A z-axis zeroing method and 3D printing device

Abstract

The present application relates to the technical field of 3D printing, and particularly relates to a Z-axis zero-return method and a 3D printing device. The Z-axis zero-return method provided by the present application comprises: controlling the printing head and the printing platform to approach each other, and stopping the approaching operation when the printing head and the printing platform are in contact; and controlling the printing head and the printing platform to move away from each other, and stopping the moving-away operation when the printing head and the printing platform are separated. The pre-press lifting mechanism of the present application, in which the printing head and the printing platform first abut and then separate, can eliminate the deformation error caused by the slight deformation of the abutment and contact between the printing head and the printing platform, and realize high-precision self-adaptive zero-return of the Z-axis. Because the deformation error caused by the contact deformation between the printing head and the printing platform is eliminated, the accuracy of the zero-return position of the Z-axis is improved, and the printing quality of the first layer during printing can be ensured, the printing effect of subsequent layers is effectively guaranteed, and the precision, efficiency and quality of 3D printing are improved.

Description

Technical Field

[0001] This invention relates to the field of 3D printing technology, and particularly to a Z-axis zeroing method and a 3D printing device. Background Technology

[0002] 3D printing equipment is a device that can create three-dimensional objects by adding materials layer by layer based on three-dimensional model data. It typically uses fused deposition modeling (FDM) technology, which heats and melts materials such as plastics, resins, and metals and then deposits them layer by layer to ultimately form the desired three-dimensional structure.

[0003] In the field of 3D printing, precise calibration is crucial for ensuring high-quality printing, and Z-axis zeroing ensures that the print head's starting position in the vertical direction is accurate. However, existing Z-axis zeroing methods struggle to overcome the deformation error caused by the print head contacting the printing platform during zeroing. This results in the print head not being at the correct height when starting to print the first layer, leading to a discrepancy between the printed model and the design, thus affecting printing accuracy and model quality. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a Z-axis zeroing method and a 3D printing device.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution in a first aspect: a Z-axis zeroing method applied to a 3D printing device, the 3D printing device including a print head and a printing platform, characterized in that the Z-axis zeroing method includes the following steps: controlling the print head and the printing platform to move closer together, stopping the approaching operation when the print head and the printing platform come into contact; controlling the print head and the printing platform to move away from each other, stopping the moving away operation when the print head and the printing platform separate.

[0006] The control of the printhead and print platform to move closer together, and stopping the approach operation when the printhead and print platform come into contact, includes: during the approach process, acquiring a first detection value characterizing the contact between the printhead and the print platform; if the first detection value, after preset processing, is greater than or equal to a first threshold, the approach operation is stopped; the control of the printhead and print platform to move away from each other, and stopping the away operation when the printhead and print platform separate, includes: during the away process, acquiring a second detection value characterizing the separation between the printhead and the print platform; if the second detection value is less than or equal to a second threshold, the away operation is stopped; the first detection value and / or the second detection value are obtained based on detection elements, the detection elements including at least one of strain gauges, piezoelectric sensors, and eddy current sensors.

[0007] In one feasible implementation, after stopping the remote operation, the following steps are also included: obtaining the printing temperature and zeroing temperature of the print head; calculating the temperature difference between the printing temperature and the zeroing temperature; obtaining the temperature compensation height based on a preset temperature compensation rule; and adjusting the Z-axis position of the print head according to the temperature compensation height.

[0008] In one feasible implementation, the first detected value includes a first voltage value or a first current value, and / or the second detected value includes a second voltage value or a second current value.

[0009] In one feasible implementation, a first detection value is obtained to characterize the contact between the print head and the printing platform. If the first detection value is greater than or equal to a first threshold after preset processing, the approach operation is stopped. This includes the following steps: filtering a first voltage value or a first current value to obtain a first effective value; calculating a first signal change rate of the first effective value over a predetermined time; and stopping the approach operation if the first signal change rate exceeds the first threshold.

[0010] In one feasible implementation, during the separation process, a second detection value is acquired to characterize the separation of the printhead from the printing platform. If the second detection value is less than or equal to a second threshold, the separation operation is stopped. This includes the following steps: controlling the printhead and printing platform to move away step by step at a preset step distance; acquiring a second voltage value or a second current value; and stopping the separation operation if the second voltage value or the second current value is the same as the second threshold corresponding to the separation of the printhead and printing platform.

[0011] In one feasible implementation, controlling the print head and print platform to approach includes a coarse zeroing stage and a fine zeroing stage; in the coarse zeroing stage, the print head and print platform approach at a first speed; if the first detection value triggers a preset coarse zeroing stage contact condition, the Z-axis position of the contact between the print head and print platform is obtained as the Z-axis zero position of the coarse zeroing stage, and the print head and print platform enter the fine zeroing stage to approach at a second speed; if the first detection value triggers a preset fine zeroing stage contact condition, the approach operation stops; wherein, the first speed is greater than the second speed.

[0012] In one possible implementation, the printhead includes a nozzle, and further includes heating the nozzle.

[0013] In one possible implementation, the printhead includes a nozzle, and further includes methods for heating and wiping the nozzle.

[0014] In one possible implementation, the printhead includes a nozzle, and further includes heating the nozzle and then cooling the nozzle to a zero temperature.

[0015] In one feasible implementation, the printhead includes a nozzle, and further includes heating the nozzle and wiping the nozzle, and then cooling the nozzle to zero temperature.

[0016] To solve the above-mentioned technical problems, the present invention provides a second technical solution as follows: a 3D printing device, the 3D printing device including a processor and a memory, the memory storing a program or instructions that run on the processor, the program or instructions being executed by the processor to implement the above-mentioned Z-axis zeroing method.

[0017] Compared with existing technologies, the Z-axis zeroing method and 3D printing equipment provided by this invention have the following beneficial effects:

[0018] This invention provides a Z-axis zeroing method applied to a 3D printing device. The 3D printing device includes a print head and a printing platform. The Z-axis zeroing method includes the following steps: controlling the print head and the printing platform to move closer together; stopping the approach operation when the print head and the printing platform come into contact; and controlling the print head and the printing platform to move away from each other; stopping the away operation when the print head and the printing platform separate. Existing methods for zeroing the Z-axis of the print head and printing platform often only determine contact when the print head has already come into contact with the platform and generated contact pressure. This contact pressure indicates that the print head and platform have undergone slight deformation, resulting in a deformation error in the Z-axis zeroing position compared to the true Z-axis zeroing position. When the print head and platform are just separating, it means that they are in a critical state of just-contact. Using this position as the Z-axis zeroing position can eliminate the deformation error caused by the slight deformation during contact, thus achieving deformation error compensation. Through the aforementioned pre-pressure lifting mechanism of pressing down and then lifting the print head relative to the printing platform, high-precision adaptive zeroing of the Z-axis is achieved. This eliminates deformation errors caused by contact deformation, improves the accuracy of the Z-axis zeroing position, and ensures the printing quality of the first layer. The printing quality of subsequent layers is also effectively guaranteed, improving the accuracy, efficiency, and quality of 3D printing. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a flowchart illustrating the Z-axis zeroing method provided in the first embodiment of the present invention.

