An electrohydrodynamic jet printing apparatus and method with break detection

Abstract

The application discloses a kind of electrohydrodynamic jet printing device and method with breakpoint detection function, adopt according to the way of judging defect of reflected ultrasonic wave direction, compared with other ways have many advantages such as high identification precision, fast printing speed, non-contact measurement, economic benefit etc..In the process of very fine jet printing, ultrasonic generator continuously sends high-frequency mechanical signal as signal source, high-frequency mechanical signal occurs total reflection after contacting very fine jet, and the direction of reflected high-frequency mechanical signal is related to the form of very fine jet.Reflected high-frequency mechanical signal points to piezoelectric ceramic array, and the piezoelectric ceramic sheet receiving reflected high-frequency mechanical signal will produce piezoelectric effect, generate regular electric signal, identify the position of electric signal and calculate, and the form of very fine jet can be obtained.The application has the characteristics of real-time detection and wide ink adaptability by introducing breakpoint detection mechanism, and can realize high-precision very fine jet form detection.

Description

Technical Field

[0001] This invention relates to the field of advanced manufacturing technology, and specifically to a current-powered jet printing device and method with a breakpoint detection function. Background Technology

[0002] With the development of 3D printing technology, ultra-fine jet printing is gradually being applied to many high-precision industries such as medical, photovoltaic, and aerospace. Electrohydrodynamic jet printing, proposed and developed by Park and Rogers et al., is a microdroplet jetting deposition technology based on electrohydrodynamics (EHD). It is a common method for preparing ultra-fine jets. Unlike traditional inkjet printing, which uses a "push" method, EHD printing uses an electric field to drive and "pull" the ultra-fine jet from the tip of a Taylor cone. During electrohydrodynamic jet printing, depending on different process parameters, it can be divided into three different printing modes: electrospraying, electrospinning, and electrocoating. By studying the dynamic behavior of electrostatically induced fluid flowing out of capillary nozzles to form jets, submicron resolution patterns can be printed. Spraying produces very uniform droplets under medium to low voltage and low flow rate supply. Electrospinning, under low voltage and high flow rate supply, forms a continuous jet of ejected ink, which is deposited in a fibrous form on the collecting substrate. Electro-spraying, on the other hand, uses an electric field to atomize droplets under high pressure and medium-low flow rate, and then deposits them onto a collecting substrate. Regardless of the type of electro-hydraulic jet printing technology, it is affected by many factors, and printing defects are prone to occur when printing extremely fine jets. The quality stability of such products needs to be improved.

[0003] Currently, most methods for identifying such defects rely on manual identification and post-processing experimental measurement, which is not only inefficient but also lacks real-time capability, making timely remediation impossible. Visual identification of breakpoints is a common approach, as described in "Rapid Determination Method for Broken Filaments in 3D Printing" (CN201911375851.3) and "3D Array Inkjet Printing Defect Detection and Correction System and Method" (CN202110512321.X). However, due to limited equipment resolution, high equipment costs, and the extremely small scale of the jets, visual sensors cannot accurately capture the graphic data of the extremely fine jets, thus failing to achieve effective detection. Recently, some AI-based visual defect identification methods have emerged, such as "A Deep Learning-Based 3D Printing Defect Detection Method Based on an Improved Yolox Algorithm" (CN202310959756.8). However, the method of AI autonomously intervening and correcting errors during the printing process lacks mature theoretical support, and the identification speed is slow, unable to keep pace with the printing speed. The first step requires waiting for recognition, which seriously affects the printing speed. Due to the small size of the ultrafine jet, the motion path to complete the printing of the whole plate is long, so using this method will greatly increase the processing time. Ultrasonic waves also have some applications in defect detection, but they are all based on the amplitude and frequency characteristics and image frequency characteristics of sound waves. For example, the ultrasonic non-destructive testing method, device and system based on digital twin equipment (CN202210877027.3) and the defect detection method of 3D printing material for marine parts based on ultrasonic technology ([J]. Ship Science and Technology, 2022, 44(18):69-72) are described. Their devices are large in size and need to be measured on the surface of the object being tested. However, the ultrafine jet needs a certain amount of time to solidify, and the surface of the object being tested cannot be touched in a short time. Moreover, due to the small size of the ultrafine jet, it is not easy to achieve contact with the sensor, so it is not applicable. The above methods have problems such as insufficient resolution, reduced printing speed, need for contact measurement, and expensive equipment for jets with small size. Summary of the Invention

