Z-axis zeroing method and 3D printing equipment

Abstract

The invention relates to the technical field of 3D printing, in particular to a Z-axis zeroing method and 3D printing equipment. The Z-axis zeroing method comprises the steps that a printing head and a printing platform are controlled to get close, and when the printing head makes contact with the printing platform, approaching operation is stopped; the printing head and the printing platform are controlled to be far away, and when the printing head and the printing platform are separated, far-away operation is stopped. Through a pre-pressing lifting mechanism that the printing head and the printing platform firstly abut against each other and then are separated from each other, deformation errors caused by tiny deformation of abutting contact of the printing head and the printing platform can be eliminated, Z-axis high-precision self-adaptive zeroing is achieved, and due to the fact that the deformation errors caused by contact deformation of the printing head and the printing platform are eliminated, the self-adaptive zeroing efficiency is improved. Therefore, the accuracy of the Z-axis return-to-zero position is improved, the printing quality of the first layer during printing can be ensured, the printing effect of the subsequent layers is also effectively guaranteed, and the precision, efficiency and quality of 3D printing are improved.

Description

[Technical field]

[0001] The present invention relates to the technical field of 3D printing, and in particular to a Z-axis zeroing method and a 3D printing device. [Background technology]

[0002] 3D printing equipment is a device that can manufacture three-dimensional objects by adding materials layer by layer according to three-dimensional model data. It usually uses Fused Deposition Modeling (FDM) technology to heat and melt materials such as plastics, resins, and metals, and then accumulate them layer by layer to eventually form the desired three-dimensional structure.

[0003] In the field of 3D printing, accurate calibration is the key to ensure high-quality printing, and Z-axis zeroing can ensure that the starting position of the print head in the vertical direction is accurate. However, the existing Z-axis zeroing method is difficult to overcome the deformation error caused by the contact between the print head and the printing platform during zeroing, which makes the print head inaccurate when starting to print the first layer, and it is impossible to start printing at the correct height, resulting in the printed model not being consistent with the design, affecting the printing accuracy and model printing quality. [Summary of the invention]

[0004] In order to solve the above problems, the present invention provides a Z-axis zeroing method and a 3D printing device.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions in the first aspect: a Z-axis zeroing method is applied to a 3D printing device, wherein the 3D printing device includes a print head and a printing platform, and is characterized in that the Z-axis zeroing method includes the following steps: controlling the print head and the printing platform to approach each other, and when the print head and the printing platform are in contact, the approaching operation is stopped; controlling the print head and the printing platform to move away from each other, and when the print head and the printing platform are separated, the moving away operation is stopped.

[0006] In a feasible embodiment, the print head and the printing platform are controlled to approach each other, and when the print head and the printing platform are in contact, the approach operation is stopped, including: during the approach process, obtaining a first detection value used to characterize the contact between the print head and the printing platform, and if the first detection value is greater than or equal to a first threshold after preset processing, the approach operation is stopped; and / or the print head and the printing platform are controlled to move away from each other, and when the print head and the printing platform are separated, the moving away operation is stopped, including: during the moving away process, obtaining a second detection value used to characterize the separation of the print head and the printing platform, and if the second detection value is less than or equal to a second threshold, the moving away operation is stopped.

[0007] In a feasible embodiment, after stopping the moving away operation, the following steps are also included: obtaining the printing temperature and the 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 a feasible implementation manner, the first detection value and / or the second detection value is obtained based on detection of a detection element, and the detection element includes at least one of a strain gauge, a piezoelectric sensor, and an eddy current sensor.

[0009] In a feasible implementation manner, the first detection value includes a first voltage value or a first current value, and / or the second detection value includes a second voltage value or a second current value.

[0010] In a feasible implementation, a first detection value for characterizing the contact between the print head and the printing platform is obtained, and if the first detection value is greater than or equal to a first threshold after preset processing, the approach operation is stopped, including the following steps: filtering the first voltage value or the first current value to obtain a first effective value; calculating a first signal change rate of the first effective value over a predetermined time period; if the first signal change rate exceeds a first threshold, the approach operation is stopped.

[0011] In a feasible embodiment, during the moving away process, a second detection value is obtained for characterizing the separation of the print head and the printing platform. If the second detection value is less than or equal to a second threshold, the moving away operation is stopped, including the following steps: controlling the print head and the printing platform to move away step by step with a preset step distance; obtaining a second voltage value or a 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 printing platform, the moving away operation is stopped.

[0012] In a feasible implementation manner, controlling the print head and the printing platform to approach each other includes a coarse zeroing stage and a fine zeroing stage; in the coarse zeroing stage, the print head and the printing platform approach each other at a first speed; if the first detection value triggers a preset coarse zeroing stage contact condition, the Z-axis position at which the print head and the printing platform are in contact 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 a second speed; if the first detection value triggers a preset fine zeroing stage contact condition, the approach operation is stopped; wherein the first speed is greater than the second speed.

[0013] In a feasible embodiment, the print head includes a nozzle, and also includes heating the nozzle; or, heating the nozzle and wiping the nozzle; or, heating the nozzle and then cooling the nozzle to a zeroing temperature; or, heating the nozzle, wiping the nozzle, and then cooling the nozzle to a zeroing temperature; or, detecting the zeroing result after stopping the distance operation, and if the zeroing result is abnormal, repeating the above-mentioned Z-axis zeroing method.

[0014] In order to solve the above technical problems, the second aspect of the present invention provides another technical solution as follows: a 3D printing device, the 3D printing device includes a processor and a memory, the memory stores a program or instruction running on the processor, and the program or instruction implements the above-mentioned Z-axis zeroing method when executed by the processor.