[0021] Figure 2 This is a flowchart illustrating step S1 of the Z-axis zeroing method provided in the first embodiment of the present invention.

[0022] Figure 3 This is a flowchart illustrating step S2 of the Z-axis zeroing method provided in the first embodiment of the present invention.

[0023] Figure 4 This is a schematic diagram of the temperature compensation process for the Z-axis zeroing method provided in the first embodiment of the present invention.

[0024] Figure 5 This is a flowchart illustrating step S12 of the Z-axis zeroing method provided in the first embodiment of the present invention.

[0025] Figure 6 This is a flowchart illustrating step S22 of the Z-axis zeroing method provided in the first embodiment of the present invention.

[0026] Figure 7 This is a flowchart illustrating step S11 of the Z-axis zeroing method provided in the first embodiment of the present invention.

[0027] Figure 8 This is a structural block diagram of the 3D printing device provided in the second embodiment of the present invention.

[0028] Explanation of reference numerals in the attached diagram:

[0029] 100. 3D printing equipment; 101. Processor; 102. Memory. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0031] Please see Figure 1 The first embodiment of the present invention provides a Z-axis zeroing method, applied to a 3D printing device. The 3D printing device includes a print head and a printing platform. The Z-axis zeroing method includes the following steps:

[0032] S1 controls the print head and print platform to move closer together. When the print head and print platform come into contact, the approach operation stops.

[0033] S2 controls the printhead and print platform to move away from each other. When the printhead and print platform separate, the moving-away operation stops.

[0034] Understandably, existing methods for zeroing the Z-axis of the printhead and print platform often only determine contact when the printhead, specifically the nozzles, have come into contact with the print platform and generated contact pressure. This contact pressure implies a slight deformation of both the printhead and the print platform, resulting in a deformation error in the Z-axis zeroing position compared to the true Z-axis zeroing position. When the printhead and print platform just separate, it signifies a critical state of just-contact. Using this position as the Z-axis zeroing position achieves high-precision adaptive zeroing of the Z-axis. By controlling the printhead and print platform to move closer, the approach operation stops when they make contact. Contact between the printhead and print platform refers to full contact, generating deformation and deformation pressure—a contact with inherent deformation error. Then, by controlling the printhead and print platform to move away from each other, the moving-away operation stops when the printhead and print platform separate. This separation refers to the printhead and print platform gradually moving away from contact with deformation pressure until they just separate. At this point, the printhead and print platform are in a critical state of just-contact without deformation error, eliminating deformation error caused by contact deformation. This pre-pressure lifting mechanism, which involves pressing down to contact the printhead and print platform before lifting it to separate, eliminates deformation error, provides deformation error compensation, and improves the accuracy of the Z-axis zeroing position. This ensures the printing quality of the first layer during printing, and effectively guarantees the printing quality of subsequent layers, improving overall printing accuracy and efficiency.

[0035] It should be noted that controlling the printhead and print platform to move closer or further apart can be achieved in several ways: the print platform is fixed, and the printhead moves closer or further away from the print platform; the printhead is fixed, and the print platform moves closer or further away from the printhead; or neither the printhead nor the print platform is fixed, and they move closer or further apart. No specific limitation is made here.

[0036] Please combine Figure 2 and Figure 3 Furthermore, controlling the printhead and print platform to move closer together, and stopping the approach operation when the printhead and print platform contact each other, includes:

[0037] S11, during the approach process, acquire the first detection value to characterize the contact between the print head and the printing platform;

[0038] S12, if the first detection value is greater than or equal to the first threshold after preset processing, stop the approach operation.

[0039] And / or control the printhead and print platform to move away, stopping the moving-away operation when the printhead and print platform separate, including:

[0040] S21, during the distancing process, acquire a second detection value to characterize the separation of the printhead from the printing platform;

[0041] S22, if the second detection value is less than or equal to the second threshold, stop the distance operation.

[0042] Understandably, by acquiring a first detection value characterizing the contact between the printhead and the printing platform during the approach process, and stopping the approach operation if the first detection value, after preset processing, is greater than or equal to a first threshold, the system can accurately quantify whether the printhead and printing platform are in contact. If the value of the first detection value after preset processing is greater than or equal to the first threshold, it corresponds to the deformation of the printhead and printing platform having achieved contact, at which point the approach operation stops. The preset processing may include filtering the data of the first detection value to ensure that the data is accurate and valid. Optionally, filtering may be used to reduce noise and interference. The system also calculates the rate of change of the first detection value to reflect the degree of deformation change of the printhead and printing platform during the approach, which is convenient for comparison with the first threshold to determine whether to stop the approach operation. Similarly, during the distancing process, a second detection value is acquired to characterize the separation of the print head and the printing platform. If the second detection value is less than or equal to the second threshold, the distancing operation is stopped. This allows for precise quantification of whether the print head and the printing platform are separated. If the second detection value is less than or equal to the second threshold, it means that the print head and the printing platform have changed from a state of contact and deformation to a state of separation without deformation error. At this point, the distancing operation is stopped, eliminating the deformation error caused by contact deformation and improving the accuracy of the Z-axis zero position.

[0043] Optionally, the first detection value used to characterize the contact between the print head and the printing platform and / or the second detection value used to characterize the separation between the print head and the printing platform can be obtained by using detection elements suitable for contact detection of minute deformation displacement, such as strain gauges, piezoelectric sensors, and eddy current sensors. The type and number of detection elements are not limited here.

[0044] Please see Figure 4 Furthermore, after ceasing the operation, the following steps are also included:

[0045] S31, obtain the printing temperature and zeroing temperature of the print head;

[0046] S32, calculates the temperature difference between the printing temperature and the zero temperature;

[0047] S33, based on the preset temperature compensation rules, obtains the temperature compensation height;

[0048] S34, adjusts the Z-axis position of the printhead according to the temperature compensation height.