[0004] To address the aforementioned technical problems and shortcomings in the field, this invention provides an electrohydrodynamic jet printing device and method with a breakpoint detection function, which can promptly detect defects in extremely fine jets and prevent safety accidents.

[0005] This invention uses the method of judging defects based on the direction of reflected ultrasonic waves, which has many advantages over other methods, such as high recognition accuracy, fast printing speed, non-contact measurement, and high economic benefits.

[0006] In the ultrafine jet printing process, an ultrasonic generator continuously emits high-frequency mechanical signals as the signal source. These high-frequency mechanical signals undergo total internal reflection upon contact with the ultrafine jet, and the direction of the reflected high-frequency mechanical signals is related to the shape of the ultrafine jet. The reflected high-frequency mechanical signals point towards the piezoelectric ceramic array. The piezoelectric ceramic sheets that receive the reflected high-frequency mechanical signals will exhibit a piezoelectric effect, generating regular electrical signals. By identifying the location where the electrical signals are generated and calculating them, the shape of the ultrafine jet can be obtained.

[0007] This invention introduces a breakpoint detection mechanism, which features real-time detection and wide ink adaptability, enabling high-precision detection of extremely fine jet morphology.

[0008] A hydrodynamic jet printing device with breakpoint detection function includes a hydrodynamic jet module and a breakpoint detection module;

[0009] The electrohydrodynamic jetting module includes a printing substrate and a precision injection device, a solution conduit, a nozzle, and an ultrafine jet nozzle connected in sequence. There is an electric field force between the ultrafine jet nozzle and the printing substrate. The precision injection device contains a printing jet solution. Under the action of the precision injection device, the printing jet solution is transported to the ultrafine jet nozzle through the solution conduit and the nozzle, and finally forms an ultrafine jet on the printing substrate under the action of a variety of mixed forces, including electric field force, gravity, and viscosity.

[0010] The breakpoint detection module includes an arc-shaped support located behind the ultrafine jet nozzle in the direction of advancement relative to the printing substrate, which can move together with the ultrafine jet nozzle relative to the printing substrate along the ultrafine jet direction. The center of the arc-shaped support coincides with the center line of the ultrafine jet. An ultrasonic generator that continuously emits high-frequency mechanical signals toward the ultrafine jet located at the center of the arc-shaped support is eccentrically installed on the inner side of the arc-shaped support. The ultrafine jet can reflect the high-frequency mechanical signals. The remaining positions on the inner side of the arc-shaped support are filled with piezoelectric ceramics that can receive the high-frequency mechanical signals reflected by the ultrafine jet and convert them into electrical signals.

[0011] In one embodiment, the electrohydrodynamic jet printing device with breakpoint detection function includes a precision injection device comprising a precision injection pump and a precision syringe fixed above the precision injection pump. The precision syringe is connected to a solution conduit and contains a printing jet solution.

[0012] In one embodiment, the electrohydrodynamic jet printing device with breakpoint detection function has a printing substrate fixed on an XY motion platform, which is used to control the movement of the printing substrate in the X and Y axes that are perpendicular to each other on a horizontal plane.

[0013] In one embodiment, the electrohydrodynamic jet printing device with breakpoint detection function has an ultrafine jet nozzle connected to a high-voltage power supply via a conductive nozzle holder, and is at a high potential relative to the printing substrate.

[0014] In one embodiment, the electrohydrodynamic jet printing device with breakpoint detection function also includes a conductive nozzle holder for controlling the movement of the ultrafine jet nozzle in the Z-axis direction of the vertical horizontal plane.

