shaped nozzle; 200: shooting unit; 300: motion unit; 400: control unit. DETAILED DESCRIPTION

[0042] The following is a detailed description with reference to the accompanying drawings.

[0043] The present invention discloses an automatic position correction device for a 3D printing nozzle 110, which comprises: a printing unit 100, which is equipped with one or more 3D printing nozzles 110, and a hole-shaped nozzle 120 may be provided at one end of the 3D printing nozzle 110 facing downward; a shooting unit 200, which may be configured as a correction camera for shooting upward; a motion unit 300, which is used to realize the relative three-dimensional motion of the printing unit 100 and / or the shooting unit 200; and a control unit 400, which is used to generate a control signal for adjusting the operating parameters of the printing unit 100, the shooting unit 200 and / or the motion unit 300. Optionally, the above and the below may refer to the vertically upward and vertically downward directions, or may refer to the directions having vertically upward and vertically downward component vectors. Preferably, in the present invention, the above and the below are the vertically upward and vertically downward directions. Figure 1 is a hardware connection diagram of the correction device of the present invention, Figure 2 It is a schematic structural diagram of the correction device of the present invention.

[0044] Preferably, the printing unit 100 may include a support structure for detachably fixing the 3D printing nozzle 110, so that the printing unit 100 can flexibly replace 3D printing nozzles 110 of different specifications or types according to printing requirements and / or printing materials, wherein the support structure can be connected to the motion unit 300, so that the printing unit 100 can adjust its position in space with the movement of the motion unit 300. Furthermore, the support structure can be made of high-strength materials to ensure stability during a long printing process and reduce errors caused by mechanical vibration or thermal deformation.

[0045] Preferably, the setting of the hole-shaped nozzle 120 of the 3D printing nozzle 110 directly affects the accuracy and quality of printing. Therefore, the hole-shaped nozzle 120 of the 3D printing nozzle 110 of the present invention takes into account the rheological properties of the printing material when designing to ensure that the material can be uniformly and continuously extruded from the hole-shaped nozzle 120. Further, the printing unit 100 of the present invention can be configured with a plurality of 3D printing nozzles 110 with hole-shaped nozzles 120 of different diameters (i.e., inner diameters) to adapt to printing materials of different diameters, thereby achieving printing accuracy from micron level to millimeter level. Preferably, the material selection of the hole-shaped nozzle 120 takes into account chemical stability and wear resistance to resist corrosion or wear that may be caused by the printing material. Preferably, the structural shape of the hole-shaped nozzle 120 is not limited, and can be a combination of one or more of a steel needle type dispensing needle (tubular or cylindrical), a TT type dispensing needle (conical), a Musashi head, a coaxial nozzle, and a homemade hole-shaped nozzle. Further, the hole-shaped nozzles 120 of different structural shapes may also have different diameters. For example, the diameter of the TT-type dispensing needle may include 10 G, 11 G, 13 G, 14 G, 16 G, 18 G, 20 G, 21 G, 22 G, 23 G, 24 G, 27 G, 30 G, etc., and the diameter of the steel needle-type dispensing needle may include 14 G, 15 G, 16 G, 17 G, 18 G, 19 G, 20 G, 21 G, 22 G, 23 G, 24 G, 25 G, 26 G, 27 G, 30 G, 32 G, etc. Preferably, the inner diameter of the hole-shaped nozzle 120 is generally 0.01-3 mm. Preferably, the hole-shaped nozzle 120 is usually arranged in a manner that its end is vertically downward.

[0046] Preferably, the main function of the shooting unit 200 is to capture the image of the hole-shaped nozzle 120 from below the 3D printing nozzle 110, and provide necessary visual information for subsequent image processing and position correction of the 3D printing nozzle 110. Further, when the shooting unit 200 is configured as a correction camera, it is designed to shoot upward to clearly capture the image of the hole-shaped nozzle 120. Preferably, the selection and configuration of the correction camera take into account a number of key factors, including resolution, dynamic range, sensitivity, and performance under different lighting conditions. In order to achieve high-resolution image capture, the camera is equipped with a high-pixel photosensitive element to ensure that even tiny details of the hole-shaped nozzle 120 can be accurately recorded.