[0049] Understandably, since Z-axis zeroing is required before 3D printing, there are two concepts in 3D printing: zeroing temperature and printing temperature. Zeroing temperature refers to the temperature of the print head nozzle during the Z-axis zeroing process, while printing temperature refers to the temperature of the print head nozzle during actual printing after zeroing. The above steps further implement temperature compensation. The background for temperature compensation is that the printing temperature corresponding to the print head nozzle during actual printing differs from the zeroing temperature corresponding to the Z-axis zeroing operation. This difference is to prevent material leakage caused by temperature variations in the print head during Z-axis zeroing. However, precisely because the printing temperature and zeroing temperature differ, the degree of thermal deformation of the print head nozzle differs, resulting in a temperature difference that will cause Z-axis height errors due to thermal expansion and contraction. Temperature compensation aims to eliminate the Z-axis height error caused by the temperature difference between the printing temperature and the zeroing temperature, adjusting the Z-axis zeroing position. Based on preset temperature compensation rules, the temperature compensation height corresponding to the temperature difference is calculated. Since the Z-axis position of the print head nozzle is the reference zero position after the operation stops, the temperature compensation height is added to adjust the Z-axis position of the print head nozzle based on this reference zero position, thereby realizing Z-axis height compensation of the print head and eliminating the Z-axis height error caused by temperature. Combined with deformation compensation and temperature compensation, deformation error and temperature-induced Z-axis height error are effectively eliminated, thereby further reducing Z-axis zeroing error. This is of great significance for improving the accuracy, quality and efficiency of 3D printing.

[0050] Optionally, obtaining the temperature compensation height based on a preset temperature compensation rule includes: multiplying the temperature difference between the printing temperature and the zero-temperature by a preset temperature coefficient parameter to obtain the temperature compensation height; wherein the printing temperature is higher than the zero-temperature. Since the printhead nozzle will continuously leak material at the printing temperature, affecting the Z-axis zeroing accuracy, the zeroing temperature is lower than the printing temperature. When the printhead nozzle performs Z-axis zeroing at the zeroing temperature, there will be no material leakage, thus not affecting the Z-axis zeroing accuracy. To address the deformation error caused by thermal expansion and contraction due to the inconsistency between the printing temperature and the zeroing temperature, since the dimensional change of the printhead nozzle material due to thermal expansion and contraction is approximately linear with temperature, the temperature compensation height is obtained by multiplying the temperature difference between the printing temperature and the zeroing temperature by a preset temperature coefficient parameter. The temperature compensation height refers to the distance the Z-axis zeroing position is adjusted to eliminate the Z-axis height error caused by the temperature difference between the printing temperature and the zeroing temperature. By using temperature compensation height to adjust the Z-axis position of the print head, the Z-axis height error caused by the temperature difference between the printing temperature and the zeroing temperature can be eliminated efficiently and conveniently. This avoids the impact of the inconsistency between the printing temperature and the zeroing temperature on the Z-axis zeroing, thereby improving printing accuracy and model printing quality.

[0051] Furthermore, the first detection value and / or the second detection value are obtained based on the detection element, which includes at least one of strain gauge, piezoelectric sensor, and eddy current sensor.

[0052] Understandably, by using the aforementioned detection elements to detect the first detection value used to characterize the contact between the print head and the printing platform and / or the second detection value used to characterize the separation between the print head and the printing platform, accurate detection and precise quantification of the contact or separation state between the print head and the printing platform can be achieved, improving the accuracy of the Z-axis zeroing operation and thus obtaining better print quality and printing efficiency.

[0053] It should be noted that, since strain gauge deformation causes a change in its resistance, depending on the hardware design, resistance detection can be converted into voltage or current detection. When using a strain gauge for detection, a first and / or second detection value can be set based on the voltage or current value. When a piezoelectric sensor is subjected to an external force, its two opposing surfaces generate equal amounts of positive and negative charges, resulting in an open-circuit voltage. This voltage value is proportional to the applied force and can be used to detect the magnitude of the force, thereby determining the positional relationship between the printhead and the printing platform. Therefore, when using a piezoelectric sensor for detection, a first and / or second detection value can be set based on the voltage value. Eddy current sensors are based on Faraday's law of electromagnetic induction and the eddy current effect. As the distance between the printhead nozzle and the printing platform changes, the coil impedance of the eddy current sensor changes and is converted into a change in voltage or current, which is then used to determine the positional relationship between the printhead and the printing platform. When using an eddy current sensor for detection, a first and / or second detection value can be set based on the voltage or current value.

[0054] Furthermore, the first detection value includes a first voltage value or a first current value, and the second detection value includes a second voltage value or a second current value.

[0055] Understandably, since the first detection value includes a first voltage value or a first current value, and the second detection value includes a second voltage value or a second current value, the first voltage value or the first current value refers to the voltage or current value measured by the detection element when the print head and the print platform are close together; the second voltage value or the second current value refers to the voltage or current value measured by the detection element when the print head and the print platform are far apart. By selecting voltage or current values ​​as detection signal values, there are advantages such as ease of measurement, ease of digital processing, and good stability.

[0056] As an optional implementation, the printing platform uses strain gauges to determine whether it is in contact with or separated from the print head. A strain gauge is a sensor that converts mechanical strain (deformation) into a change in resistance. When a strain gauge is subjected to an external force, its length and cross-sectional area change, resulting in a change in resistance. By sensing mechanical deformation and converting it into an electrical signal, the resistance change is measured through a Wheatstone bridge circuit, thereby achieving precise measurement of the Z-axis position. Specifically, the strain gauge is usually combined with three other resistors to form a Wheatstone bridge circuit. When the four resistance values ​​of the bridge are equal, the bridge is in a balanced state, and the output voltage is zero. When the resistance value of the strain gauge changes due to an external force, the balance of the bridge is broken. Depending on the hardware design, the first detection value is the first voltage or current value detected by the detection element, and / or the second detection value is the second voltage or current value detected by the detection element. Due to the high sensitivity of the strain gauge, precise detection of the Z-axis trigger position can be achieved, thereby improving the accuracy of the Z-axis zeroing operation. Precise distance control helps to achieve accurate Z-axis zeroing, resulting in better first-layer print quality. Compared with traditional mechanical limit switches, the Z-axis zeroing method using strain gauges is simpler to operate and more accurate; at the same time, it can reduce the impact of external environmental factors such as temperature and humidity on Z-axis zeroing accuracy, thereby improving the stability and reliability of printing.

