Device, method and system for measuring particle surface adhesion energy based on piezoelectric vibrator

Abstract

The present invention discloses a particle surface adhesion energy measurement device, method and system based on a piezoelectric vibrator. The device of the present invention comprises a housing, a detachable upper cover plate, a lower cover plate, a camera, a transparent glass plate, a piezoelectric vibrator, a horn, a fastening structure and a high-frequency signal generator, wherein the upper cover plate is located above the housing, the lower cover plate is fixed below the housing, the camera is placed above the lower cover plate, the transparent glass plate is fixed to a position above the camera in the housing, the piezoelectric vibrator and the horn are fixed above the transparent glass plate in the housing through a rotatable fastening structure, the horn is connected below the piezoelectric vibrator, and the high-frequency signal generator is connected to the piezoelectric vibrator through a lead. The present invention has high accuracy, a wide range of applications and a simple measurement process.

Description

Technical Field

[0001] The present invention relates to additive manufacturing technology, and in particular to a device, method and system for measuring particle surface adhesion energy based on a piezoelectric vibrator. Background Art

[0002] Particle surface adhesion energy testing is an important measurement method in the powder industry, which is used to quantitatively evaluate the adhesion strength of particles on various substrate surfaces. It has a wide range of applications in many fields, including additive manufacturing, pharmaceuticals, materials science, food industry, and nanotechnology. Particle adhesion performance directly affects the quality, stability, processing performance and final use of the product, so the measurement and understanding of particle adhesion energy is of great significance.

[0003] At present, the technical means for measuring the surface adhesion energy of particles include atomic force microscopy (AFM), electric field separation method, centrifugation method, and aerodynamic separation method. Each measurement method has its own unique mechanism, but due to the size, shape, roughness and even environmental conditions of the particles, the results measured using each technical means may be different, which requires multiple experiments to obtain more realistic data. The atomic force microscope (AFM) is complex to operate, requires high technical requirements and is expensive, and its measurement range is relatively limited, the measurement time is long and the efficiency is low. The electric field separation method is mainly applicable to charged particles, and the surface adhesion energy test effect of non-charged particles is not good. The electric field and humidity of the environment may also affect the experimental results. For particles with very strong adhesion, the centrifugal force may not be enough to make them detach from the surface, which limits the scope of application of this method. Secondly, high centrifugal force may cause particles to break or deform, thereby affecting the accuracy of the measurement results. The aerodynamic separation method measures the force required for particles to detach from the substrate surface based on the shear force exerted by the airflow. Although multiple particles can be measured at the same time, it requires accurate simulation and calculation of the flow field characteristics of the airflow, which is complex and requires strict experimental conditions. It can be seen that the existing measurement methods either have cumbersome and complicated measurement processes, or have too narrow scope of application, or their accuracy needs to be improved. Summary of the invention

[0004] In view of the problems existing in the prior art, the purpose of the present invention is to provide a particle surface adhesion energy measurement device, method and system based on a piezoelectric vibrator, which has high accuracy, wide application range and simple measurement process.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] A particle surface adhesion energy measuring device based on a piezoelectric vibrator comprises a shell, a detachable upper cover plate, a lower cover plate, a camera, a transparent glass plate, a piezoelectric vibrator, a horn, a fastening structure and a high-frequency signal generator, wherein the upper cover plate is located above the shell, the lower cover plate is fixed below the shell, the camera is placed above the lower cover plate, the transparent glass plate is fixed to a position above the camera in the shell, the piezoelectric vibrator and the horn are fixed above the transparent glass plate in the shell via a rotatable fastening structure, the horn is connected below the piezoelectric vibrator, and the high-frequency signal generator is connected to the piezoelectric vibrator via a lead.

[0007] Furthermore, the fastening structure is specifically a detachable and elastic fastening ring. Both sides of the fastening ring are provided with screw holes for installing screws to fix the piezoelectric vibrator and the horn.

[0008] Furthermore, the shell is provided with a plurality of first through holes, and the transparent glass plate is fixed in the shell through a plurality of cylindrical pins inserted through the first through holes.

[0009] Furthermore, the amplitude transformer is connected to the piezoelectric vibrator by welding.

[0010] Furthermore, the housing is provided with two second through holes, and the two ends of the fastening ring are rotatably inserted into the second through holes, so that the piezoelectric vibrator and the amplitude transformer are turned over when the fastening ring rotates.