[0047] In order to maintain the sterility of the hole-shaped nozzle 120, traditional contact sensors (such as mechanical limit switches) usually need to sterilize the surface of the sensor before use, which makes the operation troublesome and still has the possibility of causing contamination. For example, when a mechanical limit switch is used as a contact sensor, the main function of the mechanical limit switch (commonly referred to as a limit switch) is to serve as a mechanical switch for position control, which is used to detect whether an object (here, the hole-shaped nozzle 120) has reached a specific position. When the object contacts the limit switch, the state of the switch will change (for example, from normally open to normally closed), thereby triggering a circuit or control signal to achieve the restriction of mechanical movement or position detection. Therefore, if a mechanical limit switch is used as a sensor to detect the position of the hole-shaped nozzle 120, the hole-shaped nozzle 120 will inevitably contact the surface of the sensor, thereby increasing the risk of contamination. Preferably, the shooting unit 200 of the present invention that uses image recognition to detect the position of the hole-shaped nozzle 120 can completely avoid the influence of traditional contact sensors on the sterility of the hole-shaped nozzle 120. It does not require additional sterilization operations, simplifies the operation process, and is particularly suitable for the strict requirements for a sterile environment in the biological 3D printing process. It also avoids mechanical wear and contact damage, thereby improving the durability of the system.

[0048] Preferably, compared with contact sensors, non-contact sensors can simplify operation and reduce the risk of contamination, but most traditional non-contact sensors have low recognition accuracy (i.e., they cannot accurately detect objects around 100 microns), especially the problem of being unable to accurately identify nozzles with variable diameters (such as conical nozzles).

[0049] Based on this, the shooting unit 200 of the present invention can send the collected image to the control unit 400 integrated with the image recognition algorithm to achieve high-precision recognition of the top position of the hole-shaped nozzle 120, and can optimize the contrast and brightness of the image, improve the clarity and recognizability of the image, wherein the image recognition algorithm can be based on direct calculation of the image, or can be trained by AI. Further preferably, the image recognition algorithm adopts AI training, wherein the AI ​​training model used by the control unit 400 of the present invention can be a YOLOv8 model, an EfficientNet / EfficientDet model, a Faster R-CNN model, an SSD model, a CenterNet model or a RetinaNet model, etc., and the model training data contains image data of multiple different types of hole-shaped nozzles 120, so that the trained AI model can accurately recognize common hole-shaped nozzles 120. Preferably, the YOLOv8 model is an end-to-end real-time target detection system that can complete the task of object positioning and classification in a single neural network. Starting from the initial YOLOv1 model, each generation has been continuously improving the algorithm structure, optimizing the training strategy, and improving the detection speed and accuracy. The YOLOv8 model inherits the advantages of the previous version and is optimized on this basis. The YOLOv8 model adopts a more unified framework to handle different tasks, making the model more flexible, and it can use the advanced convolutional neural network architecture to extract features more effectively. Preferably, the EfficientDet model adopts the design concept of the EfficientNet model to improve the model performance by balancing the growth of width, depth and resolution while maintaining a low amount of calculation. Preferably, the Faster R-CNN model adopts a two-stage approach, first using a region proposal network to generate candidate regions, and then classifying and regressing each candidate region. Since the accuracy of Faster R-CNN is generally high, it is very suitable for scenarios that require highly accurate 3D printing nozzle 110 position correction. Preferably, the SSD model completes the target detection task in a single forward propagation, and it directly predicts the target category and position on multiple fixed-size feature maps. The SSD model has a fast detection speed and is a good choice for a 3D printing nozzle 110 position correction device that requires real-time feedback. Preferably, the CenterNet model is a keypoint-based detection method that detects by predicting the center point of the target and estimating the size of the target around the center point. The advantage of the CenterNet model is that it can detect targets quickly and performs well in dense object detection. Preferably, the RetinaNet model solves the problem of foreground-background sample imbalance by introducing focal loss, thereby improving the accuracy of small target detection.Preferably, the recognition and correction accuracy of the present invention can reach 10 microns in the X and Y directions and 1 micron in the Z direction to ensure printing accuracy. Traditional mechanical limit switches and optical sensors cannot achieve this accuracy, and the present invention breaks through the limitations of these technologies.