[0057] As another optional implementation, when using a piezoelectric sensor for detection, the piezoelectric sensor generates an open-circuit voltage when subjected to an external force. The voltage value is proportional to the applied external force and can be used to detect the magnitude of the external force, thereby determining the positional relationship between the print head and the printing platform. Therefore, when using a piezoelectric sensor for detection, a first detection value can be set to the first voltage value detected by the detection element, and / or a second detection value can be set to the second voltage value detected by the detection element. The piezoelectric sensor can also achieve accurate detection.

[0058] As an alternative implementation, when using an eddy current sensor for detection, the coil impedance of the eddy current sensor changes as the distance between the printhead nozzle and the printing platform changes, and this change is converted into a change in voltage or current. This change is then used to determine the positional relationship between the printhead and the printing platform. When using an eddy current sensor for detection, a first detection value can be set to a first voltage or current value detected by the detection element, and / or a second detection value can be set to a second voltage or current value detected by the detection element. The eddy current sensor can also achieve accurate detection.

[0059] Please see Figure 5 Furthermore, a first detection value is obtained to characterize the contact between the print head and the printing platform. If the first detection value, after preset processing, is greater than or equal to a first threshold, the approach operation is stopped, including the following steps:

[0060] S121, filter the first voltage value or the first current value to obtain the first effective value;

[0061] S122, Calculate the first signal change rate of the first effective value over a predetermined time;

[0062] S123, if the rate of change of the first signal exceeds the first threshold, stop the approach operation.

[0063] Understandably, filtering the first voltage or current value to obtain the first effective value can reduce noise and interference, improving accuracy. This allows for more precise detection of the contact between the printhead and the printing platform, thereby improving the accuracy of Z-axis zeroing. As the printhead approaches the printing platform, the first voltage or current value detected by the sensing element changes along with the Z-axis coordinate of the printhead. After filtering to obtain the first effective value, calculating the first signal change rate of the first effective value over a predetermined time period can reflect the degree of deformation change of the printhead and printing platform during the approach process in real time. Optionally, calculating the first signal change rate of the first effective value over a predetermined time period specifically involves fitting a straight line to the first effective value using a preset fixed window length and obtaining the slope of the line as the first signal change rate. Fitting a straight line to the first effective value using a preset fixed window length means performing linear regression on the detected first effective value within a specific displacement distance of the printhead's Z-axis. The fixed window length means that the number of first effective values ​​used for fitting the linear regression is fixed each time. The slope of the calculated line is used as the first signal change rate. Calculating this rate enables dynamic monitoring of strain changes during the contact process between the print head and the printing platform. This dynamic monitoring helps to understand the mechanical changes during contact in real time, providing real-time feedback to the control algorithm. This allows for adaptive Z-axis adjustment, automatically adjusting the Z-axis position based on real-time detection data to improve printing accuracy. The first threshold is defined as the point at which the print head nozzle touches the printing platform when the first signal change rate equals the threshold. If the first signal change rate exceeds the threshold, a stop operation is triggered to prevent damage to the print head due to excessive pressure. This protection mechanism avoids hardware damage and extends the lifespan of the 3D printer. Automated data processing and threshold judgment reduce manual intervention and increase the automation level of the 3D printing process, which helps improve operational convenience, printing efficiency, and printing accuracy.

[0064] Optionally, the filtering process may include effective filtering methods such as mean filtering or median filtering to filter out false detections in the detection data and retain valid values. Mean filtering involves averaging the detection values ​​acquired within a sampling period, or averaging after removing maximum and minimum values. Median filtering involves taking the median of the detection values ​​acquired within a sampling period. Other filtering methods are not limited here.

[0065] Please see Figure 6 Furthermore, during the disengagement process, a second detection value is acquired to characterize the separation of the printhead from the printing platform. If the second detection value is less than or equal to a second threshold, the disengagement operation is stopped, including the following steps:

[0066] S221 controls the printhead and print platform to move away step by step at a preset step distance;

[0067] S222, obtain the second voltage value or the second current value;

[0068] S223, if the second voltage value or the second current value is the same as the second threshold for the separation of the corresponding printhead and print platform, stop the separation operation.

[0069] It should be noted that the preset step distance can be a fixed step distance, controlling the print head and the print platform to move away from each other at this fixed step distance. During the process of the print head moving away from the print platform, as the Z-axis coordinate of the print head changes, the second voltage value or the second current value also changes. The second voltage value or the second current value is used to represent the degree of deformation during the process of the print head moving away from the print platform. The significance of the second threshold is that when the second voltage value or the second current value is equal to the second threshold, it is determined that the print head nozzle has just detached from the print platform, and the moving away operation is stopped. The position of the print head nozzle at this time is taken as the Z-axis zero position with deformation compensation, making the Z-axis zero position more accurate.

[0070] Understandably, since the second detection value is either the second voltage value or the second current value, optionally, at least one of a strain gauge, piezoelectric sensor, or eddy current sensor can be used as the detection element to provide a reliable feedback signal, helping the control system to more accurately determine the contact state between the print head and the printing platform, thereby making the Z-axis zeroing operation more precise and improving the reliability of the entire printing process. After the print head contacts the printing platform, the print head often has already generated contact pressure with the printing platform before it is judged to be in contact with the printing platform. The contact pressure means that the print head and the printing platform have undergone slight deformation. At this time, the Z-axis zeroing position has a deformation error caused by contact compared with the true Z-axis zeroing position. By using a detection element to detect whether the print head and the printing platform are still in contact, when the print head and the printing platform just separate, this position is taken as the Z-axis zeroing position, which can eliminate this deformation error, realize deformation error compensation, and improve the accuracy of the Z-axis zeroing position.

[0071] Please see Figure 7 Furthermore, control the print head and print platform to approach the coarse zeroing stage and the fine zeroing stage;

[0072] S111, during the coarse zeroing stage, the print head and print platform approach each other at the first speed;

[0073] S112, if the first detection value triggers the preset coarse zeroing stage contact condition, the Z-axis position of the contact between the print head and the printing platform is obtained as the Z-axis zero position of the coarse zeroing stage, and the print head and the printing platform enter the fine zeroing stage and approach each other at the second speed.

[0074] S113, if the first detection value triggers the preset fine zeroing stage contact condition, stop the approach operation;

[0075] The first speed is greater than the second speed.