[0011] Furthermore, the outer shell is a cylinder, and the transparent glass plate is a circular plate having a radius equal to that of the inner radius of the outer shell.

[0012] Furthermore, the camera is specifically a CCD camera.

[0013] A method for measuring particle surface adhesion energy based on a piezoelectric vibrator, the method is implemented based on the above device, and comprises the following steps:

[0014] Step 1: Open the upper cover, rotate the fastening structure until the lower surface of the horn faces upward, and scatter the particles on the lower surface of the horn;

[0015] Step 2: Slowly rotate the fastening structure until the lower surface of the horn faces downward, and cover the upper cover;

[0016] Step 3: Start the high-frequency signal generator to output a sinusoidal electrical signal with an amplitude of A and a frequency of f;

[0017] Step 4: After a period of time, turn off the high-frequency signal generator and use a camera to take a photo P1 of the particles falling on the transparent glass plate;

[0018] Step 5: Open the upper cover, slowly rotate the fastening structure until the lower surface of the horn faces upward, and take a photo P2 of the particles on the lower surface of the horn;

[0019] Step 6: Calculate the critical diameter d of the falling particles according to the following formula based on the particle photos taken;

[0020]

[0021] Where d is the diameter of the largest particle in particle photo P2, and d is the diameter of the smallest particle in particle photo P1;

[0022] Step 7: Calculate the maximum acceleration a of the piezoelectric vibrator based on the amplitude A and frequency f of the sinusoidal electrical signal MAX :

[0023] a MAX =-4kAπ 2 f 2

[0024] Where k is the amplitude amplifier magnification, is the initial phase;

[0025] Step 8: Based on the balance between the adhesion force and the vibration force when the particle is separated from the lower surface of the horn, the surface adhesion energy of the particle is calculated according to the following formula:

[0026]

[0027] Where ρ is the particle density and Г is the particle surface adhesion energy.

[0028] A particle surface adhesion energy measurement system based on a piezoelectric vibrator comprises the above-mentioned device and a computer device, wherein the computer device comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the following steps:

[0029] Step 1: Obtain a photo P1 of particles falling onto the transparent glass plate after the high-frequency signal generator is started, and take a photo P2 of particles on the lower surface of the horn (7);

[0030] Step 2: Calculate the critical diameter d of the falling particles according to the following formula based on the particle photos taken;

[0031]

[0032] Wherein, d1 is the diameter of the largest particle in the particle photo P2, and d2 is the diameter of the smallest particle in the particle photo P1;

[0033] Step 3: Calculate the maximum acceleration a of the piezoelectric vibrator (6) based on the amplitude A and frequency f of the sinusoidal electrical signal emitted by the high-frequency signal generator. MAX :

[0034] a MAX =-4kAπ 2 f 2

[0035] Where k is the magnification of the horn (7), is the initial phase;

[0036] Step 4: Based on the balance between the adhesion force and the vibration force when the particle is separated from the lower surface of the horn (7), the surface adhesion energy of the particle is calculated according to the following formula:

[0037]

[0038] Where ρ is the particle density and Г is the particle surface adhesion energy.

[0039] Compared with the prior art, the present invention has the following beneficial effects: the measuring device of the present invention utilizes a piezoelectric vibrator to generate a frequency vibration and utilizes a horn to amplify this mechanical behavior, so that particles larger than a critical diameter fall off, thereby being able to calculate the surface adhesion energy of the particles. The entire experimental process is highly controllable, highly simplified, and the experimental results are accurate and highly repeatable. A high-frequency signal generator is used as a signal source, so that the signal transmission is accurate and highly controllable. The device of the present invention is not limited to measuring dry powders, but can also measure wet and oily powders, and the measurement types and measurement ranges are very wide. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a schematic structural diagram of a particle surface adhesion energy measuring device based on a piezoelectric vibrator provided in an embodiment of the present invention;

[0041] Figure 2 It is a graph of particle drop under different conditions;

[0042] Figure 3 It is a schematic diagram of the amplitude and time function curve of the piezoelectric vibrator. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0044] Embodiment 1