[0015] Compared with the prior art, the Z-axis zeroing method and 3D printing device provided by the present invention have the following beneficial effects:

[0016] A Z-axis zeroing method is provided in an embodiment of the present invention, which is 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 approach each other, and when the print head and the printing platform are in contact, stopping the approaching operation; controlling the print head and the printing platform to move away from each other, and when the print head and the printing platform are separated, stopping the moving away operation. Due to the existing Z-axis zeroing method of the print head and the printing platform, the print head is often judged to be in contact with the printing platform only when it has abutted against the printing platform and generated abutment pressure. The abutment pressure means that the print head and the printing platform have undergone a slight deformation. At this time, the Z-axis zeroing position has a deformation error caused by the contact compared to the actual Z-axis zeroing position. When the print head and the printing platform are just separated, it means that the print head and the printing platform are in a critical state of just contact. Taking this position as the Z-axis zeroing position can eliminate the deformation error caused by the slight deformation of the print head and the printing platform in abutment and contact, and realize deformation error compensation. Through the above-mentioned pre-pressure and lifting mechanism of the print head first pressing down to contact and then lifting and separating relative to the printing platform, high-precision adaptive zeroing of the Z-axis is realized, which can eliminate the deformation error caused by contact deformation and improve the accuracy of the Z-axis zeroing position, thereby ensuring the printing quality of the first layer during printing, and the printing effects of subsequent layers are also effectively guaranteed, thereby improving the accuracy, efficiency and quality of 3D printing.

Brief Description of the Drawings

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0018] Figure 1 It is a flowchart of the Z-axis zeroing method provided by the first embodiment of the present invention.

[0019] Figure 2 4 is a flow chart of step S1 of the Z-axis zeroing method provided in the first embodiment of the present invention.

[0020] Figure 3 4 is a flow chart of step S2 of the Z-axis zeroing method provided in the first embodiment of the present invention.

[0021] Figure 4 It is a schematic diagram of the flow of temperature compensation of the Z-axis zeroing method provided by the first embodiment of the present invention.

[0022] Figure 5 4 is a flow chart of step S12 of the Z-axis zeroing method provided in the first embodiment of the present invention.

[0023] Figure 6 4 is a flow chart of step S22 of the Z-axis zeroing method provided in the first embodiment of the present invention.

[0024] Figure 7 4 is a flow chart of step S11 of the Z-axis zeroing method provided in the first embodiment of the present invention.

[0025] Figure 8 3D printing device according to the second embodiment of the present invention.

[0026] Description of the accompanying drawings:

[0027] 100. 3D printing device; 101. processor; 102. memory. [Specific implementation method]

[0028] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and implementation examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0029] See also Figure 1 The first embodiment of the present invention provides a Z-axis zeroing method, which is 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:

[0030] S1, control the print head and the printing platform to approach each other, and when the print head and the printing platform are in contact, stop the approach operation;

[0031] S2, controls the print head and the printing platform to move away from each other. When the print head and the printing platform are separated, the moving away operation is stopped.

[0032] Understandably, due to the existing Z-axis zeroing method of the print head and the printing platform, the print head, specifically the nozzle of the print head, is often judged to be in contact with the printing platform only when the print head, specifically the nozzle of the print head, has abutted against the printing platform to generate abutment pressure. The abutment pressure means that the print head and the printing platform have undergone a slight deformation. At this time, the Z-axis zeroing position has a deformation error caused by contact compared to the true Z-axis zeroing position. When the print head and the printing platform are just separated, it means that the print head and the printing platform are in a critical state of just contact. This position is used as the Z-axis zeroing position, and high-precision adaptive zeroing of the Z axis is achieved. By controlling the print head and the printing platform to approach, when the print head and the printing platform are in contact, the approaching operation is stopped, wherein the contact between the print head and the printing platform refers to the full abutment between the print head and the printing platform, resulting in deformation and deformation pressure contact, and this contact is an abutment contact with deformation error. Then, the print head and the printing platform are controlled to move away from each other. When the print head and the printing platform are separated, the moving away operation is stopped. The separation of the print head and the printing platform means that the print head and the printing platform gradually move away from the contact with deformation pressure until they are just separated. At this time, the print head and the printing platform are in a critical state of just contacting without deformation error, eliminating the deformation error caused by contact deformation. The pre-pressure lifting mechanism of the print head and the printing platform first pressing down to contact and then lifting to separate can eliminate deformation errors, provide deformation error compensation, and improve the accuracy of the Z-axis zero position, thereby ensuring the printing quality of the first layer during printing. The printing effects of subsequent layers are also effectively guaranteed, improving the overall printing accuracy and printing efficiency.

[0033] It should be noted that the control of the print head and the printing platform to move closer or further away may be that the printing platform is fixed and the print head moves closer to or further away from the printing platform; or that the print head is fixed and the printing platform moves closer to or further away from the print head; or that the print head and the printing platform are not fixed and move closer to or further away from each other. This is not limited here.

[0034] Please combine Figure 2 and Figure 3 Further, controlling the print head and the printing platform to approach each other, when the print head and the printing platform are in contact, stopping the approach operation includes:

[0035] S11, during the approaching process, obtaining a first detection value for characterizing the contact between the print head and the printing platform;

[0036] S12: If the first detection value is greater than or equal to the first threshold after the preset processing, stop the approach operation.

[0037] And / or controlling the print head and the printing platform to move away from each other, when the print head and the printing platform are separated, stopping the moving away operation includes:

[0038] S21, during the process of moving away, obtaining a second detection value for indicating the separation of the print head from the printing platform;

[0039] S22: If the second detection value is less than or equal to the second threshold, stop the moving away operation.

[0040] It can be understood that by obtaining a first detection value used to characterize the contact between the print head and the printing platform during the approach process, if the first detection value is greater than or equal to the first threshold after the preset processing, the approach operation is stopped, and accurate quantification of whether the print head and the printing platform are in contact can be achieved. If the value of the first detection value after the preset processing is greater than or equal to the first threshold, the corresponding print head and the printing platform have achieved a deformation of abutting contact, and the approach operation is stopped at this time. The preset processing may include screening the validity of the data of the first detection value to ensure that the data is accurate and valid. Optionally, filtering processing is used for screening to reduce noise and interference; and the change rate of the first detection value is calculated to reflect the degree of deformation change when the print head and the printing platform are approaching, so as to facilitate comparison with the first threshold to determine whether to stop the approach operation. Also in the process of moving away, a second detection value is obtained 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 value, the moving away operation is stopped, which can achieve accurate 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 value, it means that the print head and the printing platform are transformed from a state of deformation caused by abutment contact to a state of just separation without deformation error. At this time, the moving away operation is stopped, which eliminates the deformation error caused by the abutment deformation and improves the accuracy of the Z-axis zero position.

[0041] 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 of the print head and the printing platform can be obtained by detection elements suitable for contact detection of small deformation displacements, such as strain gauges, piezoelectric sensors, and eddy current sensors. The type and number of detection elements are not limited here.