[0076] It should be noted that the contact condition for the coarse zeroing stage refers to the first signal change rate exceeding the first threshold of the coarse zeroing stage. When the first signal change rate obtained after filtering, fitting a straight line, and calculating the slope of the straight line from the first detected value exceeds the first threshold of the coarse zeroing stage, it triggers entry into the fine zeroing stage. The significance of the first threshold of the coarse zeroing stage is that when it is exceeded by the first signal change rate, it can be determined that the printhead nozzle has made contact with the printing platform, thus facilitating the rapid acquisition of a rough Z-axis zero position before entering the fine zeroing stage to obtain a more precise Z-axis zero position. The contact condition for the fine zeroing stage refers to the first signal change rate exceeding the first threshold of the fine zeroing stage. When the first signal change rate obtained after filtering, fitting a straight line, and calculating the slope of the straight line from the first detected value exceeds the first threshold of the fine zeroing stage, it triggers a stop approach operation. The significance of the first threshold of the fine zeroing stage is that when it is exceeded by the first signal change rate, the Z-axis position of the printhead nozzle can be determined as a more precise Z-axis zero position. The purpose of the coarse zeroing stage is to rapidly descend to obtain a rough Z-axis zero position, while the purpose of the fine zeroing stage is to reduce the approach speed to obtain a more accurate Z-axis zero position when the rough Z-axis zero position is known.

[0077] Understandably, controlling the printhead and print platform to approach each other involves two stages: coarse zeroing and fine zeroing. The first speed in the coarse zeroing stage is greater than the second speed in the fine zeroing stage, achieving segmented control to bring the printhead and print platform into close contact. Using a higher first speed in the coarse zeroing stage allows for rapid approach to the target position, reducing unnecessary waiting time and improving overall Z-axis zeroing efficiency. Rapid approach in the coarse zeroing stage reduces the chance of prolonged contact between the printhead and print platform at low speeds, thus reducing wear and damage. Using a lower second speed in the fine zeroing stage allows for more precise control of the printhead position, ensuring accurate contact between the printhead and print platform, which is crucial for subsequent printing accuracy. In the fine zeroing stage, due to the reduced speed, compared to the rapid approach in the coarse zeroing stage, the slower movement provides more feedback and adjustment time, improving the reliability of the zeroing operation. The system has more time to respond to the detection element signals, thus avoiding overshoot. Furthermore, since different printing materials and environmental conditions may require different zeroing strategies, by controlling the printhead to approach and contact the printing platform in stages, these changes can be flexibly adapted to, ensuring the reliability and accuracy of the zeroing operation.

[0078] Furthermore, the printhead includes a nozzle, and also includes heating the nozzle; or heating and wiping the nozzle; or heating the nozzle and then cooling the nozzle to zero temperature; or heating and wiping the nozzle and then cooling the nozzle to zero temperature.

[0079] Alternatively, after stopping the distance operation, check the zeroing result. If the zeroing result is abnormal, repeat the above Z-axis zeroing method.

[0080] It should be noted that the zeroing temperature refers to the temperature of the printhead nozzles when performing the Z-axis zeroing method. Optionally, the criterion for judging abnormal zeroing results is to calculate the deviation of the Z-axis zeroing positions obtained from multiple repetitions and set a standard value. The standard value represents the maximum tolerable deviation for a normal zeroing result. If the deviation exceeds the standard value, the zeroing result is abnormal and the Z-axis zeroing needs to be repeated; otherwise, the Z-axis zeroing is complete. Deviation calculation can be performed using methods such as variance, standard deviation, and coefficient of variation, and is not limited here.

[0081] Understandably, preheating the printhead nozzles allows them to reach a suitable temperature, ensuring the printing material melts fully. Wiping the nozzles removes residual particles and blockages, preventing residual material or blockages from affecting print accuracy and quality. Lowering the printhead nozzle temperature to zero prevents printhead leakage and does not affect Z-axis zeroing accuracy; the typically low zeroing temperature also ensures the safety of Z-axis zeroing operations. Checking the zeroing results after stopping the operation eliminates abnormal Z-axis zeroing results, ensuring the accuracy of Z-axis zeroing and preventing operational errors or malfunctions. This plays a crucial role in improving print quality, increasing print accuracy, and preventing print failures.

[0082] Please see Figure 8 The second embodiment of the present invention provides a 3D printing device 100, which includes a processor 101 and a memory 102. The memory 102 stores a program or instruction that runs on the processor 101. When the program or instruction is executed by the processor 101, it implements the Z-axis zeroing method of the first embodiment of the present invention.

[0083] Understandably, the 3D printing equipment 100 provided in the second embodiment of the present invention can achieve the same beneficial effects as the Z-axis zeroing method of the first embodiment of the present invention, and will not be described again here.

[0084] The present invention also provides the following embodiments:

[0085] Reference numeral 1, a Z-axis zeroing method, applied to a 3D printing device, the 3D printing device including a print head and a printing platform, characterized in that the Z-axis zeroing method includes the following steps:

[0086] Control the print head and print platform to move closer together; stop the movement when the print head and print platform come into contact.

[0087] Control the printhead and print platform to move away from each other. Stop the movement when the printhead and print platform separate.

[0088] Reference numeral 2, based on reference numeral 1, controls the printhead and print platform to move closer. When the printhead and print platform come into contact, the operation to stop moving closer includes: during the moving closer process, acquiring a first detection value to characterize the contact between the printhead and the print platform; if the first detection value, after preset processing, is greater than or equal to a first threshold, the moving closer operation is stopped; and / or controls the printhead and print platform to move away from each other. When the printhead and print platform separate, the operation to stop moving away includes: during the moving away process, acquiring a second detection value to characterize the separation between the printhead and the print platform; if the second detection value is less than or equal to a second threshold, the moving away operation is stopped.

[0089] Based on label 1, after stopping the movement away, label 3 also includes the following steps:

[0090] Obtain the print head's printing temperature and zeroing temperature;

[0091] Calculate the temperature difference between the printing temperature and the zero-temperature;

[0092] The temperature compensation height is obtained based on the preset temperature compensation rules;

[0093] The printhead Z-axis position is adjusted based on the temperature compensation height.

[0094] Reference numeral 4, based on reference numeral 2, the first detection value and / or the second detection value are obtained based on the detection element, which includes at least one of strain gauge, piezoelectric sensor, and eddy current sensor.

[0095] Reference numeral 5, based on reference numeral 4, includes a first detection value including a first voltage value or a first current value, and a second detection value including a second voltage value or a second current value.

[0096] Label 6, based on label 5, obtains a first detection value to characterize the contact between the print head and the printing platform. If the first detection value, after preset processing, is greater than or equal to a first threshold, the approach operation is stopped, including the following steps:

[0097] The first effective value is obtained by filtering the first voltage value or the first current value.

[0098] Calculate the rate of change of the first signal at the first effective value over a predetermined time period;

[0099] If the rate of change of the first signal exceeds the first threshold, stop the approach operation.