[0045] The embodiment of the present invention provides a particle surface adhesion energy measurement device based on a piezoelectric vibrator, such as Figure 1As shown, it includes a housing 1, a detachable upper cover plate 2, a lower cover plate 3, a camera 4, a transparent glass plate 5, a piezoelectric vibrator 6, a horn 7, a fastening structure 8 and a high-frequency signal generator (not shown), wherein the upper cover plate 2 is located above the housing 1, the lower cover plate 3 is fixed below the housing 1, the camera 4 is specifically a CCD camera, which is placed above the lower cover plate 3, the transparent glass plate 5 is fixed to a position above the camera 4 in the housing 1, the piezoelectric vibrator 6 and the horn 7 are fixed above the transparent glass plate 5 in the housing 1 through a rotatable fastening structure 8, and the horn 7 is welded below the piezoelectric vibrator 6 to amplify the electrical signal received by the piezoelectric vibrator 6, so that the mechanical vibration displacement and speed of the particles are further amplified. The high-frequency signal generator is connected to the piezoelectric vibrator 6 through a lead wire, and is used to control the vibration of the piezoelectric vibrator 6 through the generated signal.

[0046] The shell 1 is a cylinder, and the transparent glass plate 5 is a circular plate having the same radius as the inner radius of the shell 1 .

[0047] The fastening structure 8 is specifically a removable elastic fastening ring, and screw holes are provided on both sides of the fastening ring for installing screws to fix the piezoelectric vibrator 6 and the horn 7. Two second through holes are provided on the housing 1, and the two ends of the fastening ring can be rotatably inserted into the second through holes, so that the piezoelectric vibrator 6 and the horn 7 are turned over when the fastening ring rotates.

[0048] The housing 1 is provided with a plurality of first through holes, and the transparent glass plate 5 is fixed in the housing 1 through a plurality of cylindrical pins 9 inserted through the first through holes. Figure 1 Four first through holes and two cylindrical pins 9 are shown.

[0049] Embodiment 2

[0050] The embodiment of the present invention provides a method for measuring particle surface adhesion energy based on a piezoelectric vibrator. The method is implemented based on the device described in the first embodiment and includes the following steps:

[0051] Step 1: Open the upper cover 2, rotate the fastening structure 8 until the lower surface of the horn 7 faces upward, and place particles on the lower surface of the horn 7 in a scattered manner; the particle picture at this time is as follows Figure 2 As shown in (a) in .

[0052] Step 2: Slowly rotate the fastening structure 8 until the lower surface of the horn 7 faces downward, and then cover the upper cover plate 2.

[0053] Step 3: Start the high-frequency signal generator to output a sinusoidal electrical signal with an amplitude of A and a frequency of f.

[0054] Step 4: After a period of time, turn off the high-frequency signal generator and use camera 4 to take a photo P1 of the particles falling on the transparent glass plate; the particle picture at this time is as follows Figure 2 As shown in (c) in .

[0055] Step 5: Open the upper cover 2, slowly rotate the fastening structure 8 until the lower surface of the horn 7 faces upward, and take a photo P2 of the particles on the lower surface of the horn 7; the particle picture at this time is as follows Figure 2 As shown in (b) in .

[0056] Step 6: Calculate the critical diameter d of the falling particles according to the following formula based on the particle photos taken;

[0057]

[0058] Wherein, d1 is the diameter of the largest particle in the particle photo P2, and d2 is the diameter of the smallest particle in the particle photo P1.

[0059] Step 7: Calculate the maximum acceleration a of the piezoelectric vibrator 6 based on the amplitude A and frequency f of the sinusoidal electrical signal MAX :

[0060] a MAX =-4kAπ 2 f 2

[0061] Where k is the magnification of the horn 7, The initial phase.

[0062] Maximum acceleration MAX The derivation process of the formula is as follows: According to the simple harmonic vibration of the piezoelectric vibrator, Figure 3 As shown, the up and down vibration displacement equation is:

[0063]

[0064] ω=2πf

[0065] Where ω is the angular frequency, The initial phase.

[0066] By continuously differentiating the vibration displacement equation twice, we can get the acceleration formula:

[0067]

[0068] From the above formula, we can get the maximum acceleration value of the piezoelectric vibrator:

[0069] a MAX =-4kAπ 2 f 2

[0070] Step 8: Based on the balance between the adhesion force and the vibration force when the particle is separated from the lower surface of the horn 7, the surface adhesion energy of the particle is obtained according to the following formula:

[0071]

[0072] Where ρ is the particle density and Г is the particle surface adhesion energy.