[0042] See also Figure 4 , further, after stopping the moving away operation, the following steps are also included:

[0043] S31, obtaining the printing temperature and zeroing temperature of the print head;

[0044] S32, calculating the temperature difference between the printing temperature and the zeroing temperature;

[0045] S33, obtaining a temperature compensation height based on a preset temperature compensation rule;

[0046] S34, adjusting the Z-axis position of the print head according to the temperature compensation height.

[0047] It is understandable that since the Z-axis zeroing operation needs to be performed 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 executing the Z-axis zeroing method, and the printing temperature refers to the temperature of the print head nozzle when it is officially printing after the zeroing is completed. The above steps further realize temperature compensation. The background of temperature compensation is that the printing temperature corresponding to the print head nozzle during formal printing is different from the zeroing temperature corresponding to the Z-axis zeroing operation. The difference between the two is to prevent the print head from being affected by temperature during the Z-axis zeroing operation and causing material leakage. However, because the printing temperature is different from the zeroing temperature, the degree of thermal deformation of the print head nozzle is different. Therefore, the temperature difference formed will produce a Z-axis height error caused by thermal expansion and contraction deformation. 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 the 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 distance operation is stopped, the temperature compensation height is added to adjust the Z-axis position of the print head nozzle on the basis of the reference zero position to achieve Z-axis height compensation for the print head, thereby eliminating the Z-axis height error caused by temperature. Combining deformation compensation and temperature compensation, the Z-axis height error caused by deformation error and temperature is effectively eliminated, thereby further reducing the Z-axis zeroing error, which is of great significance for improving the accuracy, quality and efficiency of 3D printing.

[0048] Optionally, based on the preset temperature compensation rule, obtaining the temperature compensation height includes: multiplying the temperature difference between the printing temperature and the zeroing temperature by a preset temperature coefficient parameter to obtain the temperature compensation height; wherein the printing temperature is higher than the zeroing temperature. Since the print head nozzle will always leak material at the printing temperature, affecting the Z-axis zeroing accuracy, the zeroing temperature is lower than the printing temperature, and the print head nozzle will not leak material when performing the Z-axis zeroing operation at the zeroing temperature, and will not affect the Z-axis zeroing accuracy. In order to solve the deformation error caused by the inconsistency between the printing temperature and the zeroing temperature and the thermal expansion and contraction, since the relationship between the dimensional change corresponding to the thermal expansion and contraction of the print head nozzle material and the temperature can be approximately linear, 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 adjusted to the zeroing position in the Z-axis direction in order to eliminate the Z-axis height error caused by the temperature difference between the printing temperature and the zeroing temperature. Using temperature compensation height to adjust the Z-axis position of the print head can efficiently and conveniently eliminate the Z-axis height error caused by the temperature difference between the printing temperature and the zeroing temperature, avoid the impact of the inconsistency between the printing temperature and the zeroing temperature on the Z-axis zeroing, and improve printing accuracy and model printing quality.

[0049] Furthermore, the first detection value and / or the second detection value is obtained based on detection by a detection element, and the detection element includes at least one of a strain gauge, a piezoelectric sensor, and an eddy current sensor.

[0050] It can be understood that the use of the above-mentioned 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 of the print head and the printing platform can achieve accurate detection, accurately quantify the state of contact or separation between the print head and the printing platform, and improve the accuracy of the Z-axis zeroing operation, thereby obtaining better printing quality and printing efficiency.

[0051] It should be noted that, since the deformation of the strain gauge will cause the resistance value of the strain gauge to change, according to different hardware designs, the resistance value detection can be converted into a detection voltage value or a current value. When the strain gauge is used for detection, the first detection value and / or the second detection value can be set to be obtained based on the voltage value or the current value detection. When the piezoelectric sensor is subjected to an external force, its two opposite surfaces will generate equal amounts of positive and negative charges, thereby generating an open circuit voltage. The voltage value is proportional to the applied external force, which can be used to detect the magnitude of the external force, and then used to determine the positional relationship between the print head and the printing platform. Therefore, when the piezoelectric sensor is used for detection, the first detection value and / or the second detection value can be set to be obtained based on the voltage value detection. The eddy current sensor is based on the Faraday electromagnetic induction principle and the eddy current effect. During the change of the distance between the print head nozzle and the printing platform, the coil impedance of the eddy current sensor changes and is converted into a change in voltage or current, which is used to determine the positional relationship between the print head and the printing platform. When the eddy current sensor is used for detection, the first detection value and / or the second detection value can be set to be obtained based on the voltage value or the current value detection.

[0052] Further, 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.

[0053] It can be understood that since the first detection value includes the first voltage value or the first current value, and the second detection value includes the second voltage value or the second current value, the first voltage value or the first current value refers to the voltage value or the current value measured by the detection element when the print head and the printing platform are close to each other; the second voltage value or the second current value refers to the voltage value or the current value measured by the detection element when the print head and the printing platform are far away from each other. By selecting the voltage value or the current value as the detection signal value, it has the advantages of easy measurement, easy digital processing and good stability.

[0054] As an optional implementation, the printing platform uses a strain gauge to determine whether the printing platform is in contact or separated from the print head. The strain gauge is a sensor that can convert mechanical strain, i.e., deformation, into resistance change. When the strain gauge is subjected to external force, its length and cross-sectional area will change, resulting in a change in resistance value. The strain gauge is used to sense the mechanical deformation and convert it into an electrical signal, and the resistance change is measured through a bridge circuit, thereby achieving accurate measurement of the Z-axis position. Specifically, the strain gauge usually forms a Wheatstone bridge circuit together with the other three resistors. 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 external force, the balanced state of the bridge is broken. Depending on the hardware design, the first detection value is the first voltage value or the first current value detected by the detection element and / or the second detection value is the second voltage value or the second current value detected by the detection element. Since the strain gauge has the characteristics of high sensitivity, it can realize accurate detection of the Z-axis trigger position, thereby improving the accuracy of the Z-axis zeroing operation. Accurate distance control helps to achieve accurate Z-axis zeroing, and better first-layer printing quality can be obtained. Compared with traditional mechanical limit switches, the Z-axis zeroing method using strain gauges is easy to operate and has higher accuracy. At the same time, it can reduce the influence of external environmental factors such as temperature and humidity on the Z-axis zeroing accuracy, and improve the stability and reliability of printing.

