3D printing contact type needle aligning system, 3D printing device and needle aligning method

Abstract

The invention discloses a 3D printing contact type needle aligning system, a 3D printing device and a needle aligning method, and belongs to the technical field of 3D printing. The 3D printing contact type needle aligning system comprises a Z-axis sliding module, a position measuring module, a printing head and a capacitive sensor. The Z-axis sliding module is arranged above the printing head and used for controlling the printing head to move up and down; the position measuring module is used for measuring the relative position of each component; the capacitive sensor is used for judging whether a printing needle is in contact with the capacitive sensor or not through temperature change caused by internal coil current, so that needle alignment is realized; the 3D printing device comprises the contact type needle aligning system. According to the 3D printing contact type needle aligning system, whether the printing needle head makes contact with the capacitive sensor or not is judged through the temperature change of the coil in the capacitive sensor, so that high-precision needle aligning is achieved, and the needle aligning precision can at least reach 1 micron.

Description

Technical Field

[0001] The present invention belongs to the technical field of 3D printing, and in particular relates to a 3D printing contact type needle alignment system, a 3D printing device and a needle alignment method. Background Art

[0002] At present, in the 3D printing process, ceramic needles are commonly used as printing needles. The length of the ceramic needle tip is about 10mm, and the shape of the needle tip is tapered and evenly distributed, with uniform stress release, high hardness, and non-fragile characteristics. When the tool setting instrument reads the pressure of the ceramic needle, the needle tip is not easy to deform or break. However, with the development of industry technology, when filling holes with a diameter of 30-80μm and a length of 50-80mm, the existing tapered ceramic needles can no longer meet the work requirements. They cannot complete the work of inserting into the hole filling, and a glass needle with a diameter of 18-50μm and a needle tip length of not less than 100mm is required for printing. The tip of this glass needle is a narrow hourglass shape, which will break under very small pressure. Due to the fragility of the material caused by the shape of the glass needle, when the tool setting instrument fails to reach a pressure sufficient to generate a signal when using the above technology to align the needle, the glass needle tip has broken. In the existing technology, usually industrial pressure tool setting instrument, light transmission laser detection sensor, high-precision contact digital sensor or bridge strain gauge can be used for needle setting, but there are the following technical problems:

[0003] The industrial pressure tool setting instrument changes the relative position of the grating scale according to the pressure, and after judging the relative displacement of the grating scale, reads the electrical signal to capture the needle tip position. In use, the trigger pressure threshold of the grating scale of the tool setting instrument is about 0.3N. Since the ceramic needle has good stability and the maximum stress of the needle tip being broken by force is large, it can be used as a module for capturing the position of the ceramic needle tip. However, when using a glass needle, the glass needle has not reached the trigger threshold and has been broken, so it cannot be used as a needle setting module.

[0004] The light-transmitting laser detection sensor uses a laser transmitter and a laser receiver to form a laser light curtain. The needle tip passes through the laser light curtain, blocking part of the laser and changing the amount of light passing through to determine whether the needle tip has reached the specified position. The ceramic needle is opaque, so the needle tip position can be captured when it initially enters the light curtain. The glass needle is transparent, so the needle tip position cannot be captured when it passes through the laser light curtain.

[0005] The technical issues of high-precision contact digital sensors (industrial probes as spring pressure sensors) are similar to those of industrial pressure tool setting instruments;

[0006] The bridge strain gauge will bend after being squeezed and deformed, and the curvature changes linearly with the squeezing pressure, but the tip of the glass needle is too thin to bend the strain gauge.

[0007] It can be seen that it is currently technically difficult to achieve high-precision needle alignment for slender glass needles. Therefore, it is urgent to develop a needle alignment system and method that can solve the problem of fragile glass needles during contact needle alignment. Summary of the invention

[0008] The main purpose of the present invention is to provide a 3D printing contact needle alignment system, a 3D printing device and a needle alignment method to solve the technical problem of the prior art that the glass needle is easily broken during the contact needle alignment process.

[0009] In a first aspect, the present invention provides a 3D printing contact needle alignment system, comprising a Z-axis sliding module, a position measurement module, a print head and a capacitive sensor;

[0010] The Z-axis sliding module is arranged above the print head and is used to control the up and down movement of the print head. A printing needle is arranged below the print head.