[0100] Label 7, based on label 5, involves acquiring a second detection value during the disengagement process to characterize the separation of the printhead from the printing platform. If the second detection value is less than or equal to a second threshold, the disengagement operation is stopped, including the following steps:

[0101] Control the print head and print platform to move away step by step at a preset step distance;

[0102] Obtain the second voltage value or the second current value;

[0103] If the second voltage value or the second current value is the same as the second threshold for the separation of the corresponding printhead and print platform, stop the distancing operation.

[0104] Number 8, based on number 2, controls the print head and print platform to approach the coarse zeroing stage and the fine zeroing stage;

[0105] During the coarse zeroing phase, the print head and print platform approach each other at the initial speed;

[0106] If the first detection value triggers the preset coarse zeroing stage contact condition, the Z-axis position of the contact between the print head and the printing platform is obtained as the Z-axis zero position of the coarse zeroing stage, and the print head and the printing platform enter the fine zeroing stage and approach each other at the second speed.

[0107] If the first detection value triggers the preset fine zeroing stage contact condition, stop the approach operation;

[0108] The first speed is greater than the second speed.

[0109] Reference numeral 9, based on reference numeral 3, the printhead includes a nozzle, and also includes heating the nozzle; or heating and wiping the nozzle; or heating the nozzle and then cooling it down to zero temperature; or heating and wiping the nozzle and then cooling it down to zero temperature.

[0110] Alternatively, after stopping the distance operation, check the zeroing result. If the zeroing result is abnormal, repeat the Z-axis zeroing method as described in any of the items labeled 1 to 8.

[0111] In the embodiments provided by this invention, it should be understood that "B corresponding to A" means that B is associated with A, and B can be determined based on A. However, it should also be understood that determining B based on A does not mean determining B solely based on A; B can also be determined based on A and / or other information.

[0112] It should be understood that the phrase "one embodiment" or "an embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of the invention. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Those skilled in the art should also recognize that the embodiments described in the specification are optional embodiments, and the actions and modules involved are not necessarily essential to the invention.

[0113] In various embodiments of the present invention, it should be understood that the sequence number of each process does not necessarily imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0114] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It is particularly important to note that each block in a block diagram and / or flowchart, or a combination of blocks in a block diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0115] Compared with the prior art, the Z-axis zeroing method and 3D printing equipment provided by the present invention have the following beneficial effects:

[0116] 1. This invention provides a Z-axis zeroing method applied to a 3D printing device, which includes a print head and a printing platform. The Z-axis zeroing method comprises the following steps: controlling the print head and printing platform to move closer together; stopping the approach operation when the print head and printing platform contact each other; and controlling the print head and printing platform to move away from each other; stopping the away operation when the print head and printing platform separate. Existing Z-axis zeroing methods for print heads and printing platforms often determine contact only when the print head, specifically the nozzle, has come into contact with the printing platform and generated contact pressure. This contact pressure indicates that the print head and printing platform have undergone slight deformation, resulting in a deformation error in the Z-axis zeroing position compared to the true Z-axis zeroing position. When the print head and printing platform just separate, it means that the print head and printing platform are in a critical state of just-contact. Using this position as the Z-axis zeroing position achieves high-precision adaptive zeroing of the Z-axis. By controlling the printhead and print platform to move closer together, the approaching operation stops when they make contact. This contact refers to full contact between the printhead and print platform, generating deformation and deformation pressure – a contact with inherent deformation error. Then, by controlling the printhead and print platform to move away from each other, the moving away operation stops when they separate. This separation refers to the printhead and print platform gradually moving away from contact with deformation pressure until they just separate. At this point, the printhead and print platform are in a critical state of just-contact without deformation error, eliminating deformation error caused by contact deformation. This pre-pressure lifting mechanism, which involves pressing down to make contact and then lifting to separate, eliminates deformation error, provides deformation error compensation, and improves the accuracy of the Z-axis zeroing position. This ensures the printing quality of the first layer and effectively guarantees the printing quality of subsequent layers, improving overall printing accuracy and efficiency.

[0117] 2. In this embodiment of the invention, controlling the printhead and the printing platform to approach each other, and stopping the approach operation when the printhead and the printing platform come into contact, includes: during the approach process, acquiring a first detection value to characterize the contact between the printhead and the printing platform; if the first detection value, after preset processing, is greater than or equal to a first threshold, stopping the approach operation. And / or controlling the printhead and the printing platform to move away from each other, and stopping the moving away operation when the printhead and the printing platform separate, includes: during the moving away process, acquiring a second detection value to characterize the separation between the printhead and the printing platform; if the second detection value is less than or equal to a second threshold, stopping the moving away operation. By acquiring a first detection value to characterize the contact between the printhead and the printing platform during the approach process, and stopping the approach operation if the first detection value, after preset processing, is greater than or equal to a first threshold, precise quantification of whether the printhead and the printing platform are in contact can be achieved. If the value of the first detection value after preset processing is greater than or equal to the first threshold, it corresponds to the deformation of the printhead and the printing platform having achieved contact, at which point the approach operation is stopped. The preset processing may include filtering the data of the first detection value to ensure its accuracy and validity. Optionally, filtering may be used to reduce noise and interference. The rate of change of the first detection value is calculated to reflect the degree of deformation change as the printhead approaches the printing platform, facilitating comparison with a first threshold to determine whether to stop the approaching operation. Similarly, during the moving-away process, a second detection value is acquired to characterize the separation of the printhead and printing platform. If the second detection value is less than or equal to the second threshold, the moving-away operation stops. This allows for precise quantification of whether the printhead and printing platform have separated. If the second detection value is less than or equal to the second threshold, it means that the printhead and printing platform have transitioned from a state of contact and deformation to a state of separation without deformation error. At this point, the moving-away operation stops, eliminating the deformation error caused by contact deformation and improving the accuracy of the Z-axis zeroing position.