[0055] As another optional implementation, when a piezoelectric sensor is used for detection, the piezoelectric sensor generates an open circuit voltage when subjected to an external force, and the voltage value is proportional to the applied external force, which can be used to detect the magnitude of the external force, and then used to determine the positional relationship between the print head and the printing platform. Therefore, when a piezoelectric sensor is used for detection, the first detection value can be set to be the first voltage value detected by the detection element and / or the second detection value can be set to be the second voltage value detected by the detection element. Piezoelectric sensors can also achieve accurate detection.

[0056] As another optional implementation, when an eddy current sensor is used for detection, during the change of the distance between the print head nozzle and the printing platform, the coil impedance of the eddy current sensor changes and is converted into a change in voltage or current, so as to determine the positional relationship between the print head and the printing platform. When an eddy current sensor is used for detection, the first detection value can be set to be a first voltage value or a first current value detected by the detection element, and / or the second detection value can be set to be a second voltage value or a second current value detected by the detection element. Eddy current sensors can also achieve accurate detection.

[0057] See also Figure 5 , further, obtaining a first detection value for characterizing the contact between the print head and the printing platform, and if the first detection value is greater than or equal to a first threshold after a preset processing, stopping the approach operation, including the following steps:

[0058] S121, filtering the first voltage value or the first current value to obtain a first effective value;

[0059] S122, calculating a first signal change rate of the first effective value in a predetermined time period;

[0060] S123: If the first signal change rate exceeds a first threshold, stop the approach operation.

[0061] It can be understood that by filtering the first voltage value or the first current value to obtain the first effective value, noise and interference can be reduced and accuracy can be improved. In this way, the contact between the print head and the printing platform can be detected more accurately, thereby improving the accuracy of Z-axis zeroing. In the process of the print head and the printing platform approaching each other, 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, the first signal change rate of the first effective value in a predetermined time length is calculated, which can reflect the degree of deformation change of the print head and the printing platform in real time during the approach process. Optionally, calculating the first signal change rate of the first effective value in a predetermined time length is specifically to fit a straight line to the first effective value with a preset fixed window length, and to obtain the slope of the straight line as the first signal change rate. Fitting a straight line to the first effective value with a preset fixed window length means performing a linear regression on the first effective value detected within a specific displacement distance of the print head Z axis, and the fixed window length means that the number of first effective values ​​used for fitting the linear regression each time is fixed. The slope of the straight line obtained is used as the first signal change rate. Calculating the first signal change rate can realize dynamic monitoring of the strain change 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, and provide real-time feedback for the control algorithm, thereby realizing adaptive Z-axis adjustment. It can automatically adjust the Z-axis position according to real-time detection data to improve printing accuracy. The significance of the first threshold is that when the first signal change rate is equal to the first threshold, it is determined that the print head nozzle touches the printing platform at this time. If the first signal change rate exceeds the first threshold, it triggers the stop of the approach operation, which can prevent the print head from being damaged due to excessive pressure. This protection mechanism can avoid hardware damage and extend the service life of the 3D printer; through automated data processing and threshold judgment, it can reduce manual intervention and improve the degree of automation of the 3D printing process, which helps to improve the convenience of operation, printing efficiency and printing accuracy.

[0062] Optionally, the filtering process may include filtering methods such as mean filtering or median filtering that effectively filter error values ​​to filter out false positive values ​​in the detection data and retain valid values. Among them, mean filtering is to take the average of the detection values ​​obtained in a sampling time period, or to take the average after removing the maximum and minimum values, and median filtering is to take the median of the detection values ​​obtained in a sampling time period. Other filtering methods are not limited here.

[0063] See also Figure 6 Furthermore, during the process of moving away, a second detection value for characterizing the separation of the print head from the printing platform is obtained, and if the second detection value is less than or equal to a second threshold, the moving away operation is stopped, including the following steps:

[0064] S221, controlling the print head and the printing platform to move away step by step at a preset step distance;

[0065] S222, obtaining a second voltage value or a second current value;

[0066] S223: 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 printing platform, stop the separation operation.

[0067] It should be noted that the preset step size can be a fixed step size, and the print head and the printing platform are controlled to move away from each other at the fixed step size. In the process of the print head and the printing platform moving away from each other, 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 indicate the degree of deformation in the process of the print head and the printing platform moving away from each other. The second threshold value means that when the second voltage value or the second current value is equal to the second threshold value, it is determined that the print head nozzle has just left the printing platform, and the moving away operation is stopped. The position of the print head nozzle at this time is used as the Z-axis zero position with deformation compensation, so that the Z-axis zero position is more accurate.

[0068] It can be understood that since the second detection value is the second voltage value or the second current value, optionally, at least one of a strain gauge, a piezoelectric sensor, and an eddy current sensor is used as a detection element, which can provide a reliable feedback signal to help the control system more accurately determine the contact state of the print head and the printing platform, thereby making the Z-axis zeroing operation more accurate and improving the reliability of the entire printing process; after the print head contacts the printing platform, the print head has often abutted against the printing platform to generate abutment pressure before it is judged that the print head is in contact with the printing platform. The abutment pressure means that the print head and the printing platform have undergone a slight deformation. At this time, the Z-axis zeroing position has a deformation error caused by contact compared to the actual 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 are just separated, this position is used as the Z-axis zeroing position, which can eliminate this deformation error, achieve deformation error compensation, and improve the accuracy of the Z-axis zeroing position.

[0069] See also Figure 7 , further, controlling the print head and the printing platform to approach to include a coarse zeroing stage and a fine zeroing stage;

[0070] S111, in the rough zeroing stage, the print head and the printing platform approach each other at a first speed;

[0071] S112, if the first detection value triggers the preset coarse zeroing stage contact condition, the Z-axis position where the print head and the printing platform are in contact 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 a second speed;

[0072] S113, if the first detection value triggers the preset fine zeroing stage contact condition, stop the approach operation;

[0073] The first speed is greater than the second speed.