[0050] Preferably, the image recognition algorithm of the present invention can adapt to nozzles of various shapes, including but not limited to cylindrical and conical nozzles, to ensure accurate recognition and correction regardless of the shape of the nozzle. This adaptability enables the present invention to have a wider range of applications and meet the needs of different biological 3D printing applications.

[0051] Preferably, compared to the traditional image recognition method which requires at least two cameras to obtain the three-dimensional information of the 3D object, the shooting unit 200 of the present invention can be configured with only one calibration camera to achieve high-precision nozzle position recognition. Such a setting not only reduces the hardware cost, simplifies the system structure, improves the reliability and usability of the device, but also reduces the complexity of calibration and maintenance.

[0052] Preferably, the shooting unit 200 may have automatic exposure and automatic white balance functions to automatically adjust the exposure level and color balance of the image to ensure that high-quality images can be obtained in different lighting environments.

[0053] Preferably, the motion unit 300 of the present invention can use one or more combinations of high-precision servo motors, stepper motors, AC motors or DC motors as a driving source to achieve accurate positioning of the 3D printing nozzle 110 in the three directions of X, Y, and Z, wherein these motors have high-resolution encoders that can provide accurate position feedback to ensure that the error of the nozzle when it moves to a predetermined position is controlled at the micron level. Furthermore, the selection of the motor also takes into account its torque and speed characteristics to meet the requirements of fast response and large load.

[0054] Preferably, the motion unit 300 used to realize the relative three-dimensional motion of the printing unit 100 and the shooting unit 200 can usually drive the printing unit 100 to complete the movement in three-dimensional space, wherein the mechanical structure design of the motion unit 300 can adopt precise guide rails and bearings to ensure the stability and repeatability of the 3D printing nozzle 110 of the printing unit 100 during the movement. Furthermore, the material selection of the guide rails and bearings takes into account the wear resistance and low friction characteristics to reduce the resistance and wear during the movement. In addition, the guide rails can be designed with a preload mechanism to improve the rigidity and stability of the motion unit 300.

[0055] Preferably, the motion unit 300 may acquire actual position information based on sensor acquisition and / or calculation and deduction of the motor movement distance, and may send the acquired position information to the control unit 400 .

[0056] Preferably, the core of the control unit 400 responsible for coordinating and managing the operations of the printing unit 100, the photographing unit 200 and the motion unit 300 is a high-performance microprocessor or microcontroller, which has strong computing power and can run complex control algorithms and process high-speed data streams. Further, the selection of the microprocessor takes into account processing speed, memory capacity and input / output capabilities to meet the needs of real-time control. The control unit 400 also includes a high-speed data storage device, such as a solid state drive (SSD) or an electronically erasable read-only memory (EEPROM), for storing system parameters, calibration data and log information.

[0057] Preferably, the control unit 400 may adopt a modular and layered architecture to improve the scalability and maintainability of the system. Further, the modular design allows the functional modules of the control unit 400, such as the motion control module, the image processing module, the user interface module, and the communication module, to be flexibly configured according to different application requirements. Further, the layered architecture divides the system functions into different levels, such as the hardware abstraction layer, the driver layer, the application layer, and the user interface layer, to achieve clear functional division and efficient task scheduling.

[0058] Preferably, in order to achieve precise motion control, the control unit 400 can integrate advanced motion control algorithms, such as PID control, feedforward control, and adaptive control. These algorithms can accurately calculate the drive signal of the motion unit 300 to achieve precise adjustment of the print head position. Furthermore, the control unit 400 also has real-time monitoring and diagnosis functions, and can monitor the state of the motion unit 300, such as speed, acceleration, and load, to ensure the stability and safety of the motion process.