[0118] 3. In this embodiment of the invention, after stopping the distance operation, the following steps are also included: obtaining the printing temperature and zeroing temperature of the print head; calculating the temperature difference between the printing temperature and the zeroing temperature; obtaining the temperature compensation height based on a preset temperature compensation rule; and adjusting the Z-axis position of the print head according to the temperature compensation height. Since a Z-axis zeroing operation is required before 3D printing, there are two concepts in 3D printing: zeroing temperature and printing temperature. The zeroing temperature refers to the temperature of the print head nozzle when performing the Z-axis zeroing method, while the printing temperature refers to the temperature of the print head nozzle during actual printing after zeroing. The above steps further realize temperature compensation. The background of temperature compensation is that the printing temperature corresponding to the print head nozzle during actual printing is different from the zeroing temperature corresponding to the Z-axis zeroing operation. This difference is to prevent material leakage caused by temperature affecting the print head during the Z-axis zeroing operation. However, because the printing temperature and the zeroing temperature are different, the degree of thermal deformation of the print head nozzle is different. Therefore, the resulting temperature difference will produce a Z-axis height error due to thermal expansion and contraction. Temperature compensation refers to eliminating the Z-axis height error caused by the temperature difference between the printing temperature and the zeroing temperature, and adjusting the Z-axis zeroing position. Based on preset temperature compensation rules, the temperature compensation height corresponding to the temperature difference is calculated. Since the Z-axis position of the print head nozzle is the reference zero position after the operation stops, the temperature compensation height is added to adjust the Z-axis position of the print head nozzle based on this reference zero position, thereby realizing Z-axis height compensation of the print head and eliminating the Z-axis height error caused by temperature. Combined with deformation compensation and temperature compensation, deformation error and temperature-induced Z-axis height error are effectively eliminated, thereby further reducing Z-axis zeroing error. This is of great significance for improving the accuracy, quality and efficiency of 3D printing.

[0119] 4. In the embodiments of the present invention, the first detection value and / or the second detection value are obtained based on detection elements, including at least one of strain gauges, piezoelectric sensors, and eddy current sensors. Using the above-mentioned detection elements to detect the first detection value characterizing the contact between the print head and the printing platform and / or the second detection value characterizing the separation between the print head and the printing platform enables accurate detection and precise quantification of the contact or separation state between the print head and the printing platform, improving the accuracy of the Z-axis zeroing operation, thereby obtaining better print quality and printing efficiency.

[0120] 5. In this embodiment of the invention, the first detection value includes a first voltage value or a first current value, and the second detection value includes a second voltage value or a second current value. Since the first detection value includes a first voltage value or a first current value, and the second detection value includes a second voltage value or a second current value, the first voltage value or the first current value refers to the voltage or current value measured by the detection element during the phase when the print head and the printing platform are close together; the second voltage value or the second current value refers to the voltage or current value measured by the detection element during the phase when the print head and the printing platform are far apart. By selecting voltage or current values ​​as the detection signal values, it has the advantages of being easy to measure, easy to digitize, and having good stability.

[0121] 6. In this embodiment of the invention, a first detection value for characterizing the contact between the print head and the printing platform is obtained. If the first detection value, after preset processing, is greater than or equal to a first threshold, the approach operation is stopped. This includes the following steps: filtering the first voltage value or the first current value to obtain a first effective value; calculating the first signal change rate of the first effective value over a predetermined time; and stopping the approach operation if the first signal change rate exceeds the first threshold. It is understood that filtering the first voltage value or the first current value to obtain the first effective value can reduce noise and interference and improve accuracy. This allows for more precise detection of the contact between the print head and the printing platform, thereby improving the accuracy of Z-axis zeroing. During the approach process between the print head and the printing platform, as the Z-axis coordinate of the print head changes, the first voltage value or the first current value detected by the detection element also changes. After filtering to obtain the first effective value, calculating the first signal change rate of the first effective value over a predetermined time can reflect the degree of deformation change between the print head and the printing platform during the approach process in real time. Optionally, calculating the first signal change rate of the first effective value over a predetermined time period specifically involves fitting a straight line to the first effective value using a preset fixed window length and obtaining the slope of the line as the first signal change rate. Fitting a straight line to the first effective value using a preset fixed window length means performing linear regression on the detected first effective value within a specific displacement distance of the print head's Z-axis. The fixed window length means that the number of first effective values ​​used for fitting the linear regression is fixed each time. The slope of the obtained line is used as the first signal change rate. Calculating the first signal change rate enables dynamic monitoring of strain changes during the contact process between the print head and the printing platform. This dynamic monitoring helps to understand the mechanical changes during the contact process in real time, providing real-time feedback for the control algorithm, thereby achieving adaptive Z-axis adjustment. It can automatically adjust the Z-axis position based on real-time detection data, improving printing accuracy. The significance of the first threshold is that when the first signal change rate equals the first threshold, it is considered that the print head nozzle has touched the printing platform. If the first signal change rate exceeds the first threshold, a stop approach operation is triggered, which can prevent the print head from being damaged due to excessive pressure. This protection mechanism can prevent hardware damage and extend the lifespan of the 3D printer. Through automated data processing and threshold judgment, it can reduce human intervention and improve the automation level of the 3D printing process, which helps to improve the ease of operation, printing efficiency and printing accuracy.

[0122] 7. In the embodiments of the present invention, during the separation process, a second detection value for characterizing the separation of the print head and the printing platform is obtained. If the second detection value is less than or equal to a second threshold, the separation operation is stopped. This includes controlling the print head and the printing platform to move away step by step at a preset step distance; obtaining a second voltage value or a second current value; and stopping the separation operation if the second voltage value or the second current value is the same as the second threshold for the separation of the corresponding print head and the printing platform. Since the second detection value is either the second voltage value or the second current value, optionally, at least one of a strain gauge, piezoelectric sensor, or eddy current sensor can be used as the detection element to provide a reliable feedback signal, helping the control system to more accurately determine the contact state between the print head and the printing platform, thereby making the Z-axis zeroing operation more precise and improving the reliability of the entire printing process. After the print head contacts the printing platform, the print head often has already generated contact pressure with the printing platform before it is judged to be in contact with the printing platform. The contact pressure means that the print head and the printing platform have undergone slight deformation. At this time, the Z-axis zeroing position has a deformation error caused by contact compared with the true Z-axis zeroing position. By using a detection element to detect whether the print head and the printing platform are still in contact, when the print head and the printing platform just separate, this position is taken as the Z-axis zeroing position, which can eliminate this deformation error, realize deformation error compensation, and improve the accuracy of the Z-axis zeroing position.