[0074] It should be noted that the contact condition in the coarse zeroing stage refers to the first signal change rate exceeding the first threshold of the coarse zeroing stage during the coarse zeroing stage. When the first signal change rate obtained by filtering, fitting a straight line, and finding the slope of the straight line of the first detection value exceeds the first threshold of the coarse zeroing stage, it triggers the fine zeroing stage. The first threshold of the coarse zeroing stage means that when it is exceeded by the first signal change rate, it can be determined that the print head nozzle is in contact with the printing platform, so as to facilitate the rapid acquisition of a rough Z-axis zero position, and then enter the fine zeroing stage to obtain a more accurate Z-axis zero position. The contact condition in the fine zeroing stage refers to the first signal change rate exceeding the first threshold of the fine zeroing stage during the fine zeroing stage. When the first signal change rate obtained by filtering, fitting a straight line, and finding the slope of the straight line of the first detection value exceeds the first threshold of the fine zeroing stage, it triggers the stop of the approach operation. The first threshold of the fine zeroing stage means that when it is exceeded by the first signal change rate, the Z-axis position of the print head nozzle can be determined as a more accurate Z-axis zero position. The purpose of the coarse zeroing stage is to quickly descend to obtain a rough Z-axis zero position, and the purpose of the fine zeroing stage is to know the rough Z-axis zero position, reduce the approach speed and obtain a more accurate Z-axis zero position.

[0075] It can be understood that since the control of the print head and the printing platform approaching includes a rough zeroing stage and a fine zeroing stage, the first speed of the rough zeroing stage is greater than the second speed of the fine zeroing, and the segmented control of the print head and the printing platform to achieve close contact is realized. Using a higher first speed in the rough zeroing stage can quickly approach the target position, reduce unnecessary waiting time, and improve the overall Z-axis zeroing adjustment efficiency. By quickly approaching in the rough zeroing stage, the chance of the print head and the printing platform being in contact for a long time at a low speed can be reduced, thereby reducing the wear and damage between the print head and the printing platform. Using a lower second speed in the fine zeroing stage can more accurately control the position of the print head and ensure that the contact position of the print head and the printing platform is accurate, which is crucial to ensuring the subsequent printing accuracy. In the fine zeroing stage, due to the reduced speed, compared with the rapid approach in the rough zeroing stage, the low-speed movement in the fine zeroing stage can provide more feedback and adjustment time, improve the reliability of the zeroing operation, and the system has more time to respond to the detection element signal, thereby avoiding overshoot. And because different printing materials and environmental conditions may require different zeroing strategies, by controlling the print head to be in close contact with the printing platform in stages, these changes can be flexibly adapted to ensure the reliability and accuracy of the zeroing operation.

[0076] Further, the print head includes a nozzle, and further includes heating the nozzle; or heating the nozzle and wiping the nozzle; or heating the nozzle and then cooling the nozzle to a zero temperature; or heating the nozzle and wiping the nozzle, and then cooling the nozzle to a zero temperature;

[0077] Or, after stopping the away operation, check the zeroing result. If the zeroing result is abnormal, repeat the above Z-axis zeroing method.

[0078] It should be noted that the zeroing temperature refers to the temperature of the print head nozzle when executing the Z-axis zeroing method. Optionally, the judgment standard for abnormal zeroing results is to calculate the deviation of the Z-axis zeroing position obtained by repeated multiple times, and set a standard value. The standard value means the maximum deviation tolerated by the normal zeroing result. If the deviation exceeds the standard value, the zeroing result is abnormal and the Z-axis zeroing needs to be performed again. If it does not exceed the standard value, the Z-axis zeroing is completed. The deviation calculation can be calculated by using methods such as variance, standard deviation, and coefficient of variation, which are not limited here.

[0079] Understandably, heating up the print head nozzle can reach an appropriate temperature through preheating to ensure that the printing material is fully melted; wiping the nozzle can remove residual particles and blockage problems inside the print head nozzle to prevent residual printing material or blockage from affecting the printing accuracy and quality; lowering the print head nozzle temperature to the zeroing temperature can prevent the print head from leaking material and will not affect the Z-axis zeroing accuracy. Usually, the zeroing temperature is low, which also ensures the safety of the Z-axis zeroing operation; after stopping the away operation, checking whether the zeroing result is abnormal 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 operating errors or failures, which plays an important role in improving printing quality, increasing printing accuracy, and avoiding printing failures.

[0080] See also 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 running on the processor 101. When the program or instruction is executed by the processor 101, the Z-axis zeroing method of the first embodiment of the present invention is implemented.

[0081] It can be understood that the 3D printing device 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 in detail herein.

[0082] The present invention also provides the following embodiments:

[0083] Reference numeral 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 comprises the following steps:

[0084] Control the print head and the printing platform to approach each other. When the print head and the printing platform are in contact, the approach operation stops.

[0085] Control the print head and the printing platform to move away from each other. When the print head and the printing platform are separated, the moving away operation stops.

[0086] Label 2, based on label 1, controls the print head and the printing platform to approach, and when the print head and the printing platform are in contact, stops the approach operation, including: during the approach process, obtains a first detection value used 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, stops the approach operation; and / or controls the print head and the printing platform to move away, and when the print head and the printing platform are separated, stops the moving away operation, including: during the moving away process, obtains a second detection value used to characterize the separation of the print head and the printing platform, if the second detection value is less than or equal to a second threshold, stops the moving away operation.

[0087] Label 3, based on label 1, after stopping the moving away operation, further includes the following steps:

[0088] Get the printing temperature and zeroing temperature of the print head;

[0089] Calculate the temperature difference between the printing temperature and the zero temperature;

[0090] Based on the preset temperature compensation rule, the temperature compensation height is obtained;

[0091] Adjust the Z-axis position of the print head according to the temperature compensation height.

[0092] Label 4, based on label 2, the first detection value and / or the second detection value is obtained based on detection of a detection element, and the detection element includes at least one of a strain gauge, a piezoelectric sensor, and an eddy current sensor.

[0093] Reference numeral 5, based on reference numeral 4, 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.

[0094] Reference number 6, based on reference number 5, obtaining a first detection value for characterizing the contact between the print head and the printing platform, and if the first detection value is greater than or equal to a first threshold after preset processing, stopping the approach operation, including the following steps:

[0095] Filtering the first voltage value or the first current value to obtain a first effective value;

[0096] Calculating a first signal change rate of the first effective value in a predetermined time period;

[0097] If the first signal change rate exceeds a first threshold, the approach operation is stopped.

[0098] Reference number 7, based on reference number 5, during the process of moving away, obtaining a second detection value for characterizing the separation of the print head and the printing platform, and if the second detection value is less than or equal to a second threshold, stopping the moving away operation, comprising the following steps:

[0099] Control the print head and printing platform to move away step by step at a preset step distance;

[0100] Acquiring a second voltage value or a second current value;

[0101] 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 printing platform, the moving away operation is stopped.