[0015] In one embodiment, the electrohydrodynamic jet printing device with breakpoint detection function has an arc-shaped bracket fixedly connected to the printhead via a connecting rod.

[0016] The present invention also provides the application of the electrohydrodynamic jet printing device with breakpoint detection function in electrohydrodynamic jet printing and breakpoint detection.

[0017] The present invention also provides a current-vapor dynamic jet printing method with breakpoint detection function, using the aforementioned current-vapor dynamic jet printing device with breakpoint detection function;

[0018] The described electrohydrodynamic jet printing method with breakpoint detection function involves forming an extremely fine jet on a printing substrate under the action of multiple mixing forces. An ultrasonic generator continuously emits high-frequency mechanical signals as a signal source. The high-frequency mechanical signals are reflected on the surface of the extremely fine jet to the piezoelectric ceramic, where the piezoelectric effect occurs. This process converts the jet morphology information into an electrical signal, and the specific jet morphology is obtained through data processing.

[0019] If the piezoelectric ceramic on the arc-shaped support, located at the axisymmetric position of the ultrasonic generator, exhibits a piezoelectric effect when printed to a certain point on the printing substrate, it indicates that the ultrafine jet breaks at that printing location.

[0020] In one embodiment, the electro-hydraulic jet printing method with breakpoint detection function specifically includes:

[0021] 1) Printing extremely fine jets:

[0022] Under the action of the precision injection device, the printing jet solution is transported to the ultra-fine jet nozzle through the solution conduit and nozzle, and finally forms an ultra-fine jet on the printing substrate under the action of a variety of mixed forces including electric field force, gravity and viscosity.

[0023] 2) High-frequency mechanical signal transmission:

[0024] The ultrasonic generator continuously sends incident high-frequency mechanical signals toward the ultrafine jet located at the center of the arc-shaped support. When the incident high-frequency mechanical signals pass through the surface of the ultrafine jet, they are reflected, thus obtaining a reflected high-frequency mechanical signal whose direction is related to the curvature of the ultrafine jet surface.

[0025] 3) Signal conversion and processing:

[0026] The reflected high-frequency mechanical signal is propagated in a straight line to a piezoelectric ceramic. The piezoelectric ceramic undergoes the piezoelectric effect, converting the reflected high-frequency mechanical signal into a high-frequency alternating current. The coordinates of the piezoelectric ceramic that receives the reflected high-frequency mechanical signal are then obtained, and the shape of the reflection point on the surface of the ultrafine jet is calculated accordingly.

[0027] Compared with the prior art, the beneficial effects of this invention are as follows:

[0028] This invention provides an electro-hydraulic jet printing device and method with a breakpoint detection function, which can promptly detect defects in extremely fine jets and prevent safety accidents.

[0029] This invention uses the method of judging defects based on the direction of reflected ultrasonic waves, which has many advantages over other methods, such as high recognition accuracy, fast printing speed, non-contact measurement, and high economic benefits.

[0030] This invention introduces a breakpoint detection mechanism, which features real-time detection and wide ink adaptability, enabling high-precision detection of extremely fine jet morphology. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the electro-hydraulic jet printing device with breakpoint detection function in the embodiment;

[0032] Figure 2 This is a schematic diagram of the breakpoint detection module in the embodiment;

[0033] Figure 3 This is a schematic diagram of signal transmission in the embodiment. Detailed Implementation

[0034] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0035] See Figure 1 The electro-hydraulic jet printing device with breakpoint detection function in this embodiment includes an electro-hydraulic jet module and a breakpoint detection module.

[0036] The electrohydrodynamic jetting module includes a printing substrate 12 and a precision injection device, a solution conduit 4, a nozzle 11, and an ultrafine jet nozzle 6 connected in sequence. The diameter of the ultrafine jet nozzle 6 can be 5–200 μm.