[0011] The position measurement module is used to measure the relative positions of various components;

[0012] The capacitive sensor uses the temperature change caused by the internal coil current to determine whether the printing needle is in contact with the capacitive sensor, thereby achieving needle alignment.

[0013] Further, the capacitive sensor includes a contact sensing surface, a temperature sensor, a current controller, an electro-optical position sensor, a support rod, a sensing axis point and a coil;

[0014] The contact sensing surface is arranged above the support rod for contacting with the printing needle, and a sensing axis point is arranged below the support rod;

[0015] The photoelectric position sensor is used to detect the change of the relative position of the support rod and control the current controller to regulate the current, and the temperature of the coil resistance changes accordingly;

[0016] The temperature sensor is used to detect the temperature change of the coil resistance.

[0017] The working principle of the capacitive sensor is as follows: when an object contacts the contact sensing surface of the capacitive sensor, the object's own gravity will cause the support rod connected to the contact sensing surface inside the capacitive sensor to tilt. After the electro-optical position sensor detects the position change information of the support rod, it controls the increase of the current flowing through the compensation coil, and under the support of the sensing axis point, the support rod returns to the original equilibrium position; the coil is located in the permanent magnet, and the change of the coil current will bring about a change in the magnetic flux and then a change in temperature. Finally, the relevant information of the object is obtained by reversely detecting the temperature change, and the reading is displayed on the capacitive sensor.

[0018] Furthermore, the system also includes a visual observation module, which is arranged on the side of the Z-axis sliding module and is used to observe whether the needle tip of the printing needle is damaged.

[0019] Furthermore, the system also includes an X-axis sliding module and a Y-axis sliding module for controlling the movement of the capacitive sensor.

[0020] Furthermore, the position measurement module is arranged on a side of the Z-axis sliding module.

[0021] Furthermore, the printing needle includes but is not limited to a glass needle, and is also applicable to printing needles with a smaller limit stress value. The 3D printing contact needle alignment system of the present invention is particularly suitable for slender glass needle alignment, wherein the diameter of the glass needle is 18-50 μm and the needle tip length is not less than 100 mm.

[0022] In a second aspect, the present invention provides a 3D printing device, which includes the above-mentioned 3D printing contact needle alignment system.

[0023] Furthermore, the device also includes a printing platform, and the printing platform can be controlled to move by an X-axis sliding module and a Y-axis sliding module.

[0024] Furthermore, the position measurement module can be used to measure its relative position with the capacitive sensor, and can also be used to measure its relative position with the printing platform.

[0025] Furthermore, the device also includes a stabilizing block and a wind shield for achieving higher precision needle alignment; it can also be used in conjunction with a corresponding software system for automated needle alignment.

[0026] In a third aspect, the present invention provides a 3D printing contact type needle alignment method, the method comprising:

[0027] Move the capacitive sensor to the bottom of the position measurement module, and measure the distance from the contact sensing surface of the capacitive sensor to the position measurement module as Z1;

[0028] Move the printing platform to the bottom of the position measurement module, and measure the relative position of the position measurement module to the printing platform as Z2. At this time, the absolute position of the printing platform is set to Z0, and the absolute position of the capacitive sensor is Z3 = Z0 + Z2 - Z1.

[0029] Move the contact sensing surface of the capacitive sensor to the bottom of the print head, slowly lower the Z-axis sliding module, and when the capacitive sensor displays a reading (that is, after the print needle contacts the contact sensing surface), capture the Z-axis sliding module position Z4, obtain the absolute position of the glass needle Z5 = Z4-Z3, and then lift the Z-axis sliding module.

[0030] Furthermore, after the position measurement module completes the measurement of the contact surface distance of the capacitive sensor, the contact sensing surface of the capacitive sensor is moved to the bottom of the print head, and the Z-axis sliding module is manually lowered. The visual observation module is first used to preliminarily determine whether the glass needle is in contact with the contact sensing surface of the capacitive sensor. When the two are close, the descending speed of the Z-axis sliding module is reduced until the print needle contacts the contact sensing surface and generates a contact signal.