[0102] Reference numeral 8, based on reference numeral 2, controls the print head and the printing platform to approach each other including a rough zeroing stage and a fine zeroing stage;

[0103] In the rough zeroing stage, the print head and the printing platform approach each other at a first speed;

[0104] If the first detection value triggers the preset coarse zeroing stage contact condition, the Z-axis position where the print head and the printing platform are in contact 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;

[0105] If the first detection value triggers the preset fine zeroing stage contact condition, the approach operation is stopped;

[0106] The first speed is greater than the second speed.

[0107] Reference numeral 9, based on reference numeral 3, the print head includes a nozzle, and further includes heating the nozzle; or heating the nozzle and wiping the nozzle; or heating the nozzle and then cooling the nozzle to a zero temperature; or heating the nozzle and wiping the nozzle, and then cooling the nozzle to a zero temperature;

[0108] Or, after stopping the distance operation, the zeroing result is checked. If the zeroing result is abnormal, repeat the Z-axis zeroing method as any one of items 1 to 8.

[0109] In the embodiments provided by the present invention, it should be understood that "B corresponding to A" means that B is associated with A, and B can be determined according to A. However, it should also be understood that determining B according to A does not mean determining B only according to A, and B can also be determined according to A and / or other information.

[0110] It should be understood that the "one embodiment" or "an embodiment" mentioned throughout the specification means that the specific features, structures or characteristics related to the embodiment are included in at least one embodiment of the present invention. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. In addition, these specific features, structures or characteristics can be combined in one or more embodiments in any suitable manner. Those skilled in the art should also be aware that the embodiments described in the specification are all optional embodiments, and the actions and modules involved are not necessarily required by the present invention.

[0111] In various embodiments of the present invention, it should be understood that the size of the serial numbers of the above-mentioned processes does not mean the necessary 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.

[0112] The flow chart and block diagram in the accompanying drawings of the present invention illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present application. In this regard, each box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementation schemes, the functions marked in the box can also occur in a sequence different from that marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, which is determined based on the functions involved. It should be particularly noted that the combination of each box in the block diagram and / or flow chart, the block diagram and / or the box in the flow chart can be implemented by a dedicated hardware-based system that performs a specified function or operation, or can be implemented by a combination of dedicated hardware and computer instructions.

[0113] Compared with the prior art, the Z-axis zeroing method and 3D printing device provided by the present invention have the following beneficial effects:

[0114] 1. A Z-axis zeroing method is provided in an embodiment of the present invention, which is applied to a 3D printing device. The 3D printing device includes a print head and a printing platform, and is characterized in that the Z-axis zeroing method includes the following steps: controlling the print head and the printing platform to approach, and when the print head and the printing platform are in contact, the approaching operation is stopped; controlling the print head and the printing platform to move away, and when the print head and the printing platform are separated, the moving away operation is stopped. Due to the existing Z-axis zeroing method of the print head and the printing platform, it is often judged that the print head and the printing platform are in contact only when the print head, specifically the nozzle of the print head, has abutted against the printing platform to generate abutment pressure. The abutment pressure means that the print head and the printing platform have undergone a slight deformation. At this time, the Z-axis zeroing position has a deformation error caused by contact compared to the true Z-axis zeroing position. When the print head and the printing platform are just separated, it means that the print head and the printing platform are in a critical state of just contacting. This position is used as the Z-axis zeroing position, and high-precision adaptive zeroing of the Z-axis is achieved. By controlling the print head and the printing platform to approach, when the print head and the printing platform are in contact, the approach operation is stopped, wherein the contact between the print head and the printing platform refers to the full abutment between the print head and the printing platform, resulting in contact with deformation and deformation pressure, and this contact is an abutment contact with deformation error. Then, by controlling the print head and the printing platform to move away, when the print head and the printing platform are separated, the moving away operation is stopped, wherein the separation of the print head and the printing platform refers to the print head and the printing platform gradually moving away from the contact with deformation pressure until they are just separated. At this time, the print head and the printing platform are in a critical state of just contacting without deformation error, eliminating the deformation error caused by contact deformation. The above-mentioned pre-pressure lifting mechanism of the print head and the printing platform first pressing down to contact and then lifting to separate can eliminate deformation errors, provide deformation error compensation, and improve the accuracy of the Z-axis zero position, thereby ensuring the printing quality of the first layer during printing, and the printing effects of subsequent layers are also effectively guaranteed, improving the overall printing accuracy and printing efficiency.

[0115] 2. In the embodiment of the present invention, the print head and the printing platform are controlled to approach, and when the print head and the printing platform are in contact, the approach operation is stopped, including: during the approach process, a first detection value used to characterize the contact between the print head and the printing platform is obtained; if the first detection value is greater than or equal to the first threshold after being processed by a preset process, the approach operation is stopped. And / or the print head and the printing platform are controlled to move away, and when the print head and the printing platform are separated, the distance operation is stopped, including: during the distance process, a second detection value used to characterize the separation between the print head and the printing platform is obtained; if the second detection value is less than or equal to the second threshold, the distance operation is stopped. By obtaining the first detection value used to characterize the contact between the print head and the printing platform during the approach process, and stopping the approach operation if the first detection value is greater than or equal to the first threshold after being processed by a preset process, it is possible to accurately quantify whether the print head and the printing platform are in contact. If the value of the first detection value after being processed by a preset process is greater than or equal to the first threshold, the corresponding print head and the printing platform have achieved a deformation of abutting contact, and the approach operation is stopped at this time. The preset processing may include screening the validity of the data of the first detection value to ensure that the data is accurate and valid. Optionally, filtering processing may be used for screening to reduce noise and interference; and the rate of change of the first detection value is calculated to reflect the degree of deformation change when the print head and the printing platform are close, so as to facilitate comparison with the first threshold value to determine whether to stop the approach operation. Similarly, during the process of moving away, a second detection value is obtained 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 value, the moving away operation is stopped, which can accurately quantify whether the print head and the printing platform are separated. If the second detection value is less than or equal to the second threshold value, it means that the print head and the printing platform have changed from a state of deformation caused by abutment contact to a state of just separation without deformation error. At this time, the moving away operation is stopped, which eliminates the deformation error caused by the abutment deformation and improves the accuracy of the Z-axis zero position.