[0123] 8. In this embodiment of the invention, controlling the printhead and print platform to approach includes a coarse zeroing stage and a fine zeroing stage. In the coarse zeroing stage, the printhead and print platform approach at a first speed. If a first detection value triggers a preset coarse zeroing stage contact condition, the Z-axis position of the printhead and print platform contact is obtained as the Z-axis zero position of the coarse zeroing stage, and the printhead and print platform enter the fine zeroing stage to approach at a second speed. If the first detection value triggers a preset fine zeroing stage contact condition, the approach operation stops. The first speed is greater than the second speed. Because controlling the printhead and print platform to approach includes a coarse zeroing stage and a fine zeroing stage, and the first speed in the coarse zeroing stage is greater than the second speed in the fine zeroing stage, segmented control of the printhead and print platform to achieve close contact is realized. Using a higher first speed in the coarse zeroing stage allows for rapid approach to the target position, reducing unnecessary waiting time and improving the overall Z-axis zeroing adjustment efficiency. By rapidly approaching in the coarse zeroing stage, the chance of prolonged contact between the printhead and print platform at low speeds can be reduced, thereby reducing wear and damage between the printhead and print platform. Using a lower second speed during the fine zeroing phase allows for more precise control of the printhead position, ensuring accurate contact between the printhead and the printing platform. This is crucial for ensuring subsequent printing accuracy. In the fine zeroing phase, the reduced speed, compared to the rapid approach in the coarse zeroing phase, provides more feedback and adjustment time, improving the reliability of the zeroing operation. The system has more time to respond to the detection element signals, thus avoiding overshoot. Furthermore, since different printing materials and environmental conditions may require different zeroing strategies, phased control of the printhead's approach to the printing platform allows for flexible adaptation to these changes, ensuring the reliability and accuracy of the zeroing operation.

[0124] 9. In this embodiment of the invention, the printhead includes a nozzle, and further includes: heating the nozzle; or heating and wiping the nozzle; or heating the nozzle and then cooling it to a zero temperature; or heating and wiping the nozzle and then cooling it to a zero temperature; or, after stopping the remote operation, checking the zeroing result, and if the zeroing result is abnormal, repeating the above Z-axis zeroing method. Heating, through preheating, can bring the printhead nozzle to a suitable temperature, ensuring that the printing material is fully melted; wiping the nozzle can remove residual particles and blockages inside the printhead nozzle, avoiding residual printing material or blockages from affecting the accuracy and quality of printing; lowering the printhead nozzle temperature to the zero temperature can prevent printhead leakage and will not affect the Z-axis zeroing accuracy. The usually low zeroing temperature also ensures the safety of the Z-axis zeroing operation; checking whether the zeroing result is abnormal after stopping the remote operation can eliminate abnormal Z-axis zeroing results that do not meet the requirements, ensure the accuracy of the Z-axis zeroing operation, and avoid the impact of operational errors or malfunctions. This plays an important role in improving print quality, increasing print accuracy, and avoiding print malfunctions.

[0125] 10. This invention also provides a 3D printing device that has the same beneficial effects as the above-described Z-axis zeroing method, which will not be elaborated here.

[0126] The Z-axis zeroing method and 3D printing equipment disclosed in the embodiments of the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention. Any modifications, equivalent substitutions, and improvements made within the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A Z-axis zeroing method, applied to a 3D printing device, the 3D printing device comprising a print head and a printing platform, characterized in that, The Z-axis zeroing method includes the following steps: Control the print head and print platform to move closer together; stop the approach operation when the print head and print platform come into contact. Control the print head and print platform to move away from each other; stop the moving-away operation when the print head and print platform separate. The control of the printhead and print platform to move closer together, and stopping the approach operation when the printhead and print platform come into contact, includes: during the approach process, acquiring a first detection value characterizing the contact between the printhead and the print platform; if the first detection value, after preset processing, is greater than or equal to a first threshold, the approach operation is stopped; the control of the printhead and print platform to move away from each other, and stopping the away operation when the printhead and print platform separate, includes: during the away process, acquiring a second detection value characterizing the separation between the printhead and the print platform; if the second detection value is less than or equal to a second threshold, the away operation is stopped; the first detection value and / or the second detection value are obtained based on detection elements, the detection elements including at least one of strain gauges, piezoelectric sensors, and eddy current sensors.

2. The Z-axis zeroing method as described in claim 1, characterized in that: After stopping the operation, the following steps are also included: Obtain the printing temperature and zeroing temperature of the print head; Calculate the temperature difference between the printing temperature and the zero-temperature; The temperature compensation height is obtained based on the preset temperature compensation rules; The Z-axis position of the printhead is adjusted according to the temperature compensation height.

3. The Z-axis zeroing method as described in claim 1, characterized in that: The first detected value includes a first voltage value or a first current value, and the second detected value includes a second voltage value or a second current value.

4. The Z-axis zeroing method as described in claim 3, characterized in that: Obtain a first detection value characterizing the contact between the print head and the printing platform. If the first detection value, after preset processing, is greater than or equal to a first threshold, stop the approach operation, including the following steps: The first effective value is obtained by filtering the first voltage value or the first current value. Calculate the rate of change of the first signal at the first effective value over a predetermined time period; If the rate of change of the first signal exceeds the first threshold, stop the approach operation.

5. The Z-axis zeroing method as described in claim 3, characterized in that: During the disengagement process, a second detection value is acquired to characterize the separation of the printhead from the printing platform. If the second detection value is less than or equal to a second threshold, the disengagement operation is stopped, including the following steps: The print head and print platform are controlled to move away step by step at a preset step distance; Obtain the second voltage value or the second current value; If the second voltage value or the second current value is the same as the second threshold corresponding to the separation of the print head and the print platform, the distancing operation is stopped.

6. The Z-axis zeroing method as described in claim 1, characterized in that: Control the print head and print platform to approach the coarse zeroing stage and the fine zeroing stage; During the coarse zeroing phase, the print head and the print platform approach each other at a first speed; If the first detection value triggers the preset coarse zeroing stage contact condition, the Z-axis position of the contact between the print head and the printing platform is obtained as the Z-axis zero position of the coarse zeroing stage, and the print head and the printing platform enter the fine zeroing stage and approach each other at the second speed. If the first detection value triggers the preset fine zeroing stage contact condition, the approach operation is stopped. Wherein, the first speed is greater than the second speed.

7. The Z-axis zeroing method as described in claim 2, wherein the print head includes a nozzle, characterized in that: This also includes heating the nozzle.

8. The Z-axis zeroing method as described in claim 2, wherein the print head includes a nozzle, characterized in that: It also includes heating the nozzle and wiping the nozzle.

9. The Z-axis zeroing method as described in claim 2, wherein the print head includes a nozzle, characterized in that: It also includes heating the nozzle and then cooling it down to zero temperature.

10. The Z-axis zeroing method as described in claim 2, wherein the print head includes a nozzle, characterized in that: It also includes heating the nozzle, wiping the nozzle, and then cooling the nozzle back to zero temperature.

11. A 3D printing device, characterized in that, The 3D printing device includes a processor and a memory, the memory storing a program or instructions that run on the processor, the program or instructions which, when executed by the processor, implement the Z-axis zeroing method as described in any one of claims 1 to 10.

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