[0031] The 3D printing contact needle alignment system, 3D printing device and needle alignment method provided by the present invention have the following beneficial effects:

[0032] The capacitive sensor uses the temperature change of the internal coil to determine whether the printing needle is in contact with the capacitive sensor, thereby achieving high-precision needle alignment. When the capacitive sensor comes into contact with the needle tip, the relative position of the sensor contact sensing surface is changed due to hard contact, the internal resistance is reduced, and the current passing through the internal part increases, thereby determining whether the needle tip has reached the relative position. The sensor can capture a position of 1μm, and after the needle tip contacts the sensor and then drops 10μm, the needle tip is still intact, and the extreme position can reach 15μm. The needle alignment accuracy of the needle alignment system of the present invention can reach at least 1μm. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a structural schematic diagram of the 3D printing contact needle alignment system;

[0034] Figure 2 It is a structural schematic diagram of a 3D printing device;

[0035] Figure 3 Schematic diagram of the internal structure of a capacitive sensor.

[0036] Explanation of the accompanying drawings: 1. Position measurement module, 2. Z-axis sliding module, 3. Visual observation module, 4. Print head, 5. Capacitive sensor, 6. X-axis sliding module, 7. Y-axis sliding module, 8. Printing platform, 9. Temperature sensor, 10. Current controller, 11. Electro-optical position sensor, 12. Support rod, 13. Sensing axis point, 14. Contact sensing surface, 15. Coil. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0038] Example

[0039] like Figure 1 As shown, the 3D printing contact needle alignment system of the present invention includes an X-axis sliding module 6, a Y-axis sliding module 7, a Z-axis sliding module 2, a position measurement module 1, a print head 4, a capacitive sensor 5 and a visual observation module 3;

[0040] The X-axis sliding module 6 and the Y-axis sliding module 7 are used to control the movement of the capacitive sensor 5;

[0041] The Z-axis sliding module 2 is arranged above the print head 4 and is used to control the up and down movement of the print head 4. A printing needle is arranged below the print head 4.

[0042] The position measurement module 1 is arranged on the side of the Z-axis sliding module 2, and is used to measure the relative positions of various components; specifically, a laser rangefinder can be used as the position measurement module 1;

[0043] The visual observation module 3 is arranged on the side of the Z-axis sliding module 2, and the visual observation module 3 can observe in real time whether the tip of the printing needle is damaged; specifically, a tilt camera can be used as the visual observation module 3;

[0044] The capacitive sensor 5 uses the temperature change caused by the current in the internal coil 15 to determine whether the printing needle is in contact with the capacitive sensor 5, thereby achieving high-precision needle alignment;

[0045] The printing needle is a glass needle. The 3D printing contact needle alignment system of the present invention is particularly suitable for slender glass needle alignment. The diameter (outer diameter) of the glass needle used in this embodiment is 29 μm and the needle tip length is 100 mm.

[0046] like Figure 3 As shown, the capacitive sensor 5 includes a contact sensing surface 14, a temperature sensor 9, a current controller 10, an electro-optical position sensor 11, a support rod 12, a sensing axis point 13 and a coil 15;

[0047] The contact sensing surface 14 is arranged above the support rod 12 for contacting with the printing needle, and a sensing axis point 13 is arranged below the support rod 12;

[0048] The photoelectric position sensor 11 is used to detect the change in the relative position of the support rod 12 and control the current controller 10 to regulate the current, and the temperature of the resistance of the coil 15 changes accordingly;

[0049] The temperature sensor 9 is used to detect the temperature change of the resistance of the coil 15 .

[0050] The working principle of the capacitive sensor 5 is as follows: when an object contacts the contact sensing surface 14 of the capacitive sensor 5, the object's own gravity will cause the support rod 12 connected to the contact sensing surface 14 inside the capacitive sensor 5 to tilt, and after the electro-optical position sensor 11 detects the position change information of the support rod 12, it controls to increase the current flowing through the compensation coil 15, and under the support of the sensing axis point 13, the support rod 12 returns to the original equilibrium position; the coil 15 is located in the permanent magnet, and the change of the current in the coil 15 will bring about a change in the magnetic flux and then a change in temperature. Finally, the object-related information is obtained by reversely detecting the temperature change, and the reading is displayed on the capacitive sensor 5.

[0051] Exemplarily, the reading displayed by the capacitive sensor 5 can be the mass of the object. The capacitive sensor 5 can reflect the milligram-level gravity change of the object. When the contact sensing surface 14 is not in contact with the glass needle tip, the reading is 0. After the contact sensing surface 14 is in contact with the glass needle tip, a real-time reading is displayed.