[0116] 3. After stopping the away operation in the embodiment of the present invention, the following steps are also included: obtaining the printing temperature and the 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 the preset temperature compensation rule; adjusting the Z-axis position of the print head according to the temperature compensation height. Since the Z-axis zeroing operation needs to be performed before 3D printing, there are two concepts of zeroing temperature and printing temperature in 3D printing. The zeroing temperature refers to the temperature of the print head nozzle when executing the Z-axis zeroing method, and the printing temperature refers to the temperature of the print head nozzle when the printing is formally printing after the zeroing is completed. The above steps further realize temperature compensation. The background of temperature compensation is that the printing temperature corresponding to the print head nozzle during formal printing is different from the zeroing temperature corresponding to the Z-axis zeroing operation. The difference between the two is to prevent the print head from being affected by temperature during the Z-axis zeroing operation and causing leakage. However, because the printing temperature is different from the zeroing temperature, the degree of thermal deformation of the print head nozzle is different, so the temperature difference formed will produce a Z-axis height error caused by thermal expansion and contraction deformation. 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 the 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 distance operation is stopped, the temperature compensation height is added to adjust the Z-axis position of the print head nozzle on the basis of the reference zero position to achieve Z-axis height compensation for the print head, thereby eliminating the Z-axis height error caused by temperature. Combining deformation compensation and temperature compensation, the Z-axis height error caused by deformation error and temperature is effectively eliminated, thereby further reducing the Z-axis zeroing error, which is of great significance for improving the accuracy, quality and efficiency of 3D printing.

[0117] 4. The first detection value and / or the second detection value in the embodiment of the present invention are obtained based on the detection of the detection element, and the detection element includes at least one of a strain gauge, a piezoelectric sensor, and an eddy current sensor. The above detection element is selected 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, which can achieve accurate detection, accurately quantify the state of contact or separation between the print head and the printing platform, and improve the accuracy of the Z-axis zeroing operation, thereby obtaining better printing quality and printing efficiency.

[0118] 5. In the embodiment of the present 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 the first voltage value or the first current value, and the second detection value includes the second voltage value or the second current value, the first voltage value or the first current value refers to the voltage value or the current value measured by the detection element when the print head and the printing platform are close to each other; the second voltage value or the second current value refers to the voltage value or the current value measured by the detection element when the print head and the printing platform are far away from each other. By selecting the voltage value or the current value as the detection signal value, it has the advantages of easy measurement, easy digital processing and good stability.

[0119] 6. In the embodiment of the present invention, obtaining a first detection value for characterizing the contact between the print head and the printing platform, if the first detection value is greater than or equal to the first threshold after the preset processing, stopping the approach operation, 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 in a predetermined time length; if the first signal change rate exceeds the first threshold, stopping the approach operation. It can be understood that by filtering the first voltage value or the first current value to obtain the first effective value, noise and interference can be reduced and accuracy can be improved. In this way, the contact between the print head and the printing platform can be detected more accurately, thereby improving the accuracy of Z-axis zeroing. In the process of the print head and the printing platform approaching, 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, the first signal change rate of the first effective value in a predetermined time length is calculated, which can reflect the degree of deformation change of the print head and the printing platform in real time during the approach process. Optionally, calculating the first signal change rate of the first effective value in a predetermined time length is specifically to fit a straight line to the first effective value with a preset fixed window length, and to obtain the slope of the straight line as the first signal change rate. Fitting a straight line to the first effective value with a preset fixed window length means performing a linear regression on the first effective value detected within a specific displacement distance of the print head Z axis, and the fixed window length means that the number of first effective values ​​used for fitting the linear regression each time is fixed. The slope of the straight line obtained is used as the first signal change rate, and calculating the first signal change rate can realize 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, and provide real-time feedback for the control algorithm, thereby realizing adaptive Z-axis adjustment, and being able to automatically adjust the Z-axis position according to real-time detection data to improve printing accuracy. The first threshold means that when the first signal change rate is equal to the first threshold, it is determined that the print head nozzle touches the printing platform at this time. If the first signal change rate exceeds the first threshold, it triggers the stop approach operation, which can prevent the print head from being damaged due to excessive pressure. This protection mechanism can avoid hardware damage and extend the service life of the 3D printer; through automated data processing and threshold judgment, it can reduce manual intervention and improve the degree of automation of the 3D printing process, which helps to improve the convenience of operation, printing efficiency and printing accuracy.

[0120] 7. In an embodiment of the present invention, during the moving away process, a second detection value for characterizing the separation of the print head and the printing platform is obtained, and if the second detection value is less than or equal to a second threshold, the moving away operation is stopped, including 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; 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 printing platform, the moving away operation is stopped. Since the second detection value is a second voltage value or a second current value, optionally, at least one of a strain gauge, a piezoelectric sensor, and an eddy current sensor is used as a detection element, which can provide a reliable feedback signal to help the control system more accurately determine the contact state between the print head and the printing platform, thereby making the Z-axis zeroing operation more accurate and improving the reliability of the entire printing process; after the print head contacts the printing platform, the print head has often abutted against the printing platform to generate abutment pressure before it is judged that the print head is in contact with the printing platform. The abutment pressure means that the print head and the printing platform have undergone a slight deformation. At this time, the Z-axis zeroing position has a deformation error caused by contact compared to the actual 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 are just separated, this position is used as the Z-axis zeroing position, which can eliminate this deformation error, achieve deformation error compensation, and improve the accuracy of the Z-axis zeroing position.

[0121] 8. In the embodiment of the present invention, the control of the print head and the printing platform approaching includes a rough zeroing stage and a fine zeroing stage; in the rough zeroing stage, the print head and the printing platform approach at a first speed; if the first detection value triggers the preset rough zeroing stage contact condition, the Z-axis position where the print head and the printing platform are in contact is obtained as the Z-axis zero position of the rough zeroing stage, and the print head and the printing platform enter the fine zeroing stage and approach at a 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. Since the control of the print head and the printing platform approaching includes a rough zeroing stage and a fine zeroing stage, the first speed of the rough zeroing stage is greater than the second speed of the fine zeroing, and the segmented control of the print head and the printing platform to achieve close contact is realized. Using a higher first speed in the rough zeroing stage can quickly approach the target position, reduce unnecessary waiting time, and improve the overall Z-axis zeroing adjustment efficiency. By quickly approaching in the rough zeroing stage, the chance of the print head and the printing platform being in contact for a long time at a low speed can be reduced, thereby reducing wear and damage between the print head and the printing platform. Using a lower second speed in the fine zeroing stage can more accurately control the position of the print head and ensure the precise contact position between the print head and the printing platform, which is crucial to ensuring the subsequent printing accuracy. In the fine zeroing stage, due to the reduced speed, compared with the rapid approach in the coarse zeroing stage, the slow movement in the fine zeroing stage can provide more feedback and adjustment time, improve the reliability of the zeroing operation, and the system has more time to respond to the detection element signal to avoid overshoot. And because different printing materials and environmental conditions may require different zeroing strategies, by controlling the print head to be in close contact with the printing platform in stages, these changes can be flexibly adapted to ensure the reliability and accuracy of the zeroing operation.