[0037] The printing substrate 12 is fixed on the XY motion platform 13, which controls the movement of the printing substrate 12 along the mutually perpendicular X and Y axes on a horizontal plane. The XY motion platform 13 can be a multi-axis lead screw module with a positioning accuracy of ±0.05mm, and can be controlled by a servo motor with a step size of 0.1mm, with a movement range of 200mm×200mm. The thickness of the printing substrate 12 can be 0.4~100μm, and the printing substrate 12 can be a conductor, semiconductor, or insulator material.

[0038] The precision injection device includes a precision injection pump 1 and a precision syringe 2 fixed above the precision injection pump 1. The precision syringe 2 is connected to a solution conduit 4 and contains a printing jet solution 3. The precision injection pump 1 can be an HC-G30 industrial injection pump, capable of 0.005mm step movement, using a lead screw drive, and is corrosion-resistant and high-temperature resistant, suitable for various printing jet solutions 3. The printing jet solution 3 can use various conductive pastes containing metal particles. The volume range of the precision syringe 2 can be 25–300 μL.

[0039] The ultra-fine jet nozzle 6 is connected to the high-voltage power supply 5 via the conductive nozzle holder 10 and is at a high potential relative to the printing substrate 12. The printing substrate 12 is grounded and at a low potential. There is an electric field between the ultra-fine jet nozzle 6 and the printing substrate 12. The high-voltage power supply 5 can generate a voltage of 200-2000V, with a maximum power of 600W, and the output voltage is continuously adjustable.

[0040] The conductive nozzle clamp 10 is also used to control the movement of the ultrafine jet nozzle 6 in the Z-axis direction of the vertical horizontal plane, and the movement range can be 0 to 50 mm.

[0041] After a certain volume of printing jet solution 3 is drawn from the precision syringe 2, the precision injection pump 1 applies pressure to deliver the printing jet solution 3 in the precision syringe 2 through the solution conduit 4 and the nozzle 11 to the ultrafine jet nozzle 6. The printing jet solution 3 is finally formed into an ultrafine jet 9 on the printing substrate 12 under the action of a variety of mixed forces, including electric field force, gravity and viscosity.

[0042] Combination Figure 1 , Figure 2The breakpoint detection module includes an arc-shaped support 8 located behind the ultrafine jet nozzle 6 relative to the printing substrate 12 in the forward direction and movable along the ultrafine jet 9 direction with the ultrafine jet nozzle 6 relative to the printing substrate 12. The circumferential radius of the arc-shaped support 8 can be 12mm, and the thickness of the arc-shaped support 8 can be 3mm. The arc-shaped support 8 is fixedly connected to the nozzle 11 via a connecting rod 7. The center of the arc-shaped support 8 coincides with the center line of the ultrafine jet 9. An ultrasonic generator 14 is eccentrically mounted inside the arc-shaped support 8, which continuously emits high-frequency mechanical signals toward the ultrafine jet 9 located at the center of the arc-shaped support 8. The ultrasonic generator 14 can generate sinusoidal mechanical waves with a frequency of 20000-40000Hz and an amplitude of 40-80μm. The ultrafine jet 9 can reflect the high-frequency mechanical signals. The remaining positions inside the arc-shaped support 8 are filled with piezoelectric ceramics 15 that can receive the high-frequency mechanical signals reflected by the ultrafine jet 9 and convert them into electrical signals. The piezoelectric ceramic 15 can be a square structure with a thickness of 0.2 mm and an area of ​​3 mm × 1.9 mm, and the sensitive frequency range is 0.1-2 MHz.

[0043] The aforementioned electro-hydraulic jet printing device with breakpoint detection function can be used for electro-hydraulic jet printing and breakpoint detection.

[0044] Using the above-mentioned electro-hydraulic jet printing device with breakpoint detection function, an electro-hydraulic jet printing method with breakpoint detection function is performed. The printing jet solution 3 forms an ultrafine jet 9 on the printing substrate 12 under the action of multiple mixing forces. The ultrasonic generator 14 continuously emits high-frequency mechanical signals as a signal source. The high-frequency mechanical signals are reflected on the surface of the ultrafine jet 9 to the piezoelectric ceramic 15, and the piezoelectric effect occurs in the piezoelectric ceramic 15, thereby realizing the process of converting jet morphology information into electrical signals. The specific jet morphology is obtained through data processing.