[0052] like Figure 2 As shown, the present invention also provides a 3D printing device, which includes the above-mentioned 3D printing contact needle alignment system and a printing platform 8, and the printing platform 8 can be controlled to move by an X-axis sliding module 6 and a Y-axis sliding module 7; in addition, the device can also include a stabilizing block and a windshield to achieve higher precision needle alignment; it can also cooperate with a corresponding software system for automated needle alignment.

[0053] The method for performing 3D printing contact type needle alignment using the above device comprises the following steps:

[0054] (1) When the needle alignment starts, the capacitive sensor 5 is moved to the bottom of the position measurement module 1 by controlling the X-axis sliding module 6 and the Y-axis sliding module 7, and the distance from the contact sensing surface 14 of the capacitive sensor 5 to the position measurement module 1 is measured as Z1;

[0055] (2) Move the X-axis sliding module 6 and the Y-axis sliding module 7 again, move the printing platform 8 to the bottom of the position measurement module 1, and measure the relative position of the position measurement module 1 to the printing platform 8 as Z2. At this time, the absolute position of the printing platform 8 is set to Z0, and the absolute position of the capacitive sensor 5 is Z3=Z0+Z2-Z1;

[0056] (3) After the position measurement module 1 completes the distance measurement between the contact sensing surface 14 of the capacitive sensor 5, the X-axis sliding module 6 and the Y-axis sliding module 7 are continued to be moved to move the capacitive sensor 5 to the bottom of the print head 4, and the Z-axis sliding module 2 is slowly lowered. When the capacitive sensor 5 displays a reading (that is, after the print needle contacts the contact sensing surface 14), the position Z4 of the Z-axis sliding module 2 (the position of the guide rail inside the Z-axis sliding module) is captured to obtain the absolute position Z5 of the glass needle = Z4-Z3, and then the Z-axis sliding module 2 is lifted.

[0057] In this needle alignment process, the descending mode and speed of the Z-axis sliding module 2 are important factors affecting the needle alignment accuracy, and a manual needle alignment method is preferably used. Specifically, step (3) includes: after completing the distance measurement of the contact sensing surface 14 of the capacitive sensor 5 by the position measurement module 1, continue to move the X-axis sliding module 6 and the Y-axis sliding module 7, move the capacitive sensor 5 to the bottom of the print head 4, and manually slowly lower the Z-axis sliding module 2. First, use the visual observation module 3 to preliminarily determine whether the glass needle is in contact with the contact sensing surface 14 of the capacitive sensor 5. When the visual observation module 3 observes that the two are close, reduce the descending speed of the Z-axis sliding module 2, and slowly lower the needle at a rate of 1 μm each time until the print needle contacts the contact sensing surface 14 to generate a contact signal, capture the position Z4 of the Z-axis sliding module 2, and then lift the Z-axis sliding module 2.

[0058] In addition, the above-mentioned needle alignment process can also adopt a software automated needle alignment method. Specifically, step (3) includes: connecting the capacitive sensor 5 to the 485 signal module, and during the needle alignment process, after completing the distance measurement of the contact sensing surface 14 of the capacitive sensor 5 by the position measurement module 1, continue to move the X-axis sliding module 6 and the Y-axis sliding module 7, move the capacitive sensor 5 to the bottom of the print head 4, and the Z-axis sliding module 2 automatically descends from fast to slow. The software controls the descending speed of the Z-axis sliding module 2 to slowly lower the needle; after the contact is generated, the capacitive sensor 5 sends a signal to the 485 signal module, which is transmitted to the motor of the Z-axis sliding module 2 through the industrial computer to complete the lifting of the Z-axis sliding module 2. The height of the Z-axis sliding module 2 when the signal is generated is the needle alignment height.

[0059] When verifying the process needle solution, corresponding tests were conducted on the limit breakage value of the glass needle.