[0059] Preferably, based on the control unit 400 regulating the printing unit 100, the shooting unit 200 and / or the motion unit 300, the correction device of the present invention can realize automatic correction of the position of the 3D printing nozzle 110, wherein the correction method may include:

[0060] S1. The hole-shaped nozzle 120 of the 3D printing nozzle 110 of the printing unit 100 is moved into the shooting field of view of the shooting unit 200 by the motion unit 300;

[0061] S2. Automatically focusing the image of the hole-shaped nozzle 120 using the shooting unit 200;

[0062] S3. The image of the hole-shaped nozzle 120 is collected by the shooting unit 200 and sent to the control unit 400, so as to recognize the image by the control unit 400;

[0063] S4. Using the control unit 400 to read the actual coordinates of the hole-shaped nozzle 120 in the three-dimensional space, and calculate the deviation between the actual coordinates of the hole-shaped nozzle 120 in the three-dimensional space;

[0064] S5 . In response to the control signal generated by the control unit 400 based on the deviation value, the motion unit 300 is driven to correct the three-dimensional spatial position information of the hole-shaped nozzle 120 .

[0065] Preferably, the 3D printing nozzle 110 of the printing unit 100 may be initially set before executing step S1 to ensure the assembly accuracy of the 3D printing nozzle 110 and the hole-shaped nozzle 120. In addition, the camera of the shooting unit 200 needs to be calibrated to ensure that the image it captures accurately corresponds to the position of the actual object.

[0066] Preferably, in step S1, the control unit 400 can drive the motion unit 300 to drive the 3D printing nozzle 110 to move in the three directions of X, Y, and Z according to the approximate positional relationship between the printing unit 100 and the shooting unit 200, so that a hole-shaped nozzle 120 of the 3D printing nozzle 110 can enter the shooting field of view of the shooting unit 200, wherein the image collected by the shooting unit 200 in this step is Figure 3 The first image shown is only used to determine whether the hole-shaped nozzle 120 enters the shooting field of view of the shooting unit 200. In other words, in this step, there is no requirement for the clarity of the first image captured by the shooting unit 200. Further, the first image acquired by the shooting unit 200 can be sent to the control unit 400 so that the control unit 400 can perform the above-mentioned determination operation.

[0067] Preferably, before executing step S1, the control unit 400 can obtain the relative position coordinates (hereinafter referred to as spatial coordinates) of the 3D printing nozzle 110, the hole-shaped nozzle 120 in the ideal installation position on the 3D printing nozzle 110, and the shooting unit 200 in three-dimensional space by sensor monitoring and / or manual input, and can calculate the optimal movement path of the hole-shaped nozzle 120 to the first target position based on the known coordinate information, wherein the control unit 400 can use algorithms such as trapezoidal control algorithm or fuzzy logic control algorithm to optimize the movement path of the nozzle to reduce the movement time and energy consumption. This is set because the hole-shaped nozzle 120 usually has an installation error (generally not more than 3 mm) during installation. Therefore, the specific position of the newly installed hole-shaped nozzle 120 in the shooting field of view of the shooting unit 200 may not be fixed each time, resulting in the hole-shaped nozzle 120 that has completed the movement deviating from the first target position even if an accurate movement plan is calculated. Based on this, step S1 of the present invention only determines whether the hole-shaped nozzle 120 enters the shooting field of view of the shooting unit 200 to achieve rapid coarse adjustment, thereby improving the accuracy and efficiency of the correction.

[0068] Preferably, when the shooting unit 200 is configured as a calibration camera with a suitable shooting field of view, the hole-shaped nozzle 120 can basically enter its shooting field of view by moving in three-dimensional space. Preferably, if the control unit 400 cannot recognize the first image after the hole-shaped nozzle 120 enters the shooting field of view of the shooting unit 200, the secondary recognition should be restarted. Furthermore, if the recognition fails for multiple consecutive times, a training set of such hole-shaped nozzles 120 can be added to the control unit 400 to improve the recognition ability of the AI ​​model in the control unit 400 through neural network learning. Preferably, compared with traditional image calculation and processing methods, the speed of recognition using AI is extremely fast (AI recognition speed is in milliseconds, and image calculation is about in seconds), and after training, many types of nozzles can be recognized with high accuracy.