[0045] If the piezoelectric ceramic 15 on the arc-shaped support 8, located at the axisymmetric position of the ultrasonic generator 14, exhibits a piezoelectric effect when printed to a certain point on the printing substrate 12, it indicates that the ultrafine jet 9 has a break at that printing position.

[0046] Combination Figures 1 to 3 The aforementioned electro-hydraulic jet printing method with breakpoint detection function specifically includes:

[0047] 1) Printing ultra-fine jets 9:

[0048] Under the action of the precision injection device, the printing jet solution 3 is transported to the ultra-fine jet nozzle 6 through the solution conduit 4 and the nozzle 11, and finally forms an ultra-fine jet 9 on the printing substrate 12 under the action of a variety of mixed forces including electric field force, gravity and viscosity.

[0049] 2) High-frequency mechanical signal transmission:

[0050] The ultrasonic generator 14 continuously sends incident high-frequency mechanical signals 16 toward the ultrafine jet 9 located at the center of the arc-shaped support 8. When the incident high-frequency mechanical signals 16 pass through the surface of the ultrafine jet 9, they are reflected, thereby obtaining a reflected high-frequency mechanical signal 17 whose direction is related to the curvature of the surface of the ultrafine jet 9.

[0051] 3) Signal conversion and processing:

[0052] The reflected high-frequency mechanical signal 17 is propagated in a straight line to a certain piezoelectric ceramic 15. The piezoelectric ceramic 15 exhibits the piezoelectric effect, converting the reflected high-frequency mechanical signal 17 into a high-frequency alternating current. The coordinates of the piezoelectric ceramic 15 that receives the reflected high-frequency mechanical signal 17 are then obtained, and the shape of the reflection point on the surface of the ultrafine jet 9 is calculated accordingly.

[0053] exist Figure 3 In the middle, the ultrasonic generator 14 is fixed to the left of the center of the inner side of the arc-shaped bracket 8. Taking the center point of the ultrafine jet 9 as the origin, the horizontal direction to the right is the X-axis, and the vertical direction upward is the Y-axis. The shape of the reflection point on the surface of the ultrafine jet 9 can be represented by the angle θ between its tangent and the X-axis. The specific calculation formula is as follows:

[0054] (x1, y1) lies in the first quadrant.

[0055] (x1, y1) is located in the second quadrant.

[0056] Where (x1, y1) represent the X-axis and Y-axis coordinates of the piezoelectric ceramic that exhibits the piezoelectric effect, and (x0, y0) represent the X-axis and Y-axis coordinates of the ultrasonic generator 14.

[0057] Furthermore, it should be understood that after reading the above description of the present invention, those skilled in the art can make various alterations or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A current-driven jet printing device with breakpoint detection function, characterized in that, Includes an electro-hydraulic power injection module and a breakpoint detection module; The electrohydrodynamic jetting module includes a printing substrate (12) and a precision injection device, a solution conduit (4), a nozzle (11), and an ultrafine jet nozzle (6) connected in sequence; there is an electric field force between the ultrafine jet nozzle (6) and the printing substrate (12); the precision injection device contains a printing jet solution (3); under the action of the precision injection device, the printing jet solution (3) is transported to the ultrafine jet nozzle (6) through the solution conduit (4) and the nozzle (11), and finally forms an ultrafine jet (9) on the printing substrate (12) under the action of a variety of mixed forces including electric field force, gravity and viscosity. The breakpoint detection module includes an arc-shaped support (8) located behind the ultrafine jet nozzle (6) in the forward direction relative to the printing substrate (12) and movable along the ultrafine jet (9) direction relative to the printing substrate (12). The center of the arc-shaped support (8) coincides with the center line of the ultrafine jet (9). An ultrasonic generator (14) is eccentrically installed on the inner side of the arc-shaped support (8) to continuously emit high-frequency mechanical signals toward the ultrafine jet (9) located at the center of the arc-shaped support (8). The ultrafine jet (9) can reflect the high-frequency mechanical signals. The remaining positions on the inner side of the arc-shaped support (8) are filled with piezoelectric ceramics (15) that can receive the high-frequency mechanical signals reflected by the ultrafine jet (9) and convert them into electrical signals.