[0122] 9. In the embodiment of the present invention, the print head includes a nozzle, and further includes heating the nozzle; or heating the nozzle and wiping the nozzle; or heating the nozzle and then cooling the nozzle to a zeroing temperature; or heating the nozzle and wiping the nozzle, and then cooling the nozzle to a zeroing temperature; or after stopping the away operation, the zeroing result is detected, and if the zeroing result is abnormal, the above Z-axis zeroing method is repeated. Heating can make the print head nozzle reach a suitable temperature through preheating to ensure that the printing material is fully melted; wiping the nozzle can remove the residual particles and blockage problems inside the print head nozzle, and avoid residual printing materials or blockage affecting the accuracy and quality of printing; reducing the temperature of the print head nozzle to the zeroing temperature can avoid leakage of the print head, and will not affect the Z-axis zeroing accuracy. Usually, the zeroing temperature is low, which also ensures the safety of the Z-axis zeroing operation; after stopping the away operation, detecting whether the zeroing result is abnormal can eliminate the abnormal Z-axis zeroing result that does not meet the requirements, ensure the accuracy of the Z-axis zeroing operation, avoid the impact of operating errors or failures, and play an important role in improving printing quality, increasing printing accuracy, and avoiding printing failures.

[0123] 10. An embodiment of the present invention further provides a 3D printing device, which has the same beneficial effects as the above-mentioned Z-axis zeroing method, and will not be described in detail here.

[0124] A Z-axis zeroing method and a 3D printing device disclosed in an embodiment of the present invention are introduced in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as a limitation on the present invention. Any modifications, equivalent substitutions and improvements made within the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A Z-axis zeroing method, applied to a 3D printing device, wherein the 3D printing device comprises a print head and a printing platform, characterized in that: The Z-axis zeroing method comprises the following steps: Controlling the print head and the printing platform to approach each other, and stopping the approaching operation when the print head and the printing platform are in contact; The print head and the printing platform are controlled to move away from each other, and when the print head and the printing platform are separated, the moving away operation is stopped.

2. The Z-axis zeroing method according to claim 1, characterized in that: Controlling the print head and the printing platform to approach each other, and when the print head and the printing platform are in contact, stopping the approaching operation includes: during the approaching process, obtaining a first detection value used to characterize the contact between the print head and the printing platform, and if the first detection value is greater than or equal to a first threshold after preset processing, stopping the approaching operation; and / or controlling the print head and the printing platform to move away from each other, and when the print head and the printing platform are separated, stopping the moving away operation includes: during the moving away process, obtaining a second detection value used to characterize the separation of the print head and the printing platform, and if the second detection value is less than or equal to a second threshold, stopping the moving away operation.

3. The Z-axis zeroing method according to claim 1, wherein: After stopping the away operation, the following steps are also included: Obtaining a printing temperature and a zeroing temperature of the print head; Calculate the temperature difference between the printing temperature and the zero temperature; Based on the preset temperature compensation rule, the temperature compensation height is obtained; The Z-axis position of the print head is adjusted according to the temperature compensation height.

4. The Z-axis zeroing method according to claim 2, characterized in that: The first detection value and / or the second detection value is obtained based on detection of a detection element, and the detection element includes at least one of a strain gauge, a piezoelectric sensor, and an eddy current sensor.

5. The Z-axis zeroing method according to claim 4, characterized in that: 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.

6. The Z-axis zeroing method according to claim 5, characterized in that: Obtaining a first detection value for characterizing the contact between the print head and the printing platform, and stopping the approach operation if the first detection value is greater than or equal to a first threshold after preset processing, including the following steps: Filtering the first voltage value or the first current value to obtain a first effective value; Calculating a first signal change rate of the first effective value in a predetermined time period; If the first signal change rate exceeds a first threshold, the approach operation is stopped.

7. The Z-axis zeroing method according to claim 5, characterized in that: During the process of moving away, obtaining a second detection value for indicating the separation of the print head from the printing platform, and stopping the moving away operation if the second detection value is less than or equal to a second threshold, including the following steps: Controlling the print head and the printing platform to move away step by step at a preset step distance; Acquiring a second voltage value or a second current value; If the second voltage value or the second current value is the same as a second threshold corresponding to the separation of the print head and the printing platform, the moving away operation is stopped.

8. The Z-axis zeroing method according to claim 2, characterized in that: Controlling the print head and the printing platform to approach each other includes a coarse zeroing stage and a fine zeroing stage; In the rough zeroing stage, the print head and the printing platform approach each other at a first speed; If the first detection value triggers a preset coarse zeroing stage contact condition, the Z-axis position where the print head and the printing platform are in contact 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 a second speed; If the first detection value triggers a preset fine zeroing stage contact condition, the approach operation is stopped; Wherein, the first speed is greater than the second speed.

9. The Z-axis zeroing method according to claim 3, wherein the print head comprises a nozzle, characterized in that: It also includes heating the nozzle; or, heating the nozzle and wiping the nozzle; or, heating the nozzle and then cooling the nozzle to a zero temperature; or, heating the nozzle and wiping the nozzle, and then cooling the nozzle to a zero temperature; Or, after stopping the moving away operation, the zeroing result is detected, and if the zeroing result is abnormal, the Z-axis zeroing method as described in any one of claims 1 to 8 is repeated.

10. A 3D printing device, characterized in that: The 3D printing device includes a processor and a memory, wherein the memory stores a program or instruction running on the processor, and when the program or instruction is executed by the processor, the Z-axis zeroing method according to any one of claims 1 to 9 is implemented.

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