[0069] Preferably, when the control unit 400 determines that the porous nozzle 120 enters the shooting field of view of the shooting unit 200 based on the first image acquired by the shooting unit 200, step S2 can be executed, wherein in step S2, the control unit 400 can send a focus instruction to the shooting unit 200 to trigger the autofocus process.

[0070] Preferably, during the auto-focusing process, the following sub-steps may be performed:

[0071] S2.1. Preliminary focusing: The motion unit 300 is used to drive the 3D printing nozzle 110 to move in the Z direction (i.e., the vertical direction), so that the hole-shaped nozzle 120 can move from the highest out-of-focus point of the image to the lowest clear point of the image in the Z direction, that is, complete the top-down movement. Driven by the motion unit 300, the shooting unit 200 can capture a second image of the hole-shaped nozzle 120 every time the hole-shaped nozzle 120 moves 1 mm, and simultaneously record the spatial coordinates of the hole-shaped nozzle 120 when each second image is taken, especially the coordinate value in the Z direction.

[0072] S2.2. Use an image processing algorithm to evaluate the clarity of each second image acquired by the preliminary focusing, and find the clearest second image.

[0073] S2.3. Fine focus: Use the motion unit 300 to drive the 3D printing nozzle 110 to move, so as to move the hole-shaped nozzle 120 to the second target position associated with the spatial coordinates determined in step S2.2, and complete the top-down movement from the second target position, wherein the second target position can be a position determined by increasing the coordinate value of the spatial coordinate determined in step S2.2 in the Z direction by a preset value. Preferably, the increased preset value can be set to 500 μm, so that the second target position is 500 μm higher in height than the position corresponding to the spatial coordinate determined in step S2.2 in the three-dimensional space. Preferably, when the hole-shaped nozzle 120 moves from the second target position from top to bottom, it can move a total distance of 1 mm in the Z direction, wherein, driven by the motion unit 300, the shooting unit 200 can collect a picture of the hole-shaped nozzle 120 every time the hole-shaped nozzle 120 moves 1 μm. Figure 4 The third images shown are taken, and the spatial coordinates of the hole-shaped nozzle 120 when each third image is taken are recorded at the same time, especially the coordinate values ​​in the Z direction.

[0074] S2.4. Use an image processing algorithm to evaluate the clarity of each third image acquired by fine focusing, and find the clearest third image.

[0075] Preferably, in step S2, the coordinate value in the Z direction can be obtained based on the measurement of the motor movement distance, that is, the motion unit 300 can know the origin coordinates in the Z direction after installation, and after the motor of the motion unit 300 controls the 3D printing nozzle 110 to move a known distance in the Z direction, the new coordinate value of the hole-shaped nozzle 120 of the 3D printing nozzle 110 in the Z direction can be calculated.

[0076] Preferably, the image processing algorithm may include but is not limited to the Laplace operator, the gradient descent algorithm or the frequency domain analysis method, which can accurately identify the high-frequency components in the image, thereby evaluating the clarity of the image. Further preferably, the image processing algorithm of the present invention may use the Laplace operator, which is mainly used for edge detection and clarity evaluation of the image. The Laplace operator can highlight the rapidly changing areas in the image, i.e., the edges, based on the intensity changes of the image, to help determine which areas in the image have the most obvious edge contrast, thereby evaluating the clarity of the image. Preferably, during the autofocus process, the control unit 400 can obtain a series of images at different focal lengths through the shooting unit 200, and then process each image using the Laplace operator to determine which image has the highest edge contrast by comparing the Laplace response or energy of each image, thereby selecting the clearest image and determining the spatial coordinates corresponding to the clearest image, especially the coordinate value in the Z direction.