[0060] The glass needle is fixed on the Z-axis sliding module 2, touching the capacitive contact sensor, and measuring the correlation between the descending distance of the Z-axis sliding module 2 and the breakage of the glass needle. The relative height of the Z-axis sliding module 2 when the capacitive sensor 5 reads the contact signal of the glass needle for the first time is Z6 (by comparison, the relative height Z6 position and the absolute position error range is less than or equal to 2μm), and it continues to descend 1μm each time. The visual observation module 3 is used to observe the change of the needle tip. There is no obvious change in the needle tip at 0-10μm, and about 95% of the needle tips have no obvious change at 11-15μm. When it is greater than 15μm, the needle tip changes significantly and some of them have been broken.

[0061] Repeatability verification: At the same point, the needle alignment was repeated many times. There was no obvious fluctuation in the initial trigger value, and the initial trigger value changed by 1μm, which met the needle alignment requirements.

[0062] Difference verification: Needle alignment is repeated multiple times at different points, and the range of different positions is 0.0015, which meets the needle alignment requirements.

[0063] Comparative Example 1

[0064] Based on Example 1, the capacitive sensor is replaced by an industrial pressure tool setting instrument.

[0065] The working principle of the industrial pressure tool setting instrument is to obtain the needle tip position signal based on the relative position change of the grating scale caused by the pressure change. Specifically, when pressure is applied to the industrial pressure tool setting instrument, the relative position of the grating scale also changes synchronously, and then the electrical signal is read by judging the relative displacement of the grating scale to capture the needle tip position.

[0066] During use, the trigger pressure threshold of the grating scale of the tool setting instrument is about 0.3N. Since the ceramic needle has good stability and the maximum stress of the needle tip being broken is large, it can be used as a module to capture the position of the ceramic needle tip. However, when using the glass needle, the glass needle has not reached the trigger threshold and has been broken, so it cannot be used as a needle setting module.

[0067] Comparative Example 2

[0068] Based on Example 1, the capacitive sensor is replaced by a light-transmitting laser detection sensor.

[0069] The working principle of the light transmission type laser detection sensor is: a laser light curtain is formed by using a laser transmitter and a laser receiver. The needle tip passes through the laser light curtain, blocking part of the laser, and changing the amount of light passing through to determine whether the needle tip has reached the specified position. Specifically, using a transmission lens, the laser light emitted in the form of a parallel beam will converge on the light receiving element (high sensitivity PD) after passing through the light receiving lens. When the measured target blocks this parallel beam, the beam will be reduced in proportion to the amount of light blocked and incident on the light receiving element. At this time, capturing the amount of light in the light receiving element (high sensitivity PD) can measure the size and transparency of the target.

[0070] Since the ceramic needle is opaque, the position of the needle tip can be captured when it initially enters the light curtain, but it also has the problem of not being able to trigger the reading immediately after contacting the laser beam. For glass needles, due to their inherent transparency, the position of the needle tip cannot be captured when passing through the laser light curtain. Therefore, the above-mentioned light transmission type laser detection sensor cannot provide a solution for high-precision alignment of glass needles.

[0071] Comparative Example 3

[0072] Based on Example 1, the capacitive sensor is replaced by a high-precision contact digital sensor (GT2 series).

[0073] The high-precision contact digital sensor uses an industrial probe as a spring pressure sensor, and its working principle is: after the object to be tested touches the probe head and reaches the trigger threshold (measuring force), a micro displacement is generated within the detection and measurement range, and whether the glass needle tip is in contact with the sensor is judged based on the displacement reading; specifically, a CMOS sensor is used for high-speed shooting, and its movement is read from a grating scale pulse system II engraved with a slit pattern that varies with position.

[0074] The test result is: the glass needle has been broken when the electrical signal is generated and the reading feedback appears, so the sensor cannot be used as a needle alignment module.

[0075] Comparative Example 4

[0076] Based on Example 1, the capacitive sensor is replaced by a bridge strain gauge.

[0077] The working principle of the bridge strain gauge is: when the conductor or semiconductor material is mechanically deformed under the action of external force, its resistance value changes accordingly. The change in resistance value is used to determine whether the glass needle tip is in contact with the sensor. Specifically, the strain gauge is attached to the glass, the glass needle tip contacts the strain gauge, and the metal foil inside bends with the strain, and its resistance changes when it bends. Whether the needle tip is in contact is determined by capturing the change in current.

[0078] The test results showed that the strain gauge trigger threshold was too large, the strain gauge resistance did not change significantly after contact, and the glass needle tip was too thin to bend the bridge strain gauge and could not be used as a needle alignment module.