[0073] The derivation process of the above formula is as follows: The balance formula of adhesion force and vibration force is as follows:

[0074]

[0075] Rearranging the above formula, we get F ad and F v are the adhesion force and vibration force of the particles respectively.

[0076] The present invention utilizes the piezoelectric effect to balance the particle adhesion force and the vibration force so as to measure the particle adhesion energy. The experimental principle is simple and easy to understand, and the experimental operation is concise and efficient. A high-frequency signal generator is used as a signal source, so that the signal transmission is accurate and controllable. The device of the present invention is not limited to measuring dry powders, but can measure wet and oily powders, and the measurement types and measurement ranges are very wide. In the present invention, the experimental device is sealed in a cylindrical housing, and the surface adhesion energy of particles under different temperatures and humidities can be measured by controlling the sealing environment according to the experimental purpose. In the present invention, the problem of powder dispersion is solved by using an air pump. Since there are relatively mature devices and methods for powder dispersion, they are not repeated in the device and method of the present invention, and researchers can choose a method that suits them.

[0077] Embodiment 3

[0078] The embodiment of the present invention provides a particle surface adhesion energy measurement system based on a piezoelectric vibrator, comprising an apparatus of the embodiment 1 and a computer device, wherein the computer device comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the following steps:

[0079] Step 1: Obtain a photo P1 of particles falling onto the transparent glass plate after the high-frequency signal generator is started, and take a photo P2 of particles on the lower surface of the horn (7);

[0080] Step 2: Calculate the critical diameter d of the falling particles according to the following formula based on the particle photos taken;

[0081]

[0082] Wherein, d1 is the diameter of the largest particle in the particle photo P2, and d2 is the diameter of the smallest particle in the particle photo P1;

[0083] Step 3: Calculate the maximum acceleration a of the piezoelectric vibrator (6) based on the amplitude A and frequency f of the sinusoidal electrical signal emitted by the high-frequency signal generator. MAX :

[0084] a MAX =-4kAπ 2 f 2

[0085] Where k is the magnification of the horn (7), is the initial phase;

[0086] Step 4: Based on the balance between the adhesion force and the vibration force when the particle is separated from the lower surface of the horn (7), the surface adhesion energy of the particle is calculated according to the following formula:

[0087]

[0088] Where ρ is the particle density and Г is the particle surface adhesion energy.

[0089] The memory may include computer system readable media in the form of volatile memory, such as random access memory (RAM) and / or cache memory. The device may further include other removable / non-removable, volatile / non-volatile computer system storage media. By way of example only, the memory may be used to read and write non-removable, non-volatile magnetic media (commonly referred to as "hard drives"). A program / utility having a set (at least one) of program modules may be stored in, for example, the memory, such program modules including but not limited to an operating system, one or more application programs, other program modules, and program data, each of which or some combination may include an implementation of a network environment. The computer executable program of the program module typically performs the functions and / or methods in the embodiments described in the present invention.

[0090] The processor executes various functional applications and data processing by running the program stored in the memory, such as implementing the method provided in the first embodiment of the present invention.

[0091] The code of the computer executable program can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, C++, and conventional procedural programming languages ​​such as "C" language or similar programming languages.

[0092] It should be understood that the above embodiments and descriptions only describe the principles, main features and advantages of the present invention. Without departing from the spirit and scope of the present invention, the present invention may be subject to various changes and improvements, and these changes and improvements all fall within the scope of protection of the present invention.

Claims

1. A device for measuring particle surface adhesion energy based on a piezoelectric vibrator, characterized in that: The invention comprises a housing (1), a detachable upper cover (2), a lower cover (3), a camera (4), a transparent glass plate (5), a piezoelectric vibrator (6), a horn (7), a fastening structure (8) and a high-frequency signal generator, wherein the upper cover (2) is located above the housing (1), the lower cover (3) is fixed below the housing (1), the camera (4) is placed above the lower cover (3), the transparent glass plate (5) is fixed to a position above the camera (4) in the housing (1), the piezoelectric vibrator (6) and the horn (7) are fixed above the transparent glass plate (5) in the housing (1) via a rotatable fastening structure (8), the horn (7) is connected below the piezoelectric vibrator (6), and the high-frequency signal generator is connected to the piezoelectric vibrator (6) via a lead wire.