[0077] Preferably, step S2 can obtain Figure 5 The clearest image of the hole-shaped nozzle 120 (hereinafter referred to as the correction image) is shown, and the hole-shaped nozzle 120 is kept stationary at the spatial position when this most corrected image is obtained, so as to provide a high-quality image by automatically adjusting the focal length, thereby being used for subsequent image processing and recognition, and improving the accuracy of correction.

[0078] Preferably, after obtaining the clearest image of the hole-shaped nozzle 120 (i.e., the corrected image) through step S2, step S3 can be performed, wherein, in step S3, the control unit 400 can perform AI contour recognition on the hole-shaped nozzle 120 to extract the contour of the hole-shaped nozzle 120 and calculate the position information of the center point of the nozzle (i.e., the end of the hole-shaped nozzle 120). Further, the position information can be expressed in pixel coordinates, and the control unit 400 can convert it into actual physical coordinates (i.e., spatial coordinates), wherein the corresponding proportional relationship between the pixel coordinates and the physical coordinates can be obtained by pre-calibration based on the shooting field of view of the shooting unit 200 and the actual object size. Preferably, through step S3, the coordinate values ​​of the center point of the nozzle in the X and Y directions can be accurately obtained to ensure the recognition and printing accuracy. Figure 5 The image processing information of the hole-shaped nozzle 120 after the recognition step is completed is shown, the black dotted box shows the contour recognition information, and the black dot shows the center point position of the nozzle.

[0079] Preferably, if the control unit 400 cannot perform AI recognition on the outline of the hole-shaped nozzle 120 in the clear image, the secondary recognition should be restarted. Furthermore, if the recognition fails for multiple consecutive times, a training set of such hole-shaped nozzles 120 can be added to the control unit 400 to improve the recognition ability of the AI ​​model in the control unit 400 through neural network learning.

[0080] Preferably, after obtaining the accurate physical coordinates of the center point of the nozzle in the X and Y directions through step S3, step S4 can be executed, wherein, in step S4, the control unit 400 can form the actual (three-dimensional) coordinates of the hole-shaped nozzle 120 according to the coordinate values ​​of the hole-shaped nozzle 120 in the Z direction obtained in step S2 and the coordinate values ​​of the hole-shaped nozzle 120 in the X and Y directions obtained in step S3, and can compare the actual coordinates with the preset coordinates of the hole-shaped nozzle 120 in the three-dimensional space to calculate the deviation value. Further, the deviation value includes position errors in the three directions of X, Y, and Z. Preferably, the preset coordinates of the hole-shaped nozzle 120 in the three-dimensional space are machine preset values ​​pre-set based on the ideal hole-shaped nozzle 120. Preferably, the control unit 400 can adjust the accuracy of the deviation value calculation according to different printing tasks and accuracy requirements, and can provide a basis for subsequent correction by accurately evaluating the position deviation of the hole-shaped nozzle 120.

[0081] Preferably, after obtaining the deviation value between the actual coordinates and the preset coordinates through step S4, step S5 can be executed, wherein, in step S5, the control unit 400 can correct the position of the hole-shaped nozzle 120 according to the calculated deviation value to ensure that the corrected hole-shaped nozzle 120 can reach the preset ideal position each time it moves, thereby improving printing accuracy.

[0082] Preferably, the deviation value calculated in step S4 reflects the error of the position of the hole-shaped nozzle 120 and is the basis for position correction. The control unit 400 can generate a corresponding control signal by analyzing the data of the deviation value, thereby guiding the motion unit 300 to make precise position adjustments. Preferably, after the motion unit 300 receives the control signal sent by the control unit 400, it will accurately adjust the position of the hole-shaped nozzle 120. This adjustment may involve movement in one or more of the three directions of X, Y, and Z to compensate for the deviation value. The motor of the motion unit 300 will drive the 3D printing nozzle 110 to drive the hole-shaped nozzle 120 to move to the corrected position along the specified direction according to the power provided by the control signal. Since the mechanical structure design of the motion unit 300 ensures sufficient rigidity and stability, the generation of additional errors is avoided during the adjustment process.