2. The electro-hydraulic jet printing device with breakpoint detection function according to claim 1, characterized in that, The precision injection device includes a precision injection pump (1) and a precision syringe (2) fixed above the precision injection pump (1). The precision syringe (2) is connected to a solution conduit (4) and contains a printing jet solution (3).

3. The electrohydrodynamic jet printing device with breakpoint detection function according to claim 1, characterized in that, The printing substrate (12) is fixed on the XY motion platform (13), which is used to control the movement of the printing substrate (12) in the X and Y axes that are perpendicular to each other on the horizontal plane.

4. The electrohydrodynamic jet printing device with breakpoint detection function according to claim 1, characterized in that, The ultra-fine jet nozzle (6) is connected to the high-voltage power supply (5) via the conductive nozzle clamp (10) and is at a high potential relative to the printing substrate (12); The conductive nozzle clamp (10) is also used to control the movement of the ultrafine jet nozzle (6) in the Z-axis direction of the vertical horizontal plane.

5. The electro-hydraulic jet printing device with breakpoint detection function according to claim 1, characterized in that, The arc-shaped bracket (8) is fixedly connected to the nozzle (11) via the connecting rod (7).

6. The application of the electro-hydraulic jet printing device with breakpoint detection function according to any one of claims 1 to 5 in electro-hydraulic jet printing and breakpoint detection.

7. A hydrodynamic jet printing method with breakpoint detection function, characterized in that, The electrohydrodynamic jet printing device with breakpoint detection function as described in any one of claims 1 to 5 is used; The electrohydrodynamic jet printing method with breakpoint detection function describes a process where the printing jet solution (3) forms an ultrafine jet (9) on the printing substrate (12) under the action of multiple mixing forces. An ultrasonic generator (14) continuously emits high-frequency mechanical signals as a signal source. The high-frequency mechanical signals are reflected on the surface of the ultrafine jet (9) to the piezoelectric ceramic (15), where the piezoelectric effect occurs, thereby realizing the process of converting jet morphology information into electrical signals. The specific jet morphology is obtained through data processing. If the piezoelectric ceramic (15) on the arc support (8) located at the axisymmetric position of the ultrasonic generator (14) exhibits a piezoelectric effect when printed to a certain point on the printing substrate (12), it indicates that the ultrafine jet (9) has a break at that printing position.

8. The electro-hydraulic jet printing method with breakpoint detection function according to claim 7, characterized in that, The electro-hydraulic jet printing method with breakpoint detection function specifically includes: 1) Printing extremely fine jets (9): Under the action of the precision injection device, the printing jet solution (3) is transported to the ultrafine jet nozzle (6) through the solution conduit (4) and the nozzle (11), and finally forms an ultrafine jet (9) on the printing substrate (12) under the action of a variety of mixed forces including electric field force, gravity and viscosity. 2) High-frequency mechanical signal transmission: The ultrasonic generator (14) continuously sends incident high-frequency mechanical signals (16) to the ultrafine jet (9) located at the center of the arc-shaped support (8). The incident high-frequency mechanical signals (16) are reflected when they pass through the surface of the ultrafine jet (9), and thus a reflected high-frequency mechanical signal (17) with the direction related to the curvature of the surface of the ultrafine jet (9) is obtained. 3) Signal conversion and processing: The reflected high-frequency mechanical signal (17) is propagated in a straight line to a certain piezoelectric ceramic (15). The piezoelectric ceramic (15) undergoes the piezoelectric effect, converting the reflected high-frequency mechanical signal (17) into a high-frequency alternating current. The coordinates of the piezoelectric ceramic (15) that receives the reflected high-frequency mechanical signal (17) are then obtained, and the shape of the reflection point on the surface of the ultrafine jet (9) is calculated accordingly.

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