2. The device for measuring particle surface adhesion energy based on piezoelectric vibrator according to claim 1, characterized in that: The fastening structure (8) is specifically a detachable elastic fastening ring.

3. The device for measuring particle surface adhesion energy based on piezoelectric vibrator according to claim 2, characterized in that: Screw holes are provided on both sides of the fastening ring for installing screws to fix the piezoelectric vibrator (6) and the amplitude transformer (7).

4. The device for measuring particle surface adhesion energy based on piezoelectric vibrator according to claim 1, characterized in that: The outer shell (1) is provided with a plurality of first through holes, and the transparent glass plate (5) is fixed in the outer shell (1) via a plurality of cylindrical pins (9) inserted through the first through holes.

5. The device for measuring particle surface adhesion energy based on piezoelectric vibrator according to claim 1, characterized in that: The horn (7) is connected to the piezoelectric vibrator (6) by welding.

6. The device for measuring particle surface adhesion energy based on piezoelectric vibrator according to claim 2, characterized in that: The housing (1) is provided with two second through holes, and the two ends of the fastening ring are rotatably inserted into the second through holes, so that when the fastening ring rotates, the piezoelectric vibrator (6) and the amplitude transformer (7) are driven to flip.

7. The device for measuring particle surface adhesion energy based on piezoelectric vibrator according to claim 1, characterized in that: The outer shell (1) is a cylinder, and the transparent glass plate (5) is a circular plate having a radius equal to that of the inner radius of the outer shell (1).

8. The device for measuring particle surface adhesion energy based on piezoelectric vibrator according to claim 1, characterized in that: The camera (4) is specifically a CCD camera.

9. A method for measuring particle surface adhesion energy based on piezoelectric vibrator, characterized in that: The method is implemented based on the device described in claim 1, and comprises the following steps: Step 1: Open the upper cover plate (2), rotate the fastening structure (8) until the lower surface of the horn (7) faces upward, and scatter particles on the lower surface of the horn (7); Step 2: Slowly rotate the fastening structure (8) until the lower surface of the horn (7) faces downward, and then cover the upper cover plate (2); Step 3: Start the high frequency signal generator, the output amplitude is A , the frequency is f A sinusoidal electrical signal; Step 4: After a period of time, turn off the high-frequency signal generator and use the camera (4) to take a photo P1 of the particles falling on the transparent glass plate; Step 5: Open the upper cover plate (2), slowly rotate the fastening structure (8) until the lower surface of the horn (7) faces upward, and take a photo P2 of the particles on the lower surface of the horn (7); Step 6: Calculate the critical diameter of falling particles according to the following formula based on the particle photos taken d ; ， in, d 1 is the diameter of the largest particle in particle photo P2, d 2 is the diameter of the smallest particle in particle photo P1; Step 7: According to the amplitude of the sinusoidal electrical signal A and frequency f The maximum acceleration of the piezoelectric vibrator (6) is calculated as : , In the formula, k is the magnification of the horn (7); Step 8: Based on the balance between the adhesion force and the vibration force when the particle is separated from the lower surface of the horn (7), the surface adhesion energy of the particle is calculated according to the following formula: , in, ρ is the particle density, G is the particle surface adhesion energy.

10. A particle surface adhesion energy measurement system based on piezoelectric vibrator, characterized in that: The method comprises the apparatus according to claim 1 and a computer device, wherein the computer device comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the following steps: Step 1: Obtain a photo P1 of particles falling onto the transparent glass plate after the high-frequency signal generator is started, and take a photo P2 of particles on the lower surface of the horn (7); Step 2: Calculate the critical diameter of falling particles according to the following formula based on the particle photos taken d ; ， in, d 1 is the diameter of the largest particle in particle photo P2, d 2 is the diameter of the smallest particle in particle photo P1; Step 3: According to the amplitude of the sinusoidal electrical signal A and frequency f The maximum acceleration of the piezoelectric vibrator (6) is calculated as : , In the formula, k is the magnification of the horn (7); Step 4: Based on the balance between the adhesion force and the vibration force when the particle is separated from the lower surface of the horn (7), the surface adhesion energy of the particle is calculated according to the following formula: , in, ρ is the particle density, G is the particle surface adhesion energy.

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