[0083] Preferably, while the position of the 3D printing nozzle 110 is adjusted, the control unit 400 will continue to monitor the entire calibration process to ensure that the operation of the motion unit 300 is in line with expectations. Further, the control unit 400 will receive feedback signals from the motion unit 300 in real time, which may include information such as the current position, speed, and acceleration of the 3D printing nozzle 110. Through this feedback information, the control unit 400 can adjust the control strategy in real time to deal with unexpected situations that may occur.

[0084] Preferably, when the printing unit 100 is equipped with a plurality of 3D printing heads 110 and the plurality of 3D printing heads 110 need to be automatically calibrated, the calibration method may further include:

[0085] S6. After automatically calibrating the position of any 3D printing nozzle 110, repeat steps S1 to S5 to correct the position of the 3D printing nozzle 110 to be calibrated one by one until the positions of all 3D printing nozzles 110 to be calibrated are corrected.

[0086] It should be noted that the above-mentioned specific embodiments are exemplary, and those skilled in the art can come up with various solutions inspired by the disclosure of the present invention, and these solutions also belong to the disclosure scope of the present invention and fall within the protection scope of the present invention. Those skilled in the art should understand that the present invention specification and its drawings are illustrative and do not constitute a limitation of the claims. The scope of protection of the present invention is defined by the claims and their equivalents. The present invention specification contains multiple inventive concepts, such as "preferably" or "according to a preferred embodiment", which means that the corresponding paragraph discloses an independent concept, and the applicant reserves the right to file a divisional application based on each inventive concept. Throughout the text, the features guided by "preferably" are only an optional method and should not be understood as a must-have setting. Therefore, the applicant reserves the right to abandon or delete the relevant preferred features at any time.

Claims

1. A 3D printing nozzle position automatic correction device, used for automatically correcting the position of a 3D printing nozzle (110) of an extrusion-type biological 3D printing device, characterized in that: It includes: A printing unit (100) is provided with one or more 3D printing nozzles (110), and each 3D printing nozzle (110) is provided with a hole-shaped nozzle (120) at one end facing downward; A shooting unit (200) is provided with a correction camera with a fixed position and shooting angle, the correction camera being configured to shoot upwards, and used to capture an image of the hole-shaped nozzle (120); A motion unit (300) for realizing relative three-dimensional motion of the printing unit (100) and the photographing unit (200); A control unit (400) is used to generate a control signal for adjusting operating parameters of a printing unit (100), a photographing unit (200) and / or a motion unit (300), wherein: The control unit (400) for determining the actual coordinates of the hole-shaped nozzle (120) by acquiring images at different stages is configured as follows: In different stages of movement of at least one of the 3D printing nozzles (110) of the printing unit (100) driven by the motion unit (300), the control unit (400) drives the photographing unit (200) to respectively acquire a first image for preliminarily determining whether the nozzle is correctly positioned, a second image for fine focusing, and a third image of the hole-shaped nozzle (120) provided on the 3D printing nozzle (110), so as to select a correction image and determine the actual coordinates of the hole-shaped nozzle (120) according to the correction image and the position at which the correction image is acquired. The coordinate value of the hole-shaped nozzle (120) in the Z direction is obtained by focusing, and the coordinate values ​​of the hole-shaped nozzle (120) in the X and Y directions are obtained by image recognition, so that the actual coordinates of the hole-shaped nozzle (120) are determined by combining the coordinate values ​​of the hole-shaped nozzle (120) in the X, Y and Z directions, and the three-dimensional spatial position information of the hole-shaped nozzle (120) is corrected by calculating the deviation value between the actual coordinates and the preset coordinates. The motion unit (300) drives the 3D printing nozzle (110) to move in one or more of the three directions of X, Y, and Z in response to a control signal generated by the control unit (400) based on the first target position, so that the hole-shaped nozzle (120) can enter the shooting field of view of the shooting unit (200), wherein the shooting unit (200) can capture a first image of the hole-shaped nozzle (120) entering its shooting field of view and send it to the control unit (400), The control unit (400) that receives the first image of the hole-shaped nozzle (120) is capable of performing a preliminary focusing operation, driving the motion unit (300) to drive the 3D printing nozzle (110) to move in the Z direction, so that the hole-shaped nozzle (120) moves in the Z direction from the highest out-of-focus position of the image to the lowest clear position of the image, wherein, under the drive of the motion unit (300), each time the hole-shaped nozzle (120) moves a first distance, the shooting unit (200) captures a second image of the hole-shaped nozzle (120) and simultaneously records the spatial coordinates of the hole-shaped nozzle (120) when each second image is shot. The control unit (400) is capable of using an image processing algorithm to evaluate the clarity of each second image acquired by preliminary focusing, so as to find the clearest second image, and is capable of determining a second target position according to the spatial coordinates of the hole-shaped nozzle (120) corresponding to the clearest second image, so as to move the hole-shaped nozzle (120) to the second target position, wherein the second target position is a position determined by adding a preset value to the coordinate value of the spatial coordinate of the hole-shaped nozzle (120) corresponding to the clearest second image in the Z direction, The control unit (400) is capable of performing a fine focusing operation on the hole-shaped nozzle (120) that has moved to the second target position, and driving the motion unit (300) to drive the 3D printing nozzle (110) to move in the Z direction, so that the hole-shaped nozzle (120) moves from the second target position from top to bottom, wherein, under the drive of the motion unit (300), each time the hole-shaped nozzle (120) moves a second distance, the shooting unit (200) captures a third image of the hole-shaped nozzle (120) and simultaneously records the spatial coordinates of the hole-shaped nozzle (120) when each third image is shot, the second distance being smaller than the first distance, The control unit (400) is capable of using an image processing algorithm to evaluate the clarity of each third image acquired by fine focusing, find the clearest third image and use it as a correction image, wherein the control unit (400) is capable of making the hole-shaped nozzle (120) stationary at the spatial position when the correction image is obtained, and extracting the coordinate value in the Z direction corresponding to the spatial position, The control unit (400) is capable of identifying the correction image to extract the contour of the hole-shaped nozzle (120) and calculate the position information of the center point of the nozzle, wherein the control unit (400) is capable of converting the position information represented by pixel coordinates into actual physical coordinates to obtain the coordinate values ​​of the hole-shaped nozzle (120) in the X and Y directions.