[0079] Comparing the above embodiments, comparative examples 1, 2, 3 and 4, it can be seen that compared with the prior art, the 3D printing contact needle alignment system provided by the present invention can effectively utilize the temperature change of the internal coil of the capacitive sensor to determine whether the printing needle head is in contact with the capacitive sensor, thereby achieving high-precision needle alignment. When the capacitive sensor comes into contact with the needle tip, the relative position of the sensor contact sensing surface is changed by hard contact, the internal resistance is reduced, and the current passing through the internal part is increased, thereby determining whether the needle tip has reached the relative position. The capacitive sensor can capture the position of 1μm, and after the needle tip contacts the sensor, it drops another 10μm, and the glass needle is still not damaged. The extreme position can reach 15μm (the integrity rate of the glass needle is about 95%), and the needle alignment accuracy can reach at least 1μm. This is a needle alignment accuracy that cannot be achieved by the prior art (including industrial pressure tool setting instruments, light transmission laser detection sensors, high-precision contact digital sensors, and bridge strain gauges, etc.), and the technical effect of the present invention is significant.

[0080] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0081] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0082] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the present invention.

Claims

1. A 3D printing contact needle alignment system, characterized in that: Includes Z-axis slide module, position measurement module, print head and capacitive sensor; The Z-axis sliding module is arranged above the print head and is used to control the up and down movement of the print head. A printing needle is arranged below the print head. The position measurement module is used to measure the relative positions of various components; The capacitive sensor uses the temperature change caused by the internal coil current to determine whether the printing needle is in contact with the capacitive sensor, thereby achieving needle alignment.

2. The 3D printing contact needle alignment system according to claim 1, characterized in that: The capacitive sensor includes a contact sensing surface, a temperature sensor, a current controller, an electro-optical position sensor, a support rod, a sensing axis point and a coil; The contact sensing surface is arranged above the support rod for contacting with the printing needle, and a sensing axis point is arranged below the support rod; The photoelectric position sensor is used to detect the change of the relative position of the support rod and control the current controller to regulate the current, and the temperature of the coil resistance changes accordingly; The temperature sensor is used to detect the temperature change of the coil resistance.

3. The 3D printing contact needle alignment system according to claim 1, characterized in that: The system also includes a visual observation module, which is arranged on the side of the Z-axis sliding module and is used to observe whether the needle tip of the printing needle is damaged.

4. The 3D printing contact needle alignment system according to claim 1, characterized in that: The system also includes an X-axis sliding module and a Y-axis sliding module for controlling the movement of the capacitive sensor.

5. The 3D printing contact needle alignment system according to claim 1, characterized in that: The position measurement module is arranged on the side of the Z-axis sliding module.

6. A 3D printing device, characterized in that: It comprises the 3D printing contact needle alignment system as described in any one of claims 1-5.

7. The 3D printing device according to claim 6, characterized in that: The device also includes a printing platform, and the printing platform can be controlled to move by an X-axis sliding module and a Y-axis sliding module.

8. The 3D printing device according to claim 6, characterized in that: The device also includes a stabilizer block and a wind shield.

9. A 3D printing contact needle alignment method, characterized in that: The 3D printing device according to any one of claims 6 to 8 is used to align needles, the method comprising: Move the capacitive sensor to the bottom of the position measurement module, and measure the distance from the contact sensing surface of the capacitive sensor to the position measurement module as Z1; Move the printing platform to the bottom of the position measurement module, and measure the relative position of the position measurement module to the printing platform as Z2. At this time, the absolute position of the printing platform is set to Z0, and the absolute position of the capacitive sensor is obtained as Z3=Z0+Z2-Z1; Move the contact sensing surface of the capacitive sensor to the bottom of the print head, lower the Z-axis slide module, and when the capacitive sensor displays a reading, capture the Z-axis slide module position Z4 to obtain the absolute position Z5 = Z4-Z3 of the print needle, then lift the Z-axis slide module to complete the needle alignment.

10. The 3D printing contact type needle alignment method according to claim 9, characterized in that: First, the visual observation module is used to preliminarily determine whether the glass needle is in contact with the contact sensing surface of the capacitive sensor. When the two are close, the descending speed of the Z-axis sliding module is reduced until the printing needle contacts the contact sensing surface and generates a contact signal.

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