2. The calibration device according to claim 1, characterized in that: The control unit (400) is capable of comparing the actual coordinates of the hole-shaped nozzle (120) determined based on the coordinate values ​​of the hole-shaped nozzle (120) in the X, Y, and Z directions with the preset coordinates of the hole-shaped nozzle (120) in three-dimensional space, so as to calculate a deviation value, wherein the preset coordinates of the hole-shaped nozzle (120) in three-dimensional space are machine preset values ​​pre-set based on an ideal hole-shaped nozzle (120).

3. The calibration device according to claim 1, characterized in that: When the printing unit (100) is equipped with a plurality of the 3D printing heads (110) and the plurality of the 3D printing heads (110) need to be automatically calibrated, the control unit (400) can correct the positions of the 3D printing heads (110) to be calibrated one by one until the positions of all the 3D printing heads (110) to be calibrated are corrected.

4. A method for automatically correcting the position of a 3D printing nozzle using the automatic position correction device of any one of claims 1 to 3, characterized in that: It includes: The hole-shaped nozzle (120) of the 3D printing nozzle (110) is moved into the shooting field of view of the shooting unit (200) by means of the motion unit (300); Utilizing the photographing unit (200) to automatically focus the image of the hole-shaped nozzle (120); Using the photographing unit (200) to collect an image of the hole-shaped nozzle (120) and sending the image to the control unit (400), so that the control unit (400) can recognize the image; Using the control unit (400) to read the actual coordinates of the hole-shaped nozzle (120) in the three-dimensional space, and calculating the deviation value between the actual coordinates and the preset coordinates of the hole-shaped nozzle (120) in the three-dimensional space; In response to a control signal generated by a control unit (400) based on the deviation value, the motion unit (300) is driven to correct the three-dimensional spatial position information of the hole-shaped nozzle (120).

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